A weak interlayer zone (WIZ) is a poor zonal geotechnical system with loose structure, weak mechanical properties, variable thickness, random distribution, and strong extension, that occurs between different rock strata (e.g., tuff and basalt), due to the intense tectonic movement, representing a potential threat to the overall stability of rock masses with WIZs in large underground cavern excavations

From the perspective of spontaneous combustion control in coal mining, this study conducted a progressive axial loading test of broken coal using a self-designed multi-field coupling oxidation test system. The evolutionary characteristics of the bulking factor under different loading conditions of stress, stress–temperature, and stress–moisture were obtained. Subsequently, factors affecting the bulking

The present research focuses on the calculation of the bearing capacity of low-density volcanic Pyroclasts. First, the theoretical basis that define an adequate failure criterion for collapsible rocks based on the parameters that characterize them are developed here. Second, a mathematical characteristic lines method is proposed to resolve the ultimate load of shallow foundation rocks with collapsible

The rapid and accurate measurement of in situ stress fields is one of the essential steps in geological engineering. Indoor acoustic emission tests and the Kaiser effect provide a promising prior peak stress measurement method. This paper aims to qualitatively explore the time delay mechanism of the Kaiser effect under uniaxial compressive stress. Acoustic emission tests were conducted with natural

In cold regions, the anisotropy of sedimentary rocks is modified by repeated frost action, potentially increasing the risks of rock engineering. Hence, a deep understanding of the development of rock anisotropy due to frost action is essential. In this work, two sets of sandstone samples were cored and used in experiments, which contained bedding planes either perpendicular or parallel to the height

Understanding the time-dependent deformation behavior of rock joint is important when evaluating long-term stability of structures built on or in jointed rock masses. This study focuses on the time-dependent strength and deformation of unweathered clean rock joints. First, five grain-scale joint models are established based on Barton’s standard joint profiles using the GBM-TtoF creep material model

Experimental investigations of the effects of elevated temperature on microstructural, mineralogical, physico-mechanical and elastic properties of rocks were carried out to understand the effect of underground coal fire along with thermal damage and failure initiation in Barakar sandstone from the Jharia coalfield, India. Discolouration analysis, petrographic studies, scanning electron microscopy,

The Distinct Element Method (DEM) has gained recent attention to study geotechnical designs with rock-concrete or rock–rock interfaces, such as rock-socketed piles. In this work, 3D DEM models with non-standard contacts laws (the Smooth-Joint and Flat-Joint contact models) are proposed to analyze the response of axially loaded rock-socketed piles with different sockets roughness, since socket roughness

Mining-induced stresses in underground coal mines play a significant role in pillar and ground support design, hence in the safety of mining operations. In the US, Analysis of Longwall Pillar Stability (ALPS) and in Australia, Analysis of Longwall Tailgate Serviceability (ALTS) software are used for designing Longwall coal mine layouts; and in the US, Analysis of Retreat Mining Pillar Stability (ARMPS)

Discontinuous deformation analysis (DDA) method is a discrete element method, presenting a great advantage in modelling deformation and rigid body movements, and it is also an alternative approach for problems involving the fracturing process from continuity to discontinuity if the failure mechanism in DDA is well constituted. This paper presents a new united tensile fracture model (UTFM) for the two-dimensional

The mechanical behaviour of natural, unfilled rock joints is influenced by the interaction between surface roughness and matedness of the contact surfaces. In the field, natural rock joints normally exhibit a mismatch between the contact surfaces, mainly due to different geological processes such as weathering or deformations. Various attempts have been made to estimate how matedness of rock joints

In the current literature, the existence of lithophysae can cause a substantial change in the mechanical properties of tuff rock. However, since the shapes and distributions of the lithophysae are typically irregular and random, exploring the influence of lithophysae existence on the engineering behavior of lithophysae-rich tuff rock using the actual samples is very challenging. Besides, it is almost

Deep rock masses are in true triaxial stress (TTS) fields, and few studies have examined the brittleness evaluation of rock under TTS thus far. In particular, research has not been conducted on the brittleness evaluation index and the effect of TTS. Therefore, based on a summary and analysis of pre-existing brittleness indexes, this paper proposes a brittleness index of rock under TTS that considers

Nanoscale coal deformation affects the geomechanics response of coal structure under external stress conditions. In this study, in situ small-angle neutron scattering (SANS) is used to characterize the evolution of nanopore structures under uniaxial compression on an Illinois coal specimen. Porod invariant mapping is used to estimate apparent porosities at different azimuthal angles. Structure-free

This paper presents a new analytical solution for deep circular tunnels in rock with consideration of disturbed zone, 3D strength and large strain. The rock is assumed to be elastic–brittle–plastic and governed by a 3D Hoek–Brown yield criterion. To take the large displacement around a tunnel into account, the large-strain theory is adopted to determine the displacement of rock in the plastic zone

