GB1275268A - Improvements in tunnel linings - Google Patents

Abstract

1275268 Tunnel linings WILLIAM F REES Ltd D F REES and J B GARNETT 30 June 1970 [11 July 1969] 35088/69 Heading E1F A method of lining a tunnel comprises using radially flexible rings, or rings having radially flexible major segments, passing the rings or major segments through an installed tunnel lining, flexibly expanding the rings or major segments to conform with the tunnel lining and, in the case of a major segment, inserting a minor segment to complete the ring. In one described method a flexible split ring 14, Fig. 2, is held contracted by steel bands 16 to enable the ring to be passed lengthwise through lining 11. Alternatively, Fig. 3, flexible complete ring 20 is deformed by jack 21 to enable it to be passed sideways through the lining. In a further described method, Fig. 5, major flexible ring segments 30a are held contracted by steel bands 32. Rigid minor segments 31, which may be of concrete to form an invert, are inserted after segments 30a have been expanded. The expanded segments are moved to abut the installed lining by the tunnelling shield rams. Mild steel segments may be used, whose joints may be welded. Sections made of resin-bonded materials, or plastics such as unplasticised P.V.C., may be used, and their joints may be bonded. Longitudinal joints may be sealed with joint strip 17, Fig. 2. Circumferential joints may be of the spigot and socket type, and may be bonded or fitted with rubber O rings.