Ground processing tool and a method for creating a borehole in the ground

Abstract

The invention relates to a ground processing tool and a method for creating a borehole in the ground, wherein ground material is removed by the ground processing tool and blended with a fluid in the created borehole to form a suspension, which is suctioned away via at least one opening in the at least one mixing blade and via the conducting channel in the central shaft.

Claims

1. A ground processing tool having a central shaft including a conducting channel built therein, the ground processing tool having at least one mixing blade attached to the central shaft and extending radially outward, wherein the at least one mixing blade comprises an inner cavity, the inner cavity communicates with the conducting channel in the central shaft, an outside of the mixing blade comprises at least one opening to the inner cavity, a removal apparatus is arranged on a lower side of the ground processing tool and is configured for removing ground material, a ring shaped circumferential wall is mounted on the central shaft and encircles a mixing area in which the at least one mixing blade is arranged, and a conveyor configured to convey the removed ground material is arranged between the removal apparatus and the at least one mixing blade.

2. The ground processing tool according to claim 1, wherein the circumferential wall includes an upper deck area that includes a hood-like mixing bell formed therein.

3. The ground processing tool according to claim 1 wherein the ring shaped circumferential wall is configured to be rotatable with respect to the central shaft.

4. The ground processing tool according to claim 1, further comprising multiple mixing blades arranged on the central shaft.

5. The ground processing tool according to claim 1, wherein at least one mixing element is attached to an inner side of the ring shaped circumferential wall.

6. The ground processing tool according to claim 1, further comprising a connecting apparatus for a joint connection with a suction apparatus provided in an upper area of the central shaft.

7. The ground processing tool according to claim 1, further comprising strut-shaped mixing elements arranged at the ring shaped circumferential wall.

8. A drilling device for earth and rock drilling, comprising the ground processing tool according to claim 1.

9. The drilling device according to claim 8, further comprising a suction pump configured to suction away ground material through the conducting channel in the central shaft via the at least one opening in the mixing blade.

10. A method for creating a borehole in the ground using a ground processing tool according to claim 1, the method comprising: removing ground material with the ground processing tool; blending the removed ground material with a fluid in the created borehole to form a suspension, and suctioning the suspension away via the at least one opening in the at least one mixing blade and via the conducting channel in the central shaft.

11. The method according to claim 10, further comprising: discharging the suspension from the borehole.

Description

(1) The invention will be described hereinafter by way of preferential embodiments, which are schematically depicted in the drawings. Shown in the drawings are:

(2) FIG. 1 a schematic cross-section view through a ground processing tool according to the invention;

(3) FIG. 2 an overhead view of the ground processing tool according to FIG. 1;

(4) FIG. 3 a perspective view of the ground processing tool shown in FIG. 1 and FIG. 2;

(5) FIG. 4 an overhead view of a further ground processing tool according to the invention;

(6) FIG. 5 a perspective view of the ground processing tool shown in FIG. 4;

(7) FIG. 6 an overhead view of a third ground processing tool according to the invention; and

(8) FIG. 7 a perspective view of the ground processing tool shown in FIG. 6.

(9) A ground processing tool 10 according to the invention as shown in FIG. 1 features a tube-shaped central shaft 12, at the lower end of which a centering spike 76 is arranged. Removal means 70 starts at the centering spike 76 and extends upward in a helical shape along the central shaft 12. Flat teeth 72 having cutting edges are, in this case, arranged on the outer edge of a helical drill, which transitions into conveying means 80 for the upward transport of the removed ground material. The removed ground material 80 is conveyed by means of the conveying means into a mixing area in the central area of the central shaft 12. Flat mixing blades 20 on the central shaft 12 projecting in a radial direction and a single box-shaped mixing blade 30 are arranged in this mixing area.

(10) As is evident from FIGS. 2 and 3 in particular, the box-shaped mixing blade 30 features an almost rectangular, hollow suction box 32. Arranged on the top thereof are five circular openings 34 for suctioning the suspension away from the mixing area. An arrow-like frontal area 36, onto which wear plates 38 are attached, is arranged on the forward-facing (in the direction of rotation) side of the box-shaped mixing blade 30.

(11) The inner cavity 32a of the suction box of the box-shaped mixing blade 30 communicates with a central conducting canal 14, which is formed in the tube-shaped central shaft 12, via a passage (not depicted) through the central shaft 12.

(12) Arranged on an upper side of the central shaft 12 is a connecting means 60, which can be used to connect the central shaft 12 with additional drill pipes by way of a joint connection. An axially directed spline profile 62 used for transmitting torque via the drill pipe is furnished on the top exterior of the central shaft 12. This profile engages in a positive lock with a corresponding spline profile on an inner side of the attached drill pipe. In this manner, torque from a rotary drive in a drilling apparatus (not depicted) can be transmitted to the ground processing tool 10.

