重力坝双滑面抗滑稳定分析中抗力角的取值建议

Suggestion on resisting force angle specified in the gravity dam design code for wedge stability analysis

重力坝设计规范中分析坝基抗滑稳定的等K法只考虑了力的平衡,而没有考虑由双斜面构成的滑体是否为运动许可。本文基于边坡稳定性分析中Sarma法的基本假设,建议将极限状态下两块体交界面设为破裂面并与上下游滑面具有相同的强度储备,从而形成运动许可机构;在原来算法上做较小的改动,即可同时得到抗力的大小、方向以及安全系数,为重力坝设计中对抗力角取值提供了依据。

In the design code of gravity dams,the method of equal safety factor for evaluating the stability of a gravity dam against deep slide in its foundation,considers only the equilibrium of forces,while ignoring the kinematical admissibility.Based on Sarma＇s assumption for satisfying the kinematical admissibility,we suggest that the interface between two blocks should be treated as a fracture plane and calculated with the same safety factor as those for the upstream and downstream sliding surfaces.Little modification of the existing algorithm is needed,but the factor of safety and the magnitude and direction of resisting force can be obtained.The importance of this new consideration in the design of gravity dams is emphasized in this paper.