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Water inrush from the excavation face often occurs in the current shield construction of metro tunnels. In this study, the discontinuity of shield tunnel lining and the interaction between the tunnel segments, the grouting layer, and the surrounding rock are considered. Based on the 3D nonlinear contact theory, a hybrid model of the shield tunnel is constructed. Considering the uid-solid coupling e ect of water and soil, the in uences of di erent water head di erences on the mechanical performance and deformation of segments and joints in the shield tunnel are studied. e water gushing from the excavation face leads to vertical convergence of the cross-sectional area of the shield tunnel, and joint opening and dislocation result in sharp decrease of the waterproof capacity of joints. Meanwhile, the stress in the vicinity of segment joints increases sharply, and local cracks occur in the segment lining. e axial force, shear force, and bending moment in the joint bolt are also signi cantly increased. Based on the current metro standard and the computational results in this study, an emergency control criterion is put forward by means of controlling the discharge of water: the water head di erence over the excavation face is required less than 4.6 M.

Safety is a key objective of construction management, but construction safety management is complex due to various types of technical and management factors. If critical factors can be identified and corresponding measurements can be adopted, it will be more direct and effective to improve safety performance. In this paper, by using the system thinking method, construction safety management is considered as a system and decomposed into six subsystems and related management factors. The fuzzy fault tree analysis method was used to build a reliability analysis model and reveal the failure probabilities of factors in the safety organization management subsystem. Through a questionnaire survey conducted in Wuhan, China, the pivotal importance degrees and average occurrence probabilities of basic factors are figured out. On the basis of that, nine critical factors of the safety organization management subsystem are identified and corresponding improvement measurements are proposed. More, a case study of Hangzhou underground railway tunnel collapse accident in 2008 is conducted, which verifies that the framework of construction safety management based on system thinking can be a useful tool for identifying faults or failure reasons of construction safety management.