基于随机有限元的条形基础地基承载力概率分析

Probabilistic analysis for ultimate bearing capacity of a strip footing based on RFEM

为分析岩土力学特性空间变异对条形基础地基承载力的影响,建立了基于蒙特-卡洛方法的随机有限元模型,并利用Matlab和ABAQUS软件予以实现。将模型应用于条形基础地基极限承载力分析中,将土体的弹性模量和黏聚力视作随机变量,变异系数为0.3,进行了250次蒙特-卡洛模拟,获得了相应的地基极限承载力,并进行了概率统计分析,结果表明:地基土体的空间变异性通常会使得地基的承载能力降低;对于90%可靠度,若按变异系数0.3考虑,其承载力比均质情况低5.4%。

To reveal the effects of spatial variation of soil on ultimate bearing capacity of a strip footing,the random finite element model（RFEM）based on Monte-Carlo technology is presented,and is implemented by Matlab and ABAQUS.Then the model is applied to the analysis of the ultimate bearing capacity of a strip footing.The elastic modulus and cohesion of soil are considered as random spatial variables with the variation coefficient of 0.3 in this model,and 250 Monte-Carlo simulations are conducted.The corresponding ultimate bearing capacity of foundation are obtained and probabilistic statistical analysis is performed.The results show that the spatial variation of foundation soil usually leads to the reduction of the ultimate bearing capacity.For the reliability of 90% and the variation coefficient of 0.3,the bearing capacity is 5.4%lower than homogeneous case.