DRILLING TOOL AND METHOD FOR CREATING A BOIL IN THE SOIL

Description

[0001] The invention relates to a drilling tool, in particular for discontinuous earth drilling, comprising a soil removal device arranged on a lower region of the drilling tool and designed for removing soil material, a receiving chamber formed on the drilling tool above the soil removal device for receiving the removed soil material, at least one passage formed for the removal of soil material from the soil removal device into the receiving chamber during drilling, a closing device for closing the at least one passage when the drilling tool is withdrawn from the borehole, and a connecting device on the upper region of the drilling tool for detachably connecting it to a drill string, according to the preamble of claim 1.

[0002] Furthermore, the invention relates to a method for creating a borehole in the ground according to claim 11.

[0003] For example, when installing foundation piles in the ground, it is known to create a hole in the soil using a soil cultivation tool, such as a drill bucket. Depending on the type of surrounding soil, the borehole can be cased or uncased. Particularly in the case of uncased boreholes, a support fluid must be used to prevent the borehole from collapsing.

[0004] When using a bucket drill, discontinuous drilling must be carried out. During drilling, the bucket fills with excavated soil material, in particular until it is completely or at least largely full. The bucket is then pulled out of the fluid-filled hole, while a drilling rig swings above the surface to an emptying position where the bucket can be emptied. The bucket is then swung back and reinserted into the borehole to perform another drilling step.

[0005] When creating a hole in the ground filled with a support fluid, a problem arises: as the soil cultivation equipment is withdrawn, a vacuum can form beneath it within the hole. If this vacuum becomes too strong, soil material can collapse from the sides into the hole. This collapsed soil material not only creates additional work to retrieve it from the hole, but also poses the risk of a so-called soil failure. In such a scenario, the material that has fallen into the hole weakens and destabilizes the surrounding soil to such an extent that significant settlement movements occur in the area around the hole. This can damage existing structures or cause construction equipment to topple over. Soil failure represents a considerable danger to people and property, so comprehensive precautions must be taken to prevent it.

[0006] To avoid such a danger caused by the formation of a vacuum under a soil cultivation device when pulling upwards, it is known to keep the retraction speed of the soil cultivation tool low so that sufficient pressure equalization can take place between the top and bottom of the soil cultivation device in the hole.

[0007] Furthermore, it is known, for example, from EP 3 879 064 A1, to provide a lateral recess in a drill bucket, which allows fluid flow along the drill bucket between the top and bottom. This limits the possible receiving space. In addition, partial lateral flow around the circumference of the drill bucket can cause it to be deflected from its central position in the borehole. This can lead to undesirable tilting in the borehole, increased wear on the drill bit and casing, and increased effort required to withdraw the drill bit from the borehole.

[0008] Another drill bucket with an approximately ring-shaped outer passage gap for fluid flow along the drill bucket is shown in DE 34 40 727 A1.

[0009] A drilling tool according to the preamble of claim 1 is shown, for example, in DE 87 16 926 U1. Further similar drilling tools are known from EP 0 974 729 A1 and CN 203 145 837 U.

[0010] The invention is based on the Task The basis is to specify a drilling tool and a method with which a hole can be created in the ground in a particularly efficient manner.

[0011] 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.

[0012] The drilling tool according to the invention is characterized in that a tubular central shaft is formed with a compensating channel which extends from at least one lower channel opening, which is arranged below or on the closure device, to at least one upper channel opening, which is arranged above the receiving space, wherein the compensating channel is designed to allow a medium to flow between the lower area and the upper area of ​​the drilling tool when the drilling tool is pulled and / or lowered in the borehole.

[0013] A fundamental aspect of the invention is to provide a compensating channel in a tubular central shaft of a drilling tool with a lower closure device that can close at least one passage to the receiving chamber at the bottom. This compensating channel has at least one lower channel opening in the lower region of the drilling tool and one upper channel opening in the upper region of the drilling tool. The compensating channel allows for a controlled, central compensating flow between the top and bottom of the drilling tool, particularly during extraction, but also when lowering the drilling tool in a borehole, especially one filled with suspension or liquid, while the passage to the receiving chamber is closed.

[0014] When a drill bit is withdrawn, especially one that largely covers the bore diameter and can act like a plug when the passage is closed, pressure equalization can occur between the area below and above the drill bit. This counteracts an undesirable suction effect during withdrawal, which could damage the borehole wall.

[0015] The central flow channel through the middle shaft effectively counteracts the risk of the drill bit becoming jammed in the borehole during vertical movement, unlike lateral flow channels. This protects both the drill bit and the borehole wall. Overall, a central equalization channel within a tubular middle shaft, featuring at least one lower and one upper opening, ensures efficient, central flow around or through the drill bit, compensating for pressure or flow fluctuations during vertical movement within the borehole. This allows for faster and more energy-efficient movement of the drill bit.

