WO2005075792A1

WO2005075792A1 - Apparatus for supporting injected wet concrete during the formation of a concrete tunnel

Info

Publication number: WO2005075792A1
Application number: PCT/GB2005/000353
Authority: WO
Inventors: Andrew Michael Finean
Original assignee: Andrew Michael Finean
Priority date: 2004-02-04
Filing date: 2005-02-02
Publication date: 2005-08-18
Also published as: EP1711683A1; GB0402484D0

Abstract

Apparatus (2) for supporting injected wet concrete (4) during the formation of a concrete tunnel (6), the apparatus (2) comprising a tube (8) and a plurality of ring members (10) positioned inside the tube (8), and the apparatus (2) being such that in use the wet concrete (4) is injected around the outside of the tube (8) and is supported by the tube (8) until the wet concrete (4) dries and becomes self-supporting, the ring members (10) prevent the tube (8) collapsing inwardly due to external pressure, the tube (8) is formed by a plurality of elongate members (12) which extend longitudinally and which are arranged side by side in a circle, the ring members (10) extend transversely across the tube (8), and the elongate members (12) are flexible and movable relative to one another thereby enabling the tube (8) to bend and allow the concrete tunnel (6) to be formed with curves.

Description

APPARATUS FOR SUPPORTING INJECTED WET CONCRETE DURING THE FORMATION OF A CONCRETE TUNNEL

This invention relates to apparatus for supporting injected wet concrete during the formation of a concrete tunnel. Tunnelling machines are known comprising a cutting head, drive means for driving the cutting head, and a cylindrical tunnelling shield. The tunnelling machines are used in soft ground, with the cutting head cutting into the soft ground, and the tunnelling shield supporting the ground between the excavation and subsequent tunnel building operations. The tunnel building operations include the need to erect a lining in the tunnel. Tunnel linings were originally formed using brickwork on an erected former, and the tunnel linings were then back grouted in order to fill voids behind the erected brickwork. Today, large concrete or iron segments have taken the place of the bricks. The general method of erection and the requirement for the back grouting however remains much the same. Generally, the method of erection and the requirement for the back grouting causes the formation of tunnel linings to be slow and therefore expensive in terms of man-power and the pre-casting of tunnel segments. It is an aim of the present invention to reduce the above mentioned problem. Accordingly, in one non-limiting embodiment of the present invention there is provided apparatus for supporting injected wet concrete during the formation of a concrete tunnel, the apparatus comprising a tube and a plurality of ring members positioned inside the tube, and the apparatus being such that in use the wet concrete is injected around the outside of the tube and is supported by the tube until the wet concrete dries and becomes self-supporting, the ring members prevent the tube collapsing inwardly due to external pressure, the tube is formed by a plurality of elongate members which extend longitudinally and which are arranged side by side in a circle, the ring members extend transversely across the tube, and the elongate members are flexible and movable relative to one another thereby enabling the tube to bend and allow the concrete tunnel to be formed with curves. The apparatus of the present invention may be constructed from inexpensive materials. It avoids the need to utilise the concrete or iron segments, and it also avoids the need for the back grouting. The apparatus may be one in which the elongate members are rods. The elongate members, for example the rods, may be solid or hollow. Preferably, the elongate members are circular in cross section. Other cross sectional shapes may be employed so that, for example, the elongate members may be square, hexagonal or octagonal in cross section. Generally, the elongate members may be of a variety of cross sectional shapes providing they are able to be assembled in the form of a tube. The elongate members may be formed in one piece. Alternatively, the elongate members may be formed in at least two sections which are connected together by connector means. These sections may be connected together by screw connector means. Other types of connector means may be employed including quick release connector means such for example as a bayonet connector means. The elongate members may be made in a wide variety of flexible supportive material including, for example, steel, carbon fibre, wood and fibreglass. Preferably, the ring members are circular in cross section. Also preferably, the ring members are solid. Generally, the ring members may be solid or hollow, and they may be of a wide variety of cross sectional shapes. The ring members are preferably made of steel. Other materials may be employed that are able to provide the required strength for the ring members. The apparatus may include attachment means for attaching one end of the tube to a tunnel boring machine. The attachment means may be a retaining ring. The elongate members may be screwed into, bolted through, or otherwise connected to the retaining ring. The elongate members may then abut each other along their lengths. Usually, the elongate members will only be attached to the attachment means, and not each other. This enables the elongate members to move freely against each other along their lengths. It could however be advantageous loosely to connect the ring members together to prevent collapse if for any reason the concrete pressure was not transmitted to the ring members via the elongate members. The apparatus may include liner means positioned around the outer surface of the tube. The liner means can then contact the concrete of the concrete tunnel as the concrete tunnel is being formed. The liner means may act to prevent the elongate members from scouring against the concrete as the elongate members slide through the formed concrete tunnel. The liner means may also act to reduce friction, and to even out transmitted concrete pressure. The liner means may be a plurality of flexible bands. The present invention also extends to a tunnel boring machine when provided with the apparatus of the invention. The tunnel boring machine may operate in various ways for cutting the