CA2264891A1 - Device and method for filling a bag with a fluid material and bag suited for this purpose - Google Patents

Abstract

The invention concerns a device for continuously filling with a hardening material a bag (2) elongated in shape and with a flattened transversal cross section, this bag having further on its upper surface two longitudinal separable edges initially overlapping. The device comprises means for injecting (21) into the bag a hardening material and a shuttle (26) for moving along the bag, this shuttle being shaped in front for continuously moving apart said longitudinal edges from each other at least in a direction perpendicular to the plane of the bag and for defining a lateral opening extending along a set length to enable the insertion of the injecting means into the bag, the shuttle being further shaped at the rear for continuously bringing together said longitudinal edges so as to make them overlap and assemble them.

Description

l0l520253035CA 02264891 1999-03-05.I_,Dev’ m d ' ' o w’m ter' n ' r ' uThe present invention relates to a device forcovering a member of elongate shape, such as a cable ora pipeline laid on the seabed.American Patent US 4,480,943 discloses a devicefor covering a pipeline laid on the seabed, designed todeploy over the pipeline a bag of elongate shape whichin cross section has a flattened shape, and which isfilled with a curable material such as cement originat-the bag being filled byan injection member as it is deployed. The bag more oring from an accompanying ship,less matches the profile of the member covered beforethe material injected into it becomes cured. This thusprovides a protection, with a shape that is highlysuited to that of the member covered, againstmechanical attack, associated, for example, withmaritime traffic or with fishing. The bag can alsoserve to hold the covered member in place against theTheon theaction of underwater currents. bag has twohand, becontinuously parted to form an opening on the top ofthe bag,longitudinal edges which can, oneallowing the injection member to be inserted,and on the other hand, be joined together downstream ofthis member.The aforementioned American patent proposes toequip the longitudinal edges with a zip—type closure,deployment of theshaped at thewhich duringshuttlebag runs through afront laterally to part thelongitudinal edges and form the opening for the inser-tion of the injection member, and shaped at the back tobring the said longitudinal edges back together againand reseal the bag.This same prior-art American patent also pro-poses that the longitudinal edges of the bag be super-imposed downstream of the opening through which thel01520253035CA 02264891 1999-03-05-2-injection member is inserted, so that they can bejoined together by clipping.TheUS 4,480,943 is not entirely satisfactory,device described in American Patentand in par-/ ticular poses problems in terms of thel01520253035CA 02264891 1999-03-05_2a._reliability of thefor themeans used opening and resealing bagcontinuously.DE-A-31 44 092 describes an envelope which isfilled with a the‘in cross section, a flattered overall shape,curable material, said envelopehaving,the opposite walls of which are made of woven fabricThetechnique is of the pile-weaving type with two piecesand are connected by woven-in straps. weavingface to face, the length of the said straps, when taut,determining the thickness of the bag when filled.The invention aims to carry out the continuousfilling of the bag easily and reliably.The thisdevice for continuously filling with a curable materialinvention achieves by proposing aa bag of elongate shape which in cross section has aflattened shape, this bag also having on its upper facetwo separable longitudinal edges that initially over-lap, the device comprising an injection member allowinga curable material to be injected into the bag and ashuttle intended to be the thisshuttle being shaped at the front to continuously partmoved along bag,the said longitudinal edges from one another at leastin a direction perpendicular to the plane of the bagand to define a lateral opening extending over a givenlength to allow the injection member to be insertedinto the bag,the rear to continuously" bring the said longitudinaledges back together again to make them overlap and jointhem together.In. a specific embodiment of the said. device,the bag at the lateral end of the said longitudinaledges has guide ribs and the shuttle has an externalguide and an internal guide which have grooves shapedto guide the said ribs,thein their own plane,the external guide extendingupstrean1 of internal guide, the two guides eachextending which two planes arethe shuttle furthermore being shaped at‘l0l5CA 02264891 1999-03-05-3-parallel, and the separation between which correspondsmore or less to the distance between the said ribs whenthe longitudinal edges of the bag are joined togetherso as to reseal the bag, the said shuttle furthermoreComprising at the front a parting member that extendstheupstream of the internal guide in order to part thelaterally between said planes and is placedlongitudinal edges of the bag when the latter is run-ning through the shuttle, the shuttle comprising at thetheexternal guide for joining the said longitudinal edgesrear a presser member -situated downstream ofback together