True triaxial short-term and long-term tests were conducted on three different types of hard rocks, namely, marble, basalt and granite. During true triaxial long-term creep tests, the crack evolution information was collected by using an acoustic emission system. The micro-structures before and after creep tests were analysed by scanning electron microscopy and polarising microscopy. The time-dependent

It is significant to conduct anchorage on the non-persistent jointed rock mass by bolts to inhabit the unstable fracture evolution of rock engineering. In this research, a series of experiments are done on 70 specimens to investigate the effect of anchorage method on strength and deformation behavior of a non-persistent jointed rock mass. First, based on the stress–strain curves of anchorage jointed

This paper presents a novel petrophysical experiment for measuring the 3D permeability tensor at reservoir conditions in fractured vuggy carbonate rock. The permeability variation with confining pressure is demonstrated through the experimental investigation; the permeability ellipse plots show the decrease of permeability, as a function of the increase in effective stress. The experiment was developed

The rate-dependent mechanism is analyzed for frictional contact between a blunt tool and a fluid-infiltrated porous rock under pressurized condition. The dimensional analysis is adopted to derive a dimensionless number \(\lambda\) that predominantly governs the rate-dependent mechanism from pore pressure diffusion. The governing nature of \(\lambda\) is analyzed by finite element modeling using the

Steel shots are suitable for abrasive waterjet rock cutting and recycling because of the high hardness and magnetic properties of steel. This study evaluated the rock-cutting performance and recycling characteristics of steel shot waterjet. The rock-cutting responses of steel shot and garnet were compared at the same waterjet conditions. The used steel shot was collected and the particle-size changes

Aiming at the fact that discontinuities in rock mass exhibit different orientations, uniaxial compression tests of resin specimens containing a strike-inconsistent fissure pair were carried out to investigate the failure behaviour of the ligaments. Combined with computerized tomography scanning technology, cracking behaviour and ligament failure pattern were revealed. The failure characteristics and

An abrasive air jet, which is sufficiently powerful to break rock, has significant potential in the field of assisted rock breaking, such as assistive tunnel excavation using a tunnel boring machine. To make its application more efficient and beneficial, a clear and definite erosion mechanism of an abrasive air jet is necessary. However, the present erosion mechanisms of an abrasive air jet have mostly

Dynamic fragmentation is one of the primary fracture types for rock mass in rock engineering. The dynamic fragmentation process and dynamic fragment size characteristics are important for the fragmentation optimization in field. Most researchers studied the fragmentation forming process via dynamic compression test using the traditional split Hopkinson pressure bar (SHPB) system, in which the multiple

Pillars are often reserved asymmetrically in the mining process. The roof deflection curve under non-equal span conditions of adjacent stopes is derived by considering the roof-pillar system as a rock beam-pillar model. The pillar instability condition under asymmetric mining is determined based on instability theory and cusp catastrophe theory. Pillar burst represents the equilibrium stability of

Rock bolts are one of the main measures used to reinforce unstable blocks in a rock mass. The embedment length of fully grouted bolts in the stable and competent rock stratum behind the unstable rock blocks is an important parameter in determining overall bolt length. It is required that the bolt section in the stable stratum must be longer than the critical embedment length to ensure the bolt will

This paper presents a newly observed phenomenon of upscaling of rocks’ properties using big data nanoindentation and analytics involving Gaussian mixture modeling (GMM), leading to characterizing the cross-scale mechanical properties of four shales and one sandstone. A large number (i.e., ~ 500) of statistical indentation measurements to depths of 6–8 μm were performed on each rock, resulting in continuous

Many soluble rocks will dissolve when in contact with fluid such as water. This transformation of rock solid into flowing fluid may trigger the creation of cavities which may further lead to either smooth subsidence or sudden collapse of land surface. Dissolution phenomenon can be of natural or human origin. This paper deals with the problem of the dissolution of underground soluble rocks and the geomechanical

Rock brittleness is an essential mechanical property, which plays a significant role in rock classifications and rockburst risk evaluations. To overcome the problems associated with the traditional brittleness indexes not comprehensively charaterizing the rock strength and deformation behaviors, this study systematically summarized the existing rock brittleness indexes. Then, a novel brittleness index

This paper proposes a method for solving the stress field of a deep circular tunnel affected by an unsteady temperature field. The tunnel is idealized as an infinite domain problem, and the solution of the unsteady temperature field can be regarded as solving the temperature field in the infinite domain under the first type of boundary conditions. The temperature field distribution inside the tunnel

The mechanical behavior and permeability evolution of saturated hard rock are significantly important to the stability and safety of super-high arch dams. A series of triaxial compression tests were conducted on amygdaloidal basalt under different pore pressures. Based on the experimental results, a micromechanical-based elastoplastic damage model is proposed for such saturated hard rock. The hydromechanical

Ultrasonic studies have been used as low-cost, quickly updated, non-destructive techniques in geology and geo-technique. Conventional geophysical operations that allow measurements of wave velocity in rock mass are costly. In this study, we sought a strategy for calculation of wave velocity in rock mass without these field operations. The velocity of a wave in rock mass is a function of two major factors:

The article Mechanical and Volumetric Fracturing Behaviour of Three-Dimensional Printing Rock-like Samples.

