EP1888878B1 - Method and device for drilling, particularly percussion drilling 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 drilling or rotary percussion drilling a hole in soil or rock material and fixing an anchoring in the hole. To this end, a drilled hole is made by a drill bit (3) mounted on a drill rod (2). According to the invention, the drill rod (2), on the rear side facing away from the drilling surface (5) of the drill bit (3), is surrounded at a distance from the drill bit (3) by an anchoring element (4) whose outside dimension exceeds, at least in part, the circumference of the drilled hole made by the drill bit (3) whereby enabling a constructively easier and more reliable securing of the anchoring inside the drilled hole.

Description

The present invention relates to a method for percussion or rotary impact drilling a hole in soil or rock material and defining an anchor in the hole, wherein a borehole is formed by a drill bit mounted on a drill bit, as well as a device for impact or Rotary drilling a hole in soil or rock material and defining an anchorage in the hole, wherein a drill hole is formed by a drill bit supported on a drill string.

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 string remains in the borehole and a subsequent backfilling a correspondingly good anchor effect can be achieved.

A modified embodiment of a method and an apparatus for drilling a hole and forming an anchor is the WO 02/088523 A1 it can be seen in which the drill pipe is removed from the well to form the anchorage after completion of the drilling operation, followed by a separate expansion element is taken from outside the borehole in the interior of the anchoring element for the formation of the anchorage and the expansion of the anchoring element.

Alternatively, it is after making a well known to remove the drill with the drill pipe from the well, then an anchor or an anchor device is introduced into the well, for example, from the 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 , of the EP-A 0 875 663 and further references embodiments are known in which the subsequently introduced, for example, tubular anchoring is held by appropriate holding elements on a reduced compared to the final diameter, after which it comes after complete insertion into the borehole in contact with the borehole wall to achieve a desired anchoring effect is pressed. A disadvantage of this known prior art, on the one hand, the fact that the borehole must be prepared in a first process step, after which the drilling tool including the drill string in a further process step, the anchor device is introduced into the possibly a large length having borehole, then subsequently An investment in the borehole wall succeeds. It is immediately apparent that not only for the two separate steps a correspondingly increased time required is, 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 provide a method and a device of the type mentioned, with a structurally simple means a provisional backup already during the drilling process and a reliable anchoring immediately after completion of the drilling process can be achieved.

To solve these problems, a method of the type mentioned is essentially characterized in that an anchoring element surrounding the drill string is frictionally introduced into the well, in particular at a distance from the drill bit and that after completion of the well, the anchoring element is widened that the drill string after completion the borehole is retracted in the direction of the anchoring element and the anchoring element is widened by an expansion element mounted on the drill string on the side of the drill bit facing away from the excavation surface. Characterized in that according to the invention a surrounding the drill string anchoring element frictionally is introduced into the well, it is ensured that a provisional anchoring effect is achieved by the frictional action between the outer periphery of the anchoring element and the inner circumference of the borehole, so that at any time a provisional securing of the anchor formed by the anchoring element and the drill bit arranged thereon achievable is. The fact that according to the invention after completion of the well, the anchoring element is additionally expanded in abutment against the borehole wall, a correspondingly secure and reliable anchoring effect immediately after completion of the well and in particular without additional steps in contrast to the prior art achieved where after completion of the well Removal of the drill pipe and the drill bit and a subsequent introduction of an anchor element with provided on the circumference anchoring element was carried out.

For a particularly simple and reliable anchoring of the anchoring element after completion of the borehole is proposed that the drill pipe is bent back after completion of the borehole in the direction of the anchoring element and the anchoring element is expanded by a drill string on the side facing away from the excavation surface side of the drill bit expander. The fact that the anchoring element according to the invention frictionally engaged and thus secured in position is introduced into the interior of the borehole, the drill string together with the drill bit can retract over a the section between the drill bit and the anchoring element corresponding length from the borehole, whereupon the anchoring element by a mounted on the drill string expansion element in Plant is widened to the well and additionally pressed.

