运营期水下盾构隧道管片接缝张开度变化规律

Variation of segment joint opening of underwater shield tunnel in operation period

水下盾构隧道管片间接缝张开度对隧道防水及运营期结构安全有重要影响。以南京扬子江隧道结构健康监测系统中两个典型监测断面的接缝监测数据为基础,通过多元线性回归分析方法分析在两种不同地层组合下接缝张开度随水位、温度变化的规律;并对接缝张开度随水位变化的规律进行了有限元数值模拟,数值模拟结果与回归分析结果吻合较好。上述分析结果表明,纵缝张开度和横缝张开度随水位、温度的变化均呈现较好的线性关系,具体变化趋势如下:当盾构隧道穿越上砂下岩的上透下不透地层时,环内上半部分管片纵缝张开度随水位的增大而增大,受温度影响则相对较小;当盾构隧道穿越砂性全透水地层时,环内管片纵缝张开度随水位的增大而减小,受温度影响也相对较小;环间横缝张开度在上述两种地层下随水位、温度的变化趋势相同,均随水位增大而增大,随温度的升高而减小。

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.