Advance survey and modelling technologies for the study of the slope stability in an Alpine basin

Alpine basins are typically characterised by an amphitheatre shape with steep rocky walls on the upper, a deposition zone of glacial debris in the middle and a channel in the lower part. All different parts are in constant evolution, and different kinds of instability phenomena can be identified: rock fall at the top rocky walls, rotational sliding of the deposit and debris flow in the channel down the valley. The different kinds of instability are somehow connected among them since the rock fall can power the rock debris that can trigger a debris flow. All different phenomena are chained in a global basin evolution also connected with seasonal climate variation that can induce different water presence and different water phase (liquid/solid). Moreover, instability phenomena seam to increase in frequencies and magnitudes in the latest decades possibly connected to climate change. This paper reports a study of the stability condition of an Alpine basin in North-West Italy by applying advance survey and modelling techniques: aerial photogrammetric survey of the rock wall, limit equilibrium methods that take ice presence into account and finally numerical analysis of the debris evolution along the slope. Parametric analyses aimed to quantify the influence of the different most important aspects have also been carried on. The application of advanced tools helped to better understand the study area failure and evolution mechanisms and to identify the main points to investigate in detail.