Instrumentation problems related to determining geotechnical properties of ocean sediments

The extraction of most oceanic resources including the methods and economics is influenced by the nature and type of the ocean floor as well as the extent to which the geotechnical properties of the ocean bed can be confidently evaluated. In the near-shore and inner continental shelf zones, methods for such evaluation are mostly extensions and modifications of the conventional procedures used onshore. With the expansion of offshore activities into deeper zones, new techniques are needed for preliminary and detailed evaluation of ocean bed characteristics if operations in these deeper regions are to be viable. In recent years, there has been a proliferation in the instrumentation for offshore environments. Geotechnical engineers generally have limited exposure to sophisticated instrumentation techniques, nor are the instrumentation engineers fully conversant with details of geotechnical measurements and their application. This paper reviews the methods currently used for evaluating geotechnical properties of the ocean floor including sampling (corers, etc.), in situ testing (shear vanes, penetrometers, etc.), and indirect (seismic, acoustic, etc.) techniques. The type of data that a geotechnical engineer generally wishes to obtain, the problems in obtaining them, and the application of the data in practice are briefly reviewed.