Identification of Ground Intrusion in Underground Structures Based on Distributed Structural Vibration Detected by Ultra-Weak FBG Sensing Technology

Weibing Gan; Sheng Li; Zhengying Li; Lizhi Sun

doi:10.3390/s19092160

Identification of Ground Intrusion in Underground Structures Based on Distributed Structural Vibration Detected by Ultra-Weak FBG Sensing Technology

Sensors ◽

10.3390/s19092160 ◽

2019 ◽

Vol 19 (9) ◽

pp. 2160 ◽

Cited By ~ 9

Author(s):

Weibing Gan ◽

Sheng Li ◽

Zhengying Li ◽

Lizhi Sun

Keyword(s):

Fiber Optic ◽

Structural Vibration ◽

Underground Structures ◽

Subway Tunnel ◽

Tunnel Wall ◽

Sensing Technology ◽

Detection Approach ◽

Vibration Responses ◽

Subway Tunnels ◽

Weak Fbg

It is challenging for engineers to timely identify illegal ground intrusions in underground systems such as subways. In order to prevent the catastrophic collapse of subway tunnels from intrusion events, this paper investigated the capability of detecting the ground intrusion of underground structures based on dynamic measurement of distributed fiber optic sensing. For an actual subway tunnel monitored by the ultra-weak fiber optic Bragg grating (FBG) sensing fiber with a spatial resolution of five meters, a simulated experiment of the ground intrusion along the selected path was designed and implemented, in which a hydraulic excavator was chosen to exert intrusion perturbations with different strengths and modes at five selected intrusion sites. For each intrusion place, the distributed vibration responses of sensing fibers mounted on the tunnel wall and the track bed were detected to identify the occurrence and characteristics of the intrusion event simulated by the discrete and continuous pulses of the excavator under two loading postures. By checking the on-site records of critical moments in the intrusion process, the proposed detection approach based on distributed structural vibration responses for the ground intrusion can detect the occurrence of intrusion events, locate the intrusion ground area, and distinguish intrusion strength and typical perturbation modes.

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Combining SDAE Network with Improved DTW Algorithm for Similarity Measure of Ultra-Weak FBG Vibration Responses in Underground Structures

Sensors ◽

10.3390/s20082179 ◽

2020 ◽

Vol 20 (8) ◽

pp. 2179

Author(s):

Sheng Li ◽

Xiang Zuo ◽

Zhengying Li ◽

Honghai Wang ◽

Lizhi Sun

Keyword(s):

Similarity Measure ◽

Nearest Neighbor ◽

Distance Measure ◽

Integrated Approach ◽

Structural Vibration ◽

Distributed Monitoring ◽

Underground Structures ◽

Long Distance ◽

Vibration Responses ◽

Weak Fbg

Quantifying structural status and locating structural anomalies are critical to tracking and safeguarding the safety of long-distance underground structures. Given the dynamic and distributed monitoring capabilities of an ultra-weak fiber Bragg grating (FBG) array, this paper proposes a method combining the stacked denoising autoencoder (SDAE) network and the improved dynamic time wrapping (DTW) algorithm to quantify the similarity of vibration responses. To obtain the dimensionality reduction features that were conducive to distance measurement, the silhouette coefficient was adopted to evaluate the training efficacy of the SDAE network under different hyperparameter settings. To measure the distance based on the improved DTW algorithm, the one nearest neighbor (1-NN) classifier was utilized to search the best constraint bandwidth. Moreover, the study proposed that the performance of different distance metrics used to quantify similarity can be evaluated through the 1-NN classifier. Based on two one-dimensional time-series datasets from the University of California, Riverside (UCR) archives, the detailed implementation process for similarity measure was illustrated. In terms of feature extraction and distance measure of UCR datasets, the proposed integrated approach of similarity measure showed improved performance over other existing algorithms. Finally, the field-vibration responses of the track bed in the subway detected by the ultra-weak FBG array were collected to determine the similarity characteristics of structural vibration among different monitoring zones. The quantitative results indicated that the proposed method can effectively quantify and distinguish the vibration similarity related to the physical location of structures.

