Cracking behaviors and strength of rock-like samples with steps of different geometries under shear stress  

作　　者：LE Hui-lin WEI Ji-hong SUN Shao-rui ZHANG Chu-chu 

机构地区：[1]Department of Geology Engineering,Hohai University,Nanjing 210098,China [2]China Energy Engineering Group Jiangsu Power Design Institute Co.,Ltd.,Nanjing 210098,China

出　　处：《Journal of Mountain Science》2021年第5期1352-1370,共19页山地科学学报（英文）

基　　金：National Natural Science Foundation of China(No.42007256 and 41672258);the Fundamental Research Funds for the Central Universities(B210201002)。

摘　　要：Steps are distinctive features for estimating the movement of the upper and lower block of faults.However,studies about the influence of steps as a special type of discontinuity on cracking behaviors and strength of rock masses are limited.In this research,rock-like samples with steps and preexisting flaws were fabricated.Step height h and the inclination angle of gentle slope of the stepαwere set to different values.Direct shear tests were conducted on these samples under different normal stresses.The experimental results reveal that the inclination angle of the gentle slope of the stepα,step height h,and normal stress have an influence on the strength,crack initiation,and crack propagation of the samples.The experimental results show that crack behaviors and shear strength were affected by step inclination anglesαand step height h.As the normal stress increases,the improvement of the strength of samples with a large step height is larger than that of samples with a small step height,the improvement of the strength of samples withαof 10°is larger than that of samples withαof 0°and-10°.The discrete element method was used to simulate the shear test.Numerical results show five different types of displacement vectors,which can be used to determine whether the cracks are tensile cracks or shear cracks.The above conclusions can provide help for estimating mechanical properties and failure modes of rock masses with steps of different geometries.

关 键 词：Step Preexisting flaw Direct shear test Crack behavior Shear stress Numerical test 

分 类 号：TU45[建筑科学—岩土工程]