ELASTIC COMPLIANCE FOR ROCK-LIKE MATERIALS WITH RANDOM CRACKS

Abstract

Elastic compliances for cracked materials like rocks and rock masses are theoretically formulated in terms of the generalized fabric tensor which has been introduced as an index measure to express explicity crack geometry. By means of uniaxial compression tests and supersonic wave velocity tests on gypsum plaster samples with random cracks, the formulation is proved to give a good approximation for describing the elastic response of cracked materials. The conclusions are summarized as follows : The principal axes of the fabric tensor of second-rank exactly coincide with the symmetry axes of the elastic compliance tensor of fourth-rank. The so-called self-consistent method is very useful to estimate the overall elastic moduli by taking into account effect of the elastic interaction among cracks. Since the supersonic wave velocity is closely related to the character of the fabric tensor, it can be expected that the field measurement of wave velocity is useful to estimate fabric tensor of in situ rock masses.