适应任意形状铁路隧道LiDAR点云的断面差异分析方法

针对三维激光扫描技术在铁路隧道超欠挖分析和收敛分析等应用中如何能对任意形状隧道LiDAR点云进行断面差异分析的关键问题,本文提出了一种适应任意形状铁路隧道LiDAR点云的断面差异分析方法。该方法先建立铁路隧道设计断面统一模型,提出实测断面点与设计要素对应关系判定方法,对从隧道LiDAR点云中提取出的断面在铁路隧道设计断面统一模型中逐点确定所对应的设计要素,并计算出断面在对应设计要素上的径向投影点到设定的起算高程面与设计断面左侧交点的弧长,根据弧长对断面进行排序,最后根据设定的采样步长对有序的断面进行采样得到实测断面,进而计算出实测断面相较于设计断面的偏差量。通过3组具有代表性的不同断面隧道模拟点云数据对提出的算法参数最佳取值进行试验,试验结果不仅给出了算法参数的最佳取值,也论证了本方法可以对任意形状铁路隧道LiDAR点云进行断面差异分析。

Section Difference Analysis Method for Railway Tunnel with Arbitrary Shape Based on LiDAR Point Cloud

Aiming at the key problem of 3D laser scanning technology in the analysis of tunnel overbreak and underbreak analysis and convergence analysis,the cross-section difference analysis method for LiDAR point cloud of arbitrary shape railway tunnel is proposed.This method first establishes a unified model of railway tunnel design section,and proposes a method for judging the correspondence between measured section point and design element.the correspondence for the section extracted from the tunnel LiDAR point cloud is determined point by point in the uniform model of the railway tunnel design section.And the arc length of radial projection point of the cross-section on the corresponding design element to the intersection of the set starting elevation surface and the left side of the design section is calculated,the points of the section are sorted according to the arc length,and finally according to sampling step The section of the sequence is sampled to obtain the measured section,and then the deviation of the measured section from the design section is calculated.The optimal values of the proposed algorithm parameters are analyzed by three sets of representative different-section tunnels simulated point cloud data.The experimental results not only give the best value of the algorithm parameters,but also demonstrate that the method can be applied to arbitrary shape railways.