Reliability evaluation of shallow foundation bearing capacity on c′, φ′ soils

As our understanding of soils has been steadily improving, the characteristics of its variability can now be highlighted. This has practically changed our geotechnical modus operandi from strictly deterministic models to semiprobabilistic or even strictly probabilistic models. The latter are still to be regarded as experimental and cannot, for the time being, be used routinely in practical working applications. However, the ongoing, continued research and study of these methods combine to develop their worth and bring out any drawbacks. This paper proposes a possible application of probabilistic methods to the study of shallow foundations reliability with respect to their bearing capacity. The study concerns a foundation on a soil characterized by effective cohesion c' and friction angle f', considering possible values of correlation coefficients between them and taking into account the effects of vertical fluctuation scale. The results show that higher reliability indexes are found when correlations between c' and f' are negative and when the fluctuation scale has a minimum value.