Quantitative bearing capacity assessment of strip footings adjacent to two-layered slopes considering spatial soil variability

The probabilistic bearing capacity of the strip footing placed near a two-layered cohesive soil slope is evaluated using random adaptive finite element limit analysis with anisotropic random field modeling and Monte Carlo simulation techniques. To account for the combined effect of geometric parameters (i.e., normalized slope heights, and slope angles), soil properties (i.e., ratio of undrained shear strength from two-layer soils) and spatially variable strengths of two-layered soil, the bearing capacity is quantitatively examined in stochastic analysis. Moreover, a sensitivity analysis is exhibited, and the optimal layout of footings near a two-layered slope is estimated through a multivariate adaptive regression splines procedure. The associated results demonstrate that the slope angle has the most significant impact on the mean bearing capacity, while the coefficient of variation of the ultimate bearing capacity factor could be greatly reduced by decreasing the variability of the upper layer soil. The interaction effects between these influencing factors are numerically investigated. This study highlights the prominent role of the variability in lower layer soil when the coupled influence of geometric conditions and soil properties is considered.