Mechanical Properties Of Rock Mass Research Articles

Analysis of fracture deformation field and energy evolution of granite after high confining pressure cyclic load pre-damage.

Considering the recent developments of deep mining, investigating the rock properties under high ground stress periodic load is highly demanded. Studies show that these characteristics are important factors affecting the long-term steadiness of rock. However, the mechanical properties of rock mass without macro failure after cyclic load should be studied. In the present study, granite in a mine is considered as the research object. A rock pre-damage experiment is conducted with the same cycles under different confining pressures and constant cycle upper and lower limit loads. The pre-damaged rock sample is subjected to a uniaxial compression test, and a high-speed charge couple device camera is used to record the speckle field image of the sample surface during the whole loading process. The digital speckle techniques are used to analyse the image of the pre-damaged sample, the deformation field of the specimen surface, the displacement dislocation value of the localized deformation area and the deformation energy value of the specimen surface. The results show that for the same cycle times, the confining pressure is less than 80 MPa, which has a weakening effect on the rock's axial strength. As the confining pressure approaches 120 MPa, the pre-damaged rock uniaxial peak strength increases. The characteristics of displacement dislocation energy evolution of the localized deformation bound are divided into three stages (pre-peak stage, peak point and post-peak stage). After pre-damage under the same cycle times and different confining pressure conditions, the deformation field evolution of rock is relatively consistent.

Improvement of operational exploration and mining safety using the shear-wave reflection method of mine seismology

During the whole life of mines, the geological survey departments are faced with the critical objectives of operational exploration. These objectives are sometimes impossible to be met adequately without geophysics. Neutrality of geophysical studies is often below the desired level. The shear-wave reflection method of mine seismology, with separation of reflections, which is developed by the present authors, allows: investigating the shape, thickness and dip angles of geologic beds and ore bodies, detecting geological discontinuities such as faults, joints and cavities, as well as determining physical and mechanical properties of rocks. The capacity of the shear-wave reflection method with separation of reflections is described in a case-study of the Upper Kama Potash Salt Deposit. The seismic tests were carried out in a few underground excavations. The developed method in the test conditions is accurate to the first meters at a spacing more than 300 m. Accordingly, it is possible to study the whole thickness of the salt strata in the Upper Kama Deposit, from the salt table to the anhydrous clay roof, specifically, to assess the structure and composition of the waterproof strata, to identify mine-threatening geological discontinuities, and to build the model of physical and mechanical properties of rock mass. Introduction of the newly developed method can greatly enhance efficiency of actual operational exploration. The method has yielded the best results during or immediately after heading of permanent and development openings. Considering similarity of surface and underground mineral mining in terms of access to solid rocks, it is expected to have the same outcomes in open pit mines.

Effect of unloading in two directions on the formation of a deep-seated flexural toppling failure

A deep-seated flexural toppling failure of rock masses is located on the right bank upstream of the Lancang River, Southwest China. The rock masses unloaded intensely in two directions and formed intense toppled rock masses with lengths and widths of 1200 m and 950 m, respectively, and volumes over 1.5 × 108 m3. The toppled rock masses could be classified into three grades from surface to deep rock masses: strongly, moderately and weakly toppled rock masses. The strong unloading of rock masses during the rapid downcutting process of rivers was one of the main external factors that induced deep-seated toppling failure. The mechanism could be summarized as follows: intense unloading destroyed the structure of rock masses and weakened the mechanical properties of rock masses by forming many unloading cracks in rock masses; additionally, the stress field of the slope was further redistributed and a stress relaxation zone formed in the strong unloading zone. Then, the stresses of rock masses in the relaxation zone were dominated by gravity, and the deep-seated toppling failure formed in the strongly unloaded rock masses under the action of gravity.

