降雨入渗条件下非饱和路堤变形与边坡的稳定数值模拟

Numerical simulation for unsaturated road-embankment deformation and slope stability under rainfall infiltration

对于常常处于非饱和状态的路堤在降雨入渗条件下变形问题的数值模拟研究,由于涉及到非饱和土力学,一直是个热点和难点。现有的强度折减有限元法一般仅对强度指标进行折减,但折减后得到的路堤变形场与实际变形场存在一定差异。论文分析认为,在降雨入渗影响下非饱和路堤不仅强度参数会降低,而且变形参数也会随着应力水平和强度参数的变化而变化。采用基于变模量的弹塑性强度折减法,对不同降雨入渗深度下路堤的变形规律进行数值模拟,并与室内模型试验结果进行比较;同时采用强度折减法和极限平衡法中的Bishop法,分析了不同降雨入渗深度对非饱和路堤稳定性和滑弧变化特征的影响规律。

Owing to involving to unsaturated soil mechanics,numerical simulation for deformation of unsaturated road-embankment under rainfall infiltration is still a difficult point.The present strength reduction finite element methods usually only reduce strength parameters,which result in the deformation fields of road-embankments are different from the practical ones.This paper holds that under rainfall infiltration,not only the strength parameters of road-embankment soils will reduce,but also the deformation parameters will also change with the changing of soils stress levels and strength parameters.Using the developed FLAC program by authors,the numerical simulation for a high road-embankment deformation under different rainfall infiltration depths are conducted;and the results of numerical calculation are compared with those of the laboratory model tests.Then the influence law of rainfall infiltration depths on the road-embankment slope stability and sliding arc changing characteristics are analyzed by strength reduction finite element methods and limit equilibrium method（Bishop method）.