Response Relationship between Longitudinal Joint Opening and Convergence Deformation of River Crossing Shield Tunnel

Tunnel convergence can directly reflect the safety status of the tunnel structures, which is an important factor affecting the normal operation of the subway. Based on the Nanjing Yangtze River large section shield tunnel, a single-ring segment numerical refinement model is established. The accuracy and feasibility of the numerical model are verified by the health monitoring data of on-site joint opening. The relationship between longitudinal joint opening and convergence, and the influence of bolt preload and segment assembly angle on convergence are studied. The results show that: (1) The longitudinal opening joint is the key factor of circumferential convergence of the shield tunnel, and the rotation of the segment around the joint is the main form of convergence. (2) For large deformations (＞8‰D), increasing the bolt preload is not recommended to be the primary means to control convergence. (3) The obtained "longitudinal joint opening-convergent deformation" fitting formula can be used to approximately estimate the longitudinal joint opening of arch-crown under different convergence of arch waist in round gravel and pebble fully permeable stratum.