Thompson Engineering performed a geotechnical investigation at a proposed platform located 26-miles offshore in the High Island Area of the Gulf of Mexico. The purpose of the investigation was to obtain data to develop foundation design recommendations for a fixed offshore structure. A single soil test boring was performed to a depth of 277 ft. below the seafloor in a measured water depth of 500ft.
Thompson drill crews and equipment were transported from a dock to the 145 Class L/B Grand work vessel on a supply vessel. The soil test boring was completed using a CME 550X geotechnical drill rig positioned over the work vessel’s moon pool.
Soil data was collected using a 3-inch outside diameter, thin-walled tube sampler where fine-grained soils were anticipated. A 2-inch split-spoon sampler was used where coarse-grained soils were anticipated. All samples were obtained by pushing the samplers into the soils either under the weight of the drill string or hydraulic assistance.
The in-situ soils were sampled at 3-foot intervals up to depths of 50 ft. below the seafloor, at 5-foot intervals for 50 to 100 ft., and at 10-foot intervals below 100 ft.
The recovered soil specimens were visually classified by experienced Thompson geotechnical engineering staff in accordance with ASTM D-2487. Laboratory tests were performed to determine soil strength and an analysis was performed on 36-in. and 72-in. diameter driven pipe piles. A geotechnical report was submitted to our client including all soils and pile analysis data.