石质坑底的基坑边坡设计及其滑移线选取研究

Design for the Slope of Foundation Pit with Rock Bed and Selection of the Slipline

本文在分析两次基坑边坡塌方事故的基础上,总结了两个边坡的共性。分别选取直线和圆弧线作为滑移线,利用条分法进行稳定性演算,并与有限元强度折减法求得的安全系数进行比较,发现直线条分法与强度折减法得到安全系数相近,都大于圆弧条分法得到的安全系数,而且有限元法得到的塑性贯通区近似直线而非圆弧线,充分证明了坑底为岩石、边坡部分为土层的基坑边坡,其失稳滑移线应取直线。最后依据两次事故的经验,针对该类边坡的支护设计提出一些建议。

Based on the analysis of the reasons for the two landslides of foundation pit, the commonness of the slopes is summarized. It could be found that the slip-line of the slope of the foundation pit which is soil slope with rock bed should be straight line. The Safety factor is analyzed by using FEM with strength reduction, and the conclusion is proved. Some suggestions are given for the design of this kind of slope.