毗邻深基坑地铁隧道激光扫描测量及整体变形规律研究

Study on Laser Scanning Measurement and Overall Deformation Law of Metro Tunnel Adjacent to Deep Foundation Pit

随着地铁及市政设施网络化程度日益增高,毗邻地铁隧道进行深基坑开挖工程日益增多。基坑开挖所造成的环境影响特别是对既有运营隧道的影响一直广受关注,其核心在于控制其变形的发展。然而,受限于测试技术,过往未能就基坑开挖过程中隧道整体变形规律有过深入的探讨。以实例工程项目为背景,基于激光扫描技术,通过点云椭圆拟合,分析了隧道收敛椭圆长短轴在基坑开挖前后的变化情况,研究深基坑开挖所引起的邻近地铁隧道整体变形发展规律,提出了隧道开挖过程中的监测物理量,为后续地铁监测及维护控制提供技术支撑。

With the increasing degree of network of metro and municipal facilities,the excavation works of deep foundation pit adjacent to metro tunnel are increasing.The influence of foundation pit excavation on the environment,especially on the existing operated tunnels is always widely watched.Its core is to control the development of its deformation.However,limited by the test technology,there is no further discussion on the overall deformation law of tunnel in the excavation process of foundation pit.Taking an engineering example as the background,based on the laser scanning technology and through the point cloud ellipse fitting,the variation of the long and short axes of tunnel convergence ellipse before and after the excavation of foundation pit is analyzed.The development law of the overall deformation of metro tunnel caused by the excavation of adjacent foundation pit is studied.The monitoring physical quantity in the excavation of tunnel is put forward.The above provides the technical support for the follow-up monitoring and maintenance control of metro.