盾构隧道结构响应特征及接缝刚度分析

Structural response characteristics of shield tunnels and analysis of joint stiffness

掌握运营期水下盾构隧道的结构响应规律是研究隧道整体稳定性的重要组成部分。基于武汉长江隧道健康监测系统,获得了隧道结构一年(2022年4月-2023年4月)的应变和接缝监测数据,研究对比了江中断面和岸上断面的应变与接缝开度的响应规律及其差异,提出了一种计算管片环缝法向刚度的方法。研究结果表明:(1)岸上断面的管片应变、接缝张开度的平均年度幅值均显著大于江中段断面;(2)温度对岸上断面管片的应变和接缝开度影响大于江中断面;(3)管片环缝应力-张开度曲线与岩石结构面压缩荷载-位移曲线类似,不同测点位置的应力-张开度曲线差异显著;多个测点的平均法向刚度在其张开阶段和闭合阶段比较近似,但是江中断面的环缝法向刚度明显大于岸上断面。

The structure response of the underwater shield tunnel during operation is important in studying the overall stability of the tunnel.Based on the health monitoring system of Wuhan Yangtze River Tunnel,the strain and joint monitoring data of the tunnel structure over one year(from April 2022 to April 2023)were obtained.In this study,the response patterns and differences in strain and joint opening between the under-river section and the bank section were compared,and a method for calculating the normal stiffness of segment circumferential joints was proposed.The results show that:(1)the average annual amplitudes of segment strains and joints opening of the bank sections are much greater than that of the under-river section;(2)The influence of temperature on the strains and joints opening of the bank sections are greater than that of the under-river section;(3)The normal stress-joints opening curves of the circumferential joint are similar to the normal stress-displacement curve of the rock joints,but the curve shape differs at different monitoring positions.The average normal stiffness at multiple monitoring points is similar during both the opening and closing stages.The normal stiffness of the circumferential joint in the under-river section is significantly greater than that in the bank section.