EP1885997B1 - Method and device for drilling, particularly percussion or rotary percussion drilling, a hole in soil or rock material - Google Patents

Abstract

The invention relates to a method and device for drilling, particularly percussion or rotary percussion drilling, a hole in soil or rock material and for producing an anchoring. According to the invention, a drill bit (2) fastened to drilling rods (3) makes a drilled hole (1). A number of, in particular, wedge-shaped spreading elements (7) oriented contrary to the direction of drilling (6) are provided in a part joined to the drill bit (2). These spreading elements can be introduced into the wall of the drilled hole (1) after the drilled hole (1) is completed whereby making it possible to obtain a secure anchoring immediately after the drilled hole (1) has been completed.

Description

The present invention relates to a method for drilling, in particular percussion or rotary impact drilling, a hole in soil or rock material and fixing an anchor in the hole, wherein a borehole is formed by a drill bit mounted on a drill string. The invention further relates to a device for drilling, in particular percussion or rotary impact drilling, a hole in soil or rock material and for the production of an anchor, wherein a drill bit mounted on a drill string forms a borehole.

In connection with the production of a hole in soil or rock material and a subsequent determination of an anchorage or a lining in the borehole, it is for example from WO 98/21439 and the WO 98/58132 it is known to introduce a cladding tube into the wellbore during the drilling operation, such as impact or rotational impact drilling, whereupon after completion of the bore, if necessary, a portion of the drillcrown is removed from the well together with the drill string while the cladding tube remains in the wellbore so that subsequently is formed by filling with a hardening mass anchor in the borehole. According to the training according to WO 98/58132 the drill pipe can be formed on its outer circumference with additional ribs and grooves, so that when the drill pipe remains in the borehole and a subsequent backfilling a correspondingly good anchor effect can be achieved. To further improve the anchoring effect is for example from the AT-U 5644 known to bring the cladding tube by expanding its outer periphery in abutment against the inner wall of the borehole.

From the US-A 5,649,789 and the US-A 4,789,284 Formations of a drilling device or a self-drilling anchor are known, wherein the drilling element surrounds at least one expandable, dowel-like element, which is expandable particularly after completion of the bore in abutment against the borehole wall, wherein expandable portions are oriented or extend in the drilling direction. A determination is made by pressing against the borehole wall, while an anchoring effect in an impingement or force counter to the drilling direction in loose, surrounding material is not possible.

Alternatively, after making a well, it is known to remove the drilling tool with the drill string from the wellbore, after which a separate anchor or an anchor device is introduced into the wellbore, as for example from EP-B 0 241 451 , of the US-A 4,490,074 , of the DE-AS 21 05 888 , of the US-A 4,310,266 or the EP-A 0 875 663 has become known. A disadvantage of this known prior art is the fact that in a first step, the borehole must be prepared, whereupon after removal of the drilling tool together with the drill pipe in a further process step, the anchor device is introduced into the possibly a large length having borehole, which then by Removing the corresponding holding device with expansion of the outer diameter succeeds an investment in the borehole wall. It is immediately obvious that not only for the two separate steps a corresponding increased time is required, but that optionally a subsequent introduction of such an anchor device of great length is associated with difficulties. Furthermore, it can be assumed that a removal of the drilling device together with the drill pipe and a subsequent introduction of the anchoring device is feasible only in relatively solid soil or rock, which must be ensured that not, for example, during the drilling process or after removing the drill and before the final introduction of the anchoring device material breaks into the wellbore, so that the wellbore would be blocked, whereby an introduction of the anchor device is no longer possible.

The present invention therefore aims to develop a method and an apparatus of the type mentioned in that with a simplified design and reduced time immediately after completion of a well an anchorage to the inner wall of the well can be achieved.

