GB2474109A

GB2474109A - Tunnel and shaft linings

Info

Publication number: GB2474109A
Application number: GB201015983A
Authority: GB
Inventors: Colin Michael Eddie
Original assignee: MORGAN SINDALL
Current assignee: MORGAN SINDALL
Priority date: 2009-09-24
Filing date: 2010-09-23
Publication date: 2011-04-06
Anticipated expiration: 2030-09-23
Also published as: GB0916813D0; GB201015983D0; GB2474109B

Abstract

A method of forming a tunnel or shaft comprises creating a ground cavern and casting a plurality of arcuate prismatic concrete lining units 1 to 9 having the same constant radius, and at least one non-radial end face. The units are installed in the cavern to form a non-circular lining section of the shaft or tunnel. The invention also provides a method of forming the lining units and a set of lining units.

Description

TUNNEL AND SHAFT LININGS

[0001]This invention relates to a method of lining a tunnel or shaft, and a method of forming lining elements for tunnels and shafts.

[0002] It is an aim of the invention to provide a method capable of forming precast concrete units for ground support in both tunnels and shafts.

[0003] From a first aspect, the invention provides a method of forming a tunnel or shaft, comprising creating a ground cavern, forming a plurality of precast arcuate prismatic concrete lining units having the same constant radius, and at least one non-radial end face, and installing said units in the cavern to form a non-circular lining section of the shaft or tunnel. The units may differ in arc length and/or in the angle of an end face thereof.

[0004] The invention relies on the fact that units in the form of an arc of a circle can be assembled to form non-circular figures having centres that do not coincide with the centre of the arc, such as figures that appear generally "square" or "rectangular". Thus the lining section can have a width that is equal in two perpendicular directions, or a length greater than its width, for example in a ratio of between 1:1 and 4:1.

[0005] A series of the lining sections can be installed in sequence to form an elongate lining of a caisson, shaft or tunnel.

[0006]From a second aspect, the present invention provides a method of forming a lining unit for a tunnel or shaft, comprising: -providing a generally arcuate mould of constant cross section having a convex surface of constant radius, and two ends, at least one of the ends being non-radial, and -casting a lining unit of corresponding shape.

[0007]Prior to casting, the inclination and/or circumferential position of at least one of the ends may be adjusted. For this purpose the at least one adjustable end may be provided by a movable and/or interchangeable shutter.

[0008] From a third aspect, the invention provides a set of arcuate tunnel or shaft lining units, each having the same radius, at least some of the lining units each having at least one non-radial end face. The units may differ in arc length and/or in the angle of an end face thereof.

[0009] The lining units formed in the invention may comprise concrete.

[0010] Embodiments of the invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which: [0011] Figures 1A to 1G and 1J schematically show the moulding of eight different lining units according to the invention; [0012] Figure 1H shows the moulding of a lining unit which can be used with the invention; [0013] Figures 2A to 2E are schematic horizontal sections of shaft linings formed from the lining units of Figures 1A to 1J; [0014] Figures 3 to 5 are schematic vertical sections showing methods of lining shafts with the units of the invention; and [0015]Figure 6 is a schematic vertical section of a tunnel lined according to the invention.

[0016] Figures 1A to 1J schematically show the moulding of arcuate concrete liners 1 to 9 respectively. The mould has a base 10 with an upper convex surface formed as an arc of a circle. Each mould has two end formers which are attached to the base 10. In this example there are four different types of formers 11 to 14 respectively. Formers 11 are radial with respect to the bases 10, i.e. an imaginary extension of formers 11 would intersect the centre of the circle including the arc of the respective base. Formers 12 are offset by a small angle with respect to a radius of that circle and formers 13 and 14 are offset by increasingly larger angles.

[0017] The mould of Figure 1A has a former 13 at its left hand end and a radial former 11 at its right hand end. The mould of Figure lB is a mirror image of the mould of Figure 1A. The mould of Figure 1C has formers 14 at both ends. The mould of Figure 1D has a former 14 at its left hand end and a radial former 11 at its right hand end and the mould of Figure 1E is a mirror image of Figure 1D. The mould of Figure iF has formers 14 at both ends. The mould of Figure 1G has a former 12 at its left hand end and a radial former 11 at its right hand end. The mould of Figure 1H has radial formers 11 at both ends and is for forming a lining unit 8 not according to the invention but for use with units according to the invention. The mould of Figure 1J is a mirror image of the mould of Figure 1G.

