| With the continuous acceleration of the urbanization process,the geological safety problems faced by the city are further highlighted.And the risk assessment and early warning control methods of urban geological safety need to be established urgently.Based on the project of"Research on the Construction Method of Yunnan Urban Geological Information Platform",this paper comprehensively considers the geological environment,factors and various indexes under historical disaster conditions of disaster-causing bodies in cities as evaluation factors for the evaluation method of urban geological safety,and establishes and integrates a set of comprehensive and systematic index system suitable for urban geological safety risk evaluation in intermountain basins.The index system includes six sub-evaluation systems:landslide,collapse,debris flow,land subsidence,karst collapse and sand liquefaction.On the basis of referring to relevant industry norms,standards and monographs,the risk classification and standardization of each evaluation factor were carried out.At the same time,the weight of each evaluation factor was obtained by yaahp software using analytic hierarchy process combined with expert scoring,which ensured the integrity of the index system.At the same time,taking the built urban area of Baoshan Basin in Yunnan Province as an example,through drilling data and other geological data,the soil distribution of land subsidence,potential karst collapse and sand liquefaction is revealed by EVS three-dimensional visual transparent model.And the risk zoning evaluation of these three types of disaster-causing bodies is carried out by using the relevant modules of Arcgis software.It is concluded that the areas with high risk,relatively high risk,medium risk and low risk of land subsidence in the study area are about 0.07545 km~2,21.3982 km~2,20.5635 km~2 and 0.8082 km~2,respectively,and the area proportions are about 0.1761%,49.9429%,47.9947%and 1.8863%,respectively.In the study area,there are soluble salt rock hidden danger strata that lead to potential karst collapse.There are only medium and small risk zones in the hidden danger stratum area,with an area of 3.73 km~2 and 0.93 km~2 respectively,accounting for 80.04%and 19.6%of the total area of potential karst collapse area.There are only zones with relatively high,medium and low risk of sand liquefaction in the study area,with an area of 0.94408km~2,1.65074 km~2 and 40.25052 km~2,respectively,accounting for 2.7675%,4.8390%and 92.3935%of the total area of the study area.The results obtained are consistent with the current understanding,which shows the rationality and scientificity of the index system and evaluation method.Finally,on the basis of the evaluation results,with reference to the relevant standards,the index factors that affect and control the occurrence of disaster-causing bodies are taken as the entry point,and the monitoring and early warning research is carried out on the key hidden danger areas.According to the characteristics and risk degree of the disaster-causing body,the comprehensive control measures of’avoidance measures,engineering protection,monitoring measures and establishment of group prevention system’are put forward,which provides a scientific and reliable reference for the prevention and control of geological disasters in the study area. |
