SPRAYING DEVICE FOR TUNNEL

PROBLEM TO BE SOLVED: To continuously carry out spray while always keeping the spraying device vertical to the spraying surface and keeping it in a constant spraying distance, and to carry out the measurement of spraying thickness in parallel with the spraying operation without interrupting the spraying operation. SOLUTION: This spraying device for a tunnel has a traveling rail surface formed along the circumferential direction of the tunnel in a nearly constant distant distance on the inner side than the circumferential wall surface H of the tunnel, and is made up of a circumferential rail member 3 movable along the longitudinal direction of the tunnel and a spray nozzle holding device 4 mounted on the circumferential rail member 3 and travelable in the circumferential direction of the tunnel along the traveling rail surface. Light wave range finders 5A, 5B for collimating the tunnel wall surface are arranged and fixed respectively in the front and rear positions in the moving direction putting the spray nozzle therebetween viewing from the front with regard to the spray nozzle holding device 4.