To solve these problems, the method of the invention, starting from a method of the type mentioned above essentially characterized in that after completion of the well a plurality of spaced from the drill bit, oriented counter to the drilling direction, in particular wedge-shaped expansion elements in the wall of the drill bit trained wellbore is applied. Due to the fact that after completion of the borehole an anchoring takes place directly opposite to the drilling direction or oriented, in particular wedge-shaped spreading elements, the additional working step of a separate introduction can take place An anchoring in the finished wellbore be omitted after a previous removal of the drill pipe and the drilling tool, so that it can achieve a corresponding time savings. In addition, the method according to the invention can be applied regardless of the soil or rock material to be drilled, since an anchorage is made immediately after forming the borehole in the borehole, so that even with loose rock, in which optionally a break-in at least after removal of the Drilling tool and would be feared before introducing an anchor, no difficulties are to be feared as in subsequently produced anchors. By applying or exiting the counter to the drilling direction, in particular wedge-shaped spreading immediately occurs at least the tips of the spreading, which run counter to the drilling direction, so that a correspondingly good anchoring effect immediately after completion of the well can be achieved.

For a particularly simple deployment of the expansion elements after completion of the borehole is proposed according to a preferred embodiment that the deployment of the spreading is triggered by a rotational movement of the drill string against the direction of rotation for producing the borehole through the drill bit and / or made, and that a particular annular Expander element is mounted on the circumference of the drill string and is displaced in a rotational movement of the drill string in a direction opposite to a rotational movement in carrying out the drilling operation in the direction of the drill bit along the longitudinal direction of the drill string and cooperates with the expansion elements. It can thus in the usual way the production a borehole can be achieved by a percussion or rotary impact drilling by providing a specific direction of rotation during the drilling operation, and then after completion of the borehole a deployment of the spreading by a rotational movement of the drill string against the direction of rotation for producing the borehole triggered and / or made.

For a simple introduction of the spreading without obstruction of the drilling operation is provided according to a further preferred embodiment, that the spreading elements are biased during the drilling operation in the direction of the drill string.

To improve the anchoring effect and / or to support a proper entry of the spreading elements which run counter to the direction of drilling, In particular, have wedge-shaped tips, is proposed according to a further preferred embodiment, that during the leakage of the spreading and / or alternately with the exit movement of the same the drill string against the drilling direction towards the open end of the borehole is acted upon or withdrawn. By a simultaneous and / or alternating pulling or acting on the drill string and thus the spreading elements during the exit movement, the tips of the spreading occur deeper into the material, so that there is a corresponding support for anchoring effect.

After the spreading or emergence of the spreading an anchor element is formed on the remaining drill hole in the wellbore and the drill bit. If special requirements are made of the anchoring, it is proposed according to a further preferred embodiment that after completion of the borehole and exit or anchoring of the spreading the drill string is divided in particular in the region of the spreading and removed from the well and by an anchor element, in particular a Strand anchor is replaced, which is connected to the remaining in the borehole portion of the drill string, in particular screwed, is. By inventively provided subdivision of the drill string and thus the possibility of removing a portion is made possible after completion of the borehole and a leakage or anchoring of the spreading the drill pipe by a corresponding specialized anchoring element, for example, a strand anchor, which with the well in the remaining portion of the drill string and the drill bit connected accordingly, for example screwed.

To solve the problems initially posed a device of the type mentioned above is substantially characterized in that in a subsequent to the drill bit a plurality of particular wedge-shaped, counter to the drilling direction oriented expansion elements is provided, which after completion of the drill bit formed by the drill bit Boreholes are ausbringbar in the wall of the borehole. By emerging after completion of the borehole, in particular wedge-shaped and oriented counter to the drilling direction expansion elements can be directly secure anchoring achieve a corresponding time savings.

For a reliable and not disturbing the drilling introducing the expansion elements is proposed according to a further preferred embodiment, that the spreading elements acted upon during the drilling operation in the direction of the drill string, in particular by at least one bracket are biased.

