Summary
This novel method for reproducibly cutting joints in real rock will allow shearing of identical joints under varying stress paths. Shearing of such identical joints will greatly reduce the effect of sample variation and the need for scaling results.
Joint surfaces are cut with a diamond band saw through a computer controlled feed table. As constructed, the system is capable of cutting samples 20.3 cm (8 in) thick and 30.5 cm (12 in) long. The 6.35 mm (0.25 in) blade used in these tests allows cuts with a maximum radius of curvature of 1.6 cm (0.625 in). A maximum asperity inclination (i) of 28 degrees is possible with the largest samples. These characteristics, in general, are not inherent in the method but rather imposed by the current dimensions of the device.
The resulting surfaces, which have been produced in limestone, are analyzed in terms of surface finish at a micro scale, geometrical conformity to the desired surface, reproducibility of the surface and matchability of the two surfaces produced by one cut. These measures indicate a high level of accuracy which should produce repeatable test results when the joints are sheared under laboratory conditions.
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Hutson, R.W., Dowding, C.H. Computer controlled cutting of multiple identical joints in real rock. Rock Mech Rock Engng 20, 39–55 (1987). https://doi.org/10.1007/BF01019510
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DOI: https://doi.org/10.1007/BF01019510