Stochastic analysis of foundation immediate settlement on heterogeneous spatially random soil considering mechanical anisotropy

The study presents a probabilistic immediate settlement analysis of shallow foundations resting on an anisotropic soil layer of spatially random properties. To this end, a rigid foundation of quite negligible slippage has been considered. Stochastic finite element method along with the numerous Monte Carlo simulations is implemented to explore the potential influence of mechanical anisotropy on the elastic settlement of a single spread footing. The analysis is also performed for the differential undrained settlement response of a pair of shallow foundations. Exploiting variable stochastic properties for the soil elastic modulus, including covariance, scale of fluctuation and cross-anisotropy ratios, several realizations of the respective soil stiffness measure are adopted, leading to the consequential corresponding realizations of the shallow foundation settlement. The results of the numerical simulations show that the increase in the elastic modulus anisotropy ratios leads to a dramatic reduction in the induced foundation settlement. Furthermore, it was observed that with the increase in the auto-correlation distance for the soil elastic modulus, the discrepancies between the evaluated settlements using deterministic and stochastic analyses grow more phenomenal. The computed settlements of the footings, considering the substantial effect of soil anisotropy, are also observed to be greater when a stochastic analysis is employed.