Enlarging bottom anchor construction method

摘要

PROBLEM TO BE SOLVED: To increase fixing strength in an anchor fixing length section. ;SOLUTION: An anchor pit 12 is drilled once up to the predetermined depth of anchor overall length L0 in the outer pipe 22-0 of a drilling pipe 22. The outer pipe 22-0 is drawn up and held by an anchor fixing length section L1 while an improvement agent 30 is injected at high pressure in the peripheral surface direction of the anchor pit 12 by the inner pipe 22-I of the drilling pipe extended from the outer pipe. The inner pipe 22-I is extracted from the outer pipe 22-0 and recovered, the outer pipe is pushed into the place of the bottom section of the anchor pit 12 again, and a grout material is infected through the outer pipe while an anchor tendon is inserted.;COPYRIGHT: (C)1998,JPO