CA1142862A - Flexible tubing - Google Patents

Abstract

A B S T R A C T

A FLEXIBLE TUBE FOR USE IN PARTICULAR IN
UNDERGROUND MINING

A flexible tube for use in underground works by producing a force and shape locking connection between constructions and the ground after the hardening of a filler introduced into the tube.
The tube is woven from synthetic fibres having a tear strength of at least 70 cN/tex without a seam.
The fabric of the tube is water-permeable and the tube is provided with a water-tight finish which partly seals the pore of the fabric.

Description

~L~IL42~Z

The present inven-tion relates to a flexible -tube made of a wa-ter per~lleable woven fabric, produced from high-strength synthetic fibres. Such tubes are used in particular in underground mining, in which af-ter introducing a hardening filling to the tube and after har~ening of this filling, -the tube provides a force and shape locking connection between the constructions and the ground.
A tube of thls type is known from German Patent No. 2,627,256. The known tube should be positioned while folded in the section of the pre- -assembled support arches such that when filled wi-th a hydraulic filler, for exa~nple concrete, grout, or the like, it opens in a fan'shape and fills the in-ternal space between the arches and the grounds' excavation line. As a result of the water-permeability of the woven fabric, the liquid of the hydraulic filler should escape outwards through the tube wall without the loss of any binders; the hardening process ~; 20 of the filling should -thereby be accelerated and after a short time, a sufficiently high green strength of, for example-, from ~0 to 50 kp/cm should be achieved.
The term "high-strength synthetic $ibres" is understood to designate wet, dry'or in particular melt spun fibres, spun from synthetic polymers, for example polyamides or polyes-ters, whereby the tearing streng-th of the fibres, which are usually in the form o~ con-tinuous filament-yarns, should be at least 65 cN/tex. German Paten-t No. 2,627,256 specifies high-strength polyethylene terephthalate threads (i.e. continuous filament yarns) as a suitable Illaterial for tubes with a diameter of up to approxi-mately 25 cm.
Experiments using the known tubes have shown tlla-t in the case o~ excavation with a diameber o~
- 10 more than approximately 4 m and also with tube diametérs of approximately 23 cm and more, increased demands are made both on the textile tube material as well as on the -tube construction and tube finish, in order on the one hand to impart an adequately high strength to the tube to allow a sa~e filling procedure and ensure an adequate support function during the hardening phase o~ the filler, and on the other hand to ensure the correct pore size~which allows the liquid but not the solid substances of the ~iller to penetrate outwards through the tube wall.
Moreover, it has been shown that even with an extremely care~ul working over compartively long dri~ts, the excavation cannot be ~ade so exact that`
the excavation line ex-tends at all points at less than approxin~a-tely 20 cm above the arches. Larger internal spaces always occur in particular in disturbed dri~ts, in which -the tube cannot rest against the ground non-~1~2~

positively and positively after i-t has been filled.
In order to effectively deal with such over~
excavations, it is obvious as a precaution, -to use tubes with a subs-tan-tially larger diameter~ Such tubes are thus expensive -to produce on account of the greater requirement of synthetic fibres, and lead to a great increase in the amount of fillers required during -their installation~ because the tube has to be tightly filled at all points.
An obJec-t of the invention is to overcome the disadvantages established with the known tubes and to provi~e flexible tubes to support for exampleJ
galleries, tunnels and the like. Such tubes are to be easy to fill--where there are lalrger supportlng 1~ arch diameters and/or a larger tube diameter and which may completely fulfil their support task even where there is an unforeseen over-excavation, without having to be overdimensioned`from the beginning.
According to the present invention there is provided a fleixble tuhe of a water-permeable woven fabric produced from high-strength synthetic fibres, for producing a ~orce and shape locking connection between constructions and in underground works by the hardening of a hardenable filling introduced into the tube, wherein the tube comprises synthetic fibres having a tear strength of at least 70 cN/-tex, is woven withou-t a seam and has a water-tight finish which partly seals the pores of the fabric.

