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Description:
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Petroleum exploration and production in recent years have moved into increasingly deeper water off the continental shelf . Some of these facilities are anchored in water depths in excess of 1000 meters . Exploration and production in deep water present new technological challenges where traditional fixed platforms have given way to floating structures . Today suction caissons are the most commonly used anchorage system for permanent offshore oil production facility . The objective of this study is to numerically predict the ultimate capacity of suction caissons in normally consolidated and lightly overconsolidated clays . Representative soil profile from the Gulf of Mexico and the North Sea are taken and analyzed for suction caissons with length over diameter ratios of 2 , 4 , 6 & 8 . Normalized failure load interaction diagrams are generated for each of the cases . The location of optimum attachment point is also reported for each of the cases . General purpose finite element computer program ABAQUS is used for the numerical prediction . The finite element study is carried out with three -dimensional models using hybrid elements . A simplified elastic perfectly plastic model with von -Mises yield criterion is used for the study . The saturated clay is treated as an incompressible material . Results of the study compares well with existing simplified method for estimating load capacity of suction caisson anchors . |