期刊文献+
共找到11篇文章
< 1 >
每页显示 20 50 100
Cyclic shear behavior of en-echelon joints under constant normal stiffness conditions 被引量:1
1
作者 Bin Wang Yujing Jiang +3 位作者 Qiangyong Zhang Hongbin Chen Richeng Liu Yuanchao Zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第9期3419-3436,共18页
To reveal the mechanism of shear failure of en-echelon joints under cyclic loading,such as during earthquakes,we conducted a series of cyclic shear tests of en-echelon joints under constant normal stiffness(CNS)condit... To reveal the mechanism of shear failure of en-echelon joints under cyclic loading,such as during earthquakes,we conducted a series of cyclic shear tests of en-echelon joints under constant normal stiffness(CNS)conditions.We analyzed the evolution of shear stress,normal stress,stress path,dilatancy characteristics,and friction coefficient and revealed the failure mechanisms of en-echelon joints at different angles.The results show that the cyclic shear behavior of the en-echelon joints is closely related to the joint angle,with the shear strength at a positive angle exceeding that at a negative angle during shear cycles.As the number of cycles increases,the shear strength decreases rapidly,and the difference between the varying angles gradually decreases.Dilation occurs in the early shear cycles(1 and 2),while contraction is the main feature in later cycles(310).The friction coefficient decreases with the number of cycles and exhibits a more significant sensitivity to joint angles than shear cycles.The joint angle determines the asperities on the rupture surfaces and the block size,and thus determines the subsequent shear failure mode(block crushing and asperity degradation).At positive angles,block size is more greater and asperities on the rupture surface are smaller than at nonpositive angles.Therefore,the cyclic shear behavior is controlled by block crushing at positive angles and asperity degradation at negative angles. 展开更多
关键词 En-echelon joint Cyclic shear tests Shear stress normal displacement Constant normal stiffness(CNS)
下载PDF
Laboratory investigation into effect of bolt profiles on shear behaviors of bolt-grout interface under constant normal stiffness (CNS) conditions 被引量:4
2
作者 Guojian Cui Chuanqing Zhang +2 位作者 Yibin Pan Liang Deng Hui Zhou 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2020年第6期1234-1248,共15页
Rock bolts have been widely used for stabilizing rock mass in geotechnical engineering.It is acknowledged that the bolt profiles have a sound influence on the support effect of the rock bolting system.Previous studies... Rock bolts have been widely used for stabilizing rock mass in geotechnical engineering.It is acknowledged that the bolt profiles have a sound influence on the support effect of the rock bolting system.Previous studies have proposed some optimal rib parameters(e.g.rib spacing);unfortunately,the interface shear behaviors are generally ignored.Therefore,determination of radial stress and radial displacement on the bolt-grout interface using traditional pull-out tests is not possible.The load-bearing capacity and deformation capacity vary as bolt profiles differ,suggesting that the support effect of the bolting system can be enhanced by optimizing bolt profiles.The aim of this study is to investigate the effects of bolt profiles(with/without ribs,rib spacing,and rib height)on the shear behaviors between the rock bolt and grout material using direct shear tests.Thereby,systematic interfacial shear tests with different bolt profiles were performed under both constant normal load(CNL)and constant normal stiffness(CNS)boundary conditions.The results suggested that rib spacing has a more marked influence on the interface shear behavior than rib height does,in particular at the post-yield stage.The results could facilitate our understanding of bolt-grout interface shear behavior under CNS conditions,and optimize selection of rock bolts under in situ rock conditions. 展开更多
关键词 Bolt profile Constant normal stiffness(CNS) Shear test Interface failure characteristics Shear behaviors
下载PDF
Sliding modes of fault activation under constant normal stiffness conditions 被引量:3
3
作者 Chuanqing Zhang Jie Xu +3 位作者 Shengji Jin Guojian Cui Yuhang Guo Lingyu Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第5期1213-1225,共13页
Fault activation has been the focus of research community for years.However,the studies of fault activation remain immature,such as the fault activation mode and its major factors under constant normal stiffness(CNS)c... Fault activation has been the focus of research community for years.However,the studies of fault activation remain immature,such as the fault activation mode and its major factors under constant normal stiffness(CNS)conditions associated with large thickness of fault surrounding rock mass.In this study,the rock friction experiments were conducted to understand the fault activation modes under the CNS conditions.Two major parameters,i.e.the initial normal stress and loading rate,were considered and calibrated in the tests.To reveal the response mechanism of fault activation,the local strains near the fault plane were recorded,and the macroscopic stresses and displacements were analyzed.The testing results show that the effect of displacement-controlled loading rate is more pronounced under the CNS conditions than that under constant normal load(CNL)conditions.Both the normal and shear stresses drop suddenly when the stick-slip occurs.The decrease and increase of the normal stress are synchronous with the shear stress in the regular stick-slip scenario,but mismatch with the shear stress during the chaotic stick-slip process.The results are helpful for understanding the fault sliding mode and the prediction and prevention of fault slip. 展开更多
