EP0441076A1 - Tubular metallic pile with means for the injection of grout nearby the pile wall - Google Patents

Abstract

The pile comprises a tubular injection pipe (17) connected via a plurality of non-return valves (18) to a plurality of injection orifices (16) traversing the wall, characterised in that at least one non-return valve (18) is mounted on the injection pipe (17) inside a transfer chamber (20) connected with the corresponding injection orifice (16). …<??>The invention is used in the field of anchoring piles for foundations on land, in rivers and/or at sea. …<IMAGE>…

Description

The present invention can be used in particular in the field of anchor piles driven into the ground. Such piles are integrated into pile foundations made on land, in rivers or at sea.

It is known to improve the anchoring capacity of metal tubular piles by sealing, after threshing, their walls to the ground using a cement grout. This sealing significantly increases the lateral friction of the pile with respect to the ground and consequently the resistance of the pile to the effects of compression and especially of traction. To do this, metallic tubular piles have already been proposed equipped with a device allowing the injection of grout in the vicinity of the wall of the tube forming the pile, of the type comprising an injection pipe connected through a plurality of check valves to a plurality of injection ports passing through the wall of the tube. In particular, a device described in patent FR 2,237,475 has non-return valves mounted in the same wall of the pile tube without real protection.

The object of the invention is to propose a metal tubular pile equipped with an injection device of simple and robust design, capable of being installed without particular difficulty as well on micropiles, piles of small diameter (for example 600 mm ) or large diameter piles (for example 2,500 mm).

More particularly, the invention proposes a metal tubular pile equipped with a device allowing the injection of grout in the vicinity of the wall of the tube forming the pile, of the type comprising a tubular injection pipe connected through a plurality of non-return valves to a plurality of injection orifices opening out in the vicinity of the wall of the tube and distributed along said tube, characterized in that at least one non-return valve is mounted on the injection line inside a transfer chamber communicating with at least one of said injection orifices.

It should be noted that the arrangement according to the invention of the non-return valves on the injection pipe itself makes it possible to limit the size of the openings made in the wall of the tube to that of the injection orifices proper and thus not to affect the resistance capacity of the tube. In addition, the non-return valves benefit from total protection by their position inside the transfer chambers. Finally, the rinsing of the valves after an injection operation is facilitated by the arrangement of the valves, thereby eliminating the risk of a cement plug forming at the inlet of the non-return valves.

According to a first embodiment of the invention, the non-return valves consist of cuffs of elastic material, for example of elastomer, threaded on the outside of the injection pipe with regard to perforations suitably distributed along of driving. Advantageously, the internal volume of the transfer chamber is lined with a filling material with elastic property and / or liable to fracture, for example polyurethane foam or wax.

According to another embodiment of the invention, the transfer chamber is provided with at least one injection orifice which does not pass through the wall of the tube.

According to yet another embodiment of the invention, the transfer chamber is delimited on at least one of its sides by a portion of the wall of the tube, said portion being provided with at least one injection orifice passing through the wall of the tube. Advantageously, the injection pipe is divided into sections each provided with a non-return valve, said transfer chambers being pre-assembled on said sections before final association with the wall of the tube of the tubular pile.

According to a first variant of a tubular pile in accordance with the invention, the transfer chamber is produced from a tubular element crossed by the corresponding section of the injection pipe, said tubular element being welded to the wall of the tube of the pile around the injection orifice passing through said wall, and closed at its other end by a closure plate optionally pierced with another injection orifice. Advantageously, the tubular element has at least one widened opening to allow the mounting of the injection pipe section provided with the non-return valve, said opening being closed by a connection sleeve disposed around said injection pipe. Optionally, the connection sleeve has an internal thread used for the assembly of two sections of the injection pipe. This first variant is particularly well suited to tubular piles of large diameter.

According to a second variant of a tubular pile according to the invention, the transfer chamber is produced from a cylindrical section of the pile tube, said section being of reduced axial extension and closed at its two ends by two plates circular sheet metal through which the corresponding section of the injection pipe passes. Advantageously, the pile tube is obtained by fixing, for example by welding, end to end of the transfer chambers with intermediate tubular elements. This second variant is particularly well suited to tubular piles of small diameter.

