EP3754154B1 - Machine for drilling a floor covered with a porous layer, and corresponding method - Google Patents

Description

Technical area

The present invention relates to the field of drilling techniques in the ground, and more particularly to so-called small perforation drilling techniques under fluid circulation.

Prior technique

It is known, in order to install an anchor, that is to say a micro-pile, in the ground, to first drill a hole by rotating a cutting tool which will excavate the ground. During drilling, a liquid, called drilling fluid, is generally injected in order to cool and lubricate the cutting tool and to evacuate the cuttings.

A reinforcement is then placed in the borehole, or else the tool is left in the borehole with its drive rod, before injecting a sealing grout therein.

However, such a technique of drilling under fluid circulation can damage the ground of the workplace, or platform, in particular due to the infiltration of the drilling fluid all around the drilling and due to the mechanical stresses exerted at the level of the layer of surface. This is particularly problematic in the case of soils having a porous layer which must be preserved all around the borehole, such as boreholes on railway installations which have an upper layer of ballast.

One solution to protect a platform against infiltration is to recover the fluid at the drill head. Such a solution is usually done by digging a pit into which a suction (pump) is plunged. Alternatively, there are also tanks drilled in line with the borehole and fitted with a suction mouth, which makes it possible to avoid digging the pit.

However, the digging of a pit or the installation of drilled trays at the right of the borehole is restrictive and makes the borehole dependent on the successful completion of previous stages.

Furthermore, in order to protect the surface ground layer, it is also possible to use a casing on the layer concerned.

However, for sealing by casing to be effective, it is generally necessary to use equipment provided with a double head, that is to say allowing independent rotation of the tube and the rod. However, such double-headed equipment is expensive and bulky, which limits its ease of movement.

FR2998593 and FR2869066 disclose known drilling techniques using a protection tube.

Disclosure of Invention

The present invention aims to solve the various technical problems mentioned above. In particular, the present invention aims to provide a machine making it possible to limit the infiltration of drilling fluid and to preserve the upper layer of the drilled soil. More specifically, the present invention aims to provide a drilling machine that does not deconstruct the platform and does not require the installation of a recovery tank.

Thus, according to one aspect, a machine is proposed for drilling, under fluid circulation, a ground covered with a porous layer, for example a layer of ballast. The machine comprises a drive head for rotating a drill pipe, and means for circulating a drilling fluid configured to inject a drilling fluid through the drill pipe.

The machine is also configured to insert, through the porous layer, a shroud extending around the drill pipe and leaving an intervening tubular space between the drill pipe and the shroud. The machine also comprises first means for recovering the drilling fluid configured, during the insertion of the protection tube through the porous layer, to suck, from the upper end of the protection tube, the drilling fluid coming from the drill rod, present at the lower end of the protective tube and rising, preferably, via said intermediate tubular space.

Thus, the machine according to the present invention uses a protective casing, in addition to the drill rod, without using a double head, to preserve the integrity of the platform, and in particular of the porous layer, and ensures sealing by continuous suction at the casing head. It is then possible to have autonomous use of the machine that does not require any previous step, such as as the installation of a pit or drilled tanks, while limiting the infiltrations of drilling fluid, in particular in the porous layer.

Preferably, the machine also comprises second means for recovering the drilling fluid, the second recovery means being configured to evacuate the drilling fluid coming from the drill rod and emerging via the upper end of the protection tube, preferably via said intermediate tubular space, when the protection tube is positioned through the porous layer.

When the porous layer has been crossed, the protection tube remains in place, to continue to isolate the drilling, and in particular the circulation of drilling fluid, from the porous layer. Moreover, the protective tube is detached from the machine, and in particular from the drive head. At the same time, the drilling tool continues to dig, under the porous layer, with a circulation of fluid: the latter is then recovered through the intermediate tubular space between the protection tube and the drill pipe.

Preferably, the first and second recovery means comprise a common pump and a connecting means configured to connect the common pump to the first recovery means during the insertion of the protective tube through the porous layer, and to connect the common pump to the second recovery means when the protection tube is positioned through the porous layer.

As indicated above, the drilling fluid is not recovered in the same way in the different stages of drilling, in particular because the protection tube is inserted gradually with the drill pipe at first, then remains static in a second phase. time, when positioned through the drilling layer. Thus, the recovery means used are different according to the drilling steps, but can be connected to the same pumping means in order to limit the costs and the volume of the machine.

