Strain and creep measurements on rocks by halographic interferometry
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A technique is described for measuring strains in rock deformation experiments by means of holographic interferometry. The method allows the entire surface displacement field of the sample to be mapped to within one-tenth the wavelength of light. Several illustrative experiments show that inhomogeneous strain, in particular bending and torsion, is commonly present in uniaxial compression experiments, and that some of this strain can be caused by the testing machine. In a creep experiment in uniaxia compression, a concentration of dilatancy was observed very early in the experiment that was spatially related to the location of the ultimate failure plane.
KeywordsTesting Machine Displacement Field Uniaxial Compression Entire Surface Surface Displacement
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