again.Thanks to the invention, the longitudinal edgesof the bag can be fitted with means of removablefastening of the Velcro strip type and the longitudinaledges of thel0l520253035CA 02264891 1999-03-05 stock of canremainingunfilled baginitially be joined together, with it still being pos-sible for them to be parted then joined back togetheragain in a particularly reliable way.A filling device of this kind furthermore makesit possible to avoid the means of removable fastening,thebeing subjected to shear forces liablewhich are preferably of Velcro strip type asindicated above,to damage them as they pass through the shuttle, in theevent that the longitudinal edges of the unfilled bagwere joined together with a certain lateral offset.Another subject of themethod of covering a member of elongate shape,invention is a novelsuch asa cable or a pipeline laid on the seabed, of the typein which a bag of elongate shape is deployed over theand of the typeis moved along the bag in order to fillmember to be covered, in which afilling devicethe bag with a curable material as the bag and the saidfilling device undergo relative movement, characterizedin that it comprises the step that consists in injec-‘ting the said curable material using an injection mem-ber into a quantity of the said curable material whichwas introduced into the bag beforehand and is stillfluid.Thus the curable material can be injected with-out contact with the water and a filler of metal rein-forcing elements can be added to the curable materialwithout these metalany need to fear problems ofelements becoming corroded by the water.l0l520253O35CA 02264891 1999-03-05-4-The presence of the metal elements appreciablyincreases the mechanical strength when the curablematerial has set and it becomes possible thanks to theinvention, for an equivalent mechanical strength, touse an appreciably smaller amount of curable materialthan was used in the prior art.Theachieved thanks to the invention makes it possible tosaving in curable material that can bereduce or even avoid resupplying the accompanying shipwith curable material, and this is particularly attrac-tive when the cable or pipeline is being covered in thehigh seas.In a specific embodiment of the method accor-ding to the invention, the said metal elements have anelongate shape and their length is between 2 and 3 cmand their cross section between 0.4 mm2 and 0.8 mm2.In a special embodiment of the method accordingtheinjection member is moved with respect to the bag into the invention, when a length of bag is full,order to withdraw it from the curable material con-tained in the bag and the bag is then sealed along atransverse sealing line, then the remaining stock ofunfilled bag is optionally detached from the filled andsealed length of bag.As a preference, the bag is sealed by clippingafter the injection member has been brought into aposition in which it does not impede the sealing of thebag.In a special embodiment of the method according‘to the invention; the bag has two main opposed wallsconnected by straps whose length when taut determinesthe thickness of the bag after filling. Advantageously,each main wall of the bag consists of a woven fabricand the said straps consist of filaments woven intothis fabric using a technique of the pile weaving typewith two pieces face to face.The inventors have quite surprisingly observedthat despite the use of reinforcing elements of elon-gate shape and the presence of the filaments liable, by101520253035CA 02264891 1999-03-05-5-a sifting action, to oppose a good distribution ofreinforcing elements, the reinforcing elements could bedistributed relatively uniformly within the bag duringfilling.A tentative explanation would lie in the factthe distribution ofthat elements isreinforcingimproved by the in—situ injection of curable material,the direction of flow into the bag out of the injectionmember having a not insignificant transverse component.Furthermore, although one might initially haveworried that gaps would be formed between the weftof the woven fabric where thefilaments connectingfilaments are joined when these filaments are taut,which gaps may have caused leaks of curable materialwhile it was still fluid, the inventors have observedthat this problem could be overcome thanks to a more orless uniform distribution of straps, in sufficient num-ber, and. that suckx a distribution of straps did. notoverly prevent a sufficient distribution of the metalreinforcing elements within the bag.In a special embodiment of the invention use ismade of the injection member for moving the straps awayfrom the said longitudinal edges.In this case, the injection member is advanta-geously shaped in such a way that where it enters thebag it forms a deflector capable of moving the strapsaway from the said longitudinal edges.It is thus avoid thepossible to strapsbecoming trapped between the longitudinal edges of the-bag when these edges are brought one against the otherto be joined back together again, something which wouldhave the effect of hampering the expansion of the bagduring filling and of reducing the strength of thejoint between the longitudinal edges.Thegeously shaped so that it at least partially deploysinjection member is furthermore advanta-the straps situated close to the region in which thecurable material is injected.10152O253035CA 