摘要
天然土体一般具有原始结构,在其结构被破坏前后会表现出不同的力学特性,这些特性很难用传统的弹塑性理论来进行模拟。本文提出能够反映胶结和吸力两个因素影响的结构性黄土本构模型,采用损伤函数和屈服函数反映天然黄土的湿陷变形。这一模型把变形过程中的天然黄土看作不同大小土块的集合体,总的变形由土块的弹性变形、土块之间滑动引起的塑性变形和土块破碎引起的损伤变形三部分组成。塑性变形常用屈服函数描述,损伤变形则引入一种类似的损伤函数加以描述。本文在严格的非饱和土力学理论的基础上,开发相应的有限元程序,模拟一个黄土渠道典型断面的湿陷变形,分析了黄土渠道浸水变形的基本特性。
Natural soils may exhibit different behaviors before and after the damage of structure and their behaviors cannot be properly modeled by traditional elasto-plastic theory. A constitutive model for structural loess taking account of both suction and cementation is proposed. In this model the damage function is defined and used in parallel with the yield function to predict the deformation of natural loess during wetting. The natural loess is regarded as an assembly of lumps with different sizes, and it is assumed that the total deformation consists of three parts, i.e. elastic deformation of lumps, plastic deformation due to sliding between lumps and irrecoverable deformation due to crushing of lumps. Yield function is introduced to describe the plastic deformation and a new damage function is proposed to describe the additional deformation due to the damage of soil structure. Based on the strict theory for unsaturated soil, a program for calculation of finite element method is developed to simulate the deformation of a loess ditch during immersion. The calculation result is reasonable in reflecting the actual behaviors.
出处
《水利学报》
EI
CSCD
北大核心
2005年第3期309-313,320,共6页
Journal of Hydraulic Engineering
基金
水利部重点基金项目(SZ9807)
中国博士后科学基金资助项目
关键词
湿陷性
本构模型
非饱和土
wetting
collapsible loess
constitutive model
unsaturated soil
