New technology for measuring the in situ performance of rock bolts

Spearing, A.J.S.; Hyett, A. J.; Kostecki, T.; Gadde, Murali M.

doi:10.1016/j.ijrmms.2012.07.027

Cited by 27 publications

(8 citation statements)

References 9 publications

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“…Most of the experiments conducted until 2013 used two opposite slots to place short-length resistive strain gauges. Spearing et al (2013) pointed out the ineffectiveness of instrumented rock bolts using short-length resistive strain gauges in which no more than 10% of the bolt length was monitored. Increasing the number of strain gauges would also raise the costs making it unaffordable since the strain gauges are expensive.…”

Section: Historical Instrumented Rockbolt Trialsmentioning

confidence: 99%

The Design of Improved Optical Fibre Instrumented Rockbolts

et al. 2020

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Developing an improved understanding of the interaction between the immediate roof and the rockbolts is fundamental in obtaining an effective roof support system. Effective instrumentation along the full length of fully grouted rock bolts would provide the required understanding, which in turn could improve the rock related safety in the underground mines. The rock bolt sensing technology has rapidly developed in the last decade, where the instrumentation has changed from short electrical strain gauges to optical strain and shape sensing using more than 2 slots (which used to be the standard). In addition, the instrumentation has been increased from two orthogonal slots to three or four. With these recent advances of the technologies, there lies a challenge in analysing and understanding the new type of data and in effectively adopting the new technology into the underground mines. This paper deals with the challenges of instrumenting rock bolts with fibre optics and presents techniques for improving the existing technology. Furthermore, it includes a prototype design for an effective implementation of this technology to better suit the harsh underground environment.

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Section: Historical Instrumented Rockbolt Trialsmentioning

confidence: 99%

The Design of Improved Optical Fibre Instrumented Rockbolts

et al. 2020

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“…Spearing et al [ 40 ] tried a similar technique, replacing the short base-length resistive strain gauges with long base-length, from 200 mm to 500 mm, inductive strain gauges. Thus, owing that, the measurement results have been provided by “measurement zones” rather than “measurement points” as it was before.…”

Section: Introductionmentioning

confidence: 99%

Prototype of Instrumented Rock Bolt for Continuous Monitoring of Roof Fall Hazard in Deep Underground Mines

Fuławka

Pytel

Szumny

et al. 2022

Sensors

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Roof falls are currently one of the most dangerous threats associated with underground mining at great depth. Every occurrence of such an event poses a significant risk to the mining crew and disturbs the continuity of the mining process, which clearly affects the economy of the exploitation process. The development of a reliable monitoring system may significantly reduce the impact of eventual roof failure and will have a positive effect on the sustainability of the extraction process. Within this research study, a prototype of an instrumented rock bolt developed for continuous stress measurement is presented. The procedure of a 4-groove multilevel instrumented rock bolt is described and the calibration process is shown. Then, preliminary results of long-term in situ monitoring are presented. Based on the continuous monitoring of stress distribution within immediate roof strata, it was concluded that the developed instrumented rock bolt provides reliable results and is a very useful device, ensuring the possibility of early warning for miners about increasing roof fall risk.

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“…Examples include electrical-resistive strain gauges (e.g. , Farmer 1975;Serbousek and Signer 1987), load cells (e.g., Rodger et al 1996;Mitri 2011), long base-length induction gauges and displacement transducers (e.g., Choquet and Miller 1988;Spearing et al 2013), and inclinometers (e.g., Volkmann 2003). Using these sensing techniques, the support member under study is effectively discretized into a number of discrete (or individual) measurement points or zones depending on the gauge length of the chosen sensor (see Fig.…”

Section: Introductionmentioning

confidence: 99%

The application of distributed optical strain sensing to measure the strain distribution of ground support members

Forbes

Vlachopoulos

Hyett³

2018

FACETS

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A distributed optical strain-sensing technique is presented as a solution for measuring the strain distribution along ground support members used in tunnelling and mining works. The technique employs a Rayleigh optical frequency domain reflectometry technology, which measures strain at a spatial resolution of 0.65 mm along the length of a standard optical fiber. A rationale for selecting this technology as a potential monitoring technique for ground support elements over alternative commercially available technologies is discussed. The development of a technique to couple optical fiber sensors with rock bolt, umbrella arch, and cable bolt support members is also demonstrated. A robust laboratory investigation of such optically instrumented support members demonstrated the capability of the technique to capture the expected in situ support behaviour in the form of coaxial, lateral, and shear loading arrangements as would be anticipated in the field. Moreover, the microscale data obtained by this optical sensing technique are shown to provide unprecedented insight into the local/micro-scale geomechanistic complexities associated with the bearing capacity of ground support members, especially when compared with data obtained by discrete strain-sensing technologies.Key words: distributed optical strain sensing, ground support, rock bolt, cable bolt, strain measurement, strain profile OPEN ACCESSCitation: Forbes B, Vlachopoulos N, and Hyett AJ. 2018. The application of distributed optical strain sensing to measure the strain distribution of ground support members. FACETS 3: 195-226.

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New technology for measuring the in situ performance of rock bolts

Cited by 27 publications

References 9 publications

The Design of Improved Optical Fibre Instrumented Rockbolts

The Design of Improved Optical Fibre Instrumented Rockbolts

Prototype of Instrumented Rock Bolt for Continuous Monitoring of Roof Fall Hazard in Deep Underground Mines

The application of distributed optical strain sensing to measure the strain distribution of ground support members

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