Calculation Method of Tunnel Over-Under Excavation Based on Point Cloud Data
Journal Title: Urban Mass Transit - Year 2025, Vol 28, Issue 5
Abstract
[Objective] During tunnel construction using the drilling and blasting method, over-excavation and under-excavation issues are always unavoidable. To accurately identify over-under excavation positions and calculate the over-under excavation, an excavation calculation model based on tunnel longitudinal section lines is proposed for this issue. [Method] Point cloud data collected by the 3D laser scanner are pre-processed and the tunnel central axis is extracted. The 3D Delaunay algorithm is applied for curved surface reconstruction of point cloud data, and the transverse and longitudinal section lines are extracted on the curved surface. Over-under excavation areas are calculated by comparing actual cross-section profile lines with theoretical profile lines. Combined with cubic spline curve fitting results of longitudinal section lines, the over-under excavation areas per unit radius are obtained, thereby conducting analysis of the functional relationship between over-under excavation areas and tunnel mileage. [Result & Conclusion] Combining transverse section over-under excavation area with cubic spline curve fitting results of longitudinal section lines, and the method for calculating over-under excavation volumes by integrating along longitudinal section lines, the volume element changes along the tunnel mileage direction in terms of volume element shape are taken into account. The minimum unit of over-under excavation volumes is simplified into a curved prismoid, enabling over-under excavation volume calculation through integration. When applied to the actual tunnel over-under excavation analysis, under identical volume element division condition, the proposed calculation model demonstrates higher calculation accuracy than other calculation methods, while intuitively displaying tunnel over-under excavation situation through chromatograms and contour maps.
Authors and Affiliations
Zhipeng ZHANG, Wenming CHENG, Run DU, Hetian CHEN
Keywords
Related Articles
- EP ID EP766704
- DOI 10.16037/j.1007-869x.2025.05.026
- Views 21
- Downloads 0
Mechanical Performance Analysis of Design Scheme for High-speed Train Obstacle Deflector with Built-in Aluminum Honeycomb Covered Energy Absorber
［Objective］ The OD (obstacle deflector) serves as a primary passive safety device on high-speed trains, effectively clearing obstacles between the wheels and the tracks. However, conventional OD designs do not meet the...
Influence of Back-Support Shear Wall for Shield Launching on the Mechanical Characteristics of the Reaction Frame
Objective Due to the limited space available at the shield launching site, the restricted size of the reaction frame cannot provide sufficient shield launching reaction force on its own. Therefore, it is necessary to des...
Comparative Analysis of Calculated and Experimental Current Carrying Capacities of Rail Transit Aluminum Alloy Conductive Rails
Objective AAC (luminum alloy conductive) rails are widely used in rail transit power supply systems. However, a significant deviation often exists between the calculated and tested values of the permissible current carry...
Safety Assurance Methods for Urban Rail Transit Virtual Coupling System Engineering
[Objective] To systematically identify the safety requirements of urban rail transit virtual coupling systems, and provide technical references for system safety assurance and the third-party assessment, it is necessary...
Advanced Prediction Method for Shield Tunneling Cutterhead Torque Based on WaveNet Network
Objective Cutterhead torque is a crucial parameter that characterizes the safety of shield tunneling and the operating status of equipment. To address the difficulties in cutterhead torque prediction and excavation param...