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软化塑性模型的常规有限元数值分析结果严重依赖网格尺寸,而非局部塑性模型是解决这一问题的有效方法。但现有非局部模型仅能用于von Mises准则,无法用来进行一般软化土体渐进破坏分析。提出了一种改进的针对非局部模型的全隐式应力回代迭代计算方法,该方法具有在迭代计算过程中逐步确定弹塑性点的特点,克服了现有算法误差较大及不稳定的缺点。将非局部理论推广到Mohr-Coulomb塑性模型中,使其能用来分析土体稳定性问题。采用局部和非局部模型对两个土体稳定问题,包括条形基础承载力问题和三角形荷载下边坡稳定问题进行渐进破坏分析,数值计算结果表明该方法可以消除软化塑性有限元计算的网格敏感性,起到了正则化的效果。
The conventional finite element numerical analysis of plasticized plastic model relies heavily on the mesh size, rather than the local plastic model is an effective way to solve this problem. However, the existing non-local model can only be used for von Mises criterion, which can not be used for progressive destructive analysis of general softening soil. An improved method of iterative total implicit stress iteration for nonlocal models is proposed. This method has the characteristic of gradually determining the elastic-plastic points during the iterative calculation and overcoming the shortcomings of large and unstable errors of the existing algorithms . The nonlocal theory is extended to the Mohr-Coulomb plastic model, which can be used to analyze soil stability problems. The local and non-local models are applied to the progressive failure analysis of two soil stability problems, including the strip foundation bearing capacity and slope stability under triangular load. The numerical results show that this method can eliminate the grid-sensitive Sex, played a regularized effect.