Continuous and stepwise deformation of landslides occur widely during seasonal rainfall and reservoir operation. Therefore, it is important to develop resilient stabilizing structures to ensure that they continue to function even when large deformations occur. In this study, a new anchor cable with a high support and large shear deformation is proposed. The anchor cable primarily consists of free,

The time-dependent deformation of rocks due to stress released by excavation is referred to as squeezing. Accurate evaluation of the squeezing at the design stage can dramatically reduce technical problems and the financial costs of underground structures. Although various methods are presented to predict tunnel squeezing at the preliminary stage, being site-specific and incorporating incomplete databases

To estimate the energy storage and release performances of rock pillars in high stress and gain insights into the prevention and control of rockburst hazards from an energy aspect, several series of single-cyclic loading-unloading uniaxial compression tests with different stress levels were conducted on five types of rocks sampled in standard cylinders and prisms. The concepts of relative energy storage

The analysis of the mechanical properties and the failure mechanism of shale with the effect of temperature are of great significance to the shale gas exploitation. In this paper, triaxial creep mechanical tests and AE monitoring method for shale under step loading were carried out at different temperatures and confining pressures. The classic Poynting-Thomson creep model was improved and the modified

The rocks around wellbores in energy-storage areas are affected by high temperatures and thermal stresses during the extraction of geothermal resources. In this study, the mechanical properties of torus granite samples with different aperture ratios and sizes are experimentally investigated at high temperatures. Further, Acoustic Emission (AE) and Digital Image Correlation (DIC) technology are used

We study the effect of CO2 on the mechanical properties of Morrow Sandstone in Farnsworth Unit oilfield in Texas, where supercritical CO2 is being injected for sequestration and enhanced oil recovery (EOR) applications. We conduct mechanical compression tests with acoustic monitoring and microscratch tests on core samples taken from two wells in the Farnsworth field to quantify the role of CO2 on poroelastic

The objective of the present study is to investigate deformation behavior of anisotropic claystone in relation with material heterogeneity. For this purpose, a set of five triaxial compression tests are performed on samples of Callovo-Oxfordian (COx) claystone under in-situ X-ray micro-tomography monitoring. Complete 3D images of the samples full loading history were recorded and analyzed by digital

Rock burst is one of the most severe dynamic hazards in the underground mining industry, and it is essential to establish a reliable method to achieve accurate prevention and control of it. This paper proposes a comprehensive spatial and temporal rockburst warning method based on the Mann-Kendall trend test (MKT) and spatially smoothed seismicity model, which can evaluate rockburst risk in real-time

The excavation damage zone in rock slopes after drill-and-blast operations is of great significance for assessing the slope stability and design of open pit mines. The traditional method simplifies, the spatial distribution of the damage zone in a slope following blasting is as a single radius distributed, which leads to an inaccurate evaluation of slope stability. Herein, a model coupling the tensile

To reveal the dynamic tensile properties and crack growth law of frozen sandstone under impact loading, dynamic splitting tests (−30–20 °C) with different strain rates were carried out using a split Hopkinson pressure bar (SHPB), and the crack growth process of the specimens was captured using a high-speed camera. The study focused on the analysis of dynamic tensile mechanical properties, energy dissipation

A CHN-BQ method is firstly defined to present the system and connotation of the current Chinese national standard “Standards for Engineering Classification of Rock Mass” GB/T 50,218. The core idea and content of the CHN-BQ method are studied in detail. Based on a qualitative classification of rock masses at the sites of in situ rock deformation and shear strength tests with a total number of 1439 test

The present study investigates the frequency-temperature coupling effects on wave propagation through granite. The pendulum impact test was conducted on the thermally treated long granite bars. The wave propagation coefficients, such as attenuation ratio and wave velocity, were determined for the granite under five groups of high-temperature and six groups of incident waves with different frequencies

Crack initiation and propagation are key scientific questions influencing rock failure. To study crack initiation and propagation during rock failure, CT scanning tests were performed on the sandstone samples. The initiation and propagation stages of sandstone cracks were analysed based on a reconstructed three-dimensional crack structure model. The types of crack initiation and propagation in minerals

The failure mode in rock engineering structures is closely related to the loading mode and loading rate, because of the inertial effects under a wide range of geological conditions. In this work, we propose a modified framework of the phase-field model coupled with plasticity, to investigate the effects of loading rates on the fracture mechanism in elastoplastic rock-like materials. By means of this

