Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.731624
Title: Ice gouging in sand and the associated rate effects
Author: Arnau Almirall, Sergi
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2017
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Abstract:
Seabed gouging by ice, also known as ice scouring, is a common feature of the Arctic and sub Arctic regions of the planet as well as in Antarctica. It is a phenomenon which occurs when ice moves while in contact with the seabed. Ice gouging is of economical significance due to the probability of disruption of seabed structures such as subsea pipelines. Small scale laboratory tests were conducted at 1g to investigate the scour force produced when a scaled iceberg model scours a test bed in dry and saturated conditions. The tests were conducted for a range of scour depths, scour widths, frontal rake angles and soil conditions to study the performance of a rigid indenter (iceberg keel) scouring a test bed. Furthermore, the tests were also conducted at various speeds to study the rate effect in sand. The effect of the drifting speed on the drag force was found to be important: a sandy seabed scoured by an iceberg with a mean drifting speed of 0.1 m/s can generate scour loads twice as large as the static loads. The methods used currently to predict ice scour loads consider only the static loads under drained conditions and these should be revised. The PIV (Particle Image Velocimetry) technique was utilized to study the sub-gouge deformation and the soil failure mechanism associated with ice gouging. The soil resistance and the sub gouge deformation results obtained in the laboratory were compared with centrifuge investigations (the PRISE and PIRAM programs) in order to examine the viability of extrapolating the results from the model scale to a prototype scale.
Supervisor: Not available Sponsor: University of Aberdeen
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.731624  DOI: Not available
Keywords: Ice ; Ocean bottom ; Icebergs ; Drift ; Scour (Hydraulic engineering) ; Underwater pipelines
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