GB1575331A - Seals for tunnelling shields - Google Patents
Seals for tunnelling shields Download PDFInfo
- Publication number
- GB1575331A GB1575331A GB2668977A GB2668977A GB1575331A GB 1575331 A GB1575331 A GB 1575331A GB 2668977 A GB2668977 A GB 2668977A GB 2668977 A GB2668977 A GB 2668977A GB 1575331 A GB1575331 A GB 1575331A
- Authority
- GB
- United Kingdom
- Prior art keywords
- seal
- shield
- tail
- tunnelling
- brush
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000000463 material Substances 0.000 claims description 61
- 238000007789 sealing Methods 0.000 claims description 35
- 229920001971 elastomer Polymers 0.000 claims description 28
- 239000000806 elastomer Substances 0.000 claims description 28
- NMFHJNAPXOMSRX-PUPDPRJKSA-N [(1r)-3-(3,4-dimethoxyphenyl)-1-[3-(2-morpholin-4-ylethoxy)phenyl]propyl] (2s)-1-[(2s)-2-(3,4,5-trimethoxyphenyl)butanoyl]piperidine-2-carboxylate Chemical compound C([C@@H](OC(=O)[C@@H]1CCCCN1C(=O)[C@@H](CC)C=1C=C(OC)C(OC)=C(OC)C=1)C=1C=C(OCCN2CCOCC2)C=CC=1)CC1=CC=C(OC)C(OC)=C1 NMFHJNAPXOMSRX-PUPDPRJKSA-N 0.000 claims description 10
- 239000002184 metal Substances 0.000 claims description 10
- 229920001084 poly(chloroprene) Polymers 0.000 claims description 6
- 239000007787 solid Substances 0.000 claims description 5
- 239000004677 Nylon Substances 0.000 claims description 4
- 229910000639 Spring steel Inorganic materials 0.000 claims description 4
- 229910000831 Steel Inorganic materials 0.000 claims description 4
- 230000003190 augmentative effect Effects 0.000 claims description 4
- 230000004048 modification Effects 0.000 claims description 4
- 238000012986 modification Methods 0.000 claims description 4
- 229920001778 nylon Polymers 0.000 claims description 4
- 239000010959 steel Substances 0.000 claims description 4
- 229920003051 synthetic elastomer Polymers 0.000 claims description 3
- 239000005061 synthetic rubber Substances 0.000 claims description 3
- 229910001209 Low-carbon steel Inorganic materials 0.000 claims description 2
- 230000009471 action Effects 0.000 claims description 2
- 230000001419 dependent effect Effects 0.000 claims description 2
- 230000000694 effects Effects 0.000 claims description 2
- 230000002787 reinforcement Effects 0.000 claims description 2
- 229910001220 stainless steel Inorganic materials 0.000 claims description 2
- 239000010935 stainless steel Substances 0.000 claims description 2
- 229910000278 bentonite Inorganic materials 0.000 description 4
- 239000000440 bentonite Substances 0.000 description 4
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 4
- 230000007246 mechanism Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 229920002635 polyurethane Polymers 0.000 description 3
- 239000004814 polyurethane Substances 0.000 description 3
- 239000000725 suspension Substances 0.000 description 3
- 239000011440 grout Substances 0.000 description 2
- 230000009974 thixotropic effect Effects 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000006194 liquid suspension Substances 0.000 description 1
- 239000012858 resilient material Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
- E21D9/06—Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
- E21D9/0635—Tail sealing means, e.g. used as end shuttering
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Lining And Supports For Tunnels (AREA)
Description
(54) IMPROVEMENTS IN OR RELATING TO
SEALS FOR TUNNELLING SHIELDS
(71) We, EDMUND NUTTALL LI
MITED, a British Company of, 22, Grosvenor Gardens, London SW1W ODR, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement :
This invention relates to seals for tunnelling shields.
United Kingdom Patent Specification 1 083 322 describes and claims a method of tunnelling using a tunnelling apparatus including a shield containing or supporting a power drive rotary mechanical digging mechanism in front of a bulkhead, in which a liquid thixotropic suspension is delivered under pressure to the space in front of the bulkhead so as to contract the working face on which the digging mechanism acts, and the spoil excavated by the digging mechanism is removed together with a proportion of the liquid suspension.
This method has been coming into practical use for some years, and in practice, the thixotropic suspension is of Bentonite and the type of machine used is referred to as a bentonite tunnelling machine.
In using such a machine, with a high pressure at the working face, it is necessary to have a seal at the tail of the tunnelling shield to prevent leakage round the outside of the shield and into the rear thereof.
Hitherto, as described in U.K. Patent Specification 1 417 969, such a seal has been constituted by an annular brush type seal extending round and secured within the shield so that the brush itself bears and seals on the tunnel lining within the rearmost part of the shield. The brush may be applied against the lining by an inflatable pneumatic ring secured by straps to the shield.
