Research On Risk Assessment Of Debris Flow Based On Numerical Simulation And Fuzzy Analytic Hierarchy Process

In recent years,frequent debris flow in China have caused great threats to the lives and property safety of local people.Mountain ranges are widely distributed in the west and northeast of Beijing,while the central and southern parts of the country are plains.Under the influence of the monsoon,it is easy to form a large heavy rains have led to frequent mountain torrents and debris flow in Beijing.Therefore,it is necessary to investigate Beijing's debris flow and take corresponding control measures.Based on the DEM in the study area,the information of the Hongshuiyu debris flow in the Mentougou area was extracted,and the basic characteristics of the debris flow were determined.The LAHARZ software was used to simulate debris flow.The fuzzy analytic hierarchy process was used to calculate the risk of debris flow.Based on the GIS platform,three evaluation factors were selected to classify the debris flow.The following results were obtained:1.The debris flow belongs to the gully-type debris flow with heavy rain and the source is waste.The activity intensity is strong,the disaster-causing ability is strong,and it is easy to develop.There are several concrete masonry retaining dams in the main ditch,and there is a slight damage to the retaining dam at the downstream,which are hidden dangers.There are more coal gangue deposits and loose gravel generated by artificial excavation in the ditch,which provides sufficient source for the debris flow and threatens the residential area of the stacked fan.2.According to the LAHARZ mathematical model,the debris flow data of some parts of China were introduced,and the parameters of the original mathematical model were modified to obtain the modified model,A=0.205V^0.5866,B=3.991V^0.8790,and the modified model was used to carry out the debris flow.The numerical simulation of the accumulation range has obtained the debris flow accumulation range map.The results show that the debris accumulation in the50-year and 100-year storm conditions has flooded the village.Residents in the accumulation area during the rainstorm are more likely to be affected by the disaster.3.According to the characteristics of debris flow in the study area,eight risk assessment factors were selected.The fuzzy analytic hierarchy process was used to evaluate the risk of debris flow in the study area.The evaluation results were highly dangerous.4.According to the distance from the main ditch,the terrain slope and the simulated accumulation range,the AHP method is used to determine the weight of each factor.Based on the GIS platform,the risk zoning map of debris flow is obtained.The results show the midstream and downstream accumulation.The level of danger is higher within 20m on both sides of the main ditch.