In many geotechnical problems either saturated or unsaturated soils are subjected to a cyclic coupled thermo-hydro-mechanical (THM) loading. A prominent example are energy piles, increasingly in demand in the context of renewable energy development. Despite its practical relevance, the complex behaviour of medium plasticity clays under coupled THM loading has not been sufficiently investigated and is thus not fully understood yet. The available constitutive models are mainly restricted to monotonic THM processes. Therefore, a thorough experimental investigation of a medium-plastic clay under coupled THM loading is planned, including oedometer and triaxial tests performed at either Charles University (CUP) or Ruhr-University Bochum (RUB). Furthermore, column-type experiments with temperature cycles are conducted at RUB. Constitutive models for clay developed at CUP and RUB will be enhanced with respect to THM loading paths. The enhanced models are validated and compared based on the performed experiments. Enhanced models will be adopted in numerical simulations of energy piles.


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