When using the calculation of stability (regardless of the methodology that is being used), there are two approaches: deterministic and stochastic. The first prerequisite for any calculations is that there are enough data that can be processed statistically - to satisfy the Student classification. When using the deterministic method, the main value to be taken into account in the calculations is the mean value, whereas when using stochastic calculations, all the results obtained by laboratory or field examinations are equally represented. Thanks to this, non-homogeneity of the massif has been introduced to the calculations. This paper presents the methodology of stochastic calculations, and shows one example of comparative analysis of the results of stochastic and deterministic calculations

The stability analysis of rock slopes holds paramount importance in a multitude of geotech-nical projects, including rock-fill dams, embankments, as well as natural and excavated slopes. Among the various failure modes encountered in rock slopes, planar failure is a significant concern. Numerical analysis employing the Mohr-Coulomb linear criterion is a conventional approach adopted by engineers to evaluate the likelihood of planar failure within rock slopes. Nevertheless, the shear strength behavior of rock masses is universally recognized to exhibit nonlinear characteristics, rendering the Mohr-Coulomb criterion a simplified representation of a more complex reality. To bridge this gap, a range of nonlinear shear strength criteria has been formulated, aiming to more accurately depict the nonlinear behavior of rock masses. The objective of this paper is to provide novel insights into the stability analysis of rock slopes through the application of the Úcar nonlinear criterion. The outcomes demonstrate that the Úcar criterion, when juxtaposed with other nonlinear criteria reported in scholarly literature, provides a more precise estimation of the potential failure wedge.

Carbonate rocks have been widely used as a building material in architectural and civil engineering works due to their great availability and beauty. These geomaterials are frequently exposed to acidic aqueous conditions in outdoor environments that can reduce their durability. This study investigates the impact of immersion in acidic aqueous solutions prepared from hydrochloric acid on the physico-mechanical behaviour of a porous limestone from Alicante (Spain). For this purpose, physical characteristics (colour, density, porosity, P- and S-wave velocities and associated dynamic parameters) and mechanical properties (uniaxial compressive strength and Young's modulus) of limestone samples were determined in its initial intact state and after immersion for one month in acid and neutral solutions with pH values equal to 2, 4 and 7. The results revealed that the exposure of the limestone to the acid solutions increases its porosity and reduces its density, P- and S-wave velocities, uniaxial compressive strength and Young´s modulus, which can be attributed to the hydro-physico-chemical interactions between the minerals of the rock and the pore fluid. The knowledge obtained can serve as a basis for determining the suitability of the use of the studied building rock in acidic aqueous environments such as those generated by acid rain or bio acid attack (e.g., lichens) and for establishing the preventive conservation actions to be conducted in heritage constructions built with this stone.

In many fracture mechanics tests, starter notches are commonly carved in samples to generate a small-size region with high-stress concentration in a precise location of the sample of interest. Contrary to other materials where fatigue pre-cracking is possible, starter notches had to be cut in rocks. A variety of techniques exist, but the most common way is to use sawing or milling techniques. Leaving aside the requirements of precise alignment of the notch with respect the specific geometry of the sample and stress orientation, the intrinsic properties of the notch (e.g., sharp or blunt, thick or thin) likely affect the shape and extent of the fracture process zone (FPZ) ahead the crack tip and the fracture toughness (K_C) itself. In this contribution the effect of cutting a relatively thick (~1 mm using a diamond saw disk) and thin (~0.3 mm using a diamond saw wire) starter notch in 4 distinct rock types with apparent macroscopic homogeneity: Moleanos limestone, Floresta sandstone and Macael and Carrara marbles is analyzed. In the two cases, the shape of the edge of the notch is blunt but with a different radius of curvature. Samples were characterized in advance of testing (V_P & V_S, X-ray micro-FRX) to evaluate the homogeneity of the specimens. Then, fracture toughness tests (12 samples per rock type: 6 with the thick and 6 with the thin notch; 48 samples in total) have been performed using the pseudo-compact tension (pCT) technique, which is intended for the precise assessment of this property in mode I (tension). Some of the tests were also complemented with Digital Image Correlation (DIC) observations focused in the FPZ region. Results show that macroscopic (de visu) homogeneity criterion is not enough to guarantee homogeneous mechanical results. With respect the effect of starter notch thickness, we observe that, within uncertainty, there is no significant difference in K_IC (in MPa m^½) in the case of the Floresta sandstone (thin notch = 0.40±0.01; thick notch = 0.37±0.01) and the Macael marble (thin notch = 1.03±0.04; thick notch =1.07±0.06) while that difference is a little bit more significant in the case of the Moleanos limestone (thin notch = 0.85±0.05; thick notch = 0.93±0.03) and, especially in the case of the Carrara marble (thin notch = 0.75±0.05; thick notch =0.93±0.05).

The historic center of Salobreña (Granada, Spain), is located on the summit of a 100-meter-high promontory of Triassic marbles rock known as “La Peña del Castillo”. In this area, rockfalls of different magnitudes have occurred, some of them at the foot of Salobreña Medieval Castle. Recent events in November 2019 and June 2022 have caused significant social alarm due to their impact on the access roads and assets. Fortunately, there were no reported fatalities. To evaluate the fracturing of rock massif, data from discontinuities families were col-lected using (1) geomechanical in-situ stations, as well as (2) applying remote sensing techniques like LiDAR, and another tools, more cost-effective and accessible than LiDAR instrumentation, that combines drone flights and the application of Structure-from-motion (SfM) technique. After applying each technique individually, the discontinuity families have been evaluated and combined.

Located on the border between Zambia and Zimbabwe, the Kariba Dam was constructed on the Zambezi river between 1956 - 1959, creating the largest man-made lake by reser-voir volume. Heavy spillages have progressively scoured an 80 m deep plunge pool, im-mediately downstream of the dam, threatening its foundations. Given the importance of the dam, the decision to undertake the Kariba Dam Rehabilitation Project (KDRP) to en-sure its longevity, long term efficient operation and its continued contribution to energy security and economic prosperity in the region was made. Under the KDRP, the plunge pool reshaping works seek to reshape the plunge pool, in-creasing the basin energy dissipative capacity to reduce the backward scour towards the dam foundations. The nature of the project, with an open-pit excavation at the foot of an existing dam in full operation is unprecedented and constitutes a real rock engineering challenge. This paper highlights the design activities carried out during the works.

This paper explores the mechanical behavior of phyllite rocks and their relationship with factors that can act as determinants in a slope failure: quartz content, tectonics and rock weathering. The rock failure occurred on the cut-slope of the A-7 highway (SE Spain), impacting metamorphic rocks such as phyllite, slate and quartzite sandstones. The geometric char-acteristics of the slope rupture resemble those of soil, despite the affected materials are rocks. Slope instability affects rocks within the hanging wall block of an E-dipping normal fault, while the footwall block, primarily composed of quartzite rocks, remained stable. This study reveals that in the fault gouge zone, the neoformation of expansive clay minerals takes place. Conse-quently, the pelitic nature of the phyllite rocks, combined with tectonically induced alteration, may have been the main determining factor causing these rocks to behave like soil.

To reduce dilution is the main objective in mining operations. For this case, it is necessary to improve the mine operations and define geotechnical parameters. To reduce dilution, the face drilling and charging standards should be improved as much as possible. Damage zone for the rock mass is another parameter to consider reducing dilution. Improvements began to reduce dilution regarding these issues at Tuprag Efemçukuru Gold Mine where the mining methods are long hole open stope, blind up hole and drift and fill. Initially, string loading was applied on face contour drills and the quality of parallel drillings was improved. In addition to operational applications, geotechnical parameters were correlated with overbreak. The cores for all infill drills have been logged with Barton Q system for geotechnical assessments at Tuprag Efemçukuru Gold Mine. Geotechnical core logging provides useful information to reveal damage zone. According to Q values of drifts, the face contour drillings have been relocated to inside the design for definition of damage zone. The overbreak results have been correlated with Q values section by section to create a legend to locate of the face contour drillings on the design. Q values, overbreak length, relocation distance of the face contour drillings on the design and drill hole diameter parameters were considered to calculate damage zone length for the back and the walls. Due to calculation, spots of each result have been put on damage zone length – Q values graphics for the back and the walls. Distribution of spots created a range on the graphics of the back and the walls. Maximum and minimum limits of the range for the back and the walls were drawn and emerged their formulas on the graphics. Consequently, created legend to relocation inside the design of the face contour drillings was revised with the formulas. A block model, based on the legend, was created as a guide for recommendation to operations. Stopes which have similar rock mass quality were compared as after and before applications to knowledge of benefits. The results showed dilution to reduce for ore drifts between 4% and 15% and for waste drifts between 6% and 11%. Besides, it supplied yield for diesel consumption, consumable consumption, and duration of operation cycle

The weathering process significantly affects the mineralogical and geochemical characteristics of rocks that finally alters the engineering properties of rocks. Three different weathering grades (fresh, slightly, and moderately weathered) of gneiss were collected from Kullu, Himachal Pradesh, India. A comprehensive qualitative and quantitative description is used to point out the weathering grades of gneissic rock. The mineralogical alterations were determined using thin-section analysis. The petrographic analysis revealed that a major alteration was observed in plagioclase feldspar. The sericitization of plagioclase is mainly noticed with progressive weathering. The quartz grains remain intact and unaltered in fresh and slightly weathered stages while minor fracturing was observed in the moderately weathered stage. The partial transformation of biotite was also observed in moderately weathered gneiss. The chemical composition of these three weathering grades of gneiss was determined using X-ray fluorescence (XRF) analysis. The Plagioclase Index of Alteration (PIA) shows a significant increase with increasing weathering grades that supports the higher alteration of plagioclase during the weathering of gneissic rock of Himachal Pradesh, India.

Rock bolting, rock reinforcement is an ongoing work. Its a necessity in all rock excavation related application areas i.e. in civil infrastrcuture projects, underground mining, open pit mining, tunneling etc. The subject of rock reinforcement, rock bolting is contineoulsy evolving and there has been a lot of new developments has happened over the years e.g. new types of rock bolts, development of rock bolting-reinforcement machines, design methdologies, application process etc. This paper will be specifically focusing on open rock slopes above ground. We have observed an application and methodological process error for applying rock reinforcement, rock bolting on an open rock slopes above ground. The problem is our current practice of installing rock bolts or rock reinforcement on rock slopes above ground is either based on random observation or systematic empirical design formula. In author's view, most of the time existing way of installing rock bolts, rock reinformcement miss to consider the impact of structural geology, geometry, gravational slip surface of rock blocks. In this paper we are presenting a new approach called 'cross-bedding-cross-bolting (CBRB)' for open rock slopes above ground. This new approach and application methodology for open rock slopes above ground mainly consider structural geology, geometry and gravational slip surface of rock blocks. We will present the conceptual theroy as well as the applicaiton methodology of the 'cross-bedding-cross-bolting (CBRB)' approach. The paper will also brifely review and present the existing practices for rock bolting, rock reinforcement, standards followed and application methodology. Our expected out come from this paper is to present a safe and cost efective method for securing open rock slopes above ground. Also, to provide a new approach and corrective measures for application of rock bolt, rock reinforcement for open rock slopes above ground.

Mine tunnels are constructed to offer access for various purposes. The tunnel excavation's primary purpose in this specific mine was to provide ventilation and access to the second-ary orebody. The Malmani dolomites, which contain most natural water resources, directly overlie the Black Reef formation, which is composed of extremely fine to silt quartzite in-terbedded with silt carbonaceous shale. Unexpected ground conditions caused significant delays during the tunnel construction (e.g., fault zone, dykes, laminated carbonaceous shales). After the inception of the fault zone, the tunnel construction could only advance for 9 m. The tunnel construction halted due to the porous ground conditions of the carbo-naceous shale that could not be supported. The layered carbonaceous rock mass presented difficulties due to its geochemical degradation. A suitable feasibility geotechnical program would have aided in the viability of excavating this tunnel within the Malmani dolomites and the possible risk of mining into the water compartments

Rock mass classifications have gained great importance for the last decades for tunneling engineering. Apart from some previous attempts along the XX century, the start of the rock mass classifications can be stated during the 70s with the development of the Rock Mass Rating (RMR) and the Q index, which are regarded at present as the references for most of the technicians, engineers and geologists. More recently, other classifications have been proposed, like the Geological Strength Index (GSI) and the Rock Mass Index (RMi), which are attracting more interest. Unlike in other fields, authors of those rock mass classifications suggested employing more than one system with the aim of capturing different aspects of the rock mass as each of them considers different factors for calculating the value. Therefore, some correlations have been proposed between two of the classifications for obtaining the rate in other system when having one of them. This paper aims to advance in this field and observe if it is feasible to correlate these four rock mass classifications: RMR, Q index, GSI, and RMi. With this aim, the data obtained from the Seberetxe tunnel, with approximately 600 m, in the new segment of the Southern Metropolitan By-Pass of Bilbao, in Spain, was employed. This twin tunnel was excavated by drill and blast in siltstone. Results indicate that the four systems can be correlated with acceptable accuracy in a homogeneous rock type with different weathering. This study shows that correlations can be developed between two of the four rock mass classifications as long as the same rock type is analyzed.

The rock mass is composed of homogeneous and heterogeneous rocks, where the stresses are transmitted with their specific values by: condition, depth and properties of the rocks; each stress has three components with their respective direction and their respective magnitude, being the major principal stress σ1, and the minor principal stresses σ3 and σ2. In the rock massif, stresses are recognized by their influence on underground excavations and must be measured. To measure in situ stresses, the Drillhole Detonation Method (DDM) is proposed, which detects stresses in two processes. 1) Detonation of a drillhole obtaining radial cracks of different length and direction, by joining the ends of the cracks elliptical figures are formed called ellipse of stresses whit their major and minor axes. 2) To evaluate the magnitude of the major stress we use the formula σ1 = FC1 · γ · Z, to evaluate the magnitude of the minor stress we use the formula σ3 = FC3 · k · γ · Z. The Correction Factor (CF) = 0.0056 (measured angle) + 1.003 and the coefficient k is obtained by dividing the length of the horizontal axes by the vertical axes of the ellipse. To obtain the direction and magnitude of σ2 a drilhole is detonated in the direction perpendicular to what has been done to obtain σ1 and σ3. The major axis of the stress ellipse represents σ1. The measurement of stresses by the Drillhole Detonation Method (DDM) is: low cost, calculated at the same time, contributes to optimize the support of underground excavations.

The term discontinuity covers a series of geological structures, very different both in origin and mechanical behavior. It includes the formational planes, like bedding planes and foliation planes, moving fractures and the joints. In order to perform more realistic geomechanical classification and modeling, for the geomechanical rock mass classifications, the term discontinuity should allow to differentiate between the formational structural planes, not related to the stress state, and the joints, that actually depend on the regionally and local stresses. Another inconsistency arises when evaluating roughness, since joints cannot present polished planes, which can apply to moving fractures, in general with different mechanical behaviors from each other. The same is true when applying the term persistence to a formational plane, whose extension is infinite when compared to a recent fracture or a joint. According to recent research results of stability analysis in tunnels and rock slopes, related to the new application criteria for joint formation based on changes in confining forces, this paper proposes the need for a new approach in the application of terminology for the rock mass geomechanical classification and for the geotechnical characterization, eliminating the inconsistencies that arise when applying some definitions indiscriminately to any structure and origin of the plane.

