Academic literature on the topic 'Seabed liquefaction'
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Journal articles on the topic "Seabed liquefaction"
1
Chai, Xiuwei, Jingyuan Liu, and Yu Zhou. "Cnoidal Wave-Induced Residual Liquefaction in Loosely Deposited Seabed under Coastal Shallow Water." Applied Sciences 11, no. 24 (2021): 11631. http://dx.doi.org/10.3390/app112411631.
Full textAbstract:
This study is aimed at numerically investigating the cnoidal wave-induced dynamics characteristics and the liquefaction process in a loosely deposited seabed floor in a shallow water environment. To achieve this goal, the integrated model FSSI-CAS 2D is taken as the computational platform, and the advanced soil model Pastor–Zienkiewicz Mark III is utilized to describe the complicated mechanical behavior of loose seabed soil. The computational results show that a significant lateral spreading and vertical subsidence could be observed in the loosely deposited seabed floor due to the gradual loss of soil skeleton stiffness caused by the accumulation of pore pressure. The accumulation of pore pressure in the loose seabed is not infinite but limited by the liquefaction resistance line. The seabed soil at some locations could be reached to the full liquefaction state, becoming a type of heavy fluid with great viscosity. Residual liquefaction is a progressive process that is initiated at the upper part of the seabed floor and then enlarges downward. For waves with great height in shallow water, the depth of the liquefaction zone will be greatly overestimated if the Stokes wave theory is used. This study can enhance the understanding of the characteristics of the liquefaction process in a loosely deposited seabed under coastal shallow water and provide a reference for engineering activities.
2
Zhang, Jun, Qin Jiang, Dongsheng Jeng, Changkuan Zhang, Xindi Chen, and Lizhu Wang. "Experimental Study on Mechanism of Wave-Induced Liquefaction of Sand-Clay Seabed." Journal of Marine Science and Engineering 8, no. 2 (2020): 66. http://dx.doi.org/10.3390/jmse8020066.
Full textAbstract:
In this study, a series of laboratory experiments for the response of wave induced clay-sand seabed were carried out to clarify the mechanism of liquefaction of clayey seabed. The experiments were conducted in an 80 m long wave flume. In the tests, the sand-clay beds were mixed with various clay contents (CC) from 0.5% to 15% and were tested for given wave conditions. The pore water pressure and the water elevation were measured in each test. Soil properties tests and scanning electron microscope (SEM) experiments on different seabed samples were carried out to further explore the mechanism of liquefaction. The experimental results indicated that the amplitude and accumulation of the excess pore water pressure (EPP) varied with different CC in the sand-clay bed. With the introduction of CC, micro-structure and properties (such as permeability and compressibility) of bed soils changed. Sand-clay bed presented more susceptibility to liquefy compared with pure sand bed. CC promoted seabed liquefaction, even if the added amount was very small (CC is 0.5%), however when CC exceeded a certain value (10% in this study), the mixed bed will not be liquefied. This phenomenon can be well explained by the micro-structure of sand-clay bed. CC within a sandy seabed, does not only affect the permeability, but also change the compressibility of seabed soils. For example, the microfabric of seabed vulnerable to liquefaction is loose. Clay aggregations generally gathered at the sand particle contact points. This microfabric is easily compressed under wave loads and allowed pore water to flow, resulting in the accumulation of pore water pressure. On the other hand, the microfabric of seabed that was resistant to liquefaction appeared to be more compact. Due to clay-filled gaps between the sand particles, the pore water is more difficult to flow when seabed was compressed. Furthermore, the tendency of seabed liquefaction is closely related to CC.
3
Huang, Yu, and Xu Han. "Features of Earthquake-Induced Seabed Liquefaction and Mitigation Strategies of Novel Marine Structures." Journal of Marine Science and Engineering 8, no. 5 (2020): 310. http://dx.doi.org/10.3390/jmse8050310.
Full textAbstract:
With the accelerated development of marine engineering, a growing number of marine structures are being constructed (e.g., seabed pipelines, drilling platforms, oil platforms, wind turbines). However, seismic field investigations over recent decades have shown that many marine structures were damaged or destroyed due to liquefaction. Seismic liquefaction in marine engineering can have huge financial repercussions as well as a devastating effect on the marine environment, which merits our great attention. As the effects of seawater and the gas component in the seabed layers are not negligible, the seabed soil layers are more prone to liquefaction than onshore soil layers, and the liquefied area may be larger than when liquefaction occurs on land. To mitigate the impact of liquefaction events on marine engineering structures, some novel liquefaction-resistant marine structures have been proposed in recent years. This paper reviews the features of earthquake-induced liquefaction and the mitigation strategies for marine structures to meet the future requirements of marine engineering.
4
Chen, Linya, Dong-Sheng Jeng, Chencong Liao, and Dagui Tong. "Wave-Induced Seabed Response around a Dumbbell Cofferdam in Non-Homogeneous Anisotropic Seabed." Journal of Marine Science and Engineering 7, no. 6 (2019): 189. http://dx.doi.org/10.3390/jmse7060189.
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Cofferdams are frequently used to assist in the construction of offshore structures that are built on a natural non-homogeneous anisotropic seabed. In this study, a three-dimensional (3D) integrated numerical model consisting of a wave submodel and seabed submodel was adopted to investigate the wave–structure–seabed interaction. Reynolds-Averaged Navier–Stokes (RANS) equations were employed to simulate the wave-induced fluid motion and Biot’s poroelastic theory was adopted to control the wave-induced seabed response. The present model was validated with available laboratory experimental data and previous analytical results. The hydrodynamic process and seabed response around the dumbbell cofferdam are discussed in detail, with particular attention paid to the influence of the depth functions of the permeability K i and shear modulus G j . Numerical results indicate that to avoid the misestimation of the liquefaction depth, a steady-state analysis should be carried out prior to the transient seabed response analysis to first determine the equilibrium state caused by seabed consolidation. The depth function G j markedly affects the vertical distribution of the pore pressure and the seabed liquefaction around the dumbbell cofferdam. The depth function K i has a mild effect on the vertical distribution of the pore pressure within a coarse sand seabed, with the influence concentrated in the range defined by 0.1 times the seabed thickness above and below the embedded depth. The depth function K i has little effect on seabed liquefaction. In addition, the traditional assumption that treats the seabed parameters as constants may result in the overestimation of the seabed liquefaction depth and the liquefaction area around the cofferdam will be miscalculated if consolidation is not considered. Moreover, parametric studies reveal that the shear modulus at the seabed surface G z 0 has a significant influence on the vertical distribution of the pore pressure. However, the effect of the permeability at the seabed surface K z 0 on the vertical distribution of the pore pressure is mainly concentrated on the seabed above the embedded depth in front and to the side of the cofferdam. Furthermore, the amplitude of pore pressure decreases as Poisson’s ratio μ s increases.
