Research Shallow Seam Mining Of Overburden Strata Movement And Surface Subsidence Law

In order to gain a deeper understanding of the overburden movement and ground subsidence caused by shallow coal seam mining under mountainous landforms,the thesis takes the mining of the face of Pusa Coal Mine in Nayong County,Guizhou Province as the engineering background,applying theoretical analysis,computer simulation and physical simulation methods,Systematically study the law of overburden collapse and surface subsidence caused by the slope of the mountain,and analyze the particularity of the overburden movement during the mining of the face.The research results can be obtained under the similar geomorphic conditions in Nayong County,Guizhou Province Provide some reference for coal mining.The thesis combines the specific geological data of the mine,constructs an elastic thin plate model,and applies mechanical analysis to analyze the movement state,breaking form and breaking step of the basic top pressure during the mining process of shallow buried coal under the mountain.The breaking form and breaking step of the basic top cycle are analyzed,and the rationality of the formula is verified.The factors influencing the pressure step of the shallow coal seam working face are analyzed.Computer numerical simulation was used to simulate the subsidence process of the roof block during the mining of the working face.The basic roof stress changes during the mining of the shallow coal seam working face were analyzed.The movement of the overburden rock caused by mining and the surface settlement were studied.: The peak value of stress concentration in the mining face shows a downward trend,the peak value of the first roof breaking stress is the highest;the periodic breaking distance in the mining face is 20 m,which is consistent with the theoretical calculation.The surface subsidence trend and the basic roof subsidence trend during the mining process of the working face indicate that the coal mining under the mountainous terrain is greatly affected by the surface,the subsidence value of the ground slope is greater,the subsidence trend is more obvious,and the horizontal movement value is greater.According to the physical geological data of the mine,a physical similarity simulation was carried out.The micro-earth pressure box and the three-dimensional digital measurement system were used to measure the stress,strain and displacement during the mining of the working face.The process gradually rose to the peak,and the basic top period breaking distance was consistent with numerical simulation and theoretical calculations,which was about 20 m.The stress changes show that the peak stress concentration of the rock layer shows a downward trend,which is the same as the numerical simulation.At the same time,the surface subsidence and the horizontal movement of the surface are also the same as the numerical simulation results,which proves the accuracy of the physical similarity simulation.In the process of coal seam advancement,the overburden stress is attenuated.The reason is that the coal seam overburden is a gradually smaller amount,so the surface subsidence presents a "teapot" type,indicating that the left rock formation has a larger bending deformation.The right side is obvious.