Profiles of Near‐Surface Rock Mass Strength Across Gradients in Burial, Erosion, and Time

AbstractRock mass strength is recognized as an important control on landscape morphology and evolution. However, the controls on rock strength in mountainous topography remain poorly characterized, in part because strength remains challenging to quantify at spatial scales relevant to geomorphology. Here we quantify the mechanical properties of rock masses using subsurface S‐wave velocities, Schmidt hammer hardness values, and Geological Strength Index (GSI) observations. We produce shallow depth profiles of rock mass shear strength using intact rock hardness as measured from a Schmidt hammer, and assessment of the structure and surface conditions of fractures using GSI. We apply these techniques to the Western Transverse Ranges, southern California, USA, where gradients in stratigraphic age and erosion rate allow us to evaluate our methodology. We resolve strength differences of 200 kPa to ∼5 MPa that appear to be related to diagenetic changes associated with the maximum burial depth of young clastic sedimentary rocks. For rocks of the same lithologic type, stratigraphic age, and inferred burial histories, we resolve smaller differences in strength (300 kPa–1.5 MPa) that appear to be positively correlated with mean erosion rates. We suggest that the increase in strength with increasing erosion rate reflects decreased residence time in the weathering zone for ranges experiencing faster fault slip rates. These findings demonstrate up to an order of magnitude variability in strength with respect to burial, erosion, and time for lithologically similar rocks. As such, lithology alone is unlikely to adequately capture the role of rock strength in landscape evolution.

Taking into account the spatial variability of the physical and mechanical properties of a hydraulic dump when flushing it

Introduction. Slope stability analysis reliability depends on the level of schematizing the results of engineering-geological survey, hydrogeological monitoring, electrical sounding, and mine surveying data generalization. In order to improve the stability analysis accuracy, it is relevant to use the geomechanical models, which take into account the spatial variability of the adjacent rock mass physical and mechanical properties, with further search for the most hazardous section in the plan. Research aim is to substantiate the relevance of slopes physical and mechanical monitoring by the methods of downhole control and further stability analysis with the use of the geological and geophysical models. Methodology includes the search for the most hazardous section of the rock mass by the ratio of the shearing and restraining forces within the limits of the established zones characterized by the variability of physical and mechanical properties. Results. As a result of generalizing the databases of the engineering and geological study, hydrogeological monitoring, electrical sounding and mine surveying, the volumetric geological and geophysical models were built of the technogenic massif formed at the dump, as well as the slopes of the hydraulic overburden face, represented by the three-level fill of dry overburden. Test areas stability has been analyzed for the actual position, and the comparative analysis of the results was made. Conclusions. When building volumetric geological and geophysical models of man-made rock masses formed at the areas of filled hydraulic waste diposals, in addition to the results of the traditional survey measurements and direct engineering and geological study, it is important to create informative databases on spatial and temporal variations of physical and mechanical properties of alluvial rock conditioned by their fluid loss and consolidation, which with in details at cross hole intervals may be obtained based on the statistical dependences on electrical conductive properties variation by the methods of electrical sounding or tomography; and when making enclosing embankments (bridges) of dry rocks – information about excess pore pressure under these facilities. When using the hydromechanized method for the alluvial rocks, relatively homogeneous in strength properties, the hydraulic overburden face slope stability is determined to the greatest extent by the absolute values of the accumulated strength indicators in the mined area and the unfavorable combination of the edge shape (the presence of protruding sections and face unevenness in the plan) with the entry height. The established range of the stability coefficient was n = 1.03–3.76. The stability of the enclosing structures made of dry rock to the greatest extent depends on weak alluvial layer depth and thickness and the absolute value of excess pore pressure in this layer. The established range of stability coefficient variation for this rock mass section is much narrower and amounted to n = 1.29–1.59.

Physical and mechanical properties of placers and rocks in the Rakovsky and Bolotny stream channels in the Vedugin gold occurrence area

The information on the rock mass behavior in the course of mineral mining is of vital necessity for exploration and mining companies. In engineering decision-making as well as for the prevention of possible difficulties, it is required to have the most comprehensive data on physical and mechanical properties of rock masses. The aim of this study is determination of physical and mechanical properties of placer rocks in the Rakovsky and Bolotny stream channels in the Vedugin gold occurrence area, as well as assessment of elasticity and brittleness of ore and rocks to define their susceptibility to rockbursting. It is found that bedding rocks in Rakovsky and Bolotny placers down to a depth of 87 m below ground surface are rockburst-non-hazardous. The research findings are usable in elaboration of project documentation for mining Rakovsky and Bolotny placers, as well as in selection of technologies for supporting rock mass and for actual mining of placer reserves. In the latter case, it is possible to make reasonable decisions on support design and geotechnology parameters so that to combine mining safety with the quality of mineral extraction as early as the project design. It is recommended that Burkandya company undertakes continuous monitoring and prediction of rockburst hazard as mining is advanced to deeper levels.

