Research On Formation Mechanism Of Ground Cracks By Steep Seam Mining Of Shitun Coal Mine In Jiangsu

The impact of steep seam mining on the ground surface has been an important part of the theoretical study of mining subsidence,because of the special nature of its own conditions,damage to the ground in the form of the scale and the scale of the more than the level or the more complex and more inclined coal seam.Surface cracks are the most common and most severe forms of surface damage in the steeply inclined coal seam,the research on the formation mechanism of surface cracks found that the steep seam mining is a dominant factor in the formation of surface cracks,and the complex geological structure has an important influence on the formation of surface cracks and crack size.Especially in the mining subsidence area in the presence of a fault,the surface is more prone to step shaped cracks.The spatial position relation of coal seam and fault is different,and the mechanism of fracture formation is different.The paper took steep seam coal mining of Shitun coal mine in Jiangsu cause surface cracks as an example,the engineering geological conditions and the details of the surrounding areas of the steeply inclined coal seam are investigated,the formation mechanism of surface cracks is discussed on the basis of analysis of the mining and fault conditions of steeply inclined coal seam,the surface crack is caused by the mining disturbance and the activation of the fault.In view of the technical conditions of steeply inclined coal seam and the actual strata structure in coal seam,the similar physical simulation experiment method and FLAC^3D numerical simulation method are used to study the coal seam mining.Through the analysis of the surface subsidence curve,the surface subsidence law is revealed,and the surface subsidence of the fault outcrop is determined.In the physical simulation experiment,through the analysis of the relationship between fault line and the direction of coal seam,combined with theoretical knowledge of the influence of fault on mining subsidence,to determine the form of the influence of the fault on the subsidence,the simulation experiment confirms this kind of situation.Through establishing fault and without fault of the two models,the analysis of the effect of the fault on the surface,according to the subsidence curve,to determine the level of the fault outcrop will produce a step shaped crack.A comparison between the surface subsidence curve and the surface subsidence curve of the coal seam inclined surface with the FLAC^3D simulation is calculated,confirmed the correctness of the numerical simulation results.Impact on footwall rock mass in the mining of deeply inclined coal seam,to make the life of the fault plane and move,resulting in a step shaped crack in the outcrop.The results of the research are of guiding significance for the similar complex geological conditions.