加筋砂土挡墙承载力及渐进性变形破坏的有限元分析方法

 为开发一种可以合理模拟加筋砂土挡墙承载力及渐进性变性破坏特征的数值分析方法，利用可考虑应变局部化的非线性弹塑性有限元法对一系列的加筋砂土挡墙模型试验结果进行从小变形到破坏的全过程数值分析。有限元分析中，砂土的本构关系采用基于修正塑性功的硬化–软化弹塑性模型，该模型引入应变局部化参数S用以描述砂土单元峰值以后的局部剪切破坏效果。模型试验结果与有限元计算结果比较表明：建议的非线性弹塑性有限元分析不仅可以较好地模拟分析加筋砂土挡墙基础底面的平均压力与沉降之间的关系，而且也能合理地模拟加筋砂土挡墙基础的剪切破坏的发生与发展状况、筋材的拉力以及挡墙面板的水平土压力分布等，它可以定量化地分析加筋砂土挡墙的渐进性变形破坏特征以及条带加筋材料的加固机制。

FINITE ELEMENT ANALYSIS METHOD ON BEARING CAPACITY AND PROGRESSIVE FAILURE OF REINFORCED-SAND RETAINING WALLS

In order to develop a rational numerical method for simulating the bearing capacity and progressive failure on reinforced-sand retaining walls and to gain a better insight into their associated reinforcing mechanisms，a set of model experimental results from well-controlled fully-instrumented load model tests of reinforced sand retaining wall are simulated by using of a nonlinear elasto-plastic finite element model considering strain localization. This constitutive model for sand is developed on the modified plastic strain energy concept. A strain localization parameter S is introduced in the constitutive model to describe the effect of shear banding after the peak strength of sandy element. It is found that the load-settlement relationships obtained from finite element method(FEM) analysis are generally in good agreement with those from the physical experimental results. The reinforcing mechanism and the progressive failure with developments of shear bands in reinforced sandy ground are also reasonably simulated by the proposed FEM analysis.