RAPID EXECUTION OF TUNNELING AND EXCAVATOR THEREFOR

PURPOSE:To shorten term of works for tunneling in a mountain by a method wherein free face cutting devices, capable of moving in the vertical, the forward and backward and the rightward and leftward directions, are installed in two stages in an excavation section of an excavator that is made in shield structure, and erectors for erection and demolition of forms are provided to the rear side thereof. CONSTITUTION:An excavator is brought in a tunnel and excavation is started by combination of methods in vertical cutting with jacks 7b of free face cutting devices 7, in cutting by forward and backward movement in sliding in holding members 8 and in cutting by rightward and leftward movement in sliding in support stands 9, and front ends 7a of the cutting devices 7 are moved toward a facing 6. A form 14 is then brought in with an erector 15 and is erected with a gap provided between the excavated face and the form, and concrete is cast into the gap with a press ring for sealing fitted to the gable side of the tunnel. Then tail void is filled being pressurized with a press jack 23 and the excavation is progressed further with a shield jack 24 that is extended on reaction taken on the form 14. Thereby efficiency in execution of work can be improved.