非饱和土基坑刚性挡墙抗倾覆设计与参数分析

Anti-overturning design and parametric analysis for rigid retaining wall of foundation pit in unsaturated soils

针对非饱和土基坑刚性挡墙提出其抗倾覆计算的基本假定,推导基质吸力均匀分布和线性减小2种情况下满足不同抗倾覆稳定系数的埋置深度方程,并对新定义的抗倾覆埋置系数进行参数影响特性分析。研究结果表明:基质吸力及其分布、吸力角和有效抗剪强度参数对抗倾覆埋置系数的影响显著,抗倾覆埋置系数随基质吸力、吸力角和有效抗剪强度参数的增加不断减小甚至为零;忽略基质吸力的饱和土基坑挡墙抗倾覆设计过于保守,线性分布时基质吸力的影响不如均匀分布时显著,应合理假定基质吸力分布并采取工程措施确保其稳定存在。

Some basic assumptions for the anti-overturning calculation were firstly made for rigid retaining wall of foundation pit in unsaturated soils; then the embedment depth equations to meet different anti-overturn stability coefficients were derived at the matric suction with both uniform distribution and linear distribution; finally, parametric investigations about a new definition anti-overturning buried coefficient were discussed. The results show that the influence of matric suction and its distribution, suction angle and effective shear strength parameters on the anti-overturning buried coefficient is significant; the anti-overturning buried coefficient decreases and even becomes zero with the increase of the matric suction, suction angle and effective shear strength parameters; the anti-overturning design for foundation pit wall with saturated soils ignoring matric suction is too conservative; the influence of matric suction with linear distribution is not as remarkable as that of matric suction with uniform distribution; the distribution of matric suction should be reasonably assumed and some engineering measures are needed to ensure its stability.