Strata Behavior Law of Coal Mining Face with Short Distance to Above Seam Passing Through Upper Seam T Crossing Coal Pillar

In order to analyze the strata behavior law of No.21306 coal mining face passing through upper seam T crossing coal pillar in Daliuta Coal Mine,the theoretical analysis and the FLAC3Dnumerical simulation was applied to analyze the function mechanism of the T crossing coal pillar from the point of the inner stress distribution of the coal pillar.The results showed that the strata behavior of the mining face under the upper strike coal pillar would be in a symmetry distribution,and the support loading in the mining face would be generally higher than that under the upper goaf.During the mining face passing through the upper inclined coal pillars,there would be three stage different strata behavior features respectively under and out of the upper inclined coal pillars and right under the coal pillars.The upper inclined coal pillar influenced to the strata behavior in the coal mining face would be obviously larger than that of the strike coal pillar.Due to the stack influence role of the strike pillar and inclined coal pillar,the effect degree of the cross section of the T type coal pillar to the coal mining face pressurized would be between the strata behaviors.The concentrated stress distribution on the coal pillar would be the reason to cause the stratum behaviors law of the coal mining face under the up strike coal pillar and in under inclined coal pillar stage different in other area.The dynamic stratum pressure of the coal mining face out under the inclined coal pillar stage was caused by the relative rotary movement of the unstable key block structure above the coal pillar.