Preferably, the second recovery means are configured to be positioned at the upper end of the protection tube when the protection tube is positioned through the porous layer, the second recovery means comprising a reservoir, preferably in the form of crown, into which the drilling fluid coming out of the protection tube is poured, and a peripheral seal, preferably circular, which creates a seal between the tank and the outer wall of the protection tube.

Once the protection tube has been positioned through the porous layer, the upper end of the latter generally comes flush with the surface of the drilled ground. Thus, the drilling fluid injected at the level of the drilling tool can rise alone, under the effect of the pressure and/or the flow rate, as far as said upper end of the protection tube. It no longer suffices then, to recover this drilling fluid, to collect it in a reservoir situated at the upper end of the protection tube, and to suck it up with a pump.

Preferably, the peripheral seal is an inflatable seal. The inflatable seal allows easy installation at the upper end of the protection tube, while guaranteeing a desired seal thanks to the control of the pressure applied in the inflatable seal.

Preferably, the drive head is configured to also drive the protection tube in rotation, preferably at the same time as the drill pipe, during the insertion of the protection tube through the porous layer.

The rotational drive of the protection tube facilitates its insertion into the ground, and in particular through the porous layer, at the same time as the drill pipe. Such driving does not require dual head hardware, but can be performed simultaneously with the drill pipe. Once the protective tube has been positioned, all you have to do is separate it from the drive head to leave it in place, and continue only with the drill rod.

Preferably, the drive head comprises means for mounting the drill rod, having a first determined diameter, and means for mounting the protection tube, having a second determined diameter greater than the first determined diameter.

In such an embodiment, the drill pipe and the protection tube are mounted on the head by mounting means which may differ only in their diameter. This facilitates the use of the machine, allowing installation and removal procedures which are similar for the protection tube and the drill pipe.

Preferably, the first fluid recovery means are mounted on the drive head, for example above the protection tube mounting means.

Such a mounting of the first recovery means on the drive head makes it possible to maintain suction at the upper end of the protective tube throughout the duration of depression of said protective tube through the porous layer and the underlying layer. underlying.

According to another aspect, there is also proposed a work train comprising a machine for drilling a ground covered with a porous layer as described above.

As indicated above, the drilling machine has been designed in such a way as to allow the use of standard equipment, and not heavy equipment such as a double head or specific duplicate equipment for the protective tube on the one hand and for the drill rod on the other hand. It then becomes possible to install it on a railway vehicle, such as a works train, in order to be able to move it along the site, as the work progresses.

Preferably, the work train comprises a drilling fluid reservoir connected to the drive head, drilling fluid suction means configured to be connected to the recovery means, and cement slurry supply means configured to be connected to the drive head.

Such a work train can thus transport the various elements necessary for the operation of the machine for drilling and for carrying out the work.

Preferably, the works train also includes a sludge recovery system, for example a settling tank, mounted downstream of the recovery means.

In particular, the sludge recovery system can be configured to operate with the sludge from the first recovery means and from the sludge from the second recovery means. The mud recovery system makes it possible in particular to recover part of the drilling fluid directly from the work train to reuse it in situ, and makes it possible to store the material removed during drilling in order to limit the impact of the work on the site.

According to another aspect, there is also proposed a method of drilling, under fluid circulation, in ground covered with a porous layer, for example a layer of ballast. According to the method, a drill pipe is rotated, and a drilling fluid is injected through the drill pipe, preferably while the drill pipe is rotating.

During a first step, a protective tube extending around the drill pipe and leaving an intermediate tubular space between the drill pipe and the protective pipe is inserted through the porous layer, and suction is taken from the upper end of the protection tube, the drilling fluid coming from the drill pipe, present at the lower end of the protection tube and rising, preferably, via said intermediate tubular space, when the protection tube is inserted through the porous layer.

Preferably, during a second step, when the protection tube is positioned through the porous layer, the protection tube is left in place and the drilling fluid coming from the drill pipe and emerging through the upper end of the tube is evacuated. protection, preferably via said intermediate tubular space.

