FILL PROCESS OF ENCLOSED CAISSON

PURPOSE:To improve the deposit density of fill sand by laying a permeating members on the bottom of a caisson and providing the upper end of a water supply pipe communicating through the lower end to a permeating gap higher than a top plate to mount a valve. CONSTITUTION:Permeating members 11 such as foamed concrete plate are provided on the bottoms of partitioned cells 8 respectively. Then, the lower end of a water supply pipe 12 is inserted in the permeating member 11 and the upper end of the water supply pipe 12 is adapted to project above a top plate 2 to mount a valve 13 on the projecting part. Next, every time fill sand is deposited to a certain height, or in the increase of internal pressure at the last stage of charging, the valve in the water supply pipe is opened to reduce pressure on the bottom of the caissons. Water flow directed downward is gener ated in the fill sand 5 so that permeating pressure acts on the deposited fill sand 5 to improve the deposit density and the stability of the caisson.