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A Novel Monitoring Approach for Train Tracking and Incursion Detection in Underground Structures Based on Ultra-Weak FBG Sensing Array

Sensors ◽

10.3390/s19122666 ◽

2019 ◽

Vol 19 (12) ◽

pp. 2666 ◽

Cited By ~ 3

Author(s):

Qiuming Nan ◽

Sheng Li ◽

Yiqiang Yao ◽

Zhengying Li ◽

Honghai Wang ◽

...

Keyword(s):

Safety Management ◽

High Sensitivity ◽

Underground Structures ◽

Long Distance ◽

Sensing Technology ◽

Frequency Domains ◽

Envelope Processing ◽

Critical Issues ◽

Vibration Responses ◽

Subway System

Tracking operating trains and identifying illegal intruders are two important and critical issues in subway safety management. One challenge is to find a reliable methodology that would enable these two needs to be addressed with high sensitivity and spatial resolution over a long-distance range. This paper proposes a novel monitoring approach based on distributed vibration, which is suitable for both train tracking and incursion detection. For an actual subway system, ultra-weak fiber Bragg grating (FBG) sensing technology was applied to collect the distributed vibration responses from moving trains and intruders. The monitoring data from the subway operation stage were directly utilized to evaluate the feasibility of the proposed method for tracking trains. Moreover, a field simulation experiment was performed to validate the possibility of detecting human intrusion. The results showed that the diagonal signal pattern in the distributed vibration response can be used to reveal the location and speed of the moving loads (e.g., train and intruders). Other train parameters, such as length and the number of compartments, can also be obtained from the vibration responses through cross-correlation and envelope processing. Experimental results in the time and frequency domains within the selected intrusion range indicated that the proposed method can distinguish designed intrusion cases in terms of strength and mode.

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Monitoring and analysis of the subway tunnel wall temperature and surrounding rock/soil heat absorption ratio

Building and Environment ◽

10.1016/j.buildenv.2021.107657 ◽

2021 ◽

Vol 194 ◽

pp. 107657

Author(s):

Peng Zhao ◽

Xiaozhao Li ◽

Jiajun Liu ◽

Donghai Zhang ◽

Hengjun Qiao

Keyword(s):

Wall Temperature ◽

Surrounding Rock ◽

Heat Absorption ◽

Subway Tunnel ◽

Tunnel Wall ◽

Absorption Ratio

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Application of fiber optic sensing technology in anchor monitoring

10.1117/12.385550 ◽

2000 ◽

Author(s):

Lei Liang ◽

Desheng Jiang ◽

Dongya Sun

Keyword(s):

Fiber Optic ◽

Sensing Technology ◽

Fiber Optic Sensing

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Dynamic Study of a Rooftop Vertical Axis Wind Turbine Tower Based on an Automated Vibration Data Processing Algorithm

Energies ◽

10.3390/en11113135 ◽

2018 ◽

Vol 11 (11) ◽

pp. 3135 ◽

Cited By ~ 5

Author(s):

Ying Wang ◽

Wensheng Lu ◽

Kaoshan Dai ◽

Miaomiao Yuan ◽

Shen-En Chen

Keyword(s):

Wind Turbine ◽

Vertical Axis ◽

Dynamic Responses ◽

Ambient Vibration ◽

Structural Vibration ◽

Vertical Axis Wind Turbine ◽

Mode Identification ◽

Stochastic Subspace Identification ◽

Vibration Data ◽

Vibration Responses

When constructed on tall building rooftops, the vertical axis wind turbine (VAWT) has the potential of power generation in highly urbanized areas. In this paper, the ambient dynamic responses of a rooftop VAWT were investigated. The dynamic analysis was based on ambient measurements of the structural vibration of the VAWT (including the supporting structure), which resides on the top of a 24-story building. To help process the ambient vibration data, an automated algorithm based on stochastic subspace identification (SSI) with a fast clustering procedure was developed. The algorithm was applied to the vibration data for mode identification, and the results indicate interesting modal responses that may be affected by the building vibration, which have significant implications for the condition monitoring strategy for the VAWT. The environmental effects on the ambient vibration data were also investigated. It was found that the blade rotation speed contributes the most to the vibration responses.

