Fatigue failure identification using deformation and energy rate for hole‐fissure contained granite under freeze–thaw and variable‐frequency–variable‐amplitude cyclic loads

• Published in: Fatigue & fracture of engineering materials & structures Vol. 45; no. 3; pp. 834 - 851
• Main Authors: Wang, Yu, Li, Juzhou, Zhu, Chun, Mao, Tianqiao
• Format: Journal Article
• Language: English
• Published: Oxford Wiley Subscription Services, Inc 01.03.2022
• Subjects: Amplitudes; Coalescing; Cyclic loads; Damage; Deformation; energy evolution; fatigue deformation; Fatigue failure; freeze–thaw; Granite; Laboratory tests; rock fatigue; Strain rate; Volumetric strain
• ISSN: 8756-758X; 1460-2695
• DOI: 10.1111/ffe.13639

This work conducted laboratory tests considering the coupled freeze–thaw (FT) and variable‐frequency–variable‐amplitude cyclic loads on granite containing two fissures and a circular hole. The analysis is dedicated to reveal the deformation and energy rate characteristics. Testing results show that increasing FT cycle and loading level both accelerate rock damage. The rock subjecting to high FT cycle behaves much larger damage rate in terms of volumetric strain and dissipated energy. The warning strength is defined according to the volumetric strain rate and dissipated energy rate which can early issue a warning than the crack damage stress point. In addition, the rock instability precursor is proposed by monitoring the incremental rate of the radial strain and volumetric strain; drastic damage occurs when the volumetric rate exceeds the radial rate. Three typical crack coalescence modes of double shear coalescence, single shear coalescence, and single tensile coalescence were revealed.