METHOD FOR PREVENTING BACKING OF PROPULSION PIPE

摘要

PROBLEM TO BE SOLVED: To provide a backing preventive method for efficiently and surely preventing a backing force from working on a faceplate during the propulsion of a shield machine having a closed faceplate. SOLUTION: In this method for preventing a propulsion pipe 9 from being pushed back by a force opposite to the direction of propulsion, produced by the pressure of muddy water or underground water which works on the faceplate of a shield machine during initial propulsion, a plurality of insert anchors 6 are buried into symmetrical positions on both side wall faces behind the propulsion pipe 9, and after propulsion of one propulsion pipe 9 is complete, bolts 5 are driven into the insert anchors 6 in such a manner that each bolt 5 projects by a predetermined length from the side wall face. Backing-preventive metal fittings 1 comprising plates with laterally projecting support arms 3 are secured in place by means of the bolts and a fixed frame 4 provided to abut the support arms 3 prevents the propulsion pipe 9 from being pushed back.