考虑中间主应力的非饱和土边坡安全系数新解

New safety factor of slopes in unsaturated soils by considering the intermediate principal stress effect

基于非饱和土的平面应变抗剪强度统一解,考虑非饱和特性与中间主应力对土体强度的共同影响,利用瑞典简单条分法推导了非饱和土边坡安全系数的系列化新解,并探讨了中间主应力和基质吸力的影响特性。结果表明:中间主应力和基质吸力对非饱和土边坡安全系数的影响显著,安全系数随中间主应力效应和基质吸力的增加而大幅提高;边坡稳定性分析的强度理论效应明显,应重视强度准则的选取、加强基质吸力的监测和稳定控制。

Based on the unified solution of shear strength for unsaturated soils in the plane strain condition, this study analyzed the influence of both unsaturated characteristics and intermediate principal stress to soil strength. Additionally, we derived a new serialized safety factor of slopes about unsaturated soils based on the Swedish simple slice method. The effects of intermediate principal stress and matric suction were investigated and discussed. The results showed that the influence of intermediate principal stress and matric suction to safety factor of slopes in unsaturated soils is significant, and safety factor increases obviously with increase of the intermediate principal stress effect and matric suction. The results also revealed that the effect of strength theory on slope stability is remarkable. Consequently, attentions should be given to choose a rational failure criterion and strengthen the monitoring and stability control of matric suction. These results obtained in this study could provide theoretical guidance for optimized design and construction for slope support.