• la figure 1 montre une représentation schématique en coupe axiale longitudinale d'un premier mode de réalisation d'un pieu tubulaire selon l'invention ;
• la figure 2 montre une représentation partielle agrandie du pieu illustré à la figure 1 et dans laquelle une chambre de transfert est montrée en coupe selon le plan diamétral du pieu tubulaire passant par l'axe YY' de la conduite d'injection ;
• la figure 3 montre une représentation schématique en coupe axiale longitudinale d'un second mode de réalisation d'un pieu tubulaire selon l'invention et ;
• la figure 4 montre une représentation partielle agrandie du pieu illustré à la figure 3 et dans laquelle une chambre de transfert est montrée en coupe axiale.

Other advantages and characteristics of the invention will appear in the description below which refers to the accompanying drawings in which:

• Figure 1 shows a schematic representation in longitudinal axial section of a first embodiment of a tubular pile according to the invention;
• FIG. 2 shows an enlarged partial representation of the pile illustrated in FIG. 1 and in which a transfer chamber is shown in section along the diametrical plane of the tubular pile passing through the axis YY 'of the injection pipe;
• FIG. 3 shows a schematic representation in longitudinal axial section of a second embodiment of a tubular pile according to the invention and;
• Figure 4 shows an enlarged partial representation of the pile illustrated in Figure 3 and in which a transfer chamber is shown in axial section.

The metal tubular pile 10 according to the invention illustrated in longitudinal section in FIG. 1 comprises a tube 12 of resistant steel forming the very structure of the pile equipped with a device 14 mounted inside the pile and allowing the injection of cement grout (the section shown in Figure 1 being made along a diametrical plane of the tube 12 passing through its axis XX '). By way of nonlimiting example, the tube 12, open at the bottom, has a large diameter (between 1 and 2 meters) for a length greater than 30 meters. The tube 12 is pierced along a generatrix with several injection orifices 16 thus crossing the wall of the tube and intended for allow the flow of cement grout in the vicinity of the external face of the wall of the tube 12. These orifices 16 are regularly distributed along the tube at a spacing of several meters (in general between 3 and 5 meters) adapted to the characteristics of the stake sealing sought. Of course, without departing from the scope of the invention, a variant not shown of the pile illustrated in FIG. 1, presents several (for example 2, 3 or 4) injection devices similar to device 14, distributed regularly over the internal periphery of the circular section of the tube taken perpendicular to the longitudinal axis of the latter.

The injection device 14 comprises an injection pipe 17 produced from a metal tube with a diameter of the order of 60 mm and on which are mounted non-return valves 18 intended to prevent the backflow of grout of cement in the pipe 17. Each non-return valve is disposed inside a transfer chamber 20 communicating directly with one of the injection orifices 16 passing through the wall. The lower end, if we consider FIG. 1, of the pipe 17 closed by a plug 22 is protected, in particular during the beating of the pile, by a strong sheet shield 23 with conical head, welded to the tube 12. It should be noted that the situation of the non-return valves on the injection pipe itself makes it possible to reduce the diameter of the injection orifices 16 drilled through the wall of the tube 12 to what is strictly necessary for the injection. This characteristic is advantageous in terms of the mechanical strength of the equipped tube.

In variants not shown of the pile according to the invention, the injection pipe equipped with the transfer chambers is mounted outside the pile, the transfer chambers being provided with orifices not not crossing the wall of the tube (the grout is injected on the outside face of the wall of the tube) and / or of holes crossing the wall of the tube (the grout is injected on the inside face of the tube).

The enlarged partial view, illustrated in FIG. 2, of a portion of the tube 12 associated with a transfer chamber 20, makes it possible to appreciate the details of production and mounting of the various constituent elements of the injection device 14. More particularly , the section illustrated in Figure 2 is made along the common diametral plane between the tube 12 (along the axis XX ') and the pipe 17 (along the axis YY').

