It is well known that the accuracy of a slope stability analysis is strongly dependent on the soil shear strength estimated along the potential sliding surface. Typically, the soil strength is expressed by the Mohr-Coulomb failure criterion which gives the shear strength as a linear function of the effective normal stress on the shear surface. However, there is now considerable experimental evidence to show that several types of soil and compacted rockfill exhibit a non-linear failure envelope with significant curvature at low effective normal stress levels. The non-linearity of the soil failure envelope is particularly important for problems related to slope stability since they commonly involve a large range of effective normal stresses. This project focuses on laboratory investigations of the nonlinear character of the strength envelope for compacted fill materials based on triaxial tests, and the lab results are employed in comparative slope stability analyses using the traditional Mohr-Coulomb and non-linear failure envelopes derived from the experimental data. The study aims to emphasize that an evaluation of landslide risk using the traditional Mohr-Coulomb linear strength envelope is not on the safety side for slope materials exhibiting a non–linear failure envelope. Therefore, a slope stability analysis accounting for the nonlinear character of the strength envelope is more appropriate in order to correctly assess the failure risk of slopes for such circumstances.





Back