EP2133507A1 - Drilling device and drilling method - Google Patents

Abstract

The device (10) has a drilling element (20) rotatably driven by a drilling drive (16) and moved along rods (12). The drilling element includes an endless screwing drill (22) and an extension (30), where the endless screwing drill is arranged below the drilling drive, and the extension is connected with the endless screwing drill and extends upwards by the drilling drive. A displacement head (40) is arranged between the extension and endless screwing drill, where the extension is formed of a kelly bar with a drive block (32) at an outer side of the drilling element. Independent claims are also included for the following: (1) a drilling method for creating a borehole (2) a method for manufacturing a foundation element.

Description

The invention relates to a drilling device with a mast, a drill drive displaceably mounted thereon and a drilling element which is rotationally driven by the drill drive and movable along the mast, wherein the drilling element has an endless screw drill, which is arranged below the drill drive, and an extension which is connected to the endless screw drill and extends up through the drill drive.

Furthermore, the invention relates to a drilling method in which a drilling element is rotationally driven by means of a drill drive and moved along a mast, wherein the drilling element has an endless screw drill, which is arranged below the drill drive, and an extension which is connected to the endless screw drill and after extends up through the drill drive.

For the preparation of boreholes and in particular for the production of foundation piles, the use of so-called endless screw drills has long been known. In an endless screw drill, a drill spiral is arranged along the entire length of the drill rod, through which excavated soil material is conveyed by the rotational movement out of the borehole out to the surface. In this case, an endless screw drill is driven by a drill drive through which the endless screw drill is also moved in the drilling direction along a usually vertically erected mast. In this known method, the hole depth is limited by the length of the endless auger and the height of the mast.

To increase the borehole depth over the mast length or the length of the endless screw auger, it is out of the DE 601 02 255 T2 or the EP 1 614 853 B1 known to arrange at the top of the endless screw auger an extension rod which extends through the drill drive upwards. The depth of the borehole can thus be increased by about the length of the extension rod.

Functionally, however, no conveyor coil can be arranged on the extension rod. When drilling down a borehole beyond the length of the endless screw auger, therefore, the excavated soil material can no longer be conveyed through the conveyor filaments to the surface. This soil material thus accumulates in the borehole above the endless screw auger in the region of the extension rod. This can lead to an undesirable compression or blocking of the borehole, which makes it difficult to subsequently pull the boring element out of the borehole. In addition, in this area, the wall of the well can be disturbed, which can adversely affect the production of a foundation element in the well by filling with a filler. To prevent this, the drilling element must be pulled intermittently out of the borehole to remove soil material. This is time consuming.

The invention has for its object to provide a drilling apparatus and a drilling method with which boreholes can be produced by means of endless screw augers also over the length of the endless screw auger out efficiently and in good quality.

The object is achieved according to the invention by a drilling apparatus having the features of claim 1 and by a drilling method having the features of claim 11. Preferred embodiments are given in the respective dependent claims.

The drilling device according to the invention is characterized in that a displacer head is arranged between the endless screw auger and the extension.

When drilling down the borehole beyond the length of the endless screw auger, the upwardly conveyed soil material is displaced laterally into the borehole wall directly above the endless auger borer by the displacer head. Thus, no soil material can accumulate within the wellbore and lead to a blockage. Rather, the soil material is laterally displaced by the displacer head, wherein the borehole wall is compressed in a positive manner and additionally stabilized. This improves the stability and quality of the borehole and actively counteracts penetration of the borehole. In this way, with the boring device according to the invention over the length of the endless screw auger out the hole can be sunk in one go, until the end of the extension is reached. This significantly speeds up the creation of a wellbore with greater depths and also reduces the amount of excavation to be removed.

In principle, the extension can be designed as desired. In particular, the extension may be a telescopic rod or a rod composed of several segments. It is particularly preferred according to the invention that the extension is designed as a Kelly bar with entrainment strips on its outer side. The entrainment on the outside of the usually one-piece rod are in operative connection with corresponding drivers of a driven device of the drill drive to transmit torque from the drill drive to the extension. The entrainment strips are arranged parallel to the drilling axis, so that they allow axial displaceability through the annular drive drill. For the transmission of axial forces from the drill drive to the extension also so-called locking pockets can be provided with transversely directed strip portions.

