淤泥质软土基坑边坡稳定性分析及其加固方案研究

Analysis of Foundation Pit Slope Stability Excavated in Mucky Soil and the Reinforcement Technology

明挖隧道施工的淤泥质软土基坑在开挖过程中,其部分断面处的基坑边坡易出现较大的地表累积沉降和边坡水平位移,会严重影响到工程建设的安全性。采用有限元强度折减法对案例工程上述断面处的基坑边坡进行了稳定性分析,得出该边坡的安全系数仅为0.63,并找到潜在的滑动面及其破坏模式。在上述研究的基础上,提出了2种加固方案。经分析,在坡脚注浆、设置钢板桩和堆土反压加固方案的加固效果不理想,在坡脚注浆并设置抗滑桩加固方案能显著提高边坡稳定安全系数,能有效控制地表沉降和边坡面位移。

In the process of foundation pit excavation,large ground surface settlement and slope horizontal displacement are frequently found at some sections,which seriously affect the safety of construction.In this paper,the strength reduction based FEM is used to study the slope stability.The result shows that the safety factor of the slope is only 0.63,the potential sliding surface and the failure mode are detected simultaneously.According to above analysis,two different slope reinforcement schemes are proposed.One option is to reinforce the slope by grouting the slope foot,installing steel sheet pile and stacking passive soil,but the effect is not idea.Another is to reinforce the slope by grouting the slope foot and installing antislide piles,it is more effective in improving the safety factor of slope stability,controlling ground surface subsidence and displacement of slope surface.