Drilling tool and method for creating a hole in the soil

Abstract

The invention relates to a drilling tool (10) for creating a borehole in the ground, comprising a tubular drill shaft (12), at least one removal device (18, 21, 22) designed for removing soil material, a supply device (30) for supplying a fluid through the drill shaft via at least one outlet opening (35) for the fluid into the borehole, and at least one mixing element extending radially to the drill shaft, which is arranged on the drill shaft above the removal device (21) and is designed for mixing soil material with the fluid.At least one first outlet opening (35) in the area of ​​the removal device and at least one second outlet opening is arranged axially spaced from the at least one first outlet opening, wherein at least one actuating device (50) is provided on the feed device (30) with which the at least one first outlet opening (35) and / or the at least one second outlet opening can be blocked, wherein fluid can be selectively introduced into the bore via the at least one first outlet opening (35) and / or the at least one second outlet opening.

Description

[0001] The invention relates to a drilling tool for creating a borehole in the ground, comprising a tubular drill shaft, at least one removal device designed for removing soil material, a supply device for supplying a fluid through the drill shaft via at least one outlet opening for the fluid into the borehole, and at least one mixing element extending radially to the drill shaft, which is arranged axially spaced on the drill shaft from the removal device and is designed for mixing soil material with the fluid, according to the preamble of claim 1.

[0002] The invention further relates to a method for creating a borehole in the ground according to the preamble of claim 11.

[0003] Drilling tools of this type are used particularly in specialist foundation engineering for the construction of foundation elements in the ground. The drilling tool may, for example, be designed with an auger that is driven into the ground, removing soil material along the way. The soil material, crushed by a removal device on the auger, can be conveyed upwards to an upper section of the borehole. During drilling, a curing slurry can be introduced through an outlet on the drill shaft. Mixing elements on the drill shaft mix the slurry with the crushed soil material to produce a so-called soil mortar in situ. Once a final depth is reached, the drilling tool is withdrawn from the borehole. If necessary, further injection of the drilling slurry and rotation of the drilling tool are carried out to produce a finished soil mortar, which can then harden to form the foundation element.

[0004] For a particularly good mixing result, it is known to prefer at least one radially directed conduit channel on the borehole shaft, so that suspension can be introduced over a larger diameter range of the borehole.

[0005] A drilling tool according to the preamble of claim 1 is known from US 5,304,016 A. Further known drilling tools are shown in publications DE 10 2004 005 967 A1, WO 2015 / 140468 A1 and EP 0 441 169 A2.

[0006] The invention is based on the Task The basis is to specify a drilling tool and a method for creating a borehole in the ground, with which a particularly good introduction of fluid into the borehole can be achieved.

[0007] The problem is solved, firstly, by a drilling tool having the features of claim 1 and, secondly, by a method having the features of claim 11. Preferred embodiments of the invention are specified in the dependent claims.

[0008] The drilling tool according to the invention is characterized in that at least one first outlet opening is arranged in the area of ​​the removal device and at least one second outlet opening is arranged axially spaced from the at least one first outlet opening, and that at least one actuating device is provided on the feed device with which the at least one first outlet opening and / or the at least one second outlet opening can be locked, wherein fluid can be selectively introduced into the bore via the at least one first outlet opening or the at least one second outlet opening.

[0009] A primary concept of the invention is to provide multiple outlet openings along the drill shaft. A further concept is the provision of an actuating device with which at least one outlet opening can be selectively blocked. With the drilling tool according to the invention, it is thus possible to control the introduction of fluid into the bore at specific times via specific outlet openings.

[0010] For example, during drilling, fluid can be introduced in the area of ​​the cutting unit, allowing the removed drill cuttings to be mixed directly with the fluid, particularly a drilling fluid, at the cutting unit. This allows for a particularly good mixing result even during drilling. When the drill bit is withdrawn from the borehole, further introduction of drilling fluid in the area of ​​the cutting unit can impair the mixing result, as drilling fluid introduced into the borehole at the lower end of the drill bit can hardly be mechanically stirred when the drill bit is pulled upwards.

[0011] With the drilling tool according to the invention, for example, lower first outlet openings can be blocked via the adjusting device, while further supply of suspension can occur via axially spaced upper second outlet openings. When the still-rotating drilling tool is withdrawn, the suspension introduced from above can be further mixed with the excavated soil material by the drilling tool with its arranged mixing elements and / or the removal device. In this way, a particularly good mixture and, in particular, a high-quality and very uniform soil mortar can be efficiently produced. This allows for the creation of particularly strong foundation elements in the ground.

