Acta Geodaetica et Cartographica Sinica ›› 2026, Vol. 55 ›› Issue (6): 1101-1115.doi: 10.11947/j.AGCS.2026.20250546

• Large-scale Engineering Infrastructure Surveying and Mapping and Underground Space Intelligent Perception • Previous Articles    

A segment joint multi-measure interaction index for shield tunnel recognition in RMLS point clouds

Ze YOU1(), Liying WANG1(), Yiwei YU1, Zhiwei QIN2, Chunxi XIE3, Yimo GENG1, Xinao LI1   

  1. 1.School of Geomatics, Liaoning Technical University, Fuxin 123000, China
    2.Natural Resources Satellite Application Technology Center of Liaoning Province, Shenyang 110031, China
    3.Institute of Surveying, Mapping and Geographic Information, China Railway Design Corporation, Tianjin 300251, China
  • Received:2025-12-29 Revised:2026-06-05 Published:2026-07-28
  • Contact: Liying WANG E-mail:youze1997@163.com;wangliyinglntu@163.com
  • About author:YOU Ze (1997—), male, PhD candidate, majors in intelligent processing and applications of LiDAR point clouds. E-mail: youze1997@163.com
  • Supported by:
    The National Natural Science Foundation of China(42571520);Joint Fund Project of Liaoning Provincial Natural Science Foundation(20240315)

Abstract:

Segment joints are critical weak points affecting the structural safety of shield tunnels, and their accurate recognition is essential for structural health monitoring. Rail-borne mobile laser scanning (RMLS) provides a high-quality data foundation for the recognition of segment joints. However, noise, occlusions, and uneven point cloud density in tunnels reduce the accuracy and robustness of existing methods. To address these limitations, this study proposes a shield tunnel segment joint recognition method based on the segment joint multi-measure interaction (SJMI) index. The method first removes clearly non-lining points using a cross-sectional ellipse fitting approach. Next, a SJMI is constructed by combining a bilateral wedge-fall geometric measure with an intensity residual measure, quantitatively capturing the distinctive characteristics of segment joints. Finally, the constructed SJMI index is used to sequentially recognize circumferential and longitudinal joints with high accuracy. Experiments on real RMLS point cloud data demonstrate that the proposed SJMI-based method effectively captures segment joint features, improves the recognition of actual joints, and suppresses noise and false positives. Quantitative evaluation shows that for circumferential joints, the IoU, recall, and precision reach 90.21%, 90.32%, and 99.84%, respectively, while for longitudinal joints, the corresponding metrics are 94.52%, 95.89%, and 98.23%. Compared with the current best-performing method, the IoU of circumferential and longitudinal joints increased by 2.25 percentage points and 7.96 percentage points, respectively, clearly demonstrating the significant accuracy advantage of the proposed method. In addition, the SJMI-based approach maintains strong robustness in complex tunnel environments and provides a reliable technical basis for the digital operation and maintenance of shield tunnels, segment joint anomaly detection, and structural health assessment.

Key words: shield tunnel, segment joint, rail-borne mobile laser scanning, point cloud, multi-measure interaction, clustering

CLC Number: