Engineering Applications in Permafrost Areas 497 Thaw subsidence analysis for multiple wells on a gravel island

• Main Authors: Malcolm A. Goodman, F. Joseph, Fischer, David L. Garrett
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Le Fond; Gravier; Gravel Island; Shore Island; permafrost
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.489.9269; http://pubs.aina.ucalgary.ca/cpc/CPC4-497.pdf

Sea-floor settlement, particularly differential settlement, is important for off-shore island design. For gravel islands, differential settlement at the sea-floor may result in movement of the island surface which could cause damage to surface facilities and/or require substantial amounts of make-up gravel for maintenance of island elevation. For steel gravity-type structures, differential settlement at the sea-floor could cause large stresses within the structure due to loss of foundation support. The magnitude and distribution of settlement beneath an island is dependent on thaw geometry which in turn is de-pendent on well arrangement on the island surface. This raises the following question: What well arrangement is best in order to meet the combined needs for island design, casing design, and opera-tional purposes? To provide information useful to answering this question, two different well con-figurations have been analyzed, one with wells clustered within a circle in the centre of the island and the other with wells on two concentric circles near the periphery of the island. The intent is to consider one case of concentrated thaw beneath the island centre and another case of thaw distributed more evenly relative to the total surface area of the island. L’affaissement du fond marin, surtout le tassement differentiel, est important dans la conception des iles artificielles offshore. Pour les iles de gravier, le tassement differentiel sur le fond marin peut