基于非线性Mohr-Coulomb准则的刚性条形基础下伏孔洞承载特性变分分析  

Variational analysis of bearing characteristics of the cavity under the rigid strip foundation based on the nonlinear Mohr-Coulomb failure criterion

作　　者：李亮[1] 石鹤扬 曾中林 胡世红[1] LI Liang;SHI Heyang;ZENG Zhonglin;HU Shihong(School of Civil Engineering,Central South University,Changsha 410075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075

出　　处：《铁道科学与工程学报》2018年第12期3089-3096,共8页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51478477)

摘　　要：基于非线性Mohr-Coulomb(MC)破坏准则以及相关流动法则,构建刚性条形基础下伏孔洞冲切破坏机制;结合变分原理,推导出刚性条形基础下伏孔洞冲切破坏曲线的表达式,进而得到冲切破坏时的极限承载力。分析刚性基础随岩土体参数变化时,冲切破坏极限承载力的变化情况和破坏模式。研究结果表明:非线性系数m的大小对刚性基础极限承载力的影响较为显著。随着非线性系数m的增大,刚性基础极限承载力不断减小;极限承载力随岩土体初始黏聚力C0的增大而增大,随岩土体重度以及抗拉强度的增大而减小。岩溶顶板冲切破坏宽度随初始黏聚力C0的增大、重度的减小以及抗拉强度的减小而增大。Based on the nonlinear Mohr-Coulomb failure criterion and the associated flow rule,a punching sear failure mechanism of soil under the rigid foundation was constructed,the expression of punching failure curve was deduced according to the variation principle,and then the ultimate bearing capacity was obtained.The influence of ultimate bearing capacity of the rigid foundation and failure mode were analyzed with the soil parameters changing.The results show that the nonlinear parameter m has significant influence on the ultimate bearing capacity,and it will decrease constantly with the improvement of nonlinear parameter m,the ultimate bearing capacity will increase with the improvement of the initial cohesive force C0 of soil,but will decrease with the improvement of the densityγand tensile strengthσt of soil.The failure width of karst roof will increase with the improvement of the initial cohesive force C0 of soil,but will decrease with the improvement of the densityγand tensile strengthσt of soil.

关 键 词：冲切破坏 极限承载力 非线性MC准则 极限分析上限定理 变分分析 

分 类 号：TU470[建筑科学—结构工程]