Changes in permeability of sand during triaxial loading: effect of fine particles production
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Various mechanisms can affect the permeability of dense unconsolidated sands: Volumetric dilation can lead to permeability increase, whereas strain localization in shear bands may increase or decrease the permeability depending on the state of compaction and on the level of grains breakage inside the band. To investigate these various mechanisms, an experimental study has been performed to explore the effect of different factors such as grain size and grain shape, confining pressure, level of shear, stress path, and formation of one or several shear bands on the permeability of dense sands under triaxial loading. The experimental results show a reduction of permeability during the consolidation phase and during the volumetric contraction phase of shear loading, which can be related to the decrease of porosity. The experimental results also show that, depending on the confining pressure, the permeability remains stable or decreases during the volumetric dilation phase despite the increase of total porosity. This permeability reduction is attributed to the presence of fine particles, which result from grains attrition during pre-localization and grains breakage inside the shear band during the post-localization phase.
KeywordsFine particles production Permeability Sand Shear band Stress path
The authors gratefully acknowledge TOTAL for supporting this research. They wish also to thank Irina Andria-Ntoanina, Sara Assandi and Pierre-François Marty for their assistance in the experimental program.
- 3.Crawford BR, Gooch MJ, Webb DW (2004) Textural controls on constitutive behavior in unconsolidated sands: micromechanics and cap plasticity. Proceedings of 6th Int. Conf. North American Rock Mechanics Symposium (NARMS). American Rock Mechanics Association, ARMA/NARMS 04-611Google Scholar
- 6.Nguyen VH (2012) Compaction des roches réservoirs peu ou non consolidées: impacts sur les propriétés de transport. Ph.D. thesis, Université de Cergy-Pontoise, FranceGoogle Scholar
- 7.Olson JE, Yaich E, Holder J (2009) Permeability changes due to shear dilatancy in uncemented sands. Proceedings of US Rock Mechanics/Geomechnics Symp. 28th June–1st July, Asheville, NC, USGoogle Scholar