scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Study of Scour around Submarine Pipeline with a Rubber Plate or Rigid Spoiler in Wave Conditions

01 Nov 2012-Journal of Waterway Port Coastal and Ocean Engineering-asce (American Society of Civil Engineers (ASCE))-Vol. 138, Iss: 6, pp 484-490
TL;DR: In this article, a flexible rubber plate was placed between the submarine pipeline and bed, while the rigid spoiler was attached to the top of the pipe to enhance the scour depth and extent.
Abstract: This paper presents results from laboratory experimental model studies investigating scour by waves around a pipeline attached to a flexible rubber plate or rigid spoiler. The rubber plate was placed between the submarine pipeline and bed, while the rigid spoiler is attached to the top of the pipe. The scour around pipelines with and without a rubber plate or a rigid spoiler under regular and irregular waves was observed and measured for a range of pipe sizes, wave amplitudes and frequencies, and the length of the plate/height of the spoiler. The experiments reveal that although the rigid spoilers can enhance the scour depth and extent (thus accelerating the self-burial of the pipe), they also have significant influence on both the upstream and downstream bed topography as sand ripples and dunes are formed. On the other hand, the rubber plates cannot only significantly increase the scour depth but also have little effect on the upstream and downstream bed. The experiments show that when the length of the plate is about 1.5 times the pipe size, it provides the optimum performance in terms of the largest scour depth while restricting the impact on nearby beds for the parameters investigated in this study.
Citations
More filters
Journal ArticleDOI
TL;DR: In this article, an integrated Finite Element Method (FEM) model is proposed to investigate the dynamic seabed response for several specific pipeline layouts and to simulate the pipeline stability under waves loading.

73 citations

Journal ArticleDOI
TL;DR: In this article, a series of comprehensive laboratory experiments are carried out in a wave flume to investigate the wave-induced pore pressures around a partially embedded pipeline in a trench layer.

39 citations

Journal ArticleDOI
15 Jul 2014
TL;DR: In this article, a review of the environmental considerations, including potential ecological impacts, associated with subseabed geological storage of CO2 is presented, which will benefit national programs and industry and will be valuable to researchers in a broad range of disciplines.
Abstract: Many countries are now using or investigating offshore geological storage of CO2 as a means to reduce atmospheric CO2 emissions. Although associated research often focuses on deep-basin geology (e.g. seismic, geomagnetics), environmental data on the seabed and shallow subseabed is also crucial to (1) detect and characterise potential indicators of fluid seeps and their potential connectivity to targeted storage reserves, (2) obtain baseline environmental data for use in future monitoring, and (3) acquire information to facilitate an improved understanding of ecosystem processes for use in impact prediction. This study reviews the environmental considerations, including potential ecological impacts, associated with subseabed geological storage of CO2. Due to natural variations in CO2 levels in seafloor sediments, baseline CO2 measurements and knowledge of physical–chemical processes affecting the regional distribution of CO2 and pH are critical for the design of appropriate monitoring strategies to assess potential impacts of CO2 seepage from subseabed storage reservoirs. Surficial geological and geophysical information, such as that acquired from multibeam sonar and sub-bottom profiling, can be used to investigate the connectivity between the deep reservoirs and the surface, which is essential in establishing the reservoir containment properties. CO2 leakage can have a pronounced effect on sediments and rocks which in turn can have carryover effects to biogeochemical cycles. The effects of elevated CO2 on marine organisms are variable and species-specific but can also have cascading effects on communities and ecosystems, with marine benthic communities at some natural analogue sites (e.g. volcanic vents) showing decreased diversity, biomass, and trophic complexity. Despite their potential applications, environmental surveys and data are still not a standard and integral part of subseabed CO2 storage projects. However, the habitat mapping and seabed characterisation methodology that underpins such surveys is well developed and has a strong record of providing information to industry and decision makers. This review provides recommendations for an integrated and interdisciplinary approach to offshore geological storage of CO2, which will benefit national programs and industry and will be valuable to researchers in a broad range of disciplines.

