Plug for sealing a borehole with a tie rod or anchor nail, sealing kit including such a plug and method for sealing a borehole using such a kit

Abstract

Plug for a borehole with a tie rod or anchor nail, plugging kit comprising such a plug, and method for plugging a borehole using such a kit. The invention relates to a plug for a through-anchor borehole (10) formed in a wall (12) of a structure between a proximal end (14) and a distal end (16), said borehole (10) being equipped with a tie rod or anchor nail comprising a cylindrical anchor bar (20) extending into said borehole (10), said plug comprising: a central recess (32) of a diameter substantially equal to or slightly smaller than the diameter of said anchor bar so that said plug can be fitted onto said anchor bar and slid, under the action of a thrust force, into said borehole from said distal end proximal (14) towards said distal end (16) until an obturation position;a flexible rim (34) with a diameter greater than the diameter of said borehole so that said plug can be moved within said borehole and held in place by friction at said plugging position, when said thrust force ceases to be exerted. Figure for the abbreviation: Figure 3;

Description

Title of the invention: Plug for sealing a borehole with a tie rod or anchor nail, sealing kit comprising such a plug, and method for sealing a borehole using such a kit Technical field of the invention

[0001] The field of the invention is that of drilling, in particular drilling for anchor bolts. The invention relates more particularly to a borehole plug, in particular a borehole for an anchor bolt or nail, a plugging kit comprising such a plugging device, and a method for plugging a borehole, in particular an anchor borehole, implementing a kit according to the invention. Technological background

[0002] A tieback or anchor bolt is a mechanical device configured to transmit the tensile forces applied to it to a resistant layer of soil. An anchor bolt thus makes it possible to mechanically tie a wall of an engineering structure, such as a bridge abutment or retaining wall, to the surrounding ground.

[0003] An anchor tie generally comprises an anchor bar, an anchor head which transmits the tensile forces of the anchor bar to the structure to be anchored via a support system, a sealed part formed by a portion of the anchor bar on which the tensile force is transmitted to the surrounding ground via a sealing grout, and a free part formed by the portion of the anchor bar between the anchor head and the beginning of the sealing.

[0004] The installation of an anchor bolt generally comprises the following steps. In the first step, a borehole is drilled into the structure to be anchored using tools adapted to the surrounding terrain. This borehole can extend over several meters, depending on the structure to be anchored. In the second step, the anchor bar is inserted into the borehole until it extends into the ground behind the structure to be anchored. In the third step, the anchor bar is partially sealed, starting from the end of the borehole furthest from the structure to be anchored, with a cement grout to form the sealed portion of the anchor bolt. It is also possible to reverse the second and third steps, depending on the grout used and the nature of the soil.

[0005] Once the anchor bolt is in place, there is therefore a sealed portion in the surrounding resistant ground, and a free portion extending into the borehole between the The anchor bolt consists of a sealed section and an anchor head, the latter including a bearing on the anchored structure. This allows the anchor bolt to transmit the tensile forces applied to it to the surrounding resisting ground.

[0006] In some cases, it is necessary to fill the borehole made in the structure in order not to weaken it. This is the case, for example, for the abutments of old bridges.

[0007] When a borehole is large, it is practically complicated and uneconomical to fill the entire borehole. This filling is generally done by pouring a cement grout that must be fluid enough to flow through the borehole. This grouting can be done either by simple gravity, when the borehole has a sufficient incline, or under pressure.

[0008] Since the anchor bolt has a free portion, the cement grout will first fill the free portion before filling the portion of the borehole drilled into the structure. However, filling the free portion of the anchor bolt is pointless and generates unnecessary consumption of cement grout, resulting in an additional cost compared to the objective, which is solely to fill the borehole drilled into the structure.

[0009] In the case of an anchor nail, the entire borehole should be filled until the grout overflows from the borehole. However, some soils have voids or gaps such that the cement grout drains into the ground, without ever reaching the end of the structure to be anchored.

[0010] In other words, the solutions currently implemented on construction sites generate waste of cement and an additional cost of operations compared to the objectives pursued.

