SLIDING CHARACTERISTICS OF HIGH-SPEED AND LONG RUN-OUT GIANT ROCKSLIDE LANDSLIDE AT WENJIAGOU STREAM

Wenjiagou landslide is a giant rockslide with high-speed and long run-out.It was triggered by the 2008 Wenchuan earthquake.But its sliding characteristic is unclear so far.This paper presents a study on the sliding characteristic of this rockslide.It is based on the field investigation and is combined with remote sensing interpretation.The conclusions are as follows: The slip mass started diversity from source area,scraped rock-soil body of slope surface at the slope area,and then glided or flied into Wenjia gully,continued to downslide along the gully,meanwhile scraped the both valley side slopes.The rock mass occurred five times large-scale collisions with the bank slopes,disintegrated into debris gradually.The debris began to slow down and accumulate in large-scale after the third collision.Finally some sediments reached the valley mouth.The results show that,the hilly terrain is the controlling factor of sliding and accumulation of slip mass,climb,toss,overtopping of slip mass when it crashed into a hill.The disintegration into debris of slip mass and the formation of air blast were the concrete manifestation of high-speed travel.The collision was the main way leading to the disintegration of debris in the whole process.