For a reliable spreading of the spreading and for introducing a corresponding anchoring force or action is proposed according to a further preferred embodiment that a particular annular expansion element is mounted on the circumference of the drill string and in a rotational movement of the drill string in one to a rotary motion in carrying out the drilling operation opposite direction in the direction of the drill bit along the longitudinal direction of the drill string is displaced and cooperates with the wedge-shaped spreading elements, which pivotally connected to a particular with the drill string fixedly connected and arranged between the expansion element and the drill bit bearing element.

As indicated above, the impact or rotary impact drilling is carried out by a movement of the drill bit of the drill string in a predetermined direction of rotation, wherein the direction of rotation of the drill string is reversed for spreading the spreading. In order to avoid an impairment of the drilling process and to be able to deploy the expansion elements in a reversal of the rotational movement of the drill string after completion of the well, it is also proposed that at least one spring element is provided on the expansion element, which during the drilling process in a recess or depression on the circumference of the expansion element is receivable and cooperates upon reversal of the direction of rotation with at least one facing the interior of the device profiling on at least one expansion element to prevent the expansion element from rotating and cause by providing a threaded connection to a displacement along the longitudinal direction, as a further preferred embodiment of the device according to the invention corresponds. There is thus the drilling operation to the effect that the expansion element moves in the manner of a ratchet relative to the expansion elements, while reversing the direction of rotation, the spring element cooperates directly with at least one profiling on at least one spreading elements to prevent the expansion element from rotating, wherein Providing a correspondingly extending threaded connection, a displacement of the expansion element takes place in the longitudinal direction of the drill string and in particular in the direction of the drill bit, in order to allow the wedge-shaped spreading elements, which run counter to the drilling direction, to emerge.

To achieve a corresponding flushing effect even when providing the expansion element surrounding the drill string, it is proposed according to a further preferred embodiment that at least one flushing channel extending in the longitudinal direction of the device be provided in the expansion element.

To achieve a uniform anchoring effect over the region of the borehole is also provided that the expandable expansion elements are arranged distributed substantially uniformly over the circumference of the drill string, as corresponds to a further preferred embodiment of the device according to the invention. As a result, uniformly high anchoring forces can be introduced over the circumference of the borehole and the drill pipe into the surrounding soil or rock material.

In addition to such homogenization of the forces to be introduced over the circumference of the device according to the invention can be provided to further increase the anchoring forces to be introduced that a plurality of expandable expansion elements is provided at different distances from the drill bit on the circumference of the drill string, as a further preferred embodiment of the invention Device corresponds. By such, at different distances from the drill bit arranged, expandable expansion elements can be over a greater length, in particular in the front region of the device according to the invention achieve a correspondingly secure anchoring when expanding the expandable expansion elements, so that even with possibly loose rock at least some of the spreading elements arranged at different distances from the drill bit, which are additionally distributed over the circumference of the device according to the invention, can ensure a secure and reliable anchoring.

For further homogenization of the anchoring effect over the circumference as well as a longitudinal extent of the device according to the invention is proposed according to a further preferred embodiment that arranged at different distances from the drill bit spreading elements in the circumferential direction of the drill string offset from each other.

To simplify the Ausbringvorgangs of the individual spreading elements, which are arranged according to a preferred embodiment at different distances from the top of the borehole or the drill bit, is proposed according to a further preferred embodiment that arranged at different distances from the drill bit spreading with a common, along interacting with the drill string displaceable arranged expansion element.

Instead of the formation of an anchor through the drill pipe remaining in the well and the drill bit is proposed according to a further preferred embodiment, that the drill string is divisible in particular in the region of the expansion elements in sections and an anchor element, in particular a screw head of a Litzenankers, with the remaining in the well and connected to the drill bit portion of the drill string is connectable. This will make it possible after completion of the borehole and an anchoring or emergence of the spreading on a special anchoring action tuned anchor elements, in particular a strand anchor to bring, which in a particularly simple manner with the remaining portion of the drill pipe in the wellbore is connectable.