~2 Known polyester filament yarns may be used as syntlletic fibres with a tear streng-th of at least 70 cN/tex, in particular polyethylene terephthalate yarns with a tear strength of at least 73 cN/tex.
: 5 If the flexible tube according to the invèntion is to be used in underground mlning where increased safety requirements are made with respect to its behaviour in fire and its surface resistence, a tube made of polyamide fibres i.s recommended, in particular of polyhexatnethylene adipic acid amide filament yarns with a tear strength of at least 73 cN/tex.
In order tlla-t on the one hand, the tube is inserted properly into the profile of the pre-assembled support arches and on the other hand, adapts as well as possible -to the irregular profile of the excavation line, during the filling proceduref the tube according : -to the invention is preferably made of synthetic fibres having an elongation at break of at least :19~. Synthetic fibres with a reference elongation of at least i2% at a s-train of 48 cN/tex are particularly fa~ourable with regard to the behaviour of the tube during the filling procedure (until the filler hardens);
this reference elongation is established under a strain f 90 N with a yarn ti-tre of 1880 dtex which is particularly sui-table for the tube production for reasons of strength and water.permeability.

Zr~

Polye-thylene terephthalate or polyhexamethylene adipic acid anlide fibres are usually adequate -for tube diameters of up to approximately 50 cm. The strength of these fibres may be increased to as much as 100 cN/tex or more by way of the polymerisation, spinning and drafting conditions. For larger tube and/or supporting arch diameters ~hich are associated with greater filling pressures or tube lengths, the resistance strength and stability of the tubes may be further increased in that cords are produced from the polymeric fibres mentioned and these are processed into heavy cord fibrics. In order to be able to retain lighter tube weights with such tube dimensions, it is advisable to produce the tube at least in the weft from aramide yarns(yarns made from aromatic polyamides) with a tear strength of at least 170 cN/tex. Tear s-trengths of 180 cN/te~ or more arè
preferred. When using aramide yarns in the weft, it is at times adisable to arranged the warp threads such that they protect the weft yarns àll round from damage, abrasion and the like. This may be effected, for example, by a twill weave.
- Tubes made of aramide yarns have, in addition to their high s-trength, a more favourable burning behaviour which is essential in particular for use underground.
Initially the use of flexible tubes produced from normal woven fabrics was tried. The tubes were :
formed-by folding a fabric web along the centre thereo-f and sewing toget;her the two edges which were thereby superimposad.
In operation, this seam provided -to be a .
critical weak point in the -tubes. For this reason, the tubes according to -the invention are to be-woven "wi-thout a seam", i.e. woven fabrics are to be used ; which contain a fillable space due to their construct-ion.
~ The fle~ible tube is woven flat for reasons of cost as well as on account of a number of construc-tional advantages ob-tainable therewith9 and it has two dimetrically positioned longitudinal flanges of at least 1 cm in wid-th on its circumference.
As a result of flat weaving,~several fabric $ubes may be simultaneously produced over large widths which are separated from each other by cross-pieces of a pre-determinable width; the tubes are then separated from each other along these cross-pi~ces.
The longitudlnal flanges which result and are positioned on the rlght-and left-hand side of each flat woven tube offer a substantially increased strength compared with thq conventional seams; they simultaneously stabilise the tube position during the filling prooedure and indicate whe-ther the tube has become twisted w~ile being inserted into the construction profile.
~ith flat weaving, it is also possible -that, instead of using quasi-continuous tubes which subsequently have to be cut to the required length and sealed at their ends, continuous transverse cross-pieces of a few centimetres in width are woven in, at intervals spaced by -the required tube length; when the tubes are separated from each other along 'these -transverse flanges, another preferred tube shape is thereby obtained hav~ng transverse flanges of at least 1 cm in width on both fron-t faces. Tubes of this type may be inserted into the construction pro-file without further preparation and may be furnished with and -filled by a support filling which penetrates the fabric.
Another method for the production of seam-less tubes is by weaving on a circular loom (tubular weaving). During this process however, it is only possible to produce one individual, quasi-continuous tuber per loom, which tube then has -to be cut to length. The ends o~ the tube must then be sealed, which r3ay be effected, for example, by stringing, like sausage skins. In the case of circular woven tubes, the front ends are preferably -folded together and are sewn forming a transverse flange which is at least 1 cm wide (optionally after turning over once or twice), then clamped or tightly sealed in a similar manner.

