宁夏贺兰山贺兰沟"8·21"泥石流运动分析与易发性评价OA

On August 21,2016,a debris flow disaster occurred in Helan Valley,Helan Mountain,Ningxia.Therefore,based on DEM elevation and high-precision images,an ArcGis computational model was established to obtain parameters such as bulk density,flow velocity,flow rate,and total volume of the debris flow process in Helan Valley.The Massflow software was used to simulate the movement characteristics of the debris flow in Helan Valley and analyze the variations in sediment depth and flow velocity.By combining the topography,material sources,and water sources,the susceptibility characteristics of the debris flow were evaluated.The results showed that the 8·21 debris flow in Helan Valley was a rare debris flow triggered by short-duration heavy rainfall,with flow velocities primarily below 6 m/s.The sparse vegetation in Helan Valley resulted in minimal resistance,leading to higher flow velocities;the average sediment depth ranged from 1 to 6 m,with a maximum sediment depth exceeding 10 m.The sediment depth was greatest in the middle of the valley and gradually decreased along the sides of the valley;the total volume of a single debris flow event was 4.81×105 m3,indicating a moderate susceptibility to debris flows.