[0016] A particularly preferred embodiment of the invention is characterized in that the lower channel opening and / or the upper channel opening can be closed. Particularly during the actual drilling process, in which soil material is removed from the lower region of the drill bit, it can be advantageous to close the lower channel opening. This prevents soil material from entering the channel opening and potentially clogging the equalization channel. Closing the upper channel opening can also be advantageous to prevent the ingress or sedimentation of settling soil material from a drilling fluid and potentially clogging the upper channel opening from above.

[0017] A particularly advantageous embodiment of the drilling tool is achieved in a further development of the invention by designing the closing device for the passage to the receiving chamber to also open / close the lower channel opening. The closing device, in a manner known in principle, such as in a pipe bucket or a discontinuously operating auger, serves to keep a passage open during drilling, allowing the excavated soil material to pass into the receiving chamber, and to close the passage after the drilling step is completed. In the closed position, this prevents loose excavated soil material from falling back into the borehole from the receiving chamber of the drilling tool when the drilling tool is withdrawn from the borehole.

[0018] According to a further development of the invention, the closure device can be designed such that it is configured not only to close and open the passage to the receiving chamber, but also to close and open the lower channel opening. The lower channel opening can be arranged, in particular, close to the at least one passage to the receiving chamber, and especially in an area below the passage to the receiving chamber.

[0019] According to one embodiment of the invention, it is particularly advantageous that the closure device has a closure element which is adjustable between a closure position in which the passage to the receiving space is closed by the closure element and a drilling position in which the passage for soil material to enter the receiving space during drilling is open.

[0020] It is particularly preferred that the lower channel opening is closed in the drilling position of the closure element and that the lower channel opening is open in the closed position of the closure element. Thus, the passage and the lower channel opening can be actuated alternately by the closure element. This means that when drilling, the passage is open and the lower channel opening is closed simultaneously in the drilling position of the closure element, while in the closed position of the closure element, the passage to the receiving chamber is closed, and the lower channel opening remains open for flow and / or pressure equalization through the equalization channel.

[0021] The locking element can be designed in virtually any suitable manner. According to one embodiment of the invention, a particularly robust arrangement is achieved by designing the locking element as a rotating base that can be rotated between the locking position and the drilling position. In particular, one axis of rotation of the rotating base is coaxial with the central axis and drilling axis of the drilling tool.

[0022] In the drilling tool according to the invention, a cover, in particular a cover plate, is arranged on an upper region of the receiving chamber, which closes off the receiving chamber at the top and separates it from the upper channel opening. In the case of a drill bucket, this can be the upper housing cover of the box-like drill bucket. The cover can also be formed, in particular, on a drill auger, so that the receiving chamber of the at least one auger helix is ​​bounded at the top by the cover plate.

[0023] Above the cover plate is at least one upper channel opening. This ensures that, in the event of excessive filling of the collection chamber, excavated soil material cannot enter the upper collection opening.

[0024] The drilling tool is generally interchangeable and attached to a drill string or drive rod of a drilling rig. A particularly advantageous embodiment of the invention is characterized by the connection device having a Kelly connection. A Kelly connection comprises, in particular, a polygonal, especially a square, connection, wherein preferably a connecting sleeve with a polygonal or square receiving hole for a complementary connecting pin on the drill string is formed on the drilling tool. This polygonal plug connection achieves a rotationally fixed connection. Axial securing and connection can be achieved by means of one or more insertable transverse bolts.

[0025] A particularly advantageous embodiment of the invention consists in the drilling tool being designed as a drill bucket with a circumferential wall that encloses the receiving chamber like a housing. In the drill bucket according to the invention, the tubular central shaft extends centrally through the preferably cylindrically enclosed receiving chamber. The upper channel opening of the central compensating channel is located above the cover or the upper top plate of the drill bucket. A drill bucket can also be referred to as a box drill.

[0026] Alternatively, the drilling tool can be designed as a drill auger with at least one spiral helix arranged helically around the central shaft. The closing device is located on the underside of the drill auger, allowing the opening and closing of the at least one passage to the at least one spiral helix and thus to the receiving space between the helix turns.

[0027] The invention further comprises a drilling rig in which the drilling tool according to the invention is arranged. A drilling rig can, in particular, have a support unit, which preferably includes a chassis, especially a tracked chassis, and a superstructure rotatably mounted thereon. A mast, which is substantially vertical during operation, can preferably be attached to the superstructure via an adjustment mechanism. A rotary drive for rotating a drill string can be arranged on the support unit. The drilling tool according to the invention can be detachably attached to the underside of the drill string.

[0028] The drilling drive can preferably be moved and / or guided along the mast. The drilling rig is specifically designed for earth drilling and preferably for creating boreholes for foundation piles in the ground.

