Twenty-five years of Vallcebre landslide monitoring: from theodolite to Radar

摘要

In this contribution we present the work carried out for monitoring the displacements of Vallcebre landslide (Eastern Pyrenees, Spain) between 1987 and 2012. The landslide, which extends over an area of 0,8 km~2 and involves more than 20 million cubic meters, has experienced displacements as large as 1 m per year in some points. It has been periodically monitored since 1987, using a wide range of surface and in-hole techniques, successively: triangulation with theodolite, Terrestrial Photogrammetry, Electronic Distance Measurement, GPS, inclinometers, wire extensometers, piezometers, DInSAR and GBSAR. The results using the new techniques have been compared with those obtained with the GPS and the wire extensometer, and checked against fixed stable points. From this comparison, we conclude that even though wire extensometers and inclinometers may have the highest precision, in practice all the systems have their own role in providing meaningful data for the monitoring at different study stages. After the evaluation of the precision and advantages of the different methods, the complementary use of some of them is strongly recommended.