基于三维激光点云的隧道掌子面挤出位移场高精度监测方法

High-precision Monitoring Method for Extrusion Displacement Field of Tunnel Face Based on 3D Laser Point Cloud

为实现快速、自动化、高精度的隧道掌子面整体监测,基于三维激光点云提出了一种掌子面挤出位移场监测方法,其中包括简单易行、精度高的刚体参照引入方法和隧道非刚体掌子面变形路径追踪技术。首先基于平面应变假设提出了一种基于初期支护纵向方向的稳定刚体参照;然后基于局部小变形刚体假设和二维连续小波表达初期支护的波动特征,并使用多级迭代配准算法修正初期支护的位置,实现刚体参照的配准;最后使用点云法向量聚类算法分割隧道掌子面,并基于局部小变形刚体假设和路径追踪算法获取每期掌子面的位移路径,得到掌子面挤出位移场。对所提方法的有效性在高速公路隧道进行了试验验证,并将估算的掌子面挤出位移结果分别与传统刚体参照下有变形路径追踪和无变形路径追踪的挤出位移进行了定性对比分析,同时又与全站仪监测的挤出结果进行了定量对比分析。结果表明:所提方法能够高精度地监测隧道掌子面的挤出位移场,监测结果与全站仪监测结果对比的中误差为0.83 mm。所提方法可用于掌子面稳定性的监测分析和地质灾害有效预警,从而提高隧道开挖过程的安全性。

To achieve rapid,automated,and high-precision overall monitoring of the tunnel face,a method based on three-dimensional(3D)laser point clouds is proposed to monitor the tunnel face extrusion displacement field.This includes a simple and highly accurate rigid-body reference introduction method and nonrigid face deformation path-tracking technology for the tunnel.First,a stable rigid-body reference based on the initial support longitudinal direction was proposed based on the assumption of plane strain.The wave characteristics of the initial support were expressed based on two-dimensional continuous wavelet transform,assuming a local small-deformation rigid body.A multilevel iterative registration algorithm was applied to correct the position of the initial support and achieve rigid body reference registration.Finally,the point-cloud normal vector clustering algorithm was used to segment the tunnel face.Based on the assumption of a small local deformation rigid body,the path-tracking algorithm was used to obtain the displacement path of each tunnel face,resulting in the extrusion displacement field of each tunnel face.The results of this study were experimentally verified in highway tunnels.The tunnel face extrusion displacement estimated using the proposed method,was qualitatively compared with that obtained with and without deformation path tracking under traditional rigid body reference.In addition,a quantitative comparative analysis was conducted using the extrusion results monitored by the total station.The results indicate that the research findings of this study can accurately monitor the extrusion displacement field of the tunnel face,and the root mean square error with respect to total station monitoring was 0.83 mm.The results of this study can be used to monitor and analyze the stability of the tunnel face and effectively warn of geological disasters,thereby improving the safety of the tunnel excavation process.