Experimental study of soil responses around a pipeline in a sandy seabed under wave-current load

Chen, Hao; Zhang, Jisheng; Tong, Linlong; Sun, Ke; Guo, Yakun; Wei, Chao

doi:10.1016/j.apor.2022.103409

Cited by 13 publications

(5 citation statements)

References 30 publications

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“…The third model validation compares the present model with the experimental results of Chen et al [30]. As shown in Figure 14, four pore pressure sensors were installed in the seabed to measure the pore pressure around the pipeline and below the pipeline for 3 cm (P5), 8 cm (P6), and 18 cm (P7).…”

Section: Validation No 3: a Single Pipeline In The Trench Layermentioning

confidence: 84%

“…Validation no. 3: Comparison of the experimental results between the present model and Chen et al [30] for a single pipe with a trench layer; in this experiment, in addition to the pore pressures along the pipeline surface, additional measurements of pore pressures below the pipeline were taken. The first model validation is to compare the numerical results obtained by the present two-way coupling model with the experimental results of Sun et al [29].…”

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confidence: 87%

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Assessment of Wave–Current-Induced Liquefaction under Twin Pipelines Using the Coupling Model

Zhang

Cui

Zhai

et al. 2023

JMSE

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Although twin pipelines in series have been used to transport hydrocarbons in engineering practice, most previous studies focused on the dynamic response of the seabed around a single pipeline. A two-way coupling model of fluid–structure–seabed interaction (FSSI) is proposed for the study of the soil response and liquefaction caused by waves and currents around twin pipelines. The present model integrates the flow model and the seabed model by introducing a boundary condition of velocity continuity in addition to the continuity of pressures at the seabed surface. Then, the inconsistency between the physical process and numerical simulation can be overcome in the one-way coupling model. Through a series of numerical simulations, the influence of different flow characteristics, soil properties, and pipeline configurations on the seabed response under the two-way coupling process were explored, and compared with the results of the single pipeline. The numerical results indicate that the twin pipeline configuration significantly alters the relevant responses compared to the single pipeline configuration, including the after-consolidation state, amplitude of velocity at the seabed surface, and distribution of pore pressure in the seabed. The parametric studies show that the amplitudes of the wave and current have significant impacts on the distribution of pore pressure in the seabed. The pore pressure in the seabed increases with the increase of forward wave current, while the results of reverse wave current are the opposite. In addition, the liquefaction range around the pipeline increases with the increase of Hw and Tw, and increases with the decrease of Sr and ks. At the same time, the gaps (G) and the ratio of pipe radius (R1/R2) between the twin pipelines also significantly affect the seabed response and liquefaction distribution around the pipeline.

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Section: Validation No 3: a Single Pipeline In The Trench Layermentioning

confidence: 84%

mentioning

confidence: 87%

Assessment of Wave–Current-Induced Liquefaction under Twin Pipelines Using the Coupling Model

Zhang

Cui

Zhai

et al. 2023

JMSE

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“…For the case of a pure seabed without a structure, several analytical solutions have been developed under various conditions [12][13][14][15]. However, for a seabed including structures such as submarine pipelines [16][17][18][19][20][21][22][23][24][25][26], breakwaters [27][28][29], coastal slopes [30], offshore wind turbine foundations [31][32][33][34][35][36][37], gravity-based structure (GBS) offshore platforms [38], dumbbell-shaped cofferdams [39], and immersed tunnels [40,41], the presence of the structures complicates the boundary conditions, generally requiring numerical methods for analyses. Recently, Li et al [42] developed an open-source numerical toolbox for simulating the interaction between a porous seabed, waves, and structures.…”

Section: Introductionmentioning

confidence: 99%

Wave-Induced Instantaneous Liquefaction of a Non-Cohesive Seabed around Buried Pipelines: A Liquefaction-Associated Non-Darcy Flow Model Approach

Han,

Zhou,

Zhang

et al. 2024

JMSE

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In complex marine environments, the wave-induced instantaneous liquefaction of the seabed is a key issue for the long-term safety control of marine structures. Existing computational frameworks for instantaneous liquefaction result in unreasonable tensile stresses in a non-cohesive seabed. To address this issue, a liquefaction-associated non-Darcy flow model has been proposed, but it has only been applied to the scenario of a pure seabed without a structure. In this study, we applied the previously proposed non-Darcy flow model to investigate the mechanism of wave–seabed–structure interactions under extreme wave loading considering a pipeline fully buried in a non-cohesive seabed. By comparing the liquefaction depths in the presence and absence of structures, it was found that the existence of structures weakens the attenuation of the pore pressure amplitude and influences the overall pore pressure distribution. Parametric studies were conducted. It was found that the liquefaction depth from the non-Darcy model is approximately 0.73 times that from the traditional Darcy model, regardless of whether or not a pipeline is involved. A quantitative relationship between the wave loading and structural size was established. The liquefied zone above the buried pipeline was found to be smaller than that in a pure seabed without a structure. A tentative explanation is provided for this phenomenon.

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“…Based on the literature review above, studies treating the sandy seabed as an elastoplastic material remain very limited at present, because the oscillatory response can be described accurately, while the residual pore pressure cannot be captured. In addition to numerical analysis, both oscillatory mechanism and residual liquefaction have been observed in laboratory experiments [11][12][13]. The wave flume test is a common method that can intuitively simulate wave conditions.…”

Section: Introductionmentioning

confidence: 99%

Fully Buried Pipeline Floatation in Poro-Elastoplastic Seabed under Combined Wave and Current Loadings

Leng,

Liu,

Liao

et al. 2024

JMSE

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The floatation capacity of seabed pipelines has long been considered a key risk element during design, especially with the combined loading of waves and currents. This paper presents a two-dimensional coupled approach with a poro-elastoplastic theory to study the floatation of pipelines with the combined loading of waves and currents. The findings suggest that the proposed method is able to capture the mechanical performance of pipeline floatation. Pipeline floatation occurs in two distinct phases. In the initial phases, the pipelines float slowly with the cyclic loadings. In the second stage, when the backfill soil in the middle position of the pipelines begins to liquefy, the floating displacement increases obviously. The boundary constraints provided by the pipelines strengthen the backfill soil as well as accelerate the release of excessive pore water pressure. Meanwhile, a nonliquefiable region is formed under the pipelines. The floating displacement of the pipelines increases as well as current velocity, wave height, and wave period, and reduces with increased backfill soil permeability. Increasing the permeability coefficient of backfill soil can obviously restrain the floatation of pipelines.

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Experimental study of soil responses around a pipeline in a sandy seabed under wave-current load

Cited by 13 publications

References 30 publications

Assessment of Wave–Current-Induced Liquefaction under Twin Pipelines Using the Coupling Model

Assessment of Wave–Current-Induced Liquefaction under Twin Pipelines Using the Coupling Model

Wave-Induced Instantaneous Liquefaction of a Non-Cohesive Seabed around Buried Pipelines: A Liquefaction-Associated Non-Darcy Flow Model Approach

Fully Buried Pipeline Floatation in Poro-Elastoplastic Seabed under Combined Wave and Current Loadings

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