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Lookup NU author(s): Professor Stefano Utili
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While methane hydrates (MHs) can be present in various forms in deep seabeds or permafrost regions, thispaper deals with MH-bearing sediments (MHBS) where the MH has formed bonds between sand grains. Abond model based on experimentally validated contact laws for cemented granules is introduced to describethe mechanical behavior of the MH bonds. The model parameters were derived from measured values oftemperature, water pressure and MH density. Bond width and thickness adopted for each bond of the MHBSwere selected based on the degree of MH saturation. The model was implemented into a 2D distinct elementmethod code. A series of numerical biaxial standard compression tests were carried out for various degreesof MH saturation. A comparison with available experimental data shows that the model can effectivelycapture the essential features of the mechanical behavior of MHBS for a wide range of levels of hydratesaturation under drained and undrained conditions. In addition, the analyses presented here shed light onthe following: (1) the relationship between level of cementation and debonding mechanisms taking placeat the microscopic level and the observed macro-mechanical behavior of MHBS and (2) the relationshipbetween spatial distribution of bond breakages and contact force chains with the observed strength, dilatancyand deformability of the samples.
Author(s): Jiang MJ, Zhu F, Liu F, Utili S
Publication type: Article
Publication status: Published
Journal: International Journal for Numerical and Analytical Methods in Geomechanics
Print publication date: 10/12/2014
Online publication date: 01/05/2014
Acceptance date: 03/03/2014
ISSN (print): 0363-9061
ISSN (electronic): 1096-9853
Publisher: John Wiley & Sons Ltd
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