| 摘要 |
PURPOSE:To form a strong sand pile by a method in which a vibrator is provided in a vertically movable manner through an air spring on an outer casing, the uper end of an inner casing is fixed to the vibrator, and the lower end of the inner casing is hung down in the outer casing. CONSTITUTION:A vibrator 20 is actuated, an outer casing 1 is penetrated into the ground G, and sand is charged into the outer casing 1 from a hopper 11. Air in an air spring 4 is injected or exhausted to an extent that the stopper 74 of a guide pipe 73 is not coupled with a fixed plate 70, whereupon the ground G around the outer casing 1 to vertically move the inner casing 3, but not by the vibrator 20, is protected without being stirred, and sand in the outer casing 1 is compacted by the inner casing 3 and also pushed out of the tip of the outer casing 1. At the same time as the inner casing 3 moves vertically, a pulling means 6 is actuated to gradually pull out the outer casing 1. |