[0011] There is therefore a need for a solution to overcome these drawbacks. Objectives of the invention

[0012] The invention aims to provide a method for sealing a borehole, in particular an anchor borehole, which overcomes the disadvantages of the solutions currently implemented on construction sites.

[0013] The invention aims in particular to provide a plug for sealing an anchor borehole made in a wall of an engineering structure.

[0014] The invention aims in particular to provide such a plug which can be easily handled by an operator and arranged without difficulty in the borehole at the level of the desired sealing area.

[0015] The invention also aims to provide, in at least one embodiment, such a stopper that is economical to manufacture.

[0016] The invention also aims to provide a plugging kit for an anchor borehole comprising a plugging plug according to the invention.

[0017]

[0018]

[0019]

[0020]

[0021] Description of the invention To this end, the invention relates to a plug for sealing a through-bore anchor borehole formed in a wall of an engineering structure between a proximal end and a distal end and extending to a resistant ground arranged at a distance from said wall, said borehole being equipped with a tie rod or anchor nail comprising a cylindrical anchor bar extending in said borehole between said proximal end and a portion sealed in said resistant ground, said plug comprising: - a central recess of diameter substantially equal to or slightly less than the diameter of said anchor bar so that said plug can be fitted onto said anchor bar and slid, under the action of a thrust force, in said borehole around said anchor bar from said proximal end to said distal end to a sealing position, - a flexible perimeter with a diameter greater than the diameter of said borehole so that said plug can be moved in said borehole and held in place by friction at said plugging position, when said thrust force ceases to be exerted. The obturation plug according to the invention can therefore be moved in the borehole between the proximal end and an obturation position, which will preferably be chosen in the vicinity of the distal end of the wall. The diameter of the central recess is substantially equal to or slightly less than the diameter of the anchor bar, which means, in the context of the invention, that the diameter is equal to or less than 5% less than the diameter of the anchor bar. Preferably, the diameter of the recess is slightly less than the diameter of the anchor bar such that the plug can be held by friction on the anchor bar, but still allow the plug to slide along the anchor bar if a force greater than the friction is applied by an operator. The plug's circumference is flexible and has a diameter larger than the borehole diameter, allowing the plug to be moved within the borehole and held in place by friction against the borehole when the force for displacement is released. The plug's circumference diameter is, for example, 5% larger than the borehole diameter. Of course, a different ratio between the circumference diameter and the borehole diameter can be used depending on the borehole conditions and the plug material. A plug according to the invention thus makes it possible to seal a borehole at a sealing position so that a filling material, such as cement grout, can then be poured into the borehole. This grout, poured from the end Proximal, it can flow down the borehole to the sealing plug, which then blocks its flow. This eliminates the risk of grout flowing into the resistant soil behind the wall. This cement grout then fills the borehole in the wall, thus consolidating it.

[0022] Advantageously, the sealing plug according to the invention is formed of a disc made of an elastic material, such as rubber, pierced in its center to form said central recess and whose periphery forms said flexible surround.

[0023] According to this advantageous embodiment, the plug is formed of a disc made of an elastic material, that is, a material that can return to its original shape after being deformed, for example, when the applied stress is removed. Preferably, the disc is made of rubber. Thus, the rim of the rubber disc is flexible and can deform when the disc is moved within the borehole between the proximal end and the plugging position. Since the diameter of the disc is slightly larger than the borehole diameter, the rim of the disc is held in the deformed state, in the plugging position, and exerts a frictional force on the borehole wall.

[0024] Advantageously and according to this variant, said disc further comprises a plurality of radial cutouts extending from said periphery of the disc towards said central recess, without opening into said central recess, so as to form tabs which can bend during the movement of the disc in said bore, from said proximal end to said obturation position.

[0025] A disc according to this embodiment facilitates the movement of the disc within the borehole from the proximal end to the obturation position. In particular, the radial tabs can bend during the movement of the disc within the borehole. This makes it easier to overcome any obstacles, asperities, or constrictions along the borehole when moving the obturation plug from the proximal end to the obturation position.