[0029] Furthermore, the invention comprises a method for creating a borehole in the ground, in particular for discontinuous drilling, wherein the drilling tool or drilling device according to the invention is used. The drilling tool removes soil material by rotating it, thus creating the borehole. In discontinuous drilling, a receiving chamber on the drilling tool is filled with the removed soil material and, after the opening is closed, withdrawn from the borehole for emptying.

[0030] The emptied drill bit is then returned to the borehole to perform another drilling step. This process is repeated until the desired final depth of the borehole is reached. The drilling can be carried out as cased drilling with a support casing or as uncased drilling.

[0031] One embodiment of the method according to the invention consists in opening the passage to the receiving chamber and closing the lower channel opening when soil material is removed during drilling. Thus, the removed soil material can be collected in the receiving chamber while the lower channel opening is simultaneously closed, preventing soil material from entering the channel opening.

[0032] Another advantageous embodiment of the invention is that, when the drilling tool is withdrawn, the passage to the receiving chamber is closed and the lower channel opening is opened. This ensures that no soil material can fall out of the receiving chamber through the passage when the drilling tool is withdrawn.

[0033] The opening of the compensating channel largely prevents the unwanted suction effect caused by the free channel opening during extraction. This allows for faster extraction of the drilling tool and thus more efficient borehole production. Furthermore, it reduces the risk of borehole wall collapse and soil failure.

[0034] According to a further development of the inventive method, it is advantageous that the compensating channel is opened when lowering the drilling tool into the borehole. The channel can be either closed or open. The open compensating channel during lowering also allows for a faster workflow and thus more efficient drilling.

[0035] The invention is further explained below with reference to a preferred embodiment, which is schematically illustrated in the accompanying drawings. The drawings show: Fig. 1 a first side view of a drilling tool according to the invention, which is designed as a drill auger; Fig. 2 a side view of the drilling tool of Fig. 1 in a view rotated by 90°; Fig. 3 a perspective view of the drilling tool of the Figure 1 and 2 Fig. 4 shows an enlarged partial cross-sectional view according to section AA of Fig. 1 ; and Fig. 5 a view of the drilling tool of the Figures 1 to 4 from underneath.

[0036] An embodiment of a drilling tool 10 according to the invention, which is designed as a drill screw with a screw helix 14, is described in the Figures 1 to 5The drilling tool 10 has a tubular central shank 30, which extends along a drilling or central axis 12. A soil removal device 20 is arranged at a lower end region of the drilling tool 10. The soil removal device 20 can have holders 22 on which detachably removal elements 24 are inserted. In the illustrated embodiment, the removal elements 24 are, by way of example, designed as round-shank chisels. Furthermore, a centering or pilot point 26 can be arranged at the lower end of the central shank 30.

[0037] At the lower end of the screw helix 14, a plate-shaped base 51 with a passage 28 can be formed. To form a closing device 50, a plate-shaped closing element 52 can be pivotably mounted about the central axis 12 directly below the base 51. By pivoting or rotating the closing element 52 relative to the fixed base 51, the passage 28 can be closed.

[0038] In the figures, the drilling tool 10 with the closing device 50 is shown in an open or drilling position in which the passage 28 is released or open. This allows excavated soil material from the removal device 20 to enter a receiving chamber 40 above it through the passage 28.

[0039] The drilling tool 10 can have a connecting device 45 with a receiving sleeve 47 at its upper end region, the connecting device 45 being designed as a Kelly connection in a known manner. A complementary connecting pin of a drill string of a drilling rig can be inserted into the receiving sleeve 47, which has a square hole, to create a rotationally fixed connection. An axially fixed connection can be formed by means of locking bolts (not shown) which can be inserted into transverse bores 49 in the receiving sleeve 47.

[0040] During drilling, the drilling tool 10 is driven to rotate around the central axis 12, whereby soil material removed by the removal device 20 can enter upwards through the passage 28 into a receiving chamber 40, which is formed by the free space between the turns of the screw helix 14 on the central shaft 30.

[0041] Within the tubular central shaft 30, a compensating channel 32 extends along the central axis 12, which at its lower end transitions via a side opening 33 into a downwardly directed opening channel section 35, which opens into a lower channel opening 34. In the illustrated embodiment, the lower channel opening 34 is closed and thus concealed by the closing element 52 in the open or drilled position.

[0042] At its upper end, the compensating channel 32 opens into an upper channel opening 36, which protrudes laterally from the central shaft 30, as can be clearly seen in Fig. 2 shown.

[0043] The receiving chamber 40 on the worm gear 14 can be closed off at the top by a plate-shaped cover 42, which can be held and stiffened by means of stiffening plates 43 at the upper end of the central shaft 30 or at the closing device 50.

