The viscous component in slow moving landslides: A practical case

The availability of continuous records of both velocities and groundwater table in monitored landslides has increased the interest of the scientific community for the dynamics of the slow moving landslides. In this paper we analyse the role of the viscous component in large landslides by using ten years record of monitoring data from the Vallcebre translational landslide, located north of Barcelona (Spain). Previous research showed that a viscosity term should be considered in order to reproduce the measured displacements in this landslide. We discuss here the hysteretical behaviour of the landslide velocity records observed during some acceleration events produced by the rise and withdraw of the groundwater table. The conceptual model we have used shows that a constant viscous component of the movement is not able to explain the hysteretic behaviour and that consequently, other mechanisms should be searched to explain such a behaviour.