Risk Assessment And Numerical Simulation Study Of Buzha Debris Flow In Xiongru Township, Saga County

The “4.25” Nepal earthquake triggered a large number of unfavorable geological phenomena such as collapse and landslide,which increased the amount of loose solid matter in the channel and provided a rich source of material for the formation of debris flow.Under heavy rainfall conditions,the debris flow is easily stimulated after the earthquake,posing a serious threat to the life and property safety of the Mizoguchi residents.Therefore,the study of debris flow disasters after the earthquake has great practical significance.This thesis takes the Buzha mudslide in Xiongru Township,Saga County,Tibet as the research object.Starting from the regional geological environment background of the study area,the formation conditions of the Buzha debris flow were analyzed.On this basis,the fuzzy comprehensive evaluation method is used to evaluate the risk of the Buzha debris flow.At the same time,the CFX software is used to simulate the fluid movement in the debris flow gully accumulation area.The results of risk assessment and numerical simulation have guiding significance and reference value for the treatment,prevention and post-disaster recovery of debris flow.The main findings of this paper are as follows:(1)Based on the field investigation of the study area,the background of the geological environment of the study area is analyzed,and the formation conditions of the debris flow are studied from three aspects: topographic and geomorphic conditions,provenance conditions and water source conditions.In addition,according to the relevant specifications and formulas,the debris flow dynamics parameters are calculated,which provides basic data for debris flow hazard evaluation and numerical simulation.(2)According to the actual situation of the debris flow in the study area,nine factors affecting the risk of debris flow were selected as the evaluation indicators,and the weights of each evaluation factor were determined by the analytic hierarchy process.The risk is mainly affected by its own characteristics and hydrometeorological conditions,and human engineering activities have the least impact.The fuzzy comprehensive evaluation method is used to evaluate the risk of the debris flow.The evaluation results show that the dangerous level is highly dangerous.It is recommended to carry out key monitoring and prevention of the debris flow.(3)Establish a 3D geological model of the Buzha debris flow,The CFX software is used to simulate the motion process of the debris flow gully accumulation area.The flooding process of debris flow in the ditch accumulation area is analyzed.The simulation results are close to the actual situation and the accuracy is high.