Smectites swelling volumes

Table 8.3. Swelling Volumes of Metal-Exchanged Smectites in Water (cmVs)...

The increase of soil volume from clay swelling in the field has important practical consequences, particularly in soils containing smectites. The extent of this problem depends very much on the nature of the exchange cation, as illustrated by the swelling volumes of smectites reported in Table 8.3. These results emphasize the management problems likely to be encountered with soils that are sodic. 

Lower-permeability sands should be treated with lower acid volumes, because of the increased sensitivity to damage caused by the treatment. Also, if a formation contains high clay content, especially the swelling variety (e.g., smectite or illite-smectite), volumes may need to be reduced further. 

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