In order to achieve a corresponding flushing action is also preferably provided that the drill string is formed in a conventional manner in the interior with a flushing channel. such a flushing channel can be used not only for introducing flushing fluid during the drilling process, but optionally also for introducing a hardening material, which is introduced in the region of the tip and / or the region of the expansion elements.

• Fig. 1 einen Teilschnitt durch eine erste Ausführungsform einer erfindungsgemäßen Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens;
• Fig. 2 in einer zu Fig. 1 ähnlichen Darstellung einen Schnitt, wobei entgegen der Bohrrichtung verlaufende, keilförmige Spreizelemente in die Bohrlochwand nach einer Fertigstellung der Bohrung eintreten;
• Fig. 3 einen Schnitt entlang der Linie III-III durch den Bereich der Spreizelemente sowie des Aufweitelements der erfindungsgemäßen Vorrichtung;
• Fig. 4 in einer zu Fig. 1 ähnlichen Darstellung einen Schnitt durch eine abgewandelte Ausführungsform einer erfindungsgemäßen Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens, wobei entlang der Längsrichtung der Vorrichtung eine Mehrzahl von Spreizelementen vorgesehen ist;
• Fig. 5 einen Teilschnitt ähnlich zu Fig. 4, wobei wenigstens ein Spreizelement in die Wand des umgebenden Bohrlochs ausgetreten ist;
• Fig. 6 in einer zu Fig. 4 ähnlichen Darstellung einen Schnitt durch eine weitere abgewandelte Ausführungsform einer erfindungsgemäßen Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens, wobei das Bohrgestänge im Bereich der Spreizelemente unterteilt ausgebildet ist; und
• Fig. 7 in einer zu Fig. 5 ähnlichen Darstellung einen Teilschnitt der Ausführungsform gemäß Fig. 6, wobei der von der Bohrkrone abgewandte Teil des Bohrgestänges entfernt und durch ein Ankerelement, insbesondere einen Litzenanker, nach einem Austreten von wenigstens einem Spreizelement in die Wand des umgebenden Bohrlochs ersetzt ist.

The invention will be explained in more detail with reference to embodiments schematically illustrated in the accompanying drawings. In this show:

• Fig. 1 a partial section through a first embodiment of a device according to the invention for carrying out the method according to the invention;
• Fig. 2 in one too Fig. 1 similar representation of a section, wherein opposite to the drilling direction, wedge-shaped spreading occur in the borehole wall after completion of the bore;
• Fig. 3 a section along the line III-III through the region of the spreading and the expansion element of the device according to the invention;
• Fig. 4 in one too Fig. 1 a similar representation of a section through a modified embodiment of a device according to the invention for carrying out the method according to the invention, wherein along the longitudinal direction the device is provided with a plurality of spreading elements;
• Fig. 5 a partial section similar to Fig. 4 wherein at least one expansion element has leaked into the wall of the surrounding borehole;
• Fig. 6 in one too Fig. 4 a similar representation of a section through a further modified embodiment of a device according to the invention for carrying out the method according to the invention, wherein the drill string is formed divided in the region of the spreading elements; and
• Fig. 7 in one too Fig. 5 similar representation of a partial section of the embodiment according to Fig. 6 wherein the remote from the drill bit portion of the drill string is removed and replaced by an anchor element, in particular a strand anchor, after leakage of at least one expansion element in the wall of the surrounding wellbore.

In Fig. 1 and 2 1 is a wall of a borehole, which is produced by a drill bit indicated schematically by 2, wherein the drill bit 2 is mounted on a drill pipe designated 3, wherein in a known manner by means not shown a shock and rotational stress of the drill string. 3 for the production of the borehole 1 via provided outside of the borehole 1 drive means. The drill pipe 3 is also provided with a drilling channel 4 indicated schematically for rinsing the drill bit 2 and optionally for discharging the degraded material during the drilling process.

