Distribution Law And Risk Assessment Of Debris Flow In Meigu River Basin Southwest Of Sichuan

Debris flow is one of the most serious geological disasters in China,which is sudden and destructive.Because of the influence of neotectonic movement,the complex terrain and the geological conditions,earthquake action,and the rock fragmentation,which make debris flow occurring frequently in this area.This paper studies the Meigu River Basin,which is located in Liangshan Yi Autonomous Prefecture of Sichuan Province.The Meigu River Basin Locate in the deep valley,the two sides of the valley by the impact of the fracture.The whole mountain ranges from NW to SE,and the natural disasters occur frequently in the area,especially the debris flow disaster,which poses a great threat to the safety of the local residents.Paper combine with the project of geological disasters in the Meigu River Basin,mainly study of the Meigu River Basin spatial distribution characteristics of debris flow,debris flow disaster background.formation mechanism,the debris flow accumulation area risk range and other aspects.Combined with numerical simulation software CFX to simulate the velocity field of Yuewule debris flow.To get the Yuewule debris flow danger area and velocity field distribution.This paper mainly studies the following aspects.(1)Making statistics 90 debris flow gully in the Meigu River Basin based on a large number of field investigation and remote sensing interpretation.Different types of debris flow are classified from different angles,which according to the terrains and landscapes,the cause of formation and the rainfall in the basin.(2)Combined with the distribution of rainfall in the watershed and the distribution of faults in the watershed to analyse the spatial distribution characteristics of debris flow in Meigu River Basin.And getting the reason of the distribution of debris flow in the watershed.(3)According determination of the influencing factors of the accumulation form of accumulation fan two factors were selected,which is including the height difference and the source quantity in final.Based on a summary of the previous range of debris flow risk function model to get the function model of Meigu River basin within the scope of the debris flow risk from improving the function in final.To establish the function model of Meigu River basin within the scope of the debris flow risk.(4)Based on field investigation,firstly using rain flood method to calculate the flow of Yuewule debris flow in study area.secondly using RHINO software to build 3D terrain model of Yuewule debris flow.Combining with numerical simulation software CFX to simulate the Yuewule debris flow.According the calculated flow value of debris flow to simulate the whole basin of Yuewule debris flow.To analyse occurrence,movement and accumulation of the debris flow under the condition of outbreak frequency in 2%(the heavy rain once in 50 years).In final to get the velocity field cloud chart of Yuewule debris flow.It can clearly get the accumulation form of debris flow fan to verify the function model of the debris flow dangerous range.