比對地面光達技術與影像掃描系統進行隧道變形監測之研究

Compared Ground LiDAR Technology with Image Scanning System on Tunnel Deformation Monitoring

隧道變形監測為工程建設中重大項目。傳統的作業方式為影像掃描系統（GRP5000），精度雖高，但成本較大，非一般民間業界可以承擔負荷。2019年交通部公路局例行在蘇花公路作的隧道測量維護工程，本研究特別選當中16座隧道中的（一）澳花隧道（二）仁清隧道（三）和清隧道（四）無名隧道為研究區域，利用地面光達掃描及點雲資料處理的方法進行隧道量測，用以比對傳統影像作業模式，藉此探究地面光達應用於隧道測量的可行性及精度分析。實驗成果顯示:，本研究中點雲資料經拼接計算後，點與點之間平均距離約在7-10mm之間。對於寬度低於10mm之裂縫，較難判斷。
相較於影像掃描系統作業，地面光達耗時較長，且點雲資料因為硬體的規格，精度受限，但由於成本較低，且作業便利，可視為作隧道局部監測得替代方案。光達技術在工程測量上應用，具有相當的可行性。建議在精度要求不甚高的情況之下，地面光達仍可作為隧道變形監測的輔助角色。

Tunnel deformation monitoring is a major project in engineering construction. The traditional operation is using Image Scanning System. Although it has the high accuracy , its cost is too high, and civil unit can’t afford to carry out. In 2019, Ministry of Transportation and Communications routinely carried out the tunnel survey and maintenance project on the Suhua Highway. In this study, we selected 4 tunnels from the 16 tunnels : (1) Aohua Tunnel (2) Renqing Tunnel (3) Heqing Tunnel (4) unnamed tunnel , as the research area. Using 3D LiDAR scanning technology and point cloud data processing for tunnel measurement to compare with the Image Scanning System(GRP 5000) operation mode. In order to explore the feasibility and accuracy analysis of the Ground LiDAR for tunnel measurement. In this study, the average distance of points can be achieved at 7- 10 mm after the point cloud data stitching. but it is difficult to judge cracks with a width of less than 10 mm.
Compared with Image Scanning system, the Ground LiDAR takes longer time, and the accuracy of point cloud data is limited due to hardware specifications. However, because of the lower cost and conveniently operation, it can be regarded as an alternative for assisting in monitoring of the tunnel. The application of LiDAR technology in engineering measurement is quite feasible. Under precision requirements is not too high, It is suggested that ground LiDAR can still be used as a supporting role for tunnel deformation monitoring.