|
|
|
| Investigation on the macro-meso shear damage mechanical behaviors of fractured rocks |
| CHEN Xin1，ZHOU Xiaohan1，2，3，XU Bin1，2，3，LIU Xinrong1，2，3，GUO Xueyan1，
WANG Jiwen1，ZENG Xi1 |
| (1. School of Civil Engineering，Chongqing University，Chongqing 400045，China；2. National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Areas，Chongqing University，Chongqing 400045，China；3. Key Laboratory
of New Technology for Construction of Cities in Mountain Area of the Ministry of Education，
Chongqing University，Chongqing 400045，China) |
|
|
|
|
Abstract The laboratory direct shear test and PFC2D microscopic simulation were used to investigate the shear deformation，strength characteristics and damage evolution law of fractured rocks. The research results show that：(1) The shear strength-deformation curve of fractured rocks can be divided into four stages：compaction stage，approximate linear elastic stage，unstable development stage and residual deformation stage. (2) The peak shear deformation of fractured rocks is negatively correlated with the number of fractures(N)，the normal stress( ) and the shear rate(ν). And the peak shear stress of fractured rocks is negatively correlated with N and ν，while positively correlated with . Besides，the greater N is，the more obvious the effect of ν on the peak shear deformation is，and the greater ν is，the more significant the effect of N on peak shear deformation is. (3) With increasing the shear deformation，the number of meso-damage cracks(shear cracks and tensile cracks) increases with the variation characteristics of slight (Ⅰ) →steep (Ⅱ) →slow (Ⅲ). The frictional dissipation energy gradually increases，the elastic strain energy first increases and then decreases. Especially，the elastic strain energy of rock mass only accounts for 1/5～2/5 of the total energy of mesoscopic damage. (4) At the tip of the preset cracks，the micro-meso cracks initiate，expand and then penetrate. In the end，the central rock bridge is mainly damaged by tensile，and the failure modes of two sides shows shear(tensile) failure- tensile-shear failure- shear failure. The peak shear stress (displacement) is X-type＞M2＞round-hole＞Z-type. The damage cracks appear at the tip of pre-existing flaw，and also the top or bottom left of the hole. The distribution of cracks is basically the same for the X-type and M2 fractured rocks.
|
|
|
|
|
|
| [1] HOEK E，BRAY J. Rock slope engineering[M]. 3rd ed. London：Institution of Mining and Metallurgy，1981：83–120.
[2] GEHLE C，KUTTER H K. Breakage and shear behavior of intermittent rock joints[J]. International Journal of Rock Mechanics and Mining Sciences，2003，40(5)：687–700.
[3] XU B，LIU X，ZHOU X，et al. Investigation on the macro-meso fatigue damage mechanism of rock joints with multiscale asperities under pre-peak cyclic shear loading[J]. Soil Dynamics and Earthquake Engineering，2021，151：106958.
[4] ZHOU X P，ZHANG J Z，QIAN Q H，et al. Experimental investigation of progressive cracking processes in granite under uniaxial loading using digital imaging and AE techniques[J]. Journal of Structural Geology，2019，126：129–145.
[5] YIN Z，LIU X，YANG Z，et al. Shear characteristics and failure mode of hard brittle marl with parallel discontinuous structural plane[J]. Arabian Journal for Science and Engineering，2020，45(10)：8 219–8 229.
[6] 肖维民，刘伟超，朱占元. 基于正反向直剪试验的岩石节理JRC值计算研究[J]. 岩石力学与工程学报，2021，40(增2)：3 098–3 106. (XIAO Weimin，LIU Weichao，ZHU Zhanyuan. Study on calculation of rock joint JRC value based on forward and reverse direct shear tests[J]. Chinese Journal of Rock Mechanics and Engineering，2021，40(Supp.2)：3 098–3 106.(in Chinese))
[7] LAJTAI E Z. Shear strength of weakness planes in rock[J]. International Journal of Rock Mechanics and Mining Sciences，1969，6(7)：499–515.
[8] STIMPSON B. Failure of slopes containing discontinuous planar joints[C]// Proceedings of 19th United States Symposium on Rock Mechanics(USRM). Reno，Nevada：University of Nevada，1978：296–300.
