GB2046815A - Tunnel lining units - Google Patents

Abstract

A unit for lining and supporting the roof of a tunnel comprises an arch crown (10), and a roof lining covering (12) which extends from the arch crown (10) to a free end. The covering (12) is held in this cantilevered manner by means of straps (14) engaging the free end of the covering (12) and the arch spy crown (10). The unit may also comprise a second arch crown (11), held to the first by tie rods (15), with the gap between the arch crowns filled by a second roof lining covering (12). <IMAGE>

Description

SPECIFICATION Tunnel lining units Tunnels, and more particularly roadways in coal mines, are, after they have been bored, frequently supported by arched girders often of "H" cross-section. The shape of such arch crowns, as they are known, is generally semicircular and they are supported on legs. The arch crowns are formed separately from the legs, for ease of transport and erection, and, when in position, are connected to the legs by fish plates. The legs are usually stood on substantial floor pads to spread the load carried by the arch crown to the floor. The load of the tunnel roof is transmitted to the arch crown by rough packing between the arches and the roof. Since the tunnel will tend to converge after boring, the contact between the tunnel and the arch will tend to increase with time.

In horizontal tunnels, the arch crowns lie in vertical planes. In inclined tunnels, the arch crowns are set in planes which are a compromise between vertical planes and planes which are normal to the length of the tunnel.

In order to prevent the arch crowns falling, to resist horizontal components of forces from the strata and to maintain a constant pitch between arch crowns, the arch crowns are connected together by ties and/or struts. In addition, to protect personnel from falling debris and to spread the support effect over as large an area as possible, it is frequently necessary to cover the tunnel between adjacent arch crowns. Previous proposals for such covering have included corrugated iron sheeting extending over the tops of the arches, wood over the tops of the arches or between the flanges of the H-section arch crowns or reinforced concrete slabs set between the flanges. Such coverings are positioned after positioning of the arch crowns in their final positions in a tunnel.

The provision of coverings of the previously proposed kinds is both time consuming and potentially dangerous. While such coverings are being provided, the tunnel boring must stop. It is an object of the invention to provide a covering for tunnels which mitigates these disadvantages.

According to a first aspect of the present in ention, there is provided a unit for supporting and lining the roof of a tunnel, the unit comprising a roof support portion for transversely spanning the roof or a part of the roof of the tunnel, a roof lining portion extending from one end abutting the support portion to a free end, and means to hold the roof lining portion in a cantilevered manner such that its weight is transmitted to the support portion.

Preferably the roof support portion comprises an arcuate girder, advantageously of Hcross-section having flanges joined by a web.

The means to hold the roof lining portion may comprise one or more straps engaging the arcuate girder, and preferably engaging the roof lining portion at the free end.

The unit may further comprise an additional roof support portion and an additional roof lining portion, one end of which fixedly abuts the roof support portion and the other end of which fixedly abuts the additional roof support portion.

According to a second aspect of the invention, there is provided a method of supporting and lining the roof of a tunnel comprising the steps of lifting into position a unit as described in the first aspect of the invention, attaching the unit to a previously erected unit with the cantilevered roof lining portion of one of the units abutting a respective roof support portion of the other of the units, connecting the or each roof support portion of the newly added unit to legs, and repeating the above steps with a further unit.

Preferably grout is introduced between the unit and the tunnel roof.

An embodiment of the invention will now be more particularly described by way of example and with reference to the accompanying drawings, wherein: Figure 1 is a perspective view to illustrate the mode of construction of a tunnel lining using units according to the invention; Figure 2 is a perspective view of a unit according to the invention; Figure 3 is an end elevation of the unit shown in Fig. 2; Figure 4 is a section taken along the line IV-IV of Fig. 3; and Figure 5 is a section taken along the line V-V of Fig. 3.

Referring now to the drawings, the unit comprises two arcuate girders or arch crowns 10, 11 of H-section. The first arch crown 10 is connected to the second arch crown 11 by struts 1 5 and a tunnel lining covering 1 2 extends between the opposing faces of the webs of the two arch crowns 10, 11. The covering comprises a plurality of connected corrugated metal panels, with the corrugations extending normal to the end edges of the panels and in contact with the flanges of the arch crowns. One side edge of each panel is provided with a side lip 1 3 which forms a location for a side edge of an adjoining panel to connect together the adjacent panels and thus to form a continuous covering.

