改进剩余推力法及其在三板溪滑坡稳定研究中的应用

Improved residual thrust method and its application to stabilization study of Sanbanxi Landslide

基于传统剩余推力法和Sarma法,提出改进剩余推力法,以位于三板溪电站进水口上游的滑坡体为例,说明了对水利水电工程诱发的滑坡灾害的评价和治理方法。采用剩余推力法和改进剩余推力法对三板溪滑坡的天然状态、水库蓄水、地震、库水位骤降等工况进行了稳定分析。结果显示,在水库蓄水、地震、库水位骤降工况下,该滑坡的稳定性低于设计标准,因此,须采取相应的加固措施。推荐了抗滑桩设计方案,已经在三板溪滑坡工程中成功实施。

This paper aims to present the authors＇ improved method of the residual thrust based on the conventional residual thrust method and Sarma method by taking the water intake of Sanbanxi hydropower project for an example to show how to evaluate and mitigate the geological catastrophe due to the construction of hydropower stations. The basic idea of improving residual thrust to be suggested is that, when the yield occurs at a sliding surface, Sarma method can be used to predict the action between slices, i.e., the shear force is calculated by the Mohr-Coulomb criterion on the condition that the horizontal thrust is unchanged. Joining the traditional residual thrust method and the improved residual thrust method, we can analyze the stability of Sanbanxi landslide under the natural environment conditions, by taking into full account the reservoir impounding, earthquake, and sudden decrease of the reservoir level, etc. The analysis results show that the stability of the landslide is lower than the design standard under reservoir impounding, earthquake, and sudden decrease of the reservoir level. Therefore it is necessary to take stabilization measures. In addition, since the landslide of Sanbanxi is not too thick, and the bed rock under the sliding is integral and good quality, the pre-stress anchored piles are recommended to improve the stability. According to the residual thrust curves, piles with pre-stressed anchor cable are deployed, which has been implemented successfully.