Abstract
This study investigates the strain location and particle-scale contact properties of methane hydrate-bearing sediments with different cementing ratios λ through adopting discrete elements method (DEM). In this paper, a new numerical samples preparation technique that can reflect the real microstructure of methane hydrate-bearing sediments based on the nucleation and growth mechanism of methane hydrate is proposed, and a new hydrate bonding model that can consider the coupling effects of temperature and pore pressure is established. Then a series of biaxial shear tests in which flexible particle membrane boundaries are adopted to capture inhomogeneous deformation on the methane hydrate-bearing sediments with different cementing ratios are carried out to provide new insight on the formation and development of shear bands and the evolution of particulate-scale information inside hydrate-bearing sediments. The simulation results show that the increase of hydrate cementing ratios λ results in enhanced strength and volumetric dilatancy of hydrate-bearing sediments. The different hydrate cementing ratio creates several important differences about strain location modes of bond breakage, contact force chains, particles displacement and rotation, local void ratio, local coordination number, and local volumetric strain with the samples of lower cementing ratio exhibit two shear bands while the samples of higher cementing ratio exhibit single shear band. The main mechanical behaviors of hydrate-bearing sediments are controlled by three microscopic contacts (sand-sand contacts, sand-pore-filling hydrate contacts, and sand-cementation hydrate).
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call