GB2139268A

GB2139268A - Arcuate concrete segments for tunnel or shaft linings

Info

Publication number: GB2139268A
Application number: GB08312296A
Authority: GB
Inventors: Samuel Bailey Hart Mitchell
Original assignee: Charcon Tunnels Ltd
Current assignee: Charcon Tunnels Ltd
Priority date: 1983-05-05
Filing date: 1983-05-05
Publication date: 1984-11-07
Also published as: GB8312296D0; GB2139268B

Abstract

The disclosure relates to an arcuate cast concrete tunnel lining segment (10) having connector bolts (33) extending through the segment at space locations around the segment parallel to its axis. Each connector bolt has a T-shaped head (34) at one end to project from one circumferential edge of the segment and engage in corresponding sockets (12) in a face or faces of adjacent segments, each socket having shoulders on either side thereof with which the head of the T-shaped bolt is engaged by turning the bolt in the socket to hold the bolt against withdrawal from the socket. In order to tension the connector bolt to secure the adjacent segments together, the other end of each bolt has a screw thread (35) which receives a nut (37) which is tightened on the bolt against the other end of the segment. The other end of the segment has corresponding sockets (12) to receive the T-shaped heads of connector bolts of further segments. <IMAGE>

Description

SPECIFICATION Improvements in or relating to arcuate concrete segments for tunnel or shaft linings This invention relates to arcuate concrete segments for tunnel or shaft linings.

The invention provides an arcuate concrete segment for a tunnel or shaft lining having spaced circumferentially extending edge faces, at least one connector member extending through the segment between said edge faces, one end of the member projecting from one edge of the segment and having a head at that end extending transversely of the member, the other end of the member being located in a recess in the other edge of the segment and having means to tension the member against the bottom of the recess, said other edge also having a socket cast therein of elongate transverse cross-section to receive the head of a connector member of an adjacent segment with the head aligned in the elongate direction of the socket and a cavity on at least one side of the socket spaced from the open end of the socket into which the head of the connector member may be turned, the cavity providing a shoulder facing away from the face of the segment against which the head on the connector member may be engaged to hold the connector member in the socket for attachment of two segments together.

The following is a description of one specific embodiment of the invention, reference being made to the accompanying drawings in which: Figure 1 is a perspective view of an assembly of arcuate concrete segments for a tunnel or shaft lining joined together edge to edge by T-bolts extending through the segments into sockets in the adjacent segments; Figure 2 is a perspective view of one of the sockets; Figure 3 is a side view of a socket; Figure 4 is an end view of the socket; Figure 5 is a plan view of the socket; Figures 6 and 7 are sectional views through two segments illustrated in the T-bolt/socket connections; and Figures 8 to 10 illustrate a further embodiment.

Referring firstly to Fig. 1 of the drawings, parts of two rings of arcuate pre-cast concrete segments 10 are shown with the segments of one ring "staggered or "half-lapped" with the segments of the adjacent ring.

Each segment has circumferentially extending edges 11 a, 11 b, and axially extending edges 5a and 5b. Each axially extending edge has two spaced apart semi-cylindrical grooves 6 extending from the inner surface of the segment towards the outer surface one of which is bridged by a pair of spaced semicircular hoops 7 and the other of which is bridged by a single semi-circular hoop 8. The ends of the hoops have legs extending into and cast in the concrete segment. The arrangement of the hoops is such that when two axial edges of adjacent segments are butted together, the single hoop projecting from the edges nest between the double hoops projecting from the opposing edges.

Collet type fastening devices 9 are inserted in the overlapping hoops and tapered pins 9a or the devices are driven into the collet to expand the devices and, by acting on the overlapping loops, clamp the axially extending faces of the adjacent segments firmly together. The construction of the joints formed by the overlapping hoops is described in greater detail in our U.K. Patent No.

2,004,931 and the construction of the expanding collet devices is described in greater detail in our U.K. Patent Application No.

8235006.

Two sockets indicated generally at 1 2 are cast into each segment adjacent the edge 11 a at positions disposed symmetrically around the face from the centre line of the segment, each socket having a rectangular open mouth 1 3 at the surface of the segment. The sockets will now be described in greater detail with reference to Figs. 2 to 5.

The socket 12 comprises a hollow elongate rectangular section plastics moulding having side walls 14 and end walls 14a. The socket has an open end 1 3 which, in situ, lies flush with the edge face 11 of the segment. The socket is intended to receive a T-shaped head of a connector bolt which will be described in greater detail later. The internal length and width of the socket are slightly greater than the corresponding length and width of the Tshaped head respectively so that the head can be slid into the socket with the T-shaped head extending lengthwise of the socket.

Partway along the socket from the mouth 1 3 the side walls 1 2 are stepped outwardly by arcuate shoulders 1 5 extending scross the sides 1 2 to form cavities 1 6 on either side of the sockets into which the ends of the Tshaped head on the connector bolt may be turned. The shoulders 1 5 within the socket form concavely curved seats 1 7 against which the ends of the T-shaped head can bear to retain the connector in the socket and two integral spring detents 18 are formed at spaced locations around each curved seat 1 8 to snap around and hold the ends of the Tshaped head against the seats 1 7.

