Risk analysis of double shield TBM construction accident induced by tunnel deformation

Tunnel boring machine (TBM) is widely used in deep tunnel at present; and the accidents caused by tunnel deformation become more and more common. Therefore, it is very necessary to analyze the risk of accidents induced by tunnel deformation in advance. Considering the mutual effect of tunnel face and shield rear support, convergence-confinement method and risk analysis theory are applied to calculate the pressure imposed by surrounding rock on shield. Meanwhile, according to the magnitude of pressure imposed on shield, the specific influence of tunnel deformation on TBM construction is estimated; and the consequence of accidents risk is divided into five ranks. Deformation risk evaluation matrix for TBM is proposed by the combination of occurrence probability with consequence rank; and then the risk rank can be determined by the proposed evaluation matrix and existing risk acceptance criterion. In the end, the risk analysis of double shield TBM construction accident in west route of South-to-North Water Transfer Project is conducted by using the research results.