Analysis of Influencing Factors on Brazilian Test Results Based on A Complex-shaped Grain Model for Brittle Rock

Abstract

Brazilian test is a commonly used laboratory method to measure the tensile strength of brittle rock, but there are also many controversies. In this paper, influencing factors including the Poisson’s ratio and the rock specimen thickness on Brazilian test results are investigated using PFC3D program based on a complex-shaped grain model which can capture all the characteristics of brittle rock in threedimensional environment. The relationship between the Poisson’s ratio and the tensile strength is observed through the comparison among three different models which presenting similar macro-properties except the Poisson’s ratio and the tensile strength. The study of specimen thickness effect indicates that the Brazilian test results significantly overestimate the real tensile strength of the specimens with relatively larger thickness. Through investigating the stress-strain curves and crack developing processes of the Brazilian test specimens, conclusions are made that the Brazilian tensile strength will increase with the specimen thickness due to the great loading increment.