ground. The most usual way is with a rotary cutting head but alternative ways include the use of "hand digging" devices, back hoes, and road headers. The tunnel boring machine preferably comprises a cutting head, drive means for driving the cutting head, a cylindrical tunnelling shield, first conduit means for removing spoil from the cutting head, second conduit means for providing the wet concrete, and push/pull means for pushing the cutting head fowardly for cutting purposes and for pulling the tube up to the cutting head for wet concrete support purposes. The cutting head will usually be a circular cutting head but other types of cutting head may be employed. In the case of tunnel boring machines using the hand digging devices or the road headers, then the tunnelling shield may be circular, arched or square in shape. The tunnel boring machine may be such that other types of spoil removal means may also be employed. The apparatus may include mixer means for mixing water and dry cement to form the wet cement, and pump means for pumping the wet cement to the second conduit means. The second conduit means may include a plurality of outlets arranged in a circle. The drive means will usually be a hydraulic drive motor. The drive means may alternatively be an electric drive motor, or a diesel or petrol driven motor. An embodiment of the invention will now be described solely by way of example and with reference to the accompanying drawings in which: Figure 1 is a longitudinal section through apparatus for supporting injected wet concrete during the formation of a concrete tunnel, the apparatus being shown in use and attached to a tunnel boring machine; Figure 2 is a perspective view, partially cut away, of the apparatus shown in Figure 1; Figure 3 is a section on the line A-A shown in Figure 1 ; and Figure 4 is a section on the line B-B shown in Figure 1. Referring to the drawings, there is shown apparatus 2 for supporting injected wet concrete 4 during the formation of a concrete tunnel 6. The apparatus 2 comprises a tube 8 and a plurality of ring members 10 positioned inside the tube 8. The apparatus 2 is such that, in use, the wet concrete 4 is injected around the outside of the tube 8. The wet concrete 4 is supported by the tube 8 until the wet concrete 4 dries and becomes self-supporting. The ring members 10 prevent the tube 8 from collapsing inwardly due to external pressure. The tube 8 is formed by a plurality of elongate members 12 which are best shown in Figures 2 and 3. The elongate members 12 extend longitudinally along the tube 8. The elongate members 12 are arranged side by side in a circle, thereby forming the tube 8. As best shown in Figure 2, the ring members 10 extend transversely across the tube 8. The elongate members 12 are flexible and they are movable relative to one another, thereby enabling the tube 8 to bend and allow the concrete tunnel 6 to be formed with curves. As shown in Figures 2 and 3, the elongate members 12 are solid rods which are circular in cross section. The elongate members 12 are each formed in one single piece. As best seen from Figures 1 and 2, the ring members 10 are solid, and circular in cross section. The apparatus 2 includes attachment means in the form of a retaining ring 14 for attaching one end 16 of the tube 8 to a tunnel boring machine 18. The ends of all of the elongate members 12 that constitute the end 16 of the tube 8 are attached to the retaining ring 14. The attachment may be achieved by having the elongate members 18 screwed into or bolted through the retaining ring 14. The elongate members 12 then trail from the retaining ring 14 in a squid-like manner, gaining the illustrated circular form by virtue of concrete pressure pushing the elongate members in tight formation onto the ring members 10. The apparatus 2 may include liner means 13 positioned around the outer surface of the tube 8. The liner means 13 is in the form of a plurality of flexible bands. The tunnel boring machine 18 comprises a cutting head 20, drive means 22 for driving the cutting head 20, and a cylindrical tunnelling shield 24. The tunnel boring machine 18 also includes first conduit means 26 for removing spoil from the cutting head 20. The spoil will be cut ground 28 which is cut by the cutting head 20. The tunnelling machine 18 also includes second conduit means 30 which is best shown in Figure 3. The second conduit means 30 is for providing the wet concrete. Also provided is push/pull means 32 for pushing the cutting head 20 forwardly for cutting purposes, and for pulling the tube 8 up to the cutting head 20 for wet concrete support purposes. The push/pull means 32 may be provided as part of the tunnel boring machine 18, or it may alternatively be provided as part of the apparatus 2. The cutting head 20 is a circular cutting head. The apparatus 2 includes mixer means 34 for mixing water and dry cement to form the wet cement 4. Associated with the mixer means 34 is a pump 36 for pumping the wet cement 4 at low pressure to the second conduit means 30. The second conduit means 30 includes a plurality of outlets 37 which are arranged in a circle. Wet cement from the outlets 37 passes to pumps 38 which operate at high pressure and which pump concrete to nozzles 40. The nozzles 40 inject the concrete around the outside of the tube 8 as shown in Figure 1. As can be seen from Figure 1, the tunnel boring machine 18 is used to tunnel through the ground 28 whilst an in-situ concrete tunnel lining 42 is formed at the rear of the tunnel boring machine 18. The drive means 22 is in the form of a drive motor which is mechanically attached to the tunnelling shield 24. The cut ground is removed as spoil via the first conduit means 26. The spoil which leaves the first conduit means 26 is then transported away from the tunnelling machine, either by rail or by a conveyor (not shown). The tunnelling shield 24 supports the cut ground 28 prior to the tunnel lining 42 being formed. The push/pull means 32 are in the form of piston operated rams. The push/pull means 32 is also mechanically attached to the tunnelling shield 24. As shown in Figures 1 and 3, there is a bulkhead 44 positioned between the outer surface of the tube 8 and the surface 46 which is left after the tunnel boring machine 18 has cut through the earth 28. The bulkhead 44 forms a sealed bulkhead between the outside of the tube 8 and the surface 46. Thus, the wet concrete 4 gets