The paper reports some results of geotechnicalinvestigations carried out to investigate the evolution ofground displacements in a large landslide measuring 1.6km from top to toe (0.6 km at top, 1.2 km at toe) involvinga varicoloured clay formation in the district of Palermo inSicily. In order to analyse the landslide mechanisms anddevise stabilization works, an extensive programme of insitu and laboratory geotechnical investigations was carriedout, and a monitoring system was installed, comprisingrain gauge, piezometers, inclinometers and numerous landmarks to measure movements at ground surface.Monitoring was performed from instrument installation(autumn 2008/late spring 2009) until December 2011. Thereactivation of the overall landslide was triggered by anearthquake in 2002 September, while successivemonitored episodes are related to rising piezometric levelsinduced by rainfall.Several distinct active zones can be contoured wheredisplacements are evolving at variable rates in differentdirections on the landslide surface. The evolution in timeof the displacements is clearly affected by rain. Withreference to two of the most active zones, labelled zones Aand B, it is shown that displacement rates increase ordecrease as piezometric levels rise or fall depending onrainfall. In zone A two active slip surfaces can be detected,located at different depths from ground surface, whereasback analyses carried out show that operative shearstrength is consistent with the laboratory measuredresidual shear strength of the involved tectonised clays.
|Number of pages||8|
|Publication status||Published - 2014|