%0 Conference Proceedings
%T Landsliding generated by thermomechanical interactions between rock columns and wedging blocks: Study case from the Larzac Plateau (Southern France)
%+ Géosciences Montpellier
%+ Laboratoire de Mécanique et Génie Civil (LMGC)
%+ Physique et Mécanique des Milieux Divisés (PMMD)
%+ Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Direction Méditerranée (Cerema Direction Méditerranée)
%A Taboada, Alfredo
%A Ginouvez, Hadrien
%A Renouf, Mathieu
%A Azemard, Pierre
%< avec comité de lecture
%B Powders and Grains 2017 – 8th International Conference on Micromechanics on Granular Media
%C Montpellier, France
%3 Powders and Grains 2017 proceedings
%V 140
%P 14012
%8 2017-07-03
%D 2017
%R 10.1051/epjconf/201714014012
%Z Géophysique
%Z Engineering Sciences [physics]/Mechanics [physics.med-ph]/Solid mechanics [physics.class-ph]
%Z Engineering Sciences [physics]/Civil Engineering/RisquesConference papers
%X The Larzac Plateau is delimited by vertical cliffs whose geometry is controlled by vertical joints. Cliff's erosion involves landslides initiated by incremental enlargement of joints that progressively detach rock columns at very low velocities (1.2 mm/yr). We find that enlargement of joints is linked to intraseasonal thermal cycles ranging between 2-15 days in relation with dilation/contraction of rock blocks trapped inside the joints. The mechanism involves two successive stages in which blocks create a wedging and a ratcheting effect on the rock column. Wedging is associated with compressional forces acting on the rock column, resulting from temperature increase and dilation of the shallow rocks. Ratcheting is associated with downward displacement of blocks by gravity to a new equilibrium position, resulting from temperature decrease and contraction of shallow rocks. The displacement vector in a thermal cycle is split into a plastic and a thermal component; plastic displacements range between 10 – 200 μm according to the seasons, and are absorbed along a shear plane dipping ~40° beneath the rock column: they are largest during autumn and winter, minor during spring and negligible in summer. This deformation mechanism is termed thermomechanical creep as permanent deformations are associated to mechanical forces induced by short-term thermal cycles.
%G English
%2 https://hal.science/hal-01767895/document
%2 https://hal.science/hal-01767895/file/Conf_Renouf_al_landsliding_2017.pdf
%L hal-01767895
%U https://hal.science/hal-01767895
%~ INSU
%~ UNIV-AG
%~ CNRS
%~ GM
%~ LMGC
%~ GENIECIVIL
%~ CEREMA
%~ MIPS
%~ B3ESTE
%~ UNIV-MONTPELLIER
%~ UM-2015-2021