Fluid-structure coupling model of shield tunnel considering seepage of segmental joints
Peng Yicheng1,3 Gong Chenjie2,3 Ding Wenqi3 Lei Mingfeng2 Shi Chenghua2 Wang Yuanye2
1. Shanghai Electric Power Design Institute, Shanghai 200025, China； 2. Central South University, Changsha 410075, China;
3. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China
Abstract：Leakage usually occurs at the segment joint of tunnel lining-Long-term seepage may lead to the change of load distribution and stress mode, which endangers the structural safety. Aiming at the situation that it is difficult to accurately simulate the mechanical properties of shield tunnel under joint leakage, a new simulation analysis method is proposed. Based on the developed joint connection element, the mechanical deformation response of shield lining joint was analyzed, and the joint seepage was numerically simulated by the secondary development of finite element software. The key point is the iterative analysis on the dynamic change of contact stress and external water pressure caused by gasket opening. Hence, the numerical model of fluid-structural coupling of shield tunnel considering segment joint seepage is established. Based on the practical case of Shanghai metro shield tunnel, the deformation mechanism and ground settlement law of tunnel under different levels of seepage, seepage flow, joint stiffness and waterproof performance are analyzed. The results show that: the location of segment joint and the seepage volume affect the internal force of the lining structure. In detail, the bending moment significantly increases, while the axial force slightly decreases. The seepage at the waist joint has the greatest influence on the internal force of structure. The deformation of tunnel structure increases with the increase of seepage flow, and the relationship is basically positive. The influence of waist, bottom and top joint on the lateral movement and deformation of the tunnel decreases successively. There is a positive relationshipbetween tunnel structure and surface settlement with the increase of segment joint seepage. When seepage occurs at the top joint, the surface settlement is the largest, but the tunnel settlement is the least. When seepage occurs at the bottom joint, the surface settlement is the least, but the tunnel settlement is the largest. This research is expected to be useful to the study of the fluid-structure coupling model of shield tunnel.
