Geotechnical Investigation of Subsoils for Foundation Design in Port Harcourt, Nigeria
DOI: 10.23977/geors.2020.030103 | Downloads: 2 | Views: 108
Ebiegberi Oborie 1, Edirin Akpofure 1
1 Department of Geology, Niger Delta University, Wilberforce Island, Bayelsa State, Nigeria
Corresponding AuthorEbiegberi Oborie
Geotechnical investigation was carried out at a proposed construction site in Port Harcourt, to establish the soil profile and determine the engineering geological properties of subsoils in the area. Boring activities were conducted in 4 locations at the site by means of a manual percussion rig to a depth of 30m. Visual observation and laboratory analysis of the recovered samples reveal that the subsurface materials in the area consist of soft clays from the existing ground surface to an average depth of 5.0m. Beneath the clay formation are different sand facies which occur to the final depth of the boreholes. Shallow foundation analysis conducted on the soil samples gave allowable bearing capacity values ranging from 35 -78kN/m2 for square footings founded at depths of 0.5 - 2.0m. Total settlement from the anticipated imposed load of the proposed structure was determined to range between 70 and 52mm at foundation depths of 0.5 and 2.0m for square footing of 1.0m, while settlement for 5.0m footing, was evaluated to be 130 and 80mm at foundation depths of 0.5 and 2.0m respectively. Pile foundation analysis was also carried out for the soil profile encountered at the site. Straight shaft, closed pipe piles of diameters 305, 406, 508 and 610mm were designed. The pile compressive resistance of the 305mm diameter pile was between 20 and 740kN when founded between 5.0 and 30.0m depths respectively, while that of the 610mm diameter pile gave a compressive resistance between 50kN and 1690kN when founded between the same depths. It is therefore recommended that while shallow foundation could be used for supporting structures within the study area, pile foundation should be considered for multi-storey buildings.
KEYWORDSBorehole, Foundation, Footing, Bearing capacity, Settlement, Compressive resistance
CITE THIS PAPER
Ebiegberi Oborie,Edirin Akpofure, Geotechnical Investigation of Subsoils for Foundation Design in Port Harcourt, Nigeria. Geoscience and Remote Sensing (2020) Vol. 3: 17-28. DOI: http://dx.doi.org/10.23977/geors.2020.030103.
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