TUNNEL LININGS

Abstract: A method of assembling a tunnel lining formed of concrete segments (1, 2) joined together at their side edges to form annually together with interengaging joining means (3, 8-17) which are interengaged by sliding one segment relatively to the other. The joining means includes a recess (5) in an edge of one segment, the recess containing a channel member (8) with inturned flanges (9) defining a slot in which a screw threaded bolt (15) can be slid. The bolt is screwable into the adjacent segment and once the segments are located in the desired position, the bolt is tightened to clamp the segments together, the bolt having a head (16) which abuts the inner surfaces (10) of the flanges (9). The method also includes joining segments by inserting dowels in sockets of adjacent segments, the dowels having radially extending fins (24) of resiliently deformable material of greater width than the sockets (21) so that the deformed fins are caused to engage the inner surfaces of both opposed sockets to hold the adjacent annuli together.

Description: This invention relates to linings for tunnels which are built up of concrete segments, the segments being connected together edge-to-edge to form annuli and the end edges of the annuli being joined together to form a continuous lining for the tunnel. This invention is especially but not exclusively intended for use when assembling a tunnel lining having a smooth inner surface. The invention is intended to provide a method of assembling a tunnel lining which is simple and easy to use when working in a confined space inside a tunnel, in which both the segments of an annulus and adjacent annuli are positively joined together so that the lining can resist internal hydrostatic pressure, and in which the assembled lining has a substantially smooth inner surface with no connecting elements extending radially inwardly of the lining. An example of the prior art shown in GB-A-2,092,644 where arcuate concrete segments of a tunnel lining are joined together by means of a recess in a segment edge and a pair of abutment members projecting into the recess to define a constriction therein, the abutment member forming a pair of abutment surfaces facing inwardly of the constriction. A screw-threaded bolt is provided in an adjacent segment and when the segments are positioned edge-to-edge with the bolt inserted in the recess the segments can be moved relatively to each other so that the bolt head engages the abutment surfaces. The recess is accessible from inside the lining to allow the bolt head to be tightened. NL-A-99,326 discloses a similar concept and in this case a U-channel type of insert is provided with inturned flanges in the concrete for joining the concrete segments. According to one aspect of the present invention, there is provided a method of assembling a tunnel lining formed of concrete segments joined together at their side edges to form annuli and at their end edges to join the annuli together, the opposed side edges of adjoining segments of an annulus having interengaging joining means which are interengaged by sliding one segment relatively to the other in the longitudinal direction of the tunnel; said interengaging joining means comprising a recess in the side edge of one segment containing an insert comprising a channel member having two inturned flanges defining a slot in the side edge and the side edge of the adjoining segment being provided with a screw-threaded bolt screwable into the segment and projecting outwardly of the segment edge, and as one segment is slid in the longitudinal direction of the tunnel the bolt within said recess moves to a position between said flanges, the bolt having a head which abuts the inner surfaces of said flanges to clamp the segments together when the bolt is tightened by screwing into its segment, characterised in that said bolt has a portion located on its shank between the head and the screw-threaded portion, which portion is for receiving a spanner to screw the bolt into a screw-threaded socket in the adjoining segment, the bolt being dimensioned so that the bolt shank between said portion and said head passes through said slot defined by said flanges, whereas the head is wider than said slot. It will be appreciated that the present invention allows the recess containing the insert to be comparatively shallow and to be provided partly in both of the adjoining segments. According to a second aspect of the invention, there are provided tunnel lining concrete segments for joining together at their side edges to form an annulus, the intended opposed side edges of adjoining segments of the annulus having interengaging joining means which are interengaged by sliding one segment relatively to the other in the longitudinal direction of the tunnel; said interengaging joining means comprising a recess in the side edge of one segment containing an insert comprising a channel member having two inturned flanges defining a slot in the side edge and the side edge of the adjoining segment being provided with a screw-threaded bolt screwable into the segment and projecting outwardly of the segment edge, the bolt having a head which abuts the inner surfaces of said flanges to clamp the segments together when the bolt is tightened by screwing into its segment, characterised in that said bolt has a portion located on its shank between the head and the screw-threaded portion, which portion is for receiving a spanner to screw the bolt into a screw-threaded socket in the adjoining segment, the bolt being dimensioned so that the bolt shank between said portion and said head can pass through said slot defined by said flanges, whereas the head is wider than said slot. The end edges of the segments of adjacent annuli can contain opposed sockets of substantially uniform cross-section, the sockets containing dowels having radially extending fins of resiliently deformable material of greater width than the sockets and extending into the opposed sockets so that after insertion of the dowels in the sockets of an annulus and sliding of a segment of an adjacent annulus in the longitudinal direction into abutment therewith the finned dowels retaining the segments of the adjacent annuli together. The fins may be integral with the dowels and formed of a resilient plastics material. As they are inserted in the sockets the fins are deformed elastically so that they are inclined with their outer edges abutting the side of the socket to resist withdrawal of the dowel from the socket. As both ends of the dowel are engaged within opposed sockets of