砂岩直接剪切试验三维离散元分析  

Direct shear test analysis of sandstone by 3D discrete element method

作　　者：杨开新 陈有亮[1] 蒋明镜[1,2,3,5] 王华宁 YANG Kaixin;CHEN Youliang;JIANG Mingjing;WANG Huaning(School of Environment and Architecture,University of Shanghai for Science and Technology,Shanghai 200093,China;State Key Laboratory of Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China;College of Civil Engineering,Tongji University,Shanghai 200092,China;School of Aerospace Engineering and Applied Mechanics,Tongji University,Shanghai 200092,China;School of Civil Engineering,Tianjin University,Tianjin 300072,China)

机构地区：[1]上海理工大学土木工程系,上海200093 [2]同济大学土木工程防灾重点实验室,上海200092 [3]同济大学土木工程学院,上海200092 [4]同济大学航空航天与力学学院,上海200092 [5]天津大学建筑工程学院,天津300072

出　　处：《水资源与水工程学报》2020年第6期216-223,共8页Journal of Water Resources and Water Engineering

基　　金：国家重点基础研究发展计划(973计划)项目(2014CB046901)。

摘　　要：为了研究高地应力作用下的深部岩体的剪切力学特性,将半经验半理论胶结接触模型植入离散元软件,模拟了砂岩的直接剪切试验,对砂岩的宏、微观特性进行详细的分析。模拟结果表明:砂岩的直剪数值试验过程可以分为3个阶段,即线性剪切阶段、应力衰减阶段及残余强度阶段;剪切过程中,外界做功主要转化为颗粒摩擦耗能,并始终存在着能量守恒;胶结破坏数目会随着剪应变的增大而增加,胶结拉区破坏数目大于胶结压区破坏数目,胶结破坏形式均由弯破坏形式主导;裂纹首先从剪切面两端产生,拉区裂纹产生于剪切面中间,向剪切面两端以及上、下侧扩展,压区裂纹从剪切面两端向中间扩展,最后拉区裂纹与压区裂纹相互贯通布满整个剪切面,在空间上最终形成一个截面呈椭球状的分布域;本文的直剪数值试验结果与砂岩剪切试验结果基本一致。In order to investigate the shear mechanics of deep rock masses under high ground stress,a semi-empirical and semi-theoretical bonded contact model was implanted into discrete element software to simulate the direct shear test of sandstone,through which the macroscopic and microscopic characteristics of sandstone were analyzed in detail. The simulation results show that the direct shear test of sandstone can be divided into three stages: the linear shear stage,the stress decreasing stage and the residual strength stage. During the shearing process,the external force is mainly converted into particle frictional energy,so energy conservation always exists in the system. The number of bond failures increases with the increasing of shear strain. The number of bond failures in the tensile zone is greater than that in the compressive zone. And the failure modes of bond are dominated by bending failure mode. Cracks start to generate from both ends of the shear plane,cracks of tensile zone first occur in the middle of the shear plane and then propagate to the ends,upper and lower side,whereas the cracks of compressive zone propagate from both ends of the shear plane to the middle. Then,the cracks of tensile and compressive zone connect and penetrate through the entire shear plane,form a distribution domain with an ellipsoidshaped section. The results of direct shear numerical tests of sandstone are consistent with those of the laboratory test.

关 键 词：砂岩 裂纹扩展机理 高地应力 离散单元法 直接剪切试验 

分 类 号：TU45[建筑科学—岩土工程]