Experimental study on 3D internal penny‐shaped crack propagation in brittle materials under uniaxial compression

Abstract

Fractures are widely present in geomaterials of civil engineering and deep underground engineering. Given that geomaterials are usually brittle, the fractures can significantly affect the evaluation of underground engineering construction safety and the early warning of rock failure. However, the crack initiation and propagation in brittle materials under composite loading remain unknown so far. In this study, a three‐dimensional internal laser‐engraved cracking technique was applied to produce internal cracks without causing damage to the surfaces. The uniaxial compression tests were performed on a brittle material with internal cracks to investigate the propagation of these internal cracks at different dip angles under compression and shear. The test results show that the wing crack propagation mainly occurs in the specimen with an inclined internal crack, which is a mixed‐Mode I–II–III fracture; in contrast, Mode I fracture is present in the specimen with a vertical internal crack. The fractography characteristics of Mode III fracture display a lance‐like pattern. The fracture mechanism in the brittle material under compression is that the internal wing cracks propagate to the ends of the whole sample and cause the final failure. The initial deflection angle of the wing crack is determined by the participation ratio of stress intensity factors KII to KI at the tip of the internal crack.

Technogenic Reservoirs Resources of Mine Methane When Implementing the Circular Waste Management Concept

“…Unlike similar methods for assessing degassing productivity and volume of mine methane extraction, the authors' method allows us to quantify gas losses due to the failure of a local degassing network. The reasons may be different, but basically it is the failure of wells associated with the peculiarities of changes in the stress-strain state in the rock mass [68][69][70][71][72].…”

Numerical investigation on the influence of secondary flaw lengths on the mechanical characteristics and cracking behaviour of red sandstone containing orthogonal cross flaws

“…35,[50][51][52][53][54][55][56][57] Under three-dimensional conditions, crack propagation behaviour may exhibit different characteristics. [58][59][60][61][62][63][64][65] In our future work, we will study the influence of different degree of secondary flaw penetration and primary flaw angle on orthogonal cross-fractured rock through laboratory test and three-dimensional simulation.…”

“…In fact, the initiation and propagation of cracks are three‐dimensional behaviours, it is difficult to fully demonstrate the cracking behaviours from a two‐dimensional perspective 35,50–57 . Under three‐dimensional conditions, crack propagation behaviour may exhibit different characteristics 58–65 . In our future work, we will study the influence of different degree of secondary flaw penetration and primary flaw angle on orthogonal cross‐fractured rock through laboratory test and three‐dimensional simulation.…”