极限上限分析中“切线法”引入非线性破坏准则的探讨  

Discussion on Generalized Tangential Method Led in Nonlinear Failure Criterion in Upper Boundary Limit Analysis

作　　者：赵炼恒[1] 李亮[1] 但汉成[1] 罗苏平[1] 任东亚[1] 

机构地区：[1]中南大学土木建筑学院,长沙410075

出　　处：《长江科学院院报》2010年第8期34-39,共6页Journal of Changjiang River Scientific Research Institute

基　　金：西部交通建设科技项目(2006318802111);中南大学优秀博士学位论文扶植项目(2008yb004);铁道部科技研究开发计划重点资助项目(2008G032-3);湖南省交通厅科技项目(2007-29)

摘　　要：基于极限分析上限法,讨论了"切线法"引入非线性M-C破坏准则时采用"初始切线法"和"外切线法"对边坡临界高度、地基承载力、主动土压力3个经典土力学问题的影响,用以分析"外切线法"引入非线性破坏准则对分析岩土问题的合理性和有效性。研究表明:非线性参数对土工结构的安全性有重要影响,恰当引入岩土材料的非线性破坏特性更加符合工程实际;基于上限法通过"初始切线法"引入非线性破坏准则是众多上限解答的一个上限解答,特定条件下能够获得较好的上限解,但随着非线性参数m的增大由此引起的误差也越来越大,采用"外切线法"更具有效性和合理性。On the basis of the upper boundary limit analysis theorem and nonlinear M-C failure criterion, three classical soil mechanics problems including the uhimate bearing capacity of a rough strip foundation, the critical height of a slope and the active soil pressure were studied by means of generalized tangential technique and the ki- nematic approach of limit analysis theory. The rationality and feasibility of the generalized tangential method and the inceptive tangential method were analyzed. From the numerical results, it can be seen that the nonlinear failure parameter exerts a significant effect on the safety of the geotechnical structure, and leading-in a proper nonlinear failure character of geo-materials more agrees with the engineering practice. The case study and comparative analy- sis show that a better solution could be achieved by means of the inceptive tangential method under specific condi- tions, but the larger the nonlinear coefficient is, the bigger the deviation caused by the inceptive tangential method is. The generalized tangential method possesses the rationality and feasibility obviously.

关 键 词：土力学 非线性M—C破坏准则 极限上限法 切线法 

分 类 号：TU432[建筑科学—岩土工程]