ABSTRACT
Rockfall occurrence is governed by several factors, including rainfall episodes, seismic activity or the freezing and thawing of water filling discontinuities. Stresses and strains induced by natural thermal fluctuations have also been mentioned yet seldom quantified in situ. A monitoring network, based on the CSIRO Hi 12 strain cell installed in boreholes at shallow depths, has been deployed on a large slab of the ‘‘Rochers de Valabres’’ Pilot Site Laboratory in France. The chapter presents the results of in situ temperature and strain measurements performed at this site and focuses on the use of thermoelastic analytical solutions and laboratory testing for results interpretation. Thermally-induced strains are indeed very slow and continuous; they can however generate a cumulative effect and produce irreversible deformations. The magnitude of errors associated with both the design of devices and field conditions may very well exceed the magnitude of in situ strains.
