管棚对顶推地道桥路面沉降抑制作用分析研究  

Analysis and Research on the Inhibitory Effect of Pipe Shed on the Settlement of Top Push Underpass Bridge Pavement

作　　者：何亮 潘世强 杨飞 HE Liang;PAN Shiqiang;YANG Fei(Hunan Hengyong Expressway Construction and Development Co.,Ltd.,Hengyang,Hunan 421651,China;Hunan Communications Research Institute Co.,Ltd.,Changsha,Hunan 410114,China)

机构地区：[1]湖南省衡永高速公路建设开发有限公司,湖南衡阳421651 [2]湖南省交通科学研究院有限公司,湖南长沙410114

出　　处：《公路工程》2024年第4期74-79,169,共7页Highway Engineering

基　　金：湖南省交通运输厅科技项目(202214)。

摘　　要：为研究地道桥顶推施工全过程中管棚对路面沉降的抑制作用,结合某市政次干道下穿机场高速通道工程实例,建立了无管棚和Φ402管棚的三维有限元数值仿真模型,采用“分层分块开挖方法”和“生死单元方法”来模拟顶推施工过程中既有路面沉降规律,以及管棚自身的应力和变形特征。结果表明:所建立的三维数值仿真模型较好地模拟了管棚超前支护下的路面沉降,计算结果与现场监测较为吻合;在顶推施工过程中,采用Φ402管棚可以有效抑制路面沉降,尤其是进口附近的路面沉降,最大沉降基本满足<20 mm的沉降要求;管棚变形分4个明显的分段特征,地道桥结构左侧刚度小,右侧刚度大,管棚表现为明显的空间扭曲状态。为更好地控制地表位移,左侧管棚间距可适当加密,右侧管棚可适当稀疏,顶进结束后,应及时对地道顶部进行注浆处理,从而减少路面的总沉降量。研究结果可以为管棚超前支护下桥式盾构顶进施工提供参考借鉴。To study the restraining effect of pipe sheds on road surface settlement during the entire process of jacking bridge construction,a case study was conducted on a municipal secondary road underpass project beneath an airport expressway.A three-dimensional finite element numerical simulation model was established,both without a pipe shed and with aΦ402 pipe shed.The"layered block excavation method"and"birth and death element method"were employed to simulate the settlement patterns of the existing pavement during the jacking process,as well as the stress and deformation characteristics of the pipe shed itself.The results indicated that the established 3D numerical simulation model effectively simulated the pavement settlement under the advanced support of the pipe shed,with the calculated results closely matching the field monitoring data.During the jacking construction,using aΦ402 pipe shed effectively restrained road surface settlement,especially near the entrance,with the maximum settlement generally meeting the requirement of being less than 20 mm.The deformation of the pipe shed exhibited four distinct segments,with lower stiffness on the left side and higher stiffness on the right side of the bridge structure,causing the pipe shed to display a noticeable spatial torsion.To better control surface displacement,the spacing between pipe sheds on the left side can be appropriately reduced,while on the right side it can be increased.After jacking is completed,grouting treatment at the top of the tunnel should be carried out promptly to reduce the total amount of pavement settlement.The research results provide a reference for the jacking construction of bridge-type shield tunnels under advanced support of pipe sheds.

关 键 词：管棚 桥式盾构 数值模拟 刚度 路面沉降 

分 类 号：U445.462[建筑科学—桥梁与隧道工程]