Such a tail seal has provided an adequate seal in use, but suffers from the disadvantage that when the advancing jacks are relaxed, the pressure at the working face tends to push the shield away from the face so that the brush, which is formed of long fibres normally laid along the lining and extending rearwardly, is subjected to a reversal of its normal movement and rapidly becomes tangled, resulting in a loss of sealing. For this reason, brush seals at the tail have had to be frequently replaced.
Accordingly the present invention consists in a seal for a tunnelling machine, including a resiliently supported annular sealing member carrying a sealing surface of short brush-form material (as hereinafter defined), the said sealing member being arranged to be resiliently urged into engagement with a co-operating surface, preferably by means of an annular body of closed cell expanded elastomer material, such as a synthetic rubber.
The invention is applicable to the stiff trailing lip type of seal, and also for example to a seal consisting of a ring of flexible material anchored at the leading and trailing edges and carrying a brush type sealing surface. The ring covers an annular body, of closed cell neoprene which is compressed by the ring so as to urge the ring outwardly towards the corresponding surrounding surface.
If desired the body of closed cell material may include one or more inflatable zones embedded therein.
The use of short brush material at the sealing surface gives a seal which conforms to the somewhat irregular surface to be found on the exterior of the tunnel lining.
The brush material is to be mounted on a robust steel or tough elastomer sealing member, and the use of closed-cell expanded elastomer to urge the sealing member against the lining provides resilient urging without the possibility of grout or other material impairing the operation of the resilient urging means, as could happen if inflatable tubes or mechanical springs were used.
Short brush form material, which is defined as brush material of which the fibres are sufficiently short and fine to be bistable in operation so as to flick over from one stable position to the other on a reversal of stress, has not previously been used for sealing in tunnelling machines. It has been used as a weather seal for doors and sliding windows when the conditions are less arduous, and it has surprisingly been found that it is able to stand-up to the conditions to which a tunnelling machine seal, particularly a tail seal on a bentonite machine, is subjected. The short fibres need to be closely bunched together to form an effective barrier to the flow of bentonite suspension or other materials against which sealing is desired.It is also clear that by using short material, the tangling problem met with in long brush fibres is also avoided in that the fibres flick over to the alternate position on a reversal of motion.
A further advantage arising is that a long fibre brush is susceptible to considerable damage if some of the fibres are allowed to set into grouting. The length of the fibres means that a considerable force has to be exerted to free the fibres and this force may break the fibres or pull them out of the anchorage. If short fibres are set in grout then the force involved is smaller and therefore less damage to the seal occurs from this cause.
The seal will normally be mounted within a shield to bear on a tunnel lining within the shield.
According to a second aspect of the invention there is provided a tunnelling shield having a tail seal as set forth above mounted thereon.
An annular trailing lip seal is preferably made in sections, e.g. four in number each covering 90 , lap-jointed together.
The trailing lip sealing member may be formed of a solid polyurethane.
In a preferred embodiment, the tail seal is duplicated to provide a rear tail seal in tandem with a forward tail seal. The rear tail seal in such an arrangement may be formed by a lip seal at the sealing surface, rather than by a brush.
The invention will be further described with reference to the accompanying drawings which show various embodiments of the invention, and in which :
Figure 1 is a diagrammatic section, to a reduced scale, on the line I-I of Figure 2;
Figure 2 is a sectional view to an enlarged scale drawing on the line II-II of Figure 1, showing a form of tail seal according to one form of the invention;
Figures 3 to 6 are views similar to Figure 2 showing alternate forms of embodiment; and
Figure 7 is an isometric view illustrating a joint between sections of a tail seal.
Turning first to Figures 1 and 2 there is shown the rear portion 1 of a tunnelling shield which is provided with a recess 2 for housing a tail seal. The tail seal consists of a body 11 of durable resilient material such as moulded polyurethane with Shore hardness of about 80, which is provided with metal inserts 13 by which it can be securely screwed to the shield 1. A portion 4 of the body 11 is arranged to be spaced from the shield 1, and the space so formed is filled with a body 14 of closed cell expanded elastomer, such as expanded neoprene. The body 11 thus forms a stiff trailing lip seal.
The sealing face of the portion 4 is provided with a sealing surface, which is illustrated as being in the form of a continuous brush element extending around the ring shaped body of the seal. A typical commercially available material consists of closely packed nylon bristles 15, e.g. 16mm long, set in a polyurethane base 16. The bristles are short enough and firm enough to be bistable so as to take up an inclined trading position for each direction of motion and to flick from one position to the other on a reversal of motion. The sealing surface is indicated by the reference numeral 8, and screws indlcated by 9 are placed at intervals around the ring to hold the sealing surface in place. The back 16 is retained in the body 11 by means of metal strips 17.
