Research On Risk Comprehensive Evaluation Of Typical Geological Disasters In Xishan Mining Area Of Beijing Region

Xishan mining region of Beijing is located in Western Hills of Beijing,the landform belongs to middle-low mountain,the slope is steep and the ditch is depth,geological disasters are distributed wider, it is the most serious geological disasters region in Beijing. After many years of coal mining, land collapse and related geological disasters becoming more and more serious, hinder local economic development, pose a significant threat to the local people's lives and property. So there is a need for the risk evaluation of geological disasters and to provide a scientific basis for development plan and to prevent geological disasters in Xishan mining region of Beijing.Based on the thesis research and field survey, and according geological environment background conditions of the mining area, identified the types of geological disasters and its influencing factors, Discuss the characteristics of geological disasters and its distribution application in time and space, study the formation mechanism of land collapse and debris flow, and evaluated the risk of typical geological disaster based base on GIS technology, to have the following main results:1.The types of geological disasters in mining areas includes land collapse, debris flows, landslides, avalanches.Land collapse and debris flows are in the main.2.The land collapse is caused by coal mining, its main performance are collapse pits, uneven surface subsidence and the cracking in the top of the mountain caused by the goaf of the lower part , subsidence basin is only developed in a few areas. The coal mining is not only for the formation of mine goaf, also caused the formation of a large number of abandoned waste rock pile, to provide adequate source for the occurrence of debris flow.3.Most of the ancient debris flow channels of the region is in stage of decline to death, has been for a considerable protective measures, and because of little rain all the year round, has less dangerous.However, there is a rich source of material in the source of the secondary tributaries of main debris flow gully, it still has the danger of debris flow when heavy rainfall happened.4.Use the bipolar fuzzy comprehensive evaluation method and overlay method to risk analysis on two typical geological disasters in mining areas - land collapse and debris flow.Combined with distribution law, the causes, mechanism and status quo of geological disasters, set up a geological hazard evaluation factors system and grading standards for evaluation factors, use AHP to determine weights of evaluation factors, and use overlay method to carry out a comprehensive analysis of the two types disasters. 5.Set up spatial and property database of the geological disasters, use GIS spatialanalysis function, divided into three levels of the geological disasters danger in the region:risk,relatively risk and stable area.The comprehensive evaluation results show that the risk level has significantly zoned features.The risk area distribution of land collapse is consistent with the mined-out area.