Sub-level Classification and Prediction System of Fully Weathered Red Sandstone Rock Mass Based on Physical Property Indices

This paper intends to obtain a sub-level classification of fully weathered red sandstone rock mass during the Cretaceous period based on physical property indices. An automatic prediction system for mechanical properties of rock mass is also established in which the values of rock mass grade and mechanical properties can be returned when physical indices are given. In this study, water content, relative compaction, and fine content, which are relatively easy to measure on tunnel sites, are selected as physical property indices, while cohesion, internal friction angle, and compression modulus, which affect mechanical strength, are taken as mechanical indices. For the convenience of analysis, rock mass of different physical states is divided into 18 different combinations based on the results of lab tests and rock mass stability of each state is evaluated using a stability evaluation criterion we put forward. The numerical simulation of tunnel excavation is further carried out for determining the sub-level classification. A decision tree model is applied for further studying the relationship between physical and mechanical indices to ensure accurate prediction. The result shows that the prediction system works with high accuracy and can be used for engineering reference for fully weathered red sandstone rock mass.

Triaxial Creep Behavior of Red Sandstone in Freeze-Thaw Environments

To investigate the time-dependent mechanical properties of rock masses in cold regions under the effects of freeze-thaw cycling and long-term loading, triaxial multilevel loading and unloading creep tests were performed on saturated red sandstone samples subjected to different numbers of freeze-thaw cycles. The effects of freeze-thaw cycles and confining pressure on the creep properties, long-term strength, and creep failure mode of the rock were analyzed. The effect of freeze-thaw cycles on the microstructure of the rock was analyzed using scanning electron microscopy. The results showed that as the number of freeze-thaw cycles increased, the rock particle boundaries became more distinct, and more pores formed. The effect of freeze-thaw cycles on the creep deformation of red sandstone was related to the loading stress level. At low stress levels, the rock viscoelastic strain increased gradually and almost linearly with an increasing number of freeze-thaw cycles; in contrast, at high stress levels, the rock viscoelastic strain increased nonlinearly. The viscoplastic strain increased almost linearly with increasing freeze-thaw cycles. The fourth loading stress level (70% σ c ) corresponded to the transition of the creep deformation of the red sandstone. When the confining pressure was low, a higher stress level caused the confining pressure to have a more significant effect on the creep strain. However, as the confining pressure continued to increase, the effect of the confining pressure on the creep strain eventually disappeared. The long-term strength of the red sandstone decreased approximately linearly with an increase in the number of freeze-thaw cycles. When the number of freeze-thaw cycles and the confining pressure were high, the rock samples formed a transverse shear plane and were more fragmented than those without a transverse shear plane. These results provide a reference for construction in rock mass engineering and long-term stability analysis in cold regions.

Numerical Study on Anisotropic Influence of Joint Spacing on Mechanical Behavior of Rock Mass Models under Uniaxial Compression

Mechanical properties of rock masses are dominated by the nonlinear response of joints and their arrangement. In this paper, combined influences of joint spacing (s) and joint inclination angle (β) on mechanical behavior of rock mass models with large open joints under uniaxial compression were investigated by PFC modeling. With a large amount of local measurement circles placed along the pre-defined measurement lines (ML), stresses and joint response parameters at different scales (the measurement circles, the MLs and the whole specimen) were defined and calculated. It was found that macroscopic behaviors of the jointed specimens, such as four types of deformation behaviors, four failure modes, strength, deformability modulus and ductility index, are dominated by nonlinear response of the joint system, especially the interaction between the joints and rock bridges. The joints may experience three stages, i.e., starting to close, closed and opening again. On the joint plane, the peak stresses of the rock bridges and those of the joints may not be reached at the same time; i.e., joint strength mobilization happens with the loss of the rock bridges’ resistance. The influence of s on specimen behavior is little for β = 90°, obvious for β = 0° or 30° and significant for β = 45° or 60°, and this can be related to their different microscopic damage mechanisms.

