SEA-BED FOUNDATION IMPROVEMENT METHOD AND OUTER PIPE FOR CHEMICAL INJECTION

PROBLEM TO BE SOLVED: To provide a sea-bed foundation improvement method and an outer pipe for chemical injection capable of preventing the outer pipe for chemical injection installed underwater from being damaged by external environments such as wave motion and improving the workability of soil improvement work. SOLUTION: The outer pipe 1 is constituted of a rigid pipe 2 and a flexible pipe 3. With the rigid pipe 2 of a lower end section installed in a sea-bed foundation 19, its upper end part is extended above the water, and at least part of its section protruding from the sea-bed foundation 19 and installed underwater is made of the flexible pipe 3. An inner pipe 7 having a discharge opening in its circumferential wall is inserted in the outer pipe 1. A soil improvement chemical G supplied through the inner pipe 7 is injected from the discharge opening into the sea-bed foundation 19 through an injection opening 2a formed in the outer circumferential surface of the outer pipe 1 positioned in the sea-bed foundation 19. COPYRIGHT: (C)2011,JPO&INPIT