To determine the anchoring effect or securing effect, which can be achieved by anchoring the anchor produced by the drill string, is proposed according to a further preferred embodiment that the strength or resistance of the anchorage after expansion of the anchoring element, in particular by setting a tester on the drill string on the from the well protruding end is checked. Such a review is possible in different ways and allows conclusions about the anchoring performance achieved and / or the timing or maintenance of the anchoring effect.

In the event that, for example, displacements of soil or rock layers, in particular during the continued activities in a vicinity of the borehole produced displacements in the region of the anchor and thus possibly a reduction of the anchoring effect are found, it is proposed according to a further preferred embodiment that upon or after detection of a reduced anchorage resistance, the drill pipe is again subjected to impact or rotary impact drilling to increase the length of the borehole. It is thus possible with the method according to the invention, after providing an optionally only temporary anchoring by widening of the anchoring element on finding an insufficient or possibly decreasing anchoring effect using the drill pipe located in the wellbore and the drill bit mounted thereon to continue the drilling process and to increase the length of the borehole, in particular after extension with a corresponding additional drill string element, to drive the borehole deeper into the soil or rock material and, if appropriate, to arrive in layers with better anchoring action. Characterized in that the anchoring element is taken directly at a distance from the drill bit in continuation of the drilling process, it allows for a such increase in the length of the borehole through the anchoring element, which in turn is frictionally engaged or placed in contact with the borehole inner wall, a provisional backup and subsequently achieve a simple determination of the anchoring element by widening.

In order to achieve an optionally greater anchoring effect or performance after completion of the continued drilling activity, it is proposed according to a further preferred embodiment that, after increasing the length of the borehole, the anchoring element is widened to an outer circumference which is larger than the first expansion process.

To solve the above-mentioned objects, a device of the type mentioned above is substantially characterized in that the drill string is surrounded at the remote from the excavation surface of the drill bit back at a distance from the drill bit of an anchoring element whose outer dimension at least partially the circumference of borehole produced by the drill bit exceeds that on the side facing away from the excavation surface of the drill bit an expanding element tapering from the drill bit in the direction of the anchoring element is provided, which after completion of the bore by retraction of the drill pipe from the wellbore in the expandable anchoring element can be introduced. As noted above, due to the fact that the anchoring element, the outer dimension of which at least partially exceeds the circumference of the wellbore produced by the drill bit, is substantially frictionally engaged in the interior of the wellbore during the drilling operation, a simple temporary downhole safeguard is available to deliver. Furthermore, such an expanding element, which tapers in the direction of the anchoring element, permits a simple and reliable entry of the expansion element into the end region of the anchoring element facing the drill bit, whereby a corresponding increasing widening of the anchoring element as a result of the conical taper or expansion as it enters the interior of the anchoring element is achieved by pressing against the borehole inner wall.

In order to enable a reliable introduction of at least partially a larger outer dimension relative to the outer periphery of the drill bit having anchoring element into the interior of the borehole, without causing excessive forces, is proposed according to a preferred embodiment that the anchoring element of a slotted in particular in the longitudinal direction of the tube and / or is formed by a tube having portions of reduced outer circumference. Such a slotted tube or pipe, which has portions of a reduced outer circumference or reduced external dimensions, can be partially vary slightly in size to adapt to different geological conditions, always ensuring that a frictional engagement is present at least in some areas and thus a provisional securing of the anchoring element during the production of the borehole can be achieved.

In order to enable a simple and reliable introduction of the anchoring element, which at least partially outside the outer circumference of the drill bit exceeds the outer dimensions, provided according to a further preferred embodiment, that the anchoring element is formed at its end facing the drill bit with a chamfer. Such a taper or taper on the end facing the drill bit end of the anchoring element in particular prevents seizure or wedging on the inner wall of the borehole during insertion of the anchoring element during the drilling process.

