GB1510401A - Tunnel linings - Google Patents

Abstract

1510401 Tunnels &c EDMUND NUTTALL Ltd 2 Dec 1976 [29 Jan 1976] 3609/76 Heading E1F A tunnel lining ring is made up from arcuate concrete segments 11, 12 having aligned circumferential recesses 16 on their outer faces and a plurality of tie bars 31 located in the recesses 16 and connected together to form a circumferential hoop terminating with both ends in a key segment 13. As described each segment 11, 12 is formed with two recesses 16 and two hoops are provided for each ring. The lower segments 11 are provided with recesses 16 having enlarged ends 17 to accommodate connector members 34 (Fig. 2) for the tie bars. Three tie bars 31 are provided for each hoop, the lowermost tie bar having left hand threads at its ends and the uppermost tie bars 31 having right hand threads. Each connector 34 consists of a sleeve having a right hand thread at one end and a left hand thread at the other end, the tie bars thus being joined by rotating the connectors. The key segment 13 (Fig. 8) is provided with recesses 16a and openings 25 which allow the tie bars to be tensioned by nuts 32 bearing on metal plates 33. Filler blocks 29 can then be fixed in the holes 25 by rods 28 to provide a smooth inner surface to the lining. Adjacent rings are aligned by dowels (not shown) located in holes 21 and are sealed to each other by a sealing ring (not shown) located in groove 22. After assembly grout is injected into grouting rebates 19 and into the space between the earth wall and lining, thus filling the recesses 16.