Geotechnical modelling of iceberg-seabed interaction

• Main Author: Green, Herbert Paul
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 1984
• Subjects: Newfoundland
• Online Access: https://research.library.mun.ca/5254/; https://research.library.mun.ca/5254/1/Green_HerbertPaul.pdf; https://research.library.mun.ca/5254/2/Green_HerbertPaul.pdf

Exploratory drilling on the eastern Canadian continental shelf has proven the presence of commercially viable quantities of hydrocarbons. Any process to extract the resources from beneath the seafloor offshore Newfoundland and Labrador has to take into account the severe environmental condition some of which are unique to this geographic region. Damage to seafloor installations such as pipelines of wellheads by bottom dragging or scouring icebergs is one of the potential problems. This has been recognized since the early 1970’s. However, methods of estimating the maximum iceberg scour depths and methods of protecting seabed installations are still topics of research. -- In this thesis an experimental approach was taken to physically model the iceberg scour process in a 14 m x 3 m x 1 m towing tank. Cohesionless soil at a uniform slope and with controlled properties was used as the representative seafloor material. Iceberg models 500 mm wide and a pipeline model 122 mm diameter were instrumented and used in a text programme aimed primarily at examining the interaction of the iceberg model and the soil and delineating the influence of the scour process below the incision depth. -- For a horizontally scouring iceberg the frontal soil resistance was found to be the major affecting the scour size. The shape of the iceberg keel in contact with the soil was also found to be an important parameter in the scour process. The tests indicate that the zone of soil disturbance extends below the keel of the scouring iceberg. This zone of influence should be accounted for in the design of all buried installations in the Newfoundland and Labrador offshore region.