As illustrated in FIG. 2, the injection pipe 17 is produced by a plurality of sections 24, 26 each carrying a non-return valve 18 constituted by a sleeve of elastomeric material such as rubber, threaded outside the line 17 to cover one or more perforations 28 formed in line 17 substantially in line with the injection orifice 16. As illustrated in FIG. 2, the orifice 16 is flared towards the outside of the tube 12. Around the valve 18, and opposite the orifice 16, the transfer chamber 20 made of welded sheet metal elements is fixed to the wall of the tube 12. More specifically, the envelope of the transfer chamber 20 is constituted by a tubular element 30, arranged perpendicular to the axis YY 'and closed by a plate 32 welded at 33. The tubular element 30, of square, rectangular or circular, is traversed right through by the section 24 and has, at its lower part, an enlarged opening 34 allowing the mounting of the section 24 equipped with the non-return valve 18. The enlarged opening 34 is closed by a sleeve of connection 36 welded at 35 to the tubular element 30. The sleeve 36 is provided with an internal thread capable of receive on the one hand the threaded end of the section 24, on the other hand the threaded end of the following section 26 to carry out the assembly of the two sections of the pipe 17. The upper part of the tubular element 30 is welded in 37 in the section 24, while the end of this same sleeve 30 located opposite the orifice 16 is welded at 39 on the internal wall of the tube 12 around this orifice 16. It can be noted that all the welds are carried out, without particular difficulty, from outside the transfer chamber. In a practical manner, a first step is to pre-assemble the transfer chambers and to mount them on the pipe 17, then to weld the tubular sleeves 30 on the wall of the tube 12 in line with the orifices 16 previously drilled.

Furthermore, the interior of the chamber is lined with a filling material 40 with elastic property and / or liable to fracture, such as expandable polyurethane foam or wax. This lining prevents the entry of soil into the transfer chamber 20 during and after the pile driving. This compressible (or fracturable) lining 40 is liable, during the injection of cement grout under pressure, to contract (or fracture) to allow, on the one hand, the cuff 18 to disengage from the wall of the tube 24, on the other hand to the grout to flow towards the orifice 16, while avoiding the formation of a grout plug after the injection either by resumption of its initial volume in the case of a compressible lining, or by the reduced dimensions of the passage offered to the grout in the case of a fracturable lining. It is thus possible to repeat the injection operation through the orifice in question, if necessary. In addition, in the event of an unexpected formation of a resistant grout film, the internal volume of the transfer chamber is large enough to allow the grout, during a new injection, to make another passage in the filling material towards the corresponding injection orifice.

The placement in the ground of the pile according to the invention is conventionally carried out by driving the tube 12, for example by driving or vibro-driving. The grout injection is then carried out using a grout injection line (not shown) equipped with two shutters, for example of the inflatable type, and lowered into line 17 so as to pressurize a portion of the pipe 17 straddling the non-return valve 18 in communication with a determined orifice 16. The pressurization of this portion allows the flow of the grout through the perforation (s) 28, the valve 18 and the orifice 16 in order to seal the external wall of the tube 12 and improve the lateral friction of the latter relative to the surrounding land. Conventionally, the injection of grout is carried out from the base of the pile, through the first orifice, then progressively going up orifice by orifice. During the entire operation, the injection pressure and the volume of grout injected are controlled by any known means. At the end, the injection line is removed and the line cleaned with water. It should be noted in this regard that rinsing with water is carried out without difficulty in the devices according to the invention in the absence of specific connections between the non-return valves and the injection pipe (these connections are generally hardly accessible to the rinsing water stream and suitable for the formation of grout plugs).

Optionally, the plate 32 is pierced with an injection orifice 41 allowing the injection of grout along the internal face of the wall of the tube 12 in order to improve the lateral friction of the pile on the ground plug inside the tube. Thus, the invention therefore proposes inter alia a simple injection device which makes it possible, from a single non-return valve, to inject simultaneously on the external and internal faces of the wall of the tube 12.

