基于随机场的非饱和土固结分析

Coupled Consolidation in Unsaturated Soils Based on Random Field Theory

基于随机场理论,采用协方差矩阵分解随机场模拟和蒙特卡罗方法相结合的方法,建立非饱和土固结的流固耦合随机有限元模型,研究弹性模量和饱和渗透系数的空间变异特性对非饱和土固结的影响.结果表明,弹性模量变异系数COVE对沉降的均值和标准差的影响都很大.COVE增大,沉降的均值和标准差相应增加,说明弹性模量的空间变异性可显著增大沉降预测的不确定性.弹性模量的竖向相关距离越小,空间平均效应越大,超孔隙水压力和沉降的标准差越小,尤其在土层厚度小于相关距离时影响较为显著.饱和渗透系数的空间变异性对非饱和土固结的影响较弹性模量小得多,且主要影响固结中间过程.

Based on the random field theory, a random finite element model of coupled unsaturated consolidation in spatial random soils was established using the covariance matrix decomposition method and Monte Carlo simulation method. The effects of spatial variability of Young＇s modulus and saturated permeability were investigated. The results show that the mean and standard deviation of the settlement are significant ly affected by the coefficient of variation of Young＇s modulus, and COVE. When COVE increases, the mean and standard deviation of the settlement increase, which means the uncertainty of the settlement are increased due to the spatial variability of Young^s modulus. When the correlation length of Young＇s modulus δIn E decreases, the standard deviation of excess pore water pressure and the surface settlement decrease due to the increased spatial averaging effect. The spatial averaging effect is more significant when the thickness of soil layer is smaller than δIn E, In general, the effect of spatial variability of ks is much less significant than that of elastic modulus, which mainly affects the unsaturated consolidation in process.