Present Status of Drilling Technology for Groundwater Ressources Development of Japan
1972 Volume 81 Issue 5 Pages 344-348
Details
1972 Volume 81 Issue 5 Pages 344-348
It was 1912 that the water well drilling by means of a mechanical method was done for the first time in Japan. Since then, various kinds of drilling machines have been designed and developed.
1. Construction methods for water well
The purcussion method has gained recently a very high productivity of drilling, e.g.5-6 folds as much drilling speed as that of 20 years ago, by means of using tubular bit '.
2. Screens
Many types of screens with various kinds of structure are now being manufactured, especially, the one with a high opening ratio is now widely used.
3. Pumping
The main line of pumps for water wells are electro-submersible pump, with which safe-yield and conditions of aquifers are examined by means of draw-down test and recovery test in order to secure a rational discharge of groundwater.