关键词 Fault activation Rock friction mechanics Sliding modes Constant normal stiffness(CNS) Displacement-controlled loading rates ROCKBURST
下载PDF
A review of shear strength models for rock joints subjected to constant normal stiffness 被引量:12
4
作者 Sivanathan Thirukumaran Buddhima Indraratna 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2016年第3期405-414,共10页
The typical shear behaviour of rough joints has been studied under constant normal load/stress (CNL) boundary conditions, but recent studies have shown that this boundary condition may not replicate true practical s... The typical shear behaviour of rough joints has been studied under constant normal load/stress (CNL) boundary conditions, but recent studies have shown that this boundary condition may not replicate true practical situations. Constant normal stiffness (CNS) is more appropriate to describe the stress-strain response of field joints since the CNS boundary condition is more realistic than CNL. The practical implications of CNS are movements of unstable blocks in the roof or walls of an underground excavation, reinforced rock wedges sliding in a rock slope or foundation, and the vertical movement of rock-socketed concrete piles. In this paper, the highlights and limitations of the existing models used to predict the shear strength/behaviour of joints under CNS conditions are discussed in depth. 展开更多
关键词 Rock jointsShear strengthDilationAsperity damageConstant normal stiffness (CNS)
下载PDF
A comparative study for determining rock joint normal stiffness with destructive uniaxial compression and nondestructive ultrasonic wave testing
5
作者 Zhenghu Zhang Jianbo Zhu Jianhui Deng 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第7期1700-1712,共13页
Rock joints are one of the vital discontinuities in a natural rock mass.How to accurately and conveniently determine joint normal stiffness is therefore significant in rock mechanics.Here,first,seven existing methods ... Rock joints are one of the vital discontinuities in a natural rock mass.How to accurately and conveniently determine joint normal stiffness is therefore significant in rock mechanics.Here,first,seven existing methods for determining joint normal stiffness were introduced and reviewed,among which MethodⅠ(the indirect measurement method),MethodⅡ(the direct determination method),MethodⅢ(the across-joint strain gauge measurement method)and MethodⅣ(the deformation measuring ring method)are via destructive uniaxial compression testing,while MethodⅤ(the best fitting method),MethodⅥ(the rapid evaluation method)and MethodⅦ(the effective modulus method)are through wave propagation principles and nondestructive ultrasonic testing.Subsequently,laboratory tests of intact and jointed sandstone specimens were conducted following the testing requirements and pro-cedures of those seven methods.A comparison among those methods was then performed.The results show that Method I,i.e.the benchmark method,is reliable and stable.MethodⅡhas a conceptual drawback,and its accuracy is acceptable at only very low stress levels.Relative errors in the results from MethodⅢare very large.With MethodⅣ,the testing results are sufficiently accurate despite the strict testing environment and complicated testing procedures.The results from MethodⅤare greatly unstable and significantly dependent on the natural frequency of the transducers.The joint normal stiffness determined with MethodⅥis stable and accurate,although data processing is complex.MethodⅦcould be adopted to determine the joint normal stiffness corresponding to the rock elastic deformation phase only.Consequently,it is suggested that MethodsⅠ,ⅣandⅥshould be adopted for the mea-surement of joint normal stiffness.The findings could be helpful in selecting an appropriate method to determine joint normal stiffness and,hence,to better solve discontinuous rock mass problems. 展开更多
关键词 normal stiffness Rock joint Uniaxial compression Ultrasonic wave
下载PDF
Effect of bolt inclination angle on shear behavior ofbolted joints under CNL and CNS conditions 被引量:14
6
作者 CUI Guo-jian ZHANG Chuan-qing +3 位作者 CHEN Jian-lin YANG Fan-jie ZHOU Hui LU Jing-jing 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第3期937-950,共14页