Preferably, during the first step, the protection tube is driven at the same time as a first part of drill rod equipped, at its end, with a tool, then, during the second step, a second part of rod is assembled to the first drill pipe part and the two drill pipe parts are rotated while injecting a drilling fluid therethrough and discharging the fluid emerging from the upper end of the protection tube, preferably via said intermediate tubular space.

Brief description of the drawings

• [ Fig. 1 ] The figure 1 shows a perspective view of the drilling machine according to the invention;
• [ Fig. 2 ] The figure 2 details the circulation of fluids from the machine to drill during the installation of the protection tube;
• [ Fig. 3 ] The figure 3 illustrates the two machine configurations for drilling when installing the protection tube and when the protection tube is installed;
• [ Fig. 4 ] The figure 4 illustrates the various successive stages of implementation of the drilling process with the drilling machine illustrated in figure 1 ; and
• [ Fig. 5 ] The figure 5 illustrates part of a work train with a drilling machine as shown in figure 1 .

Description of embodiments

On the figure 1 , there is shown a machine for drilling 1 according to the present invention. The drilling machine 1 thus comprises a support 2 on which is mounted a frame 4.

The support 2 is intended to come, jointly, on a railway carrier (not shown), conventionally a railway wagon, making it possible to transport and route the machine for drilling 1 along the rails R of a railway track. Such an embodiment is particularly advantageous when the drilling machine 1 is used to install catenary pylon micro-piles along the railway track, through the layer of ballast.

In order to deploy and store the machine for drilling 1 on the wagon, the frame 4 is rotatably mounted on the support 2, with respect to a vertical axis: it is thus possible to position the drilling tool next to the railway carrier , or above the railway carrier, depending on whether the drilling machine 1 must install a pylon micro-pile or else must be moved.

The drilling machine 1 also comprises a mast 6 extending in a longitudinal direction, and pivotally mounted on the frame 4, with respect to a horizontal axis, for example via cylinders 8. The cylinders 8 thus make it possible to position the mast 6 horizontally, in particular above the railway carrier, when the drilling machine 1 must be moved, or else vertically, as illustrated in the figure 1 , when the machine for drilling 1 needs to install a pylon micro-pile.

In the drilling position, as shown in figure 1 , the mast 6 has a lower end 6a intended to bear against the surface to be drilled.

The drilling machine 1 further comprises a carriage 10 mounted to slide along the mast 6. The carriage 10 can be moved along the mast 6 by means known elsewhere and not shown here.

The carriage 10 comprises in particular a rotation table 12 configured to rotate a drive head 14 on which the drilling tool will be mounted. As will be explained below, the drilling tool of the present drilling machine 1 comprises on the one hand a drill rod and on the other hand a protection tube independent of the drill rod and surrounding the latter at the level of the upper portion of the borehole.

In particular, and as illustrated in picture 2 , the drive head 14 comprises in particular first mounting means 16, for example an internal thread, configured to allow the mounting of a drill rod 18, comprising a corresponding external thread, on the drive head 14. The head drive 14 also comprises second mounting means 20, for example an external thread, configured to allow the mounting of a protection tube 22, comprising a corresponding thread, on the drive head 14.

As can be seen, the first mounting means 16 and the second mounting means 20 are arranged coaxially on the drive head 14, in order to obtain a mounting of the drill pipe 18 parallel to the mounting of the protection tube 22 , and include different diameters corresponding to those of drill pipe 18 and shroud 22. Importantly, drill pipe 18 and shroud 22 are simultaneously driven together by drive head 14 when they are mounted on means 16 and 20 respectively.

In order to facilitate drilling, the drilling machine 1 also comprises a circulation circuit for a drilling fluid. The drilling fluid can for example be water, and is circulated by the drilling machine 1 in the drilling zone in order to extract the drilled material therefrom.

The drive head 14 thus comprises a drilling fluid supply channel 24 connected to means for supplying and circulating under pressure a drilling fluid (not shown). Drill pipe 18 also includes an axial channel 26 which comes into fluid communication with supply channel 24 of drive head 14 when drill pipe 18 is mounted on drive head 14. The drilling fluid is thus injected under pressure inside the drill pipe 18, in order to come out at the other end of the drill pipe 18 on which is mounted a cutting tool 28 (see figure 3 ).

