Study On Risk Assessment And Control Countermeasures Of Dahugou Debris Flow In Simenzi Village,Fengcheng City

The debris flow of Simenzi Village,Simenzi Township,Fengcheng City is located in Dahugou,Simenzi Village,Simenzi Township,Fengcheng City,Liaoning Province.The main channel of Dahugou is long and narrow,and the valley is relatively straight and has a length of 3.84km.The slopes on both banks of the valley are relatively unstable,and the heavy rain in the area is concentrated,which provides the excitation conditions for the start of the debris flow.In 1998,dbris flow were outbreakwith heavy rainfall in the area,causing four deaths and serious economic losses.It is necessary to evaluate and control the risk of the debris flow gully.Based on the detailed geological disaster field investigation,the geological environment characteristics of the debris flow channel were identified,and the formation conditions and influencing factors of the debris flow were analyzed.Seven evaluation factors were selected and use the analytic hierarchy process to weight the seven evaluation factors,and finally evaluates the hazard level of the debris flow through the fuzzy comprehensive evaluation method.The treatment measures for the debris flow in theDahugou were proposed.The main research results of the thesis are as follows:(1)Through the field investigation work,the data were analyzed,the geological environment characteristics of the debris flow channel were identified,the formation conditions and influencing factors of the debris flow were analyzed,and the basic characteristic data of the debris flow channel was obtained.The length of the main channel is3.84km,the catchment area is 8.2km~2,the thickness of loose deposits in the main channel is0.8-2.5m,the total amount of unstable square is 82193m~3,the longitudinal slope of the main channel of the valley is 80‰~20‰,and the slope is 30°~70°.The relative relief is 470.99m.(2)Combining the characteristics of the debris flow in this area,select the maximum amount of debris flow,the area of the basin,the cutting density of the basin,the length of the main channel,the maximum relative relief of the basin,the maximum rainfall of 24 hours,and the bending coefficient of the channel.The evaluation factor performs a weight analysis calculation to obtain its weight vector.(3)The one-level fuzzy evaluation method and the two-level fuzzy evaluation method are used to evaluate the risk of the debris flow.The evaluation result of the one-level fuzzy evaluation is 0.6912,and the evaluation result of the two-level fuzzy evaluation is 0.8284.The conclusion is drawn from the conclusion that the dangerous level of the Dahugou Debris flow is grade II and mildly dangerous.At the same time,combined with the actual situation of the outbreaks and casualties caused by the debris flow in the Simenzi in 1998,according to the field survey results,There is a large amount of loose deposit accumulated in the startposition of the channel and the startposition of the branchchannel,so it is necessary to take corresponding measures.(4)Proposed practical engineering measures.1)Clean up the main channel and the branch channel,adopt natural grading and dry masonry to protect the shore,2)build masonry revetment in the upper reaches of Xitou Village and Hugoumen River,3)increase the sandstone of the entrance of Xitou Village to Xitou Village Road and repair the road from Xitou Village to the upper reaches of Dahugou.