Application of probabilistic methods in geomechanics

Three probabilistic methods of different complexity for slope stability calculations are in this work evaluated with respect to a well-documented case study of slope failure in Lodalen, Norway. A finite element method considering spatial random fields of uncorrelated parameters cohesion and friction angle is taken as a reference for comparison with two simpler methods based on Taylor series expansion, known as first-order-second-moment methods. It is shown that the FOSM method enhanced by a reduction of variance of input parameters due to spatial averaging along the potential failure surface leads to a significant improvement in predictions. This method is computationally inexpensive and can be used in combination with any existing finite element code, it is thus a useful approximate probabilistic method for geotechnical practice. Several limitations of the extended method for calculating probability of a slope failure are identified. An advanced hypoplastic constitutive model is used in probabilistic analyses of a typical geotech- nical problem, strip footing. The model, including horizontal and vertical correlation lengths, was calibrated using a set of experimental data on sand from horizontally stratified deposit. Some parameters followed normal, whereas other followed lognormal distributions...