As already indicated above, in the event that a reduction of the anchoring effect should be detectable, for example, over time, in particular when carrying out further work in an immediate vicinity of the borehole, a simple enlargement of the length of the borehole by a renewed recording of the drilling operation be made. In this context, in particular, the expander element, which conically tapers in the direction of the anchoring element, can be correspondingly easily deployed from the anchoring element when the drill string is acted on and, as a consequence, the drilling process can be carried out or continued via the upstream drill bit.

For a proper and reliable positioning of the anchoring element both during the drilling process and during the expansion process to achieve the desired Anchoring effect is proposed according to a further preferred embodiment, that at the end facing away from the drill bit end of the anchoring element, a stopper which can be fixed to the drill pipe is provided. Such a stop, which can be fixed to the drill pipe, may be formed, for example, in the manner of a nut or a threaded annular element which can be fixed in a threaded drill pipe in adaptation to the intended positioning of the anchoring element on the drill pipe.

In order to further increase the length of the well, if necessary, to achieve a simple reduction in the outer dimensions of the expanded anchoring element so as not to introduce excessive frictional forces from the anchoring element into the well wall during continuation of the drilling operation, it is proposed according to a further preferred embodiment, in that the anchoring element is formed, at least in its end region facing the drill bit, from a material with a memory effect biased in the direction of a reduction of the outside dimension. After removal of the expansion element from the anchoring element, the anchoring element returns at least partially or in the drill bit facing portion substantially back to its original outer dimensions, so that a reliable insertion of the anchoring element is also possible during the continued drilling operation.

In order to avoid the introduction of excessive frictional forces, which counteract the drilling process, during the drilling operation by the at least partially a larger outer circumference or larger outer dimensions relative to the drill bit having anchoring element is proposed according to a further preferred embodiment, that the outer dimension of the anchoring element during the drilling process exceeds the outer circumference of the drill bit by a maximum of 10 percent, preferably about 3 to 5 percent.

• Fig. 1 einen schematischen Teilschnitt durch eine erste Ausführungsform einer erfindungsgemäßen Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens während des Bohrvorgangs;
• Fig. 2 eine Seitenansicht auf die Ausführungsform gemäß Fig. 2;
• Fig. 3 eine Vorderansicht auf die Bohrkrone entsprechend dem Pfeil III in Fig. 1;
• Fig. 4 einen Schnitt entlang der Linie IV-IV der Fig. 2;
• Fig. 5 eine Seitenansicht auf die Ausführungsform gemäß Fig. 1 und 2, wobei das Bohrgestänge zum wenigstens teilweisen Aufweiten des Verankerungselements zurückgezogen ist;
• Fig. 6 eine Schnittansicht durch die Ausführungsform gemäß Fig. 5; und
• Fig. 7 eine Seitenansicht entsprechend Fig. 2 auf eine abgewandelte Ausführung zu einer erfindungsgemäßen Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens; und
• Fig. 8 einen Schnitt entlang der Linie VIII-VIII der Fig. 7.

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

• Fig. 1 a schematic partial section through a first embodiment of a device according to the invention for carrying out the method according to the invention during the drilling process;
• Fig. 2 a side view of the embodiment according to Fig. 2 ;
• Fig. 3 a front view of the drill bit according to the arrow III in Fig. 1 ;
• Fig. 4 a section along the line IV-IV of Fig. 2 ;
• Fig. 5 a side view of the embodiment according to Fig. 1 and 2 wherein the drill pipe is retracted to at least partially expand the anchoring element;
• Fig. 6 a sectional view through the embodiment according to Fig. 5 ; and
• Fig. 7 a side view accordingly Fig. 2 to a modified embodiment of a device according to the invention for carrying out the method according to the invention; and
• Fig. 8 a section along the line VIII-VIII of Fig. 7 ,

In Fig. 1 and 2 is generally denoted by 1 a device for producing a borehole, not shown, wherein a drill bit 3 is mounted on a particular hollow drill string 2, which by a drive device not shown in detail, which acts on the protruding from the borehole end of the drill string 2, is driven to a rotating and / or beating movement for producing the borehole not shown in detail.

