Abstract
Submerged soils may be considered as an unsaturated porous medium containing gas, water and solids. By using a three-phase model, the mechanical behaviour of such soils can be described by an extended consolidation equation in order to calculate transient pore water pressures, induced by external pressure changes. Microscopic gas bubbles embedded in the pore fluid of the soil skeleton may play a key role in soil behaviour due to the increased gas-water mixture compressibility. Pressure changes applied on such unsaturated submerged soils may cause soil structure deformations such as heaving, settling or even fluidisation. Rapid external pressure reductions such as excavations, draw down loading or ground water level lowering are followed by a delayed pore water pressure propagation. Transient pore water pressures may therefore cause embankment sliding, hydraulic failure and unacceptable deformation. Case studies concerning geotechnical applications are presented. Results from numerical simulations based on Biot’s consolidation equation are compared with computations based on Richards equation. The results are discussed towards formulation of protection measures in order to improve stability requirements.
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Köhler, HJ., Montenegro, H. (2005). Investigations regarding soils below phreatic surface as unsaturated porous media. In: Schanz, T. (eds) Unsaturated Soils: Numerical and Theoretical Approaches. Springer Proceedings in Physics, vol 94. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-26737-9_11
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DOI: https://doi.org/10.1007/3-540-26737-9_11
Publisher Name: Springer, Berlin, Heidelberg
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