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Fracture evolution in artificial bedded rocks containing a structural flaw under uniaxial compression

Wang, Ding-Jian, Tang, Huiming, Elsworth, Derek, Wang, Chaoyi
Engineering geology 2019 v.250 pp. 130-141
cracking, engineering, isotropy, prediction, rocks, shear stress
The Observation and prediction of crack propagation are important in understanding rock behavior in engineering practice. Previous studies have focused on homogeneous and isotropic rocks, but the influence of bedding planes on rock fracture is sparingly documented. In this study, we investigate the fracturing response in uniaxial compression of artificial bedded rocks containing variable-inclination bedding planes and single structural flaws. The recorded stress-strain data and captured cracking patterns are examined together. Nine separate crack types are identified in which bedding-plane sliding and splitting are potentially new. The presence of bedding planes plays a decisive role in crack propagation. With a steepening of the bedding plane, tensile cracks initiating from the structural flaw are better able to propagate along bedding planes, and the accumulative length of bedding fractures accordingly increases. Failure transforms from a purely tensile mode to a bedding sliding mode and subsequently to a bedding splitting mode as the bedding inclination increases. Compared to pro-dip flaw tests, the fracturing of bedding planes is triggered by both the tensile and shear stress with more far-field tensile cracks initiating from bedding planes in the specimens containing anti-dip flaws. Finally, the results are applied to predict the failure mode and fracture evolution in bedded rock slopes.