Rock bolts are widely used in rock engineering projects to improve the shear capacity of the jointed rock mass.The bolt inclination angle with respect to the shear plane has a remarkable influence on the bolting perfo... Rock bolts are widely used in rock engineering projects to improve the shear capacity of the jointed rock mass.The bolt inclination angle with respect to the shear plane has a remarkable influence on the bolting performance.In this study,a new artificial molding method based on 3D scanning and printing technology was first proposed to prepare bolted joints with an inclined bolt.Then,the effects of the bolt inclination angle and boundary conditions on the shear behavior and failure characteristic of bolted joints were addressed by conducting direct shear tests under both CNL and CNS conditions.Results indicated that rock bolt could significantly improve the shear behavior of rock joints,especially in the post-yield deformation region.With the increase of bolt inclination angle,both the maximum shear stress and the maximum friction coefficient increased first and then decreased,while the maximum normal displacement decreased monotonously.Compared with CNL conditions,the maximum shear stress was larger,whereas the maximum normal displacement and friction coefficient were smaller under the CNS conditions.Furthermore,more asperity damage was observed under the CNS conditions due to the increased normal stress on the shear plane. 展开更多
关键词 bolted joints bolt inclination angle constant normal load(CNL)boundary conditions constant normal stiffness(CNS)boundary conditions direct shear test asperity damage
下载PDF
Modeling of Mechanical Behavior of Fractal Rock Joint 被引量:2
7
作者 Jinan bang Marek A. Kwasniewski( Resources Engineering School. University of Science and Technology Beijing, Bejing 100083, China)( Rock Mechanics Laboratory, Faculty of Mining and Geology, Technical University of Silesia, Gliwice , Poland) 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 1999年第3期157-164,共8页
The present study shows that naturally developed fracture surfaces in rocks display the properties of self-affine fractals. Surface roughness can be quantitatively characterized by fractal dimension D and the intercep... The present study shows that naturally developed fracture surfaces in rocks display the properties of self-affine fractals. Surface roughness can be quantitatively characterized by fractal dimension D and the intercept A on the log-log plot of variance: the former describes the irregularity and the later is statistically analogues to the slopes of asperities. In order to confirm the effects of these fractalparameters on the properties and mechanical behavior of rock joints, which have been observed in experiments under both normal andshear loadings, a theoretic model of rock joint is proposed on the basis of contact mechanics. The shape of asperity at contact is assumed to have a sinusoidal form in its representative scale r, with fractal dimension D and the intercept A. The model considers different local contact mechanisms, such as elastic deformation, frictional sliding and tensile fracture of the asperity. The empirical evolution law of surface damage developed in experiment is implemented into the model to up-date geometry of asperity in loading history. The effects of surface roughness characterized by D, A and re on normal and shear deformation of rock joint have been elaborated. 展开更多
关键词 fractal roughness mechanical behavior rock joints fractal dimension the intercept contact mechanics normal stiffness shear stiffness surface damage
下载PDF
Propagation of plane waves in thermoelastic cubic crystal material with two relaxation times
8
作者 Rajneesh Kumar Manjeet Singh 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2007年第5期627-641,共15页
A problem concerned with the reflection and refraction of thermoelastic plane waves at an imperfect interface between two generalized thermally conducting cubic crystal solid half-spaces of different elastic and therm... A problem concerned with the reflection and refraction of thermoelastic plane waves at an imperfect interface between two generalized thermally conducting cubic crystal solid half-spaces of different elastic and thermal properties with two relaxation times has been investigated. The generalized thermoelastic theory with two relaxation times developed by Green and Lindsay has been used to study the problem. The expressions for the reflection and refraction coefficients which are the ratios of the amplitudes of reflected and refracted waves to the amplitude of incident waves are obtained for an imperfect boundary and deduced for normal stiffness, transverse stiffness, thermal contact conductance, slip and welded boundaries. Amplitude ratios of different reflected and refracted waves for different boundaries with angle of emergence have been compared graphically for different incident waves. It is observed that the amplitude ratios of reflected and refracted waves are affected by the stiffness and thermal properties of the media. 展开更多
关键词 generalized thermoelasticity normal stiffness transverse stiffness thermal contact conductance cubic crystal amplitude ratios
下载PDF
Effects of joint persistence and testing conditions on cyclic shear behavior of en-echelon joints under CNS conditions
9
作者 Bin Wang Yujing Jiang +1 位作者 Qiangyong Zhang Hongbin Chen 《Rock Mechanics Bulletin》 2024年第4期123-141,共19页
