Abstract:The loading tests were done on the brittle specimens with ordered multi-fissures which were made by pulling out the metallic shims at the early stage in the curing process under a uniaxial loading system with servo control. The numerical models of fissure bodies were established based on the strain-softening mechanism of brittle material with local damage characteristics under uniaxial compression. The failure mechanism and its influencing factors of brittle material with ordered multi-fissures were analyzed by comparing experiment results with numerical calculations. The results show that the failure characteristics of specimens are also influenced by the relative position of fissures besides the fissure inclination angle and its geometrical arrangement, and the influence degree has relationship with the effective shear stress on fissure surface. The larger the effective shear stress is, the more significant the influence is. The experimental results and numerical calculations show that a dominant failure surface exists in the specimen with ordered multi-fissures, which is coincident with the diagonal that has the same strike with fissures. The probability of micro-cracks appearing at the tips of fissures, which distribute in or are close to the dominant failure surface, is larger than the probability of the ones which are far from the dominant failure surface. Combined with the failure characteristics of specimens with ordered multi-fissures and yield situations of grid cells in numerical models, two kinds of simplified models are proposed to describe the spatial morphologies of closely-spaced fissures. Then, combined with this experimental result, the feasibility of simplified models is verified.

Key words: brittle material; ordered multi-fissures; failure mechanism; simplified model; dominant failure surface; strain-softening