The slope stability analysis, the critical height, the estimation of force on retaining walls or the calculation of the anchor force, requires a mathematical formulation that goes through an optimization process to determine the critical sliding surface. The process consists of the solution of a derivative with respect to the critical surface. The analytical solutions that have been found are based on a simple geometry for a triangular shaped sliding body. In this paper a solution procedure is proposed for cases of any geometry, including complex geometries. A simple numerical method called incremental method, is developed, specially designed for the analysis of stability, thrust or anchorage design by means of a spread-sheet. The methodology allows static or pseudo-static analysis. Several analysis cases are shown and their solution is compared with the results using advanced numerical methods, where an excellent correspondence is demonstrated.

In this investigation, two different cooling techniques (i.e. water- and air-cooling methods) has been used in order to study the influence of different heating-cooling treatments on the physical properties, microstructural characteristics and point load strength of Himalayan granite collect-ed from Sangla valley, Himachal Pradesh. The temperatures for heat treatment were targeted at 100, 300, 400, 500 and 600°C. As a response to thermal treatments, increase in effective po-rosity and increase in damage coefficient occurs which causes exponential decrease in point load strength. It decreases ~74% and ~81% under air-cooling and water cooling respectively after heating of about 600oC with reference to thermally untreated specimens. The microstruc-tural study reveals that the increase in crack density due to thermal treatments induce intra-, in-ter- and trans-granular cracks, at and beyond 300oC onwards and their coalescence with each other at higher temperatures (i.e. ≥ 500oC) under both the thermal treatments contribute to-wards the variation in point load strength of thermally treated granites.

This study investigates the influence of flaw inclination angles on the mechanical response of rock-like specimens with pre-existing flaws under dynamic loading conditions, employing the Discrete Element Method (DEM) software UDEC. Several Split Hopkinson Pressure Bar (SHPB) compression tests were previously conducted on these specimens, each containing a single non-persistent flaw. The study considered two flaw orientations and a single flaw. Earlier experimental investigations revealed that specimens with unfilled flaws exhibited the highest dependency on flaw inclination angle. Notably, the weakest mechanical response for flawed specimens was observed at a 30° flaw orientation, aligning with the shear failure plane of intact specimens. UDEC numerical simulations were performed to further elucidate the experimental findings. The peak stress response of flaw models obtained were less than intact rock models, which matched well with the experimental results. These simulations provided invaluable insights into the dynamic behaviour of rock-like specimens. .

This study addresses the challenge of accurately estimating support forces to mitigate rock slope failures, employing inverse reliability methods like the Performance Measure Approach (PMA) and the Probabilistic Sufficiency Factor (PSF). A comparison with conventional for-ward reliability approaches, such as the Reliability Index Approach (RIA) and the Forward Monte-Carlo Approach (FMC), highlights the advantages of inverse reliability methods. Focusing on wedge-shaped failure scenarios in the Himalayas, the research emphasizes the applicability and effectiveness of the PMA and the PSF. Results indicate that these inverse methods offer improved accuracy and computational efficiency compared to traditional approaches, making them valuable tools for support force estimation in rock slope engineering. Their reduced computational effort enhances practical applicability, positioning them as promising alternatives in the field.

For coal extraction and removal of overburden, blasting is commonly used in most open-pit coal mines. Blasting generates shock energy that crushes the rock initially and then propagates in the form of waves through the surrounding rock. These ground vibrations are detrimental to the safety of the structures that are located in the vicinity. Though the interaction between blast waves and different structures has been extensively studied to safeguard these structures, the specific behaviour of brick masonry structures under blast-induced ground vibrations (BIGV) remains largely unexplored. The influence of BIGV on structural safety necessitates the incorporation of dynamic structural characteristics into safety guidelines to ensure the safeguarding of these structures. In order to investigate the actual behaviour of structures located near the periphery of a mine, a brick masonry wall was modeled in ABAQUS and analysed under the influence of 10 ground vibration time histories from distinct blast events with varying PPV (Peak Particle Velocity) values. A simplified micro modeling approach utilizing the CDP (Concrete Damage Plasticity) model was employed to accurately predict the wall's response. A comparative analysis was conducted, revealing contrary to popular beliefs, that even at very low PPV values, the structure exhibited significant deformations and stresses. Conversely, in some instances with very high PPV values, the structure remained safe. The primary finding underscores that using PPV alone as the determinant of structural safety possesses several limitations. It is imperative to consider the dynamic characteristics of structures in blast designs for a more comprehensive assessment of safety.

Thermal properties describe how heat and temperature behave in a rock. Sandstone is a very common sedimentary rock found in layers formation in coal mining areas. This rock is used for underground backfilling purposes and other applications in mining. For optimizing the heat load in underground mines, the thermal properties of sedimentary rock are very important. We analyze the results of measurements of the thermal properties, porosity and density of sandstone rocks from the Godavari coal basin, Telangana. The thermal properties were measured by the “FOX50” instrument at room temperature (25⁰C). The thermal conductivity of sandstone rocks ranges from 0.65 to 4.38 W/m. K and it is strongly depending on porosity and density. The average range of density of rock samples is 2.28 to 2.50 g/cm³ and average porosity ranges from 6 to 13 %. The results indicate variations in thermal conductivity and diffusivity across different locations, while specific heat appears consistent throughout all regions. The study also investigated how density and porosity affect the thermal properties of rocks. It was found that thermal conductivity increases with density and decreases with porosity. The assessment of thermal conductivity from porosity and density is made possible by the equations that are provided.

Investigating the possible correlation between various measures of rock strength is a common practice in experimental rock mechanics, as the results of relatively simple and economical tests can yield estimates of mechanical properties that would require more sophisticated experimental procedures. For example, the Schmidt hammer test is one of these experimental setups that have been used to indirectly determine the uniaxial compressive strength and the static modulus of elasticity. Nevertheless, this experimental setup has not been extensively used for the indirect determination of other important mechanical properties, such as the point load strength index and the indirect tensile strength obtained from the Brazilian strength test. For this reason, an experimental program was carried out involving at first the direct determination of the Schmidt hardness, the point load strength index, and the Brazilian tensile strength for rock types of various origins outcropped at the southern part of the Attica Peninsula, Greece. Subsequently, the statistical processing of these results was performed via simple regression techniques, while very good relations were established in the form of exponential equations between the Schmidt hardness and both the point load strength index and the Brazilian tensile strength. Our results can be used for preliminary investigations, at least in the study region, and can enrich our knowledge regarding the correlation between the mechanical properties under consideration.

Traditionally employed laboratory tests allow obtaining strength and deformation properties of rocks, such as the uniaxial compressive strength, tensile strength and Young's modulus. Andesite, a pivotal rock in Ecuador, holds significant relevance to civil engineering and mining, yet its geomechanical properties remain inadequately explored. This study delves into the physical, petrographic, and geomechanical characteristics of andesite from the Tungurahua volcanics geological unit in the Real Cordillera of the Ecuadorian Andes. The findings reveal a massive andesite with porphyritic and hyalopilitic textures, boasting high density (2690±36 kg/m³), low porosity (2.11±1.32%), and minimal water absorption (0.31±0.13%). Mechanically, it proves to be a high-strength rock (204 MPa) with nonlinear elastic behavior up to 40% of the maximum strength and an average secant Young's modulus of 35.06±2.47 GPa. These results contribute to enhance our understanding of Andean andesite properties from the Tungurahua volcanics geological unit.

Limit States Design (LSD), which represents an implementation of Reliability Based Design (RBD), is becoming more widely used in geotechnical engineering. Fundamentally this requires a probabilistic characterization of all uncertainties in a given geotechnical engineering problem. Uncertainty is inherent to rock mechanics and rock engineering, and generally stems from factors such as complex geology, vagueness in instability mechanisms and the highly nonlinear mechanical behaviour of rock masses. Such uncertainties are commonly considered using subjective qualitative assessments, SQAs, using what are known as linguistic variables, e.g. a rock mass may be described as being “slightly weathered”. In this paper we demonstrate why SQAs must be considered as ordinal and not metric (i.e. measured) values. We thus show both why it is not possible to directly consider SQAs in a probabilistic setting, and how doing so may lead to significant errors. To overcome this severe limitation of SQAs we apply techniques recently developed in the broader field of imprecise probabilities in engineering analyses. In particular, we examine how SQAs may advantageously be firstly converted into fuzzy numbers and from those into probabilistic variables. An immediate benefit of this approach is that conditional probability can be used to examine situations where both quantitative measurements (e.g. intact rock strength) and SQAs exist. We demonstrate this by constructing a Bayesian network that combines the two characteristics of intact rock strength and degree of weathering, and show how this leads to an interpretation of rock mass condition that directly supports LSD. Using an example from the literature, we conclude with a brief discussion of how such Bayesian networks can be applied to complex rock engineering projects.

This study assesses the influence of petrophysical properties, petrographic features, and depth on capillary imbibition of basalts and lapillistones from the Upper and Middle Vol-canic Complexes of Madeira Island, Portugal, via multivariate statistical analyses and ma-chine learning methods approach. Results demonstrated that the combined effect of mesofabric, porosity, and pore-type connectedness controls capillary imbibition in lapillis-tones and revealed that there is a strong direct relationship between porosity degree and water absorption coefficient by capillarity, C, in all basalts. The tendency for spontaneous imbibition to decrease with increasing depth is as expected in the studied basalts, except for the sections 23.70 27.20 m and 31.5 34.8 m in two different samples where evidence of fracturing episodes was found which leads to a dual-porosity system that favours water absorption. C is proposed as a complementary coefficient in geotechnical studies of vol-canic rocks.

Pore microstructure in rocks regards shape, volume concentration, distribution and connectivity of pores and cracks and has a substantial influence on many macroscopically observed properties such as rock strength and its deformation and fracture behaviour. Cracks in rocks initiate and propagate in response to the applied stress, with the crack path often driven by local distribution of micro-flaws such as cavities, inclusions, fossils, grain boundaries, mineral cleavage planes, and micro-cracks inside the rock. For sedimentary rocks like sandstone, mineralogical composition of interstitial materials between framework grains is also important factor influencing crack parameters. Although these phenomena are generally known and widely described in the macroscale or mesoscale, the microscopic aspects have not been studied very extensively yet. In order to better understand the process which leads from micro-cracks to macroscopic fracturing and thus extends in scale from millimetres to kilometres, the crack initiation, propagation and growth should be studied just in the microscale. In practical terms, knowledge of the failure behaviour of rock mass due to crack propagation is much needed in some important engineering cases, such as, CO₂ sequestration, high-level radioactive waste disposal or stability of underground workings and slopes. In this contribution, the basic outputs of the study of influence of rock microstructure and composition on the fracture toughness of rocks measured by the chevron notch technique and subsequent analysis of cracks geometry using the X-ray computed tomography are presented. Rock samples selected for experiments are representatives of all three major groups of rocks (igneous, sedimentary and metamorphic), from which sediments, namely sandstones, are the most numerous. Four basic crack parameters were investigated on all rock specimens: (1) crack length, (2) crack width, (3) angle of crack deflection from crack initiation zone, and (4) description of crack course. On the basis of laboratory experiments and analyses, the following fundamental conclusions can be made: (1) the value of crack length generally increases with decreasing rock porosity and this trend is most pronounced within the sandstones, (2) the value of crack length generally increases with increasing value of fracture toughness, (3) the value of the crack length of the sandstones increases with a growing degree of silicification of the matrix, (4) in sandstones, the cracks propagation goes preferably throughout the pore space and may be influenced by limonite pigment and (5) in low-porosity crystalline igneous and metamorphic rocks, the cracks spread along the grain boundaries and often also break grains.

Erosion can cause irreparable damage when it occurs on elaborated elements of the cultural heritage. Even very small erosion rates can result in the loss of valuable sculptural details. Rock erodibility is defined as the lithology-based susceptibility to erosion for a given set of environmental conditions. Wind, rain and hail are examples of the main erosion agents affecting the building rocks used in architectural heritage. Human activity can also be the cause of severe erosion processes in rocks. However, the rock suscebility to erosion determines the efficacy of the erosive process and the effective final material loss from the stone surface. Several research lines address the study of rock erodibility in different contexts (fluvial geomorphology, generation of sediments, tunnel construction, etc.) offering a quantitative approach using indices. However, there are very few works focused on the erodibility of rocks in the heritage context. Erosion, weathering and durability are closely related concepts, usually considered synonymous, but they require an individualized study since the effects and causes associated with each process are very different. In this work, a first approach is proposed to the study of the susceptibility to the erosion of four building rocks widely used in the cultural heritage of Spain. Selected rocks are porous limestones and sandstones with porosity higher than 10%. These rock types are frequent in architectural heritage due to both their availability and their high workability. Erosion Susceptibility of studied rocks has been analysed taking into account both petrographic (texture, structure, mineralogy, heterogeneity and anisotropy) and petrophysical (porosity, pore size distribution and mechanical properties) aspects. The resistance to erosion has been determined by means of the laboratory wide wheel abrasion test. Results show that erosion susceptibility is directly correlated with porosity and inversely with mechanical properties. Grain cohesion, friction angle and tensile strength are key parameters to determine erodibility. Mineralogy probably modify the susceptibility to the material loss, being more resistant the quartz-based rocks than the limestones. Future works, however, should verify the results obtained in this approach including new data and new rock types.

This work presents a multiproxy methodology that combines both in-situ outcrop tests and la-boratory methods, for the petrophysical characterization of a potential sandstone CO2 reservoir. Multiproxy methodology was designed to obtain a complete petrophysical and geomechanical characterization including non-conventional techniques in this type of study. Considered sandstone reservoir corresponds to a detrital Buntsandstein facies of the Iberia Chain (central Spain). Specifically, the involved formations are Aranda-Carcalejos (possible reservoir) and Rané (seal). Four main facies were recognized in the stratigraphic sequence, and the petrophysical analysis of each one was carried out. Main petrophysical differences are found between both channel and sheetflood facies, the former being much more porous and permea-ble and less mechanically resistant than the sheetflood facies. The comparative analysis also highlights the strengths and weaknesses of this multiproxy methodology. This work is part of the in-deep geological characterization of a geological complex for CO2 storage potential evaluation.

