基坑零距离上跨盾构隧道的环境影响与控制  

Environmental Impact and Control of Zero Distance Shield Tunnel over Foundation Pit

作　　者：施有志 刘旭东 赵朋 靳增 SHI You-zhi;LIU Xu-dong;ZHAO Peng;JIN Zeng(School of Civil Engineering and Architecture, Xiamen University of Technology, Xiamen 361024, China;China Railway First Bureau Group Xiamen Construction Engineering Co., Ltd.,Xiamen 361000, China)

机构地区：[1]厦门理工学院土木工程与建筑学院,厦门361024 [2]中铁一局集团厦门建设工程有限公司,厦门361000

出　　处：《科学技术与工程》2022年第18期8110-8121,共12页Science Technology and Engineering

基　　金：厦门市建设局科技项目(XJK-2021-9);福建省自然科学基金(2022J01130362)。

摘　　要：针对地铁车站出入线明挖法施工,基坑零距离上跨下卧正线隧道的影响及控制问题,以国内首例基坑零距离上跨地铁隧道工程——厦门地铁某停车场与正线重叠段为依托,采用三维数值模拟并结合现场实测,研究出入线明挖基坑施工对下卧隧道的影响,以及采取变形控制措施的效果。结果表明:开挖紧邻下卧隧道的区域(第5~8区段)引起的地表沉降量和隧道上浮量分别占地表最终沉降和隧道最终上浮量的91.46%和90.53%;隧道纵向轴力从-606.4 kN/m增长到-1939 kN/m,是基坑施工的关键阶段;通过对下卧盾构管片拉紧装置加固,在管片内部用8根14b槽钢将管片纵向连接,加强管片连接整体性和稳定性,可以起到抑制不均匀沉降的作用;位于基坑范围外的隧道管片不用反压堆载,基坑范围内采用线性加载的方式,可以较好地控制下卧隧道的上浮量。施工实践表明,采取的隧道管片内堆载反压以及管片纵向加固等综合变形措施合理可靠,管片最大上浮量为17.7 mm,处于允许范围,盾构隧道结构安全稳定。In view of the zero distance foundation pit crossing the underlying main line tunnel in the open cut construction of subway station entrance and exit line influence and control problems.The research based on the domestic first case of zero distance foundation pit crossing subway tunnel project,a certain parking lot of Xiamen Metro and the overlapping section of the main line as a case,to investigate the influence of open cut foundation pit construction of entrance and exit line on the underlying tunnel by using three-dimensional numerical simulation and field measurement,and the effect of deformation control measures.The results show that the ground settlement and tunnel uplift caused by excavation in the area adjacent to the underlying tunnel(section 5~8)account for 91.46%and 90.53%of the final ground settlement and tunnel uplift respectively.The longitudinal axial force of tunnel increases from-606.4 kN/m to-1939 kN/m,which is the key stage of foundation pit construction.By reinforcement the segment tension device of the underlying shield machine,eight 14b channel steels are used longitudinally in the interior side,and connect segments to enhance the integrity and stability,which can settlement a restraining the uneven.The tunnel segment exterior side the foundation pit does not need back pressure surcharge,and the linear loading method within the foundation pit can better control the floating amount of the underlying tunnel.The construction practice shows that the comprehensive deformation measures such as the surcharge back pressure in the tunnel segment,and the longitudinal reinforcement of the segment are reasonable and reliable.The maximum floating amount of the segment is 17.7 mm,within the allowable range,and the shield tunnel structure is safe and stable.

关 键 词：地铁出入线 明挖基坑 下卧盾构 零距离近接施工 隧道内堆载反压 钢条加固 

分 类 号：U451[建筑科学—桥梁与隧道工程]