Exploring rate and temperature effects on residual strength. Review andimplications for a landslide case study

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Abstract

A large landslide immediate to a reservoir, identified in 2006, is the guiding case to discuss its triggering, namely a consequence of fast reservoir drawdown, and its post-failure response. The reactivation of the landslide, twelve years later, allowed the validation of some hypotheses assumed in the first study (2012). The risk of landslide acceleration, for a constant residual friction and an assumed thermal pressurization of the sliding surface, was not realistic since the landslide never accelerated. In recent years, efforts have been addressed to gain further knowledge by developing advanced numerical tools and a better understanding of clay shear strength. The paper presents the developments achieved. The results of a comprehensive experimental program to investigate the effect of shear strain rate and temperature are presented for a variety of soil types. The expected landslide response under rapid drawdown conditions was simulated by a material point method-based numerical tool that handles, in a dynamic formulation, large displacements and soil /rock materials characterized by temperature, strain rate, and strain softening dependence. The risk of landslide acceleration, predicted in the 2012 analysis looks, at present, as a remote event.

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Short Curriculum

Núria Pinyol is Associate Professor in the Geotechnical Division of the Civil and Environmental Engineering at Universitat Politècnica de Catalunya (UPC-BarcelonaTech). Her research emphasizes thermo-hydro-mechanical couplings in porous media from a theoretical, numerical, and experimental point of view. Her contribution to the analysis of landslides focuses on analytical, FEM, and MPM -based analysis of slope instability and post-failure response in saturated/unsaturated soils including thermal pressurization and soil liquefaction.