Debris Flow Hazard Zoning Based on Numerical Simulation in the Wenchuan Earthquake Meizoseismal Areas

摘要

The Wenchuan earthquake triggered a large number of landslides and collapses in the quake-hit areas, which left a tremendous amount of loose deposits on the slopes and on the valley bottoms. The debris flow pregnant environment has changed dramatically, making the hazard level of debris flow increased greatly. After the earthquake, debris flow hazards occurred frequently and effective hazard assessment of debris flow has become extremely important. The Wu Xianmiao gully in Du Jiangyan city, located in the meizoseismal areas, was selected as the study area. Based on the research of disaster - pregnant environment, a 3-D debris flow numerical simulation platform was established first, then, the hydrological frequency analysis method and the empirical model were used to calculate the debris flow process under the different design frequency (5%, 2% and 1%), the final accumulated scope and depth of debris flow were simulated by the Flow3D software, and the debris flow hazard zonings under the different design frequency were mapped finally.