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Dong, Jiangfeng, Jishang Xu, Guangxue Li, et al. "Experimental Study on Silty Seabed Liquefaction and Its Impact on Sediment Resuspension by Random Waves." Journal of Marine Science and Engineering 10, no. 3 (2022): 437. http://dx.doi.org/10.3390/jmse10030437.
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Seabed liquefaction and sediment resuspension under wave loading are key issues in marine engineering, but are usually regarded as independent processes (instead of coexisting and interacting processes). Here, we analyzed random wave-induced seabed liquefaction and its impact on sediment resuspension using flume experiments. Results show that in a nonliquefaction scenario, excess pore pressure in the seabed oscillates with wave fluctuations, but pressure accumulation is low, while a consistent upward pressure gradient promotes sediment suspension. Wave-induced shear stress was the key driver of sediment resuspension in a nonliquefaction scenario. In the liquefied state, waves with different amplitudes differently responded to excess pore pressure; small-amplitude waves accumulated pressure, while large-amplitude waves dissipated it. Liquefied soil formed mud waves, creating elliptical motion along with random waves. Seabed liquefaction accelerated sediment resuspension in the following ways: reducing soil critical shear stress; forming seepage channels inside the seabed; forming mud waves, resulting in increased turbulent kinetic energy; dissipating excess pore pressure and releasing porewater, expelling fine-grained sediment from the liquefied soil. Our study reveals the variation in excess pore pressure in silty seabed under random waves and its effect on sediment resuspension, which is significant for understanding soil liquefaction and sediment movement of silt.
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Tong, Dagui, Chencong Liao, Jinjian Chen, and Qi Zhang. "Numerical Simulation of a Sandy Seabed Response to Water Surface Waves Propagating on Current." Journal of Marine Science and Engineering 6, no. 3 (2018): 88. http://dx.doi.org/10.3390/jmse6030088.
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An integrated numerical model is developed to study wave and current-induced seabed response and liquefaction in a flat seabed. The velocity-inlet wave-generating method is adopted in the present study and the finite difference method is employed to solve the Reynolds-averaged Navier-Stokes equations with k-ε turbulence closure. The model validation demonstrates the capacity of the present model. The parametrical study reveals that the increase of current velocity tends to elongate the wave trough and alleviate the corresponding suction force on the seabed, leading to a decrease in liquefaction depth, while the width of the liquefaction area is enlarged simultaneously. This goes against previous studies, which ignored fluid viscosity, turbulence and bed friction.
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Duran, Gerardo, Juan Manuel Mayoral, Edgar Mendoza, and Rodolfo Silva. "SEABED INSTABILITY AROUND CAISSON BREAKWATERS." Coastal Engineering Proceedings 1, no. 33 (2012): 13. http://dx.doi.org/10.9753/icce.v33.posters.13.
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A sensibility numerical study, considering the soil conditions found at Frontera Port in Tabasco, Mexico was conducted to identify the variables that govern the response of a seabed-foundation-structure system subject to wave loading. Among all the possible causes of instability, this study deals only with those associated with liquefaction failure of silty-sands due to cyclic shear stresses generated by regular waves. This research was prompted by the accidents that have occurred near Frontera Port, the most serious of which took place in October 2007 when the Usumacinta oil platform settled, causing 21 fatalities. Previous analysis of this accident (Leis, et al, 2007) suggested that the platform did not present any structural failure and that the accident was a result of an unexpected behavior of the seabed; probably liquefaction. In order to offer results regarding coastal protection activities in the study area, the analysis presented here was developed simulating a vertical breakwater similar to that constructed in 2001 at Barcelona instead of the oil platform. Puzrin, et al, 2009 report that in November 2001 four caissons of this breakwater failed due to seabed liquefaction. The adaptation of the design of the vertical breakwater to the study area conditions was estimated by means of the Goda, 1985 formula.
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Shanmugasundaram, Ranjith khumar, Henrik Rusche, Christian Windt, Özgür Kirca, Mutlu Sumer, and Nils Goseberg. "Towards the Numerical Modelling of Residual Seabed Liquefaction Using OpenFOAM." OpenFOAM® Journal 2 (May 21, 2022): 94–115. http://dx.doi.org/10.51560/ofj.v2.56.
Full textAbstract:
Knowledge of the interaction between free surface waves and the seabed is required for the reliable design of marine structures, preventing severe structural failures. To that end, this paper presents the numerical modelling of wave-induced residual liquefaction of seabed soil. An OpenFOAM® finite volume solver is developed to simulate the behaviour of pore pressure and shear stress in the soil and is validated against analytical reference data. The soil is considered as a poro-elastic solid and an additional equation is solved for the pore pressure buildup. The governing equations are valid only up to the onset of liquefaction. A criterion based on the accumulated pore pressure is applied in order to predict the onset of residual liquefaction. The results show that the pore pressure and shear stresses are in good agreement with the analytical results and the relative errors are less than three percent. Also, the numerical results indicate that the wave induced residual liquefaction originates from the mudline and progresses slowly down the soil which is consistent with the analytical results. The pore pressure buildup for a seabed with stone columns shows that the liquefaction potential is very low near the stone column.
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Chen, Xi, Qi Zhang, Xiang Yuan Zheng, and Yu Lei. "Dynamic Responses of a Multilayered Transversely Isotropic Poroelastic Seabed Subjected to Ocean Waves and Currents." Journal of Marine Science and Engineering 10, no. 1 (2022): 73. http://dx.doi.org/10.3390/jmse10010073.
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In this study, a semi-analytical solution to the dynamic responses of a multilayered transversely isotropic poroelastic seabed under combined wave and current loadings is proposed based on the dynamic stiffness matrix method. This solution is first analytically validated with a single-layered and a two-layered isotropic seabed and then verified against previous experimental results. After that, parametric studies are carried out to probe the effects of the soil’s anisotropic characteristics and the effects of ocean waves and currents on the dynamic responses and the maximum liquefaction depth. The results show that the dynamic responses of a transversely isotropic seabed are more sensitive to the ratio of the soil’s vertical Young’s modulus to horizontal Young’s modulus (Ev/Eh) and the ratio of the vertical shear modulus to Ev (Gv/Ev) than to the vertical-to-horizontal ratio of the permeability coefficient (Kv/Kh). A lower degree of quasi-saturation, higher porosity, a shorter wave period, and a following current all result in a greater maximum liquefaction depth. Moreover, it is revealed that the maximum liquefaction depth of a transversely isotropic seabed would be underestimated under the isotropic assumption. Furthermore, unlike the behavior of an isotropic seabed, the transversely isotropic seabed tends to liquefy when fully saturated in nonlinear waves. This result supplements and reinforces the conclusions determined in previous studies. This work affirms that it is necessary for offshore engineering to consider the transversely isotropic characteristics of the seabed for bottom-fixed and subsea offshore structures.
