基于非线性破坏准则的地基临界荷载计算

摘要

In order to calculate the critical load of strip footing under a nonlinear Mohr-Coulomb failure criterion, the variables ct and φt are created by a generalized tangential technique, the equilibrium equation of total stress at any point in the foundation is established according to the limit equilibrium condition of subsoil, and a iterative calculation method of critical load p1/4 of the foundation is presented.Through an sample, the effect of different m on the critical load of the foundation when the strength parameters σt, c0 and footing embedded depth d take different values is calculated.The results show that nonlinear failure criterion has important influence on the critical load and the location of plastic zone in the foundation.Using nonlinear Mohr-Coulomb failure criterion could decrease the calculated value of the critical load, and the location of plastic zone of the foundation is closer to the center line when zmax=b/4.The introduction of nonlinear failure criterion can better conform to the foundation reality and accurately evaluate the bearing capacity.%为计算基于非线性Mohr-Coulomb破坏准则影响下的条形基础地基临界荷载,通过"切线法"引入变量ct和φt,根据地基土体的极限平衡条件建立地基中任意一点处的应力平衡方程,给出了地基临界荷载p1/4的迭代计算方法,并结合算例计算分析了强度参数σt,c0和基础埋深d取不同值时非线性参数m对地基临界荷载的影响.结果表明,非线性破坏准则对地基临界荷载和塑性区的位置有重要影响;引入非线性破坏准则会明显减小临界荷载的计算值,并且zmax=b/4时的地基塑性变形区域更靠近于基础内侧.引入非线性破坏准则更符合地基实际,可更准确地评价承载力的大小.