A.J. Hyett

A.J. Hyett
Yieldpoint Inc

About

27
Publications
11,157
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636
Citations
Introduction
A.J. Hyett is the CEO of YieldPoint Inc, a worldwide supplier of geotechnical instruments based in Kingston, Ontario, Canada. YieldPoint designs, manufactures and sells instrumentation, telemetry, data aggregation, and data management solutions.
Skills and Expertise

Publications

Publications (27)
Article
Full-text available
A recent research campaign at a Canadian nickel-copper mine involved instrumenting a hard rock sill drift pillar with an array of multi-point rod extensometers, distributed optical fiber strain sensors, and borehole pressure cells. The instrumentation spanned across a 15.24 m lengthwise segment of the relatively massive granitic pillar that was sit...
Conference Paper
Full-text available
A monitoring program employed to measure the support performance of spiles in a recent Canadian tunnel project is presented. Of novelty in this research is the use of a distributed optical strain sensing technique to measure the load distribution of individual spile support members at a spatial resolution of 0.65mm. The distinct challenges and tech...
Article
Full-text available
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 millimeters along the length of a...
Article
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...
Article
Full-text available
In addressing limitations of conventional ground support measurement, a novel optical strain sensing technique is presented that is capable of measuring strain at increments as low as 0.65 mm along the entirety of an optical sensor affixed to a support element. The technique considers monitoring three sensing lengths along the profile of a fully gr...
Conference Paper
Full-text available
Capturing the three-dimensional load distribution along fully grouted bolts has been inherently difficult to accomplish with conventional strain techniques. A general lack of spatial resolution of strain measurements along instrumented bolts has resulted in localized loading conditions, such as shear and bending, being misinterpreted and, perhaps,...
Article
Full-text available
Primary roof support represents the first line of defence against rock-related falls of ground in underground mines, and improper utilization or misunderstanding of the applicability and behaviour of primary support can be costly from a safety standpoint. This is a major concern for underground mines, as roof support is the single most costly expen...
Article
The mechanism of bond failure in cables of conventional and of modified geometry has been investigated through laboratory tests under constant confining pressure. The axial load and radial dilatation due to axial cable displacement were determined from the tests. Bond failure in conventional cables is 'cable untwisting', whereas 'grout shearing' is...
Conference Paper
Full-text available
Due to the inherent strengths and weaknesses of existing cable bolt design tools it is necessary, to optimise the ultimate desgin, that a multifaceted approach be followed. This multifaceted methodology should be tailored to suite the specific engineering problem at hand. Ground conditions at each of the two field trials at Hudson Bay Mining and Sm...
Conference Paper
Full-text available
Cable bolts are widely used as a principal means of support. The monitoring of the performance of reinforcement is critical in improving and optimising reinforcement designs. This paper presents case studies where Stretch Measurement to Assess Reinforcement Technology (SMART) instrumentation was used in conjunction with other observational, analyti...
Conference Paper
Full-text available
Cable bolts are widely used as a principal means of support. The monitoring of the performance of reinforcement is critical in improving and optimising reinforcement designs. This paper presents a case study where Stretch Measurement to Assess Reinforcement Technology (SMART) instrumentation was used in conjunction other observational, analytical,...
Article
Full-text available
Explanation for the widely reported observation that fully grouted reinforcement is more effective in hard rock that behaves as a discontinuum than in soft rock is presented. Analytical solutions are presented for the distribution of displacement and load along an untensioned fully grouted elastic bolt, of specified bond stiffness, which is activat...
Article
Full-text available
A series of pull tests were performed using fully-grouted seven-wire strand cable, in which the confining pressure at the outside of the cement annulus was maintained constant using a modified Hoek cell. The bond strength was shown to increase with confining pressure. The associated radial displacements at the outside of the cement annulus were mea...
Article
A laboratory and field research programme was conducted to investigate the major factors influencing the bond capacity of grouted cable bolts. All tests were conducted on standard ″ (15.9 mm) 7-strand cable groted using type 10 Portland cement pastes. The results indicate that cable bolt capacity most critically depends on: 1.(i) the cement propert...
Article
This technical note describes a proven experimental procedure designed to eliminate rotation during cable pull tests. In situ cable pull tests measure the short term strength of a short section of cable bolt installed under representative field conditions. Criteria are given for selecting a suitable test site and the equipment needed for the test i...
Article
A laboratory and field research program was conducted to investigate the major factors influencing bond capacity of grouted cable bolts. The results indicate that cable bolt capacity most critically depends on the grout uniaxial compressive strength (UCS), the radial confinement, and the embedment length. In the laboratory 'split-pipe' tests were c...
Article
The Tutt Head thrust zone is the tip of a forward propagating lateral ramp which links two levels of detachment within the Langland-Mumbles Anticline. An early pressure-solution accommodated cataclastic phase of deformation is partially overprinted by later plastic deformation involving dislocation glide, dislocation climb and grain-boundary slidin...

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