Patent GB-1462711-A (GB)
Title: Method for constructing a lining
IPC: E21D11/20
Filed: 1974-02-12
Abstract: 1462711 Tunnel and well linings PONT-A-MOUSSON SA 12 Feb 1974 [19 Feb 1973 31 Jan 1974] 06301/74 Heading E1F Tunnel or well lining panels intended for assembly at site into angularly-staggered abutting rings are themselves assembled off-site from two or more voussoirs, e.g. of cast iron, which are arranged in a jig providing spaced support and bearing points, the gaps between adjacent voussoirs in the jig being filled with weld or a bonding agent which can be injected into the gaps while the voussoirs are in the jig or which can be previously-disposed on the mating areas of the voussoirs. Each voussoir may include a part-cylindrical base 101 (Figs. 10-12) bordered by flanges 102a, b and 103a, b arranged such that the mating flanges of adjacent voussoirs define channels 106, 107, 112a, 112b for receiving the bonding agent, the flanges 102a, b having complementary convex and concave surfaces providing a swivel joint. In other types of voussoir disclosed, the base may be corrugated in the axial direction of the voussoir, or the base edges and flange edges of adjacent voussoirs may be arranged to abut and be welded together by plasma welding. Each lining ring assembled in the tunnels from the panels is completed by a keystone panel whose voussoirs 7, like those in the neighbouring panels, have non-radial flanges 27 (Fig. 9) each intended to abut a like flange 13b of a neighbouring panel to which it is secured by bolts 28 and L-section members 29 each having one limb 30 receiving a bolt 28 at 31 while the other limb 32 projects into slots 33, 34 in the flanges to accept the shear loading in use and prevent fracture of the bolts. Each panel may consist of eight voussoirs arranged in two parallel circumferentially-extending rows, i.e. four per row, and in that case the jig (shown diagrammatically in Fig. 13) may include a part-cylindrical base 115, axial walls 117a, b and circumferential walls 118a, b, provided with spaced support elements 123 and bearing elements 124 each including a ball which is intended to contact the base or a flange of a voussoir and which is carried by an axially-adjustable holder. The voussoirs   119a-d, 120a-d are assembled on the support elements 123 in roughly their required positions, in which positions the clearances between adjacent voussoirs are closed from below by inflatable sealing strips 125 (Fig. 24) supported by the jig base 115, and then the walls 117a, b are pivoted towards each other by rams to closed positions defined by stops, at which stage the wall 118b is moved towards fixed wall 118a by a ram to its closed position, also defined by a stop. At this stage in the construction of a panel, the outermost ends of the clearances between the voussoirs are closed by sealing strips on the walls 117a, b; 118a, b and a profiled beading 127 (Fig. 24) is then laid over the voussoirs to close the clearances from above, a cover 122 finally being placed over the voussoirs to engage beading 127 and cause the latter to urge the voussoirs apart and into contact with the bearing elements 124. The sealing strips 125 are then inflated and, if the bonding agent is not already in place on the voussoirs it is injected into the clearances, the bonding agent eventually being cured by circulating hot air or steam through the jig. The jig can also be adapted, by adjustment of the support and bearing elements, to allow assembly of non- rectangular panels suitable for constructing rings required for use at bends in a tunnel. The voussoirs forming each panel can additionally be bolted together and the joints between adjacent panels at site are sealed by injection of bonding agent after injection of cement outside the lining, the adjacent panels being bolted together. Also disclosed is a jig for making panels each including two voussoirs aligned circumferentially, one circumferential wall being omitted from the jig and the base of the jig being tilted so that the voussoirs tend to move under gravity over the support balls towards one fixed axial wall and the one, fixed circumferential wall, the remaining axial wall being pivotable between open and closed positions. With this jig, instead of using a cover and the profiled beading 127 described above, the clearance between the adjacent ends of the two voussoirs is closed on all sides by a sealing strip encompassed by a four-limbed clamping frame arranged to clamp the strip around the voussoir in overlapping relation therewith. The bonding agent used for assembling panels required for constructing selected lining rings may remain compressible to absorb expansion and contraction.