敏感环境下基坑数值分析中土体本构模型的选择  

Selection of soil constitutive models for numerical analysis of deep excavations in close proximity to sensitive properties

作　　者：徐中华[1] 王卫东[1] 

机构地区：[1]华东建筑设计研究院地基基础与地下工程设计研究所,上海200002

出　　处：《岩土力学》2010年第1期258-264,326,共8页Rock and Soil Mechanics

基　　金：上海市科委科技攻关重点项目(No.08201200900);上海市科委优秀学科带头人计划项目(No.07XD14206)

摘　　要：数值分析已成为敏感环境下基坑工程分析的最重要手段,其关键是选择合适的土体本构模型和计算参数。在分析了岩土数值分析中常用土体本构模型特点的基础上,通过算例较系统地对比了各类模型在基坑开挖数值分析中的适用性。敏感环境下的基坑工程需重点关注墙后土体的变形,从满足工程需要和方便实用的角度出发,建议采用能考虑黏土的塑性和应变硬化特征、能区分加荷和卸荷且刚度依赖于应力水平的硬化类弹塑性模型,如MCC模型和HS模型进行分析。具体工程实例的分析,表明了硬化类弹塑性模型在敏感环境下基坑开挖数值分析中的适用性。Numerical analysis has become the most important method for analyzing deep excavations in close proximity to sensitive properties. One of the key problems in a numerical analysis is to select proper soil constitutive models and their corresponding parameters. The possibilities and limitations of a limited number of soil constitutive models frequently used in geotechnical numerical simulations were discussed. The suitability of these constitutive models applied to numerical analysis of deep excavations in close proximity to sensitive properties was compared. As ground movement control is a key design consideration in excavations adjacent to sensitive properties, the constitutive model must be able to predict realistic distributions of movement around retaining structures. It was recommended to use strain hardening plastic constitutive models such as modified Cam clay （MCC） model and Plaxis Hardening Soil （HS） model to simulate excavations in close proximity to sensitive properties because they can reflect many important features of soil which are important in excavation simulations. These features include plasticity, strain hardening difference between loading and unloading stiffness, and stress dependent stiffness. The results of the simulation of a deep excavation illustrate the capabilities of the strain hardening plastic constitutive model in the numerical analysis of deep excavations.

关 键 词：基坑 敏感环境 数值分析 本构模型 

分 类 号：TU476[建筑科学—结构工程]