河北省顺平县李思庄滑坡稳定性分析

Analysis of the stability of the Lisizhuang landslide in Shunping County,Hebei Province

李思庄滑坡为河北省顺平县境内潜在危险性最大的一残坡积堆积层滑坡,近年由于削坡建房,滑坡稳定性降低,极端降雨条件下存在复活可能。在野外调查确定滑坡结构特征的基础上,采用改进Mein-Larson降雨入渗模型分析不同降雨强度及持时对李思庄滑坡安全系数影响,运用有限差分软件FLAC3D计算分析该滑坡在天然和极端降雨工况下的稳定状态。研究结果表明:天然状态下,边坡潜在滑移面为基岩与残坡积层分界面,边坡安全系数为1.18,未发生失稳破坏;随降雨历时增加,潜在滑移面由基岩与残坡积层分界面转移到湿润峰面,当湿润峰达到基岩与残坡积层分界面,边坡安全系数为0.83,属不稳定状态。并对李思庄滑坡初步提出设置挡土墙和截排水沟的治理建议。

The Lisizhuang landslide is the most potentially dangerous accumulation landslide in a residual slope accumulation layer.The toe of the landslide slope was cut to meet the need of construction land,reducing the stability of the landslide.Under the extreme rainfall conditions,the landslide may revive.Based on the field survey,the structural characteristics and main factors affecting the stability of the Lisizhuang landslide are determined.An improved Mein-Larson rainfall infiltration model was utilized to analyze the influence of different rainfall intensities and durations on the safety factor of the landslide.And the finite difference software FLAC3 D was used to simulate the stability of the landslide under natural conditions and extreme rainfall conditions.The results show that:In the natural state,the potential slip surface of the slope is the interface between the bedrock and the residual slope,and the safety factor is 1.18.The landslide stays stable.With the increase of the rainfall duration,the potential slip surface is transferred from the interface between the bedrock and the residual slope to the wetting front.When the wetting front reaches the boundary between the bedrock and the residual slope,the numerical simulation shows that the safety factor of the landslide is 0.83,and the landslide is unstable.Retaining wall and drainage ditch for slope treatments of the Lisizhuang landslide are put forward in this paper.