GB2026064A - Tunnel linings - Google Patents

Abstract

An arcuate tunnel unit comprises an arcuate cast concrete block (13 or 14) having a projection on one end face and a recess in the other end face. An arcuate tunnel lining segment (10) is built from three units (13, 14, 13) arranged end-to-end with adjacent projections and recesses inter-engaging. The units (13, 14, 13) are held together during handling and erection in a tunnel by a pair of tie rods (16) passing through channels in the blocks and engaging nuts (17) in pockets (15). An annular ring is built from a number of segments (10), adjacent segments being held together by tie-rods (18) and specially adapted blocks (not shown) being used at two opposed locations in the rings. The depth of each recess is less than that of each projection to permit limited relative tilting of the block and the gaps between adjacent end faces of the blocks on either side of the projections and recesses may be filled with compressible filler material. <IMAGE>

Description

SPECIFICATION Arcuate tunnel lining units This invention relates to arcuate tunnel lining units and to arcuate tunnel lining segments and annular rings made up of such units.

The invention provides an arcuate tunnel lining unit comprising a cast concrete block having, on one circumferential end face, a convex projection extending at least partway along the face parallel to the axis of the arcuate block between the inner and outer edges of the block and a concave recess extending along the other end face parallel to said axis of the block between the inner and outer edges of the block, the depth of the recess being less than that of the projection so that, when one such block is assembled end to end with another block with the projection on said one end face engaging in the recess in the end face of the other block the end faces of the blocks on either side of the projection and recess can be spaced apart, permitting tilting of the blocks with respect to each other in one direction limited by engagement of the inner edges of the blocks and in the opposite direction limited by engagement of the outer edges of the blocks.

The invention also provides an arcuate tunnel lining unit comprising a cast concrete block having, on one circumferential end face, a convex projection extending at least partway along the face parallel to the axis of the arcuate block between the inner and outer edges of the block and a concave recess extending along the other end face parallel to said axis of the block between the inner and outer edges of the block, the depth of the recess being less than that of the projection so that, when one such block is assembled end to end with another block with the projection on said one end face engaging in the recess in the end face of the other block, the end faces of the blocks on either side of the projection and recess are spaced apart to receive a compressible filler material which permits limited tilting of the blocks with respect to each other.

Preferably the concave projection on said one end face of the block is a part cylindrical projection extending along the length of said end face of the block and the recess in the other end face of the block is a part cylindrical recess extending along the full length of the end face.

Preferably the projection is located mid-way between the inner and outer edges of the block and the recess is correspondingly located midway between the inner and outer edges of the block.

The invention also provides an arcuate tunnel lining segment comprising a plurality of units according to any of the arrangements referred to above, tie means holding the plurality of blocks together end-to-end in arcuate formation, the projection on said one end face of one of the or each adjacent pair of blocks engaging in the recess in said other end face of the other of that pair of blocks.

A compressible filler material may be disposed between the adjacent end faces on either side of the inter-engaging projections and recesses.

The compressible filter material may comprise a rubber based filler material or may comprise a bitumen material such as "Sealastrip".

The tie means holding the blocks together may comprise at least one curved tie bar extending through the arcuate blocks and having means at both ends thereof to clamp the blocks together.

More specifically, the end blocks of each segment may have recesses on the inner surfaces adjacent the ends of the segment and the tie bar may extend through the blocks of the segment from recess to recess and nuts may be screwed on to the ends of the tie bar projecting into the recesses to clamp the blocks together.

In one arrangement, two such tie bars are spaced apart in the segment parallel to the segment axis and extending between pairs of recesses located adjacent the ends of the segment.

Bores may extend between the recesses and the ends of the segment to receive further tie bars for securing adjacent segments together.

In an alternative arrangement of the tie bar each end block of each segment has a recess on the outwardly facing circumferential end face thereof, the tie bar extending from recess to recess and nuts being screwed on to the ends of the tie bar projecting into the recesses to clamp the blocks together.

Two such tie bars may be spaced apart in the segment parallel to the segment axis and extending between pairs of recesses located at the ends of the segment.

Preferably, a clearance is provided between the tie bar or tie bars and the blocks, the clearance increasing towards the end faces of the blocks.

A compressible material such as the rubber based filler material or bitumen material referred to above may be provided on at least one end face of the segment on either side of the projection or the recess on said end face.

The invention further provides an annular ring of such segments joined end-to-end in a ring with a key block at one location around the ring.

The invention also provides a complete annular ring of such segments with a segment at one location around the ring having a projection at both ends and a key block at the diametrically opposite location also having projections on both side faces to engage in corresponding recesses in the ends of the adjacent segments.