the adjacent segments, the finned dowels hold the segments (and thus the annuli formed of the segments) together. The sockets are simple holes, generally but not necessarily of circular cross-section, formed in the segment edges. They may be formed when the segments are cast and do not generally require any lining element. The end edges of tunnel lining segments are commonly provided with such sockets for other reasons. The interengaging joining means of the side edges of the segments may be of a type described in British Patent 2092644. For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is an end view of an annulus for a tunnel lining, Figure 2 is a cross-section of a tunnel lining made up of annuli according to Figure 1, Figure 3 shows a recess formed in a side edge of a segment of an annulus of Figure 1, Figure 4 is an edge view of the recess of Figure 3, Figure 5 shows the side edge connecting means of the segments of the annulus of Figure 1, Figure 6 shows an insert, and Figure 7 a bolt, used in the connecting means of Figure 5, Figure 8 shows a dowel for connecting the end faces of segments of adjacent annuli, and Figure 9 shows connection of segments of adjacent annuli using the dowel of Figure 8. As shown in Figure 1, an annulus for a tunnel lining is made up of concrete arcuate segments 1, an invert segment 1A and a key segment 2 joined together side-by-side. Adjacent annuli are joined together side-by-side to form a continuous watertight concrete lining for a tunnel as shown in Figure 2. The side edges of adjacent segments of an annulus are joined together by joints indicated generally as 3 and the annuli are joined together by joints 4. The side and end edges are orthogonal. One of the side-to-side joints 3 is shown in Figures 3 to 7. The side edge of one of the adjoining segments is provided with a recess 5 which is elongate in the longitudinal direction of the tunnel lining. The recess is provided with a steel insert member 7 which comprises a generally U-shaped channel member 8 having a pair of inturned flanges 9 defining a slot capable of receiving the shank of a threaded bolt with a bolt head, of greater width than the slot, positioned within the channel member, so that on tightening of the bolt the bolt head may abut the rear surfaces 10 of the flanges. The base of the U-shaped channel member is welded to a stem 11 having an enlarged base 12. The channel member is cast into the recess, as shown in Figure 5, and is held firmly in place by the stem 11 and base 12. As shown in Figures 3 and 4, the channel member occupies the central part of the recess and the head of a bolt may be inserted in the recess at its ends which are not occupied by the channel member. The side edge of the adjacent segment has a recess 13 opening into the tunnel lining interior and an internally screw-threaded steel socket 14 cast into the concrete. Socket 14 receives the end of a screw-threaded bolt 15 having a circular head 16 and a portion 17 which may be hexagonal to receive a spanner for screwing the bolt into the socket. The bolt is dimensioned so that the bolt shank between the hexagonal portion and the head may pass through the slot between flanges 9 whereas the head is wider than the slot. When adjoining segments of an annulus are joined together the segments may be positioned edge-to-edge with the bolt head of one segment inserted in the end of a corresponding recess of the other segment. One segment may then be moved in the longitudinal direction of the tunnel lining so that bolt head 16 moves to within the insert 8, its shank being between flanges 9. The hexagonal part may then be rotated, using a spanner applied from the inside of the tunnel through recess 13, to screw the bolt into socket 14 and tighten head 16 against the rear flange surfaces, thus clamping the adjoining segments together. After assembly of the lining, the recesses may be filled with cement or other filling material to provide a smooth inner surface for the tunnel lining. The joints 4 used for joining the end edges of the segments of adjacent annuli together are shown in Figure 9. The adjoining segment edges are provided with sockets 21 which may be simple holes of uniform circular cross-section formed in the segment edge on casting. The segments are held together by dowels, shown separately in Figure 8, comprising a cylindrical body 22 having tapering ends 23. Body 22 has radially projecting integral fins 24. The dowel is made of elastically deformable plastics material and the body has a diameter slightly less than the diameter of holes 21 but the fins have an external diameter greater than that of the hole. When the dowel is inserted in the hole the fins form an interference fit with the surrounding concrete and the fins are deformed on insertion to resist withdrawal of the dowel from the hole. Thus, when the segments are joined together as shown in Figure 9 the dowel holds them together. When an annulus is assembled within a tunnel to be lined, the invert segment having recesses 5 on both its side edges is first located and the adjacent segments, having bolts on one side edge and recesses on the other, are then located with their bolt heads in the recesses of the invert segment and slid longitudinally into position so that their bolt heads are behind the flanges 9. The adjoining segments of the annulus are fitted in the same way and finally the key segment, opposite the invert segment is fitted to complete the annulus. The key segment has bolts on both of its side edges to engage the corresponding recesses in the adjacent segments. Before assembling a segment in this way, the sockets 4 of the segments of the preceding annulus are fitted with finned dowels 22, extending into and outwardly of the sockets. The dowels are tapered at their ends to facilitate alignment with the sockets and the distance by which they are inserted, generally by tapping with a hammer, is not critical provided that the fins engage the wall of the socket. Invert segment 1A of the annulus is then located adjacent the invert segment of the preceding annulus, and applied to the dowels extending from the preceding annulus as shown in Figure 8. The adjacent segments are then located at a forward axial position with their bolts 15 extending into the sockets of the invert segment, and slid longitudinally towards the preceding segment so that the bolts move to between flanges 9 and their sockets engage the dowels extending from the preceding annulus. The whole annulus is assembled in this way, and after tightening of bolts 15 the recesses 13 may be filled with cement.

