Local scour and scouring protection of drilling platforms in the arctic sea environment

Placing an obstruction, such as for instance an artificial island platform, on the sea bottom will cause a disturbation in the bottom equilibrium. As a result a local scour-deposit phenomenon may occur, which especially in sandbottoms can significantly reduce the stability of platform and cause nonuniform stress distributions under the platform base. An increase of stresses over the design value may, in extreme cases, cause the failure of a whole structure. Being aware of the scouring phenomenon and undertaking the scouring protection measures already before the platform installation is in general more feasible than to try to repair damages afterwards. In the paper the local scouring due to waves and currents near the toe of gravity platforms is described. The description concentrates mainly on the artificial gravity platforms in the shallow waters (water depth ~ 10 -30 m). Scouring phenomenon and scouring protection measures are described on the basis of the available literature on the subject. Moreover some speculations concerning the model testing procedures are presented, too.