PURPOSE: To surely perform the drilling work regardless of the soil by extending load jacks to both sides, stretching facing reaction walls to the outsides from openings of both side all blades, and extending a propelling jack while being pressed to side wall faces.
CONSTITUTION: Pressure walls 4 on both sides are arranged at the foremost position in an opening 5 by a return jack 8 in advance, individual load jacks 6 are extended to both sides to press the reaction wall 4 to drilling side wall faces. Under this condition, a propelling jack 7 is extended, a hinge member 7a is brought into contact with the reaction receiving member 4a of the reaction wall 4 to press it, and a main body 1 is advanced by the reaction by one propulsion stroke. When the main body 1 is advanced, the load jacks 6 are shrunk, the reaction wall 4 is stored in the opening 5, the propelling jack 7 is shrunk, the return jack 8 is extended, the reaction wall 4 is slid to the foremost position in the opening 5, this timbering is constructed behind the main body 1. Spaces on both front and rear sides of the reaction wall 4 are invariably shielded by a shutter wall 21, the infiltration of drilled sediment is prevented.
TAKAYORI MAKOTO
HATANO TOMIO
HAMADA KENTARO
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