Research On Debris Flow Risk Assessment Method System Based On The West Hill In Beijing

Debris flow is a sudden geological disaster in mountainous areas and is highly destructive.Debris flow disasters are the most serious and harmful types of geological disasters in Beijing's mountainous areas.Improving the research level of debris flow risk assessment in Beijing mountainous areas,and supporting disaster prevention and mitigation work is an urgent task.Many scholars have carried out related explorations on the risk assessment of debris flow in Beijing mountainous areas.In the process of research,there are still many difficulties in the selection of debris flow risk assessment indicators,index standardization,and index empowerment.This paper takes Beijing western hill area as the research area,and takes 197 debris flow hidden ditch in the study area as the research object.On the basis of fully reading the data collected from the study area,using remote sensing,GIS technology,combined with field investigation,using qualitative description,normal Distribution method,natural breakpoint method,analytic hierarchy process,coefficient of variation method,combined weighting method,etc.,to select the indicators of debris flow risk assessment,extract information,complete the standardization and empowerment,and finally constructed the risk of debris flow evaluation system on The West Hill in Beijing and completed the quantitative risk assessment,sorting and grading of the debris flow hazard in the study area.This paper has mainly achieved the following research results:(1)By referring to relevant literature and norms,the characteristics of debris flow ditch in the study area are fully analyzed,and 17 debris flow hazards suitable for the study area are selected from four aspects: source conditions,dynamic comprehensive conditions,geological conditions and rainfall conditions.The information extraction of the 197 debris flow hazard indicators was carried out,and a good information extraction effect was obtained.(2)Based on the results of the index extraction of the debris flow ditch,based on the characteristics of the indicator and the statistical rules of the histogram of the index,qualitative description,normal distribution and natural breakpoint are used respectively.The evaluation indicators are standardized,and the indicators are divided into three levels: severe,medium and slight.The standardized results of the indicators are objective and reliable.(3)Using the coefficient of variation method to apply the statistical results of the indicators of the hidden debris flow in the study area to the indicator weighting.The combination weighting method is used to combine the weights of the indicators obtained by the subjective weighting method(AHP)and the objective weighting method(the coefficient of variation method)to obtain the optimal index weight value.(4)Adding data of 17 indicators of 197 debris flow hazards in the study area to the risk assessment system,and establishing a debris flow risk assessment system on the west hill in Beijing.The quantitative risk assessment,ranking and grading of the debris flow ditch in the study area were completed.The evaluation results show that there is a large regional difference in the risk of debris flow in the study area;the risk of debris flow hazard is generally high;the risk evaluation score is higher.The gully is subject to a mudslide disaster,and there is a high possibility of a mudslide disaster.