降雨和地震耦合作用对滑坡稳定性的影响——以甘肃西和Ⅲ号滑坡为例

以甘肃省西和县西山Ⅲ号滑坡为例分析了地震与降雨耦合作用对滑坡稳定性的影响。采用GEOSTUDIO软件对其进行了天然及地震降雨耦合作用两种条件下的数值模拟。通过计算结果对比可知,西山Ⅲ号滑坡在天然状态下处于稳定状态;地震降雨耦合作用对西山Ⅲ号滑坡的稳定会起到很强的削弱作用,滑坡将处于失稳状态。在此处采用的计算条件下,相同降雨量下地震与不同降雨强度的耦合作用显示,降雨强度越小雨水入渗相对越多,地震作用下超孔隙水压力影响区域越大,滑坡越不稳定。

Stability Analysis of Landslide under Coupling Action of Earthquake and Rainfall—Taking the No.Ⅲ Landslide of Xihe County,Gansu Province as An Example

The stability of landslides under the coupling action of earthquake and rainfall is analyzed with an example of No.Ⅲ landslide of Xihe county,Gansu province.We adopte Geostudio software to simulate the landslide in two conditions,i.e.natural status and the coupling influence from earthquake and rainfall.The analysis result shows that the landslide is generally stable in nature state;on the contrary,the coupling action could have serious impact on the stability of NO.Ⅲ landslide of Xihe county.The result also shows that with same calculation condition and rainfall,a certain magnitude earthquake coupling with three kinds of rainfall intensities could cause different landslide possibilities;the less rainfall intensity may cause the more reduction of the landslide stability,due to a more volume of infiltration water and a wider distributional zone of exceeding pore pressure associated with earthquake.