[0026] According to an advantageous embodiment, the disc comprises at least four radial tabs, preferably eight radial tabs.

[0027] Advantageously and according to the invention, the diameter of said flexible perimeter has a diameter greater than the diameter of said borehole by less than 10%, preferably greater by 1 to 5%.

[0028] According to this embodiment, the diameter of the flexible rim is larger than the borehole diameter so that the plug can be self-held in the borehole and not move when the grout is poured into the borehole, without, however, being too large relative to the borehole to allow it to move within the borehole during plug placement. In other words, this diameter ratio is a good compromise between the need for the plug to be self-held by friction in the borehole and the need to be able to be moved within the borehole during its installation.

[0029] According to another variant of the invention, the sealing plug is formed of a toroidal inflatable pouch such that the center of the pouch forms said central recess and the periphery of the pouch forms said flexible perimeter.

[0030] Thus, according to this variant, a toroidal inflatable bag is used as a sealing plug. The bag is preferably inflated before insertion and movement in the borehole. This bag may, for example, include an inflation valve.

[0031] The invention also relates to a plugging kit for a through-bore anchor borehole formed in a wall of a structure between a proximal end and a distal end and extending to a resistive layer arranged at a distance from said wall, said borehole being equipped with a tie rod or anchor nail comprising a cylindrical anchor bar extending in said borehole between said proximal end and a portion sealed in said resistive layer, said plugging kit comprising: - a plugging plug according to the invention, - a hollow pusher tube for said plugging plug having: • a length greater than the length of said borehole within said wall, • an internal diameter greater than the diameter of said anchor bar and an external diameter less than the diameter of said borehole so that said tube can be slid on said anchor bar inside the borehole by an operator to exert said thrust force on said plug and move it inside said borehole between the proximal end and said plugging position.

[0032] A plugging kit according to the invention is therefore formed by the combination of a plugging plug according to the invention and a hollow pusher tube allowing an operator to move the plugging plug in the borehole between the proximal end and the plugging position, preferably chosen by the operator in the vicinity of the distal end.

[0033] The hollow tube is characterized by having a length greater than (or at least equal to) the length of the borehole within the wall, allowing the plug to be moved as close as possible to the distal end of the wall. It is also characterized by having an internal diameter greater than the diameter of the anchor bar, enabling it to be fitted onto the anchor bar and bear against the plug, so that an operator can maneuver the pusher tube and exert a pushing force on the plug to move it within the borehole. Finally, the hollow tube is characterized by having an external diameter smaller than the borehole diameter, allowing it to slide within the borehole. time that the sealing cap during the operation of the tube by the operator.

[0034] Advantageously, a plugging kit according to the invention comprises a plurality of plugging plugs according to the invention so as to be able to successively house said plurality of plugs in said borehole to increase the retention power of the filling grout.

[0035] According to this advantageous variant, the various sealing plugs of the kit can be slid successively into the borehole to improve the retention of the filling grout (pressure resistance) and / or to obtain sufficient sealing.

[0036] The invention also relates to a method of plugging an anchor borehole, using a plugging kit according to the invention, said borehole being through, formed in a wall of an engineering structure between a proximal end and a distal end and extending to a resistant ground arranged at a distance from said wall, said borehole being equipped with a tie rod or anchor nail comprising a cylindrical anchor bar extending in said borehole between said proximal end and a portion sealed in said resistant ground.

[0037] The sealing process according to the invention is characterized in that it comprises the steps of: - to fit said sealing plug onto said anchor bar, upstream of said borehole, - to fit said pusher tube onto said anchor bar until it comes to a stop against said sealing plug, - to exert a thrust force on said pusher tube so as to move the plug in said borehole between said proximal end and a plugging position, - remove the pusher tube once the sealing plug is in place in the said borehole, - to set up formwork at the proximal end, - to pour a filling grout into said borehole up to the limit of disgorgement of said borehole delimited by said formwork.