injected into the space between the outside of the tube 8 and the surface 46, and forms the tunnel lining 42. The pumps 38 are mechanically connected to the bulkhead 44, and thereby to the tunnelling shield 24. As indicated above, the liquid concrete is supplied to the pump 38 via the second conduit means 30 which is in the form of a supply pipe. The mixer means 34 is in the form of concrete batching plant 8. The ring members 10 are rigid and they resist the forces imposed by the ground 28 and the injected wet concrete 4. The wet concrete 6 is a fast setting fibre reinforced wet concrete 4. Once the wet concrete 4 sets, the tunnel lining 42 is formed and it is able to resist forces from the ground 28. During the operation of the apparatus 2, concrete is brought to the tunnel boring machine 18 by conveyor or train (not shown) in an un-wetted state. This dry concrete is placed in the mixer means 34. Water is added and the wet concrete is thoroughly mixed in the mixer means 34. The pump 36 pumps the wet concrete 4 via the second conduit means 30 to the pumps 38 which operate at high pressure. The pumps force the wet concrete 4 through the bulkhead 44 via the injector nozzles 40. As can be seen from Figure 1 , the area into which the wet concrete is injected from the nozzles 40 is sealed on all sides by the excavated ground 28, the bulkhead 44, the tube 8 and the already injected wet concrete 4 which will eventually dry to form the tunnel lining 42. As the wet concrete is injected, it compacts and then starts to build up pressure behind the bulkhead 44. If the push/pull means 32 is allowed to move freely, then the build up of pressure behind the bulkhead 44 is effected to push the tunnelling shield 24 forward and into the uncut ground 28. The pressure of the concrete behind the bulkhead 44, the pressure of the ground 28 against the cutting head 20, and the speed of movement of the tunnelling shield 24 through the ground 28 can be controlled by the speed of rotation of the cutting head 20, the rate of removal of spoil through the first conduit means 26, and the rate and pressure of the wet concrete injected from the pumps 38. As the tunnelling shield 24 moves forward, the push/pull means 32 will extend due to their connection to the static tube 8. Once the push/pull means 32 have reached their maximum travel, the injection of the wet concrete 4 can briefly be halted, and then the push/pull means 32 can be operated to retract the rams. This will thus pull the retaining ring 14 and the tubes 8 back into the tunnelling shield 24. The liner means 13 in the form of the plurality of flexible bands is placed around the outside of the tube 8 so that the flexible bands are in a line as shown. The series of flexible bands may be placed around the outer surface of the tube 8 when the elongate members 12 are retracted towards the tunnelling shield 24 by the retaining ring 14. The flexible bands forming the liner means 13 form a continuous girdle around the elongate members 12, and they are fed out behind the tunnelling shield 24 as the tunnelling shield 24 moves forward. When the tube 8 is again retracted up to the tunnelling shield 24, the friction between the concrete 4 and the flexible bands holds the flexible bands stationary to the concrete, whilst allowing the tube 8 to slide through the flexible bands. The end flexible band drops off the end of the tube 8, and is able to be brought forward to be repositioned on the now exposed portion of the tube 8 within the tunnelling shield 24. The flexible bands may be bent or made in two parts in order easily to pass through the retaining ring 14. The purpose of the liner means 13 in the form of the flexible bands is to prevent the elongate members 12 from scouring against the concrete 4 as the elongate members 12 slide through the concrete 4. In addition, the liner means 13 reduces friction, and evens out transmitted concrete pressure. The flexible bands may be made of any suitable flexible impact-resistant material such for example as rubber. As the tunnelling shield 18 advances, the cut surface 46 of the ground 28 is retained by the drying wet concrete 4. The pressure of the cut ground 28 and that of the wet concrete 4 is transferred to the tube 8 and the ring members 10. The number of the ring members 10 can be chosen in dependence upon the anticipated pressure and the need to avoid distortion of the tube 8. The ring members 10 can be pushed into position in the tube 8. In tunnel curves, the elongate members 12 forming the tube 8 are able to follow the curvature of the cut tunnel wall. The ring members 10 are able to slide along side each other to adjust for differences in lead between the inside wall and the outside wall of a curve. As the elongate members 12 slide alongside each other to adjust for the lead, the ring members 10 are able to roll within the tube 8, whilst still accurately maintaining the internal diameter of the tube 8. The length of the tube 8 may be governed by the speed of travel of the tunnelling shield 24 and the setting time of the wet concrete 4. For example, if the tunnelling shield 24 were to travel through the ground 28 at a speed of 5 metres an hour, and if the concrete setting time were to be 5 hours, then the tube 8 may need to be at least 25 metres long. For long tunnel length, the elongate members 12 may be made in two or more sections. Thus each section may be, for example, two metres in length. The various sections may be connected together by male and female screw connectors. During operation of the apparatus 2 and the tunnel boring machine 18, accurate control of the pressure of the injected wet concrete 4 through the bulkhead 44 allows natural ground pressures to be equalized, resulting in little or no settlement of ground during and after construction of the concrete tunnel 6. It is to be appreciated that the embodiment of the invention described above with reference to the accompanying drawings has been given by way of example only and that modifications may be effected. Thus, for example, the elongate members 12 may be hollow instead of solid, and they may have a different cross sectional shape to that shown. Similarly, the retaining rings 14 may have a different cross sectional shape to that shown. The elongate members 12 may each be formed in two or more sections, and the sections may be connected together by connector means such for example as screw connector means.

