The sloughing of unconsolidated river sand (porosity about 50%, permeability 45 darcys) was measured with several kinds of liquids. These were water, CMC solutions, bentonite dispersions and bentonite-CMC dispersions.
The results obtained were as follows:
1. Water has a severe sloughing effect upon the unconsolidated sand.
2. Bentonite dispersions of high concentration (8%) reduce the amount of sloughing considerably but are not completely effective. When CMC is added to this dispersion, it becomes completely effective but is not economical.
3. CMC solutions are fairly effective in preventing sloughing but the effectiveness varies with type of the CMC.
4. When the most effective type of CMC is used, the concentration to prevent sloughing is comparatively high (0.1-0.5%), so that these CMC solutions are not economical.
5. Bentonite dispersions of low concentration (2%) plus CMC (0.07%) are both effective in preventing the sloughing and are economical.
6. Sands those were previously wet have a stronger tendency to slough than do dry sands.
7. Sands which contain dispersed clay have a weaker tendency to slough than do sands not containing clay.
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