[0038] The advantages and technical effects of a sealing plug according to the invention and of a sealing kit according to the invention apply mutatis mutandis to a sealing process according to the invention.

[0039] The invention also relates to a sealing plug, a sealing kit and a sealing method, characterized in combination by all or part of the characteristics mentioned above or below. List of figures

[0040] Other objects, features and advantages of the invention will become apparent from the following description, given by way of non-limiting example only, and which refers to the attached figures in which:

[0041] [Fig.1] is a schematic cross-sectional view of a through-anchor bore formed in a wall of an engineering structure equipped with an anchor bolt,

[0042] [Fig.2] is a schematic view of a plug for sealing an anchor borehole according to one embodiment of the invention,

[0043] [Fig.3] is a schematic cross-sectional view of a plugging kit for an anchor borehole according to one embodiment of the invention,

[0044] [Fig.4a], [Fig.4b], [Fig.4c], [Fig.4d] are cross-sectional views illustrating the different steps of a sealing process according to an embodiment of the invention.

[0045] Detailed description of an embodiment of the invention

[0046] In the figures, the scales and proportions are not strictly to scale for illustrative and clarity purposes. Throughout the detailed description that follows with reference to the figures, unless otherwise indicated, each element of the plugging device according to the invention is described as it is arranged when the plug is housed in an anchor borehole, and each element of the plugging kit according to the invention is described as it is arranged when the kit is in use within an anchor borehole. This configuration is notably shown in Figures 3 and 4.

[0047] In addition, identical, similar or analogous elements are designated by the same references in all figures.

[0048] Figure 1 schematically illustrates a wall 12 of a structure equipped with an anchor tie rod comprising an anchor bar 20, the tie rod being intended to form a mechanical connection between the wall 12 and a resisting layer 100 arranged behind the wall 12. A through borehole 10 is made in the wall 12 and extends between a proximal end 14 and a distal end 16. The anchor bar 20 is housed in the borehole 10 and extends from an anchor head 18 arranged upstream of the proximal end 14 to a portion sealed 22 in the resisting layer 100 arranged behind the wall 12. The anchor head 18 secures the anchor bar 20 to the wall 12.

[0049] The invention aims to enable the reinforcement of the wall 12 by filling the borehole 10 formed in the wall 12. To this end, the invention provides for the use of a plug (one embodiment of which is shown in [Fig. 2]) configured to be able to be moved within the borehole 10, before mounting the anchor head 18, to a sealing position arranged near the distal end 16 of the borehole. Note that [Fig. 1] illustrates an anchor borehole without the plug according to the invention. [Fig. 3] illustrates the borehole with the plug according to the invention.

[0050] According to an embodiment shown in [Fig. 2], the sealing plug is formed of a rubber disc 30. Of course, nothing prevents the use of a disc made of a material other than rubber, provided that the material has elastic properties that allow it to self-hold in the borehole, as explained later.

[0051] The disc 30 has a central cylindrical recess 32 having a diameter d4 equal to or slightly less than the diameter d3 of the anchor bar 20 so that it can be mounted slightly by force on the anchor bar 20, while allowing it to slide on the bar 20 when a thrust force is exerted on the disc 30 (as shown in Figures 4a and 4b).

[0052] This disc 30 also has a plurality of radial cutouts 36, each extending from the periphery of the disc 34 towards the central recess 32, without opening into the central recess 32. These radial cutouts 36 thus form, in pairs, tabs 38 that can bend during the movement of the disc in the borehole 10 and hold the disc 30 in place in the borehole 10 when the thrust force ceases to be exerted, thus ensuring the self-holding of the disc in the borehole. To achieve this, the diameter d5 of the disc is slightly larger than the diameter dl of the borehole.

[0053] According to another embodiment not shown in the figures, the sealing plug is formed of a toroidal inflatable pouch whose center of the pouch forms the central recess and whose periphery of the pouch forms the flexible perimeter intended to come into contact with the internal wall of the borehole.