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Xu, Jishang, Xingyu Xu, Yaqi Zhang, et al. "Experimental Study on the Influence of Pipeline Vibration on Silty Seabed Liquefaction." Water 14, no. 11 (2022): 1782. http://dx.doi.org/10.3390/w14111782.
Full textAbstract:
Free-spanning submarine pipelines are usually affected by vortex-induced vibration (VIV). Such vibration could influence the liquefaction of the supporting soil at both ends of the free spans and could have catastrophic consequences, including the failure of the local seabed and the displacing, sinking, or floating of pipelines. The influence of pipeline vibration on soil liquefaction has not been studied sufficiently. Therefore, we explored the influence of vortex-induced pipeline vibration on the excess pore pressure of silty soil around a pipeline using flume experiments. Our results showed that pipeline vibration could induce the buildup of excess pore-water pressure, even without wave loading. A fully liquefied zone was found close to the pipeline, where excess pore pressure reached the soil liquefaction criterion, which was surrounded by a partially liquefied zone. The extent of liquefaction depended on the vibration conditions and the weight and burial depth of the pipeline. The pipeline vibration amplitude increased after soil liquefaction. Unlike wave-induced liquefaction, pipeline-induced vibration liquefaction occurred at a critical value smaller than the initial mean normal effective stress. Considering the possibility of pipeline-vibration-induced seabed liquefaction, conventional approaches could underestimate the potential risks to pipeline stability and result in unsafe maintenance practices.
Dissertations / Theses on the topic "Seabed liquefaction"
1
Li, Zhengxu. "Seabed Instability around a Submerged Breakwater due to Dynamic Loadings." Thesis, Griffith University, 2019. http://hdl.handle.net/10072/387387.
Full textAbstract:
A breakwater is one of common offshore structures for protecting ports and coastlines.
Dynamic response of a seabed around a breakwater caused by the interactions between waves
and currents is a critical aspect in evaluating the stability of the breakwater foundation. The
existence of breakwater does not only affect the propagation pattern of nearby waves but also
has a particular influence on the stability of the surrounding seabed. Under the interaction of
waves and currents, liquefaction of the seabed foundation is one of main causes of breakwater
damage, which must be fully considered in the design and construction of breakwaters. The
periodic motion of waves exerts a cyclical pressure on the interface between seawater and
seabed. Due to the effect of the cyclic wave pressures, the wave-induced residual pore
pressure will increase, and the effective stress will decrease in the seabed, which could cause
soil displacements and seabed deformation. Thus, under certain conditions, the shear failure
and liquefaction of the seabed will occur. Furthermore, under the action of cyclic wave
pressure, the normal stress and shear stress of the soil element in the seabed are cyclically
changed which will cause the principal stress axis continuously to rotate. As a consequence,
the plastic deformation of the soil is more significant, and the seabed is more prone to
liquefaction.
In this study, a one-way coupled two-dimensional numerical model is established integrating
the fluid model and the seabed model. The soil liquefaction caused by the excess
pore water pressure in the seabed is calculated by using the elasto-plastic porous medium
soil model. The feasibility of the model was verified by comparison with the laboratory
experiments, the centrifuge tests, and the previous numerical model data. It is shown that
the numerical model can simulate the dynamic response of the seabed under wave-current
interaction with high accuracy.
By adopting the integrated numerical model, the dynamic seabed response generated by
the rotation of the principal stress (PSR) axis is analysed under the cyclic wave loading. It is
found that the PSR will affect the seabed dynamic response significantly. The liquefaction
depth of the case considered PSR is much deeper than the results which did not consider the
PSR effects, since the plastic strain of the soil caused by the PSR is involved in. Secondly,
the dynamic response of seabed under different uniform current velocity and different wave conditions are solved. It is found that the following current accelerates the accumulation of
pore water pressure, increases the displacement of the soil, and makes the seabed easier to
liquefy, while the opposing current has an opposite effect. Also, the dynamic response of the
seabed under wave loading is calculated, and detailed parameter analysis of the liquefaction
potential of the seabed are carried out, including wave parameters (wave height, wave period),
and seabed parameters (soil permeability, degree of saturation).
In order to figure out the influence of the breakwater, a new-developed coupled model
is established to simulate wave-seabed-breakwater interactions under cyclic wave loading.
Firstly, the consolidation of the seabed under the effect of the self-weight of the breakwater
is calculated. The dynamic response of the seabed around the breakwater and the seabed
liquefaction depth are computed after consolidation process. Secondly, the interaction
between wave and submerged breakwater is studied by the coupled numerical model. The
influence of the height and crest width of the breakwater on the wave propagation is analysed.
The variations of wave height in front of and behind the breakwater are compared. At the
same time, the influence of breakwater height and crest width on liquefaction depth and
liquefaction potential of seabed under wave action is analysed.<br>Thesis (Masters)<br>Master of Philosophy (MPhil)<br>School of Eng & Built Env<br>Science, Environment, Engineering and Technology<br>Full Text
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Han, Shuang. "Liquefaction around a Submarine Tunnel under Natural Dynamic Loading." Thesis, Griffith University, 2020. http://hdl.handle.net/10072/399434.
Full textAbstract:
Seabed instability surrounding an immersed tunnel is a vital engineering issue regarding the design and maintenance for submarine tunnel projects. It has been recognised that the pore water pressures and stresses in seabeds are affected by the water pressures generated by the natural dynamic loading. If the pore water pressure reaches the initial mean stress, the liquefaction could occur with the effective stress in seabed vanishing. To avoid seabed instability around the immersed tunnel, the study of seabed dynamic behaviour is necessary under the real hydrodynamic loading.
Two mechanisms of wave-induced liquefaction has been reported in the literature, based on a mass of laboratory tests and field exploration, which are transient liquefaction and residual liquefaction. The transient liquefaction is motivated by the oscillatory excess pore water pressures under wave pressure vibration which usually happens with amplitude reduction and phase lag of pore pressure in seabed soil. While the residual liquefaction is on the consequence of the excess pore water pressure build-up under cyclic wave loading. The liquefied seabed soil will behave like a heavy fluid without any shear resistance to supported structures on it, thus leading to catastrophic failure of the immersed tunnel. In the present study, the main objective is to investigate the mechanism of soil response and liquefaction caused by waves and currents in the seabed foundation around the immersed tunnel.