(13) In the central mixing area of the ground processing tool 10, the ground material removed by the removal apparatus 70 is blended with added fluid to form a suspension. The radially projecting mixing blades 20, 30 do not, in this case, serve a mixing purpose, but are rather used to further crush the removed ground material, which is thus able to be reliably suctioned away via the openings 34 along with the fluid by means of the vacuum created by a pump (not depicted). In order to improve the mixing and crushing effect, cutting plates 22 made of hard metal are welded to the flat, sword-shaped mixing blades 20, the front sides of which are slender. Furthermore, a recess 24 and a support plate 26 are arranged on each sword-shaped mixing blade 20, the result of which is enhancing the turbulence created and enhancing the mixing effect thereby.

(14) In order to further improve the mixing effect, the central mixing area on the central shaft 12 is covered by a bell-like mixing hood 40, which is only depicted in FIG. 1. The mixing hood 40 features a cylindrical, drum-shaped circumferential wall 42, which is open on the bottom and ends in an upper plate-shaped deck area 44 on the top. The top end of the deck area 44 encloses an axially directed sleeve bearing 46, which is rigidly connected to the deck area 44 by means of stiffening plates 48. Via the sleeve bearing 46, the mixing hood 40 is rotatably mounted on and in relation to the central shaft 12 via a sliding sleeve 49. Arranged on the inner side of the cylindrical circumferential wall 42 are strut-shaped mixing elements 50, which cause the shear forces within the mixing area to increase.

(15) The edges of the mixing surfaces can be furnished with pointed wear elements.

(16) A further ground processing tool 10 according to the invention, which is likewise constructed as a drilling tool, is depicted in FIGS. 4 and 5. For the sake of clarity, the bell-like mixing hood 40, which is constructed in the manner of the previous embodiment, has been left out. This second embodiment of a ground processing tool 10 according to the invention is constructed largely in the manner of the previously described ground processing tool 10 according to FIGS. 1 to 3, but in this case drill bits 74 with pointed eroding cutters are provided as removal means 70 instead of the flat teeth 72. The drill bits 74 are arranged in corresponding drill bit fastenings along the free edge of the helical conveying means 80, the diameter of which gradually increases in going from the centering spike 76 to the maximum outer diameter above. In this embodiment according to FIGS. 4 and 5, the centering spike 76 is likewise constructed to have drill bits 74. A particularly vivid representation of the box-shaped mixing element 30 with the rectangular suction box 32 is made in the illustration according to FIG. 5. Arranged on the top thereof are openings 34 for suctioning away the suspension formed by the fluid and the crushed ground material.

(17) A particularly compact ground processing tool 10 according to the invention is shown in FIGS. 6 and 7, in which context the bell-like mixing hood 40 is likewise left out for the sake of clarity. The ground processing tool 10 according to FIGS. 6 and 7 differs from the previous ground processing tools in that the removal means 70 used for removing the ground materials is constructed essentially as a cutting edge running in a radial direction. In this case, the cutting edge is constructed as a large number of flat teeth 72 protruding in a circumferential direction. The adjoining surface is designed as a short helical segment forming a conveying means 80. For centering, a centering spike 76 is provided which conforms with the first embodiment according to FIGS. 1 to 3.

(18) All variations of the ground processing tool 10 according to the invention can be used in a conventional drilling tool having an undercarriage, an upper structure, and a mast having a top drive, and particularly used in Flydrill systems and onshore and offshore drilling systems. The ground processing tool is attached at the bottom of a drill string, which is driven by the drive in a rotary direction and can be moved up and down in an axial direction. The ground material is removed via a feed opening (not depicted here) and blended with a fluid in the mixing area beneath the mixing hood 40 by means of the rotating mixing blades 20, 30. By means of the mixing blades 20, 30, the removed ground material is crushed yet further so that the suspension produced is suctioned away via the openings 34 in the box-shaped mixing blade 30 and via the conducting channel 14 to be conducted upward and out of the borehole. The outer diameter of the mixing hood 40 essentially conforms with the bored diameter of the borehole being created by means of the removal means 70.

(19) The circular deck area 44 of the mixing hood 40 separates the mixing area from the borehole area thereabove. In this area, the borehole can be backfilled with a supporting fluid or a supporting suspension. It is ensured by means of the mixing hood that any undesired mixing between the supporting fluid or the supporting suspension and the removed ground material is avoided in the mixing area beneath the mixing hood 40.

(20) After the borehole has been sunk and the removed ground material thus conveyed, the drilling tool can be removed from the borehole. The supporting fluid can, in this case, be recovered while the borehole is being backfilled with a hardenable suspension. This can be hardened into a bored pile in the ground.