The complexity and high frequency of fractures in rock masses make discrete fracture network (DFN) models suffer from burdensome computational consumption when every fracture is explicitly simulated. Meanwhile, the uncertainty in the spatial distribution of fractures also leads to the unnecessary explicit simulation of small fractures to achieve more accurate results. In this study, an equivalent discontinuum

A number of constitutive models have been proposed along time in order to describe the mechanical behavior of rock salt. The basic formulation of these models relies, in general, on the description of deformation mechanisms in the macro or the micro scale. The present note aims at providing a framework for the development of models to describe the creep behavior of rock salts based upon continuum thermodynamics

Time-dependent cracking and brittle creep of rock is fundamental to understanding the long-term evolution and dynamic failure in underground rock engineering. In the present paper, we present a systematic laboratory investigation into the control of single open macrofractures of differing orientations on time-dependent cracking and brittle creep in sandstone using digital image correlation (DIC). For

Understanding the effect that multiscale heterogeneities have on the wave responses of rocks at different frequencies is essential in the interpretation of seismic data. In fact, the behaviors of ultrasonic and seismic waves differ because the experiments involve different spatial scales. Then, a solution is to apply a theory that establishes a relation between the wave properties at different frequency

Rock hazards induced by shear slip along discontinuities are often encountered in deep hard rock excavations. At present, grouted rebar bolts are still the most widely used supporting tools in underground engineering. However, as the in-situ stress increases, the anchoring effect of bolts on rock discontinuities change significantly compared with that in a shallow environment. It is of great significance

An innovative design of a twisted yieldable rock bolt has been developed using the system analysis of conventional rock bolt technology, a thermodynamic approach, and a theory of technical creativity. This bolt consists of one single piece of a metal cylindrical rod having longitudinal feathers that provided its maximal reliability and minimized the cost. The bolt can be driven into a hole with a pneumatic

Classification of rock micro-fractures by acoustic emission (AE) parameters is of great significance for rock health monitoring, instability assessment, and precursor warning. But the criteria have not yet been universally formed for the most commonly used method employing rise angle (RA) and average frequency (AF). We conducted expansion rupturing experiment and elastic wave attenuation experiments

The complexity of the physics of rock blasting is a longstanding modelling challenge. This work presents in detail a three-dimensional, material non-linear finite element based model for wave propagation, combined with a postprocessing procedure to determine the fracture intensity caused by blasting. The rock is described with the Johnson–Holmquist-2 constitutive model, an elastoplastic-damage model

The longwall top coal caving (LTCC) production method, applied by forming a face in the horizontal thickness of the seam and also called horizontal section top coal caving, especially in studies originating from China, is widely used in the production of inclined and thick coal seams. In this production method, in addition to the top coal losses that occur behind the face in the traditional LTCC production

The operation of enhanced geothermal system and geological disposal of radioactive waste typically involve considerable variations in the host rock temperature, and the resulting thermal damage induced by mismatched inter-mineralic expansion could hence modify fundamentally the mechanical rock behaviour. Despite tremendous efforts dedicated to the examination of quasi-static performance after temperature

The application of elastic waves induced through seismic excitation (stimulation) to increase the oil recovery from a hydrocarbon reservoir as an enhanced oil recovery (EOR) technique is currently in its infancy. Seismic stimulation is a cost-effective and efficient method for enhancing oil production from waterflood reservoirs by increasing areal sweep performance and decreasing water cuts, hence

The phase-field damage theory has become a powerful approach to estimate crack propagation via the finite element method (FEM). The sharp crack is smeared into a diffusive fracture propagation zone within a length scale parameter (ℓ). However, the calibration of the phase-field damage model is still difficult, especially for the length scale parameter, which is difficult to directly observe and accurately

To investigate the shale softening behavior induced by water/Carbon dioxide (CO2)-rock interaction, a series of scanning electron microscope (SEM) observation and nanoindentation tests were performed on carbonate-rich shale specimens after high-temperature and high-pressure static soaking treatments. The characteristics of shale surface softening and the evolution of micromechanical properties were

A fractal wave velocity evolution model of the water-bearing coal is constructed to explore the relationship between the complex pore and fissure structure parameters of the water-bearing coal mass and the ultrasonic P-wave velocity, based on the fractal theory and with consideration of the attenuation of ultrasonic waves propagating in the porous media of coal. In addition, experimental study and

Understanding the rock creep behavior is necessary to determine the long-term strength and safety of several geotechnical designs. There are several formulations to study the rock creep; however, most of them do not properly capture the tertiary creep. To overcome such limitation, model improvements have been made and new creep models (e.g., creep models with an associated viscoplastic flow rule) have