02264891 1999-03-05-5-A further subject of the invention is a bag ofelongate shape capable of being used as an envelope forcasting a fluid material inside the bag with a view tothesaid bag in cross section having a flattened overallproducing a gmotecting member of elongate shape,shape, comprising opposed main walls consisting ofwoven fabric and connected by straps which are woveninto the said main walls using a technique of the pilethe lengthof the said straps when taut determining the thicknessof the bag when filled.A further subject of the invention is a pro-weaving type with two pieces face to face,tecting member of elongate shape consisting of a bag asaforementioned filled with a curable material, prefer-ably cement, and advantageously comprising a reinforc-ing filler consisting of metal elements.Other features and advantages of the presentinvention will become clear from reading the detaileddescription which will follow ofembodiment of the invention,one non—limitingand from examining theattached drawing in which;- Figure l is a diagrammatic perspective viewillustrating the use of a device according to theinvention,7 Figure 2 is a diagrammatic sectional View ofa member of elongate shape covered with a protectingbag in accordance with the invention,— Figure 3 is a diagrammatic sectional view ofa device in accordance with oneinvention, _— Figure 4 is a diagrammatic side View of theinjection member and of the shuttle,— Figure 5 is a diagrammatic plan view in thedirection of the arrow V of Figure 4,— Figure 6 is a diagrammatic side View depic-ting the shuttle,— Figure 7 is a diagrammatic front—on view inthe direction of the arrow VII of Figure 6,embodiment of the‘l01520253035CA 02264891 1999-03-05-7-- Figures 8 to 10 show various cross sectionsthrough the bag during filling,— Figure 11 is a diagrammatic view similar toFigure 3 showing the device once a length of bag hasbeen filled and before this length of bag is sealed andcut.Depicted diagrammatically and in perspective inFigure 1 is a cable 1 for conveying electrical powerlaid on the seabed and in the process of being coveredwith. a bag 2 deployed and filled continuously by atracked. vehicle 3 connected to an accompanying ship4 by a pipe 5 for supplying a curable material to beinjected into the bag,lifting cable 7.by a control cable 6, and by aOf course it would not be departing from thescope of the invention if the vehicle 3 would be usedto cover any other member of elongate shape such as apipeline for transporting hydrocarbons for example, orfor filling a bag of elongate shape.In the particular example described, the bag isdeployed over the member to be covered by the trackedvehicle 3.It would not be departing from the scope of theinvention if the bag in the unfilled state were firstof all to be laid,member to be covered,partially" or entirely; over thefor example while this member isbeing laid, and the tracked vehicle 3 then made totravel along the bag thus laid in order continuously tofill the bag as the vehicle moves along.In this case, the means for housing a reservestock of unfilled bag are replaced by means for guidingthe unfilled bag and bringing it into a suitable posi-tion for filling it.In thematerial is atherelativedescribed,theof which is between 1.6 and 2.4,1.8 and 2.1,forcing elements of elongate shape made of steel with aparticular examplecurable cement slurry,density preferablybetween containing a filler of metal rein-length of between 2 and 3 cm and a cross section ofl01520253035CA 02264891 1999-03-05-8-between 0.4 and 0.8 mmz, and which is contained in thecurable material in a proportion of the order of 20 to80 kg per m3 of curable material. For relative densitythe metal elements tend to settlethevalues of below 1.6,out in the bag, and for values higher than 2.4,slurry becomes difficult to inject.The vehicle 3 is self—propelled and is fitted,whichallow it to follow the member to be covered without thein the known way, with detectors, not depicted,intervention of divers.Because there are no divers, it is possible tolay the bag relatively easily and inexpensively even ona seabed in very deep water.The curable material is injected into the bagso that the bagcan mould itself to the profile of the member to beunder pressure while it is still fluid,covered, as illustrated in the cross section of Figure2.The bag 2 ii; of elongate shape, has a crosssection of a flattened overall shape and comprises twomain walls 8 and 9 which are joined at the lateral ends10 of the11 whose length when taut determines the thickness ofbag and connected in places by strapsthe material protecting the covered member.An elongate bag is understood to mean. a bagwhose length is at least ten times greater than itswidth.By way of indication, the width of the bag isfor example of the order of 2 m and its thickness is‘between 10 and <50 cm, and preferably between 15 and30 cm. The length of a length of bag may, for example,be as much as 500 m or even several kilometres.When the material filling it has cured, the bagconstitutes a protective barrier against externalmechanical attack and also against corrosion and maythe heat thecovered is a pipeline conveying hot hydrocarbons.furthermore reduce loss when memberWhen the bag 2 is deployed on the seabed, itrests via its lower wall 8 on the seabed and against101520253035CA 02264891 