非饱和岩土材料的固流转化数值模拟

Numerical simulation of solid-state conversion of geomaterials

为对非饱和岩土材料的固流转换进行研究,首先介绍了一个非饱和岩土材料固流转化模型。该模型由一个水力耦合弹塑性模型、一个宾汉黏性模型和一个固流转化准则组成,它可以在统一框架内描述非饱和岩土破材料坏前后的固流力学性质。与此同时,还基于拉格朗日积分点有限元法(FEMLIP)提出求解水力耦合问题的方法,并采用平衡方程和连续方程,将固流转化模型植入一个FEMLIP数值软件中。为了精确处理非饱和岩土问题,该模型还引入了毕肖普有效应力及水分特征曲线。最后,通过模拟一个启发式渗流实验,定性地验证了该模型的可靠性和发展潜力,通过准确的物理参数,使用FEMLIP方法和该固流转化模型对真实泥石流进行分析预测是可行的。

The paper describes a proposed unified hydro-elasto-plastie model with a solid-fluid transition. The model associates a hydro-elasto-plastic model for partially saturated geomaterials, a Bingham＇s viscous law,and the transition criterion between solid and fluid states. The model describes both solid and fluid behaviors of partially saturated geomaterials in a unified framework. In addition, this paper describes a novel Pinite Element Method with Lagrangian Integration Points （FEMLIP） formulation for solving hydro-mechanical problems. Based on the equilibrium equation of momentum and the continuity equation of water flow, the formulation was developed and implemented in a FEMLIP tool. Bishop＇s effective stress expression and proper water retention diagrams were taken into account. A heuristic column and real rainfall-induced mudflows were also simulated and analyzed in this study. The permeability effects of partially saturated soil and the effective cohesion were considered, which included consideration of the entire mudflow process. The results were proven satisfactorily in a qualitative fashion.