This paper proposes a unified constitutive model for rock based on the newly modified generalized Zhang-Zhu (GZZ) criterion. The constitutive model adopts a non-associated plastic flow rule and a continuous potential function that takes the three effective principal stresses into account. To reflect strain-softening, strain-hardening, and elastic-perfectly plastic behavior of rock in a unified way

Many macrocracks are usually generated during the fracturing of rocks. Elucidating the spatial distribution of cracks provides the basis for understanding crack nucleation and fracture formation in rock mechanics. Considering either a single microcrack or all the microcracks provides a limited interpretation of rock mass failure that is often induced by different macrocracks. Here we recognize macrocracks

Accurate evaluation of the influence range of borehole hydraulic fracturing (HF) in coal seam is crucial for optimizing the design scheme of HF. In this study, we adopted the microseismic (MS) monitoring technology to monitor and characterize the spatial shape of cracks caused by borehole HF in coal seam in an underground coal mine. And we also tested and analyzed the stress and moisture content changes

Crack velocity, gas ejection, and stress waves play an important role in determining delay time, designing a blast and understanding the mechanism of rock fragmentation by blasting. In this paper, the emerging times of the earliest cracks and gas ejection on the lateral surfaces of cylindrical granite specimens with a diameter of 240 mm and a length of 300 mm were determined by high-speed photography

This work aims at investigating the fracture evolution and energy characteristics of marble subjected to fatigue cyclic loading and confining pressure unloading (FC-CPU) conditions. Although rocks under separated fatigue cyclic loading and triaxial unloading conditions have been well studied, little is known about the dependence of the fatigue damage accumulation on the subsequent confining pressure

The Neelum–Jhelum Hydropower Project, commissioned in April 2018 and located in the Azad Kashmir region of northeast Pakistan, is one of the most challenging and technically complex projects in the region. The project’s 28.6 km headrace tunnels are constructed in a highly mountainous region with relatively complex geology that includes various sedimentary rocks of Murree formation. The hydro-mechanical

The mechanical behavior of rock under cyclic loading is quite complicated compared to monotonic loading or unloading conditions. The triaxial cyclic loading and unloading testing of rock specimens under 6 confining pressures (σ3) was carried out through the MTS 815 rock mechanics testing system, to explore the strength, deformation, and expansion characteristics of the rock specimens. The stress–strain

The freezing method is an effective approach for constructing coal mine shafts through water-rich soft rock strata. The frozen wall produced by this technique stops the movement of water and offers temporary support, ensuring the safety and stability of the shaft working face. However, most frozen rock masses generally comprise ice-filled flaws and frozen intact rock. A frozen fissured rock mass undergoing

Fracking is widely applied to enhance shale gas mining, and insight into the fracture behaviors of shale rocks is important. To characterize the fracture properties of Lower Silurian Longmaxi shale, a chevron-notched deep beam specimen, which inherits the advantages of notched deep beam and chevron-notched specimens, is introduced, and several three-point bend tests were conducted on the Longmaxi shale

This paper introduces a new high-pressure servo true triaxial rockburst experimental apparatus that can realize multi-face rapid unloading in the horizontal direction. The apparatus is used to simulate different types of strain burst phenomena in deep underground engineering, such as those at roadways, roadway intersections, and pillars with three and four free faces. In the research and development

This study investigates the effects of thermal treatment and exposure time on the physico-mechanical properties related to the mineralogical and structural changes of clayey rocks at temperatures of up to 1000 °C. Vitric-crystal tuffs were studied because they show different engineering behavior than most rocks at high temperatures. The samples were heated at the rate of 10 °C/min, exposed to the desired

The D-shaped cross section is a commonly used tunnel cross section in underground engineering. To simulate the failure process of a D-shaped hole under deep three-dimensional (3D) high-stress conditions, true-triaxial tests were conducted on cubic granite specimens with a through D-shaped hole, and the failure process of the hole sidewall was recorded in real time. Results show that the spalling failure

Crack propagation can gradually reduce the strength of the rock and eventually result in rock failure. Coupling effect of stress and seepage in fracture could accelerate the rock failure process. In this work, a set of water sealing device is developed to apply different fluid pressures in the pre-existing fracture in specimens made of rock-like material. We have carried out uniaxial compression tests

