A STOCHASTIC APPROACH FOR SETTLEMENT PREDICTIONS OF SHALLOW FOUNDATIONS

This Paper concentrates on computational methods for the analysis of settlement and differential settlement of shallow foundations due to the spatial variability of soil. The soil is modelled as a random elastic medium with constant Poisson's ratio and a random shear modulus characterized by average value, standard deviation and autocorrelation function. The stochastic integral formulation is used to calculate the covariance matrix of the displacement associated with a circular load acting on a semi-infinite elastic medium. The method requires less computational effort than the classic stochastic finite element method. A general method for calculating the statistical properties of the differential settlement between several shallow foundations is also presented. This is applied to the analysis of the differential settlement between two footings and the problem of two beams acting on three supports. Results show that spatial correlation of the shear modulus reduces the correlation of the vertical displacement at the surface of the soil. The coefficient of variation of the differential settlement associated with two beams acting on three supports is found to be proportional to the rigidity of the beam.