The Study On Overburden Failure And Surface Deformation Law Of Mining Coal In Laozhanggou Coal Mine

In this paper,according to the specific geological conditions and mining methods of Laozhanggou coal mine,the influencing factors of the overburden destruction and surface deformation of coal mining are analyzed,and the influence weight of each influencing factor is quantified using the analytic hierarchy process.The theoretical experience formula,numerical simulation and site survey were used to study the overburden damage and surface deformation caused by coal mining in Laozhanggou Mine.The main work and conclusions of the study are:(1)According to the analytic hierarchy process,the main influencing factors of the overburden destruction and surface deformation of the Laozhanggou coal mine are obtained,and the deep coal seam thickness and lithology of the overburden rock are the two main control factors.And by establishing an ideal model,it is concluded that the depth of the coal seam is inversely proportional to the size of the surface,and the thickness of the coal seam is proportional to the size of the surface deformation.The depth of the coal seam has the greatest impact on the surface deformation;the harder the lithology of the overlying coal seam,,the surface deformation The smaller,the harder the roof of the coal seam,the smaller the surface deformation.(2)The surface deformation basin and working surface layout of Laozhanggou coal mine are generally the same.The largest settlement is at the center of the goaf.There are multiple tensile cracks around and inside the deformed basin,and no collapse pits appear.At the beginning of mining,the main stress map changes from saddle type to "W" type to wave type.When mining repeatedly,the main stress shape is a saddle type with low middle and high sides.With the increase of excavation length,the height of overburden of coal seam and the height of overburden destruction of coal seam 4-3 are all increasing.The tensile damage of coal seam is concentrated at the mining center of two coal seams,and shear failure occurs frequently.At the place where the coal wall and coal pillar are located,the rock formation is entirely convex on...