The tubes may be woven in various weave forms.
The twill weave has already been men-tioned. The Panama weave (for example 1~ ~ is particularly suitable for most purposes, because ~irstly it allows the thread density required for the strength (number of threads ~er cm of fabric width), and secondly, it provides a higll tear propagation s-trength and has openings between the constan-t groups of threads which promote t1le water-permeability of the fabric.
It is appropriate for underground use of the tubes according to the invention if the water-tight fi~ish provides an antistatic effect such that the surface resistance (according to DIN 5~1 345~ of the tube is less than lO7~ preferably less than lO
__r~
The water-tight finish may be applied after the fabric -tube has been producecl. However, it may also be applied on the individual filal!lent yarns during the yarn production or during the we~ving procedure.
In order to achieve the low surface resistances - mentioned above more easily~, it may be appropriate for the synthetic fibres of the tube to contain antistatic, i.e. conductive additives by, for example, spinning in a few percent by weight of carbon black or the fibres having a core-shea-th struc-ture with a conductive component as the core.
When an unde~ired over-excavation is to be ~1~2~

reckoned on, a tube designed as a multiple -t~be is preferred, in which at least two tubes woven without a seam are firmly joined together. Thereby, two, three or more tubes may be firmly joined together while superimposed and/or adjacently. The multiple tube is preferably a double tube which consists of two superimposed -tubes, woven without a seaml When carrying out the d~if-t construction, the tubes which are flattened together are inserted, the lower one at the very bottom, into the channel profile of the -construc-tion arch and the lower tube is filled first of all, until it rests against the largest part of the excavation line, in a tightly filled condition. The upper tube which is unfiIled is t~lereby squeezed in between the lower tube and the ground. In the places of over excavation, the upper tube in each case is punctured using a filling lance and this -tube section is filled until the upper tube also rests against the excavation line, being tightly filled. Thus, with such an embodiment of -the invention, -the upper tube is therefore only filled locally where it is really necessary. The upper tu~e is ~inched o-ff from the filled lower tube and from the ground at the remaining places, so tllat the flller only fills the places of over excavation.
If tllree, four or more tubes are used, then in prlnciple the same course of action is taken. The ~4Z~

- ii lowest tube in each case is firs-tly tightly filled, the next tube in each case is only filled where necessary at -the places o:f over excava-tion.
The use of two or mdre small tubes instead of one large tube has the advan-tage tha-t substantially-fewer synthetic fibres are required, because, for strength reasons, where there are larger tube diameters, an increased square metre weight (higher thread density) is required. Another advan-tage is the possibili-ty oI only having to use additional filling material at the places of over-excavation.
The diameter of -the individual tubes firmly joined -together lllay be the same or different. Since the higher positioned tube in each case should only be a reserve (-for the points of over-excavation), tubes having varying diameters are preferred. The higher positioned tube in each case is then usually given a smaller diameter.
The firm join bet-~een the individual tubes of the multiple tube according to the invention may be obtained for example, by bonding the folded individual tubes flat on top of each other. A join in terms of weaving of the individual tubes is more stylish in -terms of production and less problematic for furtller processing, because it is more stable.
Thus, the individllal tubes of the multiple tube may be woven together in particular at binding points, 114~

i.e. the warp threads of neighbouring tubes are bonded together.
Flat weaving is particularly suitable for the production oI the mul~iple tubes according to the invention, whereby the individual tubes, as described in the main application, may have diametrically positione~ longitudinal flanges.on their circumference which increase the strength and simplify the filllng : : procedure.
. Embodiments of the present invention will now be described by way of example, with reference to .
the accompanying drawings, in which: ~
Figure l. is a schematic front view of a drift construction with a tube according to the invention; -Figure 2. schematically illustrates a cross-section : through a flat woven web having several fabric tubes joined by longitudinal cross-pieces;
Figure 3. schematiDally illustrates a cross-section : through a tube provided w th longitudinal~la~ges and . 20 filled with concrete; and Figure 4. schematically illustrat~s a front end of a flexible tube according to the invention with a turned-over transverse flang;~
Figure ~. is a schematic front view of a drift construction with a.traditional tube which does not rest against the excavation line ln the region of a over-excavation;

,.

