Stability Analysis And Advance Reinforcement Of TBM Tunnel Face In Broken Surrounding Rock

Under the background that the mining of mineral resources,underground tunnels and other underground projects in China are increasingly developing towards the deep stratum,the high ground stress and complex unfavorable geology of the deep stratum have brought great challenges to the development and construction of underground space.Among them,the deep tunnel is faced with the difficulties of support under high ground stress,large convergence deformation around the tunnel,broken surrounding rock in the fault fracture zone,easy falling of arch crown,even tunnel collapse and other major disasters.In the process of tunneling,the stability of the heading face plays a decisive role in the steady progress of the tunnel.Therefore,it is of great significance to study the stability of tunnel heading face in fault fracture zone for practical engineering.Combined with the complex geological conditions of the F12 fault of Xianglushan tunnel,the tunneling of TBM with broken surrounding rock is studied by means of similar simulation test,numerical simulation and theoretical calculation,the stability of the tunneling face of TBM in the F12 fault fracture zone is evaluated,and the movement law of advance grouting reinforcement slurry is analyzed to provide reference for the project site.The main conclusions are as follows:(1)By means of similar simulation,the tunneling of TBM in the fault fracture zone was simulated,and the morphological changes of the tunneling face and the surrounding tunnel during the process of TBM crossing the fracture zone were observed.It was found that the tunneling face of TBM crossing the fault collapsed,and the horizontal displacement of the tunneling face reached 41 mm.The stress change of the arch crown during the process of TBM advancing was analyzed.(2)By means of numerical simulation,the changes of stress field,displacement field,plastic zone and strain energy density field in the process of TBM crossing the fault are analyzed.It is found that the displacement of heading face in the fault is the largest,the stress of surrounding rock is much higher than its own bearing capacity,the depth of plastic zone is up to 6m,and the energy is accumulated.(3)Based on the limit equilibrium method,the stability coefficient of the heading face is calculated,and the instability of the tunnel face is obtained.The effects of different slurry cohesion after solidification,different surrounding rock load and grouting range on the stability coefficient of the heading face are analyzed;At the same time,based on the multi field coupling mechanics and indoor rotating viscosity test,a numerical model considering the changes of the dual physical properties of slurry and surrounding rock is established in combination with the numerical simulation method.The movement law of advanced grouting in broken surrounding rock is studied.The effects of cement slurry with different water cement ratio,different grouting pressure and different initial permeability on the grouting range are analyzed.The reference of grouting parameters is given in combination with the calculated value of limit equilibrium method.Figure 46 Table 5 Reference 79...