Numerical simulation and application of large deformation law of chamber pilot roadways in deep soft rock

Dynamic simulation and comparative study through use of finite difference method with FLAC^3D program, combination with field measurement method for deep soft rock chamber-pilot-roadway's construction and support technology. The variation law of rock stress and strain by the effects of chamber size changes are analyzed; the deformation law of interaction between rock and support system in the tunnel construction process are analyzed. On this basis, identified the reasonable parameters of chamber excavation and support systems. Flow deformation can be generated enough by Pilot chamber in situ, release a part of the Geo-stress and make full use of the carrying capacity of rock itself, then Geo-stress redistribute the stress to reach a new equilibrium state, so that the pressure are released effective and control, it is benefit to permanent support. Since expanding outside area is in the low stress lap of soft rock that disturbance in deep rock can be avoided and the deformation of roadway can effectively controlled also.