A geomechanical evaluation of the rock mass involved in the 1963 Vajont Landslide (NE Italy)

Abstract

The Vajont landslide (NE Italy) occurred on the 9th October 1963, when approximately 270 million m3 of rock slid down into the existing reservoir at 20-30 m/s. The movement involved limestones and marls of the Fonzaso and Socchér Formations and occurred along a chair-like sliding plane. The landslide has been object of numerous studies but a comprehensive explanation of its triggering and dynamics remains elusive. Here we report the results of new structural and geomechanical data from conventional mapping on 88 field stations within and outside the landslide. Each station includes joints orientation, spacing, persistence and roughness, Geological Strength Index and Schmidt Hammer tests. The characterization of the landslide deposit was completed by the description of seven boreholes drilled by RODIO Company in 1965 down to the sliding surface. Representative rock samples were collected for laboratory measurements of the unconfined compressive strength, Young modulus and Poisson's ratio. The new data represent an important tool to reconstruct a detailed 3D geological and geomechanical model of the landslide. © Springer-Verlag Berlin Heidelberg 2013.