In the present paper, statistically significant correlations are obtained between sample di-mensions: height H, width W, and length L, on one side, and compressive strength σp and resistance to cutting KL of the clay sample, on the other side. The geomechanical proper-ties of the coal overburden are determined in laboratory conditions. Coal overburden has a predominantly clayey-silty composition, and samples were taken from the Tamnava East-ern Field (Serbia). Laboratory data are analyzed using multiple linear regression. Results obtained indicate the existence of statistically significant correlations between sample sizes and both σp and KL. These correlations are presented in the form of explicit nonlinear mathematical expressions with corresponding diagrams, which enable further quantitative and qualitative interpretation of the mutual interaction of the analyzed geometrical and ge-omechanical properties. Obtained correlations are with high values of the determinism co-efficient (R > 0.9) and low values of standard deviation. Results are further verified using the ANOVA test. Critical values for certain sample dimensions regarding their effect on σp and KL.

When using the calculation of stability (regardless of the methodology that is being used), there are two approaches: deterministic and stochastic. The first prerequisite for any calculations is that there are enough data that can be processed statistically - to satisfy the Student classification. When using the deterministic method, the main value to be taken into account in the calculations is the mean value, whereas when using stochastic calculations, all the results obtained by laboratory or field examinations are equally represented. Thanks to this, non-homogeneity of the massif has been introduced to the calculations. This paper presents the methodology of stochastic calculations, and shows one example of comparative analysis of the results of stochastic and deterministic calculations

The stability analysis of rock slopes holds paramount importance in a multitude of geotech-nical projects, including rock-fill dams, embankments, as well as natural and excavated slopes. Among the various failure modes encountered in rock slopes, planar failure is a significant concern. Numerical analysis employing the Mohr-Coulomb linear criterion is a conventional approach adopted by engineers to evaluate the likelihood of planar failure within rock slopes. Nevertheless, the shear strength behavior of rock masses is universally recognized to exhibit nonlinear characteristics, rendering the Mohr-Coulomb criterion a simplified representation of a more complex reality. To bridge this gap, a range of nonlinear shear strength criteria has been formulated, aiming to more accurately depict the nonlinear behavior of rock masses. The objective of this paper is to provide novel insights into the stability analysis of rock slopes through the application of the Úcar nonlinear criterion. The outcomes demonstrate that the Úcar criterion, when juxtaposed with other nonlinear criteria reported in scholarly literature, provides a more precise estimation of the potential failure wedge.

Carbonate rocks have been widely used as a building material in architectural and civil engineering works due to their great availability and beauty. These geomaterials are frequently exposed to acidic aqueous conditions in outdoor environments that can reduce their durability. This study investigates the impact of immersion in acidic aqueous solutions prepared from hydrochloric acid on the physico-mechanical behaviour of a porous limestone from Alicante (Spain). For this purpose, physical characteristics (colour, density, porosity, P- and S-wave velocities and associated dynamic parameters) and mechanical properties (uniaxial compressive strength and Young's modulus) of limestone samples were determined in its initial intact state and after immersion for one month in acid and neutral solutions with pH values equal to 2, 4 and 7. The results revealed that the exposure of the limestone to the acid solutions increases its porosity and reduces its density, P- and S-wave velocities, uniaxial compressive strength and Young´s modulus, which can be attributed to the hydro-physico-chemical interactions between the minerals of the rock and the pore fluid. The knowledge obtained can serve as a basis for determining the suitability of the use of the studied building rock in acidic aqueous environments such as those generated by acid rain or bio acid attack (e.g., lichens) and for establishing the preventive conservation actions to be conducted in heritage constructions built with this stone.

In many fracture mechanics tests, starter notches are commonly carved in samples to generate a small-size region with high-stress concentration in a precise location of the sample of interest. Contrary to other materials where fatigue pre-cracking is possible, starter notches had to be cut in rocks. A variety of techniques exist, but the most common way is to use sawing or milling techniques. Leaving aside the requirements of precise alignment of the notch with respect the specific geometry of the sample and stress orientation, the intrinsic properties of the notch (e.g., sharp or blunt, thick or thin) likely affect the shape and extent of the fracture process zone (FPZ) ahead the crack tip and the fracture toughness (K_C) itself. In this contribution the effect of cutting a relatively thick (~1 mm using a diamond saw disk) and thin (~0.3 mm using a diamond saw wire) starter notch in 4 distinct rock types with apparent macroscopic homogeneity: Moleanos limestone, Floresta sandstone and Macael and Carrara marbles is analyzed. In the two cases, the shape of the edge of the notch is blunt but with a different radius of curvature. Samples were characterized in advance of testing (V_P & V_S, X-ray micro-FRX) to evaluate the homogeneity of the specimens. Then, fracture toughness tests (12 samples per rock type: 6 with the thick and 6 with the thin notch; 48 samples in total) have been performed using the pseudo-compact tension (pCT) technique, which is intended for the precise assessment of this property in mode I (tension). Some of the tests were also complemented with Digital Image Correlation (DIC) observations focused in the FPZ region. Results show that macroscopic (de visu) homogeneity criterion is not enough to guarantee homogeneous mechanical results. With respect the effect of starter notch thickness, we observe that, within uncertainty, there is no significant difference in K_IC (in MPa m^½) in the case of the Floresta sandstone (thin notch = 0.40±0.01; thick notch = 0.37±0.01) and the Macael marble (thin notch = 1.03±0.04; thick notch =1.07±0.06) while that difference is a little bit more significant in the case of the Moleanos limestone (thin notch = 0.85±0.05; thick notch = 0.93±0.03) and, especially in the case of the Carrara marble (thin notch = 0.75±0.05; thick notch =0.93±0.05).

The historic center of Salobreña (Granada, Spain), is located on the summit of a 100-meter-high promontory of Triassic marbles rock known as “La Peña del Castillo”. In this area, rockfalls of different magnitudes have occurred, some of them at the foot of Salobreña Medieval Castle. Recent events in November 2019 and June 2022 have caused significant social alarm due to their impact on the access roads and assets. Fortunately, there were no reported fatalities. To evaluate the fracturing of rock massif, data from discontinuities families were col-lected using (1) geomechanical in-situ stations, as well as (2) applying remote sensing techniques like LiDAR, and another tools, more cost-effective and accessible than LiDAR instrumentation, that combines drone flights and the application of Structure-from-motion (SfM) technique. After applying each technique individually, the discontinuity families have been evaluated and combined.

Located on the border between Zambia and Zimbabwe, the Kariba Dam was constructed on the Zambezi river between 1956 - 1959, creating the largest man-made lake by reser-voir volume. Heavy spillages have progressively scoured an 80 m deep plunge pool, im-mediately downstream of the dam, threatening its foundations. Given the importance of the dam, the decision to undertake the Kariba Dam Rehabilitation Project (KDRP) to en-sure its longevity, long term efficient operation and its continued contribution to energy security and economic prosperity in the region was made. Under the KDRP, the plunge pool reshaping works seek to reshape the plunge pool, in-creasing the basin energy dissipative capacity to reduce the backward scour towards the dam foundations. The nature of the project, with an open-pit excavation at the foot of an existing dam in full operation is unprecedented and constitutes a real rock engineering challenge. This paper highlights the design activities carried out during the works.

This paper explores the mechanical behavior of phyllite rocks and their relationship with factors that can act as determinants in a slope failure: quartz content, tectonics and rock weathering. The rock failure occurred on the cut-slope of the A-7 highway (SE Spain), impacting metamorphic rocks such as phyllite, slate and quartzite sandstones. The geometric char-acteristics of the slope rupture resemble those of soil, despite the affected materials are rocks. Slope instability affects rocks within the hanging wall block of an E-dipping normal fault, while the footwall block, primarily composed of quartzite rocks, remained stable. This study reveals that in the fault gouge zone, the neoformation of expansive clay minerals takes place. Conse-quently, the pelitic nature of the phyllite rocks, combined with tectonically induced alteration, may have been the main determining factor causing these rocks to behave like soil.

To reduce dilution is the main objective in mining operations. For this case, it is necessary to improve the mine operations and define geotechnical parameters. To reduce dilution, the face drilling and charging standards should be improved as much as possible. Damage zone for the rock mass is another parameter to consider reducing dilution. Improvements began to reduce dilution regarding these issues at Tuprag Efemçukuru Gold Mine where the mining methods are long hole open stope, blind up hole and drift and fill. Initially, string loading was applied on face contour drills and the quality of parallel drillings was improved. In addition to operational applications, geotechnical parameters were correlated with overbreak. The cores for all infill drills have been logged with Barton Q system for geotechnical assessments at Tuprag Efemçukuru Gold Mine. Geotechnical core logging provides useful information to reveal damage zone. According to Q values of drifts, the face contour drillings have been relocated to inside the design for definition of damage zone. The overbreak results have been correlated with Q values section by section to create a legend to locate of the face contour drillings on the design. Q values, overbreak length, relocation distance of the face contour drillings on the design and drill hole diameter parameters were considered to calculate damage zone length for the back and the walls. Due to calculation, spots of each result have been put on damage zone length – Q values graphics for the back and the walls. Distribution of spots created a range on the graphics of the back and the walls. Maximum and minimum limits of the range for the back and the walls were drawn and emerged their formulas on the graphics. Consequently, created legend to relocation inside the design of the face contour drillings was revised with the formulas. A block model, based on the legend, was created as a guide for recommendation to operations. Stopes which have similar rock mass quality were compared as after and before applications to knowledge of benefits. The results showed dilution to reduce for ore drifts between 4% and 15% and for waste drifts between 6% and 11%. Besides, it supplied yield for diesel consumption, consumable consumption, and duration of operation cycle

The weathering process significantly affects the mineralogical and geochemical characteristics of rocks that finally alters the engineering properties of rocks. Three different weathering grades (fresh, slightly, and moderately weathered) of gneiss were collected from Kullu, Himachal Pradesh, India. A comprehensive qualitative and quantitative description is used to point out the weathering grades of gneissic rock. The mineralogical alterations were determined using thin-section analysis. The petrographic analysis revealed that a major alteration was observed in plagioclase feldspar. The sericitization of plagioclase is mainly noticed with progressive weathering. The quartz grains remain intact and unaltered in fresh and slightly weathered stages while minor fracturing was observed in the moderately weathered stage. The partial transformation of biotite was also observed in moderately weathered gneiss. The chemical composition of these three weathering grades of gneiss was determined using X-ray fluorescence (XRF) analysis. The Plagioclase Index of Alteration (PIA) shows a significant increase with increasing weathering grades that supports the higher alteration of plagioclase during the weathering of gneissic rock of Himachal Pradesh, India.

Rock bolting, rock reinforcement is an ongoing work. Its a necessity in all rock excavation related application areas i.e. in civil infrastrcuture projects, underground mining, open pit mining, tunneling etc. The subject of rock reinforcement, rock bolting is contineoulsy evolving and there has been a lot of new developments has happened over the years e.g. new types of rock bolts, development of rock bolting-reinforcement machines, design methdologies, application process etc. This paper will be specifically focusing on open rock slopes above ground. We have observed an application and methodological process error for applying rock reinforcement, rock bolting on an open rock slopes above ground. The problem is our current practice of installing rock bolts or rock reinforcement on rock slopes above ground is either based on random observation or systematic empirical design formula. In author's view, most of the time existing way of installing rock bolts, rock reinformcement miss to consider the impact of structural geology, geometry, gravational slip surface of rock blocks. In this paper we are presenting a new approach called 'cross-bedding-cross-bolting (CBRB)' for open rock slopes above ground. This new approach and application methodology for open rock slopes above ground mainly consider structural geology, geometry and gravational slip surface of rock blocks. We will present the conceptual theroy as well as the applicaiton methodology of the 'cross-bedding-cross-bolting (CBRB)' approach. The paper will also brifely review and present the existing practices for rock bolting, rock reinforcement, standards followed and application methodology. Our expected out come from this paper is to present a safe and cost efective method for securing open rock slopes above ground. Also, to provide a new approach and corrective measures for application of rock bolt, rock reinforcement for open rock slopes above ground.

Mine tunnels are constructed to offer access for various purposes. The tunnel excavation's primary purpose in this specific mine was to provide ventilation and access to the second-ary orebody. The Malmani dolomites, which contain most natural water resources, directly overlie the Black Reef formation, which is composed of extremely fine to silt quartzite in-terbedded with silt carbonaceous shale. Unexpected ground conditions caused significant delays during the tunnel construction (e.g., fault zone, dykes, laminated carbonaceous shales). After the inception of the fault zone, the tunnel construction could only advance for 9 m. The tunnel construction halted due to the porous ground conditions of the carbo-naceous shale that could not be supported. The layered carbonaceous rock mass presented difficulties due to its geochemical degradation. A suitable feasibility geotechnical program would have aided in the viability of excavating this tunnel within the Malmani dolomites and the possible risk of mining into the water compartments

Rock mass classifications have gained great importance for the last decades for tunneling engineering. Apart from some previous attempts along the XX century, the start of the rock mass classifications can be stated during the 70s with the development of the Rock Mass Rating (RMR) and the Q index, which are regarded at present as the references for most of the technicians, engineers and geologists. More recently, other classifications have been proposed, like the Geological Strength Index (GSI) and the Rock Mass Index (RMi), which are attracting more interest. Unlike in other fields, authors of those rock mass classifications suggested employing more than one system with the aim of capturing different aspects of the rock mass as each of them considers different factors for calculating the value. Therefore, some correlations have been proposed between two of the classifications for obtaining the rate in other system when having one of them. This paper aims to advance in this field and observe if it is feasible to correlate these four rock mass classifications: RMR, Q index, GSI, and RMi. With this aim, the data obtained from the Seberetxe tunnel, with approximately 600 m, in the new segment of the Southern Metropolitan By-Pass of Bilbao, in Spain, was employed. This twin tunnel was excavated by drill and blast in siltstone. Results indicate that the four systems can be correlated with acceptable accuracy in a homogeneous rock type with different weathering. This study shows that correlations can be developed between two of the four rock mass classifications as long as the same rock type is analyzed.

The rock mass is composed of homogeneous and heterogeneous rocks, where the stresses are transmitted with their specific values by: condition, depth and properties of the rocks; each stress has three components with their respective direction and their respective magnitude, being the major principal stress σ1, and the minor principal stresses σ3 and σ2. In the rock massif, stresses are recognized by their influence on underground excavations and must be measured. To measure in situ stresses, the Drillhole Detonation Method (DDM) is proposed, which detects stresses in two processes. 1) Detonation of a drillhole obtaining radial cracks of different length and direction, by joining the ends of the cracks elliptical figures are formed called ellipse of stresses whit their major and minor axes. 2) To evaluate the magnitude of the major stress we use the formula σ1 = FC1 · γ · Z, to evaluate the magnitude of the minor stress we use the formula σ3 = FC3 · k · γ · Z. The Correction Factor (CF) = 0.0056 (measured angle) + 1.003 and the coefficient k is obtained by dividing the length of the horizontal axes by the vertical axes of the ellipse. To obtain the direction and magnitude of σ2 a drilhole is detonated in the direction perpendicular to what has been done to obtain σ1 and σ3. The major axis of the stress ellipse represents σ1. The measurement of stresses by the Drillhole Detonation Method (DDM) is: low cost, calculated at the same time, contributes to optimize the support of underground excavations.

