Bearing Pressure of Foundation on Strong Layer Overlying Weak Clay Accounting for Compressibility

The present study analyzes response of a circular footing on two-layered clays. Several solutions are available for the ultimate bearing capacity of foundations on two-layered soil but none considers the compressibility of the layers. Strong and stiff layer of thickness, H, overlies a soft and weak clay with E1 > E2 and cu1 = 2.5cu2, where 1 and 2 correspond to top and bottom layers, respectively. Finite element axisymmetric analysis is carried out to evaluate the bearing pressure, q, versus settlement responses for ranges of stiffness ratio (RE  = E1/E2) and different thicknesses of top layer. Variations of bearing pressure factors (Ncf = q/cu1) for circular footings of diameter, D, are obtained at different settlement ratios (SR), for a wide range of RE. Results are validated with the Merifield and Nguyen (Geomech Geoengin 1:151–162, 2006) for considered cases of layered clays with different H/D. Variation of Ncf with stiffness ratio, RE, for different SR and H/D ratios are presented and analyzed.