Approximate displacement influence factors for elastic shallow foundations

Displacement influence factors for calculating the magnitudes of drained an d undrained settlements of shallow foundations are approximated by simple n umerical integration of elastic stress distributions within a spreadsheet. Influence factors for circular foundations resting on soils having homogene ous (constant modulus with depth) to Gibson-type (linearly increasing modul us) profiles with finite layer thicknesses are obtained by summing the unit strains from incremental vertical and radial stress changes. The effects o f foundation rigidity and embedment are addressed by approximate modifier t erms obtained from prior finite-element studies. Results are compared with closed-form analytical and rigorous numerical solutions, where available. A new solution for Gibson soil of finite thickness is presented.