The Research On Strata Behavior Characteristics Of Thick Coal Seam Across Coal Pillar Mining Face

This passage based on the existing rock mechanics and stope rock control theory and a large number of previous experimental studies,It analyzes the work of the longwall single layered artificial caving coal in the three mining areas of Baigou Coal Mine by theoretical analysis and similar simulation.The characteristics of mine pressure phenomenon in the mining face of the old mining area are analyzed as follows:1?through the recovery of the face through the residual mining area when the overlying strata of the collapse zone,fracture zone and bending subsidence zone analysis.It is understood that the height of the "longitudinal zone" of the overburden is increased.Especially the height of the caving zone and the fissure zone is more obvious,and the stability of the fracture zone is affected by the influence of the mining,which leads to the enhancement of the ground pressure phenomenon and the decrease of other strata pressure.2?It analysis of the stress characteristics of the coal pillar,it is understood that the coal pillar undergoes three processes in the process of re-mining,followed by:(1)supporting the pressure in front of the mining face and the other side of the pillar bearing pressure does not affect each other stage.(2)support the pressure in front of the face and the other side of the pillar support the pressure of mutual influence stage.(3)the pressure on both sides of the coal pillars superimposed on each other and lead to coal pillar instability stage.In particular,attention should be paid to the third stage,coal pillar instability will seriously affect the safety of the face.3?It show that the peak pressure in the coal pillar area is the largest,and the stress concentration on both sides of the coal pillar is greater than that in the middle of the coal pillar.The bearing pressure in the residual mining area is not obvious,and the bearing pressure is greatly affected by the structural instability of the coal pillar.Especially when the coal pillar is completely collapsed,the overburden layer completely collapses to the additional load generated in the goaf More obvious.The pressure concentration of the coal pillar area before the recovery is obvious,and there is obvious advance bearing pressure in the front of the coal wall during the advancement of the mining face,but after the hydraulic support is completely pushed,the goaf The pressure is reduced or even reduced to zero,the main reason for this phenomenon is due to the coal pillar overlying strata after the occurrence of steps after the collapse of the pillars on both sides of the formation of "inverted trapezoidal" structure,the structure of the beam structure of two The side is subjected to a greater supporting effect,so that the load generated by the lower empty area is reduced.By the principle of interaction,we can see that in the residual mining area and the goaf area,the support structure of the beam above the coal pillar is formed,and the upper beam plate is forced to the residual area in front of the working face,and the coal pillar collapses The rock formation as a whole collapses,so that the stress on the left side of the coal pillar is larger than that on the left side of the pillar.4?Through the analysis of the existing theoretical analysis of the hydraulic support and the surrounding rock interaction system,the load of the hydraulic support in the residual mining area and the load of the hydraulic support in the coal pillar area are analyzed respectively.When the pillar is located in the coal pillar area,the hydraulic support in the pillars bear the maximum load,the maximum load increment may reach the hydraulic support average load of 9-10 times the impact on the safety of the mining face a greater impact.