Crack coalescence and failure patterns in brittle rock-like specimens with pre-existing fissures under uniaxial loading: experimental studies

摘要

In practical engineering, the joints or fissures with similar characteristics are commonly found in natural rocks, they decrease the mechanics properties of the rock mass and also can be seen as a source of initiation of new discontinuities. The previous studies (experimental or numerical) has promoted the understanding of coalescence patterns or failure process obtained from brittle specimens which contain single, two or three fissures. However, the failure characteristics of multi-fissure specimens has not been studied comprehensively. In this paper, the crack coalescence pattern and failure mode of the rock-like materials with multi-fissures have been explored. Based on the experiment results, under unaxial compression, we found that the coalescence modes between fissures can be generally classified into three categories: T/S/M pattern. Moreover, due to the difference of inclination angle and fissure numbers, the specimens present different failure mode. Careful examination all of specimens, the failure mode can be classified into 4 categories: Mix failure model(shear+splitting), Shear failure, Stepped path, Intact failure.