清江隔河岩库区杨家槽滑坡成因机制及稳定性分析

The Analysis of Formation Mechanism and Stability of Yangjiacao Landslide in Geheyan Reservoir on Qingjiang River

杨家槽滑坡位于清江左岸，距隔河岩水库坝址23km。根据野外调查和工程勘察资料，该滑坡形成于2．2～2．4万年前，由上、下两次级滑坡体组成。上滑体为基岩切层滑坡，下滑体为松散坡积物式滑坡，上、下滑坡体地质特征清晰，主滑带分带性明显。在上、下两滑体之间即上滑体的前缘存在一未滑动体，对上滑体起挡土墙作用。且下滑体下部发育一个规模较大的地下岩溶洞穴，洞穴沉积物齐全、完整，常年流水，成为滑坡体天然的地下水排泄通道，有利于下滑体的长期稳定。对该滑坡进行稳定性分析结果表明，在目前正常蓄水条件下，该滑坡基本处于稳定状态。

Yangjiacao landslide, which lies to the left shore of qingjiang river, is made up of two parts- up- sliding mass and down - sliding mass. It is about 23km from Yangjiacao landslide to the dam of Geheyan Reservoir. According to engineering exploration data and field investigation, the landslide is dated as being of an age of 22000 -24000a, the up- sliding mass is a landslide of cutting bedrock and the down- sliding mass is a landslide of loose slope wash. The geological characteristics of both up - sliding mass and down - sliding mass is very clear and the zonation of main glide zone is very distinct. An unmoving sliding mass, which was found between upsliding mass and down- sliding mass - the front of up - sliding mass, plays a supporting wall in the up - sliding mass. And a large karstic cave was also revealed in the down- sliding mass with an underground river flowing into the Qingjiang river and formed a natural underground drainage. So the existence of large karstic cave is propitious to the landslide stability of down - sliding mass. The result of calculation shows that the landslide is basically steady under the condition of impounding at present.