基于FLAC^(3D)软土路堤稳定性分析

Stability Analysis for Soft Soil Embankment Based on FLAC^(3D)

在软土路基修筑高速公路时路堤填筑至极限高度后经常出现路堤失稳情况。结合四川省遂宁-资阳-眉山高速公路软基监测项目,采用FLAC3D强度折减分析方法对典型路段进行路堤分级加载稳定性分析,结果表明:该法能模拟路堤塑性区发展过程,塑性应变自堤趾到堤肩贯通,呈带状分布,随填土高度的增加,塑性区向路堤中间及路基深部逐渐扩大,该塑性应变带即为相应的最危险潜在滑动面,呈圆弧形,其符合均质软土地基的滑动模式;该法考虑了模型的边界约束条件、初始地应力情况、岩土体的弹塑性变形及屈服,较刚体极限平衡完善,对边坡应力变形状态的综合稳定性分析比只给定安全系数更加重要。

There often appears embankment instability after filling over the boundary when building the express highway in soft soil subgrade.Here,based on Suining-Ziyang-Meishan Express Highway project,FLAC3D strength reduction method is used to calculate and analyze the stability of the subgrade with grading loading method.The results show that with this method,the development and damage evolution process of plastic zone could be simulated.The plastic strain would extend from the toe to the shoulder of the embankment with banded distribution.With the filling height increasing,the plastic zone would gradually expand to the middle and deep position of the embankment,this corresponding plastic zone is the most dangerous potential sliding plane with cylindrical arch,which is in line with the sliding mode of homogeneous soft soil subgrade.The method considers the boundary constraint conditions,initial geostress situation,and geotechnical engineering＇s elastic-plastic deformation and yield,being perfect than the rigid body limit equilibrium method.The comprehensive stability analysis on the slope deformation and stress state with this method is more important than the method only giving the security coefficient.