基于各向异性界面单元的岩石端部效应数值模拟  

Numerical Silulatuon on End Effect of Rock Specimens Based on the Anisotropic Interface Element Model

作　　者：梁正召[1] 吴宪锴 唐世斌[1] 王文琦 LIANG Zhengzhao;WU Xiankai;TANG Shibin;WANG Wenqi(State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,China;Research and Development Center of Highway Maintenance Technology,Transportation Planning and Design Institute of Liaoning Province,Shenyang 110111,China;Liaoning Datong Highway Engineering Limited Company,Shenyang 110111,China)

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024 [2]辽宁省交通规划设计院公路养护技术研发中心,辽宁沈阳110111 [3]辽宁大通公路工程有限公司,辽宁沈阳110111

出　　处：《应用基础与工程科学学报》2018年第3期526-537,共12页Journal of Basic Science and Engineering

基　　金：国家重点基础研究计划973项目(2014CB047100);国家自然科学基金项目

摘　　要：岩石端部效应是岩石力学实验的一个难以回避的问题.通常观点认为水平摩擦力、试样形状效应、加载垫板、试样的刚度比等因素是导致端部效应的主要原因,但这4种因素如何影响试验结果,目前尚不明确.本文建立一种考虑接触面不同的法向与切向刚度的各向异性界面单元,模拟试件与加载端部的接触界面力学行为,探讨切向刚度系数K_s、法向刚度系数K_n、加载垫板的刚度K_p的影响,并考虑到试样的形状效应,改变试样高宽比,系统研究不同因素作用下岩石的端部效应及破裂模式.模拟结果表明,K_s的增加使端部由拉应力变为压应力,破坏形式由纵向劈裂转变为斜面剪切破坏;K_p的的影响与K_s的影响类似,K_n对岩石力学性能影响相对较小;试样形状的改变也同样影响端部受力和破坏模式,且端部越粗糙,高宽比的影响越明显.The end effect of rock is a complicated problem in rock mechanics experiments. It is generally recognized that horizontal friction,depth-width ratio,stiffness ratio of loading plate to the specimen are the main influencing factors resulting in the end effect,yet how these factors change the experimental results is not clear. In this article,different normal and tangential stiffness in the contact surface was considered to establish an anisotropic interface element with certain mechanical strength and geometric thickness. The mechanical behaviour of the interface of the specimens,the loading end,and the function of tangential stiffness coefficient Ks,normal stiffness coefficient Kn,the stiffness Kpof the platen were simulated to study the end effect and failure mode systematically. The simulation indicates that the end stress changed from tensile stress to compressive stress with the increase of Ks,and the failure mode varied from longitudinal splitting to diagonal shear failure. Kphad similar effects as Kswhile Knhad relatively less influence on the failure strength. The specimen shape also had significant influences on the strength and failure modes of the rock specimens. Additionally,the effect of depth-width ratio was enhanced when the loading end becomes rougher.

关 键 词：单轴加载 端部效应 接触界面 节理单元 形状效应 

分 类 号：TD353[矿业工程—矿井建设]