Abstract:

The Qianjiangping landslide, located in China’s Three Gorges Reservoir（TGR）, occurred on 13th July 2003 , one month after the first impoundment to 135 m a.s.l. of TGR water level. This is the first reservoir triggered landslide in TGR. This huge landslide was a high speed dip rockslide with a volume of 15 million m3, a maximum sliding velocity of 16m/s. The maximum surge height was 24.5 m, and the sliding process was finished in less then 1 minute. The catastrophic landslide caused 10 people died, 14 people disappeared, destroyed 129 houses and 4 factories, and left 1 200 people homeless. After the landslide, the author continued research on the high speed slide mechanism in order to predict the same kind of landslide disaster in the TGR area and elsewhere in the world. On the research effort on the high speed slide mechanism seen in the Qianjiangping landslide based on geologic analysis and numerical computations, it is concluded that the Qianjiangping landslide had a typical geological structure needed to gestate a high speed landslide; the great decline in shear strength in the shear zone (from peak to residual) is the essential cause for the high initial sliding speed; and the potential energy of the high slope and the liquefaction of the shear zone accelerated the sliding.

Key words: Qianjiangping landslide, high speed slide, slide zone, shear strength, great decline in shear strength from peak to residual