| 摘要 |
The invention relates to a device making it possible to fit in tunnels shoring bolts which are substantially longer than the headroom available in the tunnel. It consists of a steel rod (1), bias-cut at one end and welded at the other to a steel cable (2), the other end of which is welded to a steel rod (3), the other end of which is right-hand threaded over 200 mm, a nut (6), is screwed on over 40 mm and, at (5), a spot weld making it possible to fit the nut but preventing it from being unscrewed to premit the working of the anchoring product and the tightening of the nut in the other direction of rotation. The device of the invention is especially intended for shoring tunnels through particularly poor ground. |
