FORWARD SURVEY DEVICE IN TUNNEL FACE AND FORWARD SURVEY METHOD USING THE SAME

摘要

To provide a forward survey device in a tunnel face capable of directly and visually recognizing a state of a natural ground in front of the tunnel face.SOLUTION: The forward survey device includes: a plurality of transparent tubes 1 successively located in a borehole 41 bored by a casing in a tunnel boring direction; and a camera 2 inserted into a transparent tube 1 for photographing a peripheral wall of the borehole 41 from the transparent tube 1. The forward survey device in the tunnel face is so configured that a conical leading tube 11 is attached to a tip of a lead transparent tube 1, and a rear end of a precursive transparent tube 1 of the plurality of transparent tubes 1 is connected to a front end of a following transparent tube by a connecting tube 3 inserted from both ends.SELECTED DRAWING: Figure 1