Infrastructure maintainance and countermeasures planning in complex geological and geomorphological settings

This dissertation presents the geological, hydro-geological and geo-mechanical characterization of a large landslide threating a strategic infrastructure. In the second chapter, the studied site is widely described. Site geography and strategic relevance of the valley segment is explained. The geological settings of the area are described together with the groundwater circulation. The landslide phenomenon is then reported, followed by the local climate settings. The remaining sections treat about the infrastructure. The third chapter the monitoring instrumentation installed at Passo della Morte is listed. Inclinometers and piezometers measures are compared in order to find a correlation between extreme rainfalls, rapid snowmelt events and landslide activation. A specific section treats the topographic benchmarks displacements. Fourth, the lab tests carried out on the slope materials is presented. Initially, the borehole selection is explained. Triaxial, uniaxial, point load, Brazilian and sound wave velocity tests results are presented in a subsection each. The chapter is closed by a mineralogical analysis, which support other assumption done in the modeling related to the slip surface properties. In the fifth chapter, the numerical simulations done are presented. Initially, the slip surface geometrical construction is shown. Then, a slip surface modelling strategy using no-thick elements is explained. The sensitivity analysis carried out on the model settings and mechanical parameters is later discussed in a specific subsection. Finally, a comparison between calculated and measured displacements is done. In the end, a series of countermeasure works are proposed and explained.