38 citations

Journal ArticleDOI
TL;DR: In this article, the multivariate adaptive regression splines (MARS) technique was applied to estimate scour depth around pipelines and a gamma test was used to define the most effective parameters on scouring phenomena below pipelines.
Abstract: In this study, the multivariate adaptive regression splines (MARS) technique was applied to estimate scour depth around pipelines. To this purpose, 90 data sets related to effective dimensionless parameters on pipeline scouring phenomena were gathered from literature. A gamma test (GT) was used to define the most-effective parameters on scouring phenomena below pipelines. Performance of MARS model was compared with multilayer perceptron (MLP) neural network and empirical formulas. Results of the GT showed that e/D, τ*, and y/D are the most important parameters for scour depth. Results of MARS model with coefficient of determination (0.91) and root-mean square error (0.05) indicated that this model has suitable performance for predicting scour depth under pipelines and results of this model are more accurate compared to empirical formulas. Comparing results of MARS model and MLP showed that accuracy of MARS model is slightly lower than that of the MLP.

27 citations


Cites background from "Study of Scour around Submarine Pip..."

  • ...Maximum depth of scour happens when the interaction of the flow, pipeline, and river bed materials reach equilibrium (Cao et al. 2015; Yang et al. 2012)....

    [...]

  • ...Therefore, investigators have studied this phenomenon using experimental and numerical approaches (Çevik and Yüksel 1999; Yang et al. 2012; Yasa 2011)....

    [...]

Journal ArticleDOI
TL;DR: In this article, the authors investigated the protection of scour around submarine pipelines under unidirectional flow using a rubber plate placed underneath the pipes and showed that there exists a critical pressure difference over which the movement of sediment and scour takes place.

27 citations

References
More filters
Book
01 Jan 2002
TL;DR: Scour Below Pipelines Scour around a single slender pile Scour Around a Group of Slender Piles Examples of More Complex Configurations ScourAround Large Piles Scouraround Breakwaters Scour at Seawalls Ship-Propeller Scour Impact of Liquefaction
Abstract: Scour Below Pipelines Scour Around a Single Slender Pile Scour Around a Group of Slender Piles Examples of More Complex Configurations Scour Around Large Piles Scour Around Breakwaters Scour at Seawalls Ship-Propeller Scour Impact of Liquefaction.

749 citations

Journal ArticleDOI
TL;DR: The results of the European Union Marine Science and Technology (EU MAST) III project "Scour Around Coastal Structures" (SCARCOST) as mentioned in this paper were summarized under three headings.

201 citations

Journal ArticleDOI
TL;DR: In this article, an experimental study on the onset of scour below and self-burial of pipelines in currents/waves was conducted, where pressure was measured on the surface of a slightly buried pipe at two points, one at the upstream side and the other at the downstream side of the pipe, both in the sand bed.

189 citations

Journal ArticleDOI
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

Journal ArticleDOI
TL;DR: In this paper, it was shown that the critical hydraulic gradient associated with the initiation of scour is equal to the flotation gradient of the bed sediment and the pressure drop between the stagnation pressure upstream and wake pressure downstream of the pipe induces this hydraulic gradient.
Abstract: The primary objective of this study is to improve understanding of the mechanism causing scour in unidirectional current. Experiments have shown how local scour develops around submarine pipelines in noncohesive sediments. The study shows that piping is the dominant cause of the initiation of scour. Piping and the stagnation eddy combine to undermine the pipeline, and mark the onset of scour. The critical hydraulic gradient associated with the initiation of scour is equal to the flotation gradient of the bed sediment. The pressure drop between the stagnation pressure upstream and wake pressure downstream of the pipe induces this hydraulic gradient. When a pipe is just embedded, the onset of scour does not occur if the ratio of the flow depth to pipe diameter exceeds 3.5. Similarly, the onset of scour does not occur for half‐buried pipes. The reduction in pressure gradient across the pipeline for these flow/pipe combinations accounts for the lack of scour. The onset of scour can be prevented by placing an ...

152 citations