Dynamic mechanical behaviors of interbedded marble subjected to multi-level uniaxial compressive cyclic loading conditions: An insight into fracture evolution analysis

• Published in: Engineering fracture mechanics Vol. 241; p. 107410
• Main Authors: Wang, Y., Hu, Y.Z., Gao, S.H.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01.01.2021; Elsevier BV
• Subjects: Amplitudes; Banded structure; Bridges; Coalescing; Computed tomography; Crack propagation; CT scanning; Cyclic loading; Cyclic loads; Damage accumulation; Damage evolution model; Damage patterns; Damping ratio; Elastic deformation; Evolution; Failure modes; Fatigue tests; Fracture evolution; Interbedded marble; Marble; Medical imaging; Mining engineering; Orientation; Pyrite; Scanning; Stiffness; Storage modulus; Cyclic loading; CT scanning; Fracture evolution; Damage evolution model; Interbedded marble
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/j.engfracmech.2020.107410

•Dynamic fracture evolution of marble is mainly impacted by interbed structure.•Rock stiffness degrades and damping improves with increasing interbed orientation.•A two-stage damage evolution model was proposed to describe the damage evolution.•Marble failure mode is rock structural dependent revealed by post-test CT images. Rocks in civil and mining engineering usually experience rather complex stress disturbance. Rock dynamic mechanical behaviors under constant stress amplitude condition have been widely studied. However, the rock fracture evolution characteristics subjected to multi-level cyclic loading conditions are not well understood. In this work, multi-level cyclic compressive loading experiments were performed on marble with interbed orientation of 0°, 30°, 60° and 90°. Anisotropic fracture evolution characteristics were revealed using dynamic stress strain descriptions and post-test CT scanning technique. Results show that rock fatigue deformation, strength, lifetime, dynamic elastic modulus and damping ratio are all impacted by rock structure. The interbed structure plays a dominant role in fracture evolution compared with natural fracture and pyrite band. Rock stiffness degrades and damping ratio increases with the increase of interbed orientation. In addition, a two-phase damage accumulation pattern was found for marble under multi-level cyclic loading condition. A damage evolution model was first established to model damage accumulation, the proposed model fits well to the experimental data. Moreover, post-test CT scanning reveals the internal crack coalescence pattern and failure mode is impacted by the interactions of interbeds, natural fracture and pyrite bands. The rock bridge structure in marble with 60° and 90° interbed orientation alters the crack propagation path. Although the crack pattern is relatively simple at rock bridge segment, much more energy is needed to drive crack propagation. The testing results are expected to improve the understanding of the influence of rock structure on fracture evolution when subjected to variable stress amplitude loading conditions.