Geostatistics-block-based characterization of heterogeneous rock mass and its application on ultimate pit limit optimization: a case study

For an open-pit mine, the slope must remain stable throughout the life of mining operation, and it follows that an optimized ultimate pit limit (UPL) should have the slope stability commensurate with economic benefit. In the Shuguang gold and copper mine, a geostatistics-block-based method is used to characterize the heterogeneous mechanical properties of rock mass. Then, the detailed slope stability analyses for four possible slope configuration designs using heterogenous mechanical parameter block model are performed to determine the steepest safe slope angle, and the steepest safe slope angle is next used for the UPL optimization. Compared with the original UPL assuming the rock mass is homogeneous in the same lithology, the slope angle for the optimized UPL has an average 1° to 6° increase, and the optimized UPL can bring 15.84 million tons of ore and reduce 20.83 million tons of waste rock. The result indicated that the application of geostatistics can make practical use of geotechnical information to improve slope stability, and slope configurations, and thereby optimize the UPL and so bring economic benefit.

Discrete Element Modeling on Mechanical Behavior of Heterogeneous Rock Containing X-Shaped Fissure under Uniaxial Compression

Based on the experimental results of an intact rock specimen under uniaxial compression, particle flow code (PFC2D) was adopted to carry out a discrete element modeling (DEM) for the mechanical behavior of heterogeneous rocks containing X-shaped fissures (two intersecting symmetric single fissures) under uniaxial compression. The influences of β (the acute angle between two single fissures) and the direction angle α (the acute angle between the bisector of β and perpendicular to the loading direction) on the strength, deformation, energy, crack propagation, and ultimate failure mode were analyzed in detail. Numerical simulated results showed the following: (1) Due to the X-shaped fissures, not only the peak strength, elastic modulus, crack initiation stress, and damage stress were significantly reduced, and the reduced degree of the peak strength was obviously greater than that of the elastic modulus, but also the brittleness and energy were significantly weakened. (2) The peak strength and elastic modulus generally decreased with the increase of β and increased with the increase of α . Moreover, the change trends of crack initiation stress, damage stress, boundary energy, and total strain energy at the peak stress were consistent with the peak strength. (3) Regardless of the changes of α and β , models all firstly initiated wing cracks at the two tips of the single fissure with a larger inclination angle, and the crack initiation angle decreased with the increase of the inclination angle of the single fissure. (4) The fracture was dominated by tensile microcracks, and no microcracks were generated in a certain range of the X-shaped fissure center. The failure mode was mainly split along the axial direction, and the failure surface started from the tips of the fissure and extended to both ends of models. (5) The uniaxial compressive strength and elastic modulus increased exponentially with the increase of the homogeneity factor. When the homogeneity factor was small, the microcracks were more evenly distributed in the models; when the homogeneity factor was large, the microcracks were mainly concentrated at the tips of the fissure in the models. This study can provide some references for the correct understanding of the mechanical properties of rock masses containing X-shaped fissures.

Phase field modeling of hydraulic fracture propagation in spatially variable rock masses

Due to differences in mineral compositions, sedimentary conditions, stress history, and geological processes, the spatial variability of the mechanical properties of rock masses is usually considerable. Therefore, the influence of the spatial variability of rock mass parameters on the irregular propagation of hydraulic fractures should be studied. In this work, an efficient approach is proposed for studying the irregular propagation of hydraulic fractures considering the spatial variability of rock mass parameters; this approach is based on the phase field method and random field theory. Combined with random field theory, the phase field method is adopted to simulate the fracture propagation in a spatially variable rock mass. Random fields of the Young’s modulus are generated using the Cholesky decomposition method and then embedded into the phase field model. The influences of different scales of fluctuation of the rock mass parameters’ random fields on the fracture shape under fluid-driven conditions are investigated in this study. The results indicate that the spatial variability of the Young’s modulus has a significant influence on the propagation of hydraulic fractures.

Method for calculating the shear strength of rock masses with different combined structural planes based on the 3D printing technology

The mechanical behavior of rock masses with different combined structural planes is poorly understood because of the difficulties associated with the performance of rock observations and analyses from the surface, collection of samples during field investigations, specimen preparation, and laboratory tests. The combination of rock mass structural planes has a significant effect on the rock mass mechanical properties. The three-dimensional (3D) printing technology can conveniently create 3D entities with complex structures, thereby providing an unprecedented opportunity to break through this bottleneck. In this study, model samples of structural surface models with different combinations are printed using the 3D printing technology, and a cement slurry with 3:1 water–cement ratio is used as the structural body to produce rock masses with different combined structural planes. The method replicates well the morphological features of natural joints. Moreover, the shear properties and the failure characteristics are stable and consistent. Direct shear tests are also performed on the rock masses of different combined structural planes from the intersection line parallel and perpendicular to the structural planes to obtain the relevant mechanical parameters and rock mass failure modes. The results prove the feasibility of the 3D printing technology in the experimental study of rock mass mechanics and show that the strength and failure modes of rock masses with different combined structural planes are different. A calculation method for the shear strength of rock masses with different combined structural planes is proposed herein based on the experimental data and the Mohr–Coulomb theory, and the method’s feasibility is verified by several examples.

