大埋深盾构隧道管片结构受力特性实测分析

Experimental Analysis of Stress Characteristics of Segment Structure of Deep Buried Shield Tunnel

盾构法具有掘进速度快、扰动小以及自动化程度高等特点,但盾构隧道管片结构承受的高围压可能会导致接缝处混凝土接触面压溃,对整个隧道的安全形成危害。对此,以新建深圳机场至大亚湾城际铁路隧道建设项目为例,采用现场检测方式,对选取的盾构隧道断面布置混凝土应变计,用于实时监测管片拼装完成、盾尾脱环和壁后填充三个不同过程盾构隧道管片结构的受力变化情况。研究结果表明:盾构隧道管片结构在某些阶段处于三向受压状态,处于该阶段的管片结构比较安全,同时,断面施工对管片的影响范围大约在脱环之后10环范围内。该研究结果可为其他类似工程提供参考和借鉴。

The shield tunneling method is characterized by fast excavation speed,minimal disturbance,and high automation.However,the high confining pressure on the segment structure of shield tunnels can lead to the crushing of concrete contact surfaces at the joints,posing a threat to the overall tunnel safety.Taking the construction project of the Shenzhen Airport to Daya Bay intercity railway tunnel as an example,this paper conducted field testing to arrange concrete strain gauges on the selected sections of the shield tunnel to monitor the stress changes in the segment structure during three different processes:segment assembly completion,shield tail departure,and backfill grouting.The research results indicate that the segment structure of the shield tunnel is in a triaxial compression state at certain stages,making it relatively safe during those stages.Additionally,the impact of section construction on the segments extends to approximately 10 rings after the tail departure.These findings can serve as a reference for similar engineering projects.