The term discontinuity covers a series of geological structures, very different both in origin and mechanical behavior. It includes the formational planes, like bedding planes and foliation planes, moving fractures and the joints. In order to perform more realistic geomechanical classification and modeling, for the geomechanical rock mass classifications, the term discontinuity should allow to differentiate between the formational structural planes, not related to the stress state, and the joints, that actually depend on the regionally and local stresses. Another inconsistency arises when evaluating roughness, since joints cannot present polished planes, which can apply to moving fractures, in general with different mechanical behaviors from each other. The same is true when applying the term persistence to a formational plane, whose extension is infinite when compared to a recent fracture or a joint. According to recent research results of stability analysis in tunnels and rock slopes, related to the new application criteria for joint formation based on changes in confining forces, this paper proposes the need for a new approach in the application of terminology for the rock mass geomechanical classification and for the geotechnical characterization, eliminating the inconsistencies that arise when applying some definitions indiscriminately to any structure and origin of the plane.

The slope stability analysis, the critical height, the estimation of force on retaining walls or the calculation of the anchor force, requires a mathematical formulation that goes through an optimization process to determine the critical sliding surface. The process consists of the solution of a derivative with respect to the critical surface. The analytical solutions that have been found are based on a simple geometry for a triangular shaped sliding body. In this paper a solution procedure is proposed for cases of any geometry, including complex geometries. A simple numerical method called incremental method, is developed, specially designed for the analysis of stability, thrust or anchorage design by means of a spread-sheet. The methodology allows static or pseudo-static analysis. Several analysis cases are shown and their solution is compared with the results using advanced numerical methods, where an excellent correspondence is demonstrated.

In this investigation, two different cooling techniques (i.e. water- and air-cooling methods) has been used in order to study the influence of different heating-cooling treatments on the physical properties, microstructural characteristics and point load strength of Himalayan granite collect-ed from Sangla valley, Himachal Pradesh. The temperatures for heat treatment were targeted at 100, 300, 400, 500 and 600°C. As a response to thermal treatments, increase in effective po-rosity and increase in damage coefficient occurs which causes exponential decrease in point load strength. It decreases ~74% and ~81% under air-cooling and water cooling respectively after heating of about 600oC with reference to thermally untreated specimens. The microstruc-tural study reveals that the increase in crack density due to thermal treatments induce intra-, in-ter- and trans-granular cracks, at and beyond 300oC onwards and their coalescence with each other at higher temperatures (i.e. ≥ 500oC) under both the thermal treatments contribute to-wards the variation in point load strength of thermally treated granites.

This study investigates the influence of flaw inclination angles on the mechanical response of rock-like specimens with pre-existing flaws under dynamic loading conditions, employing the Discrete Element Method (DEM) software UDEC. Several Split Hopkinson Pressure Bar (SHPB) compression tests were previously conducted on these specimens, each containing a single non-persistent flaw. The study considered two flaw orientations and a single flaw. Earlier experimental investigations revealed that specimens with unfilled flaws exhibited the highest dependency on flaw inclination angle. Notably, the weakest mechanical response for flawed specimens was observed at a 30° flaw orientation, aligning with the shear failure plane of intact specimens. UDEC numerical simulations were performed to further elucidate the experimental findings. The peak stress response of flaw models obtained were less than intact rock models, which matched well with the experimental results. These simulations provided invaluable insights into the dynamic behaviour of rock-like specimens. .

This study addresses the challenge of accurately estimating support forces to mitigate rock slope failures, employing inverse reliability methods like the Performance Measure Approach (PMA) and the Probabilistic Sufficiency Factor (PSF). A comparison with conventional for-ward reliability approaches, such as the Reliability Index Approach (RIA) and the Forward Monte-Carlo Approach (FMC), highlights the advantages of inverse reliability methods. Focusing on wedge-shaped failure scenarios in the Himalayas, the research emphasizes the applicability and effectiveness of the PMA and the PSF. Results indicate that these inverse methods offer improved accuracy and computational efficiency compared to traditional approaches, making them valuable tools for support force estimation in rock slope engineering. Their reduced computational effort enhances practical applicability, positioning them as promising alternatives in the field.

For coal extraction and removal of overburden, blasting is commonly used in most open-pit coal mines. Blasting generates shock energy that crushes the rock initially and then propagates in the form of waves through the surrounding rock. These ground vibrations are detrimental to the safety of the structures that are located in the vicinity. Though the interaction between blast waves and different structures has been extensively studied to safeguard these structures, the specific behaviour of brick masonry structures under blast-induced ground vibrations (BIGV) remains largely unexplored. The influence of BIGV on structural safety necessitates the incorporation of dynamic structural characteristics into safety guidelines to ensure the safeguarding of these structures. In order to investigate the actual behaviour of structures located near the periphery of a mine, a brick masonry wall was modeled in ABAQUS and analysed under the influence of 10 ground vibration time histories from distinct blast events with varying PPV (Peak Particle Velocity) values. A simplified micro modeling approach utilizing the CDP (Concrete Damage Plasticity) model was employed to accurately predict the wall's response. A comparative analysis was conducted, revealing contrary to popular beliefs, that even at very low PPV values, the structure exhibited significant deformations and stresses. Conversely, in some instances with very high PPV values, the structure remained safe. The primary finding underscores that using PPV alone as the determinant of structural safety possesses several limitations. It is imperative to consider the dynamic characteristics of structures in blast designs for a more comprehensive assessment of safety.

Thermal properties describe how heat and temperature behave in a rock. Sandstone is a very common sedimentary rock found in layers formation in coal mining areas. This rock is used for underground backfilling purposes and other applications in mining. For optimizing the heat load in underground mines, the thermal properties of sedimentary rock are very important. We analyze the results of measurements of the thermal properties, porosity and density of sandstone rocks from the Godavari coal basin, Telangana. The thermal properties were measured by the “FOX50” instrument at room temperature (25⁰C). The thermal conductivity of sandstone rocks ranges from 0.65 to 4.38 W/m. K and it is strongly depending on porosity and density. The average range of density of rock samples is 2.28 to 2.50 g/cm³ and average porosity ranges from 6 to 13 %. The results indicate variations in thermal conductivity and diffusivity across different locations, while specific heat appears consistent throughout all regions. The study also investigated how density and porosity affect the thermal properties of rocks. It was found that thermal conductivity increases with density and decreases with porosity. The assessment of thermal conductivity from porosity and density is made possible by the equations that are provided.

Investigating the possible correlation between various measures of rock strength is a common practice in experimental rock mechanics, as the results of relatively simple and economical tests can yield estimates of mechanical properties that would require more sophisticated experimental procedures. For example, the Schmidt hammer test is one of these experimental setups that have been used to indirectly determine the uniaxial compressive strength and the static modulus of elasticity. Nevertheless, this experimental setup has not been extensively used for the indirect determination of other important mechanical properties, such as the point load strength index and the indirect tensile strength obtained from the Brazilian strength test. For this reason, an experimental program was carried out involving at first the direct determination of the Schmidt hardness, the point load strength index, and the Brazilian tensile strength for rock types of various origins outcropped at the southern part of the Attica Peninsula, Greece. Subsequently, the statistical processing of these results was performed via simple regression techniques, while very good relations were established in the form of exponential equations between the Schmidt hardness and both the point load strength index and the Brazilian tensile strength. Our results can be used for preliminary investigations, at least in the study region, and can enrich our knowledge regarding the correlation between the mechanical properties under consideration.

Traditionally employed laboratory tests allow obtaining strength and deformation properties of rocks, such as the uniaxial compressive strength, tensile strength and Young's modulus. Andesite, a pivotal rock in Ecuador, holds significant relevance to civil engineering and mining, yet its geomechanical properties remain inadequately explored. This study delves into the physical, petrographic, and geomechanical characteristics of andesite from the Tungurahua volcanics geological unit in the Real Cordillera of the Ecuadorian Andes. The findings reveal a massive andesite with porphyritic and hyalopilitic textures, boasting high density (2690±36 kg/m³), low porosity (2.11±1.32%), and minimal water absorption (0.31±0.13%). Mechanically, it proves to be a high-strength rock (204 MPa) with nonlinear elastic behavior up to 40% of the maximum strength and an average secant Young's modulus of 35.06±2.47 GPa. These results contribute to enhance our understanding of Andean andesite properties from the Tungurahua volcanics geological unit.

Limit States Design (LSD), which represents an implementation of Reliability Based Design (RBD), is becoming more widely used in geotechnical engineering. Fundamentally this requires a probabilistic characterization of all uncertainties in a given geotechnical engineering problem. Uncertainty is inherent to rock mechanics and rock engineering, and generally stems from factors such as complex geology, vagueness in instability mechanisms and the highly nonlinear mechanical behaviour of rock masses. Such uncertainties are commonly considered using subjective qualitative assessments, SQAs, using what are known as linguistic variables, e.g. a rock mass may be described as being “slightly weathered”. In this paper we demonstrate why SQAs must be considered as ordinal and not metric (i.e. measured) values. We thus show both why it is not possible to directly consider SQAs in a probabilistic setting, and how doing so may lead to significant errors. To overcome this severe limitation of SQAs we apply techniques recently developed in the broader field of imprecise probabilities in engineering analyses. In particular, we examine how SQAs may advantageously be firstly converted into fuzzy numbers and from those into probabilistic variables. An immediate benefit of this approach is that conditional probability can be used to examine situations where both quantitative measurements (e.g. intact rock strength) and SQAs exist. We demonstrate this by constructing a Bayesian network that combines the two characteristics of intact rock strength and degree of weathering, and show how this leads to an interpretation of rock mass condition that directly supports LSD. Using an example from the literature, we conclude with a brief discussion of how such Bayesian networks can be applied to complex rock engineering projects.

This study assesses the influence of petrophysical properties, petrographic features, and depth on capillary imbibition of basalts and lapillistones from the Upper and Middle Vol-canic Complexes of Madeira Island, Portugal, via multivariate statistical analyses and ma-chine learning methods approach. Results demonstrated that the combined effect of mesofabric, porosity, and pore-type connectedness controls capillary imbibition in lapillis-tones and revealed that there is a strong direct relationship between porosity degree and water absorption coefficient by capillarity, C, in all basalts. The tendency for spontaneous imbibition to decrease with increasing depth is as expected in the studied basalts, except for the sections 23.70 27.20 m and 31.5 34.8 m in two different samples where evidence of fracturing episodes was found which leads to a dual-porosity system that favours water absorption. C is proposed as a complementary coefficient in geotechnical studies of vol-canic rocks.

Pore microstructure in rocks regards shape, volume concentration, distribution and connectivity of pores and cracks and has a substantial influence on many macroscopically observed properties such as rock strength and its deformation and fracture behaviour. Cracks in rocks initiate and propagate in response to the applied stress, with the crack path often driven by local distribution of micro-flaws such as cavities, inclusions, fossils, grain boundaries, mineral cleavage planes, and micro-cracks inside the rock. For sedimentary rocks like sandstone, mineralogical composition of interstitial materials between framework grains is also important factor influencing crack parameters. Although these phenomena are generally known and widely described in the macroscale or mesoscale, the microscopic aspects have not been studied very extensively yet. In order to better understand the process which leads from micro-cracks to macroscopic fracturing and thus extends in scale from millimetres to kilometres, the crack initiation, propagation and growth should be studied just in the microscale. In practical terms, knowledge of the failure behaviour of rock mass due to crack propagation is much needed in some important engineering cases, such as, CO₂ sequestration, high-level radioactive waste disposal or stability of underground workings and slopes. In this contribution, the basic outputs of the study of influence of rock microstructure and composition on the fracture toughness of rocks measured by the chevron notch technique and subsequent analysis of cracks geometry using the X-ray computed tomography are presented. Rock samples selected for experiments are representatives of all three major groups of rocks (igneous, sedimentary and metamorphic), from which sediments, namely sandstones, are the most numerous. Four basic crack parameters were investigated on all rock specimens: (1) crack length, (2) crack width, (3) angle of crack deflection from crack initiation zone, and (4) description of crack course. On the basis of laboratory experiments and analyses, the following fundamental conclusions can be made: (1) the value of crack length generally increases with decreasing rock porosity and this trend is most pronounced within the sandstones, (2) the value of crack length generally increases with increasing value of fracture toughness, (3) the value of the crack length of the sandstones increases with a growing degree of silicification of the matrix, (4) in sandstones, the cracks propagation goes preferably throughout the pore space and may be influenced by limonite pigment and (5) in low-porosity crystalline igneous and metamorphic rocks, the cracks spread along the grain boundaries and often also break grains.

Erosion can cause irreparable damage when it occurs on elaborated elements of the cultural heritage. Even very small erosion rates can result in the loss of valuable sculptural details. Rock erodibility is defined as the lithology-based susceptibility to erosion for a given set of environmental conditions. Wind, rain and hail are examples of the main erosion agents affecting the building rocks used in architectural heritage. Human activity can also be the cause of severe erosion processes in rocks. However, the rock suscebility to erosion determines the efficacy of the erosive process and the effective final material loss from the stone surface. Several research lines address the study of rock erodibility in different contexts (fluvial geomorphology, generation of sediments, tunnel construction, etc.) offering a quantitative approach using indices. However, there are very few works focused on the erodibility of rocks in the heritage context. Erosion, weathering and durability are closely related concepts, usually considered synonymous, but they require an individualized study since the effects and causes associated with each process are very different. In this work, a first approach is proposed to the study of the susceptibility to the erosion of four building rocks widely used in the cultural heritage of Spain. Selected rocks are porous limestones and sandstones with porosity higher than 10%. These rock types are frequent in architectural heritage due to both their availability and their high workability. Erosion Susceptibility of studied rocks has been analysed taking into account both petrographic (texture, structure, mineralogy, heterogeneity and anisotropy) and petrophysical (porosity, pore size distribution and mechanical properties) aspects. The resistance to erosion has been determined by means of the laboratory wide wheel abrasion test. Results show that erosion susceptibility is directly correlated with porosity and inversely with mechanical properties. Grain cohesion, friction angle and tensile strength are key parameters to determine erodibility. Mineralogy probably modify the susceptibility to the material loss, being more resistant the quartz-based rocks than the limestones. Future works, however, should verify the results obtained in this approach including new data and new rock types.

This work presents a multiproxy methodology that combines both in-situ outcrop tests and la-boratory methods, for the petrophysical characterization of a potential sandstone CO2 reservoir. Multiproxy methodology was designed to obtain a complete petrophysical and geomechanical characterization including non-conventional techniques in this type of study. Considered sandstone reservoir corresponds to a detrital Buntsandstein facies of the Iberia Chain (central Spain). Specifically, the involved formations are Aranda-Carcalejos (possible reservoir) and Rané (seal). Four main facies were recognized in the stratigraphic sequence, and the petrophysical analysis of each one was carried out. Main petrophysical differences are found between both channel and sheetflood facies, the former being much more porous and permea-ble and less mechanically resistant than the sheetflood facies. The comparative analysis also highlights the strengths and weaknesses of this multiproxy methodology. This work is part of the in-deep geological characterization of a geological complex for CO2 storage potential evaluation.