Numerical appraisal of rock mass anisotropy effect on elastic deformations of a circular tunnel

The paper describes effects of anisotropic mechanical properties of rock masses on elastic behaviour of a circular tunnel under both hydrostatic and non-hydrostatic in situ stress states. This study is based on field data obtained from two actual case studies. In both cases, the rock masses have transversely isotropic structures. Hence, a 2D finite element modelling based on the equivalent continuum approach is used for the analysis. The tunnel deformation behaviour has been investigated for both isotropic and transversely isotropic conditions. To evaluate the degree of anisotropy of rock mass, an “anisotropy index” and a “normalized displacement ratio” have been defined. The effect of orientation of the isotropic planes is further investigated. The results show that in a hydrostatic stress state, the maximum displacement always occurs in a direction perpendicular to the isotropic planes. In this case, three empirical equations have been developed to compute the normalized displacement ratio, the deviation, and the direction of displacement vector at any arbitrary point on the tunnel periphery. The results further show that if the anisotropy index increases, the displacement difference (the difference between the maximum and the minimum displacements) on the tunnel walls increases too. For the non-hydrostatic stress state, simultaneous effects of stress ratio, anisotropy index, and orientation of isotropic planes on normalized displacements have been investigated. In this case, the location of maximum displacement inclines towards the direction of major principal stress. This effect is more noticeable when the isotropic planes are oriented at an angle of 90° relative to the direction of the major principal stress. The paper also provides an empirical equation to determine the location of maximum displacement on the tunnel walls. Finally, the practical application of the results is further illustrated by an actual case study.

Study on the Generation Mechanism and Development Law of the Zonal Disintegration in Deep Burial Tunnels

In the development of underground spaces, we found that the mechanical properties of rock mass often demonstrate strong nonlinear characteristics. Some new phenomena emerge in deep rock mass engineering. This includes zonal disintegration and rock burst. Zonal disintegration is very important in deep tunnels. In this paper, we start with the mechanical properties of deep rocks to understand the preconditions for zonal disintegration. Using the Failure Approach Index (FAI), the process of zonal disintegration can be modeled by FLAC (FISH language). Our results indicate that tensile failure in the Supporting Pressure Zone (SPZ) is a precondition for zonal disintegration. Various factors that affect the generation of zonal disintegration are studied. When the maximum stress is in the axial direction, zonal disintegration will be present in deep tunnels. The high axial stress is necessary for zonal disintegration. We will present a zonal disintegration simulation in one coal mine for comparison with the borehole teleview data. We suggest some measures to prevent the development of zonal disintegration.

Experimental study on mechanical properties of multi-layered rock mass and statistical damage constitutive model under hydraulic-mechanical coupling

The triaxial compression tests of multi-layered rock mass samples prepared from the laboratory were carried out by using the rock servo-controlled triaxial rheological test system, and the mechanical properties of multi-layered rock mass are studied. According to the test results, the deformation characteristics and failure modes of multi-layered rock mass samples are analysed. The relationship between layers and mechanical parameters of rock mass samples is discussed. The results show that the peak strength and the peak strain increases along with the increase of confining pressure. Failure forms of multi-layered rock mass samples include monoclinic shear failure, tension crack failure, and interfacial shear slip failure. The more layers, the more broken the samples are. The more layers there are, the smaller the peak strength and the cohesive force of multi-layered rock mass samples are. Moreover, there is an exponential relationship between the internal friction angle and the number of layers. Based on the test results, considering the weakening of the mechanical properties of rock mass by the number of layers, the statistical damage constitutive model of the rock mass under hydraulic-mechanical coupling is established and verified. The results indicate that the model fits the experimental data well.

