Effect of Single Fissure Distribution on Mechanical Properties and Failure Characteristics of Composite Rock Samples

Abstract

Fissure distribution has a significant effect on mechanical properties and damage failure of layered rock mass with complex fissures. Based on the uniaxial compression test and the Digital Image Correlation (DIC) technique, influence of fissure location and fissure angle on the mechanical properties and failure of composite fissure rock sample composed of sandstone-like and martial-like rocks was analyzed. Results show that: (1) Composite fissure rock samples mechanical properties increase with the change of fissure location from sandstone, interface and marble and the increase of fissure angle. (2) When fissure is in marble, initial crack is easy to be far-field crack in sandstone, and surface spalling occurs in both sandstone and marble, but failure is more obvious in sandstone, prone to “H-shaped failure”. When fissure is at interface and sandstone, it is easy to produce wing crack and anti-wing crack at fissure tip of sandstone, “1γ shape failure” and “Y shape failure” are easy to occur respectively. At the same time, stress-strain levels “σ” and “ε” corresponding to initial crack generation at same fissure angle increase with the change of fissure position from sandstone, sandstone to marble and marble. (3) When the fissure location is same, the “σ” and “ε” of α = 90° are the largest, while the “σ” and “ε” of α = 0° and α = 45° are the smallest. “H-shaped failure” occurs when α = 0° and “Y-shaped failure” occurs when α = 90°.