基于随机场的非饱和土固结分析

doi:10.16183/j.cnki.jsjtu.2014.11.005

摘要/Abstract

摘要：

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COV_E对沉降的均值和标准差的影响都很大．COV_E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．

关键词: 空间变异性, 随机场, 非饱和土, 流固耦合, 蒙特卡罗法

Abstract:

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 significantly affected by the coefficient of variation of Young's modulus, and COV_E. When COV_E 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 δ_ln_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 δ_ln_E. In general, the effect of spatial variability of k_s is much less significant than that of elastic modulus, which mainly affects the unsaturated consolidation in process.

Key words: spatial variability, random field, unsaturated soil, hydro-mechanical coupling, Monte Carlo simulation

中图分类号:

TU432

程演, 张璐璐, 张磊, 王建华. 基于随机场的非饱和土固结分析[J]. 上海交通大学学报, 2014, 48(11): 1528-1535.

CHENG Yan, ZHANG Lu-lu, ZHANG Lei, WANG Jian-hua. Coupled Consolidation in Unsaturated Soils Based on Random Field Theory[J]. Journal of Shanghai Jiao Tong University, 2014, 48(11): 1528-1535.

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参数	数值
ρ_w／（kg·m^-3）	1　000
g／（m·s^-2）	9.801
ρ_s／（kg·m^-3）	2.65×10³
β_w／（m²·kN^-1）	5×10^-7
α_c	1.0
n	0.45
E／MPa	19
k_s／（μm·s^-1）	34.7
ν	0.3
S_{w r}	0.07
α	1.0
β／m^-1	1.74
ε	2.5
a／m^-1	6.67
b	5.00