[0044] During drilling, the receiving chamber 40 fills with excavated soil material, which enters the receiving chamber 40 from the excavation device 20 through the passage 28. Fig. 5 The screw helix 14 above it is visible through the open passage 28. After the receiving chamber 40 is filled, the plate-shaped closing element 52, which can also be referred to as a rotating base, can be rotated relative to the base 51 by a rotational movement in the opposite direction, thereby closing the passage 28. Simultaneously, the closing element 52 can release the lower channel opening 34, so that the compensating channel 32 is open and extends from the lower area of ​​the drilling tool 10 below the closing device 50 to the upper channel opening 36 above the cover 42.

[0045] The filled drill bit 10 can now be pulled vertically out of a borehole, with the closed sealing device 50 ensuring that excavated soil material from the receiving chamber 40 cannot fall back into the borehole. At the same time, the open compensation channel 32, which runs largely along the central shaft 30, ensures that no or only a slight negative pressure can develop between the underside and the top of the drill bit 10 during withdrawal. This applies particularly even when the drill bit 10 has an outer diameter D, as shown in Fig. 5 The indicated diameter largely corresponds to a bore. In this state, the drilling tool 10 can be gently and quickly withdrawn from the borehole.

[0046] Outside the borehole, the drilling tool 10 can be emptied of the soil material and then reinserted into the borehole for a new drilling step.

Claims

1. Drilling tool, in particular for discontinuous earth drilling, with - a ground removal means (20) which is arranged in a lower region of the drilling tool (10) and designed for removing ground material, - a receiving space (40) which is designed for receiving the removed ground material above the ground removal means (20) on the drilling tool (10), - at least one passageway (28) which is designed for the passage of the removed ground material from the ground removal means (20) into the receiving space during drilling, - a closure means (50) for closing the at least one passageway (28) during withdrawal of the drilling tool (10) from the borehole and - a connecting means (45) located in an upper region of the drilling tool (10) for releasable connecting with a drill rod, - wherein a tubular central shaft (30) is designed with a compensating channel (32) which extends from at least one lower channel opening (34) which is arranged below or on the closure means (50) up to at least one upper channel opening (36) which is arranged above the receiving space (40), wherein the compensating channel (32) is designed for the flowthrough of a medium between the lower region and the upper region of the drilling tool (10) during withdrawal and / or lowering of the drilling tool (10) in the borehole, characterized in that - in an upper region of the receiving space (40) a cover (42), in particular a cover plate, is arranged which closes off the receiving space (40) in the upward direction and separates it from the upper channel opening (36).

2. Drilling tool according to claim 1, characterized in that the lower channel opening (34) and / or the upper channel opening (36) is closable.

3. Drilling tool according to claim 1 or 2, characterized in that the closure means (50) for closing the passageway (28) to the receiving space (40) is also designed for closing / opening the lower channel opening (34).

4. Drilling tool according to any one of claims 1 to 3, characterized in that the closure means (50) has a closure element (52) which is adjustable between a closure position, in which the passageway (28) to the receiving space (40) is closed by the closure element (52), and a drilling position, in which the passageway (28) is open for the passage of ground material into the receiving space (40) during drilling.

5. Drilling tool according to claim 4, characterized in that in the drilling position of the closure element (52) the lower channel opening (34) is closed and in that in the closure position of the closure element (52) the lower channel opening (34) is open.

6. Drilling tool according to claim 4 or 5, characterized in that the closure element (52) is designed as a rotary bottom which can be rotated between the closure position and the drilling position.

7. Drilling tool according to any one of claims 1 to 6, characterized in that the connecting means (45) has a Kelly connection.

8. Drilling tool according to any one of claims 1 to 7, characterized in that the drilling tool (10) is designed as a drilling bucket with a circumferential wall which encloses the receiving space (40) in a housing-like manner.

9. Drilling tool according to any one of claims 1 to 7, characterized in that the drilling tool (10) is designed as a drilling auger with at least one auger flight (14) that is arranged helically around the central shaft (30).

10. Drilling apparatus, characterized in that a drilling tool (10) according to any one of claims 1 to 9 is arranged.

11. Method for producing a bore in the ground, in particular for discontinuous drilling, characterized in that a drilling tool (10) according to any one of claims 1 to 9 or a drilling apparatus according to claim 10 is used.

12. Method according to claim 11, characterized in that when removing ground material during drilling the passageway (28) to the receiving space (40) is opened and the lower channel opening (34) is closed.

13. Method according to claim 11 or 12, characterized in that for withdrawal of the drilling tool (10) the passageway (28) to the receiving space (40) is closed and the lower channel opening (34) is opened.

14. Method according to any one of claims 11 to 13, characterized in that for the lowering of the drilling tool (10) into the borehole the compensating channel (32) is opened.