It should be noted that the implementation of the invention allows, without difficulty, to practice successive injections at the same level of ground (the corresponding orifice 16 always remaining freely accessible) and even to modify the types of grout used ( for example with the use of chemical grouts and silica gels or synthetic consolidating agents, in particular resins).

In the second embodiment of a metal tubular pile 50 according to the invention illustrated diagrammatically in longitudinal section in FIG. 3, the resistant steel tube 52, forming the very structure of the pile, is produced by the butt joint end, along the axis ZZ 'of the tube, transfer chambers 54 (54a to 54d) with tubular intermediate elements 56 (56a to 56d) with a length of between 3 and 5 meters.

In order not to overload the numbering, certain elements illustrated in FIG. 3 in a multiple manner, for example the transfer chambers, have been indexed from "a" to "d" from the base of the tube 52. This indexing will however not be used as necessary in the following description.

The tube 52 can optionally be closed at the bottom by a shoe 58. The injection pipe 60, itself made up of sections 62 (62a to 62c) assembled by threaded connections (64a to 64c), is arranged coaxially relative to the tube 52. The injection pipe 60 is closed at the bottom by a plug 66, a sufficient distance being provided between the plug 66 and the first transfer chamber 54a to allow complete descent into the pipe 60 from the shutter lower of the injection line (not shown). Furthermore, each transfer chamber contains a non-return valve 68 (68a to 68d) mounted on the injection pipe 60.

As illustrated in FIG. 4, a section 62 of the pipe 60 carries the rubber cuff 68 constituting the non-return valve threaded on the outside of this section 62. The cuff 68 covers one or more perforations 70 formed in the section 62 in line with injection orifices 72 passing through the wall of the tube 52 and arranged symmetrically with respect to the axis ZZ '(in the present case, the two orifices 72 are diametrically opposite).

The transfer chamber 54 is made of welded sheets from a cylindrical section 74 of the wall of the tube 52. The section 74 of limited axial extension (of the order of a few decimeters) is closed (after the installation of the sleeve 68) by two circular sheet metal plates 76 and 78 welded at 80 and 82 at their peripheries, as illustrated in FIG. 4. The plates 76 and 78, provided with central openings, are crossed by the section 62 and welded on this one at 84 and 86. Finally, the plates 76 and 78 are welded at their peripheries to the two adjacent tubular elements 56 (for example 56a and 56b) at 88 and 90 as illustrated in FIG. 4. Furthermore, the interior volume of the chamber 54 is lined with a filling material 92 with elastic property and / or liable to fracture such as expandable polyurethane foam or wax.

It should be noted that the tubular elements 56 and the edges 74 have identical dimensions in diameter and thickness and are obtained from the same grade of steel to guarantee substantially identical resistance characteristics along the tube 52 forming the stake structure.

The assembly of the pile 50 is carried out as follows. Firstly, each section 62 is fitted with a rubber sleeve 68 and a transfer chamber 54. After having closed, by the plug 66, the first section 62a thus equipped, the plate is welded. bottom of the chamber 54a with a first tubular element 56a, itself closed by the shoe 58. The threaded connection 64a is then mounted on the free end of the section 62a. Then, the other bottom plate of the chamber 54a is welded with the tubular element 56b. The operation is repeated in identical sequences for the other constituent elements of the tube according to an assembly order identified in FIG. 3 by the indexing a, b, c, d ...., each new sequence starting with the screwing of the new pipe section 62 on the fitting 64 already mounted on the previous section.

It should be noted that the equipped pile illustrated in FIGS. 3 and 4 is of simple and robust structure presenting no particular difficulty during its assembly. Furthermore, the same transfer chamber is capable of supplying, from a single non-return valve, several orifices located at a determined level of the pile and distributed around its periphery.

The establishment and sealing of the pile 50 is carried out in a similar manner to that already described for the pile 10 and will not be described again in detail. Depending on the type of pile driver used to drive the pile, it may it may be necessary to slightly shorten the last section (upper section) of the injection pipe compared to the last tubular element.