An integrated numerical model is established to analysis the seabed behaviour under natural dynamic loading, including ocean waves and currents. In the integrated model, the fluid sub-model is responsible for simulating the two-phase incompressible flow motion inside and outside the porous media, which is governed by the VARANS (Volume-Averages Reynolds Averaged Navier-Stokes) equation, while the seabed model is established adopting the LRBFCM with Biot’s "u− p" approximation which considered the inertial term of soil skeleton. The new conceptual meshfree model for residual mechanism considers the coupling effects between the development of the pore pressure build-up and the evolution of the seabed stresses by adding a source term associated with the shear stresses in the seabed. Good agreements with analytical solution and laboratory experiments validates this newly proposed numerical model. The LRBFCM is examined to be reliable in simulation of wave-induced oscillatory and residual liquefaction behaviour of a seabed.
The wave-induced dynamic response of the oscillatory and residual seabed response is investigated adopting the developed integrated model. A series of results, including the seabed stresses, the pore pressure accumulation and the liquefaction potential in the seabed foundation are obtained.
The existence of the immersed tunnel affects surrounding seabed dynamic behaviours significantly, including the seabed stresses and the pore water pressures, leading to the local redistribution in the adjacent region of the immersed tunnel. Both the maximum oscillatory and residual liquefied depth on the right-hand side of the tunnel is smaller than that on the left-hand side (the ocean wave is set as propagating along the x-direction from the left-hand side to the right-hand side). From the numerical results, the seabed oscillatory liquefaction is more likely to occur under a shallow water area with the waves of large wave height and long period, moreover, a seabed with lower permeability and degree of saturation is more likely to be liquefied. For the residual seabed response, the residual liquefaction is more likely to occur in the seabed foundations with low relative density and poor drainage condition.
The seabed response around the immersed tunnel under combined nonlinear Stocks waves and currents loading is investigated both in oscillatory and residual mechanisms. The simulation results show that the risks of both oscillatory and residual liquefaction are much higher for the seabed under wave combined following currents, and the appearance of opposing current could decreased the probability of the liquefaction occurrence.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>School of Eng & Built Env<br>Science, Environment, Engineering and Technology<br>Full Text
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Cui, Lin. "Three-dimensional Numerical Model for Seabed Foundation Stability around Breakwaters." Thesis, Griffith University, 2020. http://hdl.handle.net/10072/395539.
Full textAbstract:
With the increasing demand for coastal zones from human activities, a growing number of breakwaters have been constructed around the main beach and major estuaries to defend against wave erosion and damage. The vulnerability of the breakwater foundation can be associated with dynamic soil responses in the vicinity of structure when subjects to the consecutive ocean wave loading. For the severe situations, soil liquefaction may occur around the breakwater foundation, which is considered as a significant cause of catastrophic failures of many marine structures. Therefore, understanding and predicting soil responses and liquefaction potential around breakwaters have become one of the main concerns when design and maintain these marine structures.
The traditional models used to analyse the soil responses and liquefaction potential in the neighbourhood of breakwaters were mostly limited to two-dimensional (2D) frameworks, in which only the middle cross-section of the breakwaters under perpendicular waves can be investigated. However, the natural environment is three-dimensional (3D) that involves much more complicated fluid-seabed-structure interactions, which requires a 3D model. What’s more, most of the existing models assumed the seabed foundation as poro-elastic medium, which only the oscillatory soil responses and momentary liquefaction can be studied. Nevertheless, the residual soil responses and liquefaction within the poro-elastoplastic soil are more significant and can cause more severe damage to the marine structure foundations. Another deficiency of the traditional models is the lack of advanced Computational Fluid Dynamic (CFD) model to accurately simulate more realistic conditions, for example, including the interactions of ocean currents.
According to the gaps in previous literature, the main objective of this thesis is defined as numerically predicting the soil responses and examining the breakwater foundation stability (i.e., liquefaction potential) under combined waves and currents loading within both poroelastic and poro-elastoplastic seabed foundation from both two- and three-dimensional perspectives for different engineering conditions. One of the main novel contributions of this study is to develop the integrated numerical model that make up for the deficiency of the fluid-seabed-structure interactions problems mentioned above: the wider application ranges including complicated 3D situations; the consideration of poro-elastoplastic soil behaviour and corresponding soil liquefaction; the inclusion of an advanced flow model to precisely predict the hydrodynamic behaviour around the structures. In the future, the models can be further developed and applied to practical engineering analyses, providing preliminary results for the design of the projects.
The integrated numerical model consists of the flow sub-model, the seabed sub-model and the coupling module between two sub-models. The flow model is developed based on the Finite Volume Method (FVM) by solving the Volume-Averaged Reynolds Averaged Navier-Stokes (VARANS) equations for simulating the two incompressible phases (i.e., water and air) inside and outside the porous medium. The seabed model is governed by the dynamic Biot’s equations known as the u− p approximations, in which the relative displacements of pore fluid to soil particles are ignored and the acceleration of pore fluid and solid particles is included. Two constitutive models: poro-elastic model for oscillatory soil responses and momentary liquefaction; and poro-elastoplastic model for residual soil responses and residual liquefaction, are incorporated into the seabed model. An integration module is developed between flow sub-model and seabed sub-model through pressure continuity on the common faces. A set of validation works have been done to prove the capability of simulating the fluid-seabed-breakwater interactions in an accurate way.
By adopting the integrated numerical model, three numerical studies have been conducted in this thesis, including one 2D study (soil responses around submerged breakwaters with Bragg reflection) and two 3D studies (seabed foundation stability around breakwaters at river mouth; seabed foundation stability around offshore detached breakwaters). A series of results, including the hydrodynamic properties of flow domain, variation of pore pressure, effective stresses and soil displacements, and characteristics of soil liquefaction within both poro-elastic and poro-elastoplastic seabed foundation have been obtained. Numerical results revealed that the construction of breakwaters can dramatically change the flow pattern and stress state in the vicinity, which will further affect the assessment of foundation stability. Besides, compared to the poro-elastic seabed foundation, the liquefaction is much easier to occur in the poro-elastoplastic seabed foundation and usually will develop to a much more significant level, which can cause critical failure of the structures. Furthermore, the effects of wave characteristics and soil properties on the breakwater foundation stability have been examined through parametric studies: the soil liquefaction is more serious within the loosely deposited seabed with poor drainage conditions under large wave height and wave period. It was also found that the currents have remarkable effects on foundation stability that aggravate with the increase of currents velocity.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>School of Eng & Built Env<br>Science, Environment, Engineering and Technology<br>Full Text
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Cha, Dea Ho. "Prediction of Wave-Induced Seabed Maximum Liquefaction Depth Using Artificial Neural Network Model." Thesis, Griffith University, 2010. http://hdl.handle.net/10072/367451.
