Multiscale modeling of geomaterials subjected to environmental loads

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The proposed research is related to modeling of mechanical and hydraulic response of geomaterials subjected to environmental influences. It is recognized that climate change will have a direct impact on a wide range of physicochemical processes in soils thereby modifying their microstructure and affecting their properties. Therefore, the focus in this research is on the response of soils to extreme weather conditions, viz. moving freezing front and a heavy rainfall. The major topics that will be addressed include: (i) modeling of the mechanical response of frost-susceptible soils, (ii) modeling of the chemo-mechanical interaction in soils due to increased rainfall and (iii) influence of evolving microstructure on the hydraulic/strength properties of soils.**Re.(i) Frost heaving and thawing is a major cause of damage to infrastructure and landforms (e.g. debris flow) in regions of seasonal frost. The primary objective of this research will be to develop a framework for describing the deformation process in both in-situ frozen soils as well as soils containing ice lenses. This framework will be employed to model the effects of frost heave on the integrity of oil/gas pipelines.**Re.(ii) Intense precipitation often leads to a loss of stability of geotechnical structures, in particular that of natural slopes and embankments in cohesive soils. Specification of properties of these soils is difficult as it involves a complex system of mineralogical and chemical factors. The approach implemented here will be based on a framework of chemo-plasticity. The governing equations describing the transient hydro-chemo-mechanical coupling will be applied to examine the stability of slopes subjected to a rainfall. **Re.(iii) The environmental loads, viz. temperature and precipitation, can significantly alter the microstructure of the material, which often leads to anisotropy at the macroscale. The main objective of this work will be to introduce tensor-valued descriptors of material fabric, establish appropriate evolution laws for these measures and incorporate them in a macroscale framework. **The results of research will contribute to both fundamental knowledge as well as practical engineering aspects.****************