激光扫描技术在隧洞轮廓时变监测中的应用

Application of laser scanning technology to monitoring of tunnel cross-section with time

基于隧洞全断面三维激光扫描技术与三维点云后处理分析技术以及自行开发的隧洞轮廓时变的MATLAB分析程序,提出了一种深埋隧洞断面处理技术,解决了深埋隧洞全断面点云数据采集和批处理(配准、去噪、连续切片和断面分析等)的问题,探讨了可能导致隧洞断面轮廓时变的因素,并将该技术应用于锦屏地下实验室全断面轮廓的监测和分析中,结合现场地应力条件、工程破坏案例、数值模拟结果以及结构面分布情况解译了深埋硬岩隧洞断面轮廓的时变特征。基于点云的隧洞断面轮廓时变特征是隧洞施工过程、力学响应过程的综合反映,是岩体力学特性、结构控制作用的综合表现,对围岩力学行为反分析研究具有重要支撑作用,是第一手客观的定量数据源。

Based on a 3D laser scanning technology,post-processing software and MATLAB procedure,a processing method of monitoring the variations of the tunnel cross-section profile is developed.This method solves the problems of the collection and batch processing(i.e.registration,denoising,serial section and cross-section analysis)of point clouds in deeply-buried tunnels.The factors that may lead to the changes in tunnel cross-section with time are discussed.The proposed processing technology is then applied to the cross-section monitoring and analysis at Jinping Underground Laboratory(CJPL-Ⅱ).The change characteristics of the cross-section at CJPL-Ⅱ with time are investigated based on the in-situ stress conditions,failure cases,numerical results and joint distributions.The change characteristics of the cross-section at CJPL-Ⅱ are the results of combined actions by the high geostress,excavation induced unloading and rigid joints.The change characteristics of the tunnel cross-section profile with time based on point clouds,as a first-hand objective and quantitative data source,are a comprehensive reflection of tunnel construction and mechanical response processes,as well as a comprehensive expression of the mechanical properties of rock mass and the structural control effect,which provides significant support for the back analysis study on the mechanical behavior of surrounding rock.