~L14~ 2 Figure 6. illustrates a section through the construction according to Figure 5 along the ~ine VI-VI;
Figure 7 is a schematic front view of the drift construction according to Figure 5 with a multiple tube according to the invention;
Figure 8 illustrates a section through the extension according to Figure 7 along the line VIII-VIII;
Figure 9 to Figure 11 are schematic illustrations of some multiple tubes according to the invention, (a) in the flattened condition and ~b) in an installed condition;
Figure 12 and Figure 13 illustrates two further multiple tubes shown schematically in flattened condition.
Figure l schematically illustrates a drift construction. The excavation 1 has an irregular excavation line 2. Steel supporting arches 4, o.f example, channel sectlons according to Figure 1 or Figure 2 of German Patent No. 2,627,256 are positioned at a spacing of approximately from 10 to 20 cm from the ground 3; a flexible tube 5 according to an embodiment the invention is inserted between.the ground ~3 and construction arch 4 and is expanded by filling with a hardening material,-e.g concrete, so that it produces a substantially force and shape locking connection between the ground 3 and construction arch 4. The filling opening 6 may be in the roof of the construc-tions, as is shown ~:L4;~

_ 14 - -Figure 2 schematically illustrates a section cut through a flat woven web compr-sing several fabric tubes 7,8 and 9, whereby woven longitdunal cross- pieces 10 and 11 are provides between the ~5 individual fabr:ic -tubes 7,8 and 9. By dividing the web along -these cross-pieces, -tubes which are woven without a seam are produced. .
Figure 3 represen-ts again greatly schematized a fabric tube 12 with two longitudinal flanges 1~
: : 10 positioned diame-trically with respect -to each other and this is in a oondition in which the tube is : tightly filled with concrete 14.
Finally, Figure ll illustra-tes in longitudinal section, a Iron-t end of a p:referred embodiment of the tube according to the invention, in this case a circular woven -tube 15. The end of this tube 15 is folded and -turned over andi sewn, clamped or the lihe, so tha-t the -tube 15 has at i-ts end a thick~
transverse flange 16 of at least 1 cm width.
Figures 5 and 6 illustrates a drift constructlon ~: in which there is a flexible t~be-24 filled with concrete 23 between the ground 21 and the construction . arch 22. Part of the excavation line 25, as seen from Figure 5 (see the-left-hand or right hand edge) occurs at such a small distance from the ext0nsion arcli 22 tha-t the tigh-tl~ filled tube 24 forms a force and shape locking connection bet~een the ground ,. .

- ~i4~6~ --.

21 and construction arch 22 (see Figure 6).
~n the centre of Figure 5, the excavation line 25 is at such a distance from the construction arch 22 -that the tube 2~ cannot rest against the ground 21 in spite of being completely filled to its greatest diameter. In this case, there is an undeslred over-excavation 26, whose exsistence endangers the safety of the total construction and is to.be removed by : ~ means of the invention.
~: 10 How this problem is solved by means of the~
invention is illustrated in Figures 7 and 8. Thus, a multiple tube MS is in-troduced between the-construction arch 22 and ground 21. This multiple tube MS comprises a lower tube 27 which , in the present example, has the same dimensions as the tube'2l~ in Figure 5 or Figure 6, an,d an upper tube 28 firmly connected with this tube with a smaller diameter than the tube 27.
, The lower tube 27 is filled first of all, until i~
. rests a~ainst tl~e excavation line 25 in a tightly filled condition (see Figure 5). The upper tube 28 which is still unfilled is thereby clamped between the tube 27 and ground 21 and lies over tube 27 (Pos. 28').
. A filling lance is stuck into the upper tube 28 at the point of the over-excavation 26 and is filled with concrete until the upper tube'completely res-ts against the ground.

