Regularity Of Coal-pressure Manifestation In Layered Fully Mechanized Caving Face With Steeply Dipping Seam And Extra Thick Seam

In the process of layered mining of thick seam with steeply dipping seam,the strata pressure appearance of the lower working face is obviously different from that of the general long wall working face.The surrounding rock of the working face is affected by two times of mining,so the roof management of the working face is difficult.Therefore,it is of great practical significance to study the ground pressure law of the working face under the fully mechanized sublevel caving with steeply dipping seam and extra thick coal seam for the high-yield and efficient production of Dongxia coal mine.This paper comprehensively adopts numerical simulation analysis,theoretical analysis,on-site mining pressureobservation and other methods,combined with the current theoretical results of steeply dipping seam mining and layered mining,studied the layered comprehensive The stress distribution law of surrounding rock in layer mining under the open pit,the roof structure and deformation and failure characteristics of the face in the lower layer and the law of rock pressure appearance in the face.The results show that due to the recovery of the upper layer 35219-1 working face,the surrounding rock structure of the layered fully mechanized caving face is changed,and the stress release of the rock layer of the lower layer working face produces regional deformation and failure.The destruction depth of the lower region tends to be greater than that of the middle and upper regions.This also affects the mining of the lower layer working face,which in turn affects the mechanical state and migration characteristics of the surrounding rock in the stope.According to the different overburden stru cture,the 35219-2 working face can be divided into overburden solid coal area in the upper part and influence area of goaf in upper layer face in the lower part along the tendency.The main load of the bracket in zone overburden solid coal area is only the pressure of direct jacking weight and basic jacking.The "bracket-surrounding rock" system is relatively stable,the working resistance changes are small,and there is no obvious pressure.Due to the influence of the upper layered gangue collapse stacking structure,the "support-wall rock" structures in the inclined areas of influence area of goaf in upper layer face area are different.This causes the pressure on the working face to have a time sequence,and the pressure on the middle of the working face occurs before the lower part.The values of Incoming pressure duration tend to show the central collapsed filling area>the upper unconnected top area>the lower sliding filling area.Therefore,roof management should be carried out according to the different characteristics of the two regionsThe research in this paper can guide the actual production of 35219-2 layered fully mechanized caving face.And it has certain reference significance for the safe and efficient mining of working face with similar conditions.