Geotechnical Site Investigation for a Proposed Marginal Field Development in a Swamp Location

Abstract This study was carried out to investigate and determine the geotechnical parameters required for adequate design and positioning of structures and facilities in a swamp location. 106 samplings were carried out in the boreholes (both on land and over water) to obtain samples for laboratory analysis. In all the boreholes, 92 disturbed samples were collected using the split spoon sampler (SPT samples) and from the drilling spoils. These were properly labelled and placed in watertight bags to ensure sample integrity while undisturbed samples were collected using an open-tube sampler. Both ends of the tube were properly sealed, labelled and secured. Selected soil samples were analyzed and carried out in accordance with BS1377 for engineering properties. The moisture content for the clay layers ranges between 31% and 163% which indicates that the clay has a low to high moisture content typical of marine clays, The bulk unit weight of the clay ranges between 12.52kN/m3 and 19.44kN/m3. The results of the liquid limit show that the value ranges between 88% and 140% while the plastic limit ranges between 27% and 42% and the plasticity index ranges between 61% and 98%. The SPT N-values for the sand, ranging between 6 and 14 confirmed that the sand is loose to medium dense in compaction. The results of the investigation enabled the planning and design of structures required for asset development.