At a distance from the drill bit 2, a fixed nut 5 is provided on the drill string 3, followed by a plurality of in an opposite direction of drilling. 6 extending widening direction, wedge-shaped spreading elements 7 are arranged distributed along the circumference of the drill pipe 3. The spreading elements 7 are during the in Fig. 1 illustrated drilling operation by a bracket or clamping bracket 8 is acted upon in a position in which the spreading elements 7 are within the defined by the drill bit 2, clear cross-section of the borehole 1 so as not to affect the drilling process.

After completion of the well 1, wherein the drill bit 2, for example, counterclockwise in the direction of arrow 9 in Fig. 3 and thus is rotated counterclockwise, there is a reversal of the direction of rotation of the drill pipe 3 against the drilling direction 9, so that a between at least one wedge-shaped expansion element 7 and a drill pipe 3 mounted expansion element 10 provided spring element 11 from a corresponding recess or recess 12 on the circumference of Expander element 10 exits and interacts with a profiling 13 on the inner circumference of the expansion element 7, so that upon reversal of the direction of rotation of the drill string 3 and provision of a corresponding thread formation on the outer circumference of the drill pipe 3 and the expander 10, the expander 10 in the direction of the arrow 6 in the direction moves to the drill bit 2 or relocated, as indicated by an arrow 14 in Fig. 2 is indicated. By the displacement of the expander 10 in the direction of the arrow 14 and in the drilling direction 6, a pivoting of the spreading 7 takes place in the in Fig. 2 shown position, wherein in each case the tips 15 of the spreading elements 7 enter into the surrounding borehole wall 1 and thus anchor the anchor formed by the drill pipe 3 and the drill bit 2 safely in the produced wellbore 1.

To assist or improve the anchoring effect can be provided hiebei that either simultaneously with the movement of the expansion element 10 and thus the spreading of the spreading 7 in the surrounding borehole wall 1 a tensile stress on the drill string 3 against the arrows 6 and 14 is made so that the tips 15 of the wedge-shaped spreading elements 7 dig deep or deeper into the surrounding borehole wall 1 or deep.

For a proper removal of the degraded material or to achieve a corresponding flushing effect is also in Fig. 1 and 2 at least one flushing channel 16 indicated in the expansion element 10.

How out Fig. 1 to 3 can be seen, a plurality of wedge-shaped spreading elements 7 along the circumference of the drill string 3 is arranged, wherein in the in Fig. 1 to 3 embodiment illustrated four segment-like wedge-shaped spreading elements 7 are provided to achieve a corresponding anchoring effect. The spreading elements 7 are hiebei correspondingly mounted on the biasing bracket 8 or hinged to a likewise provided on the drill pipe 3 bearing element.

According to the anchoring effect to be achieved and / or the nature of the surrounding soil or rock material, the spreading elements 7 are arranged in their length, training, prestressing force and number corresponding to the circumference of the drill pipe 3.

In Fig. 1 In addition, a locking pin 20 is provided behind the expansion element 10 to this against accidental Move or lose to secure. The extent of the longitudinal displacement of the expansion element 10 during the application of the wedge-shaped spreading elements 7 can hiebei from the in Fig. 2 apparent distance between the locking pin 20 and facing away from the drill bit 2 end of the expander 10 recognize.

At the in 4 and 5 illustrated embodiment, in turn, a drill bit 2 for producing the borehole 1 is mounted on a drill string designated 3.

While in the embodiment according to Fig. 1 to 3 the wedge-shaped spreading elements 7 are provided substantially side by side on the circumference of the drill string 3, is provided in this embodiment, that at a different distance from the drill bit 2 a plurality of 17 and 18 designated spreading elements is arranged.