In the present paper, statistically significant correlations are obtained between sample di-mensions: height H, width W, and length L, on one side, and compressive strength σp and resistance to cutting KL of the clay sample, on the other side. The geomechanical proper-ties of the coal overburden are determined in laboratory conditions. Coal overburden has a predominantly clayey-silty composition, and samples were taken from the Tamnava East-ern Field (Serbia). Laboratory data are analyzed using multiple linear regression. Results obtained indicate the existence of statistically significant correlations between sample sizes and both σp and KL. These correlations are presented in the form of explicit nonlinear mathematical expressions with corresponding diagrams, which enable further quantitative and qualitative interpretation of the mutual interaction of the analyzed geometrical and ge-omechanical properties. Obtained correlations are with high values of the determinism co-efficient (R > 0.9) and low values of standard deviation. Results are further verified using the ANOVA test. Critical values for certain sample dimensions regarding their effect on σp and KL.

The use of 3D slope stability models for assessing risk and opportunity across various time horizons from the life of mine, five-year (5YP), two-year (2YP) and quarterly or three-month (3MP) mine plans is becoming common practice. The goal is to improve mine design reliability, and as an industry, achieve digital twins for mining and slope stability. These improvements are facilitated by faster computing and user-friendly 3D slope stability software as well as in-creasing monitoring instrumentation deployment in open pit mines. This paper investigates the use of Hu coefficients for simulating pore pressures relative to pre-defined phreatic surfaces or groundwater tables to facilitate rapid updates to 3D slope stability models based on updated pore pressure data obtained from a network of vibrating wire piezometers (VWPs). It also dis-cusses pore pressure sensitivity checks for risk management, and the benefits and limitations of this approach.

In 2010 a process was started to stablish international standards on geotechnical instrumentation under the ISO umbrella. General concepts of these standards were published in 2015, the first part on extensometers in 2016, the inclinometers document in 2017, total pressure cells and piezometers were published in 2020 . All these documents have been published in English and French all over the world. In Europe these documents have been published under EN_ISO 18674. Part 8 on the use of load cells to measure load is in the last steps of the approval process and probably Will be published this 2023. The aim of the paper is to show the development and specific role of these standards on the use of geotechnical instrumentation.

The Mediterranean region has witnessed major infrastructure projects in recent decades, with multiple tunnels usually being constructed using NATM (New Austrian Tunneling Method). The essence of this method lies in continuous observation of deformations and geological assessment, allowing for optimization of the tunnel support system. However, the presence of BIM (Block-in-Matrix) rocks implies significant challenges to application of NATM. The BIM rock exhibits chaotic, heterogeneous, and often highly unpredictable geological structure. This makes it impossible to assess the quality of the rock mass using conventional categorization methodologies such as RMR (Rock Mass Rating) or GSI (Geological Strength Index). The challenges of tunneling in BIM rock were encountered in 3,6 km twin tube tunnel Golubinja, which is currently under construction in Bosnia and Herzegovina. Geological profile was initially assumed to consist of medium strong to weak, moderately to highly weathered shale, siltstone and sandstone of Jurassic age. During the construction phase, a significant discrepancy between the predicted geology and the actual conditions was encountered. The actual conditions were characterized by the presence of ophiolite mélange and ophiolithic crust sheets formations leading to a BIM type of material in which the matrix was formed of siliciclastic strata (graphitic phyllite) and blocks were formed of sedimentary and metamorphic rock. The designed short axis distance between the twin tunnels of 25 m led to a strong interaction between the tubes and presented an insurmountable obstacle for tunnel construction. Issues such as collapse of the primary lining and general instability were observed along the extensive sections of the tunnel. The reevaluation of the geological profile, increasing length of the axis distance between the tubes, and implementation of secondary lining as part of the support systems were carried out in order to enable buildability of the tunnel for given conditions. This paper presents key aspects of Golubinja tunnel construction including design approaches and remediation measures to overcome challenging BIM rock conditions.

This work focuses on obtaining and updating an inventory map of active landslides in the region of Sierra de Cartagena-La Union (Spain), a mountainous mining area in southeast Spain, by integrating space-borne InSAR and airborne LiDAR techniques. Ascending and descending Sentinel-1 InSAR datasets were processed to obtain LOS displacements. Moreover, open-access, and non-customized LiDAR point clouds were processed to analyze surface changes and movements. Then, active deformation areas (ADA) maps were semi-automatically derived from the InSAR and LiDAR results by using ADATool. The influence of rainfall was analyzed in detail by means of InSAR time series. The results not only highlight the effectiveness of these two remote sensing techniques (i.e. InSAR and LiDAR) to acquire inventory maps of active landslides in mining zones, but also emphasize the key role of rainfall as an important trigger for landslides.

The rains registered in Leon (Spain) during December 2019 created several problems on the railway platform: Line 130 Venta de Baños-Gijon, Section: La Robla - La Pola de Gordon. Damages were at the P.K. 26+700, where rockfalls happened coming from the rocky front located above the railway track. The rocks that come from the top reached the railway platform. A huge rock of approximately 50 t has exceeded the railway and has stopped on the edge of the town Puente de Alba. There are also some rocks, weighing slightly less than 10 t, which have remained next to the track. A statistical analysis of rockfall was done, to define locations of the mitigation measures and evaluated other practical solutions. Finally choosing the installation of the following systems: Rockfall drape system with TECCO® G65/3 high tensile-strength steel mesh, with horizontal reinforcement ropes and Rockfall barrier, 8 m high and energy absorption capacity of 8,000 kJ.

Wire meshes employed in secured drapery systems are constantly exposed to atmospheric corro-sion, resulting in diminished durability. The durability depends on the aggressiveness of the envi-ronment, unique to each location, and the protection of the wire, which is often poorly defined in projects. The applicable regulations include a classification of different environments (C2, C3, C4, C5, CX) based on their corrosivity levels. The class of environment serves as a technical character-istic to specify the necessary wire protection to ensure the stipulated service life. Steel wire prod-ucts typically have two types of protection: galvanic coatings, delivering electrochemical safeguard, and organic coatings, which create a physical barrier from oxygen. This article examines the perti-nent regulations, analyzing durability tests such as salt spray test and Kesternich test, different alloy alternatives, the projected service life for each environmental classification, and a case history re-garding this topic.

Many excavated weathered rocks have good initial stability but lose geomechanical properties until have behaviors similar to some soils, causing collapse of shoring. This is an analysis of different temporary shoring of excavations and their effectiveness reviewed with monitoring. The analysis reveals the relationship between excavation height and deformations. Likewise, it is observed that the incidence of the excavation stages and geometries has a greater impact on the deformations than the stiffness of the applied support.

Potash mining in Germany is thriving since more than hundred years, however reserves are limited, and many deposits will reach the end of its lifespan within the next decades. A new mining concept has been established to increase the lifespan of the mines and maximize the extraction rate of conventional mined potash deposits. The concept of secondary conventional mining utilizes the reduction of the dimensions of pillars to gain additional high quality crude salt. The supporting effect of the pillars is compensated by backfilling of the mined excavations, supported by a comprehensive long-term monitoring concept. The process of maximizing extraction rate with secondary conventional mining starts with mining of the pillar edges. The developed cavity is backfilled with rock salt (or residual material from the manufacturing). A backfilling grade of 90 % is aspired. In a next step the remaining pillar is excavated, leaving two small pillars at each end, which serve as short-term roof support until the remaining excavation is backfilled. With this procedure pillar after pillar are excavated until the whole mining area is backfilled. In preparation of this mining process rock mechanical investigation is done to proof a save mining process. It contains of a numerical modelling and an observation program. The numerical modelling bases on precise rock mechanical 2D and 3D models. The calculation evaluates possible hazards like pillar or field collapses and predicts the expected rock mechanical behavior. Then latter covers the mining induced effects to convergence and their impacts to barrier integrity as well as surface subsidence. The results show that the stresses in the barriers doesn’t endanger their integrity and the predicted surface subsidence is compatible with their normal use too. Bases on these results a monitoring concept is developed to observe the real rock behavior. It includes the development of convergence in the mining field, the released energy during and after the second mining process as well as the observation of surface subsidence – all bases on advanced observation methods. The comparison of the monitored results with the numerical prediction supplies a robust basis for a save mining process.

A massive rockfall event took place at the very entrance of a steep and large Đerdap Gorge on the Danube River in Eastern Serbia on 12-13^th of December 1974. Detailed engineering-geological examination of the site was undertaken at the time, but the event was never fully reconstructed. With the ascent of new surveying and monitoring technologies, and their greater availability in recent years it became possible to revisit such historical events and completely back-analyze them. Otherwise, the Gorge itself is rather active and constantly hosts minor rockfalls and other instabilities. An important international route passes along its base, where despite preventive and protective measures it remains highly exposed to rockfalls, whereas the river, i.e., the artificial lake itself, and the downstream hydropower plant and dam could be endangered by massive events, like in the 1974 when one third of the Danube River profile was dammed. The said event was triggered in an abandoned limestone quarry named Joc, arguably by several preconditioning factors: draw-down effect due to filling of the Đerdap lake that took place in 1972-1973, adversely oriented caverns subject to progressive failure, disturbed rock by heavy blasting in the past, lubrication along the adversely oriented joint set. In spring 2023, a field campaign targeted at ground surface mapping of the wider area was undertaken using advanced geodetic equipment, comprising of UAV Wintera and Mobile LiDAR scanner Leica Pegasus. The objective was to re-map the entire north face and surrounding topography and reconstruct the rockfall. The resulting point cloud depicts an irregularly jointed rock mass, likely disturbed by heavy blasting. The location of the source area was determined from the available field photos, and suggests that one large feature, placed amidst the slope, about 100 m above the road level was detached. It has been severely deformed and fragmented along the runout, so it has been transformed into a pile of rubble with large sized boulders. Total volume was estimated to 250,000 m³. The reconstruction was performed using a variety of tools, starting from simple 2D and 3D models that implement friction cone theory, to robust 3D models that consider complex geometry of collapsed material and detailed ground relief. Expectedly, robust models were more successful in reconstruction of the event, which was validated on the basis of known runout reach and debris height.

Urban sites in highlands or associated with rocky areas are common, giving them an admirable landscape richness and constituting a relevant part of their identity. However, this uniqueness is closely related to the risk posed by the degradation of rock formations, which generally results in the falling of blocks or, in the most severe cases, in landslides. Only in the past year, this phenomenon has occurred in locations such as Mijas, Almogía or Ardales in Spain. This article takes the example of Alcalá la Real (Jaén) to present a process and analysis model to quantify the geological risk factors in scenarios of rockfalls such as the one that took place in this town, which enables the assessment of the possible actions to be carried out with the aim of reducing these risks. It is important to remark the fact that, in most cases, one of the main premises is that the action should not have a major impact on the landscape. The underlying cause of the study carried out in the aforementioned municipality of Alcalá la Real was the fall of a large block on Calle Utrilla on a Sunday in summertime, as well as the risk of a further landslide affecting the pathways and houses located in the lower part of the hill. Once the block had detached, its fall by gravity put at risk the houses located at a distance of 125 ml. on a slope with a difference in height of 43 metres. The detached block had a volume of about 72 m³ and an estimated weight of 190 tons. The slope from which this block detached is formed by a level of bioclastic calcarenites supported by soft sandstones, sands and wall clays. The state of the outcrop before the instability occurred was conditioned by the strength of the material supporting the calcarenite levels and the fracturing system of the latter. The study considered several actions to be undertaken given the risk that more blocks could detach, quantifying and zoning the risks for each of the proposed actions.

The natural and cut slopes of a segment of the Dharasu-Uttarkashi Roadway (NH-108), located in the Lesser Himalayan Zone in India, have been studied adopting a multi-parametric integrated approach in terms of (1) distribution of magnitude of natural slope (2) engineering geological properties of intact rocks and rock masses, (3) kinematic analysis of slopes, (4) documentation of existing slope failures (5) rock- microstructural implications, (6) multiple geomechanical classifcation of slopes and (6) implications of active tectonics as deciphered from Neotectonic indices. Assessment of stability of slopes based on the combined study of the above parameters has been performed for twelve locations (L1−L12) on the road-cut sections where the slopes mostly have not yet failed. Magnitude of natural slopes overlooking the road section attains peak slope class of 41°−50°. Kinematic analysis characterizes the intact slopes in the above locations to possess conditions of wedge and toppling modes of failure, either in single or as combined. Existing failed slopes conform to combinations of planar, wedge, toppling and shallow circular failures. Rock microstructural study reveals development of strong shear-strength-weakening foliation anisotropy in the phyllites and schistose quartzites of the slopes that evidently serve as avenues of groundwater percolation and seepage and can promote failure along water soaked foliation planes that ‘day-light’ on the road-cut slopes at locations L1, L8 L9 and L10. Based on Geomechanical classifcation systems applied to slopes including Continuous Slope Mass Rating, Q-Slope and Hazard Index, new stability charts have been developed that classify the slopes at each location to be one of the three types: severely unstable, unstable or stable. Based on the new stability charts, road-cut slopes at all twelve locations were found to be unstable and slopes at three locations−L7, L8 and L10 were observed to be severely unstable, particularly hazardous and require immediate mitigation. From the erosional landscape of the study area, using several geomorphometric elements including ruggedness number (R_n), ratio of valley floor-width to valley-height, (V_f), stream length gradient index (S_L) and Hypsometric integral (H_i), an index of neotectonic activity (I_at) over the study area is obtained with an estimated value of 1.50 that indicates high neotectonic activity. Such high value of neotectonic index correlates with the high recent seismicity events documented from the zone containing the study area. Corresponding high neotectonic activity is expected to create steeper slopes due to deeper incisions and would potentially trigger failures in some of the currently stable slopes in the area.

Slope stability analysis is crucial for transportation projects in hilly areas, especially for road or tunnel portals. Various methods exist to assess slope instability, such as field-based, limit equilibrium, Numerical, and rock fall simulation. Among these, the field-based Slope Mass Rating (SMR) method is popular for initial assessments. In this study, a Windows-based Python application was developed to calculate SMR efficiently. The app quickly evaluates slope instability using provided data and allows users to input direct Rock Quality Designation (RQD) or estimate it based on joint spacing. It automatically calculates F1, F2, and F3 factors for all joints and identifies formed wedges due to joint interactions. The app generates detailed reports including joint attributes and ratings, aiding in slope stability interpretation. This user-friendly tool enhances slope stability analysis for project planning and generates technical reports for better project understanding.

Waste dump failures in coal mining pose significant safety risks, necessitating detailed post-failure studies alongside pre-failure deformation study. The post-failure studies evaluate the mobility of the failing mass, measured by parameters like runout length and width (i.e., runout characteristics). The understanding of the mobility of failing mass will help design a buffer zone around an overburden dump to restrict worker and machinery movement. This study, using a laboratory-scale debris flow flume, explores the effect of the composition of overburden dump on runout characteristics and the shape of debris flow fan. The findings of the experimental investigation suggest that while changes in relative proportion of fines and coarse particles (F/C ratio) affect both runout length and width, the effect on the aspect ratio may not show a straight forward pattern. The complex changes in aspect ratio imply that the overall shape of the debris flow fan may not be solely determined by the F/C ratio.

