Supporting Of Mining Gateway’s Surrounding Rock Under The Thick Coal Seam

China is a coal production country, the coal resources are mainlydistributed in the central and western regions, because of the difference ofgeological conditions in each area, the development mode is alsodifferent.The extra thick coal seam is very common in the area of InnerMongolia and the seam depth is relatively shallow, so the inclined shaft iscommonly used.The problem of thick coal seam mining have to be settledurgently because of the rapidly increasing demand for coal in our country withrapid economic development. The top-coal drawing technology can greatlyimprove the production capacity of the mine,but the relevant issues arealso presented,for example the roadway support.The better development ofseam joint and lower ohesive strength in mining roadway roof result in the rockbolting reaction on wall rock didn’t achieve the desired results when thethickness of coal seam has been more than ten meters,at the same time the stresstransfer is not uniform and the effect is not obvious.According to this kindof roadway surrounding rock conditions,we need to findthe reasonable, effective control measures to solve the problem in the mine roadway,and the significance is important.The paper combine with roadwaysurrounding rock conditions of F6204haulage gate of Bu Lian Gou coal mineand research on the roof rock breaking condition.Put forwardthe reasonable support scheme by theoretical analysis and numericalsimulation,the deformation monitoring of roadway surrounding rock isevaluate all these claims.This paper mainly studies the following content:(1) Through the field investigation, geological data collection andanalysis,the occurrence characteristics of coal seam6#and characteristics ofexcavation was understood,the excavation roof surrounding rock’sconstituent--coal seam with tens of meters thick was revealed,the fragilelithology of the excavation roof surrounding rock caused the rock bolting to thesurrounding rock’s reaction force did not achieve the desired results, the stresstransfer is not uniform and the effect is not obvious;(2) Analysing of the feature of high seam roof surrounding rock, andimitating the rock bolting rope supporting in numerical simulation,indicate thatfor rock bolting rope supporting,surrounding rock stress has to be increased andevenly and effectively transfer to the surrounding rock to ensure surroundingrock’s bearing capacity into full play,and the supporting effect achieve thedesired purpose;(3) By using the conformal transformation in complex variable function,rectangular tunnel and area are projected to another coordinate plane of the unit circle, the stress and strain of each position of rectangular tunnel on the unitcircle are solved;(4) The rectangular tunnel roof surrounding rock that in line with the actualwas derived according with the moment balance,unstable region of surroundingrock was ascertained,and damage area of surrounding rock was ascertainedaccording to plastic zone distribution under the condition of unequal stressof lubinniete, l.e. the length of rock bolt shall be2.4m; cable length shouldbe greater than7.8m.(5) Based on the above theoretical analysis and the feedback of staff atthe scene,specific factors disturbing support way in transfort crossheadingswere analyzed.According to the characteristics of high seam roof surroundingrock, specific ideas of roadway supporting were designed.By using themethod of numerical simulation, we compared the scheme’s supportingfunction.Finally,we ascertained best excavation supporting scheme under thecondition of high seam roof: high strength bolt+H beam+anchor+metalnetwork supporting;(6) To check site construction effect, to monitor roadway surroundingrock deformation for a period of2.5months, the final analysis indicate thatat the early stage of roadway excavation or after supporting high seam roof sinksin2mm/d speed and after the observation period of fortieth days,the roof is ina relatively stable period,and the roof deformation amount is about75mm andremained basically unchanged after the observation period. The result shows that the supporting design is reasonable and effective.Thestudy not only to a certain extent to solve the Bu Lian Gou mine F6204haulagegate support problems, but also provides a more accuratereference for other mining6#coal seam roadway, ensure the6#coal-bedstoping work carried out smoothly. At the same time, the study also provides asuccessful engineering analogy reference case for other similar geologicalconditions of coal mine roadway support.