1999-03-05_ 9 _the cable 1. The upper wall 9 in its middle region com-overlapping andprises two longitudinal edges 1213 that can be joined together removably using contact-fasteners 14 and 15, of the Velcro strip type.The longitudinal edges 12 and 13 are equippedon their free borders with respective guide ribs 16 and17, which in the example described have a more or lesscircular cross section.Straps 11 are woven into the main walls 8 and9 by a sofcalled pile weaving technique with two piecesfacing each other which is in itself known and will notbe described in further detail.The location of the straps 11 is chosen to givethe filled bag a umre or less constant predeterminedon the length of thethe thebag preventing the good distribution ofthickness which depends saidstraps without howeverwithin thepresence of strapsmetal reinforcing elements added to the cement slurry.In the particular example described, the straps11 are distributed more or less in a staggered configu-ration with a spacing of 6 cm in the longitudinaldirection of the bag and a separation of 3 cm betweentwo rows of straps. There are no straps 11 between the12 and 13,this absence, from the point of View of the ability oflongitudinal edges and to compensate forthe bag mechanically to withstand the pressure of thecement slurry, the straps adjacent to the longitudinaledges 12 and 13 are doubled.Figure 3 schematically illustrates the deploy—'ment and the continuous filling of the bag 2.The"downstream"terms "front", "rear", "upstream" andare used in this description to refer tothe direction of travel of the bag with respect to thetracked vehicle 3; the ‘terms "front" and "upstream"thus relating to elements or parts of elements whichpoint towards that portion of the bag which isfilled and the termsnot"rear" and "downstream" relatingto elements or parts of elements which are situated onthe same side as the full part of the bag.l01520253035CA 02264891 1999-03-05.. _In the particular example described, the bag2 is stored on the vehicle 3 wound onto a reel18 situated at the front of the Vehicle, with thelongitudinal edges 12, 13 joined together.The reserve stock of bag stored on the reel18 is unwound continuously in a way that is coordinated_with the forward travel of the vehicle 3 and it passesover a guide table 19 which is inclined downward andtoward the rear of the vehicle as far as a short dis-tance away from the seabed, so that each filled portionof bag is laid gently over the member to be covered andonto the seabed.The vehicle 3 also comprises a clipping cutter20 for transversely sealing and detaching a filledlength of bag.The curable material is injected into the bagby means of an injection line 21 secured at the top toa support 22 capable of being moved along a guidestructure 23, the latter‘ being secured to the guidetable 19 and arranged above and parallel to it.The injection line 21 is connected at its upperhose 24 itself25 connected to the pipe 5.A shuttle 26 is designed, on the one hand, to12 and 13create an opening to allow the injection line 21 to beon the other hand, then towill beend to a connected to a fittingpart the longitudinal edges in order toinserted into the bag and,theexplained in greater detail later.join longitudinal edges together asThe shuttle 26 is secured to the aforementionedsupport 22 and as depicted more specifically in Figures4 to 7 comprises an external guide 27 and an internalguide 28 which has grooves shaped to guide the ribs 16and 17 respectively.Theconsidering the direction of travel of the bag over theguide table 19,external guide 27 is extended, whenupstream of the internal guide 28. Astheinternal guide 28 and external guide 27 each followcan more particularly be seen from Figures 5 and 7,l0152O253035CA 02264891 1999-03-05_ ll _paths with inflections in respective vertical planes,the corresponding more or less to theseparation of the ribs 16 and 17 theedges of the bag are joined together toseparationguide whenlongitudinalseal the bag.The shuttle 26 furthermore comprises a partingmember 29 the28 and having a front end 30 which is inserted betweensituated upstream of internalguidethe longitudinal edges 12 and 13 in order to part them13¢ a wedge effect, amd a presser member 31 situateddownstream of the external guide 27 and opposite a sole32 for edges 1213 back together again before they leave the shuttle26.plate joining the longitudinal andThe injection line 21 has a portion 33 exten-ding between the external guide 27 and the internalguide 28 and oriented along an axis I contained in aplane more or less parallel to the plane of the guidetable to thedirection of travel of the bag. The axis I is thus more19 and forming an angle of about 45°or less parallel to the plane of the bag travellingover the guide table 19.The portion 33 is connected to a straight por-tion 34 the axis J of which extends parallel to thedirection of movement of the bag over the guide tableand parallel to the latter.The portion 34 is connected, by an inflectionportion 35, ix: a Very long straight portion with anaxis K parallel to the aforementioned axis J and situ—‘ated more or less in the mid—plane of the bag when thelatter is travelling over the guide table 19. As anthe length of themeasured parallel to theindication, in the example described,portions 35 and 36 together,direction of travel