A composite material model for investigation of micro-fracture mechanism of brittle rock subjected to uniaxial compression

来源期刊：中南大学学报(英文版)2001年第4期

论文作者：CHEN Feng SUN Zong-qi XU Ji-cheng ZHANG Jing-yi

文章页码：258 - 262

Key words：two-phase model; micro-fracture; rock; uniaxial compression

Abstract: A two-phase model of rock was proposed in order to investigate the mechanism of brittle fracture due to uniaxial compression, in which rock was considered to be a composite material consisting of hard grains and colloids. The stress state in colloid region near grains was calculated using Finite Element Method (FEM). The influence of the tensile stresses on the crack initiation and failure process of brittle rock subjected to uniaxial compression was investigated by numerical experiments. The FE results show that tensile stresses are induced easily in the neighboring area of hard grains with the maximum value near grain boundaries. The distribution of tensile stresses depends on the relative position of hard grains. The cracks initiated just near the boundary area of hard grains, whichwas governed bytensile stress. These results clearly reveal the micro-frac-ture mechanism of brittle rock loaded byuniaxial compression. It can be concluded that the failure mode of brittle rock under uniaxial compression is still tensile fracture from the point view of microstructure. However,since the wide colloid region is still under compressive stress state, further propagation of boundary cracks through this region obviously needs more external load, thus causing the uniaxial compressive strength of rock much higher than its tensile strength obtained via Brazilian (splitting) experiment.