At a distance from the drill bit 3, an anchoring element 4 is provided, the outer circumference and outer diameter of those the drill bit 3 slightly exceeds, as can be seen from 3 and 4 is apparent, wherein it is shown that the diameter D (1) of the drill bit 3 is smaller than the diameter D (2) of the anchoring element 4.

At the end facing away from the excavation surface 5 of the drill bit 3 end, a widening element 6 is mounted on the drill pipe 2 between the drill bit 3 and the anchoring element 4, which has a tapered in the direction of the anchoring element 4 or reduced cross-section.

In addition, it can be seen that at the end facing away from the drill bit end of the anchoring element 4 on the drill pipe 2 a stop, for example in the form of a ring 7 is provided, on which the anchoring element 4 comes into abutment.

For a reliable introduction of the anchoring element 4 during the drilling operation, the anchoring element 4 at its end facing the drill bit 3 a chamfer or taper 8, which allows easy insertion during the frictional engagement on the inner wall of the well.

Out Fig. 4 Furthermore, it can be seen that the cylindrical or tubular anchoring element 4 has a longitudinally extending slot 9, which according to the dimensions of the borehole inner wall prevents introduction of an excessive frictional force.

In order not to have to overcome excessive frictional forces during insertion of the anchoring element 4 is about In addition, it can be seen that the outer dimension of the anchoring element 4 during the drilling process, the outer circumference of the drill bit 3, as shown in FIG 3 and 4 is shown to exceed a maximum of 10 percent, for example, about 5 percent.

In FIGS. 5 and 6 It is shown how after completion of a drilling operation, the drill pipe 2 and the drill bit 3 are withdrawn together with the expander 6 according to the arrow 10 against the drilling direction toward the anchoring element 4, wherein by entering the expanding toward the drill bit 3 expander 6th the anchoring element 4 is correspondingly widened at the end facing the drill bit 3 and placed in an additionally secured position on the borehole wall.

Should be on a not-known and known per se device, which is set at the protruding from the borehole end of the drill string 2 in the manner of a chip nut, it can be seen that the anchoring performance or effect of at least partially expanded anchoring element 4, for example due to Rock displacements or the like. Decreases, it can be in a simple manner by a renewed action on the projecting out of the borehole end of the drill string 2, the expansion element simply from the anchoring element 4 against the arrow 10 in Fig. 5 deploy and continue the drilling process on the drill bit 3 accordingly.

After achieving a greater length of the borehole again the expansion element 6 is withdrawn with the drill bit 3 in the anchoring element 4, wherein, for example, the Increase the securing or anchoring effect the expansion element 6 on the in FIGS. 5 and 6 shown state deeper into the anchoring element 4 can be introduced or withdrawn, so that a correspondingly larger expansion of the outer periphery of the anchoring element 4 to achieve an increased anchoring effect is possible.

At the in FIGS. 7 and 8 illustrated device 1, an anchoring element denoted by 11 is used, which in contrast to the embodiment according to the Fig. 1 to 6 is not provided with a longitudinal slot, but at its outer periphery portions of reduced diameter or reduced dimensions 12, which in turn prevent excessive frictional force during the drilling process. In this embodiment as well, the partial regions of the anchoring element 11 which are different from the partial regions 12 are formed with an enlarged diameter or enlarged external dimensions relative to the drill bit 3.

As in the previous embodiment, after completion of the wellbore, retraction of the drill bit 3 and the expansion member, again indicated 6, follows into the end of the anchoring element 11 facing the drill bit 3 and again chamfered 8 to expand the anchoring element 11 and provide a correspondingly improved one anchoring effect. Also in the embodiment according to Fig. 7 For the positioning of the anchoring element 11, an annular stop 7 is provided.

To further support the reduction of the outer diameter or the outer dimensions of the anchoring element 4 or 11, in particular on continuation of the bore to achieve a greater length of the borehole, beyond a material with a memory effect, at least in the drill bit 3 facing portion be used to achieve a corresponding reduction in the outer dimensions after deployment of the expansion element 6, so that excessive frictional forces do not occur during the continued drilling process.

