Research On Ground Collapse And Prevention Caused By Mining Of A Limestone Mine In Hunan Province

The mining area is located in the northwest of Xiangtan City,with an annual output of 500,000 tons.In recent years,with the deepening of mining and long-term drainage,the groundwater level difference and hydrodynamic conditions have changed.At the same time,due to engineering activities such as blasting during mining,the surface has subsided,deformed and even collapsed.Production and life and the safe production of mining areas pose a threat.Based on the data collection,on-site investigation and geophysical exploration,combined with the characteristics of topography,stratum lithology,geological structure and hydrogeology,this paper summarizes and analyzes the development characteristics and distribution of karst collapse in this area,and studies the impact.The factors of karst collapse in the mining area,especially the hydrogeological characteristics,and the karst development characteristics,distribution rules and evolution mechanism in the area,evaluate the risk of karst ground subsidence in the mining area,and reasonable governance suggestions were put forward for the impact of safe production in the mining area and people’s production and life.The main research results of the thesis are as follows :(1)Basic geological features of the mining area.Based on the comprehensive study of regional geological data,combined with field investigation and exploration,it was found that the main exposed strata in the mining area were the Carboniferous Maping Formation(CPm),the Permian Qixia Formation(Pq)and the Quaternary Baishui River Formation(Qbs).The strata in the mining area are strongly weathered and the cover layer is thick.The tectonic direction is dominated by the northeast-southwest direction,and the small dorsal oblique folds are juxtaposed.The types of groundwater are loose rock pore water,layered rock fissure pore water and carbonate rock fissure cave water.The drainage and recharge are affected by the local climate and the drainage and drainage of the mining area.(2)Characteristics,distribution law and development degree of ground subsidence in mining area.Based on the topography,stratigraphic lithology,geological structure,hydrogeology and engineering geology of the mining area,the detailed investigation and research on the ground collapse caused by mining in the mining area is carried out,and the characteristics,distribution and development degree of the ground collapse are analyzed.(3)Comprehensive Analysis Modeling to Analyze the Causes and Formation Mechanism of Ground Collapse.Through the comprehensive analysis and research on geological data,geological survey,geophysical exploration and mining data,the causes of ground karst collapse in this area are analyzed and studied.The FLAC3 D numerical simulation software is used to evolve the drainage groundwater and karst ground collapse process,and the pumping and drainage pair is analyzed in depth.The relationship between the formation mechanism of karst ground subsidence in this area.(4)Risk assessment of ground subsidence in mining area,suggesting prevention measures and suggestions.Based on the comprehensive analysis of the existing collapse pits,the influence weight of each influencing factor on the ground subsidence in this area is analyzed.The ArcGIS spatial analysis software is used to carry out the risk zoning and evaluation of the mining area and its surrounding subsidence area.The possible development trend of future ground subsidence in the area is obtained,and the possible hidden dangers in the surrounding area are analyzed and investigated,and corresponding protective measures,engineering control measures and monitoring measures are proposed,and finally the coordinated development of economic,social and resource environment is achieved.