On the Measurement of Anisotropic Elastic Constants of Rock-Like Materials by Uni-Axial Compression Test

In the field of rock mechanics, it is well recognized that the elastic anisotropy is one of the important mechanical properties of mineral, rock, and rock mass. But, because of troublesomeness of the measurement, anisotropic elastic constants of these materials are not measured so frequently. Particularly the constants which give the relationship between shear stress and strain are rarely measured. The reason is that the preparation of torsion test pieces is relatively difficult, although the torsion test is usualy thought to be essential for obtaining these anisotropic constants.In this paper, it is shown that the all 21 elastic constants can be calculated using the transformation law of the co-ordinate of elastic constants, from the test results of uni-axial compression in which the axes of test pieces are varied to the principal axes of anisotropy.As an example, the experimental results and the calculated compliances of calcite (trigonal) are shown. The preciseness of the measurement is also discussed.