A practical approach for predicting landslide retrogression and run-out distances in sensitive clays

In the present study a novel approach of practical interest is proposed to perform a predictive analysis of the landslides in sensitive clays. Specifically, this approach allows a prediction of the landslide triggering along with the consequent distances of retrogression and run-out. To this end, a simple limit equilibrium solution is proposed to deal with the first two steps (prediction of the landslide triggering and the subsequent retrogression distance). A calculation code based on the material point method (MPM) is instead employed for evaluating the run-out distance of the unstable soil mass that was defined in the previous step. Operative values of the undrained shear strength are also suggested for each of the aforementioned steps. The proposed method is very attractive from a practical viewpoint because it is simple to use, not time-consuming and requires few geotechnical parameters of easy experimental determination as input data. The method is applied successfully to several well-documented case studies available in the literature, demonstrating also its reliability for engineering applications. Three of these landslides are analysed in more detail to illustrate the application of the present method to real cases.