Wave pressures and uplift forces on and scour around submarine pipeline in clayey soil
TL;DR: In this article, the authors investigated wave-induced pressures and uplift forces on a submarine pipeline (exposed, half buried and fully buried) in clayey soil of different consistency index both in regular and random waves.
About: This article is published in Ocean Engineering.The article was published on 2003-02-01. It has received 25 citations till now. The article focuses on the topics: Submarine pipeline & Pore water pressure.
Citations
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TL;DR: In this paper, a series of multiphase flow (slide material and the ambient seawater) numerical simulations using a computational fluid dynamics (CFD) approach aimed at investigating the vertical forces during submarine slide flow around a pipeline at different gap ratios (pipeline-seabed gap normalized by pipeline diameter) from 0.08 to 10.
7 citations
TL;DR: In this article, the particle trajectory of liquefied soil is observed to be elliptical under the condition of small-amplitude waves in shallow water by wave flume tests.
5 citations
TL;DR: In this article, the wave force variation due to burial depends on the engineering characteristics of the sub-soil like hydraulic conductivity and porosity, apart from the design environmental conditions.
Abstract: Submarine pipelines encounter significant wave forces in shallow coastal waters due to the
action of waves. In order to reduce such forces (also to protect the pipe against anchors and dropped objects)
they are buried below the seabed. The wave force variation due to burial depends on the engineering
characteristics of the sub soil like hydraulic conductivity and porosity, apart from the design environmental
conditions. For a given wave condition, in certain type of soil, the wave force can reduce drastically with
increased burial and in certain other type of soil, it may not. It is hence essential to understand how the wave
forces vary in soils of different hydraulic conductivity. Based on physical model study, the wave forces on
the buried pipeline model is assessed for a wide range of wave conditions, for different burial depths and for
four types of cohesion-less soils, covering hydraulic conductivity in the range of 0.286 to 1.84 mm/s. It is
found that for all the four soil types, the horizontal wave force reduces with increase in depth of burial,
whereas the vertical force is high for half buried condition. Among the soils, well graded one is better for
half buried case, since the least vertical force is experienced for this situation. It is found that uniformly
graded and low hydraulic conductivity soil attracts the maximum vertical force for half buried case. A case
study analysis is carried out and is reported. The results of this study are useful for submarine buried pipeline
design.
4 citations
TL;DR: In this paper, physical model investigations were carried out in a wave flume to assess the change in the horizontal and vertical hydrodynamic forces on a submarine pipeline for different depths of burial.
Abstract: Information on wave force variation due to different burial of submarine pipeline is essential in order to choose its appropriate depth of burial. It is a function of wave climate, water depth, geotechnical and hydraulic properties of the seabed soil, etc. To solve this problem, physical model investigations were carried out in a wave flume to assess the change in the horizontal and vertical hydrodynamic forces on a submarine pipeline for different depths of burial. The marine sand is well graded and has hydraulic conductivity of 1.84 mm/s. It is found that the horizontal force reduces nonlinearly with increase in depth of burial. 75% of the magnitude of the horizontal force reduces by just burying the pipe, when compared to the horizontal force on the pipeline placed on the seabed. The vertical hydrodynamic force is smaller for half buried pipe and increases for just fully buried case due to the significant change in the magnitude as well as the phase difference between the pore water dynamic pressures. ...
4 citations
TL;DR: In this paper, the wave force variation for different buried conditions of the pipeline depends on the wave height, wave period, water depth, engineering and hydraulic properties of the seabed soil, like hydraulic conductivity, porosity, and submerged soil density.
4 citations
References
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TL;DR: In this article, the authors investigated the relationship between the erosional properties of combined mud and sand sediments, and found that adding sand to mud, or vice versa, increases the erosion resistance and reduces the erosion rates when the critical shear stress for erosion is exceeded.
500 citations
TL;DR: The effect of leewake of the pipe is the key element in the scour process, and it is demoed in this article, where the results of an experimental investigation on scour below pipelines exposed to waves.
Abstract: This paper presents the results of an experimental investigation on scour below pipelines exposed to waves. The effect of leewake of the pipe is the key element in the scour process, and it is demo...
164 citations
TL;DR: In this paper, the initiation of motion of consolidated cohesive sediments under a unidirectional flow of clear water was studied in a flume-tunnel capable of providing a bed shear stress up to 26 Pa and a velocity of 3.5 m/s, 3 mm above the bed.
Abstract: The initiation of motion of consolidated cohesive sediments under a unidirectional flow of clear water was studied. Experiments were performed in a flume‐tunnel capable of providing a bed shear stress up to 26 Pa and a velocity of 3.5 m/s, 3 mm above the bed. Samples were prepared in a specially designed press using a carefully controlled consolidation procedure. Critical shear stress and velocity were found to increase with compressive strength, vane shear strength, plasticity index, clay content, and consolidation pressure.
151 citations
TL;DR: The water wave induced seepage force on a pipeline buried in the seabed is investigated in this paper, where the pipeline is assumed to be rigid and not supported by any anchoring force.
105 citations
TL;DR: In this paper, a finite element simulation of the wave-induced hydrodynamic uplift force acting on a submarine pipeline buried in sandy seabed sediments subject to continuous loading of sinusoidal surface waves is presented.
64 citations