[0018]The base 10 is used in each of the different moulds, which are assembled by interchanging the formers 11 to 14 as required to provide lining units with correctly angled end faces. In addition, the formers can be placed at different positions along the surface of the base 10 to provide units of different lengths.

[0019] Referring to Figure 1A for example, with the two end formers 11, 13 in place on the base 10, concrete is poured into the mould. The convex surface of the base 10 provides a corresponding concave surface of the lining unit 1.

End former 11 provides a radial end face at one end of the unit and end former 13 provides a non-radial end face at the other end. The convex surface of the lining unit can be formed by hand for example. The exact shape of this convex surface is not so important as, in the shaft or tunnel, it will be installed against an irregular cavern surface.

[0020] Figures 2A to 2E show shaft linings formed from the units 1 to 9.

Figure 2A shows a lining formed from four units 1 and four units 2. Figure 2B shows a lining formed from two units 1, two units 2 and two units 3. Figure 2C shows a lining formed from two units 3, two units 7, two units 8 and two units 9. Figure 2D shows a lining formed from two units 3, two units 4 and two units 5. Figure 2E shows a lining formed from two units 4, two units 5 and two units 6.

[0021] It will be appreciated that whilst each of the units 1 to 9 taken alone is shaped as an arc of a circle, when assembled, the units will line shafts or tunnels of approximately square or oblong cross-section as shown. This is more efficient than a circular cross-section when considering the installations of a shaft or tunnel for personal or vehicular access.

[0022] The lining units of each set have the same radius, but are not centred on the same point.

[0023] Figures 3 to 6 shows examples of the use of units of the invention.

Figure 3 shows a caisson shaft sinking method in which sets of units 1 are successively sunk into a cavern through a guide collar 20, the set which is to be lowermost being sunk first.

[0024]Figure 4 shows an underpinning method of lining a shaft in which successive sets of lining units are installed into a cavern starting at the top.

[0025] Figure 5 shows a "bottom up" method in which a base slab 21 is placed at the bottom of a cavern and sets of lining units are built up therefrom.

[0026] Figure 6 shows an underground tunnel lined according to the invention.

[0027] The lining units can have holes formed therein and can be installed in the caverns and simultaneously attached together using sockets, dowels, studs and bolts known in the art.

Claims

CLAIMS1. A method of forming a tunnel or shaft, comprising creating a ground cavern, forming a plurality of precast arcuate prismatic concrete lining units having the same constant radius, and at least one non-radial end face, and installing said units in the cavern to form a non-circular lining section of the shaft or tunnel.
2. A method according to claim 1, wherein the units differ in arc length.
3. A method according to claim 1 or 2, wherein the units differ in the angle between an end face thereof and said radius.
4. A method according to claim 1, 2 or 3, wherein the lining section has a width that is equal in two perpendicular directions.
5. A method according to claim 1, 2 or 3, wherein the lining section has a length that is greater than its width, for example in a ratio of between 1:1 and 4:1.
6. A method according to any preceding claim, wherein a series of the lining sections is installed in sequence to form an elongate lining of a caisson, shaft or tunnel.
7. A method of forming a lining unit for a tunnel or shaft, comprising: * providing a generally arcuate mould of constant cross section having a convex surface of constant radius, and two ends, at least one of the ends being non-radial, and * casting a lining unit of corresponding shape.
8. A method according to claim 7, wherein the inclination of at least one of the ends is adjusted.
9. A method according to claim 7 or 8, wherein the circumferential position of at least one of the ends is adjusted.
10. A method according to claim 8 or 9, wherein the at least one adjustable end is provided by a movable and/or interchangeable shutter.
11. A set of arcuate tunnel or shaft lining units, each having the same radius, at least some of the lining units each having at least one non-radial end face.
12. A set of lining units according to claim 11, wherein the units differ in arc length.
13. A set of lining units according to claim 11 or 12, wherein the units differ in the angle between an end face thereof and the radius of the units.