Detecting deformations in uncompacted strata by fiber Bragg grating sensors incorporated into GFRP

Chai, Jing; Liu, Jinxuan; Qiu, Bo; Li, Yi; Zhu, Liang; Wei, Shiming; Wang, Zhenping; Guang-wen, Zhang; Yang, Jianhua

doi:10.1016/j.tust.2010.06.009

Cited by 22 publications

(10 citation statements)

References 9 publications

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“…Any deformation of the grating caused by surface deformation or a change in temperature causes a shift in reflection at a Bragg wavelength which can be calibrated against the grating configuration. [9][10][11] FBG gauges have been successfully applied to monitor the structural health of civil infrastructure including mine networks, 12 roads 13 and tunnels. 14,15 However, contact gauges can only measure the strain accumulated around a small area and the results become less accurate at high strain rates.…”

Section: Introduction: Principles and Methodology Of Strain Measurementsmentioning

confidence: 99%

Near infrared spectroscopic measurement of strain in rocks

Butcher¹,

Gibson²,

Benson³

et al. 2019

Journal of Near Infrared Spectroscopy

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The measurement of strain is a fundamental and widely studied parameter in engineering, rock mechanics, construction and materials testing. Contact sensors often used in these fields require contact with the target surface throughout the duration of a strain event. Non-contact methods typically require that that the measurement surface is prepared and often coated prior to testing. This paper considers the potential application of near infrared spectroscopy as a non-contact technique for the measurement of strain on natural surfaces. Excellent correlation was found between surface measurements of visible-NIR spectra and longitudinal strain taken during indirect Brazilian Disc Test for samples of sandstone, marble and basalt.

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Section: Introduction: Principles and Methodology Of Strain Measurementsmentioning

confidence: 99%

Near infrared spectroscopic measurement of strain in rocks

Butcher¹,

Gibson²,

Benson³

et al. 2019

Journal of Near Infrared Spectroscopy

View full text Add to dashboard Cite

show abstract

“…Existing packaging methods include gluing FBG to the target and embedding with adhesives [22,23,24,25,26], packaging FBG in pipes or on plates [25,27,28,29,30], or encapsulating FBG into composites or layered structures [20,31,32,33,34]. For field geohazard monitoring, the installation works can be extremely tricky since the optical fibers can hardly be adhered on geomaterials.…”

Section: Development Of Fbg-based Geohazard Monitoring Systemsmentioning

confidence: 99%

“…In this aspect, experimental observations and theoretical calculations indicated that the FBG-based monitoring system was more sensitive to tensile strain than compressive tensile strain for rock layers under high loads [76]. Lately, Chai et al installed FBG sensors into a deep borehole to continuously measure the deformation of rock strata and shaft linings [33]. The monitoring data could help determine the health condition of shaft linings, thus ensuring the safety of coal mining.…”

Section: Current Status Of Applying Fbg Systems For Geohazard Monimentioning

confidence: 99%

FBG-Based Monitoring of Geohazards: Current Status and Trends

Zhu

Shi

Zhang

2017

Sensors

125

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In recent years, natural and anthropogenic geohazards have occured frequently all over the world, and field monitoring is becoming an increasingly important task to mitigate these risks. However, conventional geotechnical instrumentations for monitoring geohazards have a number of weaknesses, such as low accuracy, poor durability, and high sensitivity to environmental interferences. In this aspect, fiber Bragg grating (FBG), as a popular fiber optic sensing technology, has gained an explosive amount of attention. Based on this technology, quasi-distributed sensing systems have been established to perform real-time monitoring and early warning of landslides, debris flows, land subsidence, earth fissures and so on. In this paper, the recent research and development activities of applying FBG systems to monitor different types of geohazards, especially those triggered by human activities, are critically reviewed. The working principles of newly developed FBG sensors are briefly introduced, and their features are summarized. This is followed by a discussion of recent case studies and lessons learned, and some critical problems associated with field implementation of FBG-based monitoring systems. Finally the challenges and future trends in this research area are presented.

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“…Microdeformation monitoring, as a dynamic and realtime testing technology, can be an extremely important means for engineering disaster prevention and control [18][19][20][21][22]. Especially, in the field of deformation monitoring, Chai et al proposed a deformation monitoring method based on the fiber Bragg grating technique and established the strain transfer relationship between fiber Bragg grating and shaft lining [23][24][25][26]. eir proposed method can predict the actual stress-deformation and provide a basis for the prediction of shaft failure.…”

Section: Introductionmentioning

confidence: 99%

Deformation Monitoring and Stability Analysis of Shaft Lining in Weakly Cemented Stratum

Lyu

Wang

2018

Advances in Civil Engineering

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Shaft linings in thick weakly cemented stratum have the disadvantages of large deformation and repeated damage after repair. Considering the typical geologic characteristics and the failure characteristics of shaft linings, we establish a multilayer automatic deformation monitoring system in this paper, and the monitoring system can realize the real-time, continuous, and long-term dynamic monitoring on shaft linings. Based on the concrete strength failure criterion under biaxial compression and the analytical solution for spatially axisymmetric problem of thick-wall cylinders, the damage limit of the shaft lining in Xieqiao coal mine is obtained. Then, we choose three sections as the test area according to the typical damage forms of shaft linings to carry out the monitoring scheme on the auxiliary shaft in Xieqiao coal mine. The monitoring results show that the extreme value of the shaft lining deformation is 2.369 mm. And the shaft lining located in the border between the floor aquifer and the bedrock generates the most severe deformation, which is about 89.4% of the deformation limit. The shaft lining deformation increment fluctuates in certain range, which belongs to elastic deformation. Finally, we inverse the stress state according to the deformation value of the shaft lining, and the obtained additional stress is found to be lower than the ultimate compressive strength. Long-term project practice confirms that the deformation monitoring results can reflect the real stress condition of the shaft lining and that the monitoring system can realize the real-time dynamic evaluation for the status of the shaft lining.

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Detecting deformations in uncompacted strata by fiber Bragg grating sensors incorporated into GFRP

Cited by 22 publications

References 9 publications

Near infrared spectroscopic measurement of strain in rocks

Near infrared spectroscopic measurement of strain in rocks

FBG-Based Monitoring of Geohazards: Current Status and Trends

Deformation Monitoring and Stability Analysis of Shaft Lining in Weakly Cemented Stratum

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