The length of the anchoring elements 4 and 11 and their distance from the drill bit 3 and the expansion element 6 can be selected by the stop 7 according to the circumstances. Furthermore, it can be seen from the above representations that degraded material can be discharged through the formed between the anchoring element 4 and 11 and the outer periphery of the drill pipe 2 cavity or annulus 13 readily in a region behind the anchoring element 4 and 11, for which corresponding Passage opening are also provided in the region of the stopper 7.

Furthermore, when using a hollow drill pipe 2 in a manner known per se, a cooling or rinsing fluid can be discharged into the area of the drill bit 3. About such a central channel 14 of the drill string 2 can also, in particular after a final completion of the well also a curable composition, if necessary, in particular in the area of the drill bit 3 and the anchoring element 4 and 11 are applied to further increase the anchoring effect.

Claims (10)

1. A method for drilling, particularly percussion or rotary percussion drilling, a hole in soil or rock material and fixing an anchorage in said hole, wherein a borehole is formed by a drill bit (3) mounted on a drill rod assembly (2), characterized in that an anchoring element (4, 11) surrounding the drill rod assembly (2) is introduced into the borehole in a frictionally engaged manner at a distance from the drill bit (3), and the drill rod assembly (2) is retracted in the direction to the anchoring element (4, 11) after the completion of the borehole, and the anchoring element (4, 11) is expanded by an expansion element (6) mounted on the drill rod assembly (2) on the side of the drill bit facing away from the working surface.
2. A method according to claim 1 or 2, characterized in that the strength or resistance of the anchorage is checked after the expansion of the anchoring element (4, 11), in particular, by fixing a checking device to the drill rod assembly (2) on the end projecting out of the borehole.
3. A method according to claim 2, characterized in that during or after the detection of a reduced resistance of the anchorage, the drill rod assembly (2) is again powered up for drilling, particularly percussion or rotary percussion drilling, to enlarge the length of the borehole.
4. A method according to claim 3, characterized in that the anchoring element (4, 11), after an enlargement of the length of the borehole, is expanded to an outer periphery increased relative to that resulting from the first expansion procedure.
5. A device for drilling, particularly percussion or rotary percussion drilling, a hole in soil or rock material and fixing an anchorage in said hole, wherein a borehole is formed by a drill bit (3) mounted on a drill rod assembly (2), characterized in that the drill rod assembly (2), on its rear side facing away from the working surface (5) of the drill bit (3) at a distance from the drill bit, is surrounded by an anchoring element (4, 11) whose external dimension at least partially exceeds the periphery of the borehole produced by the drill bit, on the side facing away from the working surface (5) of the drill bit (3), an expansion element (6) tapering from the drill bit (3) towards the anchoring element (4, 11) is provided, which is capable of being introduced into the expandable anchoring element (4, 11) after the completion of the bore, by a retraction of the drill rod assembly (2) from the borehole.
6. A device according to claim 5, characterized in that the anchoring element is formed by a pipe (4) which is slotted in the longitudinal direction and/or by a pipe (11) having portions (12) of reduced outer periphery.
7. A device according to claim 5 or 6, characterized in that the anchoring element (4, 11) is formed with a bevel (8) on its end facing the drill bit.
8. A device according to any one of claims 5 to 7, characterized in that a stop (7) capable of being fixed to the drill rod assembly (2) is provided on the end of the anchoring element (4, 11) facing away from the drill bit (3).
9. A device according to any one of claims 5 to 8, characterized in that the anchoring element (4, 11), at least in its end region facing the drill bit, is formed by a material with memory effect, which is biased towards a reduction of the external dimension.
10. A device according to claim 6, characterized in that the external dimension of the anchoring element (4, 11), during the drilling operation, exceeds the outer periphery of the drill bit (3) by a maximum of 10 percent, preferably about 3 to 5 percent.

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