In order to protect the platform in which the drilling is carried out, and in particular in order to prevent the drilling fluid, with the material it entrains, from spreading around the drilling zone, and in particular the layer of porous P of ballast, the shroud tube 22 is designed with an inner diameter greater than the outer diameter of the drill pipe 18, so as to create, when the drill pipe 18 and the shroud pipe 22 are mounted on the drive head 14, an intermediate tubular space 29 extending from the lower end of the protection tube 22 to the first and second mounting means 16, 20 of the drive head 14.

Furthermore, the drive head 14 is configured to extend the interposed tubular space 29 beyond the first and second mounting means 16, 20, as far as the first means 30 for recovering drilling fluid. As shown in configuration (1) of the figure 3 , the first recovery means 30 are mounted on the drive head 14, above the first and second mounting means 16, 20, and make it possible to recover, or to suck up thanks to suction means not shown , the drilling fluid charged with drilled material and rising from the bottom of the borehole via the interposed tubular space 29. This recovery, or aspiration, of the drilling fluid loaded with drilled material takes place progressively, and throughout the entire descent of the drill pipe 18 and of the protection tube 22 in the ground, and more particularly in the porous upper layer P of ballast.

Furthermore, and as illustrated in configuration (2) of the figure 3 , the drilling machine 1 also comprises second recovery means 32 mounted at the lower end 6a of the mast 6 and configured to recover, or suck up, the drilling fluid loaded with drilled material exiting the tube protection 22 when the latter is positioned through the porous layer P of ballast and is detached from the drive head 14. In particular, the drilling machine 1 may comprise suction means (not shown), for example a single pump configured to be connected to the first recovery means 30 and/or to the second recovery means 32 depending on the step of the drilling method. For example, the suction means may comprise a connecting means to be connected to the first recovery means 30 then to the second recovery means 32.

The second recovery means 32 may for example comprise a reservoir in the form of a crown mounted around the protection tube 22, and a circular gasket, preferably inflatable, configured to create a seal between the outer wall of the protection tube 22 and the reservoir of the second recovery means 32. The drilling fluid, loaded with drilled material, emerging through the upper end of the protection tube 22 then flows into the reservoir of the second recovery means 32 before being, for example , sucked into a treatment means (not shown) such as a settling tank for separating the drilling fluid and the drilled material and then reusing the drilling fluid.

Using the figure 4 , we will now describe an example of a drilling method, under fluid circulation, of a ground S covered with a porous layer P, for example of ballast.

In step (A), the mast 6 is positioned vertically with its lower end 6a resting on the surface to be drilled. The carriage 10 driving the drive head in translation is positioned at the top of the mast 6, with the drive head 14 located in line with the area to be drilled.

In step (B), the drive head 14 is pivoted, at the level of the carriage 10, by 90° in order to free access to the zone to be drilled.

In step (C), the protection tube 22 is positioned above the zone to be drilled, at the lower end 6a of the mast 6 forming a guide for the protection tube 22.

In step (D), the first portion of the drill rod 18, which has the cutting tool 28 at its end and which constitutes an armature with lost tool, is positioned inside the protective tube 22, as can be seen in the sectional portion shown in step (D).

At step (E), the drive head 14 is again pivoted, at the level of the carriage 10, by 90° to return to the right of the zone to be drilled, above the protection tube 22 and the rod drilling 18.

In step (F), the carriage 10 is lowered so as to allow the mounting of the drill pipe 18 on the corresponding first mounting means 16, then the mounting of the protection tube 22 on the corresponding second mounting means 20 .

Once the protection tube 22 and the drill pipe 18 are mounted on the drive head 14, they are rotated by the drive head at the same time as the carriage 10 descends along the mast 6. The drill pipe 18 and shroud 22 therefore begin to drill through the porous layer P of ballast and sink into it, until shroud 22 is driven into and through the porous layer P of ballast (step (G)). Throughout step (F), the drilling fluid is, on the one hand, injected, via the drive head 14, through the drill rod 18 to emerge at the level of the cutting tool 28, then , on the other hand, re-sucked from the upper end of the protection tube 22, via the intermediate tubular space, by the first recovery means 30 mounted on the drive head 14. Indeed, the drilling fluid having to "raise" the entire length of the protection tube 22 as far as the drive head which may be located very above the surface to be drilled, the injection pressure of the drilling fluid may prove to be insufficient, so that a forced suction at the level of the first recovery means 30 is then necessary. Thus, throughout step (F), the drilling fluid is recovered as it is injected into the drill pipe 18, which makes it possible to limit the impact of its circulation on the zone surrounding the drilling.

