SB Akpila and IW Omunguye
Keywords: Deviator stress, undrained cohesion, deformation, foundation settlement
Abstract: A study based on the stress-strain behaviour of soils in four areas within Port Harcourt has been carried out. In this study, deformation trends on stress and strain, derivative of stress and strain, and ratio of deviator stress to undrained cohesion to strain were established. Higher stability and lower deformation of soils response to loading were in descending order of Rukpoku, Ada George, Borikiri and Abuloma areas. At low strains, soil modulus E, generally reduced with increase in strain converging towards 3.5% strain and subsequently, exhibited slight increase in value on Rukpoku and Ada George Road soils. Predicted soil moduli for the areas are generally within the range of E, identified as soft to medium clay soils, except for Rukpoku soils that are within the range of hard clay. Predicted values of the ratio of deviator stress to undrained cohesion and strain, at strain level of 1% are generally lower than reported field values frequently used for intact blue London clay, but are within the value used for routine work in London clay. Shallow foundation settlement input parameter of soil modulus can easily be obtained from the predictive models or values, for preliminary analysis and design.
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