The panels extending from the other side of the web of the first arch crown 10 are held thereto in a cantilevered manner by means of straps 1 4 which hook over the free end edges of the panels and also hook over the upper flange of the first arch crown 1 0. Thus the panels are held so that they extend normal or substantially normal to the plane of the first arch crown 10.

This unit may be assembled at a location away from the final desired location of the unit in a tunnel. The unit is then moved into position for example by use of the arch crown lifting machine described in our co-pending British patent application No. 15080/77. The free end of the cantilevered roof lining covering 1 2 is then engaged with the flanges of the next adjacent arch crown and the two arch crowns connected by struts 1 5. The arch crowns of the unit are also connected to legs 1 6 by fish pates 1 7. Further units are then assembled and moved into position to line the tunnel as the tunnel is bored. A quick setting grout such as a gypsum based grout or an anhydrite based grout is then injected between the lining and the tunnel to establish contact between the tunnel and the lining.

Obviously, it would also be possible to assemble the units by engaging an end arch crown of a unit with the cantilevered roof lining covering 1 2 of a previously erected unit.

It will be appreciated that the unit may comprise just a single arch crown and cantilevered covering or three or more arch crowns may be included in a unit with a respective number of coverings extending between. The arch crowns may be of any desired shape or cross-section, and the corrugations may be of any convenient shape. The ends of the panels may be so shaped and dimensioned as to assist their insertion between the flanges of an H-section arch crown.

Claims (14)

1. A unit for supporting and lining the roof of a tunnel, the unit comprising a roof support portion for transversely spanning the roof or a part of the roof of the tunnel, a roof lining portion extending from one end abutting the support portion to a free end, and means to hold the roof lining portion in a cantilevered manner such that its weight is transmitted to the support portion.

2. A unit as claimed in claim 1, wherein the roof support portion comprises an arcuate girder.

3. A unit as claimed in claim 2, wherein the arcuate girder is of H-cross-section having flanges joined by a web.

4. A unit as claimed in claim 3 wherein the roof lining portion abuts the arcuate girder and engages between the flanges of the Hsection.

5. A unit as claimed in any one of claims 2 to 4, wherein the roof lining portion is substantially normal to the general plane of the arcuate girder.

6. A unit as claimed in any one of claims 2 to 5, wherein the means to hold the roof lining portion comprises one or more straps engaging the arcuate girder.

7. A unit as claimed in claim 6, wherein the or each strap engages the roof lining portion at the free end.

8. A unit as claimed in any one of claims 2 to 7, wherein the roof lining portion has corrugations extending substantially normally to the general plane of the arcuate girder.

9. A unit as claimed in claim 8, wherein the roof lining portion comprises a plurality of corrugated panels connected one to another by a side lip on one panel engaging a side lip of an adjoining panel

10. A unit as claimed in any one of the preceding claims, further comprising an additional roof support portion and an additional roof lining portion, one end of which fixedly abuts the roof support portion and the other end of which fixedly abuts the additional roof support portion.

11. A unit as claimed in claim 10, wherein the roof support portion and the additional roof support portion are held together by one or more ties.

12. A unit for supporting and lining the roof of a tunnel substantially as hereinbefore described with reference to the accompanying drawings.

1 3. A method of supporting and lining the roof of a tunnel comprising the steps of lifting into position a unit as claimed in any one of the preceding claims, attaching the unit to a previously erected unit with the cantilevered roof lining portion of one of the units abutting a respective roof support portion of the other of the units, connecting the or each roof support portion of the newly added unit to legs, and repeating the above steps with a further unit.

14. A method as claimed in claim 13, comprising the additional step of introducing grout between the unit and the tunnel roof.

1 5. A method of supporting and lining the roof of a tunnel substantially as hereinbefore described with reference to the accompanying drawings.