In order to achieve particularly large drilling depths, it is inventively that the length of the endless screw auger corresponds approximately to the length of the mast or a maximum travel of the drill drive. In this way, first the maximum stroke of the drill drive, which is displaceable along the mast, be exploited. In this way, first, a wellbore having a depth corresponding to the length of the endless screwdriver can be efficiently created.

For the creation of a foundation element, it is advantageous according to the invention that the endless screw drill and / or the extension has a hollow core tube. About the hollow core tube so contents, in particular a curable suspension, such as concrete, can be introduced immediately after drilling the hole through the drilling element. For this purpose, one or more outlet openings are provided at the lower end of the endless screw auger. Thus, with the retraction of the endless auger from the borehole at the same time the borehole be filled from below.

Various displacement heads can be used on the drilling element according to the invention. Thus, rotationally symmetrical displacement heads, eccentric displacement heads or other displacer heads between the extension and the endless screw drill can be used for the drilling axis.

It is particularly preferred according to the invention that the displacer head has a cylindrical displacer portion, whose diameter corresponds approximately to the bore diameter. The bore diameter is determined by the outer diameter of the drill helices on the endless screw drill or by corresponding radial cutting edges at the lower end of the endless screw auger. The displacer section may be slightly smaller or larger than this drill diameter, depending on the soil properties. An equal diameter is advantageous because it facilitates both retraction of the displacer head into the wellbore and extraction of the auger bit from the wellbore.

According to the invention, it is advantageous that the displacer head has a lower cone section, the diameter of which widens upwards from the diameter of a center tube of the endless screw auger to the diameter of the displacer section. In this way, a gradual incorporation of the promoted up to the displacer head soil material can be achieved in the borehole wall. Also, the insertion of the displacer head is facilitated in the borehole.

This is further improved according to the invention in that a lower helix is arranged on the lower cone section, through which soil material can be conveyed upwards to the displacer section during drilling. This lower helix thus extends on the conical outer surface of the displacer section and has the same conveying direction of the conveying helix of the endless screw auger.

In addition, it is according to the invention that the displacer head has an upper cone section whose diameter tapers from the diameter of the displacer section upwards for extension. This arrangement allows that even from the top up the displacer falling material can be passed into the displacement zone of the displacer.

This effect is further enhanced according to the invention in that an upper coil is arranged at the upper cone section, through which soil material can be conveyed downwards to the displacement section during drilling. Thus, this helix has a reverse pitch compared to the helical auger helix or helix helix at the bottom cone section. The upper coil actively promotes falling from above soil material of the zone of the displacer section.

A preferred embodiment of the invention further consists in that the displacer section and / or at least one of the cone sections are covered with displacer elements. The displacers may be welded bars or arc segment-shaped elements which enhance the impressing or incorporation of the soil material into the borehole wall. At the same time, the displacement elements can serve as wear parts, which are readily interchangeable with heavy processing.

The drilling method according to the invention is characterized in that in a first drilling step up to a first drilling depth, which corresponds to the length of the endless screw drill, soil material is conveyed to the surface by the endless screw drill, and that in a second drilling step from the first drilling depth of the endless screw drill drilling material Displacer is supplied through which soil material is displaced into a borehole wall.

This method according to the invention achieves the above-described advantages in terms of drilling down the borehole over the length of the endless screw auger, stabilizing the borehole wall and avoiding excavation. The wellbore can be intermittently created in one go or in multiple steps using this drilling method, with the drill bit withdrawn at certain time or depth sections. As a result, a particularly good stabilization of the borehole wall can be achieved by repeatedly traversing the borehole wall with the displacer head.

For producing a foundation element, it is preferred according to the invention for filling material to be introduced into the borehole after the final drilling depth has been reached, which forms the foundation element. The filler may be a dry material, such as sand, lime or the like or a curable suspension, in particular a concrete mass. The filler material is preferably introduced through a central core tube of the endless screw auger into the wellbore.

Fig. 1

eine schematische Seitenansicht einer erfindungsgemäßen Bohrvorrichtung zu Beginn des erfindungsgemäßen Bohrverfahrens;

Fig. 2

eine schematische Seitenansicht der Bohrvorrichtung von Fig. 1 bei Abschluss des ersten Bohrschrittes;

Fig. 3

eine schematische Seitenansicht der Vorrichtung von Fig. 1 und Fig. 2 im zweiten Bohrschritt;

Fig. 4

eine schematische Teildarstellung der erfindungsgemäßen Bohrvorrichtung während des ersten Bohrschrittes; und

Fig. 5

eine schematische Teilansicht der erfindungsgemäßen Bohrvorrichtung während des zweiten Bohrschrittes.