[0012] In principle, various configurations for supplying a fluid into a bore can be set using the at least one actuating device. For example, supply can occur via only one outlet or simultaneously via several outlets. According to the invention, the at least one actuating device allows the at least one first outlet and the at least one second outlet to be alternately blocked, whereby fluid can be introduced into the bore via the at least one first outlet or the at least one second outlet while the at least one second outlet or the at least one first outlet is blocked. This alternate blocking capability ensures that fluid cannot be introduced simultaneously via two axially spaced outlets. The fluid can be a flowable medium, in particular a liquid or a suspension.

[0013] Generally, the drilling tool can only have a removal device for soil material at its lower end. According to a further development of the invention, under certain soil conditions, it may be advantageous for at least one first removal device to be arranged at a lower end of the drill shank and at least one second removal device to be arranged axially above the first removal device. In this way, the second removal device can be provided at an upper end of the drilling tool, so that soil material that has fallen in along the borehole wall can be reliably removed, even when the drilling tool is withdrawn. The outlet openings are preferably located on and / or between the two removal devices.

[0014] It is particularly advantageous for at least one mixing element to be arranged between the first and second excavation units. This ensures that the soil material excavated during both drilling and retraction is reliably mixed by the mixing element. Preferably, several mixing elements are arranged along the drill shaft.

[0015] According to a further embodiment of the invention, a particularly good mixing result can be achieved by the removal device having at least one support bar extending radially to the drill shaft, on which removal elements for removing soil material are arranged, and by forming a first channel on or in the support bar, along which one or more outlet openings are provided. Thus, fluid can be introduced via the support bar of the removal device across the diameter of the bore. This ensures particularly good distribution and mixing.

[0016] A particularly good mixing result can be achieved according to another embodiment of the invention by providing the mixing element with a support arm and a second conduit channel on or in the support arm, along which one or more outlet openings are provided. The mixing element can consist solely of the support arm or of additional stirring or mixing elements attached to the support arm. A support arm of the at least one mixing element extending radially away from the bore shaft also ensures good distribution and mixing across the bore diameter.

[0017] Another preferred embodiment of the invention consists in at least one outlet opening being arranged directly on the drill shaft. In particular, one or more outlet openings can be provided at the lower end region of the drill shaft close to the removal device, since particularly strong mixing occurs there due to the mechanical energy input.

[0018] In principle, the actuating device can be designed in any suitable way, for example with electrically controlled control valves. A particularly advantageous embodiment of a drilling tool according to the invention is that the actuating device comprises at least one movable actuating element, which is adjustable between a closed and an open position. The actuating elements can be flaps or slides, which can be individually actuated by actuators or mechanically by a central actuating linkage. Generally, one or more actuating elements can be arranged centrally in the drill shaft, so that, for example, an opening or release of flow to a lower region of the drill shaft is enabled. The actuating element can block or release a passage in the drill shaft. According to a further development of the invention, it is particularly advantageous that each conduit channel is assigned an actuating element.Thus, the radially oriented channels can be configured to allow fluid to be introduced through them. A control element can also be used to lock or unlock a portion of the drill shank. Particularly reliable control of the at least one control element by the actuating device can be achieved by allowing the actuating device to be activated by changing the rotation of the drill shank. This allows for a continued simple and robust design of the drilling tool.

[0019] In particular, this can be achieved by making at least one actuating element mechanically adjustable via a cam mechanism. For example, a mechanical cam track can be provided along the drill shaft, along which an actuating element or cam of the actuating element rests and is guided. By changing the rotation of the drill shaft, the actuating element with the cam can be moved along the cam track, allowing the actuating element to assume either the closed or the open position. This enables simple mechanical control.In particular, when drilling with a predetermined direction of rotation, the opening of at least one lower exit opening can be achieved, while when the drilling tool is withdrawn from the borehole with the opposite direction of rotation, the at least one lower exit opening is automatically closed by the predetermined cam mechanism.

[0020] The invention further relates to a method for creating a borehole in the ground, wherein the previously described drilling tool according to the invention is used and a fluid is selectively introduced into the borehole via at least one first outlet opening and / or at least one second outlet opening.

[0021] The inventive method allows the advantages described above to be achieved when using the inventive drilling tool.

