Journal Published Online: 31 August 2005
Volume 28, Issue 6

Triaxial Ultra-Small Strain Measurements Using Laser Interferometry



This paper describes a prototype device for ultra-small strain triaxial stiffness measurement, using laser-optic interferometry, and based upon the Fabry-Perot principle. The results of a test on an intact specimen of weak rock are presented, and comparisons made between measurements using this device and a submersible LVDT system. The displacement resolution of the interferometer was 0.0006 μm and the strain resolution 8 × 10−7%. It is shown that the measurement uncertainty of the instrument was low compared with the magnitude of the displacements measured and in addition it was sufficiently accurate to detect the linear stress-strain behavior of a weak rock.

Author Information

Heymann, G
University of Pretoria, Pretoria, South Africa
Clayton, CRI
University of Southampton, Southampton, UK
Reed, GT
University of Surrey, Buildford, UK
Pages: 9
Price: $25.00
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Stock #: GTJ10406
ISSN: 0149-6115
DOI: 10.1520/GTJ10406