不同边界条件下土石混合体破坏机制研究  

A study of the failure mechanism of rock and soil associate under different boundary conditions

作　　者：范永波[1] 李世海[1] 侯岳峰[1] 冯春[1] 

机构地区：[1]中国科学院力学研究所,北京100190

出　　处：《水文地质工程地质》2013年第3期48-51,68,共5页Hydrogeology & Engineering Geology

基　　金：973项目(2010CB731506);国家自然基金项目(11002146)

摘　　要：土石混合体是非均匀、非连续的,在外力作用下,其内部应力分布是不均匀的,其真正的边界条件是等应力边界条件。现有的土力学实验机都是刚性边界加载,即按等位移边界条件加载,不适用于研究非均匀材料。基于此自行研制了等应力边界加载实验机,通过采用柔性压头和柔性底座施加等应力边界条件,研究两种边界条件下土石混合体抗剪强度参数的差异,同时采用课题组自行研发的CDEM(Continuum-based Discrete Element Method)计算软件,开展了相应的数值计算,结果表明,传统的等位移边界条件所得不均匀地质体参数明显大于同等条件下等应力边界条件所得参数(约20%),是偏不安全的。RSA(rock and soil associate) is inhomogeneous and discontinuous,and the stress distribution inside the materials is uneven while external forces are applied on them.For these materials,the real boundary condition is the equal stress boundary condition.The existing soil mechanics testing machines are loaded by rigid boundaries,i.e.,the equal displacement boundary loading.This testing machine is not suitable for inhomogeneous material.In order to eaxime the mechanical behavior of RSA or fractured rock,a new type of triaxial compressive test machine with equal stress boundary loading is developed,using flexible head and base,imposing the equal stress boundary conditions.Difference in shear strength parameters of RSA under two boundary conditions are studied.And,we carried out numerical calculation with the software CDEM.The results show that the parameters obtained from the equal displacement boundary loading is 20% greater than the parameters obtained from the equal stress boundary condition and they tend to be unsafe.

关 键 词：土石混合体 不同边界条件 三轴实验 

分 类 号：TU411[建筑科学—岩土工程]