硬粘土基坑开挖土压力变化规律分析

Analysis of pressure change law of hard-clayey foundation pit

为了研究硬粘土基坑开挖土压力变化规律,利用数值模拟软件FLAC3D,研究了硬粘土基坑在无支护开挖过程中主动区、被动区土压力以及坑脚处集中应力的变化规律。模拟结果表明:经典Rankine理论不适合于硬粘土土层土压力的分析研究;基坑开挖主动区上压力与深度呈正定线性关系;基坑被动区土压力在坑脚附近形成近似矩形的应力集中区域;位于开挖侧面上的突变应力,存在于1．0-1.2倍开挖深度的土层区域内,其值是相应深度处静止土压力的1．0-1.8倍。

In order to research the pressure change law of hard-clayey foundation pit, the law of soil pressure in both active and passive areas and the focus stress at the foot of the pit in the excavation process of one hard-clayey foundation pit is studied with FLAC^3D.The numerical simulation results show that firstly, the traditional Rankine Theory can＇t be simply applied to the analysis of hard-clayey soil; secondly, the soil pressure in active areas presents a linear relationship with the depth; at the same time, in passive areas there exits a similar rectangular range of focus stress at the foot of the pit; finally, the peak value of focus stress on the vertical excavation surface is about 1.0-1.8 times of the static soil pressure at the same level and is located in the range of 1.0-1.2 times of the corresponding excavation depth.