The outer sides of the shoulders 1 5 are formed with grooves 1 9 and U-shaped reinforcing bars 20 are located on either side of the socket with the base of each bar located in the respective grooves 1 9 and the legs extending away from the socket. The end faces 1 5 of the socket are formed with Lshaped detents 21 adjacent the ends of the arcuate grooves 1 9 which are snapped over the reinforcing bars to hold them in place.

The free ends of the bars 20 may be turned outwardly as indicated at 22 to anchor into the concrete of the segment. The bars assist in taking the load imposed on the shoulder 1 5 by the head of the connector when a load is applied to the latter. The bottom of the socket 1 2 is closed by an end cap (not shown) to prevent the ingress of concrete into the socket during the casting of the segment.

Referring now to Figs. 6 and 7 of the drawings, the segment 10 is formed, adjacent each of the sockets 1 2 with a through-way 30 extending between the circumferential edge faces of the segments 11 a and 11 b. At the edge faces 11 a and 11 b the through-way opens into deep recesses 31, 32 respectively.

A connector member 33 extends with clearance along the through-way 30 and projects from the edge face 11 b of the segment. The projecting end of the member 33 is formed with a T-shaped head 34. The other end of the member 33 extends into the recess 31 at the edge 11 a of the segment and is screw threaded as indicated at 35 and a washer 36 and nut 37 are located on the threaded end of the segment with the washer in engagement with the bottom of the recess 31. The end of the member has a cross-slot to receive a tool for turning the member and also for determining the direction of the T-shaped head of the member during assembly.

Thus the circumferential edge 11 b of one segment in one ring engages the circumferential edges 11 a of two similar segments in the adjacent ring. Each connector member 33 of one segment is aligned with a socket 1 2 of the next segment and the T-shaped end of the connector member is passed into the socket 12 and turned in the cavity 1 6 by means of a tool engaged in the slot in the other end of the connector member 33 to engage the ends of the T-shaped head 34 against the seat 1 7 where they are held in place by the resilient detents 18. The nuts 37 on the connector members are then tightened to tension the members and clamp the segment 10 firmly to the adjacent segments.

It will be appreciated that many modifications may be made to the above described embodiment without departing from the scope of the invention. For example, the sockets 1 2 may be cast into the segment below the face 11 a with a straight or tapered opening formed in the face of the segment ieading into the open mouth 1 3 of each socket. Further, the sockets 1 2 may have cavities 1 6 on one side only thereof for engagement by an L-shaped headed connector element and Figs. 8 to 10 illustrate such an arrangement. The further sockets are generally similar to socket 1 2 described above and like parts have been allotted the same reference numerals.One end wall 14 of the socket is curved to receive the end of an L-shaped connector and the socket has only a single cavity 16 formed part way down one side wall 14 of the socket and providing a shoulder 1 5 in the wall of the socket to receive the end of the L-shaped connector element when the latter is turned in the cavity. A bridge 50 is formed integrally between the outer side of the shoulder 1 5 and the adjacent sides 14 of the socket to provide an aperture 51 to receive and hold a reinforcement member 52 cast in the concrete segment to assist in holding the socket in the segment. The open end 1 3 of the socket has an encircling rim 13a which, as indicated in Fig. 9, is cast in the surface 11 a of the segment 10. The connector rod 33 for use with the socket is provided with an L-shaped end 53 to engage in the socket in place of a T-shaped end as employed in the embodiment described above.

Claims

1. An arcuate concrete segment for a tunnel or shaft lining having spaced circumferentially extending edge faces, at least one connector member extending through the segment between said edge faces, one end of the member projecting from one edge of the segment and having a head at that end extending transversely of the member, the other end of the member being located in a recess in the other edge of the segment and having means to tension the member against the bottom of the recess, said other edge also having a socket cast therein of elongate transverse cross-section to receive the head of a connector member of an adjacent segment with the head aligned in the elongate direction of the socket and a cavity on at least one side of the socket spaced from the open end of the socket into which the head of the connector member may be turned, the cavity providing a shoulder facing away from the face of the segment against which the head on the connector member may be engaged to hold the connector member in the socket for attachment of two segments together.

2. An arcuate concrete segment as claimed in claim 1 wherein the connector member has a T-shaped head at said one end.

3. An arcuate concrete segment as claimed in claim 1 or claim 2 wherein the other end of the connector member is screwthreaded and a nut is located on the screwthreaded end to clamp the end against the bottom of the recess to tension the member when engaged in a socket of an adjacent segment to hold the two segments together.

4. An arcuate concrete segment as claimed in any of claims 1 to 3 wherein a through-way is provided in the segment in which the connector member extends with clearance to permit the member to be adjusted transversely in the through-way to line up with a socket in an adjacent segment.

5. A segment as claimed in any of the preceding claims whereintone, two or more such connector members are provided in the segment at locations spaced around the segment and a corresponding member of sockets are provided in said other edge of the segment to receive the connector member or members of an adjacent segment.

6. A segment as claimed in any of the preceding claims wherein the or each connector member has means at said other end for turning the member to line up the head of the member with the socket of an adjacent segment.

7. An arcuate concrete segment as claimed in claim 6 wherein the means for turning the member and also for indicating the alignment of the member comprise a slot in the end of the member to receive a tool for turning the member.

8. An arcuate concrete segment for a tunnel or shaft lining substantially as described with reference to and as illustrated in the accompanying drawing.