A Novel Framework for Predicting Landslide Mechanism in Norwegian Quick Clays

Accurate prediction of landslide susceptibility and retrogression potential is crucial for risk assessment of marine clay slopes. While Canadian and Norwegian practices generally align on the key factors controlling retrogressive landslides, they differ in the selection of threshold values. This study compares methodologies for assessing retrogression in sensitive clays. One Canadian approach compares the potential energy of a slope with the energy required to remold the clay during a landslide. It aims at identifying a threshold of potential energy above which the clay is sufficiently remolded to develop into a large retrogressive landslide. In this study, the Canadian approach is tested against a revised and updated database of Norwegian quick clay landslides. Due to relatively lower undrained shear strength and plasticity indexes, a higher threshold is suggested in Norway. Building on these findings, a new framework is proposed to predict the most likely landslide mechanism. When tested against the Norwegian database, the framework accurately predicted whether a sensitive clay slope was most susceptible to rotational, flake, or retrogressive landslides.