Anisotropic Constitutive Model of Intermittent Columnar Jointed Rock Masses Based on the Cosserat Theory

In this work, an anisotropic constitutive model of hexagonal columnar jointed rock masses is established to describe the distribution law of deformation and the failure of columnar joint caverns under anisotropic conditions, and is implemented to study the columnar jointed rock mass at the dam site of the Baihetan Hydropower Station on the Jinsha River. The model is based on the Cosserat theory and considers the mesoscopic bending effect on the macroscopic mean. The influences of joint plane inclination on equivalent anisotropic elastic parameters are discussed via the introduction of an off-axis transformation matrix and the analysis of an example. It is also pointed out that the six-prism columnar jointed rock mass changes from transverse isotropy to anisotropy under the influence of the angle. A numerical calculation program of the Cosserat constitutive model is developed and is applied to the simulation calculation of a Baihetan diversion tunnel to compare and analyze the respective plastic zones and stress distributions after tunnel excavation under both isotropic and anisotropic conditions. The results reveal that, compared with the isotropic model, the proposed Cosserat anisotropic model better reflects the state of stress and asymmetric distribution of the plastic zone after tunnel excavation, and the actual deformation of the surrounding rock of the tunnel is greater than that calculated by the isotropic method. The results aid in a better understanding of the mechanical properties of rock masses.

Hydraulic pressure effect on mechanical properties and permeabilities of layered rock mass: an experimental study

The triaxial compression tests under different hydraulic pressures and low confining pressure were carried out to study the hydraulic pressure effect on the mechanical properties and permeabilities of layered rock mass. In general, the results show that the increase of hydraulic pressure reduces the peak strength of layered rock mass and the layer structure changes the mechanical properties of rock mass. With the increase of hydraulic pressure, the peak strength of layered rock mass decreases sharply and then slows down. The peak permeabilities of layered rock mass occurred later than the time when the strength come to the peak. The increase of hydraulic pressure will accelerate the propagation of cracks and significantly enhance the peak permeability of layered rock mass. With the increase of the layer number, the effect of hydraulic pressure becomes more distinct. The initial permeability and the peak permeability increase largely. The increase of hydraulic pressure promotes the expansion and penetration of cracks, so the rock mass develops from tensile failure to the composite failure forms including shear failure and interfacial shear slip failure.

Assessment of block size distribution in fractured rock mass and its influence on rock mass mechanical behavior

The response of rock mass to engineering activities related to environment greatly depends on the scale of rock mass. Therefore, the scale dependency of rock mechanical behavior under different rock mass conditions is investigated in this research. As a crucial parameter, the volume of the block provides a fundamental understanding to define the rock mass condition and possible mechanical response. In this paper, at first, a systematic approach to calculate the block size distribution (BSD) based on the natural fracture parameters using most suitable distribution functions was established with the R language. Then, the rock mass parameters were extracted from core mapping in the depth of 1500 m–2000 m and the BSD was presented in a similar manner to soil particle size distribution. Finally, the rock mass behavior under different block sizes was investigated. The results showed that Vb25 = 3.4 dm3, Vb50 = 6.4 dm3, and Vb75 = 11.2 dm3, which were the average percentages to represent the BSD. In the research area, therefore, the fractured rock mass was dominated by minor blocks. Besides, the variation of rock mass deformation vs BSD showed that the fractured rock mass was aggravated with the decrease in the block size. The results will enhance the effect of BSD on rock mass mechanical properties.

A damage constitutive model for shear behavior of joints based on determination of the yield point

Rock joints, a ubiquitous geological phenomenon, greatly affect the mechanical properties of rock masses for engineering purposes. The shear constitutive model of rock joints plays an important role in the research in this field, both experimentally and theoretically. However, most existing constitutive models utilize too many parameters with unclear physical significance and cannot reflect the overall process of shearing due to the absence of prepeak and postpeak deformation. Therefore, this paper focuses on the characteristics of joints entering strain hardening after the yield point during shearing. Based on the statistical damage theory and the combination of macro- and microdeformation characteristics, a new damage constitutive model was established to accurately depict the deformation of the whole joint shearing process. In addition, a quantitative analysis method based on the shear stress difference is proposed to determine the yield point, which is of great significance to improve the capability of this proposed model and is easy to program, effectively avoiding subjective factors. It can be deduced that the new model can describe the deformation characteristics and damage evolution law of the whole joint shearing process, and it has a simple model form as well as few parameters with reasonable physical meaning. The new model was adopted to fit the experimental data from previous studies. The results indicate that the new model shows great consistency with the experiments, which reflects the feasibility and capability of this proposed model.