Modelling Rockslide Displacements with Delayed Plasticity

Abstract

To model the temporal evolution of complex landslides, a 1D pseudo-dynamic viscoplastic approach, based on Perzyna's theory, has been modified. In the original version of the model, the viscous nucleus has been assumed to be bi-linear: where irreversible deformations develop uniquely for positive yield function values whereas, in a more general case, it can also develop for negative values. In this work the model has been enriched by considering: (1) an exponential viscous nucleus, (2) a strain-rate softening to reduce friction angle as the sliding velocity increases and (3) block interaction forces to cope with complex 3D geometries for the sliding mass .The application of the proposed model to the Vajont slide emphasizes the role played by the strain-rate softening while the application to the La Saxe rockslide (Italy) clearly shows how a relatively simple model can be applied to a complex landslide by considering a spatial discretization of the sliding mass.