Claims

1. Apparatus for supporting injected wet concrete during the formation of a concrete tunnel, the apparatus comprising a tube and a plurality of ring members positioned inside the tube, and the apparatus being such that in use the wet concrete is injected around the outside of the tube and is supported by the tube until the wet concrete dries and becomes self- supporting, the ring members prevent the tube collapsing inwardly due to external pressure, the tube is formed by a plurality of elongate members which extend longitudinally and which are arranged side by side in a circle, the ring members extend transversely across the tube, and the elongate members are flexible and movable relative to one another thereby enabling the tube to bend and allow the concrete tunnel to be formed with curves.

2. Apparatus according to claim 1 in which the elongate members are rods.

3. Apparatus according to claim 1 or claim 2 in which the elongate members are circular in cross section.

4. Apparatus according to any one of the preceding claims in which the elongate members are each formed in one single piece.

5. Apparatus according to any one of claims 1 - 3 in which the elongate members are each formed in at least two sections which are connected together by connector means.

6. Apparatus according to claim 5 in which the sections are connected together by screw connector means.

7. Apparatus according to any one of the preceding claims which the ring members are solid, and circular in cross section.

8. Apparatus according any one of the preceding claims and including attachment means for attaching one end of the tube to a tunnel boring machine.

9. Apparatus according to claim 8 in which the attachment means is a retaining ring.

10. Apparatus according to claim 8 or claim 9 in which the elongate members are attached only to the attachment means, and not to each other.

11. Apparatus according to any one of the preceding claims and including liner means positioned around the outer surface of the tube.

12. Apparatus according to claim 11 in which the liner means is a plurality of flexible bands.

13. A tunnel boring machine when provided with apparatus according to any one of the preceding claims.

14. A tunnel boring machine according to claim 13 and including a cutting head, drive means for driving the cutting head, a cylindrical tunnelling shield, first conduit means for removing spoil from the cutting head, second conduit means for providing the wet concrete, and push/pull means for pushing the cutting head fowardly for cutting purposes and for pulling the tube up to the cutting head for wet concrete support purposes.

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15. A tunnel, boring machine according to claim 14 in which the cutting head is a circular cutting head.

16. A tunnel boring machine according to claim 14 or claim 15 and including mixer means for mixing water and dry cement to form the wet cement, and pump means for pumping the wet cement to the second conduit means.

17. A tunnel boring machine according to any one of claims 14 - 16 in which the second conduit means includes a plurality of outlets arranged in a circle.

18. A tunnel boring machine according to any one of claims 14 - 17 in which the drive means is a hydraulic drive motor.