Abstract
It has been desired to establish a simple and appropriate method for lining canals and ditches for irrigation and drainage.
Attention was paid to the peculiar concretion phenomenon of soils by Polyvinylalcohol, and several experiments were made on the application of PVA-H, a kind of Polyvinylalcohol Products, for such lining.
After sprinkling PVA-H solution of different concentrations over soil surface, tests were made on the treated soil layer as to its adhesion to the original soil layer, the prevention of failure along craks, its water-tightness And its water-stability.
Two kinds of sandy loam were used to test these probrems. The results are as follows:
1. The adhesion of the treated soil layer to the original soil layer may be considered to depend on the concentration of solution and the depth of its infiltration; data show that the dilute solution under 296 brings good result, and the concentrated solution of about 3% or more causes a separation of the treated soil layer from the original soil layer.
2. Cracks develop owing to the shrinkage characteristics. The characteristics can be improved by the treatment with PVA-H solution. However, there is little difference among the effects by variously concentrated solutions.
3. In order to prevent from the percolation of water, it is required to treat with 3% solution of PVAH, and similar impervious layer can be obtained by repeated sprinkling of more dilute solutions.
4. The water-stability seems to be good except to mechanical shocks. These data seem to show that repeated sprinkling of such a dilute PVA-H solution as 1-2% brings the, most favorable condition for lining canals and ditches.