Full textAbstract:
In the last few decades, considerable effort has been devoted to the phenomenon of wave-induced liquefaction. In deed, it is one of the most important factors used in analysing
the seabed stability and in designing marine structures. As waves propagate and fluctuate
over the ocean surface, energy is carried within the medium of the water particles. When
this energy is transmitted into the seabed, the results are a rather complex mechanism of
soil behaviours that significantly affect the stability of the seabed.
The prediction of wave-induced seabed liquefaction has been recognised by coastal
geotechnical engineers as an important factor when considering the design of marine
structures. All existing prediction of wave-induced seabed liquefaction models have been
based on conventional approaches of engineering mechanics, with limited laboratory work.
Previous studies have involved complicated procedures and complex mathematical methods.
The present meticulous study has been based on the existing poro-elastic wave-induced
seabed liquefaction solution, and has adopted Artificial Intelligence (AI) technology to
predict maximum wave-induced seabed liquefaction. The author has proposed an alternative
approach for prediction of the maximum liquefaction depth, based on the Artificial
Neural Network (ANN). Unlike previous engineering mechanical approaches, the various
proposed ANN models are based on data learning knowledge, rather than on the knowledge
of the mechanisms. The author has concluded that ANN models can be applicable
to such engineering exercise at least this study.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>Griffith School of Engineering<br>Science, Environment, Engineering and Technology<br>Full Text
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Sui, T., C. Zhang, D.-S. Jeng, et al. "Wave-induced seabed residual response and liquefaction around a mono-pile foundation with various embedded depth." Elsevier, 2018. http://hdl.handle.net/10454/17990.
Full textAbstract:
Yes<br>Wave-induced seabed instability caused by the residual liquefaction of seabed may threaten the safety of an offshore foundation. Most previous studies have focused on the structure that sits on the seabed surface (e.g., breakwater and pipeline), a few studies investigate the structure embedded into the seabed (e.g. a mono-pile). In this study, by considering the inertial terms of pore fluid and soil skeleton, a three-dimensional (3D) integrated model for the wave-induced seabed residual response around a mono-pile is developed. The model is validated with five experimental tests available in the literature. The proposed model is then applied to investigate the spatial and temporal pattern of pore pressure accumulation as well as the 3D liquefaction zone around a mono-pile. The numerical simulation shows that the residual pore pressure in front of a pile is larger than that at the rear, and the seabed residual response would be underestimated if the inertial terms of pore fluid and soil skeleton are neglected. The result also shows that the maximum residual liquefaction depth will increase with the increase of the embedded depth of the pile.<br>This work was supported by the Fundamental Research Funds for the Central Universities [2017B15814], the International Postdoctoral Exchange Fellowship Program [20170014], National Science Foundation for Distinguished Young Scholars [Grant No. 51425901], Fundamental Research Funds for the Central Universities (2017B21514), Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province (2018SS02), Natural Science Foundation of Jiangsu Province [Grant No. BK20161509] and Open Foundation of State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University [Project No: 2016491011].
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Vun, Pui Lee. "Experimental and numerical studies on wave-induced liquefaction to soil around marine structures founded in the seabed." Thesis, University of Birmingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420398.
Full textAbstract:
The main objective of this research is to investigate the problem of wave-induced liquefaction around two marine structures, which are suction caisson foundation and buried marine pipeline, using experimental and numerical approaches. Both experimental and numerical approaches were used to investigate the instability of suction caissons foundation founded in an unstable and liquefied seabed. Only finite element analysis was performed to examine the liquefaction potential of soil around a buried pipeline in a seabed subjected to progressive wave loading. The Finite Element computer program, namely SWANDYNE II (HR version), was used for all the numerical analyses in plane strain (two-dimensional) case; and its capability in simulating the wave-induced seabed responses was successfully verified using the analytical solution proposed by Hsu and Jeng (1994). In this study, a total of 82 model scale wave flume tests were conducted to investigate the instabilities of suction caisson foundations in loose, medium dense and dense silt beds subjected to various progressive wave loadings. Pore water pressure responses around the skirt tip and beneath the top cap were measured by pore pressure transducers during the tests. Residual liquefaction was observed to occur to the silt bed with a relative density of less than 80%. A valve located at the top cap of the caisson was used to control the direct inflow and outflow of water inside of the caisson. The opening on the top cap could affect the pore water pressure behaviour of soil around the caisson significantly. The pressure difference between the top and the bottom of the top cap increases when the top cap is totally impermeable (shut valve), and this can be affected by the wavelength and the compressibility of the fluid. The suction caisson was idealised as a two-dimensional plane strain problem based on its bending stiffness. The dense seabed was modelled by either Linear Elastic model or General Elastic model with Mohr-Coulomb cap and the numerical solution has a good agreement with the experimental result. The parametric studies on the wave conditions, as well as on the soil parameters, were conducted under consolidation condition in prototype scale (full scale) to investigate (i) the liquefaction potential around the outside of the skirt, (ii) the oscillatory variation in skin friction acting on the skirt, and (iii) the pressure difference across the top cap of the caisson. It was found that only momentary liquefaction occurred to the top layer of soil around the caisson foundation when the seabed was subjected to severe wave loading. Finite element study on the instability of a buried marine pipeline founded in a seabed subjected to wave loading was performed and an elasto-plastic constitutive model of Pastor-Zienkiewicz Mark-III Model (PZ3) was adopted to model the seabed. The applicability of this model to the wave-induced liquefaction to seabed was successfully validated by the experimental data from Teh (2003). The parametric studies on the pipe and trench geometries, the wave conditions and the soil parameters, were conducted under the consolidation condition in prototype scale. Most of the experimental findings from Sumer et al. (2004) and Teh et at. (2004) were successfully reproduced by the numerical analyses.
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Shabani, Behnam. "Wave-Associated Seabed Behaviour near Submarine Buried Pipelines." University of Sydney, 2008. http://hdl.handle.net/2123/3532.