Similar to the previous embodiment, drilling takes place, for example, by a movement of the drill pipe 3 in the counterclockwise direction, while completion of the borehole 1 by reversing the direction of rotation of the drill string 3, a deployment or extension of the expansion elements 17 and 18 again takes place in that by a corresponding engagement of a spring element 12 is a displacement or displacement of the in turn designated 10 expansion element in the direction of the drill bit 2, as shown in Fig. 5 is indicated, so that enter through corresponding ramp-like portions 19 of the expansion element 10 arranged at different distances from the drill bit 2 spreading 17 and 18 in the borehole wall 1. In addition to a different distance of the spreading elements 17 and 18 of the drill bit 2 can for a Be provided equalization of the anchoring effect beyond that the spreading elements 17 and 18 distributed and offset over the circumference of the drill pipe 3 are arranged, and this is in particular for spreading 17 and 18 of interest, which extends over a small portion or opening angle over the Extend the circumference of the drill string 3.

In the in 6 and 7 illustrated embodiment is similar to the embodiment according to 4 and 5 arranged at a different distance from the drill bit 2 a plurality of again with 17 and 18 designated spreading elements. Similarly as in the previous embodiment, drilling is again carried out by a movement of the drill string 3 in the counterclockwise direction, while after completion of the borehole 1 by reversing the drilling direction of the drill string 3, a spreading or exit of the expansion elements 17 and 18 again takes place in that by a corresponding engagement of the spring element 12, a displacement or displacement of the in turn designated 10 expansion element in the direction of the drill bit 2, as is made Fig. 7 is apparent. Similar to the embodiment according to 4 and 5 finds a common expansion element 10 for the plurality of longitudinally arranged expansion elements 17 and 18 use.

In the embodiment according to 6 and 7 it can be seen that the drill string 3 is divided into separable sections 3 'and 3 ", wherein a connection 23 between the sections 3' and 3" of the drill string, for example, can be achieved with a conical hexagonal guide.

After completion of the bore and leakage of at least some spreading elements, as in Fig. 7 is indicated, there is a separation of the drill string elements 3 'and 3 ", followed by a designated 21 screw head of a designated Litzenankers 22 is introduced and screwed into an internal thread of the hollow drill pipe or the remaining in the wellbore 1 portion 3' thereof Thus, after completion of the borehole 1 and correspondingly secure anchoring by an exit of the spreading elements 17 or 18 after a reversal of the direction of rotation of the drill pipe 3, as described in connection with the preceding embodiment, an example of the conditions of the surrounding soil or rock material tuned anchoring element, for example in the form of the strand anchor 22, after removal of the portion 3 "of the drill string 3 introduce and anchor securely. Such an approach can hiebei according to the choice of material of the introduced anchor 22 represent an alternative to other possible permanent anchor.

Claims (16)

