PURPOSE: To expand and close in automatic mode and prevent lining leakage by pivoting each jack with a case type support mechanism which extends in the axial direction of the rear side central part inside a shield propulsion main body for each movable segment inner form.
CONSTITUTION: Prior to the installation of a tunnel lining 5, jack rods 22a and 23a of each of jacks 22 and 23 are extended and seal rubbers 17 and 18 of a movable segment inner form 16 are pressed against the lining 5, thereby expanding. Then, after the installation lining 5 is cured, a propulsion jack 13 is operated so as to move the jack rod 13a backward and advance a movable propulsion plate 14 as well so that reaction force may be obtained for the lining 5. Then, the jacks 22a and 23a are shortened in a hiding manner between a fixing outer form 2 and the seal rubber 18 of the movable segment inner form 16 simultaneously in the radial direction one by one, thereby closing the inner form 16. Then, a shield propulsion main body 1 constructs a continuous straight and curved tunnel by executing intermittent filling work while repeating constant pulling and driving work and expansion and closing work of the inner form 16.
OTAKE MASASHI
SAKURADA TAKAYOSHI
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