Stability Study On Surrounding Rock Of Tunnel Through Coal Strata Of Chenggui Passenger Special Line

Tunnels through coal strata of Chenggui passenger special line are faced with lager deformation of surrounding rock as well as coal and gas outburst.Relying on two typical tunnels through coal strata of the passenger special line,by using literature search,field investigation theoretical analysis,monitoring measurement of construction site and numerical simulation analysis.The stability of surrounding rocks and coal uncovering outburst prevention technology are researched.The main research contents are as follows:(1)Through the collection of information about lager information of weak surrounding rock and collapse of tunnel through coal strata,to understand the security risks faced by the tunnel through coal strata and its influencing factors.(2)Crown settlement,horizontal convergence,surrounding rock pressure,early support concrete stress,internal force of steel arch,axial force of bolt and contact pressure between two linings of the Gao Po tunnel were tested to summarize the characteristics of force and deformation of surrounding rock and supporting structure and analyze the cause of lager deformation of weak surrounding rock in coal strata,evaluating the stability and safety of surrounding rock and early support structure,proposing the improvement scheme of early support structure.(3)It simulates the Gao Po tunnel excavation with the finite element software ABAQUS,and analyses the characteristics of force and deformation of surrounding rock,the distribution of internal force of the early support structure and the space-time effect of tunnel excavation.The security and safety of surrounding rock and early support structure are evaluated based on the comparative analysis of numerical simulation results and on-site monitor results.(4)The stability of the rock pillar between the coal seam and excavation face was analyzed by using the Catastrophe Theory,the C5 coal seam in Yu Jingshan tunnel have three different dip angle,through analysing surrounding rock stress and displacement caused by uncovering coal of benching tunneling construction method,upper middle three steps method and CD method by using the finite element software ABAQUS to summarize the effect of the stability of surrounding rock caused by the reserved thickness of rock,proposing the minimum reserved thickness of safety rock and uncovering coal method of different dip angle coal seam.