The following is a description of a specific embodiment of the invention, reference being made to the accompanying drawings in which: Figure 1 is an end view of a ring of arcuate tunnel segments in accordance with the invention; Figure 2 is a section on the line A-A of Fig.

1; Figure 3 is a section on the line B-B of Fig.

1; Figure 4 is a section on the line C-C of Fig.

1; Figure 5 is a view looking in the direction of the arrow E on Fig. 1; Figure 6 is a section on the line F-F of Fig.

5; Figures 7 to 9 are detailed views of a joint between adjacent blocks of each arcuate segment and Figure 10 shows one possible deflection of a complete ring of the segments.

Referring firstly to Fig. 1 of the drawings, there is shown a ring of arcuate tunnel lining segments each of which is indicated generally by the reference numeral 10. Each segment 10 subtends an angle of 51 at the common axis 11 of the tunnel and the ring is completed by a small key 1 2 at the top of the ring.

Each segment 10 is made up of three arcuate concrete blocks located end-to-end around the common axis 11 and comprising end blocks 1 3 and a central block 14.

As can be best seen in Figs. 5 and 6 of the drawings, each end block 1 3 of each segment 10 has two deep pockets 1 5 cast into the inner surface of the block adjacent the end of the segment. Arcuate steel tie bars 1 6 extend through cast-in bores in the blocks 13, 14 between the pockets 1 5 and nuts 1 7 screwed on to the ends of the tie bars which project into the pockets to clamp the blocks 13, 14 together. The adjacent segments 10 are secured together by further short tie bars 18 which extend through cast in-bores extending from the pockets 1 5 to the segment ends.

Reference is now made to Figs. 7 to 9 of the drawings which iliustrate in detail the form of joint between adjacent blocks of the segments 1 0. This form of joint is provided both between blocks 1 3 and 14 of one segment and between the adjacent blocks 1 3 and 14 of one segment and between the adjacent blocks 1 3 of adjacent segments. The adjacent end faces 19, 20 of each pair of bocks are formed, respectively with a part cylindrical recess 21 located centrally of the end face of the block and extending along the end face parallel to axis 11 and a part cylindrical projection 22 on the other end face again located centrally of the end face and extending parallel to the axis 11 along the end face.

The projection 22 fits partially into the recess 21 so that the end faces of the blocks on either side of the projection are spaced apart and the blocks can therefore tilt by a limited amount with respect to each other about an axis parallel to the axis 11. The range of tilting movement provided in the particular example shown in the drawings is 15 .

The gaps between the end faces 1 9 and 20 on either side of the projection 22 are filled with a compressible material such as a bitumastic material, for example, "Sealastrip" or a rubber based material to provide a seal between adjacent blocks. Fig. 8 of the drawings shows the pair of blocks tilted to one limit of the movement provided and Fig. 9 shows the pair of blocks tilted to the other limit of movement.

Referring to Fig. 1 of the drawings, the lower-most segment 1 Oa in the ring of segments is constructed to have projections 22 at both ends thereof. Further segments are built up symmetrically around the ring and the upper-most segments have recesses 21 at their upper ends which engage the key segment 1 2. The latter has cylindrical projections 24 on both sides thereof to engage in the recesses 21 in a similar manner to the projections 22 and compressible material is provided on either side of the projections 24.

Fig. 10 of the drawings shows one possible deflection of an originally cylindrical tunnel lining made up of the segments according to the invention when subjected to stresses which cause the blocks to tilt with respect to one another. The tie rods are of relatively light weight construction since they are only intended to hold the blocks of the segments together during handling prior to erection and during erection and they bend readily at the joints between adjacent blocks when subjected to stress.

Referring to Fig. 6, a clearance is provided between the tie bars 16, 1 8 and the cast-on bores. The clearance is increased towards the ends of each block to permit the limited tilting of the blocks relative to each other.

In some cases the provision of pockets 1 5 in the inner surfaces of the blocks 1 3 may weaken the blocks more than is permissible.

Instead of providing the pockets in the inner surfaces, recesses may be provided in the outwardly facing ends of the blocks 13, between which cast-in bores extend. With this arrangement adjacent segments 10 may be joined together with a joint of the type described in our U.K. Patent Specification No.

(31169/78).

In cases where the provision of compressible material between adjacent end faces is not necessary, it is advantageous to provide a material, such as soft woods, between adjacent portions of the end faces to either side of the recess and projection which prevents tilting of the blocks relative to one another during handling and erection, but which col lapses under more severe loading to permit tilting of the blocks. In this case a bitumastic material may be provided on the projections or recesses to act as a lubricant during tilting.