Shale formations are the main source of borehole stability problems during drilling operations. Suboptimal predictions of borehole failure may partly be caused by neglecting the anisotropic nature of shales: Conventional wellbore stability analysis is based on borehole stresses computed from isotropic linear elasticity (Kirsch solution) with the assumption of no induced pore pressure. This is very

We intercompare highly constrained physical experiments with a three-dimensional bonded-particle discrete element model. The models incorporate a single inclined rough joint at various inclinations to simulate the mechanical response of fractured-rock from micro-scale cracking through crack-coalescence and culminating in macro-scale rupture. This approach combines the scanned 3D surface morphology

The effect of high temperatures up to 800 °C on the physical and mechanical characteristics and fracturing behaviour of Beishan granite is experimentally studied with a combination of acoustic emission (AE), digital image correlation (DIC) and optical microscope observations. The experimental results show that the responses of the P-wave velocity, the effective porosity, Young’s modulus, and the uniaxial

In this investigation, two different varieties of ‘Prada’ limestones were studied: a dark grey texture, bearing quartz, clay minerals, organic matter and pyrites, and a light grey texture with little or no presence of such components. We have observed two effects of different intensity when heating the dark texture from 400 °C: (1) the explosion of certain samples and (2) greater thermal damage than

The present study aimed to quantify the thermally induced deformation and the associated evolution of permeability in Blaubeuren limestone, an outcrop analogue of the Upper Jurassic (Malm) carbonate formation, providing references for hydro-thermo-mechanical responses of the reservoir rock to temperature changes within future enhanced geothermal systems as located in the Southern German Molasse Basin

In tunneling, rock mass grouting is a method applied to reduce water ingress. Grouting is influenced by rock mass conditions, especially apertures, frequency, and continuation of fracturing. These rock mass conditions can partly be determined by rock mass classification systems. At the Stockholm bypass, the Measurement While Drilling (MWD) Fracturing Index was applied to characterize the rock mass

In this study, a new strain burst test system was used to conduct two types of strain burst experiments by rapidly unloading single and double faces (in one direction), to simulate the strain burst occurring in surrounding rock of tunnel or double tunnel faces during the opposite tunneling. A high-speed image recording system and an acoustic emission system were used to monitor the failure process

Electric potential (EP) signals are detected when coal or rock materials are subjected to mechanical loading. Such signals are attributed to the generation and accumulation of free charges under externally applied loads. Due to the excellent correlation between EP and damage evolution, EP methods have great potential in rock mass structural engineering damage monitoring. To systematically study the

In the framework of a deep geological radioactive waste disposal in France, the hydromechanical properties of the designated host rock, the Callovo-Oxfordian claystone (COx), are investigated in laboratory tests. Experiments presented in this study are carried out to determine several coefficients required within a transversely isotropic material model. They include isotropic compression tests, pore

The Callovo-Oxfordian (COx) claystone is considered as a candidate host rock for a deep geological radioactive waste repository in France. Due to the exothermic waste packages, the rock is expected to be submitted to temperatures up to 90 °C. The temperature rise induces deformations of the host rock, together with an increase in pore pressures, involving complex thermo-hydro-mechanical (THM) couplings

The permeability evolution of fractal-based two-dimensional discrete fracture networks (DFNs) during shearing under constant normal stiffness (CNS) boundary conditions is numerically modeled and analyzed based on a fully coupled hydromechanical (HM) model. The effects of fractal dimension, boundary normal stiffness and hydraulic pressure on the evolutions of mechanical behaviors, aperture distributions

This paper presents an experimental procedure for the characterization of the granitic rocks on a Mars-like environment. To gain a better understanding of the drilling conditions on Mars, the dynamic tensile behavior of the two granitic rocks was studied using the Brazilian disc test and a Split Hopkinson Pressure Bar. The room temperature tests were performed on the specimens, which had gone through

The geomechanical integrity of shale overburden is a highly significant geological risk factor for a range of engineering and energy-related applications including CO\(_2\) storage and unconventional hydrocarbon production. This paper aims to provide a comprehensive set of high-quality nano- and micro-mechanical data on shale samples to better constrain the macroscopic mechanical properties that result

Long-term exposure to chemical solutions can change the mineral composition and microstructure and may seriously affect the physical and mechanical properties of rocks. Therefore, to clarify the effects of long-term exposure and types of acids on the mechanical properties of rocks, and to develop the constitutive model of acid-immersed rocks, uniaxial compression tests were carried out on acid-immersed

An improved understanding of pillar strength and pillar failure mechanisms is required to optimize tabular mine layout designs. The paper describes the application of a limit equilibrium model for pillar failure analysis. It is shown that the model is capable of reproducing a hardening or softening response for uniformly compressed strip or square pillars. The stress–strain behavior depends on three