Full textAbstract:
Master of Engineering (Research)<br>Soil surrounding a submarine buried pipeline consolidates as ocean waves propagate over the seabed surface. Conventional models for the analysis of soil behaviour near the pipeline assume a two-dimensional interaction problem between waves, the seabed soil, and the structure. In other words, it is often considered that water waves travel normal to the orientation of pipeline. However, the real ocean environment is three-dimensional and waves approach the structure from various directions. It is therefore the key objective of the present research to study the seabed behaviour in the vicinity of marine pipelines from a three-dimensional point of view. A three-dimensional numerical model is developed based on the Finite Element Method to analyse the so-called momentary behaviour of soil under the wave loading. In this model, the pipeline is assumed to be rigid and anchored within a rigid impervious trench. A non-slip condition is considered to exist between the pipe and the surrounding soil. Quasi-static soil consolidation equations are then solved with the aid of the proposed FE model. In this analysis, the seabed behaviour is assumed to be linear elastic with the soil strains remaining small. The influence of wave obliquity on seabed responses, i.e. the pore pressure and soil stresses, are then studied. It is revealed that three-dimensional characteristics systematically affect the distribution of soil response around the circumference of the underwater pipeline. Numerical results suggest that the effect of wave obliquity on soil responses can be explained through the following two mechanisms: (i) geometry-based three-dimensional influences, and (ii) the formation of inversion nodes. Further, a parametric study is carried out to investigate the influence of soil, wave and pipeline properties on wave-associated pore pressure as well as principal effective and shear stresses within the porous bed, with the aid of proposed three-dimensional model. There is strong evidence in the literature that the failure of marine pipelines often stems from the instability of seabed soil close to this structure, rather than from construction deficiencies. The wave-induced seabed instability is either associated with the soil shear failure or the seabed liquefaction. Therefore, the developed three-dimensional FE model is used in this thesis to further investigate the instability of seabed soil in the presence of a pipeline. The widely-accepted criterion, which links the soil liquefaction to the wave-induced excess pressure is used herein to justify the seabed liquefaction. It should be pointed out that although the present analysis is only concerned with the momentary liquefaction of seabed soil, this study forms the basis for the three-dimensional analysis of liquefaction due to the residual mechanisms. The latter can be an important subject for future investigations. At the same time, a new concept is developed in this thesis to apply the dynamic component of soil stress angle to address the phenomenon of wave-associated soil shear failure. At this point, the influence of three-dimensionality on the potentials for seabed liquefaction and shear failure around the pipeline is investigated. Numerical simulations reveal that the wave obliquity may not notably affect the risk of liquefaction near the underwater pipeline. But, it significantly influences the potential for soil shear failure. Finally, the thesis proceeds to a parametric study on effects of wave, soil and pipeline characteristics on excess pore pressure and stress angle in the vicinity of the structure.
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Chen, Bao-Ching, and 陳保慶. "The study on resistance liquefaction threshold and liquefaction potential assessment in on-site seabed soil." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/38238597636762941218.
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碩士<br>國立臺灣海洋大學<br>河海工程學系<br>100<br>In this study, the Kaohsiung Harbor Intercontinental Container Center for the study area with seismic and ocean wave conditions to explore. The testing sample to the center of the coast of Kaohsiung Intercontinental Container depth 23.5m drilling soil sample-based and seismic force cycle measured wave data to be tested in order to understand the sea-bed soil stability under seismic and wave action. In order to understand the different external force to the sea bed soil strength changes in the real situation, this study uses the seabed soil test and use the water rainstorm drop way for the production of specimens to simulate the deposition arranged in the case of sea-bed soil depth z = 3 m . In this study, cyclic triaxial analog seismic forces and wave forces, combined with the torsional shear stress test, the Research and Analysis of pore water pressure to stimulate the situation now to the seabed soil liquefaction resistance threshold, and the establishment of the liquefaction potential assessment methods of this study.
This study investigates the use of Stoke's second-order wave theory calculation from wave pressure, triaxial axial combination of the torsional shear stress test (simulation of wave forces combined with the torsional shear stress); and the use of cycle 1 second under the conditions in the period of 12 seconds three-axis axial test (simulated seismic forces). By the different test results analysis to investigate the pore water pressure to stimulate the behavior, the existing soil liquefaction resistance threshold, as well as its assessment of soil liquefaction potential.
The combination of torsional shear test results by the seismic forces and wave forces, Seed (1976) and Chang (2004) pore water pressure excitation mode of, in different experimental Seed (1976) may be more effective prediction of pore water pressure. Under different external test due to previous not consider the influence exerted by the torsional shear stress, pore water pressure is to stimulate the first two forecasting models have obvious gap. Liquefaction damage occurs by the liquefaction resistance curve can be learned under the same role in the number, relative to the seismic force, wave force requires a long time. This study suggests that the seismic force can be repeatedly the role of the number Nc is = 100 (times) when the now to the sea bed, anti-liquefaction threshold value of about 0.19; wave forces repeated the role of time of 1200 seconds when the now to the sea bed, anti-liquefaction threshold value of about 0.20 as Kaohsiung waters, the seabed liquefaction resistance threshold. In this study, the Construction and Planning Agency building the basis of structural design specifications Seed et al (1971) simplified method and harbor structures design criteria (2005) to estimate the force of the earthquake, it is recommended that the ground acceleration Amax halved, the theoretical assessment of the results of the research trials liquefaction damage the results of the comparison are obtained with this study, test results are the same. In this study, Chen and Yang (1996) assessment methods, and draw the depth of the seabed under wave action soil shear stress diagram, obtained here for the greatest possible depth of liquefaction beneath the surface of the sea-bed 4.57m, and the establishment of the seabed soil liquefaction potential assessment methods to assess the depth of the seabed by the wave force under the seabed liquefaction damage may occur.
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Tsai, Pei-Chi, and 蔡培祺. "The study of Probability Model of Wave induced Seabed Sand Liquefaction." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/98273076731137806756.
Full textAbstract:
碩士<br>國立臺灣海洋大學<br>河海工程學系<br>97<br>In recent years climate change caused by unusual sea-level elevation and increasing the frequency of typhoons, it threatens the safety of marine construction projects. The past studies of seabed liquefaction potential are mostly related to a deterministic analysis. When the main considering wave force is greater than the sea-bed sand soil, the sea-bed soil liquefaction occurred. On the contrary will not be liquefied, however, in this case the sea-bed of sand liquefaction is still possible. In order to understand the role of a variety of sea bed wave power of the statistical characteristics of liquefaction, this study was adopted by the Land Application of reliability analysis to assess the probability of soil liquefaction process, combined with statistics on the log-normal distribution to establishment of wave induced sea-bed sand liquefaction probability model.
In this study, the wave height’s random characteristic on behalf of the variability of wave induced cyclic shear stress is used. Based on dynamic test of sea-bed liquefaction analysis of sea-bed sand soil liquefaction resistance, the difference of wave force between theory value and Hydraulic model test is also discussed. By the statistical analysis of results showed that the same conditions and test results into the Land of the assessment formula, it found that about 50% to 80% of the difference in coefficient of variability of sea-bed of sand is smaller than Land assessment formula. To explore the main reason is that most laboratories that may be liquefied sand seabed conditions tested, thus the scope of information resulting in smaller differences.
