Shear mechanical properties and energy evolution of rock-like samples containing multiple combinations of non-persistent joints  

作　　者：Daping Tai Shengwen Qi Bowen Zheng Chonglang Wang Songfeng Guo Guangming Luo 

机构地区：[1]Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing,100029,China [2]University of Chinese Academy of Sciences,Beijing,100049,China [3]Innovation Academy for Earth Science,Chinese Academy of Sciences,Beijing,100029,China [4]China-Pakistan Joint Research Center on Earth Sciences,CAS-HEC,Islamabad,45320,Pakistan [5]Department of Civil and Mineral Engineering,University of Toronto,Toronto,Ontario,M5S 1A4,Canada

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2023年第7期1651-1670,共20页岩石力学与岩土工程学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.41825018);the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0904).

摘　　要：Discontinuities are often considered as important factors responsible for the instability caused by shear failure in engineering rock mass,and energy-driven instability is the root cause of rock failure.However,few studies focus on the energy evolution during the failure process using a three-dimensional(3D)numerical model.In this study,a series of laboratory direct shear tests on rock-like samples is numer-ically simulated using bonded particle models(BPMs)with multiple combinations of discontinuous in the particle flow code(PFC3D),in which the location and size of the particles conform to the uniform distribution.The effects of joint row number and inclination on the stress-strain characteristics and failure mode of rock were studied from the perspective of microcrack growth and energy evolution.The results showed that,when the number of joint rows Nr>1,the shear failure region does not change with the increase of Nr for the type B(2-columnn multiple-row at center)and the type C(2-column multiple-row at edge)as compared to the type A(1-column multiple-row at center)joint models.Notably,joints significantly increase the post-peak energy dissipation but have little effect on the proportion of energy before the peak.Friction consumes most of the energy while kinetic energy accounts for less than 1%of total energy during the shear process.Peak elastic strain energy follows the variation trend of peak shear displacement.The development and accumulation of microcracks directly affect the energy dissipation,and there is a significant linear relationship between the cumulative number of critical microcracks and the critical dissipated energy at the failure,when the dip direction of joints is opposite to the shear direction,more microcracks will be accumulated at the peak time,resulting in more energy dissipation.The results contribute to deeply understanding the shear failure process of non-persistent jointed mass.

关 键 词：Non-persistent joints Shear behavior Energy evolution Particle flow code(PFC3D) 

分 类 号：TU45[建筑科学—岩土工程]