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姚文博, 贺少辉, 张嘉文, 刘夏冰, 郭炎伟, 马腾. 热力盾构隧道先盾后井施工衬砌接头变形机理与控制[J]. 岩土工程学报, 2018, 40(6): 1056-1065. DOI: 10.11779/CJGE201806011
引用本文: 姚文博, 贺少辉, 张嘉文, 刘夏冰, 郭炎伟, 马腾. 热力盾构隧道先盾后井施工衬砌接头变形机理与控制[J]. 岩土工程学报, 2018, 40(6): 1056-1065. DOI: 10.11779/CJGE201806011
YAO Wen-bo, HE Shao-hui, ZHANG Jia-wen, LIU Xia-bing, GUO Yan-wei, MA Teng. Deformation mechanism and control technology of segment joints during process of shield tunneling prior to shaft excavation in a heat-supplying tunnel project[J]. Chinese Journal of Geotechnical Engineering, 2018, 40(6): 1056-1065. DOI: 10.11779/CJGE201806011
Citation: YAO Wen-bo, HE Shao-hui, ZHANG Jia-wen, LIU Xia-bing, GUO Yan-wei, MA Teng. Deformation mechanism and control technology of segment joints during process of shield tunneling prior to shaft excavation in a heat-supplying tunnel project[J]. Chinese Journal of Geotechnical Engineering, 2018, 40(6): 1056-1065. DOI: 10.11779/CJGE201806011

热力盾构隧道先盾后井施工衬砌接头变形机理与控制

Deformation mechanism and control technology of segment joints during process of shield tunneling prior to shaft excavation in a heat-supplying tunnel project

  • 摘要: 先盾后井是热力盾构隧道建设中一种高效经济的施工工法。结合中国首例大断面热力盾构隧道工程,基于纵向等效连续化模型和弹性地基梁理论,对施工过程中衬砌接头受力特征和变形机理进行了分析,并提出控制措施;然后建立了衬砌接头全断面接触面单元数值模型,对控制效果进行分析和评价;最后通过现场监测,得到了不同施工阶段管片纵向轴力及接缝变形规律。研究结果表明:先盾后井工法施工中,衬砌接头变形分为两个阶段:基坑开挖及管片拆除,其中管片拆除为接头变形的主因,基坑施工中,基底卸荷产生的负弯矩作用于隧道上,导致邻近竖井管片底部轴力减小、环缝张开,拆除基坑内管片时,作用于端头管片的残余盾构推力和螺栓预紧力消失,导致管片纵向轴力进一步衰减,环缝二次张开;根据现场监测结果,提出的对邻近竖井的管片纵向拉紧并复紧连接螺栓,进行混凝土铺底及衬砌背后二次注浆的控制措施能够有效控制轴力损失,减小接头变形,施工中环向接缝最大张开量3.51 mm,满足隧道防水要求;采用全断面接触面单元建立的数值模型可以较为精确地模拟施工中管片接头力学行为,其结果可作为控制效果评价参考依据。

     

    Abstract: The shaft excavation following the shield tunnel is an efficient and economic method in the construction of heating shield tunnel. Based on the first large cross-section heating shield tunnel project, the stress characteristics and deformation mechanism of segment joints at different construction stages are analyzed using the longitudinal equivalent continuous model and the elastic foundation beam theory, and the control measures are proposed. The numerical model for the full face interface element is established, and the control effect of the measures is analyzed and appraised. Finally, the change laws of longitudinal stresses and segment joints at different construction stages are measured through field monitoring. The results indicate that the deformation of segment joints can be divided into two stages in the shaft excavation following the shield tunnel: foundation excavation and segment removal, and the segment removal is the main reason. The negative bending moment formed in the excavation of shaft affects the bottom segments of tunnel, and the disappearing of remnant shield force caused by segment removal enlarges the loss of longitudinal stress and opening of segment joints. According to the monitoring results, the control measures including longitudinal tension segment and retightening the bolt, pouring concrete in the tunnel bottom and secondary grouting behind the lining can effectively control the loss of longitudinal stress, and reduce the deformation of joints. The maximum opening of segment joints is 3.51 mm, meeting the waterproof requirements of tunnels. The numerical model based on the full face interface element can be used to simulate the mechanical behaviors of the segment joint in construction, and the results can be used as reference for evaluation of the control effects.

     

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