Nippon Concrete Industries Co. Ltd.

Ichiro Tanaka

Koji Nunokawa

Nobuyuki Abe

Masao Manabe

Osamu Watanabe

Masami Tominaga

This invention relates to a method of setting a pile without causing any noise or vibration. A hollow pile is erected along a leader fixed on the ground, a screw auger is inserted through the hollow center of the pile, the screw auger is hung on the leader in such a manner that it can freely move up and down and freely rotate, and the pile is sunk by its own weight as the soil below the bottom of the pile is excavated and the excavated soil is carried above the ground. The present invention further relates to an apparatus for executing the above method. The lower part of the screw auger is constructed in such a manner that it is divided into two parts, inner tube and outer tube, and both tubes can rotate through a certain angle and move up and down in a certain range relatively to each other. Excavating nozzles are disposed at the lower part of the screw auger in such a manner that they can be unfolded at several stages by the relative rotation and the vertical movement of the fluid is directed laterally from the nozzles to enlarge the hole below the pile.

Method of setting a pile without noise or vibration and apparatus

The present invention relates to a process of setting a concrete pile without noise or vibration which is thereby effective to decrease city noises. A concrete pile is sunk into a leading hole substantially concurrently with the progress of the excavation thereof. After the pile has been sunk through a desired distance, another supporting hole is excavated below the pile. A solidifying material, such as cement milk, mortar, or cement concrete including a cement expansion agent of calcium sulfoaluminate system or lime system, is poured into the supporting hole. The solidifying material is expanded within the supporting hole and permeates into the circumferential wall thereof, which is loosened by the excavation, so as to retighten the wall. Therefore, sufficient supporting force can be obtained.

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Kamakura, Japan

Ichiro Tanaka