1. A method for drilling, particularly percussion or rotary percussion drilling, a hole (1) in soil or rock material and fixing an anchorage in said hole (1), wherein a borehole is formed by a drill bit (2) mounted on a drill rod assembly (3), characterized in that, after the completion of the borehole (1), a plurality of, in particular, wedge-shaped spreading elements (7, 17, 18) arranged at a distance from the drill bit and oriented contrary to the drilling direction are extended into the wall of the borehole (1) formed by the drill bit (2).
2. A method according to claim 1, characterized in that the extension of the spreading elements (7, 17, 18) is initiated and/or effected by a rotational movement of the drill rod assembly (3) contrary to the direction of rotation for the production of the borehole (1) by the drill bit (2) and in that an, in particular, annular expansion element (10) is mounted about the periphery of the drill rod assembly (3) and, at a rotational movement of the drill rod assembly (3) in a direction contrary to a rotational movement (9) carried out during the performance of the drilling procedure, is displaced in the direction towards the drill bit (2) along the longitudinal direction of the drill rod assembly (3) and cooperates with the spreading elements (7, 17, 18).
3. A method according to claim 1 or 2, characterized in that the spreading elements (7, 17, 18) are prestressed in the direction towards the drill rod assembly (3) during the drilling procedure.
4. A method according to claim 1, 2 or 3, characterized in that, during the emergence of the spreading elements (7, 17, 18), and/or alternatingly with the emerging movement of the same, the drill rod assembly (3) is respectively powered or retracted in the direction towards the open end of the borehole (1), contrary to the drilling direction.
5. A method according to any one of claims 1 to 4, characterized in that, after the completion of the borehole (1) and emergence or anchoring of the spreading elements (7, 17, 18), the drill rod assembly (3) is subdivided, in particular, in the region of the spreading elements (7, 17, 18) and removed from the borehole (1) and replaced by an anchor element, in particular a cable strand anchor (22), which is connected, in particular screwed, with the drill rod assembly subportion remaining in the borehole (1).
6. A device for drilling, particularly percussion or rotary percussion drilling, a hole (1) in soil or rock material and for the production of an anchorage, wherein a borehole (1) is formed by a drill bit (2) mounted on a drill rod assembly (3), characterized in that, in a portion joining the drill bit (2), a plurality of, in particular, wedge-shaped spreading elements (7, 17, 18) oriented contrary to the drilling direction (6) are provided, which are extensible into the wall of the borehole (1) after the completion of the borehole (1) formed by the drill bit (2).
7. A device according to claim 6, characterized in that the spreading elements (7, 17, 18) are powered, particularly prestressed by at least one strap (8), in the direction towards the drill rod assembly (3) during the drilling procedure.
8. A device according to claim 6 or 7, characterized in that an, in particular, annular expansion element (10) is mounted about the periphery of the drill rod assembly (3) and, at a rotational movement of the drill rod assembly (3) in a direction contrary to a rotational movement (9) carried out during the performance of the drilling procedure, is displaceable in the direction towards the drill bit (2) along the longitudinal direction of the drill rod assembly (3) and cooperates with the wedge-shaped spreading elements (7, 17, 18), which are, in particular, pivotally articulated to a bearing element which is, in particular, fixedly connected to the drill rod assembly (3) and arranged between the expansion element (10) and the drill bit (2).
9. A device according to claim 8, characterized in that at least one spring element (11) is provided on the expansion element (10), which spring element, during the drilling procedure, can be received in a recess or depression (12) provided on the periphery of the expansion element (10) and, at a reversal of the direction of rotation, cooperates with at least one profiling (13) provided on at least one spreading element (7) and facing the interior of the device, in order to prevent a rotational movement the expansion element (10) and cause its displacement (14) along the longitudinal direction by the provision of a threaded connection.
10. A device according to claim 8 or 9, characterized in that at least one flushing channel (16) extending in the longitudinal direction of the device is provided within the expansion element (10).
11. A device according to any one of claims 6 to 10, characterized in that the expandable spreading elements (7, 17, 18) are arranged to be substantially uniformly distributed about the periphery of the drill rod assembly.
12. A device according to any one of claims 6 to 11, characterized in that a plurality of expandable spreading elements (17, 18) are provided about the periphery of the drill rod assembly (3) at different distances from the drill bit (2).
13. A device according to claim 12, characterized in that spreading elements (17, 18) arranged at different distances from the drill bit (2) are arranged to be relatively offset in the peripheral direction of the drill rod assembly (3).
14. A device according to claim 12 or 13, characterized in that spreading elements (17, 18) arranged at different distances from the drill bit (2) cooperate with a common expansion element (10) arranged to be displaceable along the drill rod assembly (3).
15. A device according to any one of claims 6 to 14, characterized in that the drill rod assembly (3) is divisible into subportions (3', 3"), particularly in the region of the spreading elements (17, 18), and an anchor element, in particular a screw head (21) of a cable strand anchor (22), is connectable with the drill rod assembly subportion remaining in the borehole (1) and connected with the drill bit (2).
16. A device according to any one of claims 6 to 15, characterized in that the drill rod assembly (3), in a manner known per se, is formed with a flushing channel (4) in its interior.

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