Study On Dynamic Load Of Long-wall Mining Under Longwall In Room-column Goaf Of Hanjiawan Mine

The shallow-buried near-distance coal seam full-mechanized coal mining face,which is generated when the coal pillars of pillars and pillars pass above,has become a concrete engineering problem faced by the Yushenfu mining area.The instability of the coal pillars in the upper coal seam has a great impact on the mining of the lower coal seams,resulting in an accident of dynamic load on the working surface,which seriously threatens the safe and efficient production of the mines.In this paper,the 3-1 coal seam of the 2-2 coal seam of the Hanjiawan coal mine of the Hanbeiwan coal mine is taken as the engineering background,and theoretical analysis,numerical simulation and physical simulation are applied to the study,and the Hanjiawan Mine 3 is used.1 The process of coal seam mining working face 2-2 coal-column house-column pillars and the mechanism of dynamic load formation have been studied in depth.From the point of view of stress changes and strata migration,the reasons for the dynamic load pressure that may be caused by coal mining at room and pillar columns during coal mining are analyzed.The results of the study indicate that the dynamic load on the coal pillars of the pillar pillars at the working face is due to sudden large-scale instability of the pillar pillars leading to the occurrence of the key layers above them due to the influence of the lower coal seam mining and advanced bearing pressure.Leading faults and reverse rotation of key blocks will transmit overlying strata loads to the underlying rock structure,eventually leading to down-stabilization of the key blocks below.This is the root cau.se of the strong dynamic load pressure in the working face.The over-column pillars are caused by the rock-spinning instability of the overlying rock masses of the 2-2 coal seam,which results from the sudden release of overburden stress and coal pillar stress during the interval of the coal pillars.Under the coal seam working face,the phenomenon of dynamic load pressure in the pillar coal pillar group and the spacing coal pillars has great harm to the safe and high-efficient mining of the coal mine working face.Therefore,the study on the mechanism of its dynamic load rock pressure provides reference and technical solutions for the safety problems encountered by fully mechanized coal mining under close-range coal seam under the overlying chamber of the mine at Yushenfu coal mine.