For the particular application for which this seal is designed, the tunnel lining is not exactly co-axial with the tunnelling machine, so that the sealing is not required on a circle, but is in fact slightly flattened at the top. In order to accommodate this variation, the portion 4 of the body is thicker as indicated at 11 in Figure 1 at the top of the tunnel than at the bottom.
If desired, a second or forward tail seal may be provided in a further recess.
The seal here is essentially similar to that already described, and detailed description will not be given.
In order to keep the pieces of the seal down to manageable size, and also to improve its deflectability it is preferred that the tail seal body should be made in sections, e.g. four in number each covering a 90" arc. The joints between the sections are illustrated in Figure 1 by lines 51, and it can be seen from Figure 7 that adjacent the joint lines, the sections of the body are rebated to provide a lap joint as indicated at 52.
Turning now to Figure 3, there is shown a stiff trailing lip seal in which the trailing lip itself is formed by fabric reinforced elastomer material similar to that used for conveyor belting. The body 18 illustrated is formed of two layers of such conveyor belting material, each 3/8 inch thick and bonded together. The body 18 is again held down to the tunnelling shield 1 by screws (not shown) which pass through mild steel flaps 19 which not only serve to protect the material of the body 18, but also function in the same way as the strips 17 to engage and protect the leading edge of the back 16 supporting the brush material 15. The body 18 is urged in the sealing direction by means of a body of expanded neoprene 14. It will be seen that this seal is also a stiff trailing lip type of seal.
Figure 4 shows a different form of seal in which both the leading and trailing edges of the seal are anchored. A wide strip 21 of short brush material, e.g. 16mm nylon or similar brush material, set in a steel or elastomer back 22 has the back 22 anchored at both leading and trailing edges by means of screws 23 set at appropriate spacings around the periphery of the seal. These screws pass through fixing strips 24, the back 22 and into securing blocks 25. The securing blocks may vary in height around the periphery of the tunnelling shield 1 to provide proper spacing of the brush material 21 from the tunnel lining.
Within the cavity defined between the brush back 22 and the tunnelling shield 1, there is located a body 26 of closed cell expanded elastomer material in a partially compressed state so as to urge the brush material into engagement with the surface against which it is to seal, and the effect of this material is augmented by an inflatable expansion ring 27, which may be formed from 150mm flat hose, similar to that used for fire hoses.
In the embodiment of the invention shown in Figure 5, a stiff trailing lip seal is provided by a spring steel lip 31 secured at is forward end by screws 32a to mounting block 32 themselves mounted on the tunnelling shield 1. The lip 31 carries, in a cavity provided for the purpose, the backing 32 of short brush material 33, and is urged towards the outer position shown in full lines by an annular means 34 of closed cell expanded elastomer material, e.g. expanded neoprene.
Figure 6 shows the rear portion of a tunnelling shield provided with a recess 2 housing a rear tail seal and also shows a portion of a second recess 12 for housing a forward tail seal (not shown). The tail seals are generally similar to those described with reference to Figure 2 above, with certain modifications.
The forward ends of the tail seal body sections are linked by a ring 42 of wire rope for reinforcement.
Further the body 11 is reinforced with expanded metal sheet 44 embedded in the moulded material as indicated.
Various other modifications may be made within the scope of the invention. For example, the brush form material may have the fibres looped through a thick body, e.g.
1/2 inch thick, of fabric-reinforced elastomer and the loops on the reverse side may be secured by wire, e.g. of stainless steel.
WHAT WE CLAIM IS:
1. A seal, and especially a tail seal, for a tunnelling machine, including a resiliently supported annular sealing member carrying a sealing surface of short brush form material, (as hereinbefore defined), and means for resiliently urging the said sealing member into engagement with a co-operating surface.
2. A seal as claimed in claim 1, in which the said urging means consists of an annular body of closed cell expanded elastomer material.
3. A seal as claimed in claim 2, in which the annular body is of synthetic rubber.
4. A seal as claimed in claim 1, 2 or 3, in which the sealing member is a stiff trailing lip seal.
5. A seal as claimed in claim 2 or 3, in which the sealing member is a body of solid elastomer material adapted to be secured in one region to the tunnelling shield and to have a second region in the form of a trailing lip spaced from the shield, with the body of closed cell expanded elastomer material located in the space between the shield and the lip.
6. A seal as claimed in claim 5, in which the surface of short brush form material is mounted on a backing held in place on the lip by metal strips.
7. A seal as claimed in claim 5 or 6, in which the body of solid elastomer material is reinforced by expanded metal.
8. A seal as claimed in claim 4, in which the sealing member is a body built up from layers of fabric-reinforced elastomer material bonded together.