On the hand, comparing the past to evaluate the potential of sea-bed liquefaction and liquefaction probability of difference represented by the reason, related researchers are in the past as a small wave amplitude theory outside the main consideration, so the main reason for the sea-bed soil liquefaction resistance different than the definition. In addition to the relative density, soil depth and wave period can also cause to the consideration of differences in the causes of liquefaction probability. Finally, this study using the 『Tai Tam Taichung Harbor to the laying of gas pipeline』case analysis found that the path of buried pipeline, the segment off the coast of Hsinchu, Miaoli near Taichung Harbor and coastal waters there have a higher probability of liquefaction. According to the design return cycle of the 50-year assessment of the typhoon wave conditions, in Shanghai pipeline path between bed sand liquefaction rate of 7.24% ~ 13.89%.
In this study, try to apply wave analysis and dynamic test results to establishment of wave induced sea-bed sand liquefaction probability model. Combined with the specific wave parameters by statistical probability could be obtained the liquefaction probability of sea-bed sand. In the future, it could be supported by risk assessment analysis, will be able to help to ensure the safety assessment of the marine engineer.
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SAINTPREUX, Stanley, and 史瑋帆. "Soil liquefaction potential of seabed near Chang-Hua area in Taiwan." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/w6yxh8.
Full textBook chapters on the topic "Seabed liquefaction"
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Jeng, Dong-Sheng. "Wave-Induced Progressive Liquefaction in a Porous Seabed." In Porous Models for Wave-seabed Interactions. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-33593-8_10.
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Cha, Daeho, Michael Blumenstein, Hong Zhang, and Dong-Sheng Jeng. "A Neural-Genetic Technique for Coastal Engineering: Determining Wave-induced Seabed Liquefaction Depth." In Engineering Evolutionary Intelligent Systems. Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-75396-4_12.
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Fang, Di, Weiyun Chen, and Guoxing Chen. "Effects of Soil Cross-Anisotropy on the Wave-Induced Residual Liquefaction Around an Immersed Tunnel in the Liquefiable Seabed." In Proceedings of GeoShanghai 2018 International Conference: Tunnelling and Underground Construction. Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-0017-2_24.
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Yincan et al, Ye. "Seabed Sand Liquefaction and Evaluation." In Marine Geo-Hazards in China. Elsevier, 2017. http://dx.doi.org/10.1016/b978-0-12-812726-1.00009-7.
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Jeng, Dong-Sheng. "Porous Models for Wave-induced Seabed Liquefaction." In Handbook of Coastal and Ocean Engineering. WORLD SCIENTIFIC, 2017. http://dx.doi.org/10.1142/9789813204027_0034.
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Teh, T., A. Palmer, and M. Bolton. "Wave-induced seabed liquefaction and the stability of marine pipelines." In Cyclic Behaviour of Soils and Liquefaction Phenomena. Taylor & Francis, 2004. http://dx.doi.org/10.1201/9781439833452.ch54.
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Vu, Bathao, Yonglai Zheng, and Jiayu Zhong. "Experimental study on wave-induced liquefaction in sandy silt seabed." In Geomechanics and Geotechnics. CRC Press, 2010. http://dx.doi.org/10.1201/b10528-60.
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Bonjean, D., P. Foray, and H. Michallet. "Occurrence of liquefaction in cyclic burial of a structure submitted towave-actions and resting on the seabed." In Cyclic Behaviour of Soils and Liquefaction Phenomena. Taylor & Francis, 2004. http://dx.doi.org/10.1201/9781439833452.ch47.
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Zhang, H., and D. Jeng. "Numerical modeling for breaking wave-induced momentary liquefaction in a porous seabed." In Hydrodynamics VI: Theory and Applications. Taylor & Francis, 2004. http://dx.doi.org/10.1201/b16815-50.
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Ye, Guanlin, Dong-sheng Jeng, Song Cui, and Jian Leng. "Liquefaction of a poro-elastoplastic seabed under combined wave and current loading." In Computer Methods and Recent Advances in Geomechanics. CRC Press, 2014. http://dx.doi.org/10.1201/b17435-324.
Full textConference papers on the topic "Seabed liquefaction"
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Windt, C., N. Goseberg, S. Schimmels, et al. "Numerical Modelling of Liquefaction Around Marine Structures - Progress and Recent Developments." In ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/omae2022-79821.
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Abstract The liquefaction around marine structures can lead to severe structural failure and the susceptibility of seabed soil to liquefaction at a specific installation site of, e.g., floating offshore wind turbines should be included within the design process and site evaluation. To that end, advanced prediction tools based on numerical modelling can provide valuable insight into the hydro-geotechnical processes. However, due to the complex interaction of the underlying physics, developing a holistic modelling framework for seabed liquefaction is a challenging task. The NuLIMAS research project (Numerical modelling of seabed liquefaction around marine structures) aims at the development of such a numerical model of seabed liquefaction implemented in the OpenFOAM® framework. This paper provides an overview of the NuLIMAS project, laying out the current state of the art of experimental and numerical modelling approaches for seabed liquefaction and presenting some initial results.
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Sui, Titi, Jisheng Zhang, Jinhai Zheng, and Chi Zhang. "Modeling of Wave-Induced Seabed Response and Liquefaction Potential Around Pile Foundation." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-10230.
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A 3D integrated model is developed to study wave-induced seabed response and liquefaction potential around square pile foundation. While a Boussinesq wave mode (FUNWAVE) is used to simulate the wave-pile interaction, a seabed mode (WINBED) based on Biot’s poro-elastic theory is solved for the seabed deformation, effective stresses and pore water pressure in soil. After verified with previous model and experimental works, this integrated model is applied to investigate the wave-induced seabed response and liquefaction potential in the vicinity of square pile foundation. The numerical results indicate that wave-induced pore pressure reduces rapidly with an increasing seabed depth, and the maximum pore pressure and largest liquefaction potential can be identified in front of the square pile foundation. It is also found that the phenomenon of liquefaction may occur inside the seabed soil while the upper layer remains un-liquefied.
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Tomi, Yuichiro, Kouki Zen, Guangqi Chen, Kiyonobu Kasama, and Yuichi Yahiro. "Effect of Relative Density on the Wave-Induced Liquefaction in Seabed Around a Breakwater." In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79601.
