Occurrence conditions and process analysis on fluidization of valley type landslide: Example of the fluidization of landslide in Qiongshan Ravine, Danba

A big debris flow which was arosed by landslide occurrence at night on July 11, 2003 in Qiongshan Ravine, Danba, Sichuan Province. According to the research, debris flow in Qiongshan Ravine is arosed by the fluidization of landslide. It had been rained about 70 days before debris flow occurred. That made the sediments in the gully to near to saturated or saturated in water. Being affect by the steep geography, the sediments occurrence peristalsis to transform, parts of soil bodies start disintegrate. All the sediments become transforming with water inleakaging to sediments, and than foreside slope flow to gully quickly after becoming fluidization. And the sediments come into being the debris flow with the water of the gully joining.