| 摘要 |
PURPOSE:To prevent soil from dropping in a soil reservoir located at the lowermost part of a deep well, by a method wherein, by the use of casing, processed so as to be served as a strainer, the deep well is formed, and a float cover for soil reservoir is located to the interior of the casing. CONSTITUTION:A support metal 7 is secured to the inner surface of a casing 2 which is formed such that a wire net 3 is wound around the outer surface of a steel pipe, processed so as to be served as a strainer through provision of slits 2a throughout the overall length. Further, a float cover 6 is placed on the metal 7, and a form 8 for holding a soil reservoir space is secured to the float cover 6. Thereafter, the casing 2 is inserted into a vertical hole 1, gravel 4 is charged into the vertical hole 1 therearound to fill it with the gravel. An underwater pump 5 is then placed on the form 8 and water is drained, resulting in lowering in a water level in a ground under excavation and deposition of soil in water on the float cover 6. This eliminates formation of a shallow sump at each excavation stage, and enables to perform a safe and efficient work. |