of the bag, is as much as 1m80.A more detailed description of the way in whichthe shuttle 26 acts on the longitudinal edges 12 and13 will now be given with reference to Figures 8 to10 which show various cross sections through the bag,l0l52O253035I the portion 33 of the injection line,CA 02264891 1999-03-05-12..on the cutting lines VIII, IX and X of Figure 3,respectively.The bag 2 comes into contact with the shuttle26 with its walls 8 and 9 more or less one against theother and the and 13The fastening meanslongitudinal edges 12 joinedtogether as depicted in Figure 8.14 and 15 are protected from the outside thanks to thefact that they are joined together.theIn this way it ispossible to avoid Velcro strips losing theireffectiveness on account of soiling.That portion of the rib 17 that fits into theexternal guide 27 is thedeflected outwards whileparting member 29, with a pulling force in a verticalplane, parts the longitudinal edges 12 and 13 upstreamof the internal guide 28.A lateral opening is thus formed in the bag,through which opening the injection line 21 penetratesthe interior of the bag, from the side, as depicted inFigure 9. The axis I is more or less parallel to theplane of the longitudinal edges arranged face to faceon each side of the portion 33 of the injection line.theportion 33 of the injection line 21 advantageously con-As can be seen from examining Figure 9,stitutes a deflector‘ which. moves the straps 11 awayfrom the opening formed between the longitudinal edges12 and 13. It is thus possible to avoid the straps 11becoming sandwiched between the longitudinal edges 12and 13 when the longitudinal edges 12 and 13 are joinedback together again and thereafter impeding the‘expansion of the bag during filling with curablematerial.The internal guide 28 and the sole plate 32deflect the longitudinal edge 13 outwards downstream ofand bring it backtowards the longitudinal edge 12 so that the two longi-tudinal edges can be joined together by pressing bet-ween the presser member 31 and the sole plate 32.The bag in the process of being filled has beendepicted in Figure 10.l0l520253O35CA 02264891 1999-03-05-13-It may be seen from this figure that the straps11 are practically taut, their length determining themaximum thickness of the material with which the bag 2is filled.The speed at which the bag is unwound is chosento suit the flow rate of curable material injected andthe size of the bag so that the injection member iskept immersed in the curable material during filling.It is thus possible to avoid the metal rein-forcing elements coming into contact with seawater, asthis would, in the long term, cause them to corrode andreduce their effectiveness.Figure 11 depicts the vehicle 3 at the end ofthe operation of filling a length of bag 2, which hasto be and detached theremaining stock of undeployed bag wound onto the reell8.sealed transversely fromThe support 22 is moved upwards from the low-ered position it kept during the filling process, so asto bring the injection line 21 out of the curable mate-rial contained in the bag and above the clipping cutter20. Thus the injection line 21 does not hamper theclipping of the bag over its entire width, nor does ithamper the cutting operation.Of course the invention is not limited to theembodiment which has just been described.In particular, the vehicle 3 can be used not atsea but on land for continuously filling a bag like theaforementioned one with a material injected into it in‘the fluid state._Although the device according to the inventionis particularly suitable for filling a bag with a cur-able material containing a filler of metal reinforcingelements, it is possible,the invention, toto which fillersreinforcing elements may or may not be added.although the shuttle 26 of theembodiment just described is particularly suitable forwithout departing from thescope of use various fillingIor non—metalmaterials, of metalFurthermore,l0l52025CA 02264891 1999-03-05-14-parting the longitudinal edges of the bag then joiningthem back together again when these edges have fasten-ers of the velcro strip type, it would not be departingfrom the scope of the invention if the longitudinaledges were to be joined together using other fasteningthemethod of opening the bag and joining it back up bymeans, for example sewing, welding, or clipping,parting then bringing back together the longitudinaledges in a direction which is in a plane generally per-pendicular to the plane of the bag allowing accurateand reliable positioning of the longitudinal edges aswell as offering the possibility of inserting theinjection member into the bag from the side rather thanfrom above, therefore of using thedeflectorinjection membereasily as a for parting the straps, asexplained earlier.The remaining undeployed stock of bag may bestored on the vehicle 3, not wound onto a reel as des-cribed above, but folded concertina—style.The bag when full may have a thickness that isconstant along its length or varies, the variation inthickness easily being obtained by altering the lengthof the straps.It is thus possible, using just one bag, tocover a member of elongate shape with varying thick-nesses of material for example by altering the amountof overlap to suit a variation in size or type of mem-ber to be covered or to suit an environment the sever-ity of which changes.