,:' . ~ .

.

~ ~ Z~ ~ 2 In Figures 9 to 13 some examples, o~ multiple tubes are shown, so tha-t it might be seen -that the multiple -tube may also have a construction which di~fers from tha-t shown in Figures 7 and 8 The multiple tube shown in Figure 9 conslsts of -two tubes 29 and 30 which have different dimensions and are firmly joined together at a common binding point 31 and have lateral flanges ~2.
Figure 10 illustrates a triple tube, consisting of three superimposed tubes 33,34,35 of which the lowest tube 33 has -the largest diameter.
Figure ll illustrates a triple tube consisting o~ two tubes 37 and 38 which are secured adjacent to one another to a lower tube 36.
i5 As may be seen from Figure 12, it is possible to produce a multiple tube ~rom a larger dimensioned tube 39 by weaving in at least one cross piece 40~
Finally, Figure 13 illustrates a quadruple tube, consis-ting of two larger tubes 4i and 42 and two smaller tubes 43 and 44 which are positioned between these larger tubes 41 and ll2.
The fleixble tube according to the invention are preIerably used in underground mining for drift -construction. However, they may also be used in the mining o~ ~or example minerals, salts or ores or may be used in tunnelling work.

Claims (18)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A flexible tube of a water-permeable woven fabric produced from high-strength synthetic fibres, for producing a force and shape locking connection between constructions and ground in underground works by the hardening of a hardenable filling introduced into the tube, wherein the tube comprise-s synthetic fibres having a tear strength of at least 70 cN/tex, is woven without a seam and has a water-tight finish which partly seals the pores of the fabric.

2. A flexible tube according to claim 1, wherein the tube consists of polyhexyamethylene adipic acid amide filament yarns having a tear strength of at least 73 cN/tex.

3. A flexible tube according to claim 1 wherein the tube consists of synthetic fibres which have an elongation at break of at least 19%.

4. A flexible tube according to claim 1, 2 or 3, wherein the tube consists of synthetic fibres which have a reference elongation of at least 12% at a strain of 48 cN/tex.

5. A flexible tube according to claim 1, wherein the tube has aramide filament yarns, at least in the weft, with a tear strength of at least 170 cN/tex.

6. A flexible tube according to claim 1, wherein the tube is woven flat and has on the circumference thereof two diametrically located longitudinal flanges of at least 1 cm in width.

7. A flexible tube according to claim 6, wherein the tube has transverse flanges of at least 1 cm in width on both ends thereof.

8. A flexible tube according to claim 19 wherein the tube is woven on a circular loom and has transverse flanges of at least 1 cm in width on both ends thereof.

9, A flexible tube according to claim 1, wherein the tube is woven in Panama weave.

10. A flexible tube according to claim 1, wherein the water-tight finish provides an antistatic effect such that the surface resistance (according to DIN
54345) of the tube is less than 107?.

11. A flexible tube according to claim 10, wherein the water-tight finish provides an antistatic effect such that the surface resistance of the tube is less than 106?.

12. A flexible tube according to claim 10, wherein the tube is woven from filament yarns with a water-tight, antistatic finish.

13. A flexible tube according to claim 10, 11 or 12 wherein the tube comprises synthetic fibres which contain antistatic additives.

14. A flexible tube according to claim 1 wherein the tube is a multiple tube, in which at least two tubes woven without seams are firmly joined together.

15. A flexible tube according to claim 14, wherein the multiple tube is a double tube which comprises two superimposed tubes woven without seams.

16. A flexible tube according to claim 14 or 15 wherein the tubes have different diameters.

17. A flexible tube according to claim 14 or 15, wherein the individual tubes of the multiple tubes are woven together at binding points.

18. A flexible tube according to claim 1, 6 or 14 for use in underground mining.