Numerical Simulation And Analysis Of Surrounding Rock Failure Mode Of TBM Gripper During TBM Tunneling

Large formation or buckling failure of tunnel surrounding rock will easily occur for the TBM construction under weak and broken formation conditions. The problems such as the gripper failed or unstable supported gripper can cause TBM unable to tunneling. In this paper, the numerical simulation method is used to carry out systematic research on this problem. The main research contents and results are as follows:(1) Analyzed and summarized the research achievements of TBM gripper and tunnel surrounding rock interaction of both domestic and overseas, based on the review of large amount of relevant literature. On the whole, the research of TBM tunneling gripper supporting force is currently deficient. The estimation of gripper supporting force is mainly based on the engineering experience or the empirical formula. Thus, more detailed research should be made, for the failure mode of tunnel surrounding rock during the TBM tunneling process.(2) Established a simulation model, by using numerical modelling analysis software GDEM, which combine both finite element and discrete element method. Aims to analysis the deformation and failure mode of tunnel surrounding rock during the TBM tunneling process, the design load can be calculated from the empirical formula of gripper supporting force. There are two failure modes (compression-shear failure and shear failure) occur under the action of both gripper positive pressure and the axial shear stress.(3) By using the continuum finite element software ABAQUS, comprehensively analyzed the interaction between the TBM gripper and tunnel surrounding rock and the deformation and failure mode of surrounding rock, with the consideration of surrounding rock strength, surrounding rock grade, tunnel depth and tunnel diameter etc. Then the calculation result is compared with the former GDEM software.(4) Analyzed and compared the variation range and trend of unilateral TBM gripper supporting force under four surrounding rock conditions, based on the data collection and systemization of realistic measured data of TBM tunneling gripper supporting force during construction process. Then, the interaction law between the TBM gripper supporting force and surrounding rock conditions will be summarized.The research results in this paper have important guiding significance for the calculation of TBM gripper bearing capacity and the field construction under complex geological conditions.