强度折减法中非均质层状土坡失稳判据适用性  

Applicability Research on Instability Criterions for Inhomogeneous Layered Slope Using Strength Reduction Method

作　　者：贺俊[1] 史俊涛 黄璐[1] 孔思丽[3] 

机构地区：[1]西南石油大学土木工程与建筑学院,四川成都610500 [2]天门市建筑业管理处,湖北天门431700 [3]贵州大学土木工程学院,贵州贵阳550025

出　　处：《人民黄河》2014年第12期122-125,共4页Yellow River

基　　金：国家自然科学基金青年科学基金资助项目(51208443)

摘　　要：通过对各种D-P准则进行系统深入的分析,提出了一种在非均质边坡中实现D-P系列屈服准则间相互转换的方法,针对一个具体的非均质边坡建立弹塑性有限元分析模型,采用强度折减法计算得出各D-P准则下的安全系数,与极限平衡法计算结果进行对比分析,验证了该方法的可行性。在此基础上对强度折减法中各种失稳判据在非均质边坡中的适用性和不同网格尺寸对非均质边坡安全系数计算精度的影响进行研究。结果表明:以塑性区贯通和特征部位位移突变作为失稳判据,通过对比不同强度折减系数下的位移场和塑性区特性,可以减弱非确定因素带来的影响,其计算出的安全系数与极限平衡法所得结果较为接近,而采用数值计算不收敛作为失稳判据所得结果误差较大,不满足工程精度要求。因此,采用强度折减法对非均质土坡进行稳定性分析时,建议使用特征部位位移突变结合塑性区贯通作为失稳判据。Through focusing on analyzing systematically and deeply on Drucker-Prager yield criterion,the conversion method of different Drucker-Prager criterion in inhomogeneous slope was put forward. An elastic-plastic FEM for specific inhomogeneous slope was established and the safety factor was calculated by using SSR technique based on the Drucker-Prager yield criterion. Comparing with the solution of traditional limit equilibri-um method,the proposed method was proved to be feasible in inhomogeneous slope. On this basis,the applicability of different instability criterions in inhomogeneous slope and the effect of mesh size on calculating precision of safety factor were studied. The results show that the effect of uncertain conditions for safety factor can be weakened by contrast to displacement field and characteristics of plastic zone under different strength reduction co-efficients and the computing result and potential slip surface obtained based on displacement mutation at certain characteristic position is fairly close to the solution gained by traditional limit equilibrium method,while the results based on the convergence of numerical computations giving large de-viation are not fit for engineering precision. It is suggested that the instability criterion which using displacement mutation at certain characteristic position combing with plastic zone juncture should be more reasonable and applicable than the convergence of numerical computations when inhomo-geneous slope is analyzed.

关 键 词：非均质层状土坡 失稳判据 网格尺寸 屈服准则 稳定性分析 适用性研究 

分 类 号：TU457[建筑科学—岩土工程]