Claims (22)

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1. Device for continuously filling with a curable material a bag (2) of elongate shape which in cross section has a flattened shape, this bag also having on its upper face two separable longitudinal edges that initially overlap, the device comprising a mobile injection member (21) allowing a curable material to be injected into the bag as it moves and a shuttle (26) intended to be moved along the bag, this shuttle being shaped at the front to continuously part the said longitudinal edges from one another at least in a direction perpendicular to the plane of the bag and define a lateral opening extending over a given length to allow the injection member to be inserted into the bag, the shuttle furthermore being shaped at the rear to continuously bring the said longitudinal edges back together again to make them overlap and join them together.

2. Device according to Claim 1, characterized in that it comprises sealing means (20) allowing a filled length of bag to be sealed off, and in that the said injection member is secured to a mobile support (22) so that it can be moved with respect to the said sealing means.

3. Device according to Claim 2, characterized in that the said shuttle (26) is secured to the said mobile support (22).

4. Device according to any one of Claims 1 to 3, characterized in that the said bag (2) comprises two main opposed walls (8, 9) connected by straps (11) which preferably consist of filaments whose length when taut determines the thickness of the filled bag.

5. Device according to Claim 4, characterized in that the said injection member (21) is shaped in such a way that where it enters the said bag it forms a deflector capable of moving the straps (11) away from the said longitudinal edges.

6. Device according to Claim 4 or 5, characterized in that the said injection member is shaped so that it at least partially deploys the straps (11) situated near to the region into which the curable material is injected.