The invention will be further elucidated on the basis of preferred exemplary embodiments, which are illustrated schematically in the attached drawings. In the drawings show:

Fig. 1

a schematic side view of a drilling device according to the invention at the beginning of the drilling method according to the invention;

Fig. 2

a schematic side view of the drilling device of Fig. 1 upon completion of the first drilling step;

Fig. 3

a schematic side view of the device of Fig. 1 and Fig. 2 in the second drilling step;

Fig. 4

a schematic partial view of the drilling device according to the invention during the first drilling step; and

Fig. 5

a schematic partial view of the drilling device according to the invention during the second drilling step.

In the FIGS. 1 to 3 an inventive drilling method is explained together with a drilling device 10 according to the invention. The drilling device 10 has according to Fig. 1 an approximately vertically arranged mast 12 which is pivotally mounted on a carrier device 14 via an adjusting mechanism 13. The carrier device 14 is formed in the present embodiment as a tracked vehicle with a rotatable uppercarriage.

Along the mast 12, a carriage 18 is slidably mounted in a known manner via a cable mechanism. An annular drilling drive 16 for driving the rod-shaped drilling element 20 is provided on the carriage 18. The drilling element 20 comprises in its lower region a so-called endless screw drill 22, which is formed from a center tube or a core tube 24, at whose Outside a conveyor coil 26 extends over almost the entire length. At the lower end of the endless screw drill 22, a cutting device 28 is formed in a known manner, which removes soil material.

The length of the endless screw drill 22 is adapted to the length of the mast 12 and corresponds approximately to the length of the mast 12. In the illustrated embodiment, the mast has a length of about 20 m, while the length of the endless screw drill is about 15 m. The slightly shorter length of the endless screw drill 22 relative to the length of the mast 12 is essentially due to the size and extent of the auger drive 16 with the carriage 18.

At the upper end of the endless screw drill 22 below the auger drive 16, a displacer 40 is connected, which hereinafter in connection with the FIGS. 4 and 5 will be explained in more detail. Following the displacer head 40, a rod-shaped extension 30 is attached, which extends from the arranged below the auger drive 16 displacer 40 through the annular auger drive 16 therethrough upwards. On the outside of the extension 30 longitudinally extending entrainment strips 32 are arranged in the manner of a Kelly bar in the drilling direction. About this Mitnehmerleisten 32, the torque of the drill drive 16 can be transferred to the extension 30 and thus the drilling element 20 in total. The entrainment 32 further allow in a known manner an axial displaceability of the extension 30 relative to the drill drive 16 with simultaneous torque transmission.

In a first drilling step according to Fig. 2 a borehole 6 is lowered until the upper end of the endless screw borer 22 is reached. During this first drilling step, soil material worked off by the cutting device 28 is conveyed upwards out of the borehole 6 by the conveying spirals 26. At the end of the first drilling step, the drill drive 16 is moved to a maximum, ie from its upper starting position according to FIG Fig. 1 in its lower end position at the bottom of the mast. In order to continue to drill down the borehole 6, the boring element 20 is now driven further downwards via the extension 30 when the boring drive 16 is now stationary. The propulsion in the drilling direction can be significantly effected by the weight of the drilling element 20 and the propelling action of the conveyor helices 26. The drill drive 16 but can alternatively be reset and the extension 30 actively proceed in the drilling direction.

In this second drilling section, the excavated soil material from the conveyor coils 26 of the endless screw 22 can no longer be conveyed to the surface. So that there is no blocking in the area of the bar-shaped extension 30, which has now been lowered into the borehole 6, this worked-out soil material is displaced laterally into the borehole wall in accordance with the invention by the displacer head 40. After completion of the second drilling step, in which the rod-shaped extension according to Fig. 3 moved into its lower end position, via a suspension port 34 at the upper end of the extension 30 via the hollow interior of the extension 30 and the core tube 24 a product in the wellbore 6 at the lower end of the endless screw 22 are introduced.

In Fig. 4 the drilling method according to the invention is shown during the first drilling step. In this case, a borehole 6 is introduced by the endless screw drill 22 into the bottom 2. Exhausted soil material 4 is conveyed from the borehole 6 through the conveyor coils 26 upwards to a surface 3. From here, the processed soil material 4 can be removed and removed in a known manner.

At the upper end of the central core tube 24 of the endless screw drill 22, a pipe connection 25 is arranged, to which the displacer head 40, not shown here, is non-rotatably coupled.

