软土弹塑性损伤有限元分析

Finite Element Analysis of Elastoplastic Damage of Soft Soils

目的从损伤力学的角度,对传统的剑桥模型进行修正.方法通过建立一种土体损伤演化本构模型,研究常见的中心差分、Galerkin差分和全隐式差分等3种格式对Biot固结损伤有限元分析的影响变化规律.结果 3种差分格式对利用Biot固结损伤有限元计算路基沉降和孔压时的影响很小,得到的解答基本一致;但Crank-Nicholson差分、Galerkin差分和全隐式差分等这三种积分常数在影响材料损伤发展方面不同,Crank-Nicholson差分影响最小,而全隐式差分影响最大;在影响材料硬化率方面,影响规律与损伤发展影响规律正好相反,即Crank-Nicholson差分影响最大,而全隐式差分影响最小.结论修正后的模型对于解决包含此类问题的工程难题具有一定的参考价值.

The traditional cam clay model was modified based on the continuum damage mechanics firstly. Then, a damage constitutive model was proposed which could describe the evolution process of soil mass un- der external load, and the saturated soil consolidation problem was analyzed as an example to study the influ- ence of Crank-Nicholson, Galerkin and fully-implicit time difference schemes （TDS）on the finite element a- nalysis of roadbed using the theory of damage Biot＇s consolidation. The results show that the settlements and pore pressure calculated by three TDSs remain nearly same. However, the development curves of damage and hardening rate variables are affected seriously by three TDSs. The conclusions have certain reference values to the similar engineering.