Claims: 1. A method of assembling a tunnel lining formed of concrete segments (1) joined together at their side edges to form annuli and at their end edges to join the annuli together, the opposed side edges of adjoining segments of an annulus having interengaging joining means (3, 8-17) which are interengaged by sliding one segment relatively to the other in the longitudinal direction of the tunnel; said interengaging joining means comprising a recess (5) in the side edge of one segment containing an insert comprising a channel member (8) having two inturned flanges (9) defining a slot in the side edge and the side edge of the adjoining segment being provided with a screw-threaded bolt (15) screwable into the segment and projecting outwardly of the segment edge, and as one segment is slid in the longitudinal direction of the tunnel the bolt within said recess moves to a position between said flanges, the bolt having a head (16) which abuts the inner surfaces (10) of said flanges (9) to clamp the segments together when the bolt is tightened by screwing into its segment, characterised in that said bolt has a portion (17) located on its shank between the head (16) and the screw-threaded portion (15), which portion (17) is for receiving a spanner to screw the bolt into a screw-threaded socket (14) in the adjoining segment, the bolt being dimensioned so that the bolt shank between said portion (17) and said head (16) passes through said slot defined by said flanges (9), whereas the head (16) is wider than said slot. 2. A method according to claim 1, wherein the end edges of the segments of adjacent annuli contain opposed sockets (21), the method further comprising inserting dowels in the sockets of a segment, and sliding a segment in the longitudinal direction of the tunnel so that its joining means interengage with those of an adjoining segment of the annulus and its end edge abuts a segment of the adjacent annulus with the dowels extending into the opposed sockets of the abutting segments. 3. A method according to claim 2, wherein the dowels have radially extending fins (24) of resiliently deformable material of greater width than the sockets (21) and the fins, which become deformed, are caused to engage the inner surfaces of both opposed sockets to hold the adjacent annuli together. 4. A method according to claim 2 or 3, wherein the ends of the dowels are tapered. 5. A method according to claim 2, 3 or 4, wherein the dowels are of plastics material. 6. A method according to any one of claims 2 to 5, wherein the sockets in which the dowels are inserted are unlined holes in the concrete of the segments. 7. A method according to any of claims 2 to 6, wherein the sockets (21) are of substantially uniform cross-section. 8. Tunnel lining concrete segments for joining together at their side edges to form an annulus, the intended opposed side edges of adjoining segments of the annulus having interengaging joining means (3, 8-17) which are interengaged by sliding one segment relatively to the other in the longitudinal direction of the tunnel; said interengaging joining means comprising a recess (5) in the side edge of one segment containing an insert comprising a channel member (8) having two inturned flanges (9) defining a slot in the side edge and the side edge of the adjoining segment being provided with a screw-threaded bolt (15) screwable into the segment and projecting outwardly of the segment edge, the bolt having a head (16) which abuts the inner surfaces (10) of said flanges (9) to clamp the segments together when the bolt is tightened by screwing into its segment, characterised in that said bolt has a portion (17) located on its shank between the head (16) and the screw-threaded portion (15), which portion (17) is for receiving a spanner to screw the bolt into a screw-threaded socket (14) in the adjoining segment, the bolt being dimensioned so that the bolt shank between said portion (17) and said head (16) can pass through said slot defined by said flanges (9), whereas the head (16) is wider than said slot. 9. Concrete segments according to claim 8, wherein edges which are intended to form the end edges of the segments of adjacent annuli contain opposed sockets (21) and there being dowels (22) for insertion in the sockets of a said segment. 10. Concrete segments according to claim 9, wherein the dowels have radially-extending fins (24) of resiliently deformable material of greater width that the sockets (21). 11. Concrete segments according to claim 9 or 10, wherein the ends of the dowels are tapered. 12. Concrete segments according to claim 9, 10 or 11, wherein the dowels are of plastics material. 13. Concrete segments according to claim 9, 10, 11 or 12, wherein the sockets in which the dowels are to be inserted are unlined holes in the concrete of the segments. 14. Concrete segments according to any one of claims 9 to 13, wherein the sockets (21) are of substantially uniform cross-section.

Inventors: DOODY, JOHN PATRICK, SMITH, CHRISTOPHER RICHARD GRADWELL
Applicants: C.V. BUCHAN (CONCRETE) LIMITED
Application year: 1988
Main classification: E21D11
IPC codes: E04B1, E21D11