Characteristics And Risk Assessment Of Surface Subsidence In A Mining Area In Shanxi Province

Taking a large mine in Shanxi as the research object,the characteristics,influencing factors and formation mechanism of the surface subsidence in the mining area are studied through field investigation and mathematical statistics,and then the risk assessment of the surface subsidence is completed based on the GIS platform.Get the following main understanding:(1)The area of the mining area is 83.6126km~2,and the geological environmental problems of the mine include geological disasters,aquifer damage,terrain and landform landscape destruction,and the occupation and destruction of land resources.The results show that the mine geological disasters are mainly ground cracks,the eastern aquifers in the mining area are seriously damaged,the landform landscape and the land resources are seriously affected by the coal gangue and the surface subsidence.Generally speaking,the geological environment in the eastern part of the mining area is serious.(2)The surface subsidence of mining area is mainly ground fissure,collapse pit and building damage.Starting with the basic geological conditions and mining technology,the distribution law of surface subsidence and its controlling factors are analyzed.The results show that the coal seam mining induces surface subsidence,the geological conditions and mining conditions are the control factors of surface subsidence,and the hydrologic conditions aggravate the surface subsidence.(3)The sliding ground fissures are widely distributed in the mining area,with emphasis on the analysis of its influencing factors and formation mechanism.The results show that the sliding ground cracks in the mining area are large and the lower side falls obviously,which is seriously affected by the shape of the slope.The roof caving of the goaf causes the stress redistribution and interlayer dislocation,and the upper strata of the upper slope slide down to form a tensional crack zone,and this slow deformation forms a ground crack after a long time and repeated open mining disturbance.(4)The results of the risk assessment of the surface subsidence in the mining area show that the high risk area is mainly distributed in the new mining area in the middle of the mining area and the shallow mining area with shallow buried depth in the eastern part of the mining area.The middle danger zone is mainly distributed in the old goaf which tends to stable in the East.The low risk area is mainly distributed above the goaf which has a large buried depth and no repeated mining,and the very low risk is distributed in the unexploited area.(5)Evaluation of the vulnerability of surface subsidence in mining area shows that the high vulnerability area is mainly distributed in the industrial land near the national road.The secondary high vulnerability area is mainly distributed in the southeast corner town of the mining area.The middle vulnerable area is distributed in various settlements,and the forestland and unused land are widely distributed,so the area of the low vulnerability area is larger.(6)The results of the risk assessment of the surface subsidence in the mining area show that the high risk area mainly concentrates on the two sides of the southeast national road of the mining area,mainly for the concentrated area of industrial land.The buried depth of the underground coal seam is shallow and repeated more mining.At present,the surface of the area tends to be stable.After the treatment,the ground load should be avoided as far as possible,so as to avoid the aggravation of the surface subsidence.The study on the surface subsidence and risk assessment of the mining area provides an important theoretical basis for the subsequent development and restoration of the mine,and is of great significance for other mines that have not been developed or started to prevent the mining subsidence and reduce the loss of surface subsidence.