The Effect of Natural Thermal Cycles on Rock Outcrops: Knowledge and Prospect
Résumé
In recent years, interest in the effect of positive temperatures on rock faces has increased, as evidenced by the extensive literature on the subject. The subsurface rock masses of rock slopes are submitted to uncontrollable natural temperature cycles which cause deformation, displacement, opening and closing of discontinuities and can lead to surface failure or more important rockfalls. In this paper we offer a review of the publications on this theme focusing on in situ observations and measurements. Measurements are described and analysed considering conditions of temperature and insolation, displacements, strains, focusing on two French sites (Les Rochers de Valabres and La Roque-Gageac). Mechanical analysis is then performed. The impact of temperature variation is studied from basic assumptions to much more complex ones. Thermoelasticity is first assessed, and analytical computation is suggested, fracture mechanism and fatigue are also considered. Finally, we outline some challenges to be addressed in the coming years.