Abstract Due to the need to found a large horizontal Liquefied Petroleum Gas (LPG) Tank, a detailed geotechnical investigation was carried out to determine the geological nature of the subsoils at the site. The location is within the marginal lands of the Nigerian Niger Delta subregion. This was with a view to determining soil properties and conditions of subsoils regarding (i) the bearing capacity of the subsoil (ii) the foundation types and rates of settlements that are appropriate for the proposed project site. The field investigations included a detailed surface geological mapping, hydrological assessment and subsurface geotechnical investigation involving detailed SPT drill tests at X3 Nos points down to the depth of 30.00m. The geotechnical investigations reveal the following subsurface lithology: (1) Engineered Fill (SP), (2) Reddish-Brown Stiff Silty Clay layer (CL), (3) Reddish-Brown Clayey Sand Clay layer (SC), (4) Reddish Brown Silty-Clay Layer (CL), (5)Reddish-Grey Sands-Silts Layer (SM) and (6)Milky- Light Grey, Poorly Graded Sand layer (SP). The geotechnical characteristics of the subsurface materials include (a) Soil friction angles of (ϕ) = 8-34o , cohesion (c) of 0.00 - 45 kPa, Bearing capacity values of between 141.64 and 221.89 kPa. Settlement values ranged from 0.60 to 1.163 which is within limits. This paper presents the details of the study and the results.

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