Elastic properties of rocks like Young’s modulus and compressional P-wave velocity are vital for understanding their stress-strain response in mining and rock engineering applications. Traditional methods for determining these properties involve labor-intensive, expensive and time-consuming. To address these challenges, this study proposes a novel predictive method. It utilizes a multi-layer perceptron feed forward neural network (MLP-FFNN) trained on grinding characteristics of ball mill to predict Young’s modulus and compressional P-wave velocity in sedimentary rocks. Laboratory experiments on limestone and dolomite samples generated extensive data, enabling development of prediction models using the proposed MLP-FFNN. The developed models demonstrate high predictive accuracy (R values: 0.952 for E, 0.987 for Vp) in training and good generalization (0.866 for E, 0.9707 for Vp) in testing, along with low Root Mean Squared Error (RMSE) values. These findings underscore the efficacy of neural network models in predicting E and Vp from grinding characteristics of ball mill.

Extraction of coal is done by both opencast and underground method of workings. The amount of overburden removal has increased significantly as the share of opencast coal mining has increased to ensure maximum recovery and greater depths. The accumulation of the removed overburden material as dumps at greater heights for the minimum ground cover area is an important task in the opencast mines due to which the dumps tend to fail. A dump failure can pause mining operations, endanger personnel and damage equipment. In some cases, due to lack of dumping space, the overburden dumps are laid above the underground excavations. The stability of the dumps over the old underground workings is a difficult task because of the stresses that are already developed due to the underground excavation. Therefore, it is paramount to study the stability of the slopes in this zone particularly when there was an old inaccessible extraction present within this zone. In this article, the prediction of stability of overburden dumps above the underground workings are studied by means of underground longwall working dimensions. A two-dimensional finite element analysis method is used in predicting the stability of overburden dump using RS2 software of Rocscience. Strength Reduction Technique is used for determining the factor of safety (FoS) of the overburden dump. From the modelling studies, it is summarized that the stability of the overburden dumps is being affected due to the presence of underground excavation with a vertical deformation of 0.0564m (56.4mm) for the critical strength reduction factor 1.12.

The Grassy Mountain mining project owned by Paramount Gold Nevada Corp. in the state of Oregon, USA has been developed for a Cut and Fill underground mining methodology with cemented backfill (CRF) operation. The present study analyzes the main variables involved in the manufacture and subsequent performance of cemented backfill, through a sampling process involving 12 CRF specimens prepared and tested by MetaRock Lab under the supervision of GMS, in order to obtain the UCS strength values of each one. Thus, 6 CRF specimens with 5% cement and 6 specimens with 7% cement were prepared, which in turn were subdivided into a curing time of 14 and 28 days. From the results of the UCS tests, the variables of cement percentage, sample density and days of curing are directly related to the strength of the CRF, obtaining better performances as these values increase. Finally, based on the benchmarking study, the performance of the CRF samples, according to the mix developed and proposed by GMS for the Grassy Mountain project, is within the expected range. The values for resistance, which is the main indicator to be highlighted, are in accordance with what would be expected according to the characteristics of the mixture, obtaining a maximum resistance of 6.14 MPa.

Due to rapid and extreme climate changes, in mountain and hilly regions infrastructures and people are more often treathened by rockfalls events. Falling boulders can have extremely high speeds, and these events involve a complex pattern of movement (e.g. detachment, fall, rolling, sliding, bouncing, etc) of one or more rock fragments. Rockfall Protection Embankments (RPE) reinforced with geosynthetics proved to be a safe measure for protecting people, structures and infrastructures from rockfall events, designed to absorb even very high impact energy (up to 30,000 kJ). RPEs can be constructed in various shapes and sizes, with different reinforcements (geogrids, geotextiles, geostrips, steel wire meshes, etc.) and facing materials (wrap-around, gabions, tires, etc.). The vast majority of existing RPE structures have been designed with basic approaches, considering dynamics only to a minor extent. The Authors have then developed a new analytical design method which consider the effect of all the variables playing a role in the resistance to penetration on the uphill face and the resistance to extrusion on the downhill face, in order to finally compute approximate yet consistent values of the penetration depth and of the extrusion length; hence the designer can quickly try different solutions and finally select the best combination of design variables which afford to respect all design limits and Factors of Safety. To the Authors’ knowledge, at present this is the only design method for RPEs which allows to take into account all the parameters contributing to the penetration and extrusion resistance, including the type and properties of geosynthetics, the layout and spacing of reinforcement in longitudinal and transversal direction of embankment, the type of facing, the properties of the fill and the geometry of the embankment. A back analysis of full scale tests is used to validate the presented design method.

Cheves Hydropower Project is in the Central Peruvian Andes, N of Lima that generates 825 GWh/year since 2015. The project includes approximately 20 km of tunnels and two caverns. The construction was done mainly in intrusive and the metamorphic rocks; generalized rock burst conditions took place, recording more than 850 stress-events. These events boost themselves in the presence of stiff rocks and geological structures, happening either at the face excavation or behind the face in the reinforced sections. The paper analyses all the factors related to the occurrence of stress-events: overburden, horizontal in situ stress, lithology and stiffness, joint sets and related structures and induced stresses; providing useful criteria, enabling designers to collect data and make some correlations that may be useful for other projects.

The Terradets Gorge is essential in the Catalan linear land infrastructure transport network. It serves as a natural boundary between Noguera and Pallars Jussà, facilitating a vital north-south connection for trade and tourism. In this area roads and railways traverse the gorge, despite facing elevations of rock slopes up to 500 meters. Recent incidents have highlighted their traffic vulnerability to rock falls and debris flows. Both administrations, Roads and Railways of the Catalan Government, have concurred addressing these chal-lenges between 2022 and 2023, enabling the comparison between infrastructure mainte-nance policies and revealing similar solutions for protection and mitigation. The experi-ence underscores the effectiveness of collaborative management in the face of geological risk in priority infrastructure corridors, where both authorities coincide. Sharing resources and strategies not only reinforces efficiency but also promotes cooperation among entities, enhancing resilience against future challenges

This paper presents a procedure of ill-posed problem back analysis of multiple landslides to de-termine the reliable shear strength parameters of rock mass. This procedure includes field in-vestigations, determination of instability mechanism, definition of collapse surface on the rep-resentative section, limit equilibrium stability analysis for variable shear strength properties, and limiting the range of possible answers. This procedure was applied for two individual complex translational-rotational landslides in Jajram Golbini No.07 mine. The investigations indicate the similarity and spatial correlation between the mechanical (shear strength) attributes of sliding surface of both landslides. This provide an opportunity to establish two equations for determination of shear strength parameters. Then, the cohesion and friction angle of rock mass were determined by solving these system of equations. The results of back analysis provide very useful information about shear strength parameters of rock mass and fault that can be ap-plied for reliable redesign of mine slope.

During the 19th century, coal mining in the underground of the Belmez urban area has caused subsidence with small cracks that are balanced by jumps of 1cm/year. Recently, a NW–SE direction cracking with distension of the mining roof terrain has been actived by the drainage of a mining operation and the emptying of two water deposits. A Namurian reverse fault that crosses Belmez on the surface has been reactivated as a dextral shear in the Kimmeric phase. By City Council request, this problem has been studied by comparing the natural tensions in the environment. Using a innovative Seismic Geotechnics, 30 m long NE-SW multi-channel reflection profiles are created for the seismic inversion of guided waves that allow to know the inelastic deformation of the terrain. Beneath this Namurian fault, there are the work-ings of coal layers from 40 m depth. The natural stresses, elastic moduli and friction angle have been obtained with the P and Svertical waves, which have been plotted, together with the inelastic Sradial geostatistics, up to 40 m depth.

In high-resolution research with Seismic Geotechnics, compression waves and three orthogo-nal shears are generated to obtain velocities based on the times of the reflected bands. Using an inverse process, the time domain is transformed into depth, up to 100 m, and distortion models are provided with underground images of natural stresses, friction angle, permeabilities, and elastic and inelastic modules using vertical and radial shear waves. By partitioning the energy of seismic waves at a discontinuity or interface, the initiation of rupture is proposed. Through the impact of energy on the heterogeneous ground surface, constructive waves in phase are reflected at the interface when impedance increases with depth and frequency remains constant. If imped-ance decreases with depth, the partition of the reflected wave presents a longer wavelength and is not constructive; it is out of phase, leading to tension and shear that generate pre-ruptures as deformation increases with the absorption of wave amplitude, resulting in the loss of contact be-tween particles. Results from the sliding model and classical mechanics can be compared; they are also applied in rock compression tests.

The Poggio Baldi Natural Laboratory, jointly managed by Sapienza University of Rome's Department of Earth Sciences and NHAZCA SRL, utilizes cutting-edge instruments like LiDAR, drones, radar, and more to monitor a critically stable rock scarp. It aims to understand connections between rockfalls and factors like geo-structural arrangements, thermal effects, seismic activity, and weather, with the goal of creating an early warning system. Research at the lab focuses on geo-structural characterization, analyzing block failure potential, and assessing rockfall hazards. High-res point cloud data and orthoimages help determine discontinuity orientation and rock block volumes. An innovative algorithm enables pixel-based stability analysis. The study compares data from different sources for analysis suitability and identifies active rockfall zones through 3D change detection. Simulations in these zones evaluate potential hazards. Overall, the lab's multidisciplinary approach using advanced tech enhances our grasp of rock slope dynamics in susceptible hilly regions.

The Scaled Span method is an empirical approach for calculating the stability of mine crown pillars: To determine the stability of the rock bridge between the void and the ground surface. It is a methodology that was born in Canada (Carter, 1988) at the end of the 1980s due to a series of problems and subsidence produced by sinkholes and collapses of shallow abandoned mines. The methodology has been refined over the years and has been applied in numerous countries, such as Canada itself, Austria, Spain, Peru, etc. The database has been increasing and the graph of this method makes it possible to establish both the degree of stability and the possible interventions to be carried out in the upper part of the mine or tunnel (since it has also been applied to shallow tunnels). The methodology uses the rock quality index Q and the dimensions of the void. Scaled Span means that the actual width of the cavity is “scaled” or weighted by other parameters such as rock thickness, length, etc. Volcanic caves or lava tubes are often shallow cavities on which buildings and infrastructures are sometimes built, and many of them are also visited by tourists. It is important for this to carry out an analysis of its stability. The most widely used approximation for the analysis of cave stability is the Q index (Jorda, 2016) but it has many limitations since it only considers geometrically the width of the cavity and not the cover thickness (with the exception of the SRF parameter). cave length, among others. For this reason, the scaled width is a good analysis methodology. In the present investigation, the use by its authors is compiled and extended to various volcanic caves in the Galapagos and Canary Islands, and it is concluded that it is a more realistic methodology than that of only Q-span and that it also provides reasonable protocols to follow for access or impediment to the cave.

In 2021, the Tajogaite volcano on La Palma (Canary Islands, Spain) emitted over 200 million cubic meters of volcanic materials, in the form of lava flows, lapilli and ash. Rebuilding damaged infrastructure, estimated in 1,676 buildings and 73.8 km of roads is a crucial priority. Additionally, it is important to explore potential uses for the products emitted by the volcano. Due to their basaltic nature, volcanic slag, lapilli and ash are suitable for manufacturing building materials such as cement, concrete, blocks or bituminous mixtures. This study focuses on the preparation of concrete tiles using products from the Tajogaite volcano. For this purpose, a laboratory-scale manufacturing procedure for concrete tiles was developed, with the premise of being as sustainable as possible, requiring low energy consumption and minimizing the emissions and waste generation. Various dosages of volcanic material were tested in order to check how it affects the samples performance, as well as to optimize the manufacturing process. The obtained materials were characterized using standard testing methods. Standard UNE-EN 1339 was used as a reference, which specifies the materials, properties, requirements and test methods for cement bound unreinforced concrete paving flagsr. The results of flexural strength tests indicate promising prospects for using the volcanic ash in the production of concrete tiles. However, further research is required to enhance products performance.

The Canary Islands is an archipelago of volcanic origin located in the northern Atlantic Ocean about 100 km from the coast of Africa. Numerous eruptive processes took place during its formation, emitting a large volume of volcanic material. The inhabitants of these islands have known how to take advantage of this resource, and historically, lithologies such as trachytes, basalts, trachybasalts, tuffs, ignimbrites or phonolites have been widely used as building stone. At present, the number of active dimension stone quarries is very small and most of them are concentrated in the islands of Tenerife and Gran Canaria. In the southern part of Tenerife, a pumice tuff known locally as "Canto Blanco" and a group of ignimbrites, with different tonalities, belonging to the lithological unit "Ignimbritas de Arico" are exploited. The extraction of these ignimbrites is carried out by the "Guama" quarry and are marketed under the name "Piedra Chasnera". Fracturing is one of the most important factors for assessing the suitability of a rock mass to provide commercially sized blocks for further processing. The main parameters to consider in a study of this nature are the direction of the joints and their distribution in sets, which define the fracturing pattern, and the spacing which controls the dimensions of the blocks in the rock mass. The main objective of this study is to evaluate the quality of the rock mass of the ignimbrite deposit of the "Guama" quarry. Firstly, given the importance of knowing the joint system to ensure profitable production, the main joint sets in the side wall of the quarry were identified. This evaluation is critical because the quarry owner plans expend the extraction as soon as the upper levels (paleosoil and topsoil) are removed. Secondly, the current exploitation front was analysed by characterising the discontinuities. By measuring the direction and length of the joints and using 3D Block Expert software, the spatial distribution of the fractures was assessed, which allowed to establish the size and volume of the effective blocks, i.e., defined by the natural fracturing.

The identification of rock mass discontinuities and their plane orientation is crucial for determining the characteristics of rock masses. Traditional methods of joint trace surveying can be challenging, time-consuming, and hazardous. However, non-contact measuring techniques offer the advantage of generating accurate objective records of rock masses and enable the measurement of discontinuities from digital surface models and 3D point clouds of outcrops without direct access to the rock mass and associated constraints. An innovative approach for identifying discontinuity planes in rock formations using 3D trace data has been presented in this paper. The concept of curved and straight traces has been introduced, with a curvature index indicating a trace's accuracy in representing its discontinuity plane. Additionally, co-planar traces have been identified by analyzing intersecting straight traces, further contributing to discontinuity plane determination. The methodology's effectiveness has been established through validation using a predefined 3D trace lattice resulting from discontinuity planes with known orientations on a 3D digital rock outcrop model. The methodology has then been applied to analyze 3D trace data from an actual rock outcrop, with successful results. The algorithm enables swift identification of main joint orientations, and this study represents an important advancement in the characterization of rock mass structural properties.

