CAISSON METHOD

PURPOSE:To make smooth settlement possible when settling a caisson into ground by making air bubbles, formed by foamed liquid containing foaming agent, ejected under pressure together with jet stream and by making the air bubbles mixed in the ground. CONSTITUTION:To the lower end of a reinforced concrete caisson 10, a cutting edge 12 is formed and, at the same time, jet stream supply passages 20 and air bubble supply passages 22 are installed at intervals in the peripheral direc tion at the inside of the caisson body 14. A pump 26 for applying pressure to the water in a water tank 24 and a foaming device 28 are connected respec tively to the upper ends of the passages 20 and 22. The lower ends of the passages 20 and 22 are connected to nozzles opened to a friction cut 16 of the caisson. The air bubbles B and the jet stream A are ejected under pressure through the nozzles 32 to the inside of ground 18, and friction force between the outer periphery of the caisson 10 and the ground 18 is decreased thereby. Therefore, settlement of the caisson can be made smoothly.