Abstract
A borehole deformation sensor for long-term stress monitoring in coal mine rock based on optical fiber Bragg gratings (FBGs) is presented. The sensor converts borehole deformation into optical fiber strain by using four rings. For each ring, two FBGs are bonded with the ring to measure the borehole deformation, and a reference FBG free from mechanical load is introduced to remove the temperature effect. Two simple checks on the test data can be performed to improve the test accuracy. Laboratory and field tests were conducted to validate the accuracy and long-term performance of the sensor. The results show that the sensor is capable of measuring stress in rock with good accuracy, and it performs well over a long period of time in coal mines. The developed sensor provides an approach for the long-term monitoring of stress changes in coal mine rock.
Highlights
Stress-induced instability is one of several major concerns for the safe construction and operation of coal mines
The measurement of in situ stresses is important in the design of coal mines, and monitoring of how stress changes with time is vital when assessing the long-term performance of coal mines
The main objective of this study is to develop a fiber Bragg gratings (FBGs) borehole deformation sensor for both the determination of in situ stresses and the long-term monitoring of stress changes in coal mine rock
Summary
Stress-induced instability is one of several major concerns for the safe construction and operation of coal mines. It is of significance to develop a sensor for both the determination of in situ stress and the long-term monitoring of stress changes in coal mine rock. Because the borehole deformation gauge can be calibrated to ensure its accuracy, it is regarded as one of the most reliable and accurate sensors for stress determination. For these test techniques and sensors, Sjoberg et al [11] introduced in detail the methods of data analysis and stress calculation. Most of the existing sensors are used for the determination of the in situ stress, and they do not allow the continuous observation of stress changes or do not perform well in the long-term monitoring of stress changes [13], especially in harsh environments like coal mines
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
