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Proceedings Article•DOI•

Measurement of sea bed scour around a pile-simplified instrumentation

M. Ram Babu1, V. Sunder, S. Narasimha Rao•
Indian Institute of Technology Madras1
15 Apr 1998-pp 334-339

TL;DR: In this paper, a simplified experimental technique for the measurement of scour around pile foundation in laboratories is presented, where a suitable instrumentation system has been developed and adopted for measuring scour depth with time till the equilibrium profile of the sea bed is attained based on the measurements.

Abstract: This paper outlines a simplified experimental technique for the measurement of scour around pile foundation in laboratories. There are certain difficulties in predicting the scour depth as the particulate movement of sediments due to scour is time dependent. Considering the complexity of the problem, a suitable instrumentation system has been developed and adopted for measuring scour depth with time till the equilibrium profile of the sea bed is attained based on the measurements, a relationship for the scour depth in terms of properties of sediment model characteristics and fluid parameters has been suggested. A detailed laboratory testing programme on model piles of diameters 50 mm to 110 mm was carried out in a wave cum current flume of 30 m length, 2.0 m width. Currents (velocities are between 0.19 and 0.32 m/sec) are generated by the circulation of water through inlet and outlet arrangements for the operating water depths ranging between 30 cm and 60 cm over the test section. The time development of scour process around a single vertical pile is studied due to steady current, combined action of waves and current. To highlight the usefulness of the instrumentation and understanding the principle of measuring scour around the pile, studies are discussed in the case of only currents.

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References
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Journal Article•DOI•
Cohesive Material Erosion by Unidirectional Current

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J. William Kamphuis, Kevin R. Hall
01 Jan 1983-Journal of Hydraulic Engineering
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.

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Journal Article•DOI•
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Kuninori Otsubo, Kohji Muraoka
01 Oct 1988-Journal of Hydraulic Engineering
TL;DR: In this article, the authors defined two threshold levels for mud transport and divided muds into two groups by their characteristics (settling type, flow curve, resuspension behavior, etc.).
Abstract: The main purpose of this study is to obtain a simple critical shear stress function for cohesive soft bottom sediments. A series of experiments concerning threshold levels of mud transport and two series of tests of their rheological and setting properties were conducted to find some correlation among these indices. We defined two threshold levels for mud transport and divided muds into two groups by their characteristics (settling type, flow curve, resuspension behavior, etc.). In discussing the factors determining the characteristics of the two groups, we found that natural muds usually belong to the first group, in which the two critical shear stresses are given as a function of yield value τy1 (defined in paper) independent of material, following a new definition of threshold for sediment detachment from the bed. Finally, the correlation between this yield value and the final settling volume ratio is also discussed.

91 citations

Time Scale Of Scour Around A Vertical Pile

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B. M. Sumer1, N. Christiansen1, Jørgen Fredsøe1•
Technical University of Denmark1
01 Jan 1992
TL;DR: In this article, the scour process around a single vertical pile was studied both in steady current and in waves, and an extensive series of tests were carried out in a current flume and in a wave flume with various sizes of circular cross-section piles ranging from 30 mm to 510 mm.
Abstract: The time scale of the scour process around a single, vertical pile is studied both in steady current and in waves. An extensive series of tests were carried out in a current flume and in a wave flume with various sizes of circular cross-section piles ranging from 30 mm to 510 mm in the steady current case and from 10 mm to 40 mm in the wave case, using sand.

82 citations

Journal Article•DOI•
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Y J Peirce, R.T. Jarman, C M De Turville, C M D Turville, Cegb 
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14 citations

Proceedings Article•DOI•
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A.W. Niedoroda1, C. Dalton2, R.G. Bea1•
Woodward, Inc.1, University of Houston2
01 Jan 1981

11 citations

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