The opening of joints between segments of the underwater shield tunnel has a great influence on tunnel waterproofing and the structural safety in operation period. Based on the joint monitoring data of two typical monitoring sections in the structural health monitoring system of Nanjing Yangtze River Tunnel

through the multiple linear regression analysis method

the effects of water level and temperature on joint opening in different stratum combinations were analyzed. And the variation of joint opening with water level was simulated by finite element method. The numerical simulation results are in good agreement with the regression analysis. The results of the above analysis show that the longitudinal joint opening and the transverse joint opening have a good linear relationship with water level and temperature as follows: when the tunnel crossing the permeable stratum of sand for the upper half tunnel section and the impermeable stratum of sandstone for the lower half section

the opening of the longitudinal joint increases with the increase of water level and is relatively less affected by temperature; when crossing the whole permeable sandy stratum

the opening of the longitudinal joint decreases with the increase of the water level and is relatively less affected by the temperature; regardless of which of the two strata the shield tunnel crosses

the transverse joint opening increases with the increase of water level and decreases with the increase of temperature.