Open Access

ARTICLE

Design of a Wireless Measurement Instrument for Tunnel Anchor Rod Length

Mengqiang Yu¹, Xingcheng Wang¹, Chen Quan¹, Mingxin Sun¹, Yujun Yang², Xiaodong He¹, Wu Sun^2,*, Pengfei Cao^1,*

1 School of Information Science and Engineering, Lanzhou University, Lanzhou, 730030, China
2 Department of Science and Technology Innovation Management, Gansu ZhiTong Technology Enginnering Detection Consulting Co., Ltd., Lanzhou, 730050, China

* Corresponding Authors: Wu Sun. Email: ; Pengfei Cao. Email:

(This article belongs to the Special Issue: Non-contact Sensing in Infrastructure Health Monitoring)

Structural Durability & Health Monitoring 2025, 19(5), 1127-1143. https://doi.org/10.32604/sdhm.2025.067069

Received 24 April 2025; Accepted 20 June 2025; Issue published 05 September 2025

Abstract

Accurate measurement of anchor rod length is crucial for ensuring structural safety in tunnel engineering, yet conventional destructive techniques face limitations in efficiency and adaptability to complex underground environments. This study presents a novel wireless instrument based on the standing wave principle to enable remote, non-destructive length assessment. The system employs a master-slave architecture, where a handheld transmitter unit initiates measurements through robust 433 MHz wireless communication, optimized for signal penetration in obstructed spaces. The embedded measurement unit, integrated with anchor rods during installation, utilizes frequency-scanning technology to excite structural resonances. By analyzing standing wave characteristics, anchor length is derived from a calibrated frequency-length relationship. Power management adopts a standby-activation strategy to minimize energy consumption while maintaining operational readiness. Experimental validation confirms the system effectively measures anchor lengths with high precision and maintains reliable signal transmission through thick concrete barriers, demonstrating suitability for tunnel deployment. The non-destructive approach eliminates structural damage risks associated with traditional pull-out tests, while wireless operation enhances inspection efficiency in confined spaces. This work establishes a paradigm for embedded structural health monitoring in tunneling, offering significant improvements over existing methods in safety, cost-effectiveness, and scalability. The technology holds promise for broad applications in mining, underground infrastructure, and geotechnical engineering.

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