Journal Published Online: 30 November 2018
Volume 48, Issue 4

New Method of Monitoring Tunnel Feet-Lock Pipe (TFP) Mechanics Using Fiber Bragg Grating (FBG)

CODEN: JTEVAB

Abstract

Tunnel feet-lock pipe (TFP) is one of the most effective measures used to control tunnel settlement and is widely used in tunneling with soft ground or weak rock mass. Mechanical analysis is an important method to optimize TFP design and construction, and its results can be used to evaluate the structural stability of the tunnel. Although the traditional direct resistance method (DRM) can measure the mechanics of TFP, it is not suitable for harsh environments (humid environments, chemical etching, and electromagnetic field noise) or long-term monitoring. In this article, a method to measure the mechanics of TFP by using Fiber Bragg grating (FBG) is proposed. The strain and bending of TFP monitored by FBG is used to analyze the mechanics of TFP. In order to verify the feasibility and accuracy of the FBG method to measure the mechanics of TFP, an experimental scheme was designed to compare DRM and theoretical analysis. A supporting device and loading device were developed for the experimental scheme. Compared with the theoretical value, the error of strain and bending measured by FBG was stable within 5 με, the error of strain measured by DRM was approximately 15 με or even 20–30 με, and the error of bending measured by DRM was 10–15 με or even 25 με. Therefore, the precision of measuring the mechanics of TFP by using FBG is higher than by using DRM.

Author Information

Luo, Yanbin
School of Highway, Chang’an University, Xi’an, Shaanxi Province, China
Diao, Pengsheng
China State Construction International Investments (China) Ltd., Shenzhen, China
Chen, Jianxun
School of Highway, Chang’an University, Xi’an, Shaanxi Province, China
Li, Dong
Power China Road Bridge Group Co., Ltd., Beijing, China
Guo, Yalong
School of Highway, Chang’an University, Xi’an, Shaanxi Province, China
Qiao, Xiong
School of Civil Engineering, Lanzhou University of Technology, Gansu, China
Pages: 18
Price: $25.00
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Stock #: JTE20170364
ISSN: 0090-3973
DOI: 10.1520/JTE20170364