A Fiber Bragg Grating-Based Condition Monitoring and Early Damage Detection System for the Structural Safety of Underground Coal Mines Using the Internet of Things

Abstract

Accurate sensing is the key to structural health monitoring of underground coal mines while using fiber Bragg grating (FBG) sensors. However, the previously developed systems for structural monitoring of underground mines have been limited to monitoring without any capability of damage detection. Therefore, this study integrates a highly accurate FBG monitoring system and output-only data-driven approaches on an Internet of things (IoT)-based platform to develop a comprehensive mine structural safety system. This system relies on a Web 2.0 main server that runs data acquisition, data processing, and damage detection algorithms along with real-time information sharing at remote locations. This system was successfully implemented at the Hassan Kishore coal mine, situated in the Salt Range of Pakistan. Wavelength division multiplexing of the FBG strain sensors reliably captured the effects of dynamic and continuous coal excavation on the stability of mine roadway and access galleries. Principal component analysis, along with hierarchical clustering, was used to determine the damage indicator of the mine. The damage index was validated, showing the minimum value for 2% stiffness reduction. Thus, integration of FBG technology with the Internet can be effectively applied for early safety assessment of underground coal mines and information sharing in real time.

Hybrid Blockchain and Internet-of-Things Network for Underground Structure Health Monitoring

“…With reference to SHM, the working of smart contracts for autonomous decision making heavily relies on the threshold limit values. In this study, to check the applicability of the proposed blockchain-IoT network, as an example, the SHM data has been taken from our previous work [50] focusing on the utilization of FBG sensing to monitor an underground mine structure and determines the “damage index of mine (DIM)”. The sensed data is initially gathered at a gateway for pre-processing and filtering.…”

“…Being an index, DIM has no units. A detailed mathematical explanation for the calculation of DIM is out of the scope of this paper but can be found in our previous work [50]. The following are the major reasons to select this above-mentioned study to check the applicability of the proposed blockchain and IoT based distributed network.…”

“…The results of these simulations are based on the user’s perspective. Since we inherited the SHM of an underground coal mine from our previous work [50], we omit further SHM analysis here.…”

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

“…For the indicators of temperature and strain, Ye et al [5] described the study of tunnel safety monitoring during the construction stage based on quasi-distributed sensing technology of a limited number of fiber Bragg grating (FBG) sensors. Recently, references [6,7] reported some research advances in FBG-based sensors that combine the Internet of things or 3D printing techniques to detect damage or movement of underground structures. In addition to the conventional indicator, the study conducted in [8] indicates that some influencing factors, such as buried depth and operation age should also be collected when assessing the state of the tunnel.…”

Development of a Cloud Computing-Based Pier Type Port Structure Stability Evaluation Platform Using Fiber Bragg Grating Sensors

“…Furthermore, rapid growth of new technologies such as Internet of Things, wireless sensor network, and cloud computing has demonstrated the new capabilities and methods for a structural health monitoring in many researches. Structural health monitoring combined with automatic data processing for stability evaluation can be a promising direction for enhancing the structural safety of harbor structures [ 14 , 15 , 16 , 17 , 18 ]. Specifically, automatic data processing offers unique advantages in its use with harbor structure, which is difficult to monitor considering its size and depth.…”