An experimental study of the elasticity of mylonite rock with random cracks

Abstract An elastic compliance tensor for discontinuous rock masses is formulated by treating each crack with an elastic equivalent, which consists of parallel plates connected by two springs. The complex geometry of cracks, which is commonly observed in actual rock masses, is explicitly taken into account in the formulation, by means of a crack tensor. Uniaxial compression tests on eight mylonite samples were carried out to verify the utility of the elastic compliance tensor with the following conclusions: the elasticity of the samples, which have completely different appearances in terms of their crack geometry, can be compared in a general manner by the help of the crack tensor concept. The spring model is an acceptable idealization to simulate the elasticity of the mylonite samples with random cracks if the hysteresis characteristic of springs are properly considered. Experimental results on Young's moduli of the mylonite samples are in accord with the theoretical prediction, although the strength cannot be easily related to the overall characteristics of crack geometry.

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