Experimental Study on Strength Characteristics of Overconsolidated Gassy Clay

Gassy clay, commonly encountered in coastal areas as overconsolidated deposits, demonstrates distinct mechanical properties posing risks for submarine geohazards and engineering stability. Consolidated undrained triaxial tests combined with cyclic simple shear tests were performed on specimens with...

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Main Authors: Tao Liu, Longfei Zhu, Yan Zhang, Chengrong Qing, Yuanzhe Zhan, Chaonan Zhu, Jiayang Jia
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Journal of Marine Science and Engineering
Subjects:
Online Access:https://www.mdpi.com/2077-1312/13/5/904
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author Tao Liu
Longfei Zhu
Yan Zhang
Chengrong Qing
Yuanzhe Zhan
Chaonan Zhu
Jiayang Jia
author_facet Tao Liu
Longfei Zhu
Yan Zhang
Chengrong Qing
Yuanzhe Zhan
Chaonan Zhu
Jiayang Jia
author_sort Tao Liu
collection DOAJ
description Gassy clay, commonly encountered in coastal areas as overconsolidated deposits, demonstrates distinct mechanical properties posing risks for submarine geohazards and engineering stability. Consolidated undrained triaxial tests combined with cyclic simple shear tests were performed on specimens with varying overconsolidation ratios (OCRs) and initial pore pressures, supplemented by SEM microstructural analysis. Triaxial results indicate that OCR controls the transitions between shear contraction and dilatancy, which govern both stress–strain responses and excess pore pressure development. Higher OCR with lower initial pore pressure increases stress path slope, raises undrained shear strength (<i>s</i><sub>u</sub>), reduces pore pressure generation, and induces negative pore pressure at elevated OCR. These effects originate from compressed gas bubbles and limited bubble flooding under overconsolidation, intensifying dilatancy during shear. Cyclic tests reveal gassy clay’s superior cyclic strength, slower pore pressure accumulation, reduced stiffness softening, and enhanced deformation resistance relative to saturated soils. Cyclic pore pressure amplitude increases with OCR, while peak cyclic strength and anti-softening capacity occur at OCR = 2, implying gas bubble interactions.
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issn 2077-1312
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publishDate 2025-04-01
publisher MDPI AG
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series Journal of Marine Science and Engineering
spelling doaj-art-a6518cc3fc674a159cfb88aceb5c24df2025-08-20T01:56:28ZengMDPI AGJournal of Marine Science and Engineering2077-13122025-04-0113590410.3390/jmse13050904Experimental Study on Strength Characteristics of Overconsolidated Gassy ClayTao Liu0Longfei Zhu1Yan Zhang2Chengrong Qing3Yuanzhe Zhan4Chaonan Zhu5Jiayang Jia6Shandong Engineering Research Center of Marine Exploration and Conservation, Ocean University of China, Qingdao 266100, ChinaShandong Engineering Research Center of Marine Exploration and Conservation, Ocean University of China, Qingdao 266100, ChinaKey Laboratory of Intelligent Underground Detection Technology, Anhui Jianzhu University, Hefei 230000, ChinaShandong Engineering Research Center of Marine Exploration and Conservation, Ocean University of China, Qingdao 266100, ChinaShandong Engineering Research Center of Marine Exploration and Conservation, Ocean University of China, Qingdao 266100, ChinaShandong Engineering Research Center of Marine Exploration and Conservation, Ocean University of China, Qingdao 266100, ChinaShandong Engineering Research Center of Marine Exploration and Conservation, Ocean University of China, Qingdao 266100, ChinaGassy clay, commonly encountered in coastal areas as overconsolidated deposits, demonstrates distinct mechanical properties posing risks for submarine geohazards and engineering stability. Consolidated undrained triaxial tests combined with cyclic simple shear tests were performed on specimens with varying overconsolidation ratios (OCRs) and initial pore pressures, supplemented by SEM microstructural analysis. Triaxial results indicate that OCR controls the transitions between shear contraction and dilatancy, which govern both stress–strain responses and excess pore pressure development. Higher OCR with lower initial pore pressure increases stress path slope, raises undrained shear strength (<i>s</i><sub>u</sub>), reduces pore pressure generation, and induces negative pore pressure at elevated OCR. These effects originate from compressed gas bubbles and limited bubble flooding under overconsolidation, intensifying dilatancy during shear. Cyclic tests reveal gassy clay’s superior cyclic strength, slower pore pressure accumulation, reduced stiffness softening, and enhanced deformation resistance relative to saturated soils. Cyclic pore pressure amplitude increases with OCR, while peak cyclic strength and anti-softening capacity occur at OCR = 2, implying gas bubble interactions.https://www.mdpi.com/2077-1312/13/5/904overconsolidated gassy clayconsolidation testtriaxial testcyclic simple shear testnumerical simulation
spellingShingle Tao Liu
Longfei Zhu
Yan Zhang
Chengrong Qing
Yuanzhe Zhan
Chaonan Zhu
Jiayang Jia
Experimental Study on Strength Characteristics of Overconsolidated Gassy Clay
Journal of Marine Science and Engineering
overconsolidated gassy clay
consolidation test
triaxial test
cyclic simple shear test
numerical simulation
title Experimental Study on Strength Characteristics of Overconsolidated Gassy Clay
title_full Experimental Study on Strength Characteristics of Overconsolidated Gassy Clay
title_fullStr Experimental Study on Strength Characteristics of Overconsolidated Gassy Clay
title_full_unstemmed Experimental Study on Strength Characteristics of Overconsolidated Gassy Clay
title_short Experimental Study on Strength Characteristics of Overconsolidated Gassy Clay
title_sort experimental study on strength characteristics of overconsolidated gassy clay
topic overconsolidated gassy clay
consolidation test
triaxial test
cyclic simple shear test
numerical simulation
url https://www.mdpi.com/2077-1312/13/5/904
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AT longfeizhu experimentalstudyonstrengthcharacteristicsofoverconsolidatedgassyclay
AT yanzhang experimentalstudyonstrengthcharacteristicsofoverconsolidatedgassyclay
AT chengrongqing experimentalstudyonstrengthcharacteristicsofoverconsolidatedgassyclay
AT yuanzhezhan experimentalstudyonstrengthcharacteristicsofoverconsolidatedgassyclay
AT chaonanzhu experimentalstudyonstrengthcharacteristicsofoverconsolidatedgassyclay
AT jiayangjia experimentalstudyonstrengthcharacteristicsofoverconsolidatedgassyclay