The area of Ollon, Switzerland is regularly subject to different ground instability phenom-enas like landslides due to the nature of its lithology. It is mostly composed of weathered gypsum and anhydrite. This study aims to investigate and characterize the causes of the landslide in Ollon in 2021 by analyzing topographic, historical, geological, and hydrologi-cal data. The last landslide occurred recently on the 1st December 2023.Our analysis ob-serves that the landslide was triggered by geological superficial soil alteration that goes along with a series of rainfalls. The investigation showed that the geological characteristics of the area, including the fast alteration process and steep slopes contributes to a high sus-ceptibility and frequency of landslides in this area.

The use of 3D slope stability models for assessing risk and opportunity across various time horizons from the life of mine, five-year (5YP), two-year (2YP) and quarterly or three-month (3MP) mine plans is becoming common practice. The goal is to improve mine design reliability, and as an industry, achieve digital twins for mining and slope stability. These improvements are facilitated by faster computing and user-friendly 3D slope stability software as well as in-creasing monitoring instrumentation deployment in open pit mines. This paper investigates the use of Hu coefficients for simulating pore pressures relative to pre-defined phreatic surfaces or groundwater tables to facilitate rapid updates to 3D slope stability models based on updated pore pressure data obtained from a network of vibrating wire piezometers (VWPs). It also dis-cusses pore pressure sensitivity checks for risk management, and the benefits and limitations of this approach.

In 2010 a process was started to stablish international standards on geotechnical instrumentation under the ISO umbrella. General concepts of these standards were published in 2015, the first part on extensometers in 2016, the inclinometers document in 2017, total pressure cells and piezometers were published in 2020 . All these documents have been published in English and French all over the world. In Europe these documents have been published under EN_ISO 18674. Part 8 on the use of load cells to measure load is in the last steps of the approval process and probably Will be published this 2023. The aim of the paper is to show the development and specific role of these standards on the use of geotechnical instrumentation.

The Mediterranean region has witnessed major infrastructure projects in recent decades, with multiple tunnels usually being constructed using NATM (New Austrian Tunneling Method). The essence of this method lies in continuous observation of deformations and geological assessment, allowing for optimization of the tunnel support system. However, the presence of BIM (Block-in-Matrix) rocks implies significant challenges to application of NATM. The BIM rock exhibits chaotic, heterogeneous, and often highly unpredictable geological structure. This makes it impossible to assess the quality of the rock mass using conventional categorization methodologies such as RMR (Rock Mass Rating) or GSI (Geological Strength Index). The challenges of tunneling in BIM rock were encountered in 3,6 km twin tube tunnel Golubinja, which is currently under construction in Bosnia and Herzegovina. Geological profile was initially assumed to consist of medium strong to weak, moderately to highly weathered shale, siltstone and sandstone of Jurassic age. During the construction phase, a significant discrepancy between the predicted geology and the actual conditions was encountered. The actual conditions were characterized by the presence of ophiolite mélange and ophiolithic crust sheets formations leading to a BIM type of material in which the matrix was formed of siliciclastic strata (graphitic phyllite) and blocks were formed of sedimentary and metamorphic rock. The designed short axis distance between the twin tunnels of 25 m led to a strong interaction between the tubes and presented an insurmountable obstacle for tunnel construction. Issues such as collapse of the primary lining and general instability were observed along the extensive sections of the tunnel. The reevaluation of the geological profile, increasing length of the axis distance between the tubes, and implementation of secondary lining as part of the support systems were carried out in order to enable buildability of the tunnel for given conditions. This paper presents key aspects of Golubinja tunnel construction including design approaches and remediation measures to overcome challenging BIM rock conditions.

This work focuses on obtaining and updating an inventory map of active landslides in the region of Sierra de Cartagena-La Union (Spain), a mountainous mining area in southeast Spain, by integrating space-borne InSAR and airborne LiDAR techniques. Ascending and descending Sentinel-1 InSAR datasets were processed to obtain LOS displacements. Moreover, open-access, and non-customized LiDAR point clouds were processed to analyze surface changes and movements. Then, active deformation areas (ADA) maps were semi-automatically derived from the InSAR and LiDAR results by using ADATool. The influence of rainfall was analyzed in detail by means of InSAR time series. The results not only highlight the effectiveness of these two remote sensing techniques (i.e. InSAR and LiDAR) to acquire inventory maps of active landslides in mining zones, but also emphasize the key role of rainfall as an important trigger for landslides.

The rains registered in Leon (Spain) during December 2019 created several problems on the railway platform: Line 130 Venta de Baños-Gijon, Section: La Robla - La Pola de Gordon. Damages were at the P.K. 26+700, where rockfalls happened coming from the rocky front located above the railway track. The rocks that come from the top reached the railway platform. A huge rock of approximately 50 t has exceeded the railway and has stopped on the edge of the town Puente de Alba. There are also some rocks, weighing slightly less than 10 t, which have remained next to the track. A statistical analysis of rockfall was done, to define locations of the mitigation measures and evaluated other practical solutions. Finally choosing the installation of the following systems: Rockfall drape system with TECCO® G65/3 high tensile-strength steel mesh, with horizontal reinforcement ropes and Rockfall barrier, 8 m high and energy absorption capacity of 8,000 kJ.

Wire meshes employed in secured drapery systems are constantly exposed to atmospheric corro-sion, resulting in diminished durability. The durability depends on the aggressiveness of the envi-ronment, unique to each location, and the protection of the wire, which is often poorly defined in projects. The applicable regulations include a classification of different environments (C2, C3, C4, C5, CX) based on their corrosivity levels. The class of environment serves as a technical character-istic to specify the necessary wire protection to ensure the stipulated service life. Steel wire prod-ucts typically have two types of protection: galvanic coatings, delivering electrochemical safeguard, and organic coatings, which create a physical barrier from oxygen. This article examines the perti-nent regulations, analyzing durability tests such as salt spray test and Kesternich test, different alloy alternatives, the projected service life for each environmental classification, and a case history re-garding this topic.

Many excavated weathered rocks have good initial stability but lose geomechanical properties until have behaviors similar to some soils, causing collapse of shoring. This is an analysis of different temporary shoring of excavations and their effectiveness reviewed with monitoring. The analysis reveals the relationship between excavation height and deformations. Likewise, it is observed that the incidence of the excavation stages and geometries has a greater impact on the deformations than the stiffness of the applied support.

Potash mining in Germany is thriving since more than hundred years, however reserves are limited, and many deposits will reach the end of its lifespan within the next decades. A new mining concept has been established to increase the lifespan of the mines and maximize the extraction rate of conventional mined potash deposits. The concept of secondary conventional mining utilizes the reduction of the dimensions of pillars to gain additional high quality crude salt. The supporting effect of the pillars is compensated by backfilling of the mined excavations, supported by a comprehensive long-term monitoring concept. The process of maximizing extraction rate with secondary conventional mining starts with mining of the pillar edges. The developed cavity is backfilled with rock salt (or residual material from the manufacturing). A backfilling grade of 90 % is aspired. In a next step the remaining pillar is excavated, leaving two small pillars at each end, which serve as short-term roof support until the remaining excavation is backfilled. With this procedure pillar after pillar are excavated until the whole mining area is backfilled. In preparation of this mining process rock mechanical investigation is done to proof a save mining process. It contains of a numerical modelling and an observation program. The numerical modelling bases on precise rock mechanical 2D and 3D models. The calculation evaluates possible hazards like pillar or field collapses and predicts the expected rock mechanical behavior. Then latter covers the mining induced effects to convergence and their impacts to barrier integrity as well as surface subsidence. The results show that the stresses in the barriers doesn’t endanger their integrity and the predicted surface subsidence is compatible with their normal use too. Bases on these results a monitoring concept is developed to observe the real rock behavior. It includes the development of convergence in the mining field, the released energy during and after the second mining process as well as the observation of surface subsidence – all bases on advanced observation methods. The comparison of the monitored results with the numerical prediction supplies a robust basis for a save mining process.

A massive rockfall event took place at the very entrance of a steep and large Đerdap Gorge on the Danube River in Eastern Serbia on 12-13^th of December 1974. Detailed engineering-geological examination of the site was undertaken at the time, but the event was never fully reconstructed. With the ascent of new surveying and monitoring technologies, and their greater availability in recent years it became possible to revisit such historical events and completely back-analyze them. Otherwise, the Gorge itself is rather active and constantly hosts minor rockfalls and other instabilities. An important international route passes along its base, where despite preventive and protective measures it remains highly exposed to rockfalls, whereas the river, i.e., the artificial lake itself, and the downstream hydropower plant and dam could be endangered by massive events, like in the 1974 when one third of the Danube River profile was dammed. The said event was triggered in an abandoned limestone quarry named Joc, arguably by several preconditioning factors: draw-down effect due to filling of the Đerdap lake that took place in 1972-1973, adversely oriented caverns subject to progressive failure, disturbed rock by heavy blasting in the past, lubrication along the adversely oriented joint set. In spring 2023, a field campaign targeted at ground surface mapping of the wider area was undertaken using advanced geodetic equipment, comprising of UAV Wintera and Mobile LiDAR scanner Leica Pegasus. The objective was to re-map the entire north face and surrounding topography and reconstruct the rockfall. The resulting point cloud depicts an irregularly jointed rock mass, likely disturbed by heavy blasting. The location of the source area was determined from the available field photos, and suggests that one large feature, placed amidst the slope, about 100 m above the road level was detached. It has been severely deformed and fragmented along the runout, so it has been transformed into a pile of rubble with large sized boulders. Total volume was estimated to 250,000 m³. The reconstruction was performed using a variety of tools, starting from simple 2D and 3D models that implement friction cone theory, to robust 3D models that consider complex geometry of collapsed material and detailed ground relief. Expectedly, robust models were more successful in reconstruction of the event, which was validated on the basis of known runout reach and debris height.

Urban sites in highlands or associated with rocky areas are common, giving them an admirable landscape richness and constituting a relevant part of their identity. However, this uniqueness is closely related to the risk posed by the degradation of rock formations, which generally results in the falling of blocks or, in the most severe cases, in landslides. Only in the past year, this phenomenon has occurred in locations such as Mijas, Almogía or Ardales in Spain. This article takes the example of Alcalá la Real (Jaén) to present a process and analysis model to quantify the geological risk factors in scenarios of rockfalls such as the one that took place in this town, which enables the assessment of the possible actions to be carried out with the aim of reducing these risks. It is important to remark the fact that, in most cases, one of the main premises is that the action should not have a major impact on the landscape. The underlying cause of the study carried out in the aforementioned municipality of Alcalá la Real was the fall of a large block on Calle Utrilla on a Sunday in summertime, as well as the risk of a further landslide affecting the pathways and houses located in the lower part of the hill. Once the block had detached, its fall by gravity put at risk the houses located at a distance of 125 ml. on a slope with a difference in height of 43 metres. The detached block had a volume of about 72 m³ and an estimated weight of 190 tons. The slope from which this block detached is formed by a level of bioclastic calcarenites supported by soft sandstones, sands and wall clays. The state of the outcrop before the instability occurred was conditioned by the strength of the material supporting the calcarenite levels and the fracturing system of the latter. The study considered several actions to be undertaken given the risk that more blocks could detach, quantifying and zoning the risks for each of the proposed actions.

The natural and cut slopes of a segment of the Dharasu-Uttarkashi Roadway (NH-108), located in the Lesser Himalayan Zone in India, have been studied adopting a multi-parametric integrated approach in terms of (1) distribution of magnitude of natural slope (2) engineering geological properties of intact rocks and rock masses, (3) kinematic analysis of slopes, (4) documentation of existing slope failures (5) rock- microstructural implications, (6) multiple geomechanical classifcation of slopes and (6) implications of active tectonics as deciphered from Neotectonic indices. Assessment of stability of slopes based on the combined study of the above parameters has been performed for twelve locations (L1−L12) on the road-cut sections where the slopes mostly have not yet failed. Magnitude of natural slopes overlooking the road section attains peak slope class of 41°−50°. Kinematic analysis characterizes the intact slopes in the above locations to possess conditions of wedge and toppling modes of failure, either in single or as combined. Existing failed slopes conform to combinations of planar, wedge, toppling and shallow circular failures. Rock microstructural study reveals development of strong shear-strength-weakening foliation anisotropy in the phyllites and schistose quartzites of the slopes that evidently serve as avenues of groundwater percolation and seepage and can promote failure along water soaked foliation planes that ‘day-light’ on the road-cut slopes at locations L1, L8 L9 and L10. Based on Geomechanical classifcation systems applied to slopes including Continuous Slope Mass Rating, Q-Slope and Hazard Index, new stability charts have been developed that classify the slopes at each location to be one of the three types: severely unstable, unstable or stable. Based on the new stability charts, road-cut slopes at all twelve locations were found to be unstable and slopes at three locations−L7, L8 and L10 were observed to be severely unstable, particularly hazardous and require immediate mitigation. From the erosional landscape of the study area, using several geomorphometric elements including ruggedness number (R_n), ratio of valley floor-width to valley-height, (V_f), stream length gradient index (S_L) and Hypsometric integral (H_i), an index of neotectonic activity (I_at) over the study area is obtained with an estimated value of 1.50 that indicates high neotectonic activity. Such high value of neotectonic index correlates with the high recent seismicity events documented from the zone containing the study area. Corresponding high neotectonic activity is expected to create steeper slopes due to deeper incisions and would potentially trigger failures in some of the currently stable slopes in the area.

Slope stability analysis is crucial for transportation projects in hilly areas, especially for road or tunnel portals. Various methods exist to assess slope instability, such as field-based, limit equilibrium, Numerical, and rock fall simulation. Among these, the field-based Slope Mass Rating (SMR) method is popular for initial assessments. In this study, a Windows-based Python application was developed to calculate SMR efficiently. The app quickly evaluates slope instability using provided data and allows users to input direct Rock Quality Designation (RQD) or estimate it based on joint spacing. It automatically calculates F1, F2, and F3 factors for all joints and identifies formed wedges due to joint interactions. The app generates detailed reports including joint attributes and ratings, aiding in slope stability interpretation. This user-friendly tool enhances slope stability analysis for project planning and generates technical reports for better project understanding.

Waste dump failures in coal mining pose significant safety risks, necessitating detailed post-failure studies alongside pre-failure deformation study. The post-failure studies evaluate the mobility of the failing mass, measured by parameters like runout length and width (i.e., runout characteristics). The understanding of the mobility of failing mass will help design a buffer zone around an overburden dump to restrict worker and machinery movement. This study, using a laboratory-scale debris flow flume, explores the effect of the composition of overburden dump on runout characteristics and the shape of debris flow fan. The findings of the experimental investigation suggest that while changes in relative proportion of fines and coarse particles (F/C ratio) affect both runout length and width, the effect on the aspect ratio may not show a straight forward pattern. The complex changes in aspect ratio imply that the overall shape of the debris flow fan may not be solely determined by the F/C ratio.

