Influence of Principal Stress Orientation on Cyclic Degradation of Soft Clay Under Storm Wave Loading

Coastal marine soft clays subjected to long-term storm wave loading often exhibit inclined initial principal stress orientation (<i>α</i><sub>0</sub>) and subsequent cyclic principal stress rotation (PSR). These stress states critically influence soil mechanical behavior and...

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Bibliographic Details
Main Authors: Chengcong Hu, Feng Gao, Biao Huang, Peipei Li, Zheng Hu, Kun Pan
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Journal of Marine Science and Engineering
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Online Access:https://www.mdpi.com/2077-1312/13/7/1227
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Summary:Coastal marine soft clays subjected to long-term storm wave loading often exhibit inclined initial principal stress orientation (<i>α</i><sub>0</sub>) and subsequent cyclic principal stress rotation (PSR). These stress states critically influence soil mechanical behavior and failure mechanisms, threatening offshore structural stability. This study employs hollow cylinder apparatus testing to investigate the undrained cyclic loading behavior of reconstituted soft clay under controlled <i>α</i><sub>0</sub> and PSR conditions, simulating storm wave-induced stress paths. Results demonstrate that <i>α</i><sub>0</sub> governs permanent pore pressure and vertical strain accumulation with distinct mechanisms, e.g., a tension-dominated response with gradual pore pressure rise at <i>α</i><sub>0</sub> < 45° transitions to a compression-driven rapid strain accumulation at <i>α</i><sub>0</sub> > 45°. Rotational loading with PSR significantly intensifies permanent strain accumulation and stiffness degradation rates, exacerbating soil’s anisotropic behavior. Furthermore, the stiffness degradation index tends to uniquely correlate with the permanent axial or shear strain, which can be quantified by an exponential relationship that is independent of <i>α</i><sub>0</sub> and PSR, providing a unified framework for normalizing stiffness evolution across diverse loading paths. These findings advance the understanding of storm wave-induced degradation behavior of soft clay and establish predictive tools for optimizing marine foundation design under cyclic loading.
ISSN:2077-1312