To form a high quality concrete surface for the tunnel zenith section by simplifying its arrangement working and eliminating members for guiding a vibrator and efficiently transmitting the vibration of the vibrator to the surface of a form.
The vibrator 15 is constituted with a long frame 16 long in the peripheral direction of the tunnel and vibration generators 17 at both the ends, and a plurality of wheels 19 are provided on a frame 16. The vibrator 15 is installed on the form 4b through an inspection window 8 at the tunnel zenith section. The vibrator 15 is pulled in a direction of a tunnel shaft line through a wire rope by an electrically operated winch 27. A cable holding device is attached to a form 4b at the side of the winch 27 by the vibrator 15, and a feeder cable of the vibration generator 17 is retained.
MURAYAMA AKIRA
GOTO SHINICHI
FUKUDA CORP