Laser Scanner Tunnel Thickness Monitoring
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Solution Overview
Problem
Current methods for controlling concrete thickness during spraying in tunnel construction lack precision, leading to overuse of material and inefficiencies, as they do not provide real-time feedback or dynamic display of thickness variations, making it difficult to adjust the spraying process effectively.
Innovation Solution
A system utilizing LiDAR or laser-based measurement technology for real-time thickness monitoring, combined with a display system that projects thickness information as color maps or isolines, allowing for continuous or on-demand updates, enabling accurate adjustments during both additive and subtractive processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional surveying methods with steel rods or indicators are used to control concrete thickness, then the measurement can be performed after execution, but the precision and real-time feedback are insufficient leading to material overuse
Solution Approach 1:
The system performs a preliminary scan of the tunnel surface before concrete spraying to establish reference coordinates and target thickness values. This preliminary action enables real-time thickness monitoring during spraying by comparing current surface position against the pre-established target model, allowing operators to adjust spraying immediately to avoid both over-spray and under-spray material waste
Solution Approach 2:
The system implements continuous real-time feedback by repeatedly scanning the tunnel surface during concrete spraying and calculating thickness deviations from the target model. The color-coded display provides immediate visual feedback to operators showing areas of over-spray (red), correct thickness (green), and under-spray (blue), enabling dynamic adjustment of the spraying process to minimize material waste while maintaining precision
2Reliability
If thicker layers are sprayed to ensure design requirements are met, then the reliability of meeting minimum thickness is improved, but material consumption increases and excess material removal is required
Solution Approach 1:
The real-time feedback system continuously monitors concrete layer thickness during spraying and provides immediate visual indication to operators. The color-coded display (red for over-spray, green for correct thickness, blue for under-spray) enables dynamic adjustment of spraying rate and nozzle position, ensuring minimum thickness requirements are met reliably while avoiding excessive material application that would require removal
Solution Approach 2:
The system enables dynamic control of the spraying process by providing real-time thickness information that allows operators to continuously adjust spraying parameters. This dynamic adaptation ensures that the concrete layer thickness is maintained within acceptable ranges throughout the spraying process, achieving reliable compliance with minimum thickness requirements while optimizing material consumption
3Loss of information
If conventional tunnel scanners are used for 3D geometric reconstruction, then the surface can be measured, but the results are displayed only after reconstruction leading to delayed feedback and inability to correct thickness in real-time
Solution Approach 1:
The system performs continuous scanning and real-time processing of tunnel surface geometry during the concrete spraying operation. Instead of batch processing after completion, the system continuously acquires surface data, calculates thickness deviations, and updates the visual feedback display in real-time, ensuring that thickness information is always available without time delay to enable immediate corrective action
Solution Approach 2:
The system implements immediate feedback by processing scan data in real-time and displaying thickness information on-screen during the spraying operation. The color-coded thickness map is updated continuously, providing operators with current thickness status without delay, enabling them to adjust spraying parameters immediately based on actual measured conditions rather than waiting for post-processing
4Measurement precision
If steel rods or indicators are placed before spraying for thickness control, then the measurement reference is established, but the method is complicated and requires highly qualified resources
Solution Approach 1:
The system replaces complex mechanical measurement systems (steel rods, physical indicators, manual surveying equipment) with optical laser scanning technology. The laser scanner non-contactively measures surface geometry by emitting and receiving light, eliminating the need for physical thickness indicators and manual measurement tools, thereby reducing device complexity and eliminating the requirement for highly qualified surveying resources while maintaining measurement precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise, real-time monitoring and adjustment of concrete thickness, reducing material waste and operational costs by providing immediate feedback to operators, enhancing the accuracy and efficiency of the spraying process.
Implementation Method 1
a laser scanner, adapted to carry out a first scan of an initial surface before a concrete spraying
Data Source
Figure 1A~1C
Figure 2~3
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AI summary
The present invention relates to a material spraying monitoring/surveying method comprising the step of first scanning a surface of an object to obtain a first data matrix, wherein said first data matrix is defined by 2 angles α(0), β(0) and a distance d(0) from the device, spraying said material onto the previously scanned surface of said object, second scanning of the sprayed surface of said object to obtain a second data matrix defined by 2 angles α(t), β(t) and a distance d(t) from the device, processing the first and second matrices to obtain a processed data matrix defined by 2 angles α(t), β(t) and a distance difference Δd(t), comparing the distance difference Δd(t) with a target distance difference Δd displaying an information pattern representing the comparison result on said surface of said object and in real time, wherein the with information pattern represents the deviation between the target distance difference Δd and the real time measured and processed distance difference Δd(t) along the whole scanned surface.