The shear resistance available at the base of a landslide body exerts a fundamental control on the evolution of its movement. This resistance can vary in time and along the basal surface (or shear zone) of the landslide body according to the nature of the sheared material, its stress-strain state and porosity, the amount of moisture and the pressure of fluids in the pores. In addition, changes of temperature, chemistry, and shear velocity (or strain rate) can give rise to feedback mechanisms that can be responsible for long and slow shear creep phases or for runaway, long-runout sliding. A transition between these two modes is also possible under certain mechanisms controlled by external constraints. In this thesis, the candidate will provide a state of the art review on velocity-dependent and other feedback mechanisms on landslide movement, with a particular focus on velocity weakening mechanisms associated with catastrophic sliding. An overview of recent experimental results and modelling approaches for long runout landslides will also be presented and discussed, so as to provide a comprehensive basis that could be subsequently defeloped into an understanding of the role of long runout landslides in landscape evolution, as well as of the risk associated with their occurrence in anthropized regions.
Preliminary scope of work in English
The shear resistance available at the base of a landslide body exerts a fundamental control on the evolution of its movement. This resistance can vary in time and along the basal surface (or shear zone) of the landslide body according to the nature of the sheared material, its stress-strain state and porosity, the amount of moisture and the pressure of fluids in the pores. In addition, changes of temperature, chemistry, and shear velocity (or strain rate) can give rise to feedback mechanisms that can be responsible for long and slow shear creep phases or for runaway, long-runout sliding. A transition between these two modes is also possible under certain mechanisms controlled by external constraints. In this thesis, the candidate will provide a state of the art review on velocity-dependent and other feedback mechanisms on landslide movement, with a particular focus on velocity weakening mechanisms associated with catastrophic sliding. An overview of recent experimental results and modelling approaches for long runout landslides will also be presented and discussed, so as to provide a comprehensive basis that could be subsequently defeloped into an understanding of the role of long runout landslides in landscape evolution, as well as of the risk associated with their occurrence in anthropized regions.