Elastic properties of rocks like Young’s modulus and compressional P-wave velocity are vital for understanding their stress-strain response in mining and rock engineering applications. Traditional methods for determining these properties involve labor-intensive, expensive and time-consuming. To address these challenges, this study proposes a novel predictive method. It utilizes a multi-layer perceptron feed forward neural network (MLP-FFNN) trained on grinding characteristics of ball mill to predict Young’s modulus and compressional P-wave velocity in sedimentary rocks. Laboratory experiments on limestone and dolomite samples generated extensive data, enabling development of prediction models using the proposed MLP-FFNN. The developed models demonstrate high predictive accuracy (R values: 0.952 for E, 0.987 for Vp) in training and good generalization (0.866 for E, 0.9707 for Vp) in testing, along with low Root Mean Squared Error (RMSE) values. These findings underscore the efficacy of neural network models in predicting E and Vp from grinding characteristics of ball mill.

Extraction of coal is done by both opencast and underground method of workings. The amount of overburden removal has increased significantly as the share of opencast coal mining has increased to ensure maximum recovery and greater depths. The accumulation of the removed overburden material as dumps at greater heights for the minimum ground cover area is an important task in the opencast mines due to which the dumps tend to fail. A dump failure can pause mining operations, endanger personnel and damage equipment. In some cases, due to lack of dumping space, the overburden dumps are laid above the underground excavations. The stability of the dumps over the old underground workings is a difficult task because of the stresses that are already developed due to the underground excavation. Therefore, it is paramount to study the stability of the slopes in this zone particularly when there was an old inaccessible extraction present within this zone. In this article, the prediction of stability of overburden dumps above the underground workings are studied by means of underground longwall working dimensions. A two-dimensional finite element analysis method is used in predicting the stability of overburden dump using RS2 software of Rocscience. Strength Reduction Technique is used for determining the factor of safety (FoS) of the overburden dump. From the modelling studies, it is summarized that the stability of the overburden dumps is being affected due to the presence of underground excavation with a vertical deformation of 0.0564m (56.4mm) for the critical strength reduction factor 1.12.

The Grassy Mountain mining project owned by Paramount Gold Nevada Corp. in the state of Oregon, USA has been developed for a Cut and Fill underground mining methodology with cemented backfill (CRF) operation. The present study analyzes the main variables involved in the manufacture and subsequent performance of cemented backfill, through a sampling process involving 12 CRF specimens prepared and tested by MetaRock Lab under the supervision of GMS, in order to obtain the UCS strength values of each one. Thus, 6 CRF specimens with 5% cement and 6 specimens with 7% cement were prepared, which in turn were subdivided into a curing time of 14 and 28 days. From the results of the UCS tests, the variables of cement percentage, sample density and days of curing are directly related to the strength of the CRF, obtaining better performances as these values increase. Finally, based on the benchmarking study, the performance of the CRF samples, according to the mix developed and proposed by GMS for the Grassy Mountain project, is within the expected range. The values for resistance, which is the main indicator to be highlighted, are in accordance with what would be expected according to the characteristics of the mixture, obtaining a maximum resistance of 6.14 MPa.

Due to rapid and extreme climate changes, in mountain and hilly regions infrastructures and people are more often treathened by rockfalls events. Falling boulders can have extremely high speeds, and these events involve a complex pattern of movement (e.g. detachment, fall, rolling, sliding, bouncing, etc) of one or more rock fragments. Rockfall Protection Embankments (RPE) reinforced with geosynthetics proved to be a safe measure for protecting people, structures and infrastructures from rockfall events, designed to absorb even very high impact energy (up to 30,000 kJ). RPEs can be constructed in various shapes and sizes, with different reinforcements (geogrids, geotextiles, geostrips, steel wire meshes, etc.) and facing materials (wrap-around, gabions, tires, etc.). The vast majority of existing RPE structures have been designed with basic approaches, considering dynamics only to a minor extent. The Authors have then developed a new analytical design method which consider the effect of all the variables playing a role in the resistance to penetration on the uphill face and the resistance to extrusion on the downhill face, in order to finally compute approximate yet consistent values of the penetration depth and of the extrusion length; hence the designer can quickly try different solutions and finally select the best combination of design variables which afford to respect all design limits and Factors of Safety. To the Authors’ knowledge, at present this is the only design method for RPEs which allows to take into account all the parameters contributing to the penetration and extrusion resistance, including the type and properties of geosynthetics, the layout and spacing of reinforcement in longitudinal and transversal direction of embankment, the type of facing, the properties of the fill and the geometry of the embankment. A back analysis of full scale tests is used to validate the presented design method.

Cheves Hydropower Project is in the Central Peruvian Andes, N of Lima that generates 825 GWh/year since 2015. The project includes approximately 20 km of tunnels and two caverns. The construction was done mainly in intrusive and the metamorphic rocks; generalized rock burst conditions took place, recording more than 850 stress-events. These events boost themselves in the presence of stiff rocks and geological structures, happening either at the face excavation or behind the face in the reinforced sections. The paper analyses all the factors related to the occurrence of stress-events: overburden, horizontal in situ stress, lithology and stiffness, joint sets and related structures and induced stresses; providing useful criteria, enabling designers to collect data and make some correlations that may be useful for other projects.

The Terradets Gorge is essential in the Catalan linear land infrastructure transport network. It serves as a natural boundary between Noguera and Pallars Jussà, facilitating a vital north-south connection for trade and tourism. In this area roads and railways traverse the gorge, despite facing elevations of rock slopes up to 500 meters. Recent incidents have highlighted their traffic vulnerability to rock falls and debris flows. Both administrations, Roads and Railways of the Catalan Government, have concurred addressing these chal-lenges between 2022 and 2023, enabling the comparison between infrastructure mainte-nance policies and revealing similar solutions for protection and mitigation. The experi-ence underscores the effectiveness of collaborative management in the face of geological risk in priority infrastructure corridors, where both authorities coincide. Sharing resources and strategies not only reinforces efficiency but also promotes cooperation among entities, enhancing resilience against future challenges

This paper presents a procedure of ill-posed problem back analysis of multiple landslides to de-termine the reliable shear strength parameters of rock mass. This procedure includes field in-vestigations, determination of instability mechanism, definition of collapse surface on the rep-resentative section, limit equilibrium stability analysis for variable shear strength properties, and limiting the range of possible answers. This procedure was applied for two individual complex translational-rotational landslides in Jajram Golbini No.07 mine. The investigations indicate the similarity and spatial correlation between the mechanical (shear strength) attributes of sliding surface of both landslides. This provide an opportunity to establish two equations for determination of shear strength parameters. Then, the cohesion and friction angle of rock mass were determined by solving these system of equations. The results of back analysis provide very useful information about shear strength parameters of rock mass and fault that can be ap-plied for reliable redesign of mine slope.

During the 19th century, coal mining in the underground of the Belmez urban area has caused subsidence with small cracks that are balanced by jumps of 1cm/year. Recently, a NW–SE direction cracking with distension of the mining roof terrain has been actived by the drainage of a mining operation and the emptying of two water deposits. A Namurian reverse fault that crosses Belmez on the surface has been reactivated as a dextral shear in the Kimmeric phase. By City Council request, this problem has been studied by comparing the natural tensions in the environment. Using a innovative Seismic Geotechnics, 30 m long NE-SW multi-channel reflection profiles are created for the seismic inversion of guided waves that allow to know the inelastic deformation of the terrain. Beneath this Namurian fault, there are the work-ings of coal layers from 40 m depth. The natural stresses, elastic moduli and friction angle have been obtained with the P and Svertical waves, which have been plotted, together with the inelastic Sradial geostatistics, up to 40 m depth.

In high-resolution research with Seismic Geotechnics, compression waves and three orthogo-nal shears are generated to obtain velocities based on the times of the reflected bands. Using an inverse process, the time domain is transformed into depth, up to 100 m, and distortion models are provided with underground images of natural stresses, friction angle, permeabilities, and elastic and inelastic modules using vertical and radial shear waves. By partitioning the energy of seismic waves at a discontinuity or interface, the initiation of rupture is proposed. Through the impact of energy on the heterogeneous ground surface, constructive waves in phase are reflected at the interface when impedance increases with depth and frequency remains constant. If imped-ance decreases with depth, the partition of the reflected wave presents a longer wavelength and is not constructive; it is out of phase, leading to tension and shear that generate pre-ruptures as deformation increases with the absorption of wave amplitude, resulting in the loss of contact be-tween particles. Results from the sliding model and classical mechanics can be compared; they are also applied in rock compression tests.

The Poggio Baldi Natural Laboratory, jointly managed by Sapienza University of Rome's Department of Earth Sciences and NHAZCA SRL, utilizes cutting-edge instruments like LiDAR, drones, radar, and more to monitor a critically stable rock scarp. It aims to understand connections between rockfalls and factors like geo-structural arrangements, thermal effects, seismic activity, and weather, with the goal of creating an early warning system. Research at the lab focuses on geo-structural characterization, analyzing block failure potential, and assessing rockfall hazards. High-res point cloud data and orthoimages help determine discontinuity orientation and rock block volumes. An innovative algorithm enables pixel-based stability analysis. The study compares data from different sources for analysis suitability and identifies active rockfall zones through 3D change detection. Simulations in these zones evaluate potential hazards. Overall, the lab's multidisciplinary approach using advanced tech enhances our grasp of rock slope dynamics in susceptible hilly regions.

The Scaled Span method is an empirical approach for calculating the stability of mine crown pillars: To determine the stability of the rock bridge between the void and the ground surface. It is a methodology that was born in Canada (Carter, 1988) at the end of the 1980s due to a series of problems and subsidence produced by sinkholes and collapses of shallow abandoned mines. The methodology has been refined over the years and has been applied in numerous countries, such as Canada itself, Austria, Spain, Peru, etc. The database has been increasing and the graph of this method makes it possible to establish both the degree of stability and the possible interventions to be carried out in the upper part of the mine or tunnel (since it has also been applied to shallow tunnels). The methodology uses the rock quality index Q and the dimensions of the void. Scaled Span means that the actual width of the cavity is “scaled” or weighted by other parameters such as rock thickness, length, etc. Volcanic caves or lava tubes are often shallow cavities on which buildings and infrastructures are sometimes built, and many of them are also visited by tourists. It is important for this to carry out an analysis of its stability. The most widely used approximation for the analysis of cave stability is the Q index (Jorda, 2016) but it has many limitations since it only considers geometrically the width of the cavity and not the cover thickness (with the exception of the SRF parameter). cave length, among others. For this reason, the scaled width is a good analysis methodology. In the present investigation, the use by its authors is compiled and extended to various volcanic caves in the Galapagos and Canary Islands, and it is concluded that it is a more realistic methodology than that of only Q-span and that it also provides reasonable protocols to follow for access or impediment to the cave.

In 2021, the Tajogaite volcano on La Palma (Canary Islands, Spain) emitted over 200 million cubic meters of volcanic materials, in the form of lava flows, lapilli and ash. Rebuilding damaged infrastructure, estimated in 1,676 buildings and 73.8 km of roads is a crucial priority. Additionally, it is important to explore potential uses for the products emitted by the volcano. Due to their basaltic nature, volcanic slag, lapilli and ash are suitable for manufacturing building materials such as cement, concrete, blocks or bituminous mixtures. This study focuses on the preparation of concrete tiles using products from the Tajogaite volcano. For this purpose, a laboratory-scale manufacturing procedure for concrete tiles was developed, with the premise of being as sustainable as possible, requiring low energy consumption and minimizing the emissions and waste generation. Various dosages of volcanic material were tested in order to check how it affects the samples performance, as well as to optimize the manufacturing process. The obtained materials were characterized using standard testing methods. Standard UNE-EN 1339 was used as a reference, which specifies the materials, properties, requirements and test methods for cement bound unreinforced concrete paving flagsr. The results of flexural strength tests indicate promising prospects for using the volcanic ash in the production of concrete tiles. However, further research is required to enhance products performance.

The Canary Islands is an archipelago of volcanic origin located in the northern Atlantic Ocean about 100 km from the coast of Africa. Numerous eruptive processes took place during its formation, emitting a large volume of volcanic material. The inhabitants of these islands have known how to take advantage of this resource, and historically, lithologies such as trachytes, basalts, trachybasalts, tuffs, ignimbrites or phonolites have been widely used as building stone. At present, the number of active dimension stone quarries is very small and most of them are concentrated in the islands of Tenerife and Gran Canaria. In the southern part of Tenerife, a pumice tuff known locally as "Canto Blanco" and a group of ignimbrites, with different tonalities, belonging to the lithological unit "Ignimbritas de Arico" are exploited. The extraction of these ignimbrites is carried out by the "Guama" quarry and are marketed under the name "Piedra Chasnera". Fracturing is one of the most important factors for assessing the suitability of a rock mass to provide commercially sized blocks for further processing. The main parameters to consider in a study of this nature are the direction of the joints and their distribution in sets, which define the fracturing pattern, and the spacing which controls the dimensions of the blocks in the rock mass. The main objective of this study is to evaluate the quality of the rock mass of the ignimbrite deposit of the "Guama" quarry. Firstly, given the importance of knowing the joint system to ensure profitable production, the main joint sets in the side wall of the quarry were identified. This evaluation is critical because the quarry owner plans expend the extraction as soon as the upper levels (paleosoil and topsoil) are removed. Secondly, the current exploitation front was analysed by characterising the discontinuities. By measuring the direction and length of the joints and using 3D Block Expert software, the spatial distribution of the fractures was assessed, which allowed to establish the size and volume of the effective blocks, i.e., defined by the natural fracturing.

The identification of rock mass discontinuities and their plane orientation is crucial for determining the characteristics of rock masses. Traditional methods of joint trace surveying can be challenging, time-consuming, and hazardous. However, non-contact measuring techniques offer the advantage of generating accurate objective records of rock masses and enable the measurement of discontinuities from digital surface models and 3D point clouds of outcrops without direct access to the rock mass and associated constraints. An innovative approach for identifying discontinuity planes in rock formations using 3D trace data has been presented in this paper. The concept of curved and straight traces has been introduced, with a curvature index indicating a trace's accuracy in representing its discontinuity plane. Additionally, co-planar traces have been identified by analyzing intersecting straight traces, further contributing to discontinuity plane determination. The methodology's effectiveness has been established through validation using a predefined 3D trace lattice resulting from discontinuity planes with known orientations on a 3D digital rock outcrop model. The methodology has then been applied to analyze 3D trace data from an actual rock outcrop, with successful results. The algorithm enables swift identification of main joint orientations, and this study represents an important advancement in the characterization of rock mass structural properties.

The area of Ollon, Switzerland is regularly subject to different ground instability phenom-enas like landslides due to the nature of its lithology. It is mostly composed of weathered gypsum and anhydrite. This study aims to investigate and characterize the causes of the landslide in Ollon in 2021 by analyzing topographic, historical, geological, and hydrologi-cal data. The last landslide occurred recently on the 1st December 2023.Our analysis ob-serves that the landslide was triggered by geological superficial soil alteration that goes along with a series of rainfalls. The investigation showed that the geological characteristics of the area, including the fast alteration process and steep slopes contributes to a high sus-ceptibility and frequency of landslides in this area.