[0022] Particularly when using a curable liquid or suspension, a practical method variant can be implemented by introducing the fluid during drilling through at least one first outlet opening located in a lower end region of the drill shank, and by introducing the fluid into the borehole through at least one second outlet opening above the first outlet opening, while rotating the drill bit. This method can be used, in particular, for producing high-quality soil mortar in the borehole.

[0023] In a further development of the inventive method, it is particularly advantageous to introduce a curable suspension as the fluid, whereby a foundation element is produced in the ground within the borehole. After the drilling tool is withdrawn, the soil mortar produced in the borehole from the excavated soil material and the introduced curable fluid can harden to form a foundation element, in particular a foundation pile.

[0024] The inventive method enables the production of a particularly well-mixed and thus very homogeneous soil mortar, which hardens to form a high-quality foundation element. The risk of defects forming in the foundation element is significantly reduced or even completely eliminated.

[0025] The invention is further explained below with reference to a preferred embodiment. The drawings show: Fig. 1 a side view of a drilling tool according to the invention; Fig. 2 view of the drilling tool from Fig. 1 from below; Fig. 3 a cross-sectional view of the drilling tool according to the Figures 1 and 2 ; and Fig. 4 an enlarged detail view corresponding to the marked section in Fig. 3 for the positioning device of a drilling tool according to the invention.

[0026] A drilling tool 10 according to the invention is used in connection with the Figures 1 to 4The drilling tool 10 comprises a tubular drill shaft 12 with an internal cavity 14. A central pilot tip 20 and a downward-facing first removal device 21 are arranged on the underside of the drill shaft 12. The first removal device 21 has a short helix 18 with two through-holes 19. Tooth-like removal elements 26 for removing soil material are arranged along two radially extending first support ribs 24 in a generally known manner. The first support ribs 24 are hollow and form a first conduit 32, which extends radially. The first conduit 32 is connected to a central feed device 30 with a central conduit 31 in the hollow drill shaft 12 for supplying a liquid or suspension. The liquid or suspension can flow out through first outlet openings 35 along the first support ribs 24.

[0027] At one upper end of the drill shaft 12, a plug-type drill pipe connection 16 is arranged to connect the drill tool 10 to a hollow drill string (not shown), which is rotatably mounted and driven on a preferably mobile drilling rig in a generally known manner. Liquid or suspension can be supplied from the drilling rig to the feed device 30 in the drill tool 10 via the drill string.

[0028] Immediately below the drill pipe connection 16, an upwardly directed second removal device 22 with tooth-like removal elements 26 is arranged. The removal elements 26 of the second removal device 22 are directed upwards, unlike the removal elements 26 of the first removal device 21, in order to crush any soil material that may have fallen in during a rotating retraction of the drill bit 10 from a borehole and to ensure reliable retraction of the drill bit from the borehole in the ground.

[0029] The second removal device 22 can also have two opposing and radially oriented second support bars 25, which are hollow to form a second conduit 33. The second conduit 33 open into the central conduit 31 of the feed device 30, as can be clearly seen in Fig. 4 is shown.

[0030] Between the first removal device 21 and the second removal device 22, axially and / radially offset mixing elements 40 with radially directed support arms 42 are formed on the drill shaft 12, on which mixing blades 44 can be arranged.

[0031] Below the second removal device 22, an actuating device 50 with a bar- or plate-shaped actuating element 52 is formed on the drill shaft 12, by which the central line 31 of the feed device 30 between the first removal device 21 and the second removal device 22 can be shut off or opened. In the Figures 3 and 4 The actuating element 52 is shown in the closed or locking position. The actuating element 52 protrudes at one end from the bore shaft 12, with a radially upwardly directed cam bolt 56 being provided at the outwardly projecting end to form a cam actuating mechanism 54.

[0032] The cam pin 56 engages in a guide groove 59 in an arc-shaped cam track 58, which is located on the outside of the drill shank 12. The guide groove 59 runs circumferentially and is approximately semicircular, but with a varying distance from the drill axis. This forms the cam-actuated adjustment mechanism 54, whereby a relative rotation between the cam track 58 with the guide groove 59 and the cam pin 56 changes its radial position relative to the drill axis. Through the connection between the cam pin 56 and the actuating element 52, the latter can be adjusted between a closed and an open position by a relative rotation.

[0033] To effect a relative rotation, the arc-shaped cam track 58 can be attached to a bearing sleeve 60, which is rotatably mounted on the outside of the drill shank 12. The upper second cutting device 22 can also be arranged on the bearing sleeve 60. When the direction of rotation of the drill 10 changes, a relative rotation can thus be effected between the drill shank 12 and the bearing sleeve 60 with the cam track 58 and, if applicable, the second cutting device 22 attached to it. Thus, the adjusting device 50 can be actuated by changing the direction of rotation of the drill 10.

