Analysis On Support Technology Beside Roadway In Gob-side Entry Retaining Of "Three Soft" Inclined Coal Seam

This article through the theoretical analysis， a mechanical structure model ofinclined coal seam on gob-side entry retaining was set up， and earlier stage and laterstage rules of roof rock effect to the roadside support on conveyor roadway andventilation roadway gob-side entry retaining was respectively analyzed， the roadsidesupport resistance calculation formula on corresponding condition of gob-side entryretaining have been gained by the mechanics solution. According to the solutionformula，the selection of different support width，calculate the corresponding roadsidesupport resistance， thus choose the right roadside supporting method and determinedby supporting body size.According to the theoretical calculation results， design the roadside supportprograms of gob-side entry retaining for the XuYong coal mine S1134ventilationroadway and the WeiXin coal mine11902conveyor roadway with mining "three soft"coal seam. It has been combined supported with anchor+cable anchor+gunite in theroadway. and that stacked4m wide support body in the S1134ventilation roadside.Then mason3m wide support wall with precast concrete block in11902conveyorroadside. Rest to using the flexible template+pumping gangue concrete filling1.5mwide support. The proportioning tests of pumping concrete with mining waste gangue asaggregate were researched. It effectively improved the workability， greatly raised thecollapsed slump， and reduces the concrete set time and raises its forepart strength ofthe pumping concrete with1.0%mix amount the pumping aid. The concrete strengthincrease with water cement ratio decreases， but too much cement mix amount will leadto the higher cement hydration heat， so that the concrete will crack as its internaluneven contraction. Through the experiment， determined to meet the requirements ofthe pumping and strength gangue concrete filling materials， make full use of themining waste gangue， realize the comprehensive utilization of resources.Using three-dimensional numerical simulation software， the surrounding rockstress distribution and deformation in different supporting conditions on gob-side entryretaining were numerical simulation calculated.3D numerical simulation models onconveyor roadway and ventilation roadway gob-side entry retaining were respectivelyset up and calculated， the result show that，stress concentration appears both in theinternal roadside support body and the coal side deep within equal to the width of roadway on ventilation roadway gob-side entry retaining， and that stress concentrationappears only in the coal side deep， in the roadside support body is much lower. Mainbecause of that is affected to the angle of coal seam， it enhances the rotary andsubsidence of roof as its dead weight， lead to the subsidence is higher than conveyorroadway gob-side entry retaining， which result in the stress concentration onventilation roadway gob-side entry retaining is higher than conveyor roadway’s.Through the industrial test it shows that when uses the stacking bagging ganguesupporting method， the roof subsidence is high because of the bagging gangue haslarge shrinkage， and its strength is strengthened with the bagging gangue iscompacted， as a result the subsidence of roof tend to stationary. This support methodsubstantially meet the requirement of the roadway support， but it still need somerestoration measures for the high subsidence. When uses the masonry precast concreteblock method， because its high strength， the roof is controlled well in forepart， butit has not enough subsidence to adapt the rotary and subsidence of roof， due to thestress concentration in the support body is overload， lead to the support body iscrazed even destroyed， result in the roof has large subsidence in late stage. Thissupport method substantially meet the requirement of the roadway support， but it stillneed some restoration measures for the high subsidence.When uses the masonry precast concrete block method， because its high strength，the roof is controlled well in forepart， but it has not enough subsidence to adapt therotary and subsidence of roof， due to the stress concentration in the support body isoverload， lead to the support body is crazed even destroyed， result in the roof haslarge subsidence in late stage. Therefore， it plan to use the support method of flexibletemplate and pumping gangue concrete， the method unite the advantages of the bothsupport methods， and mechanization， high efficiency， low labor intensity，accommodate the requirement of high production and high efficiency.