GB582725A - Improved means for driving and lining tunnels - Google Patents

Abstract

582,725. Tunnels. WILSON, A. D. G. Feb. 3, 1944, No. 2010. [Class 85] In driving and lining tunnels, rolled steel sections are built up into ribs of circular or other form on which removable arched shuttering plates are supported by spring clips on the shuttering plates co-operating with cover-plates wider than, and secured to, the inner flanges of the rib sections, which shuttering plates support the concrete of the lining as it is positioned. In a circular tunnel driven by a double shield as in Specification 580,047, circular ribs are built up of arcuate I-beams 1 connected as by fish-plates 2 ; a cover-plate 3 is bolted to, and is wider than, the inner flange of each rib, the plates 3 being adapted to support removable flexible arch plates 5 furnished with spring clips 6 engaging the plates 3. Each arch plate &c. 5 has on one edge a welded strip 5<x> adapted to overlap the adjacent plate 5. Before a new rib 1 is positioned and the rams 8 for advancing the shield are retracted, wedges 10 are inserted into holes 11 in the tail 9 of the trailing shield and bear against the previous rib 1 ; further wedges 12 are inserted between said previous rib 1 and the tail 9, the wedges preventing rearward movement of the trailing shield under pressure of the rams which advance the forward shield, and also preventing forward movement of said rib 1 under pressure from the deformed arch plates and wet concrete in the previous section. The new rib 1 is then positioned by the rams of the trailing shield, the arch plates 5 are inserted and concrete filled in behind the arch plates; at the roof of the tunnel, one or more apertured arch plates 13, Fig. 3, are inserted which are provided with a sliding plate 14 carrying a length of hose 15 through which the concrete filling is completed, the apertures being then closed by further sliding plates 16. When rams 8 are operated to advance the trailing shield, they also act through the forward ring 1 to flex the arch plates &c. 5 and force the new concrete into the space previously occupied by the tail of the trailing shield.