[9] 刘远明，夏才初. 直剪条件下非贯通节理岩体岩桥力学性质弱化机制及贯通模型初步研究[J]. 岩土力学，2010，31(3)：695–701.(LIU Yuanming，XIA Caichu. Weakening mechanism of mechanical behaviors and failure models of rock mass containing discontinuous joints under direct shear condition[J]. Rock and Soil Mechanics，2010，31(3)：695–701.(in Chinese))
[10] 黄 达，郭颖泉，朱谭谭，等. 法向卸荷条件下含单裂隙砂岩剪切强度与破坏特征试验研究[J]. 岩石力学与工程学报，2019，38(7)：1 297–1 306.(HUANG Da，GUO Yingquan，ZHU Tantan，et al. Experimental investigation on shear strength and failure characteristics of sandstone with a single preexisting flaw under unloading normal stress[J]. Chinese Journal of Rock Mechanics and Engineering，2019，38(7)：1 297–1 306.(in Chinese))
[11] 刘新荣，尹志明，王艳磊. 含V型相交裂隙岩体的力学特性及破坏模式试验[J]. 煤炭学报，2020，45(2)：651–659.(LIU Xinrong，YIN Zhiming，WANG Yanlei. Mechanical properties and failure mode of rock mass containing V-type intersecting fissures[J]. Journal of China Coal Society，2020，45(2)：651–659.(in Chinese))
[12] 武 旭，王 帆，席 迅，等. 正交型交叉裂隙岩石强度特征与破裂机制试验研究[J]. 煤炭学报，2020，45(7)：2 681–2 690.(WU Xu，WANG Fan，XI Xun，et al. Experimental investigation on the strength characteristics and fracture mechanism of rock with orthogonally crossed cracks[J]. Journal of China Coal Society，2020，45(7)：2 681–2 690.(in Chinese))
[13] 王桂林，梁再勇，张 亮，等. Z型裂隙对砂岩强度和破裂行为影响机制研究[J]. 岩土力学，2018，39(增2)：389–397.(WANG Guilin，LIANG Zaiyong，ZHANG Liang，et al. Study of influence mechanism of Z-type fissure on sandstone strength and fracture behavior[J]. Rock and Soil Mechanics，2018，39(Supp.2)：389–397.(in Chinese))
[14] 汪亦显，汪志强，张 伟，等. 含预制孔洞混凝土的断裂实验研究[J]. 北京理工大学学报，2019，39(12)：1 232–1 238.(WANG Yixian，WANG Zhiqiang，ZHANG Wei，et al. Experimental research on fracture of concrete with prefabricated holes[J]. Transactions of Beijing Institute of Technology，2019，39(12)：1 232–1 238.(in Chinese))
[15] 黄 达，岑夺丰. 单轴静–动相继压缩下单裂隙试样力学响应及能量耗散机制颗粒流模拟[J]. 岩石力学与工程学报，2013，32(9)：1 926–1 936.(HUANG Da，CHEN Duofeng. Mechanical responses and energy dissipation mechanism of rock specimen with a single fissure under static and dynamic uniaxial compression using particle flow code simulations[J]. Chinese Journal of Rock Mechanics and Engineering，2013，32(9)：1 926–1 936.(in Chinese))
[16] LIU X R，XU B，LIN G Y，et al. Experimental and numerical investigations on the macro-meso shear mechanical behaviors of artificial rock discontinuities with multiscale asperities[J]. Rock Mechanics and Rock Engineering，2021，54(8)：4 079–4 098.
[17] 刘新荣，许 彬，黄俊辉，等. 多形态贯通型岩体结构面宏细观剪切力学行为研究[J]. 岩土工程学报，2021，43(3)：406–415.(LIU Xinrong，XU Bin，HUANG Junhui，et al. Macro-meso shear mechanical behaviors of coalescent rock joints with different morphologies[J]. Chinese Journal of Geotechnical Engineering，2021，43(3)：406–415.(in Chinese))
[18] 王 刚，张学朋，蒋宇静，等. 基于颗粒离散元法的岩石节理面剪切破坏细观机制[J]. 中南大学学报：自然科学版，2015，46(4)：1 442–1 453.(WANG Gang，ZHANG Xuepeng，JIANG Yujing，et al. Meso-mechanism research on shear failure of rock joint based on particle discrete element method[J]. Journal of Central South University：Science and Technology，2015，46(4)：1 442–1 453.(in Chinese))
[19] 张鹏超. 单个非直裂隙红砂岩单轴压缩试验及颗粒流模拟研究[硕士学位论文][D]. 北京：中国矿业大学，2020.(ZHANG Pengchao. Experimental and particle flow simulation studies of red sandstone containing a single non-straight fissure under uniaxial compression[M. S. Thesis][D]. Beijing：China University of Mining and Technology，2020.(in Chinese))
[20] 周 喻，刘 冰，王 莉，等. 单轴压缩条件下含双圆孔类岩石试样力学特性的细观研究[J]. 岩石力学与工程学报，2017，36(11)：2 662–2 671.(ZHOU Yu，LIU Bing，WANG Li，et al. Mesoscopic mechanical properties of rock-like material containing two circular holes under uniaxial compression[J]. Chinese Journal of Rock Mechanics and Engineering，2017，36(11)：2 662–2 671.(in Chinese))
[21] 刘新荣，景 瑞，缪露莉，等. 巫山段消落带岸坡库岸再造模式及典型案例分析[J]. 岩石力学与工程学报，2020，39(7)：1 321–1 332. (LIU Xinrong，JING Rui，MIAO Luli，et al. Reconstruction models and typical case analysis of the fluctuation belt of reservoir bank slopes in Wushan[J]. Chinese Journal of Rock Mechanics and Engineering，2020，39(7)：1 321–1 332.(in Chinese)) |
|
|
|
2022, Vol. 41 