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7. Device according to any one of Claims 1 to 6, characterized in that the said bag (2) at the lateral end of each longitudinal edge (12, 13) has a guide rib (16, 17), and in that the shuttle (26) has an external guide (27) and an internal guide (28) which have grooves shaped to guide the said ribs (16, 17), the external guide (27) extending upstream of the internal guide (28), the two guides (27, 28) each extending in their own plane, which two planes are parallel, and the separation between which corresponds more or less to the distance between the said ribs (16, 17) when the longitudinal edges (12, 13) of the bag are overlapping so as to close the bag, the said shuttle (26) further-more comprising at the front a parting member (29) that extends laterally between the said planes and is placed upstream of the internal guide in order to part the longitudinal edges of the said bag when the latter is running through the shuttle, and at the rear, a presser member (31) situated downstream of the external guide for joining the said longitudinal edges back together again.

8. Method of covering a member (1) of elongate shape, such as a cable or a pipeline laid on the sea-bed, of the type in which a bag (2) of elongate shape is deployed over the member to be covered, and of the type in which a filling device is moved along the bag in order to fill the bag with a curable material as the bag and the said-filling device undergo relative movement, characterized in that it comprises the step that consists in injecting the said curable material using an injection member (21) into a quantity of the said curable material which is already being introduced into the bag and is still fluid.

9. Method according to Claim 8, characterized in that a filler of metal reinforcing elements is injected together with the said curable material.

10. Method according to Claim 9, characterized in that the said metal elements have an elongate shape.

11. Method according to Claim 10, characterized in that the length of the said metal elements is between 2 and 3 cm and their cross section is between 0.4 and 0.8 mm2.

12. Method according to any one of Claims 9 to 11, characterized in that the proportion of the said filler in the curable material is of the order of 20 to 80 kg per m3 of curable material.

13. Method according to any one of Claims 8 to 12, characterized in that the said curable material is a cement slurry with a relative density of between 1.6 and 2.4.

14. Method according to any one of Claims 8 to 13, characterized in that the injection member is inserted into the bag via a lateral opening therein.

15. Method according to any one of Claims 8 to 14, characterized in that the said bag comprises two longitudinal edges (12, 13) equipped with means (14, 15) of removably fastening them one to the other, these means preferably being of the velcro strip type, the injection member being inserted through an opening formed between the said longitudinal edges that face each other, these edges being parted by pulling upstream of the said opening then joined together again by pressing downstream.

16. Method according to any one of Claims 8 to 15, characterized in that it comprises the step which, when a length of bag is full, consists in moving the injection member with respect to the bag in order to take it completely out of the curable material contained in the bag, in then sealing the bag along a transverse sealing line, then possibly in detaching the unfilled remaining stock of bag from the filled and sealed length of bag.

17. Method according to Claim 16, characterized in that the said bag is sealed by clipping.

18. Method according to any one of Claims 8 to 17, characterized in that the said bag has two main opposed walls (8, 9) connected by straps (11) whose length when taut determines the thickness of the bag after filling.

19. Method according to Claim 18, characterized in that each main wall (8; 9) of the said bag consists of a woven fabric and in that the said straps (11) consist of filaments woven into this fabric using a technique of the pile weaving type with two pieces face to face.

20. Method according to either of Claims 18 and 19, characterized in that use is made of the injection member (21) for locally deploying the straps (11) at the point where the curable material is injected into the bag.

21. Method according to any one of Claims 18 to 20, characterized in that use is made of the injection member (21) for moving the straps (11) away from the said longitudinal edges (12, 13).

22. Protecting member of elongate shape, of the type comprising a bag of elongate shape capable of being used as an envelope for casting a curable filler material such as cement inside the bag, the said bag in cross section having a flattened overall shape, comprising opposed main walls (8, 9) consisting of woven fabric and connected by straps (11) which are woven into the said main walls using a technique of the pile weaving type with two pieces face to face, the length of the said straps (11) when taut determining the thickness of the bag when filled, the said straps (11) adjacent to the said longitudinal edges being doubled, characterized in that the said curable material contains a reinforcing filler consisting of metal elements.