Shear strength degradation of gas hydrate-bearing sediment due to partial hydrate dissociation

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外文摘要：Extraction of methane hydrate from subseafloor reservoir may potentially trigger seabed slides and induce subsidence.To address the problems,it is crucial to properly characterize the phase equilibrium condition of pore hydrate and the shear strength of the soil.As one of the key constitutive components,the phase equilibrium condition enforces a constraint over pore gas pressure,temperature and unhy-drated water content.Such a constraint,however,has been traditionally ignored in analyzing the me-chanical behavior of hydrate-bearing soil.In this paper,a series of stepwise hydrate dissociation tests was performed,and the phase equilibrium condition of pore hydrate was determined,providing an effective way to evaluate the unhydrated water content during hydrate dissociation.Meanwhile,a series of direct shear tests was also conducted to explore the shear strength characteristics of the soil.It is shown that the shear strength of the hydrate-bearing soil can be significantly influenced by pore gas pressure,unhydrated water content,hydrate saturation and several other factors.In particular,the measured shear strength depends upon the initial water content of the sample,pointing to a potential problem that the shear strength could be wrongly determined if not properly interpreted.A shear strength criterion,which enforces the equilibrium condition of pore hydrate,is developed for hydrate-bearing soil,estab-lishing a link between the equilibrium condition and the shear strength.The proposed equation de-scribes well the shear strength characteristics of hydrate-bearing soils,remarkably unifying the effects of pore pressure,temperature,water content and hydrate saturation.

外文关键词：

Hydrate-bearing soilPhase equilibrium conditionShear strengthUnhydrated water contentMechanical behavior

作者：

Yuan Zhou、Jiazuo Zhou、Pan Chen、Changfu Wei

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作者单位：

State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,430071,China

University of Chinese Academy of Sciences,Beijing,100049,China

China University of Geosciences,Wuhan,430074,China

基金：

National Science Foundation of China(NSFC)National Science Foundation of China(NSFC)Youth Innovation Promotion Association,Chinese Academy of Sciences(CAS)

项目编号：

51939011421711352020326

出版年：

2024

DOI：

10.1016/j.jrmge.2023.10.002

岩石力学与岩土工程学报(英文版)

中国科学院武汉岩土力学所中国岩石力学与工程学会武汉大学

岩石力学与岩土工程学报(英文版)

CSTPCD

影响因子：0.404

ISSN：1674-7755

年,卷(期)：2024.16(7)