关键词: 裂隙扩展;裂隙贯通;应变集中;双轴加载

Abstract: The effects of flaw angle and rock bridge ligament angle on cracking behavior were investigated.The prismatic cement specimens containing two flaws were tested under biaxial compression.The relationships of stress-strain curve with cracking process are researched,and the influences of strain concentration at flaw tip on crack development are studied through the strain gauge.The experimental results show that the flaw parameters (flaw angle and ligament angle) have notable influence on crack development and coalescence process of the specimen containing two flaws.Seven patterns of crack coalescences (T1 and T2;S1 and S2;and TS1,TS2 and TS3) and two failure patterns of crack coalescences (shear crack failure;wing-shear crack failure) are observed in the experiments.In addition,the crack coalescence varies from the S-mode to the TS-mode and then to the T-mode with the increase of ligament angle.The stress-strain curves of the specimens are closely related to the crack propagation.Tensile strain concentration may induce wing cracks,while compressive strain concentration will induce shear cracks.

Key words: crack propagation;crack coalescence;strain concentration;biaxial compression