Whereas the lower-most segment 1 Oa in Fig. 1 has projections on both end faces, a ring of segments may be built up without the use of such a segment. In this case a key block would be used having a projection on one end face and a recess on the other end face.

Claims (21)

1. An arcuate tunnel lining unit comprising a cast concrete block having, on one circumferential end face, a convex projection extending at least partway along the face parallel to the axis of the arcuate block between the inner and outer edges of the block and a concave recess extending along the other end face parallel to said axis of the block between the inner and outer edges of the block, the depth of the recess being less than that of the projection so that, when one such block is assembled end to end with another block with the projection on said one end face engaging in the recess in the end face of the other block, the end faces of the blocks on either side of the projection and recess can be spaced apart, permitting tilting of the blocks with respect to each other in one direction limited by engagement of the inner edges of the blocks and in the opposite direction limited by engagement of the outer edges of the blocks.

2. An arcuate tunnel lining unit comprising a cast concrete block having, on one circumferential end face, a convex projection extending at least partway along the face parallel to the axis of the arcuate block between the inner and outer edges of the block and a concave recess extending along the other end face parallel to said axis of the block between the inner and outer edges of the block, the depth of the recess being less than that of the projection so that, when one such block is assembled end to end with another block with the projection on said one end face engaging in the recess in the end face of the other block, the end faces of the blocks on either side of the projection and recess are spaced apart to receive a compressible filler material which permits limited tilting of the blocks with respect to each other.

3. A unit as claimed in claim 1 or claim 2, wherein the concave projection on said one end face of the block is a part cylindrical projection extending along the length of said end face of the block and the recess in the other end face of the block is a part cylindrical recess extending along the full length of the end face.

4. A unit as claimed in any preceding claim, wherein the projection is located midway between the inner and outer edges of the block and the recess is correspondingly located midway between the inner and outer edges of the block.

5. An arcuate tunnel lining segment comprising a plurality of units as claimed in any preceding claim, the means holding the plurality of blocks together end-to-end in arcuate formation, the projection on said one end face of one of the each adjacent pair of blocks engaging in the recess in said other end face of the other of that pair of blocks.

6. A segment as claimed in claim 5, further comprising a compressible filler material disposed between the adjacent.end faces on either side of the inter-engaging projections and recesses.

7. A segment as claimed in claim 6, wherein the compressible filler material comprises a rubber based filler material or a bitumen material such as "Sealastrip".

8. A segment as claimed in any one of claims 5 to 7, wherein the tie means holding the blocks together comprises at least one curved tie bar extending through the arcuate blocks and having means at both ends thereof to clamp the blocks together.

9. A segment as claimed in claim 8, wherein the end blocks of each segment have recesses on the inner surfaces adjacent the ends of the segment, the tie bar extending through the blocks of the segment from recess to recess and nuts being screwed on to the ends of the tie bar projecting into the recesses to clamp the blocks together.

10. A segment as claimed in claim 9, wherein two such tie bars are spaced apart in the segment parallel to the segment axis and extend between pairs of recesses located adjacent the ends of the segment.

11. A segment as claimed in claim 10, wherein bores extend between the recesses and the ends of the segment to receive further tie bars for securing adjacent segments together.

1 2. A segment as claimed in claim 8, wherein each end block of each segment has a recess on the outwardly facing circumferential end face thereof, the tie bar extending from recess to recess and nuts being screwed on to the ends of the tie bar projecting into the recesses to clamp the blocks together.

1 3. A segment as claimed in claim 12, wherein two such tie bars are spaced apart in the segment parallel to the segment axis and extend between pairs of recesses located at the ends of the segment.

14. A segment as claimed in any one of claims 8 to 13, wherein a clearance is provided between the tie bar or tie bars and the blocks, the clearance increasing towards the end faces of the blocks.

1 5. A segment as claimed in any one of claims 5 to 14, wherein a compressible material is provided on at least one end face of the segment on either side of the projection or the recess on said end face.

1 6. A segment as claimed in claim 15, wherein the compressible material comprises a rubber based filler material or a bitumen material.

1 7. An annular ring of segments comprising a plurality of segments as claimed in any one of claims 5 to 1 6 joined end-to-end in a ring with a key block at one location around the ring.

1 8. An annular ring of segments comprising a plurality of segments as claimed in any one of claims 5 to 16, a segment at one location around the ring having a projection at both ends and a key block at the diametrically opposite location also having projections on both side faces to engage in corresponding recesses in the ends of the adjacent segments.

1 9. An arcuate tunnel lining unit substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

20. An arcuate tunnel lining segment substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

21. An annular ring of segments substantially as herein described with reference to and as illustrated in the accompanying drawings.