Study On Asymmetric Distribution Characteristics Of Surrounding Rock Stress In Right Angle Trapezoidal Tunnel Of Inclined Coal Seam

The reserves of inclined coal seam in Western China account for about 10.1%of the recoverable reserves,and the coal quality is good,and it is of high mining value.But during the mining process of inclined coal seam,the stress distribution of tunnel surrounding rock is asymmetrical due to the influence of inclination,which brings great difficulties to roadway stability control and supporting engineering.In this paper,taking the two mining area of Shi Jiaojing coal mine of Shenhua Ningxia coal group,Shi Jiaojing coal company as the engineering background,the asymmetric distribution characteristics of the surrounding rock of the right angle trapezoid tunnel are studied by means of theoretical analysis,numerical simulation calculation and indoor similar simulation test,which can provide a scientific basis for the selection of supporting scheme.The main work and conclusions are as follows:(1)through theoretical analysis can be seen:right angled trapezoid roadway in inclined coal seam excavation in rock roadway,right angled trapezoid stress distribution is asymmetric characteristics,and factors and the angle of coal seam size,rock mass structure and tectonic stress and so on,mainly for help,two lane and top roof surrounding rock stress distribution and deformation have obvious difference,resulting in two for asymmetric extrusion,dislocation and deformation,and the emergence of the phenomenon of asymmetric drum bottom,caused the floor and track to the side oblique,to the regular use of roadways caused great influence.(2)in order to further analyze the asymmetric features,with two Shitanjing mine as the engineering background,using the FLAC3D finite difference method,the horizontal displacement,different longwall roadway right angled trapezoid in different stress conditions of vertical displacement,vertical stress and horizontal stress and plastic zone were studied.Results show that the dip angle is bigger,the asymmetric stress and deformation is more obvious,the greater the stress,asymmetric extrusion,dislocation and deformation is more obvious.The right side of the surrounding rock(low help)is the key position of the deformation and destruction of the surrounding rock of the trapezoid tunnel of inclined coal seam.(3)the two dimensional similar material simulation test method is used to reproduce the asymmetric characteristics.Through comprehensive analysis can be seen:the asymmetric characteristics and theoretical analysis and numerical simulation are similar,the subsidence of roof increases with the increase of angle,stress,but about two of the displacement of roadway for negative convergence,and the displacement is greater than the left right for help,it still needs further study.(4)the two similar material simulation test method research of inclined coal seam roadway should be no more right angled trapezoid reported stress distribution of asymmetric,and due to the limitation of school conditions,found the model test in the research process,similar model material ratio,the size of the loading mode,more or less will have an impact on the test results,test analysis and summary for the next step of the model test provides abundant experience and reference.