In step (G), the protective tube 22 is positioned through the porous layer P of ballast, and can then be separated from the drive head 14. Once separated, the second recovery means 32 can be secured to the protective tube 22, for example the inflatable annular seal can be inflated so as to seal the connection between the protective tube 22 and the reservoir of the second recovery means 32.

In step (H), the carriage 10 carrying the drive head 14 is first partially raised so as to raise the drill rod 18 sufficiently to be able to separate it in turn from the drive head 14, then the carriage 10 is raised to the top of the mast 6.

In step (I), the drive head 14 is pivoted, at the level of the carriage 10, by 90° in order to free access to the zone to be drilled, and a second portion of the drill rod 18 is positioned then mounted on the first portion of the drill pipe 18.

At step (J), the drive head 14 is again pivoted, at the level of the carriage 10, by 90° to return to the right of the zone to be drilled, above the drill rod 18 (which comprises now two portions), and this is then mounted on the drive head 14.

At step (K), the drill pipe 18 is rotated by the drive head 14 at the same time as the carriage 10 descends along the mast 6. The drill pipe 18 therefore continues to drill the ground S , beyond the lower end of the protection tube 22. Throughout step (K), the drilling fluid is, on the one hand, injected, via the drive head 14, through the drilling 18 to emerge at the level of the cutting tool 28, then, on the other hand, circulates, via the intermediate tubular space, to the upper end of the protection tube 22. The upper end of the protection 22 being free and located slightly above the drilled surface, the drilling fluid loaded with drilled material can then come out on its own, under the effect of the injection pressure, and flow into the reservoir of the second means recovery 32 to then be sucked by the suction means. Thus, throughout step (K), the drilling fluid is recovered as it is injected into the drill pipe 18, which makes it possible to limit the impact of its circulation on the zone surrounding the drilling.

In step (L), the carriage 10 carrying the drive head 14 is first partially raised so as to raise the drill rod 18 sufficiently to be able to separate it from the drive head 14, then the Carriage 10 is completely raised to the top of mast 6 so as to be able to reproduce, as many times as desired, steps (I) to (L).

Once the steps for installing the drill rod 18 have been carried out, a cement slurry can then be injected into the drill rod in order to seal the latter in the ground S and thus obtain a catenary pylon micro-pile.

Thus, a micro-pile is obtained formed on the one hand by a drill rod and on the other hand by a protective tube which reinforces the maintenance of the drill rod in the ground. The protection tube is positioned in the ground, through a layer of ballast, without the latter or the surface of the zone to be drilled being impacted by the drilling carried out.

Moreover, thanks to its compactness, in particular because of its single head, and its limited weight, the drilling machine 1 is suitable for being installed on a railway wagon and for moving quickly, with significant bends. Thus, it is possible to obtain a works train 34, part of which is illustrated on the figure 5 , comprising a drilling machine 1 as described previously, and making it possible to install the micro-piles of the catenary pylons along the railway line on which it circulates.

The work train 34 can thus comprise, in addition to the drilling machine 1, means for supplying and circulating, under pressure, a drilling fluid (not shown), connected to the drive head, means slurry supplies (not shown) configured to be connected to drive head 14 when sealing drill pipe 18 in the borehole.

The work train 34 can also comprise suction means 36 for the drilling fluid loaded with drilled material, configured to be connected to the first or to the second recovery means 30, 32, as well as a settling tank 38 mounted downstream of the suction means 36 and making it possible to separate the drilling fluid and the drilled material, in order to allow reuse of the drilling fluid.

Thus, thanks to the drilling machine and the work train comprising such a drilling machine, it becomes possible to easily install micro-piles for catenary pylons, along a railway track, while preserving the upper layer of ballast, and more generally the environment of the railway.

