Impact of microstructure on the hydraulic conductivity of undisturbed and artificially prepared smectitic clay

摘要

The microstructure controls most physicalproperties of clays. This is obvious when comparing naturalsmectitic clay and clay prepared by drying, grinding andcompression of air-dry powder. The hydraulic conductivity of theartificially prepared clay is higher than that of the undisturbed.Natural clay. If the latter clay is percolated with distilled waterand Ca-rich water, the difference in conductivity is obvious,while percolation of the natural clay with these solutions doesnot yield a very dramatic change. This is because themicrostructure of the natural clay is very homogeneous, while theartificially prepared clay preserves the high density of the powdergrains while the gels in the voids between the grains are soft.