Influence of structural plane angle and roughness on Brazilian characteristics of composite disc specimens

Abstract

In this paper, Brazilian test was performed on disk samples of analogue materials with defined structural planes. The surface strain evolution process of the disk samples during loading was analyzed via digital image correlation. The damage evolution process was explored from a microscopic perspective by combining discrete element numerical simulation technology. The criterion of the failure mode of the disc specimen in the split state was theoretically deduced. The influence of structural surface roughness and loading inclination angle on the stress state at the center of the specimen was explored. The results showed that the failure modes of the samples could be divided into three typical modes as matrix failure, structural plane failure and combination failure. The rough structural plane improves the failure strength of the specimen by limiting its lateral deformation, and the degree of improvement weakens continuously with the increase of the inclination angle of the structural plane. As the inclination angle of the structural plane increases, the main type of microcracks in the structural plane changes from shear microcracks to tensile microcracks. This study contributes to a better understanding of macro- and meso-failure characteristics of rock masses with structural planes under a splitting state.

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Central South University