基于滑带土等效抗剪强度参数的古滑坡稳定性分析

采用野外直剪试验方法测定鹅公带古滑坡体滑带土强度参数，据此求得的滑坡稳定安全系数与古滑坡已处于临界失稳的现状不符，为此特提出考虑降雨条件下浸润线升高等因素影响下的滑带土等效抗剪强度参数，利用强度折减法，通过FLAC3D软件反分析得到等效抗剪强度参数，并利用该参数计算不同运行工况下的鹅公带古滑坡体稳定安全系数。结果表明，各种工况下古滑坡稳定安全系数均不满足规范要求，且在汛限水位及水位骤降情况下处于失稳状态，应进行加固处理。

Stability Analysis of Ancient Landslide Based on Equivalent Shear Strength Parameters of Slip Soil

Field direct shear test method is adopted to measure the strength parameters of the slip soil of Egongdai ancient landslide. And then the stability safety factor is calculated. However, it is not consistent with the critical instability situation of the ancient landslide. To solve this problem, the equivalent shear strength parameter of the slip soil is proposed, which considered the impact of exaltation of the saturation lines under rainfall conditions. Based on the test results of strength parameters of the slip soil and the strength reduction method, the equivalent shear strength parameter is obtained through back analysis by using FLAC3D. Finally, the stability safety factors of Egongdai ancient landslide are calculated with the equivalent shear strength parameter under different operating conditions. The results show that the stability safety factors of Egongdai ancient landslide under different operating conditions are not satisfied with specification requirements and the landslide is in the unstable state under conditions of flood control level and rapid drawdown, which illustrates that the landslide should be treated by consolidation.