The invention is not limited to non-return valves of the rubber cuff type, but also includes the use of any other type of non-return valves located on the injection pipe (not shown), for example valves. constituted by split collars mounted on the outside of the pipe in line with the perforations allowing the passage of the grout, or valves constituted by slots with deformable lips made through the wall of the injection pipe.

Claims (15)

Tubular metal pile equipped with a device allowing the injection of grout in the vicinity of the wall of the tube (12, 52) forming the pile, of the type comprising a tubular injection pipe (17, 60) connected through a plurality of non-return valves (18, 68) to a plurality of injection orifices (16, 41, 72) opening out in the vicinity of the wall of the tube and distributed along said tube, characterized in that at least one valve non-return valve (18, 68) is mounted on the injection pipe (17, 60) inside a transfer chamber (20, 54) communicating with at least one of said injection orifices (16, 41 , 72). Metal tubular pile according to claim 1, characterized in that the non-return valves consist of sleeves (18, 68) of elastic material, for example elastomer, threaded on the outside of the injection pipe (17 , 60) with regard to perforations (28, 70) suitably distributed along said injection pipe. Metallic tubular pile according to claim 1, characterized in that the non-return valves consist of split collars mounted on the outside of the injection pipe (17, 60) facing suitably distributed perforations (28, 70) along said injection line. Metallic tubular pile according to claim 1, characterized in that the non-return valves consist of slots of deformable lips formed through the wall of the injection pipe. Metal tubular pile according to one of the preceding claims, characterized in that the internal volume of the transfer chamber (20, 54) is lined with a filling material (40, 92) with elastic property and / or capable of becoming fracture, for example polyurethane foam or wax. Metallic tubular pile according to one of the preceding claims, characterized in that said transfer chambers (20, 54) are made of sheet metal elements, for example welded tubes and / or plates. Metallic tubular pile according to one of the preceding claims, characterized in that the transfer chamber (20) is provided with at least one injection orifice (41) which does not pass through the wall of the tube (12). Metal tubular pile according to one of claims 1 to 6, characterized in that the transfer chamber (20, 54) is delimited on at least one of its sides by a portion of the wall of the tube (12, 74), said portion (12, 74) being provided with at least one injection orifice (16, 72) passing through the wall of the tube. Tubular metal pile according to claim 8, characterized in that the injection pipe (17, 62) is divided into sections (24-26, 62a / b / c / d) each provided with a non-return valve (18 , 68), said transfer chambers (20, 54) being pre-assembled on said sections (24-26, 62a / b / c / d) before final association with the wall of the tube (12, 52) of the tubular pile. Tubular metal pile according to one of Claims 8 and 9, characterized in that the transfer chamber (20) is produced from an element tubular (30) traversed by the corresponding section (24) of the injection pipe (17), said tubular element (30) being welded at one end to the wall of the tube (12) of the pile around the orifice injection (16) passing through said wall of the tube (12) and closed at its other end by a closure plate (32), said plate (32) being optionally pierced with another injection orifice (41). Metal tubular pile according to claim 10, characterized in that the tubular element (30) has at least one enlarged opening (34) to allow the mounting of the section (24) of injection pipe provided with the non-return valve ( 18), said opening (34) being closed by a connection sleeve (36) disposed around said injection pipe. Tubular metal pile according to claim 11, characterized in that the connection sleeve (36) has an internal thread used for the assembly of two sections (24, 26) of the injection pipe. Metallic tubular pile according to one of claims 1 to 6, characterized in that the transfer chamber (54) is produced from a cylindrical section (74) of the tube (52) of the pile, said section (74) being axial extension reduced and closed at its two ends by two plates (76, 78) of circular sheet metal through which the corresponding section (62) of the injection pipe (60). Metallic tubular pile according to claim 13, characterized in that the pile tube (52) is obtained by fixing, for example by butt welding, the transfer chambers (54a / b / c / d) with tubular elements intermediaries (56a / b / c / d). Metallic tubular pile according to one of the preceding claims, dark and sealed in the ground by injection of a cement grout in the vicinity of the wall of the tube forming said pile.

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