砂土初始孔隙比空间变异性对其力学特性及破坏模式的影响分析

现有研究大多采用简单的摩尔库伦模型针对土的空间变异性对边坡或基础的安全系数或失效概率做计算分析.事实上临界状态本构模型,如SIMSAND,能更准确地反映土的应力-应变关系.为此,本文采用SIM-SAND模型,针对砂土初始孔隙比的空间变异性对其力学特性及破坏模式的影响做详细分析,算例采用简单的室内平面应变双轴试验,分为松砂排水、密砂排水、松砂不排水和密砂不排水四种情况.每一种情况均采用蒙特卡罗方法进行初始孔隙比的随机分布生成,并做大量计算,以此来分析初始孔隙比的不均匀性对剪切带生成和破坏模式和竖向承载力发展及其概率密度分布的影响.

Influence of spatial variability of initial void ratio on the mechanical response and failure mode of sand

Most of the existing studies use simple More-Coulomb model to analyse the influence of spatial variability of soil on the factor of safety or the failure probability of the slope/foundation.In fact,the critical state constitutive model,such as SIMSAND model,can more accurately describe the stress-strain relationship of soil.For this reason,this paper adopts the SIMSAND model to make a detailed analysis of the influence of the spatial variability of the initial void ratio.A simple plane strain biaxial test was simulated as a calculation example with four cases:(i) drained condition and loose sand,(ii) drained condition and dense sand,(iii) undrained condition and loose sand,and (iv) undrained condition and dense sand.In each case,the Monte Carlo method is used to generate the random filed of the initial void ratio,and a large number of calculations are performed to analyse the influence of the inhomogeneity of the initial void ratio on the development of the shear band,the vertical bearing capacity and the probability density distribution of the vertical bearing capacity.