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The liquefaction of seabed induced by ocean waves is considered to be one of the influential phenomena related to damages of coastal marine structures such as the floating of pipelines, the settlement of concrete blocks and the reduction of pile foundation resistance, etc, since the liquefied seabed loses its shear strength and then easily and drastically deforms. A model flume was newly developed to simulate the wave-induced liquefaction in seabed around a breakwater with a reduced model scale against the caisson type breakwater widely used in Japan. The dimension of developed flume was the length of 6.0m, the width of 0.4m and the depth of 0.9m. As for geotechnical parameters affecting the wave-induced liquefaction of seabed around the model breakwater, the effect of seabed density on liquefaction was highlighted in this paper in terms of the generation of pore water pressure in seabed and the settlement of seabed surface. The experiment was carried out under the following conditions; the wave period was 1.0s, the incident wave height was 55mm, the depth of water was 170mm, the thickness of permeable layer was 350mm and the relative density was between 20% and 60%. In order to satisfy similarity law in 1g gravitational field, the polymer fluid was used to decrease the permeability of model seabed. As the result from this study, the following conclusions were obtained; 1) When water was used as a fluid, the liquefaction due to the residual excess pore water pressure happened in the sand bed with the relative density of 23%. However, the liquefaction did not happened in the sand bed with the relative density more than 30%, 2) When the polymer fluid is used for reducing the permeability of model seabed, the generation of pore water pressure ratio becomes larger and the dissipation time of generated pore pressure becomes longer compared with the case using water, 3) When the relative density of seabed was between 20% and 40%, the liquefaction induced by the residual excess pore water pressure was observed in the deep area of model seabed while the shear failure of seabed was observed in the shallow area of model seabed, 4) When the relative density was between 50% and 60%, the liquefaction due to the residual excess pore water pressure was not observed in the present experimental conditions.
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Yang, Li-Jing, Chang-Fei Li, Jun-Qin Wang, and Fu-Ping Gao. "Combined Wave-Current Induced Instantaneous Liquefaction of a Sandy Seabed." In ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-96655.
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Abstract Accurate prediction for the liquefaction depth of a porous seabed is crucial to the design of shallow foundations; nevertheless most previous studies are predominantly limited to wave-only conditions. In this study, the combined wave-current induced instantaneous liquefaction of a sandy seabed is investigated analytically. The explicit expression of liquefaction depth under combined wave-current loading condition is derived, which can converge to that under the linear wave condition when the current velocity approaches zero. Parametric study indicates that the effects of imposing a current onto progressive waves on the distribution of excess pore pressures and the corresponding liquefaction depth are unneglectable, especially for the opposite current conditions.
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Shanmugasundaram, Ranjith Khumar, Henrik Rusche, Christian Windt, V. S. Özgür Kirca, B. Mutlu Sumer, and Nils Goseberg. "Numerical Modelling of Residual Liquefaction in the Subsoil Under a Vibrating Plate." In ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/omae2022-79025.
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Abstract Seabed liquefaction is the phenomenon by which the seabed soil loses its strength and stiffness, due to applied stress, and behaves like a non-Newtonian fluid. Seabed liquefaction can lead to severe failure of marine structures, such as buried pipelines or coastal breakwaters. Numerical modelling of liquefaction can provide valuable insights into the prevailing wave-structure-soil interaction. However, the holistic modelling of seabed liquefaction, including the transition from solid to liquid and back to solid soil, is challenging, due to the prevailing hydrogeotechnical processes. As a step towards the development of such a holistic numerical model of seabed liquefaction, this paper considers the modelling of the soil under a rocking plate as an idealised representation of a caisson breakwater as presented in [1]. The numerical model has recently been presented in [2] and includes equations for the accumulation of pore pressure and a criterion to distinguish between the liquefied and non-liquefied regions. The numerical results are compared to the experimental results taken from [1]. Different numerical model setups are presented to overcome modelling challenges due to occurring punching shear failure.
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Qiu, Yingqing, and H. Benjamin Mason. "Numerical Experiments of Seabed Liquefaction during Ocean Wave Loading." In Geo-Congress 2020. American Society of Civil Engineers, 2020. http://dx.doi.org/10.1061/9780784482810.076.
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Ou, Jianhua, Dong-Sheng Jeng, Andrew Chan, and Pui-Lee Vun. "Wave-Induced Liquefaction Around Breakwater Heads." In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79019.
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In this paper, a poro-elastoplastic model (PORO-WSSI II) is proposed to prediction of wave-induced liquefaction around breakwater heads. Existing models for the wave-induced seabed response around breakwater heads have been limited to poro-elastic soil behaviour and de-coupled oscillatory and residual mechanisms for the rise in excess pore water pressure. The proposed model was reduced to special cases and verified with existing 2D experimental data available and 3D analytical solution in front of a breakwater. With the proposed new model, a parametric study is conducted to investigate the relative differences of the predictions of the wave-induced pore pressure and liquefaction with poro-elastic and poro-elasto-plastic models. With the new model, we further investigate the wave-induced liquefaction in a layered seabed around breakwater heads.
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Yu, Yueqian, Guohui Xu, Xin Wang, Huixin Liu, and Qingpeng Zhao. "Experimental Study on Influences of Wave Height on Liquefaction Depth of Silty Soil Bed." In ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-20770.
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Storm waves tend to cause seabed liquefaction by exerting strong cyclic loads on the seabed of the Yellow River Delta. In order to study influences of different wave heights on liquefaction depth of the soil bed, silty soil taken from the Yellow River Delta is used to prepare a soil bed for flume experiments and local parts of superficial soil layer were disturbed by hand. The weakened soil tended to liquefy and slide under wave actions and the liquefaction depth increased with the increasing of wave height. Based on the experimental results, an empirical relationship was proposed between liquefaction depth of silty soil bed and wave height under experimental conditions.
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Zhou, Xiang-Lian, Jian-Hua Wang, and Yun-Feng Xu. "An Analytical Solution for Wave-Induced Soil Response and Seabed Liquefaction." In ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-21182.
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In this study, an analytical method to solve the wave-induced pore pressure and effective stress in a saturated porous seabed is proposed. The seabed is considered as a saturated porous medium and characterized by Biot’s theory. The displacements of the solid skeleton and pore pressure are expressed in terms of two scalar potentials and one vector potential. Then, the Biot’s dynamic equations can be solved by using the Fourier transformation and reducing to Helmholtz equations that the potentials satisfy. The general solutions for the potentials are derived through the Fourier transformation with respect to the horizontal coordinate. Numerical results show that the permeability and shear modulus of the porous seabed has obvious influence on the response of the seabed. The vertical effective stress and attenuation velocity of pore pressure along seabed depth increase as permeability k increases. The liquefaction may be occur at the surface of seabed when shear modulus decreasing.
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SAKAI, Tetsuo, Hitoshi GOTOH, Eiji HARADA, and Yasufumi IMOTO. "Subsidence of Rubble Stones due to Wave-Induced Seabed Liquefaction." In Proceedings of the 2nd International Conference. WORLD SCIENTIFIC, 2004. http://dx.doi.org/10.1142/9789812703040_0087.
Full textReports on the topic "Seabed liquefaction"
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Nogami, Toyoaki, Ganeswara R. Dasari, and Pengzhi Lin. Wave-induced Mine Burial into Seabed; Part 1: Cohesionless Seabed in Cyclic Liquefaction State. Defense Technical Information Center, 2001. http://dx.doi.org/10.21236/ada625902.
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