[0054] It should also be noted that an alternative could be to use an expanding foam placed directly in the borehole at the intended sealing position. This foam could, for example, be injected into the borehole using a cannula.

[0055] Fig. 3 schematically illustrates the anchoring kit according to an embodiment comprising the sealing plug 30 according to Fig. 2 and a pusher tube 40 intended to allow the installation of the plug in the borehole at the targeted sealing position.

[0056] Thus, the kit includes, in addition to the sealing plug already described, a hollow pusher tube 40 having a length greater than the length of the borehole, a diameter d2 greater than the diameter d3 of the anchor bar 20 and less than the internal diameter dl of the borehole 10. This tube can be formed in any type of rigid material.

[0057] Thus, the pusher tube 40 can be fitted onto the anchor bar 20 inside the borehole 10 by an operator to exert a pushing force on the plug 30 and move it inside the borehole 10 between the proximal end 14 and the plugging position. This plugging position is in practice located near the distal end of the borehole 10 of the wall 12, as shown in particular in [Fig. 3].

[0058] The different diameters of the parts involved must be chosen in such a way that the following relationship is respected: d5 dl d2 d3 d4.

[0059] Figures 4a, 4b, 4c and 4d schematically illustrate the different steps implemented by an operator to install the anchor plug in the borehole and to seal the borehole.

[0060] Thus, in a first step, the sealing plug formed from the disc 30 according to the embodiment shown in the figures, is fitted and slightly forced onto the anchor bar 20.

[0061] In a second step, schematically represented in [Fig.4a], the pusher tube 40 is fitted onto the anchor bar 20 until it comes to rest against the disc 30 fitted onto the anchor bar 20 in such a way that an operator can exert a pushing force on the disc 30. This pushing force is represented in [Fig.4a] by the arrows on either side of the tube 40.

[0062] In a subsequent step, schematically illustrated in [Fig. 4b], the disc reached its obturation position due to the pushing force exerted by an operator (represented by the arrows on either side of the tube 40 in [Fig. 4b]). The disc 30 was thus moved between Figures 4a and 4b, from the proximal end 14 of the borehole 10 to an obturation position located near the distal end 16 of the borehole 10. The elastic structure of the disc 30 allows its movement within the borehole, and the radial tabs bend to conform to the inner wall of the borehole.

[0063] In the next step, once the disc is positioned at the chosen sealing location, and as schematically illustrated in [Fig. 4c], the pusher tube 40 is withdrawn from the borehole 10 by the operator. The disc 30 is held in position by the elastic nature of the radial tabs, which exert a frictional force on the inner wall of the borehole.

[0064] Once the pusher tube 40 has been removed from the borehole, the next step, schematically illustrated by [Fig.4d], consists of pouring a filling grout 42 into the borehole 10 to fill the borehole and reinforce the wall structure 12. This grout flows, in the embodiment of the figures, by natural gravity in the borehole, until it comes against the sealing plug 30. The borehole 10 fills until the grout reaches the proximal end of the borehole.

[0065] Prior to the concrete pouring step, the process may include a step of setting up a temporary formwork 44 allowing on the one hand to pour the concrete up to the proximal end of the borehole, preventing it from overflowing from the borehole, and on the other hand to form a flat bearing surface at the proximal end to fix the anchor head.

[0066] Once the grout has set, or directly after grouting, depending on the characteristics of the cement used, the anchor head 18 can be mounted on the anchor bar to complete the anchoring. Filling the borehole thus improves the bearing surface of the anchor head on the wall, and may even reduce the dimensions of the anchor head since it is supported on a solid surface and not on a partially empty surface (the unfilled borehole).

[0067] The invention is therefore a simple but innovative solution for reinforcing the anchor boreholes made in the walls.

[0068] It should be noted that a variant of the invention can also be used for a borehole without anchor bolts by using an anchor plug without a central recess. Thus, the anchor plug without a central recess can be housed in the borehole, moved within the borehole until it reaches a sealing position, and grout can be poured into the borehole. To ensure the movement of the plug within the borehole, a tube can be used, but this tube need not be hollow since the anchor bolt is no longer present in the borehole.

