Evaluation Of Debris Flow Vulnerability On Both Sides Of Taohe Daban-Tangwang Section Based On GIS And AHP

Based on the investigation project of geological hazards in the lower reaches of the Taohe River basin undertaken by the Ministry of Land and Resources of the Geological Environment Monitoring Institute of China,through the field investigation and data integration of the participating projects(Tangwangchuan),the influence factors of debris flow geological hazards in the study area are analyzed by AHP,and the contribution degree of the selected main control factors is determined.Based on the qualitative and quantitative evaluation of GIS technology,the susceptibility of debris flow geological hazards in the downstream study area of Taohe was evaluated,and the degree of susceptibility of 30 debris flow trenches in the study area was quantitatively evaluated by grey extension model.The conclusions are as follows:(1)The loess in the lower reaches of Taohe basin is widely exposed,the structure of rock and soil is loose,the human engineering activities are strong,the geological structure,mountain height difference,topography and geomorphology,mountain slope,geotechnical structure type,vegetation development,seismic intensity,rainfall,human engineering activities and so on are the main causes of debris flow disaster in Among them,rainfall and human activities are the two most important predisposing factors,the analytic hierarchy process shows that the weight of this factor induced debris flow is0.0606,0.0101,0.0303,0.0506,0.0303,0.0758,0.0909,0.2727 and 0.3787.(2)The vulnerability of debris flow is divided into highly prone,high-prone,prone,moderate and easy to send,five levels,with the help of GIS spatial difference analysis from the plane to the study area of debris flow prone quantitative evaluation.The total area of the evaluation area is 431.42km~2,in which the area of the highly prone area is5.37km~2,accounting for 1.24%,the area of the high-prone area is 107.25km~2,the proportion is 24.86%,the area of the prone area is 80.93km~2,the proportion is 18.76%,and the area of the medium prone area is 98.06km~2,22.73%;The area of 139.81km~2 is not easy to send,and the proportion is 32.41%.(3)For Geological Survey,data collection and in-depth study of Branch groove in the lower reaches of the Taohe basin,a total of 30 important Branch groove with potential hazards of debris flow were found in the study area.By screening,seven indexes,such as the size ratio of source recharge,vegetation cover,mountain slope,debris flow basin area,relative height difference,longitudinal drop ratio of debris flow main ditch and 24h maximum rainfall,were selected as evaluation factors,and the debris flow susceptibility of each yinjiao was evaluated quantitatively.Of these 30debris flow valleys,7 are highly prone debris flow trenches,accounting for 23.3%;9 are high-prone debris flow trenches,the proportion is 30%;2 are prone debris flow trenches,the proportion is 6.7%;6 are prone debris flow trenches,accounting for 20%;6 are not easy to send debris flow ditch,accounting for 20%.