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Ultra-weak FBG array for fiber-optic sensing applications

2018 23rd Opto-Electronics and Communications Conference (OECC) ◽

10.1109/oecc.2018.8729920 ◽

2018 ◽

Author(s):

Cheng Cheng ◽

Jianguan Tang ◽

Minghong Yang

Keyword(s):

Fiber Optic ◽

Sensing Applications ◽

Fiber Optic Sensing ◽

Weak Fbg

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Surface intrusion event identification for subway tunnels using ultra-weak FBG array based fiber sensing

Optics Express ◽

10.1364/oe.387317 ◽

2020 ◽

Vol 28 (5) ◽

pp. 6794 ◽

Cited By ~ 3

Author(s):

Liping Xin ◽

Zhengying Li ◽

Xin Gui ◽

Xuelei Fu ◽

Minlang Fan ◽

...

Keyword(s):

Event Identification ◽

Fiber Sensing ◽

Subway Tunnels ◽

Weak Fbg

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Fiber optic distributed sensing technology for real-time monitoring water jet tests: Implications for wellbore integrity diagnostics

Journal of Natural Gas Science and Engineering ◽

10.1016/j.jngse.2018.08.005 ◽

2018 ◽

Vol 58 ◽

pp. 241-250 ◽

Cited By ~ 5

Author(s):

Yankun Sun ◽

Ziqiu Xue ◽

Tsutomu Hashimoto

Keyword(s):

Real Time ◽

Fiber Optic ◽

Water Jet ◽

Distributed Sensing ◽

Real Time Monitoring ◽

Wellbore Integrity ◽

Sensing Technology

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Detection of Leak-Induced Pipeline Vibrations Using Fiber—Optic Distributed Acoustic Sensing

Sensors ◽

10.3390/s18092841 ◽

2018 ◽

Vol 18 (9) ◽

pp. 2841 ◽

Cited By ~ 14

Author(s):

Pavol Stajanca ◽

Sebastian Chruscicki ◽

Tobias Homann ◽

Stefan Seifert ◽

Dirk Schmidt ◽

...

Keyword(s):

Fiber Optic ◽

Broadband Noise ◽

Gas Pipeline ◽

Accelerometer Data ◽

Acoustic Sensing ◽

System Sensitivity ◽

Spectral Integration ◽

Detection Approach ◽

Distributed Acoustic Sensing ◽

Pipeline Vibration

In the presented work, the potential of fiber-optic distributed acoustic sensing (DAS) for detection of small gas pipeline leaks (<1%) is investigated. Helical wrapping of the sensing fiber directly around the pipeline is used to increase the system sensitivity for detection of weak leak-induced vibrations. DAS measurements are supplemented with reference accelerometer data to facilitate analysis and interpretation of recorded vibration signals. The results reveal that a DAS system using direct fiber application approach is capable of detecting pipeline natural vibrations excited by the broadband noise generated by the leaking medium. In the performed experiment, pipeline vibration modes with acceleration magnitudes down to single μg were detected. Simple leak detection approach based on spectral integration of time-averaged DAS signals in frequency domain was proposed. Potential benefits and limitations of the presented monitoring approach were discussed with respect to its practical applicability. We demonstrated that the approached is potentially capable of detection and localization of gas pipeline leaks with leak rates down to 0.1% of the pipeline flow volume and might be of interest for monitoring of short- and medium-length gas pipelines.

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