After completion of the first drilling step, when the maximum travel of the drill drive 16 is reached and the endless screw drill 22 is retracted with its entire length in the bottom 2, is according to Fig. 5 now upwardly promoted soil material 4 laterally incorporated by the displacer 40 in the borehole 7.

In the preferred exemplary embodiment, the displacement head 40 has an approximately central, cylindrical displacement section 42, on the outside of which strip-shaped displacement elements 44 are arranged. Below the displacer section 42, a lower cone section 46 is arranged, which on its outer side with a lower Wendel 48 is provided. The lower helix 48 serves to convey the processed soil material 4 into the region of the displacement section 42.

The reverse conical lower cone portion 46 is rotatably connected via the pipe joint 25 with the endless screw 22. In this case, the diameter of the lower cone section 46 widens continuously from the diameter of the core tube 24 to the diameter of the cylindrical displacement section 42.

In the reverse manner, an upper cone section 50 with an upper coil 52 is arranged above the displacement section 42. The upper coil 52 has an opposite conveying direction to the lower coil 48, so that in the usual direction of rotation of soil material from the upper coil 52 down to the central displacement section 42 is promoted.

The upper cone portion 50 has a regular conical shape, the diameter of which tapers uniformly from the diameter of the displacer portion 42 up to approximately the diameter of the rod-shaped extension 30. The rod-shaped extension 30 is rotatably connected via an upper pipe connection with the displacer 40.

Claims (12)

Drilling device with a mast (12), - A displaceably mounted thereto drill drive (16) and a drilling element (20) which is rotationally driven by the drill drive (16) and is movable along the mast (12), - wherein the drilling element (20) comprises an endless screw drill (22) disposed below the drill drive (16), and an extension (30) which is connected to the endless screw drill (22) and up through the drill drive (16) extends through, characterized,
in that a displacement head (40) is arranged between the endless screw drill (22) and the extension (30). Drilling device according to claim 1,
characterized,
in that the extension (30) is designed as a Kelly bar with entrainment strips (32) on its outer side. Drilling device according to claim 1 or 2,
characterized,
that the length of the endless screw drill (22) corresponds approximately to the length of the mast (12) or a maximum travel of the drill drive (16). Drilling device according to one of claims 1 to 3,
characterized,
in that the endless screw drill (22) and / or the extension (30) have a hollow core tube (24). Drilling device according to one of claims 1 to 4,
characterized,
in that the displacer head (40) has a cylindrical displacer section (42) whose diameter corresponds approximately to the drill diameter. Drilling device according to claim 5,
characterized,
in that the displacer head (40) has a lower cone section (46) whose diameter widens upwards from the diameter of a center tube of the endless screw auger (22) to the diameter of the displacer section (42). Drilling device according to claim 6,
characterized,
in that a lower coil (48) is arranged on the lower cone section (46), through which bottom material (4) can be conveyed during drilling upwards to the displacement section (42). Drilling device according to one of claims 5 to 7,
characterized,
in that the displacer head (40) has an upper cone section (50) whose diameter tapers from the diameter of the displacer section (42) upwards to the extension (30). Drilling device according to claim 8,
characterized,
in that an upper coil (52) is arranged on the upper cone section (50) through which drilling material (4) can be conveyed downwards to the displacement section (42) during drilling. Drilling device according to one of claims 5 to 9,
characterized,
in that the displacer section (42) and / or at least one of the cone sections (46, 50) is covered with displacement elements (44). Drilling method, in particular with a drilling device (10) according to one of claims 1 to 10,
in which a drilling element (20) is rotationally driven by means of a drilling drive (16) and moved along a mast (12), the drilling element (20) comprising an endless screw drill (22) disposed below the drilling drive (16) and an extension (30) connected to the endless screw drill (22) and extending upwardly through the drill drive (16),
characterized,
that in a first drilling step up to a first drilling depth which corresponds approximately to the length of the continuous screw auger (22) through which continuous screw auger (22) soil material (4) is conveyed to the surface (3), and
that in a second drilling step starting from the first drilling depth of the endless screw drill (22) soil material (4) is supplied to the displacer head (40), through which the soil material (4) in a borehole wall (7) is displaced. Method for producing a foundation element,
characterized,
that a borehole (6) is produced by the drilling method according to claim 11 and
that after reaching the final drilling depth in the borehole (6) filling material is introduced, which forms the foundation element.

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