MONITORING OF THE MOVEMENTS OF A DEEP, SLOW, CLAYEY LANDSLIDE AND 3D INTERPRETATION

This paper is focused on the movements of Costa della Gaveta landslide, that is an active, deep and very slow Italian landslide being monitored and studied since 2004. In 2012 new boreholes have been carried out and inclinometer tubes installed to deepen the comprehension of the 3D geometry and kinematics. Localized displacement on a slip surface is the prevailing mechanism of movement. Howewer, thanks to the long term monitoring, even the slow internal viscous deformations of the landslide body have been evaluated and interpreted. Soil discharge is constant in the track. This characterizing kinematic feature allows a first approximation prediction of the landslide behaviour on empirical basis. To further improve such prediction and, thus, the risk management of the area, a 3D FEM theoretical model has been constructed. A large difference in the safety factor between 2D and 3D analyses is observed.