Modelling Multiphase Geomaterials at High Temperatures in Dynamics with Application to Strain Localization and Rapid Catastrophic Landslides

摘要

This paper presents a finite element analysis of non-isothermal elasto-plastic multiphase geomaterials in dynamics including frictional heating generation. A fully coupled mathematical model is developed within the Hybrid Mixture theory. A computationally efficient reduced formulation is derived following the u-p-T approach. Two strain localization problems are simulated. The first one is a plain strain compression test of globally undrained water saturated dense sand. The second test concerns a rapid strain localization example inspired by the Vajont landslide (Italy, 1963). The numerical results show that cavitation occurs at strain localization in the first test and the frictional heating increases slightly the temperature in the shear band, anticipating the onset of cavitation in comparison with the case neglecting the heating generated by friction. The second numerical test shows a temperature increase in the shear band much higher than the boiling temperature of the liquid water, with consequent formation of a vapor cushion and loss of shear strength. These simulations show that frictional heating generation may have a role in dynamic strain localization, in particular during the development of rapid catastrophic landslides.