Ensuring the high-quality construction of the ST Railway is a top priority for construction organizers and managers. In this paper, a stepwise approach combining bounding box (BB) technology and the Gilbert–Johnson–Keerthi (GJK) algorithm was proposed to determine the intersections between fractures. With the use of a stepwise approach, most of the nonintersecting fracture pairs were excluded, the

The compaction of subsurface chalk during hydrocarbon production leads to technical and societal issues related to well trajectory design, wellbore collapse, seafloor subsidence, and seismic events. Predicting reservoir deformation over time requires well-calibrated constitutive equations to capture the viscoplastic response of chalk according to several parameters including porosity, age, water saturation

A new methodology for the simulation of salt cavity development by dissolution is presented, verified and qualitatively validated by experiments. Starting from an initial cavity, the simulator models the injection of fresh water, natural and forced convection of the brine, and the evolution of the cavity walls due to dissolution. The nonlinear model couples brine mass and momentum conservation (governed

This paper presents the efforts made to design irregular-shaped-heightened-rib/snook based on factor of safety (FOS) during mechanised extraction of already developed coal pillars by continuous miner. In situ monitoring of performance of different sizes of rib/snook with variation in their area, effective-width, width-to-height ratio and height under varying geo-mining conditions are studied comprehensively

To comprehensively understand the differences in mechanical behavior of coal during the mining process at different depths, cyclic triaxial loading and unloading (CTLU) experiments with acoustic emission (AE) monitoring were performed on coal samples collected at 5 depths (300, 600, 700, 850 and 1050 m). The results showed that with increasing depth, the strength and deformation of the coal increased

This study investigates the petrographic changes associated with heat treatment of texturally variant granites from northwest Pakistan. The corresponding effects on the physico-mechanical properties have also been analyzed. Detailed microscopic observations distinguish collected rocks into (i) Alkali feldspar micro-porphyritic variety of Ambela granite (AFG) (ii) coarse grained Malakand granite (MG)

Since coal and petroleum resources are facing depletion, geothermal resources that can be stably mined for a long time are increasingly valued, especially hot dry rock (HDR). However, thermal shock damage of rock is an unavoidable problem in the development of HDR. The effects of thermal shock fatigue on the physical and mechanical properties and heat conduction of limestone are analyzed in this paper

Numerous efforts have been made to determine the five independent elastic constants of transversely isotropic (TI) rocks. Recently, the novel strip load test method combined with the strain inversion method, offering the advantage of requiring only a single-orientation core, was presented (Yim J, Hong S, Lee Y, Min K–B. A novel method to determine five elastic constants of a transversely isotropic

Retreat longwall mining with a double-use entry system has many advantages over other multiple-entry systems including high coal recovery, extra entry excavation, and low risk of coal bursts. The essential of the double-use entry system is to construct a competent solid sidewall to ensure the stability, shape, and profile of the entry during retreating the first longwall face. In this study, a new

Considering the linear energy dissipation law under uniaxial compression, a damage characterization of rocks including the compression energy dissipation coefficient is proposed, which can make the existing damage calculation formula more quantitative. Damage variables of brittle rocks can be directly calculated by using the compression energy dissipation coefficient and the input strain energy of

To calculate the ultimate bearing capacity at the tip of a pile in inclined and highly fractured rocks (GSI ≤ 25), the exponent “a” is incorporated in the resolution approach to generalize the formulation of the original Hoek-Brown failure criterion. This exponent, with values close to 0.5 for good geomechanical qualities of the rock mass, has significantly higher values for GSI less than 25. An analytical

Mechanical properties of rocks under high temperature and high pressure are important for the design and stability analysis of rock mass in deep-buried underground engineering. This study is devoted to investigating the strength and deformation behaviors of granite as well as the thermal degradation mechanism under coupled high-temperature and high-pressure conditions in triaxial compression tests

In this paper, to study the influence of grouting on meso-failure mechanism, acoustic emission (AE) localization technique was used to monitor the micro-cracking during the uniaxial compression tests on single flawed sandstone specimens with or without grouting. Due to the inhomogeneous geometrical structure of the flawed specimens, the mesoscopic damage evolution is also inhomogeneous during the loading

A demonstration area was established on the north slope of the Mahu Depression, Junggar Basin, NW China to carry out the hydrofracturing experiment and a cored well was designed to investigate hydraulic fractures. 345 fractures, comprising HFs, natural fractures, core-handling fractures, and drilling-induced fractures, were harvested from four continuous cores of about 323.19 m that contained mudstone

