Geological Disasters In Liulin County Based On AHP- Information Method Risk Assessment And Risk Control Research

In this paper,for the first time,geological hazards in Liulin County are systematically evaluated in terms of susceptibility,hazard,vulnerability and risk.Based on the spatial analysis capability of the GIS system,combined with the AHP-information model,the study of geological hazard risk evaluation in Liulin County was carried out,the methodological system of geological hazard risk evaluation in Liulin County was established,and according to the distribution characteristics of riskiness,the risk zoning and preven.tion zoning of geological hazards were divided,the risk control measures for different prevention and control levels of geological hazards in Liulin County were proposed,and the geological hazard risk control system was established.The main results were achieved as follows:(1)The types,characteristics and distribution patterns of geological hazards developed in Liulin County were identified.The research results show that there are 270 geological hazards in Liulin County,including 91 landslides(33.70%),162 landslides(60%),2 mudslides(0.74%)and 15 ground collapses(5.56%),mainly landslides and landslides,and their scale is mainly small.Spatially,geological hazards in Liulin County are mainly distributed in places with strong human activities and poor geological conditions,and temporally,they are mainly concentrated in the rainy season and the period of strong human activities.(2)The formation conditions and mechanisms of geological hazards in Liulin County were revealed.The results of the study show that geological hazards in Liulin County are influenced by topography,geotechnical type,slope structure,rainfall,water system,human engineering activities and vegetation.The formation mechanism of landslides and collapses is analysed,with landslide hazard formation mechanism being analysed as landslides within the loess layer and landslides on the contact surface of the loess bedrock,and collapses can be classified into three types according to the mechanism: tipping,sliding and falling.(3)The evaluation indexes of slope,slope height,slope direction,slope type,landform,engineering geological rock group,distance from water system,distance from road,distance from residential land,distance from mine and vegetation cover were selected,and the AHP-information method was used to evaluate the geological disaster susceptibility of Liulin County.The evaluation results are: very high susceptibility zone covers 243.93 km~2,accounting for 18.95% of the county area;high susceptibility zone covers 428.44 km~2,accounting for 33.28% of the county area;medium susceptibility zone covers 270.51 km~2,accounting for 21.01% of the county area;low susceptibility zone covers 344.63 km~2,accounting for 26.77% of the county area.(4)The results of the vulnerability evaluation and rainfall were used as evaluation indicators to carry out the geological hazard evaluation of Liulin County,the results of which were: very high hazard area of 166.08 km~2,accounting for 12.90%;high hazard area of 400.98 km~2,accounting for 31.14%;medium hazard area of 424.93 km~2,accounting for 33%;and low hazard area of 295.52 km~2,accounting for accounting for 22.95% of the county.(5)The vulnerability of people,the vulnerability of buildings and the vulnerability of roads were selected as vulnerability evaluation indicators,and based on the results of hazard evaluation and vulnerability evaluation,the geological hazard risk evaluation of Liulin County was carried out: The very high risk area is 82.77km~2,accounting for 6.43% of the total area,with 100 geological hazards;the high risk area is 205.56 km~2,accounting for 15.97% of the total area,with 87 geological hazards;the medium risk area is 710.86 km~2,accounting for 55.21% of the total area,with 80 geological hazards;and the low risk area is 288.31 km~2,accounting for 22.39% of the total area,with 3 geological hazards.(6)Based on the qualitative evaluation of the risk of single geological hazards in Liulin County,the landslide in Wangjiagou Village was selected for quantitative risk evaluation,the results of which were: under natural working conditions,the risk of people reached 0.1759 and the risk of property reached 275.108 million yuan;under full water working conditions,the risk of people reached 0.8839 and the risk of property reached 1.3821.67 million yuan.(7)On the basis of the geological disaster risk evaluation,the geological disaster risk control measures in Liulin County were carried out.The results of the study show that: the distribution of key prevention and control areas covers an area of 397.07km~2,accounting for 30.84%;the secondary key prevention and control areas cover an area of 544.66 km~2,accounting for 42.30%;the general prevention and control areas cover an area of 345.77 km~2,accounting for 26.86%,and for the general prevention and control areas risk control is recommended to be based on group survey and prevention,while the secondary key prevention and control areas are based on group survey and prevention supplemented by engineering treatment.The key control areas need to carry out group survey and prevention work on a regular basis,and choose relocation and avoidance,risk removal and engineering management measures according to the risk situation and scale.According to the different areas,corresponding risk control measures are proposed.