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

Tong, Linlong; Liu, Philip L.‐F.

doi:10.1017/jfm.2022.184

Cited by 15 publications

(4 citation statements)

References 51 publications

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“…Two wave-induced seabed liquefaction mechanisms, namely oscillatory and residual, have been reported in the literature [3][4][5]. The former is caused by oscillatory or transient excess pore pressures with phase lag and amplitude attenuation [6][7][8][9][10][11][12], while the latter is the result of the build-up of excess pore pressures due to soil contraction under cyclic loading [4,13]. This study considers both mechanisms.…”

Section: Introductionmentioning

confidence: 98%

Integrated Model for Wave-Induced Oscillatory and Residual Soil Response in a Poro-Elastic Seabed: Partially Dynamic Model

Wan

Cui

Jeng

2023

JMSE

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The evaluation of wave-induced residual pore pressure in a porous seabed and associated seabed liquefaction is essential for designing marine infrastructure foundations. The strength and stiffness of the seabed could be weakened due to the build-up of pore pressures under cyclic wave action, further leading to residual liquefaction. Existing models for residual liquefaction are limited to the quasi-static uncoupled approaches, which do not account for the effect of oscillatory pore pressure on the accumulative pore pressure acceleration of solid particles, despite the mutual influence of these two mechanisms. To overcome these limitations, this paper proposes a new model for residual soil response with u−p approximation (partial dynamic model) that couples oscillatory and residual mechanisms. The proposed model is validated through wave flume tests and centrifuge tests. Based on the coupling model, a new criterion of liquefaction integrating both oscillatory and residual mechanisms is also proposed. Numerical examples demonstrate that the coupling effect significantly affects the wave-induced seabed liquefaction potential. Furthermore, a new parameter (Ω) representing the ratio of oscillatory and residual pore pressure is introduced to clarify which mechanism dominates the pore pressure development.

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Section: Introductionmentioning

confidence: 98%

Integrated Model for Wave-Induced Oscillatory and Residual Soil Response in a Poro-Elastic Seabed: Partially Dynamic Model

Wan

Cui

Jeng

2023

JMSE

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“…(1992) was later extended by Gratiot and Mory (2000) to include the effect of water depth variations. Tong and Liu (2022) continued this work by presenting an analytical solution for the pore pressures within an unsaturated poroelastic seabed under transient waves, where previous studies had assumed simple harmonic waves acting on the seabed. They found that both the potential and duration of various seabed failures, including ML, are highly dependent on sediment properties, such as the saturation degree, the shear modulus, and the sediment permeability.…”

Section: Introductionmentioning

confidence: 99%

Field Observations of Hydrostatic Pressure Deviations in a Nearshore Sediment Bed

Marry,

Foster

2024

JGR Oceans

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Momentary liquefaction (ML), an instantaneous loss of effective stress between individual sand grains, is caused by the upward vertical pressure gradient of the excess pore‐water pressure in the sediment during the passage of a wave. Few field experiments have provided detailed observations of vertical pressure gradients within a sediment bed. Here, a novel autonomous pressure‐profiling instrument, the Pressure Stick, was deployed in the surf zone of an ocean beach in Rye, New Hampshire. The Pressure Stick has eight time‐synced absolute pressure sensors distributed over a 70 cm distance to measure absolute pressure in the water column and in the sediment bed. The absence of direct measurements of the sediment‐water interface location and sediment porosity limit direct observations of ML but allow for an examination of the hydrostatic pressure deviations. Observed upward vertical pressure head gradients within the sediment exceed the assumed effective weight of the sediment. Exceedances of two ML thresholds are observed within 16 cm of the sediment‐water interface and consistently occur at the onset of steeper and larger wave crests. Individual waves are characterized with an approximation of the Sleath parameter and the depth normalized wave height. The ML thresholds are exceeded 1%–40% of the time when the Sleath parameter is greater than 0.1 and 1%–33% of the time when the depth normalized wave height is greater than 0.4. These results suggest that wave steepness and nonlinearity may be necessary to induce large vertical pressure gradients that substantially deviate from hydrostatic pressure.

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“…In the past few decades, the analytical solution for the dynamic response of seabeds subjected to seawater waves has been widely studied (Ulker et al 2 ; Ulker 3 ; Zhou et al 4 ; and Tong and Liu 5 ). Many researchers have discussed the influence F I G U R E 1 Schematic of a seawater-sloping seabed-bedrock system.…”

Section: Introductionmentioning

confidence: 99%

An analytical solution for the dynamic response of a seawater‐sloping seabed‐bedrock system under an oblique incident P wave

Shan

Xie

Dong

et al. 2023

Num Anal Meth Geomechanics

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Many offshore marine structures are built on seabeds with slight or considerable slopes, while most analytical studies have focused on the dynamic responses of horizontal seabeds. Based on the theory of porous media, an analytical solution for the response of a sloping seabed to earthquakes is developed in this paper. Stress and displacement responses can be shown at any location of the seabed.Using numerical examples, we analyze the influence of the slope angle, frequency and angle of incident waves, and thicknesses of the seawater and sediment layers on the dynamic response of the seabed. The results show that the solid displacement amplification factor of the surface of the horizontal seabed is always constant, while that of the sloping seabed changes periodically along the seabed surface. Even at a small site, the difference between a horizontal seabed and a sloping seabed is still significant. The slope angle has different effects on the seabed at different depths, and the inclination plays an amplification role at some depths and a reduction role at other depths. With an increase in slope angle, the difference between a horizontal seabed and a sloping seabed becomes more significant. Especially at natural frequencies, the amplification factor becomes more significant with increasing slope angle. Therefore, even though the same seawater depth is used in the model, a horizontal seabed model cannot be used to analyze the dynamic response of a sloping seabed or significant errors will occur.

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

Cited by 15 publications

References 51 publications

Integrated Model for Wave-Induced Oscillatory and Residual Soil Response in a Poro-Elastic Seabed: Partially Dynamic Model

Integrated Model for Wave-Induced Oscillatory and Residual Soil Response in a Poro-Elastic Seabed: Partially Dynamic Model

Field Observations of Hydrostatic Pressure Deviations in a Nearshore Sediment Bed

An analytical solution for the dynamic response of a seawater‐sloping seabed‐bedrock system under an oblique incident P wave

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