A STUSY ON THE MECHANISM OF SANDAOGOU LANDSLIDE IN URBAN AREA OF BADONG COUNTY

Sandaogou Landslide is the on-bank (front) part of a large ancient landslide located in the new urban aera of Badong County. First cracks appeared in June, 1995, and progressively developed for 4 months. Then the ground failed and the lanslide took place on 29th of Oct. With a volume of 200, 000 m3. Thanks to correct prediction and in time mitigation measures taken by the local government, the damages caused by this slide were reduced to minimum.The principal factors for the ground deformation and slide are the steep relief on the front of the ancient landslide, very loose landslide deposits with low strength,and river erosion of the southern bank associated with narrowing of the river channel caused by accumulation of fluvial sediments on the opposite bank at Zhajiaoji on the Yangtze River. The triggering factors are rainfall, fluctuating water level, artificial waste loads on the slope from new urban area, dynamic loads, and changing hydrogeological conditions, which resulted in further lowering of mechanical strength of the ground mass and hence led the slope being in a critical state to fail.