Cyclic shear tests on rock joints serve as a practical strategy for understanding the shear behavior of jointed rock masses under seismic conditions.We explored the cyclic shear behavior of en-echelon and how joint pe... Cyclic shear tests on rock joints serve as a practical strategy for understanding the shear behavior of jointed rock masses under seismic conditions.We explored the cyclic shear behavior of en-echelon and how joint persistence and test conditions(initial normal stress,normal stiffness,shear velocity,and cyclic distance)influence it through cyclic shear tests under CNS conditions.The results revealed a through-going shear zone induced by cyclic loads,characterized by abrasive rupture surfaces and brecciated material.Key findings included that increased joint persistence enlarged and smoothened the shear zone,while increased initial normal stress and cyclic distance,and decreased normal stiffness and shear velocity,diminished and roughened the brecciated material.Shear strength decreased across shear cycles,with the most significant reduction in the initial shear cycle.After ten cycles,the shear strength damage factor D varied from 0.785 to 0.909.Shear strength degradation was particularly sensitive to normal stiffness and cyclic distance.Low joint persistence,high initial normal stress,high normal stiffness,slow shear velocity,and large cyclic distance were the most destabilizing combinations.Cyclic loads significantly compressed en-echelon joints,with compressibility highly dependent on normal stress and stiffness.The frictional coefficient initially declined and then increased under a rising cycle number.This work provides crucial insights for understanding and predicting the mechanical response of en-echelon joints under seismic conditions. 展开更多
关键词 Cyclic shear test Shear strength degradation Constant normal stiffness En-echelon joint Dilation characteristics
原文传递
Shear behaviour of anchored jointed rock mass under different engineering conditions considering damage and joint surface morphology 被引量:1
10
作者 Zenghui Zhao Wei Sun +1 位作者 Shaojie Chen Hao Liu 《Underground Space》 SCIE EI CSCD 2023年第6期316-334,共19页
According to different geological conditions and engineering disturbance,three dimensional numerical models of anchored jointed rock mass with two kinds of boundary conditions of constant normal load(CNL)and constant ... According to different geological conditions and engineering disturbance,three dimensional numerical models of anchored jointed rock mass with two kinds of boundary conditions of constant normal load(CNL)and constant normal stiffness(CNS)were constructed considering the ductility damage of rockbolt,the stiffness degradation of grouting layer and the joint surface roughness.The effects of anchorage angle,joint surface morphology,and boundary conditions on the shear performance of anchorage system were analyzed,and the failure characteristics under different working conditions were revealed.Finally,the analytical solution of shear strength of anchored system was established.Results show that the larger the anchorage angle is,the more serious the necking phenomenon of rockbolt will be.The damage degree of the bonding layer and the horizontal displacement of the bedding rock mass decrease with the increase of the joint surface roughness.The CNL condition is to instantaneously apply high normal stress,and the CNS condition is to gradually form a high normal stress environment through the superposition of increment on the basis of the initial value,which can resist greater transverse load.This is equivalent to enhancing the ductility of the rockbolt.The shear strength of the system increases with the increase of normal stress and normal stiffness.Ignoring the normal stiffness will underestimate the shear strength. 展开更多
关键词 Anchored jointed rock mass normal stress normal stiffness Progressive damage
原文传递
A semi-analytical approach to the elastic loading behaviour of rough surfaces 被引量:1
11
作者 Xiaogang ZHANG Yali ZHANG Zhongmin JIN 《Friction》 SCIE CSCD 2020年第5期970-981,共12页
The elastic loading behaviour of rough surfaces is derived based on the physical understanding of the contact phenomena, where the pressure distribution is analytically obtained without any negative values or converge... The elastic loading behaviour of rough surfaces is derived based on the physical understanding of the contact phenomena, where the pressure distribution is analytically obtained without any negative values or convergence problems, thus the evolution of the contact behaviour is obtained in a semi-analytical manner. Numerical results obtained by the proposed approach facilitate the understanding of the contact behaviour in the following aspects: 1) the ratio of contact area to load decreases with an increase in real contact area;2) normal approach-load relationship is approximated by an exponential decay under relatively small loads and a linear decay under relatively large loads;and 3) average gap shows an exponential relationship with load only in moderate load range. 展开更多
关键词 surface roughness real contact area interfacial stiffness normal contact stiffness
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部