ABSTRACT
The first offshore oil rig 'Superior' was installed in 1947, 18 miles from the coast of Louisiana in the United States, in just 6 m depth of water. Greater distances separating the offshore development from land have necessitated either local storage, mainly for liquids, and periodic offloading onto tankers, or long export pipelines. There a number of distinguishing features of geotechnical engineering for offshore conditions. Site investigations are extremely expensive, with mobilisation and hire costs of suitable vessels typically several million US dollars. Soil conditions are often unusual, particularly in respect of carbonate soils and corals. This chapter deals with the aspects of offshore geotechnical engineering. Geotechnical aspects of design are mostly concerned with the stability of the pipeline on the seabed, either buried within a trench or laid directly on the seabed, and what are the limiting interaction forces between the pipeline and seabed that govern stability.