Claims (15)

1. A machine for drilling (1), under fluid circulation, a ground (S) covered with a porous layer (P), for example a ballast layer, wherein the machine (1) includes:

   - a drive head (14) for driving in rotation a drill pipe (18), and

   - means for circulating a drilling fluid configured to inject a drilling fluid through the drill pipe (18),

   wherein the machine (1) is also configured to insert, through the porous layer (P), a protection tube (22) extending around the drill pipe (18) and leaving a tubular interspace (29) between the drill pipe (18) and the protection tube (22), and wherein the machine (1) also comprises first means (30) for recovering the drilling fluid configured, upon insertion of the protection tube (22) through the porous layer (P), to draw, from the upper end of the protection tube (22), the drilling fluid coming from the drill pipe (18) and present at the lower end of the protection tube (22).
2. The machine (1) according to claim 1, wherein the first drilling fluid recovery means (30) are configured, upon insertion of the protection tube (22) through the porous layer (P), to draw, from the upper end of the protection tube (22), the drilling fluid coming from the drill pipe (18), present at the lower end of the protection tube (22) and traveling back via said tubular interspace (29).
3. The machine (1) according to claim 1 or 2, also comprising second means (32) for recovering the drilling fluid, the second recovery means (32) being configured to discharge the drilling fluid coming from the drill pipe (18) and exiting through the upper end of the protection tube (22), via said tubular interspace (29), when the protection tube (22) is positioned through the porous layer (P).
4. The machine (1) according to claim 3, wherein the first and second recovery means (30, 32) include a common pump and a connection means configured to connect the common pump to the first recovery means (30) upon insertion of the protection tube (22) through the porous layer (P), and to connect the common pump to the second recovery means (32) when the protection tube (22) is positioned through the porous layer (P).
5. The machine according to claim 3 or 4, wherein the second recovery means is configured to be positioned at the upper end of the protection tube when the protection tube is positioned through the porous layer, the second recovery means including a preferably ring-shaped reservoir, wherein the drilling fluid exiting the protection tube is poured, and a preferably circular peripheral seal creating a seal between the reservoir and the external wall of the protection tube.
6. The machine (1) according to claim 5, wherein the peripheral seal is an inflatable seal.
7. The machine (1) according to any of claims 1 to 6, wherein the drive head (14) is configured to also drive in rotation the protection tube (22), preferably at the same time as the drill pipe (18), upon insertion of the protection tube (22) through the porous layer (P).
8. The machine (1) according to claim 7, wherein the drive head (14) includes means (16) for mounting the drill pipe (18), having a first determined diameter, and means (20) for mounting the protection tube (22), having a second determined diameter greater than the first determined diameter.
9. The machine (1) according to claim 8, wherein the first means (30) for recovering the fluid are mounted on the drive head (14), for example above the protection tube (22) mounting means (20).
10. A work train (34) comprising a machine (1) for drilling a ground (S) covered with a porous layer (P) according to any of claims 1 to 9.
11. The work train (34) according to the preceding claim, comprising means for supplying a drilling fluid connected to the drive head (14), means for drawing the drilling fluid (36) configured to be connected to the recovery means (30, 32), and means for providing a cement grout configured to be connected to the drive head (14).
12. The work train (34) according to the preceding claim, also comprising a sludge recovery system, for example a settling tank (38), mounted downstream of the recovery means (30, 32).
13. A method for drilling, under fluid circulation, a ground covered with a porous layer, for example a ballast layer, wherein

    - a drill pipe (18) is driven in rotation, and

    - a drilling fluid is injected through the drill pipe (18), preferably during the rotation of the drill pipe (18),

    wherein, during a first step:

    - a protection tube (22) extending around the drill pipe (18) and leaving a tubular interspace (29) between the drill pipe (18) and the protection tube (22) is inserted through the porous layer, and

    - the drilling fluid coming from the drill pipe (18), present at the lower end of the protection tube (22) and traveling back via said tubular interspace (29), is drawn from the upper end of the protection tube (22), upon insertion of the protection tube (22) through the porous layer.
14. The drilling method according to the preceding claim, wherein, during a second step, when the protection tube (22) is positioned through the porous layer, the protection tube (22) is left in place and the drilling fluid coming from the drill pipe (218) and exiting through the upper end of the protection tube (22) via said tubular interspace (29) is discharged.
15. The drilling method according to claim 14, wherein during the first step, the protection tube (22) is driven at the same time as a first part of the drill pipe (18) equipped, at its end, with a tool (28), then, during the second step, a second drill pipe part is assembled to the first drill pipe part and the two drill pipe parts (18) are driven in rotation while injecting a drilling fluid therethrough and discharging the fluid exiting through the upper end of the protection tube (22), via said tubular interspace (29).

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