Study On The Pre Support Technology Of Tunnel Roof Under Unfavorable Geological Condition

Tunnel pipe roof reinforcement technology in tunnel excavation before,in a position above the tunnel face,drill a hole through the drainage pipe,mechanical equipment with grouting holes,with a certain angle into the hole,and then by machine pressed into the cement slurry,and solid rock,making a stable and be able to withstand the pressure of rock umbrella protection ring pre formed in the top of the tunnel,under the environment of tunnel construction can guarantee the construction safety and high efficiency.On the basis of the five mountain tunnel in Hubei,Enshi Province,this paper studies the pre support technology of pipe shed:(1)summarize the nature,characteristics,harm and corresponding treatment measures of unfavorable geological conditions,and analyze and study the principle,function principle and mechanical characteristics of the pipe roof support technique;(2)to establish a 3D numerical model of Wufengshan mountain tunnel is simulated using the finite element analysis software Midas/GTS,analysis of the tunnel with pipe roof support of tunnel surrounding rock deformation,study of pipe roof reinforcement technology can effectively transfer the loose rock pressure in poor geological conditions,control the deformation of the surrounding rock in the tunnel near the surface the maximum bending moment and deflection,pipe roof;pipe tunnel roof supporting the settlement value along with the advance of present the trend of convergence of the excavation(3)pipe roof reinforcement system supporting design parameters were analyzed,to study the effects of pipe roof length,the optimum value of pipe roof layout and supporting parameters on the deformation characteristics of surrounding rock of tunnel;(4)the three-dimensional numerical model is established by the finite element method,and the influence of pipe grouting on the surrounding rock of tunnel is analyzed.