Understanding the effect of loading rate on the normal deformation characteristics of joints has been an important topic for rock dynamics and rock engineering activities. In this paper, a series of static and quasi-static cyclic compression tests are performed on intact and jointed specimens, to reveal the mechanism of the dynamic normal behaviour of joints. The rate and peak value of the compression

With the increase of burial depth, complex geological environments such as high in-situ stress and high seepage pressure will inevitably affect the generation of zonal disintegration and may induce water inrush disasters during the excavation of the deep tunnel. A true three-dimensional geo-mechanical model test is conducted to study the mechanism of water inrush induced by zonal disintegration under

Constructing high dams in karst valleys remains a challenging issue as karst conduits provide preferential channels for flow through the foundations. The uncertainty of the karst system drastically increases the risk of leakage and hence the difficulty in seepage control at the foundations. This study examined the transient flow behaviors through a karst foundation on which a rockfill dam with a height

To investigate the influence of prefabricated fissure size on the directional propagation law of rock type-I cracks, a simple device for simulating rock crack directional propagation was developed. Subsequently, loading tests for white sandstone samples with different prefabricated fissure lengths and widths were performed. The evolution laws of the deformation field and acoustic emission (AE) were

Tensile fracturing was investigated in this study under a static (10−5) and quasi-static (10−3 and 10−2 S−1) strain rate in three different rock types (marlstone, marble, and hornfels). In addition, the effect of έ on the microscopic properties of the fracture such as the width and tortuosity was investigated by tracing the fracture path under the microscope. The results indicated that by increasing

In this work, a micro-macro mechanics-based constitutive model is developed to describe the compressive failure process of rock. A micromechanics model is first developed based on the conceptual model of a micro cracked spring bond, where two micro parameters with clearly geometric meanings are introduced. By using the micromechanics model, it is possible to reproduce the whole nonlinear failure process

In fractured poroelastic media under high differential stress, the shearing of pre-existing fractures and faults and propagation of wing cracks can be induced by fluid injection. This paper presents a two-dimensional mathematical model and a numerical solution approach for coupling fluid flow with fracture shearing and propagation under hydraulic stimulation by fluid injection. Numerical challenges

The foliation structure and spatial variability are important factors affecting the fracture behavior of slate. According to the statistical analysis of mesostructural information, random slate specimens with the foliation structure are physically reconstructed by coupling a one-dimensional random field with a two-dimensional isotropic random field. A cohesion-based numerical method incorporating the

To investigate the internal moisture migration patterns and mechanical damage characteristics of water-bearing coal, X-ray diffraction (XRD), scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) spectroscopy, acoustic emission (AE) tests, and conventional triaxial tests were carried out on coal samples saturated at different water pressures. The results showed that the saturated water

We propose a new combined detection method for the hidden ground fissures using unmanned aerial vehicle (UAV) with infrared camera and ground-penetrating radar (GPR) and applied it in the panel No. 12203 of the Daliuta coal mine. Subsequently, the extensive UAV aerial photography was taken to obtain the ground surface temperature of the entire longwall panel. The GPR detections along three survey lines

In this paper, the failure mechanism of the cement sheath in gas storage salt caverns under the cyclic internal pressure and cavity shrinkage was explored. First, an elastoplastic damage evolution model for the completion cement was established and further developed as a constitutive equation for numerical calculation. Second, the verification of the model is completed by mechanical tests and numerical

Using ring-shape specimens containing two aligned cracks on the internal surface of the ring, two test configurations subjected to tensile or compressive loads namely (i) diametrically compressed ring (DCR) and (ii) diametrically tensile ring (DTR) specimens were suggested to investigate the full mixed-mode I/II fracture problem. The fracture parameters, including modes I and II stress intensity factors

In this study, based on Mel frequency cepstrum coefficient (MFCC) method, the AE signal characteristics of coal and rock samples were extracted, and the stress state criterion based on signal features was constructed. By integrating back propagation (BP) neural network for deep learning of signal characteristics, the recognition, classification, and prediction of coal and rock materials were realized

Blasting is an important mining operation that usually produce several damaging consequences. Adverse rock fragmentation due to bench blasting is one of them. Hence, analysis of risk level and accurate estimation of particle size distribution of fragment size are of interest. This research developed a new model to simultaneously predict and risk assessment of rock fragmentation using 64 collected data

This paper described an improved multi-layer computational method based on fully coupled thermal-mechanical ordinary state-based peridynamics (OSB-PD), which enables simulating fracturing in granite under coupled thermal-hydraulic effects. Four computational layers, i.e., pre-treatment thermal layer (PTL), mechanical loading layer (MLL), interactive thermal layer (ITL), and hydraulic mechanical layer