Wireless monitoring for cliff stabilization at La Clua (Pre-Pyrenees, Spain)

Abstract

La Clua is a village at the foot of a conglomerate cliff (Pre-Pyrenees, Spain), eventually af-fected by rockfalls. After last big event, in 2009, that affected a house of the village, a rope net was installed to protect the village. In order to obtain information about the performance of the protecting net, but also to gain knowledge on the triggering mechanism a wireless mon-itoring system was installed. The system is equipped with sensors (4 crackmeters, 2 biaxial tiltmeters, 2 rope tension load cells and 2 thermistors) that are measuring the changes on two unstable boulders (one protected with the net, the other not). Sensors are connected to wire-less dataloggers, installed next to the sensors and send data to the gateway. In this site, gate-way is located 250 m far from the furthest logger, but thanks to the long range technology of the system, loggers can be up to several km far from the gateway and the data which is pushed to an internet server every 15 minutes. Preliminary results show that no relevant movements have been observed in the boulders, since February 2016. Only some slight changes of around 0.15º have been observed after heavy rainfall events in spring.