The initial wave induced failure of silty seabed: Liquefaction or shear failure

Ren, Yupeng; Xu, Guowen; Xu, Xingbei; Zhao, Tianlin; Wang, Xinzhi

doi:10.1016/j.oceaneng.2020.106990

Cited by 26 publications

(4 citation statements)

References 23 publications

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“…The results show that the maximum stress angle under the linear wave is 31.6 • , which is around the critical value, 31 • . As shown in figure 20, shear failure may occur near the water-seabed interface in the deceleration phase, which is consistent with Ren et al (2020).…”

Section: Wave-induced Shear Failure Potential Inside the Seabedsupporting

confidence: 83%

Transient wave-induced pore-water-pressure and soil responses in a shallow unsaturated poroelastic seabed

Tong

Liu

2022

J. Fluid Mech.

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An analytical solution is developed for studying transient water wave-induced responses inside an unsaturated poroelastic seabed of finite thickness. The soil skeleton and the pore fluid are compressible and the constitutive relationship of the soil skeleton is described by Hooke's law. Assuming that the horizontal length scale of wave motion is much larger than the seabed thickness, the leading-order analytical solutions for the seabed responses, including pore fluid pressure and soil skeleton motion, are obtained. The present solutions are suitable for general transient wave loading and for the shear modulus of the soil skeleton being of the same order of magnitude as the effective bulk modulus of elasticity of the pore fluid. The present theory is first validated by checking the solutions with the experimental data for the pore pressure induced by periodic-wave loading. The present analytical solutions are then used to investigate the seabed responses under transient waves, including linear periodic wave, a solitary wave and a bore. The effects of the wave-induced effective stresses on the bed failure potential are further analysed. The results show that the shear failure potential and its duration are highly dependent on the soil properties, such as saturation degree, shear modulus and permeability. Sensitivity analyses are presented.

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Section: Wave-induced Shear Failure Potential Inside the Seabedsupporting

confidence: 83%

Transient wave-induced pore-water-pressure and soil responses in a shallow unsaturated poroelastic seabed

Tong

Liu

2022

J. Fluid Mech.

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“…From the Phase I to Phase III, the erosion constant was increased dramatically with the help of the wave (or swell) process (Table 1). The reason for explaining this increasing process can be attributed to the bed liquefaction due to the wave process (Lambrechts et al, 2010;Ren et al, 2020). From the Phase III to the Phase IV, the calibrated erosion constant was increased up to 2×10 -4 kg/m 2 /s under the exclusive deposition paradigm while the calibrated erosion constant under the simultaneous deposition paradigm was remained unchanged, with the value of 2×10 -4 kg/m 2 /s.…”

Section: Performance Of Runs With Different Deposition Modelmentioning

confidence: 99%

Sedimentation of cohesive sediments at the subtidal flat affected by wind wave in high turbidity estuary

Shen

Zhu²,

Lou³

et al. 2023

Front. Mar. Sci.

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Sedimentation is an important mechanism to mitigate the shrinking of tidal flat and to restore its ecological function by means of sand or mud nourishment. To explore the sedimentation of cohesive sediments, a seabed tripod observation system was deployed at the subtidal region of the Hengsha Shoal adjacent to the turbidity maximum zone of the Yangtze Estuary for 11 days. The results showed that the fine sediment with the median grain size around 8 mm occupied the whole water column. The seabed was in relative equilibrium state with the fluctuation of bed level smaller than 16 mm during the moderate wind condition while the seabed experienced a rapid erosion of 38mm and a successive intensive accretion of 68mm during the process of wind wave and swell. The bottom hydrodynamic at 0.3mab during the bed accretion was stronger than that during the bed erosion. The deposition process of cohesive sediments can be better described by the simultaneous deposition paradigm than that by the exclusive deposition paradigm according to the direct data-model comparison of the bed level changes, especially during the impact of fluid mud. Three possible reasons for the better performance of the simultaneous deposition paradigm were proposed. The first possibility is that the fine suspended sediments do maintain a continuous contact with the sediment bed since the direct bed level changes during our observation period has been well reproduced by the simultaneous deposition paradigm. The second possibility is the SSC-induced turbulence damping which facilitates the fine sediment settling in the form of cohesive sediment flocs, indicating the settling of sediments can’t be judged by the critical shear stress for deposition just based on the single particle grain size. The last possibility is the fluid mud-induced overestimated bed shear stress by using turbulent velocity fluctuation above the fluid mud-water interface, which produces excess sediment erosion waiting to be compensated by the simultaneous deposition paradigm. For practical modeling purposes, modeling under the simultaneous deposition paradigm can give satisfactory results for the sedimentation of cohesive sediment especially during the impact of wave or swell.

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“…For instance, Brandon et al [29] demonstrated that static pressure and vibration significantly impact the density of field silt. Phan et al [30] employed drained and undrained triaxial tests on sandy soils to reveal that liquefaction resistance improves with increased rolling resistance of fines [31,32]. Thevanayagam and Martin [33] performed field liquefaction and laboratory permeability tests on silt, indicating that the water content and compaction degree affect both the collapse rate and permeability coefficient.…”

Section: Introductionmentioning

confidence: 99%

Macroscopic and Microscopic Characteristics of Strength Degradation of Silty Soil Improved by Regenerated Polyester Fibers under Dry–Wet Cycling

Liu,

Han,

Liu

et al. 2023

Polymers

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The structural stability of silt foundations, particularly sensitive to moisture content, can be severely compromised by recurring wetting and drying processes. This not only threatens the foundational integrity but also raises grave concerns about the long-term safety of major civil engineering endeavors. Addressing this critical issue, our study delves into the transformative effects of reclaimed polyester fiber on subgrade silt exposed to such environmental stressors. Through rigorous wet–dry cycle tests on this enhanced soil, we evaluate shifts in shear strength across varying confining pressures. We also dissect the interplay between average pore diameter, particle distribution, and morphology in influencing the soil’s microstructural responses to these cycles. A detailed analysis traces the structural damage timeline in the treated soil, elucidating the intertwined micro–macro dynamics driving strength reduction. Key discoveries indicate a notably non-linear trajectory of shear strength degradation, marked by distinct phases of rapid, subdued, and stabilized strength attrition. Alterations within the micropores induce a rise in both their count and size, ultimately diminishing the total volume proportion of the reinforced soil. Intriguingly, particle distribution is directly tied to the wet–dry cycle frequency, while the fractal dimension of soil particles consistently wanes. This research identifies cement hydrolysis and pore expansion as the dominant culprits behind the observed macroscopic strength degradation due to incessant wet–dry cycles. These revelations hold profound implications for risk management and infrastructural strategizing in areas dominated by silt foundations.

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The initial wave induced failure of silty seabed: Liquefaction or shear failure

Cited by 26 publications

References 23 publications

Transient wave-induced pore-water-pressure and soil responses in a shallow unsaturated poroelastic seabed

Transient wave-induced pore-water-pressure and soil responses in a shallow unsaturated poroelastic seabed

Sedimentation of cohesive sediments at the subtidal flat affected by wind wave in high turbidity estuary

Macroscopic and Microscopic Characteristics of Strength Degradation of Silty Soil Improved by Regenerated Polyester Fibers under Dry–Wet Cycling

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