[0034] According to a method according to the invention, when creating and drilling a borehole with the drilling tool 10, the actuating element 52 can be brought into its opening position, so that in this position, drilling fluid or drilling suspension can be directed to the lower first outlet openings 35 and introduced directly into the borehole at the first removal device 21.

[0035] If, on the other hand, the drilling tool 10 is withdrawn from the created bore with the reverse direction of rotation, the cam mechanism 54 causes the actuating element 52 to be moved into a closing or locking position, so that any liquid or suspension supplied is introduced into the bore exclusively via the second outlet openings 36 above it on the second removal device 22.

[0036] By introducing the fluid at the upper end of the drilling tool 10, it is ensured during retraction that the rotating drilling tool 10 mixes the newly introduced fluid sufficiently intensively with the existing suspension in the borehole.

Claims

1. Drilling tool for creating a bore in the ground, comprising - a tubular drill shank (12), - at least one removal device (21, 22), which is configured to remove soil material, - a supply device (30) for supplying a fluid through the drill shank (12) through at least one outlet opening (35) for the fluid into the bore, and - at least one mixing element (40) extending radially to the drill shank (12), which is arranged on the drill shank (12) at an axial distance from the removal device (21) and is configured for mixing soil material with the fluid, - wherein at least one first outlet opening (35) along the drill shank (12) is arranged in the region of the removal device (21) and at least one second outlet opening (36) along the drill shank (12) is arranged at an axial distance from the at least one first outlet opening (35), characterized - in that at least one actuating device is provided on the supply device (30), by means of which the at least one first outlet opening (35) and / or the at least one second outlet opening (36) can be blocked, wherein fluid can optionally be introduced into the bore via the at least one first outlet opening (35) or the at least one second outlet opening (36), and - in that the at least one first outlet opening (35) and the at least one second outlet opening (36) can alternately be blocked by the at least one actuating device (50), wherein fluid can be introduced into the bore via the at least one first outlet opening (35) or the at least one second outlet opening (36), while the at least one second outlet opening (36) or rather the at least one first outlet opening (35) is blocked.

2. Drilling tool according to claim 1, characterized in that at least one first removal device (21) is arranged at a lower end portion of the drill shank (12) and at least one second removal device (22) is arranged axially above the first removal device (21).

3. Drilling tool according to claim 2, characterized in that the at least one mixing element (40) is arranged between the first removal device (21) and the second removal device (22).

4. Drilling tool according to any one of claims 1 to 3, characterized in that the removal device has at least one support bar extending radially to the drill shank (12), on which removal elements (26) for removing soil material are arranged, and in that a first conduit channel (32) is formed on or in the support bar, along which one or multiple outlet openings are provided.

5. Drilling tool according to any one of claims 1 to 4, characterized in that the mixing element (40) has a support arm (42) and in that a second conduit channel (33) is formed on or in the support arm (42), along which further outlet openings are provided.

6. Drilling tool according to any one of claims 1 to 5, characterized in that at least one outlet opening is arranged directly on the drill shank (12).

7. Drilling tool according to any one of claims 1 to 6, characterized in that the actuating device (50) comprises at least one movable actuating element (52) which can be adjusted between a closed setting and an open setting.

8. Drilling tool according to claim 7, characterized in that an actuating element (52) is assigned to each conduit channel.

9. Drilling tool according to any one of claims 1 to 8, characterized in that the actuating device can be operated by changing the rotation of the drill shank (12).

10. Drilling tool according to any one of claims 7 to 9, characterized in that the at least one actuating element (52) is mechanically adjustable by means of a link adjusting mechanism (54).

11. Method for creating a bore in the ground, characterized in that a drilling tool (10) according to one of claims 1 to 10 is used and in that a fluid is optionally introduced into the bore via the at least one first outlet opening (35) or the at least one second outlet opening (36).

12. Method according to claim 11, characterized in that during sinking-by-drilling the fluid is introduced via the at least one first outlet opening (35), which is arranged in a lower end portion of the drill shank (12), and in that the fluid is introduced into the bore via the at least one second outlet opening (36) above the first outlet opening (35), wherein the drilling tool (10) is rotated.

13. Method according to claim 11 or 12, characterized in that a curable suspension is introduced as a fluid, wherein a foundation element is produced in the bore in the ground.

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