A state-dependent constitutive model for coarse-grained gassy soil and its application in slope instability modelling

Hong, Y., Wang, X., Wang, L. and Gao, Z. (2021) A state-dependent constitutive model for coarse-grained gassy soil and its application in slope instability modelling. Computers and Geotechnics, 129, 103847. (doi: 10.1016/j.compgeo.2020.103847)

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Free gas in sandy marine sediments is a common occurrence worldwide. A distinct feature of gassy sand is that, under undrained shearing, presence of occluded gas bubbles in the pore fluid can increase the undrained strength of sand at a relatively loose state, while reduce the strength of a relatively dense sand. Previous theoretical analyses have primarily focused on modelling the ‘beneficial’ effect of free gas on loose sand in migrating static liquefaction, with few attempts to describe the ‘detrimental’ effect of gas on dense sand under undrained loading. This study presents a state-dependent critical state model, which describes the distinct behavior of gassy sand with various states in a unified way. Comparison between the model predictions and test data of three gassy sands shows that the new model can capture the constitutive behavior of gassy marine sand over a wide range of initial states and degrees of saturation (typically between 85% and 100% for unsaturated marine sediments) using a single set of parameters. Parametric studies were performed to quantify the effects of gas (either ‘detrimental’ or ‘beneficial’) on sand with various initial states. The new model has been implemented in ABAQUS and used to simulate the stability of submarine slopes under undrained loading condition. It is found that free gas can improve and weaken the slope stability for loose and dense sand, respectively.

Item Type:Articles
Additional Information:The authors gratefully acknowledge the financial supports provided by National Key Research and Development Program (2018YFE0109500), National Natural Science Foundation of China (51779221 and 51939010) and the Key Research and Development Program of Zhejiang Province (2018C03031) and Zhejiang Provincial Natural Science Foundation (LHZ20E090001).
Glasgow Author(s) Enlighten ID:Gao, Dr Zhiwei
Creator Roles:
Gao, Z.Conceptualization, Methodology, Writing – review and editing
Authors: Hong, Y., Wang, X., Wang, L., and Gao, Z.
College/School:College of Science and Engineering > School of Engineering > Infrastructure and Environment
Journal Name:Computers and Geotechnics
ISSN (Online):1873-7633
Published Online:01 November 2020
Copyright Holders:Copyright © 2020 Elsevier Ltd.
First Published:First published in Computers and Geotechnics 129: 103847
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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