考虑土体基质吸力刚性挡墙基坑抗倾覆稳定性分析

Anti-overturning Stability Analysis of Rigid Wall Considering Soil Matric Suction

地表降雨入渗对基坑周边土体有明显影响,进而引起基坑抗倾覆稳定性改变。基于非饱和土的平面应变抗剪强度统一解,考虑非饱和土强度的中间主应力效应,引入地下水位线以上非饱和土体基质吸力的空间分布,推导得到降雨入渗条件下的基坑挡墙抗倾覆稳定系数。对比分析了不同基质吸力分布模式对基坑抗倾覆稳定性的影响,研究了地下水位,降雨入渗强度,挡墙嵌固深度,土体内摩擦角等因素对基坑抗倾覆稳定性的影响。结果表明,降雨入渗降低了土体基质吸力;地下水位线的降低可以有效提高基坑抗倾覆稳定性;考虑中间主应力效应可以更加发挥非饱和土体的强度潜能;基质吸力及其分布形式对抗倾覆稳定性有显著影响。

The infiltration has a significant effect on the soils around the foundation pit,having a great influence on the anti-overturning stability of foundation pits. Based onthe unified solution of shear strength for unsaturated soils under the plane strain condition,considering the intermediate principal stress effect and the distribution of the suction stress above the groundwater level,the anti-overturning stability coefficient underrainfall infiltration is derived. The anti-overturning stability under effects of different suction distribution modes is compared and analyzed,and the influence of groundwater level,rainfall infiltration intensity,retaining wall embedded depth,and friction angle are researched. The result shows that,rainfall infiltration makes the soil matricsuction reduce,and the reduction of groundwater level can effectively improve the anti-overturning stability of foundation pit,the greater strength in comparing to the saturated soil could be utilized considering the intermediate principal stress effect,and the matrix suction and its distribution has a significant effect on the stability of overturning.