Probabilistic Assessment of the Bearing Capacity of Shallow Strip Footings on Stiff-Over-Soft Clay

This paper focuses on the probabilistic assessment of the resistance factor for bearing capacity for a strip footing on a stiff-over-soft clay profile. The analysis is performed by applying the Random Finite Element Method, which combines finite element simulation, spatial variability analysis and Monte Carlo simulation. Finite-element analyses are performed in the program ABAQUS on meshes in which undrained strength values are assigned on the basis of quantitative estimates of the vertical and horizontal spatial variability and the probabilistically modelled scatter of undrained strength itself. The stochastic implementation of the numerical analyses results in samples of bearing capacity factors which, when normalized by a deterministic bearing capacity factor, provide a set of tabulated factors calibrated to user-defined target reliability levels. The results have application for the prediction of foundation punch-through, where the footing pushes the upper strong layer of soil into the softer clay beneath.