Manifestation law of strong mine pressure in shallow-buried close-range coal seam working face through parallel coal pillar mining
Strong mine pressure and support accidents are prone to occur in the mining process of par-allel coal pillars in shallow buried close distance coal seam,which seriously affects the safe and effi-cient mining of the working face.Taking the 43207 working face of Yujialiang coal mine and the 2-2up 102 and 2-2up103 working faces of Shigetai coal mine as the background,the method of combining the-oretical analysis,physical simulation and field measurement analysis was adopted.According to the thickness of interval strata and the influence angle of coal pillar stress transfer,the criterion of stage di-vision through the coal pillar was put forward.The distribution characteristics of support working resist-ance in different stages of working face passing through parallel coal pillars under different inter-mining ratios G and hydraulic fracturing degree were analyzed.The results show that:due to the effect of coal pillar and inverted trapezoidal overburden structure,the average load of the support is the largest in the influence stage of the coal pillar,the second in the stage of entering the coal pillar,and the smallest in the stage of outing the coal pillar.The position of strong mine pressure is mainly concentrated in the in-fluence stage of coal pillar.The smaller the inter-mining ratio G,the greater the average working resist-ance when the working face is weighting during the mining stage of coal pillar.The ratio G=5.5 is 14.6％,14.2％and 23.5％higher than G=10 in the stage of entering the coal pillar,influence stage and outing stage,and the dynamic load effect is more obvious.The inter-mining ratio has little effect on the periodic weighting intervals,in general,the periodic weighting interval in the influence stage of the coal pillar is 1.6～2 times that of the other stages of coal pillar.The larger the periodic weighting inter-val,the larger the roof overhang length,which causes the obvious support load when the working face is weighting.According to the analysis of the mine pressure law of different hydraulic fracturing ranges in the coal pillar stage,the average load of the support after fracturing is reduced by 11.2％～15％com-pared with that without fracturing,and the weighting interval is reduced by 7.8％～20.3％.The effect of hydraulic fracturing is obvious,which effectively reduces the strong mine pressure risk of pillar min-ing.It provides reference for strong mine pressure control under similar mining.
万方数据
维普