9. A seal as claimed in claim 8, in which the surface of short brush form material is mounted on a backing held in place by metal flaps which also extend across the expanded surface of the fabric-reinforced elastomer material.
10. A seal as claimed in claim 4, in which the sealing member is a spring steel lip.
11. A seal as claimed in claim 1, 2 or 3, in which the sealing member has its leading and trailing edges anchored to the shield and is held spaced from the shield between these edges by the resilient urging means.
12. A seal as claimed in claim 11, as dependent on claim 2 or 3, in which the action of the expanded elastomer material is augmented by an inflatable expansion ring.
13. A tail seal as claimed in any of the
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (19)
1/2 inch thick, of fabric-reinforced elastomer and the loops on the reverse side may be secured by wire, e.g. of stainless steel.
WHAT WE CLAIM IS:
1. A seal, and especially a tail seal, for a tunnelling machine, including a resiliently supported annular sealing member carrying a sealing surface of short brush form material, (as hereinbefore defined), and means for resiliently urging the said sealing member into engagement with a co-operating surface.
2. A seal as claimed in claim 1, in which the said urging means consists of an annular body of closed cell expanded elastomer material.
3. A seal as claimed in claim 2, in which the annular body is of synthetic rubber.
4. A seal as claimed in claim 1, 2 or 3, in which the sealing member is a stiff trailing lip seal.
5. A seal as claimed in claim 2 or 3, in which the sealing member is a body of solid elastomer material adapted to be secured in one region to the tunnelling shield and to have a second region in the form of a trailing lip spaced from the shield, with the body of closed cell expanded elastomer material located in the space between the shield and the lip.
6. A seal as claimed in claim 5, in which the surface of short brush form material is mounted on a backing held in place on the lip by metal strips.
7. A seal as claimed in claim 5 or 6, in which the body of solid elastomer material is reinforced by expanded metal.
8. A seal as claimed in claim 4, in which the sealing member is a body built up from layers of fabric-reinforced elastomer material bonded together.
9. A seal as claimed in claim 8, in which the surface of short brush form material is mounted on a backing held in place by metal flaps which also extend across the expanded surface of the fabric-reinforced elastomer material.
10. A seal as claimed in claim 4, in which the sealing member is a spring steel lip.
11. A seal as claimed in claim 1, 2 or 3, in which the sealing member has its leading and trailing edges anchored to the shield and is held spaced from the shield between these edges by the resilient urging means.
12. A seal as claimed in claim 11, as dependent on claim 2 or 3, in which the action of the expanded elastomer material is augmented by an inflatable expansion ring.
13. A tail seal as claimed in any of the
preceding claims, in which the ring is made in sections lap-jointed together.
14. A tail seal as claimed in claim 13, in which the sections are linked by a ring of wire rope.
15. A seal as claimed in any of the preceding claims, in which the short brush form material is formed of nylon bristles moulded or mounted in a base of elastomer material or steel.
16. A tunnelling shield having a tail seal mounted thereon, in which the tail seal is as claimed in any of the preceding claims..
17. A tunnelling shield as claimed in claim 16, in which the tail seal is mounted in a recess in the outer surface of the shield.
18. A tunnelling shield as claimed in claim 16 or 17, which has a rear tail seal in tandem with a forward tail seal, with each of said tail seals being according to one of the claims 1 to 14.
19. A tail seal for tunnelling machine substantially as hereinbefore described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2668977A GB1575331A (en) | 1976-07-29 | 1977-07-14 | Seals for tunnelling shields |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3162476 | 1976-07-29 | ||
| GB367377 | 1977-01-28 | ||
| GB2668977A GB1575331A (en) | 1976-07-29 | 1977-07-14 | Seals for tunnelling shields |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1575331A true GB1575331A (en) | 1980-09-17 |
Family
ID=27254309
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB2668977A Expired GB1575331A (en) | 1976-07-29 | 1977-07-14 | Seals for tunnelling shields |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1575331A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2608714A1 (en) * | 1986-12-17 | 1988-06-24 | Fives Cail Babcock | Sealing gasket for a machine for boring out tunnels or galleries |
| GB2235230A (en) * | 1989-08-26 | 1991-02-27 | Eickhoff Maschf Eisen | A bracing device for a self-advancing shield tunnelling machine |
-
1977
- 1977-07-14 GB GB2668977A patent/GB1575331A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2608714A1 (en) * | 1986-12-17 | 1988-06-24 | Fives Cail Babcock | Sealing gasket for a machine for boring out tunnels or galleries |
| GB2235230A (en) * | 1989-08-26 | 1991-02-27 | Eickhoff Maschf Eisen | A bracing device for a self-advancing shield tunnelling machine |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |