SURGE GENERATION IN RESERVOIRS BY LANDSLIDES TRIGGERED BY THE WENCHUAN EARTHQUAKE

Landslides can result in rocks and soil falling into reservoir at high velocity, thereby triggering large surface waves, which may threaten navigation vessels, dam stability, and lives and properties along the shore. This paper presents the results of an experimental study into surges caused by landslides entering reservoirs. First, eight factors water depth, sliding impact velocity, slide volume, slide width, slide thickness, the mass of the slide blocks, sliding slope, and drop height of the mass center - were chosen as key parameters. Then, these were combined into four dimensionless factors: Froude number for sliding velocity, landslide scale, slide thickness and slide impact angle (radian measure). In addition, based on data from 145 model tests, empirical equations for prediction of the first and second impulsive wave heights were developed through nondimensional multiple linear regression analysis. These equations were applied to landslides triggered by the Wenchuan Earthquake along the shore of Zipingpu Reservoir. The calculated results were found to be in good agreement with field surveys and with calculations by other formulas; the proposed formula is believed preferable in that it incorporates dimension parameters and slope of the sliding surface.