Claims

Claims

1. A plug (30) for sealing a through-anchor borehole (10) formed in a wall (12) of a structure between a proximal end (14) and a distal end (16) and extending to a resistant ground (100) arranged at a distance from said wall (12), said borehole (10) being equipped with an anchoring tie rod or nail comprising a cylindrical anchoring bar (20) extending in said borehole (10) between said proximal end (14) and a sealed portion (22) in said resistant ground (100), said plug comprising a disc made of an elastic material, such as rubber, said disc further comprising: • a central recess (32) formed in the centre of the disc with a diameter substantially equal to or slightly smaller than the diameter of said anchoring bar (20) so that said plug can be fitted onto said anchoring bar (20) and slid, under the action of a pushing force,in said borehole (10) around said anchor bar from said proximal end (14) towards said distal end (16) to a closure position, • a flexible rim (34) at the periphery of the disc with a diameter greater than the diameter of said borehole (10) so that said plug can be moved in said borehole (10) and held in place by friction at said closure position, when said thrust force ceases to be exerted, said plug being characterized in that said disc further comprises a plurality of radial cutouts (36) extending from said periphery of the disc towards said central recess, without opening into said central recess, so as to form tabs (38) which can bend when the disc is moved in said borehole (10), from said proximal end (14) to said closure position.,

2. Stopper according to claim 1, characterized in that it comprises at least four radial tabs (38), preferably eight radial tabs.

3. Stopper according to one of claims 1 to 2, characterized in that said diameter of said flexible circumference (d5) has a diameter greater than the diameter of said drilling (dJ) by less than 10%, preferably greater by 1 to 5%.

4. Stopper according to claim 1, characterized in that it is formed from an inflatable toric pocket so that the center of the pocket forms said central recess and the periphery of the pocket forms said flexible perimeter.

5. Kit for sealing a through-anchor borehole (10) formed in a wall (12) of a structure between a proximal end (14) and a distal end (16) and extending to a resistant ground (100) arranged at a distance from said wall, said borehole (10) being equipped with an anchoring tie rod or nail comprising a cylindrical anchor bar (20) extending in said borehole between said proximal end (14) and a sealed portion (22) in said resistant ground (100), said sealing kit comprising: • at least one sealing plug (30) according to one of claims 1 to 4, • a hollow pusher tube (40) of said sealing plug having: • a length greater than the length of said borehole within said wall,• an internal diameter (d2) greater than the diameter (d3) of said anchor bar and an external diameter less than the diameter of said borehole (10) so that said tube (40) can be slid onto said anchor bar (20) inside the borehole (10) by an operator to exert said thrust force on said sealing plug and move it inside said borehole between the proximal end (14) and said sealing position.,

6. Sealing kit according to claim 5, characterized in that it comprises a plurality of sealing plugs according to one of claims 1 to 4, so as to be able to successively house said plurality of plugs in said borehole to increase the retention power of the filling grout.

7. Method for sealing an anchor borehole, using a kit sealing according to one of claims 5 or 6, said borehole (10) being through, formed in a wall (12) of a structure between a proximal end (14) and a distal end (16) and extending to a resistant ground (100) arranged at a distance from said wall (12), said borehole (10) being equipped with a tie rod or anchor nail comprising a cylindrical anchor bar (20) extending in said borehole between said distal end and a sealed portion (22) in said resistant ground (100), said method comprising the steps of: • fit said sealing plug (30) onto said anchor bar (20), upstream of said drilling, • fit said pusher tube (40) onto said anchor bar (20) until it comes into contact with said sealing plug (30), • exert a pushing force on said pusher tube (40) so as to cause the sealing plug (30) to move in said borehole (10) between said proximal end and a sealing position, • remove the pusher tube (40) once the sealing plug (30) is in place in said borehole, • install a formwork (44) at the proximal end, said method being characterized in that it further comprises the following step: • pour a filling grout (42) into said borehole (10) up to the limit of disgorging of said borehole delimited by said formwork.

Images