A Study On The Degree And Risk Assessment Of Debris Flow At Wa Fangdonggou County In Chengde City

The debris flow of Wafangdonggou in Chengde City endangered the safety of the lives and property of 30 villagers in 30 households in the lower reaches of the channel and in Mizoguchi and directly threatened about 13.1 million yuan of property.Therefore,it is necessary to carry out the vulnerability assessment and hazard analysis of the debris flow geological disasters in Wafangdongou.The paper takes the debris flow of Wafangdonggou in Guojiatun Town,Chengde City as the research object.Firstly,the natural geographical conditions,channel conditions,the distribution and characteristics of provenance conditions are analyzed and collatinged.Secondly,based on the above conditions,The basic movement characteristic value of debris flow was calculated.Finally,two methods were respectively used to analyze the degree of debris flow hazard and debris flow hazard,and the prediction diagram of the maximum risk range of debris flow was drawn.Evaluation of susceptible degree:The application of fuzzy comprehensive evaluation(indirect evaluation method)and“debris flow disaster prevention and control engineering exploration specification”(direct evaluation method)were respectively analyzed for vulnerability of debris flow;fuzzy comprehensive evaluation method first selected the appropriate evaluation Factor,the AHP is used to analyze the weight of each influencing factor,and finally the fuzzy matrix is established.Finally,the vulnerability of debris flow is easy to be found.Using the relevant methods in the “Specifications for the Exploration of Debris Flow Prevention and Control Project”(Direct Evaluation Method)The conclusion is mild.According to the direct evaluation method,the basic data needed for evaluating the vulnerability degree of single gully debris flow is relatively complete.The indirect index evaluation method is based on the modeling of the terrain environment,rainfall and vegetation cover in the area where debris flow ditches are located,and the data is relatively easy to evaluate obtain.Risk Assessment: By applying the general evaluation model and the risk assessment model of debris flow in the single gully of Liu Xilin,the risk of debris flow in Wafangdonggou was evaluated respectively.The conclusions of the risk of debris flow in Wafangdonggou obtained by the two evaluation models are somewhat different.The former is a moderately dangerous conclusion,while the latter is a low-risk conclusion.The reason for the difference is that Liu Xilin’s model focuses on the basic characteristics of debris flow itself,while the general evaluation model not only considers the characteristics of debris flow movement,but also considers the characteristics of debris flow itself and the probability of occurrence,accounting for a relatively comprehensive consideration.Taking into account the safety of downstream residents and the reliability of data,the paper draws conclusions from the first method as the main reference,that is,the debris flow ditch is moderately dangerous.The research results can provide a scientific basis for the sustainable economic development and transportation planning and disaster reduction planning in this area.The study combined with the actual engineering analysis and research,with strong practical value,will also provide similar reference for the future risk assessment of debris flow ditch.