PURPOSE: To obtain a waterproof sheet for tunnel extended along the surface in a tunnel in order to lead the ground water oozed out from a natural ground to both side ditches in the tunnel, and to prevent the dropping of the waterdrops in the space in the tunnel; and to extend such a waterproof sheet along the surface in the tunnel.
CONSTITUTION: On the wall surface of the primary concrete 3 formed to a natural ground in the excavation hole of a tunnel, a water flow buffer 4 is abutted, and concrete nails 5 are hit in the water flow buffer 4 and the primary concrete 3 so as to fix the water flow buffer 4 to the primary concrete 3. A water cut-off sheet 6 is superposed to direct the fixed sheet 7 of the water cut-off sheet 6 in the peripheral direction of the tunnel excavation hole 1, and to contact the water cut-off sheet 6 to the water flow buffer 4. Under the condition where the part of the water cut-off sheet 6 contacting with an aluminum foil 9 is pressed strongly to the water flow buffer 4 by the inductor 12 of an electromagnetic induction heater 11, the electromagnetic induction heater 11 is operated so as to generate an electromagnetic induction heating between the inductor 12 and the aluminum foil 9, and the water cut-off sheet 6 and the fixed sheet 7 are fused, so as to fuse the water flow buffer 4 and the fixed sheet 7 integrally each other.
SHINTANI KAZUNARI
KATO TAKEHISA
