| 摘要 |
PURPOSE:To cause a footing to be lowered to a position deep in a ground, by a method wherein an enclosed space is formed with a leg column, having a hollow part, or a skirt, attached around the footing, and a sea bottom, and high pressure water is fed through the closed space into the hollow part. CONSTITUTION:A leg column 12 of a off-shore working platform is seated on a sea bottom, and an enclosed space 32 is formed with the leg column 12, a footing 14, and a skirt 26. A valve 38 of a means 34 through which the inside and the outside of the space 32 are intercommunicated, and a valve 40 of a means 36, through which the space 32 and a hollow part 28 of the leg column 12 are intercommunicated, are opened. Water at the outside flows in the space 32 through a pipe 34a and branch pipes 34b, 34c to disturb a sedimentary layer H, and a component, with which the sedimentary layer H is formed, is mixed with water. The component, mixed with water, is fed to the leg column 12 and the hollow part 28 through a pipe 36, the sedimentary layer H below the footing 14 is removed, and the footing 14, i.e., a working platform is gradually lowered. |
