| The construction of tunnel and other infrastructure in some areas has to go over the top of the coal seam and even through the coal seam.The mining of coal seam has a certain effect on the safety of the facilities.And the steep inclined coal seam has the characteristics of big dip angle,complicated geological condition and unique mining method,which determines the complexity of the influence of its mining on the surface and above the structure.Therefore,the strata failure and surface movement caused by steep seam mining are significantly different from those of horizontal coal seam.Although it has accumulated valuable experience in theoretical research and practice in the past,it has not yet formed a more mature theoretical system,especially the prediction of the influence of the mining of steep coal seam on the movement and deformation of the tunnel.Therefore,developing the study on failure mechanism of roof strata and calculation of the sinking value of the tunnel in steeply inclined coal seam mining mining has important theoretical significance and practical engineering value.In this paper,in view of the complex geological conditions and roof stress characteristics of steep seam mining,the mechanism of roof failure and movement in steep seam mining is studied through the establishment of the mechanics model of roof rock strata.At the same time,according to the characteristics of tunnel overlay and stress,the subsidence calculation model of the steep inclined seam mining under the tunnel is constructed.Through the theoretical analysis and the finite element numerical simulation method,the subsidence value of the tunnel is predicted.The main contents are as follows:(1)Starting with the description of the deformation and destruction of the rock strata mining in the near horizontal and gently inclined coal seam,by summarizing the geological structure characteristics and mining methods of the steep inclined coal seam,the stress,deformation and failure law of the roof strata in the steep seam mining are emphatically analyzed.The stress model of the roof of the steep seam is set up,and the roof rock of the goaf is regarded as a beam with a certain support form,then the beam is subjected to the joint action of lateral force and axial force,and the mechanical model of the beam is established.At the same time,using the mechanicstheory and the energy theory,the bending and sliding problems of the roof rock are studied,and the deflection curve equation and the slip distance equation of the roof rock in the steep seam mining are obtained.(2)On the basis of the characteristics of the steep seam mining,the moving model of the roof rock of the steep seam is built,and the failure law of the roof bending of the steep seam is further studied.The slip of roof strata in steep seam mining is discussed,and the minimum span and maximum extent of rock failure under the limit condition are obtained.(3)According to the characteristics of the tunnel,the influence of the overlying strata pressure on the tunnel subsidence is analyzed on the one hand,and the influence of the mining on the sinking of the tunnel on the other side is studied on the other.The total sinking value of the tunnel is calculated.(4)Based on the actual situation of a tunnel,the approximate mechanics calculation model is set up,and the maximum subsidence value of the tunnel due to the steep seam mining is predicted through theoretical analysis and numerical simulation. |
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