DE1955623A1 - Regrooving or extension drill - Google Patents

Description

DR. KURT-RUDOLF EIKEN3ZRG PATENT ADVOCATE

• HANNOVlIl · «CHACKSTRAtai 1 · TELIFON (0511) BI 40 68 · CABLE. PATENTION HANNOVER

The Cementation Company Ltd. 200/294

Regrooving or extension drill.

The invention relates to a regrooving or reaming drill which can be used to "pre-drill" a Hole in certain areas or sections to expand a larger durometer.

In many cases it is necessary to firmly anchor a steel mast / cable or the like that is exposed to high tensile stress to the ground, for example around a retaining wall _; to secure or to fix a foundation. For this purpose, tie rods are used, which are inserted into a borehole in the subsurface and poured into it. The hole has been doing] pre-drilled in the ground beforehand to a sufficient depth. If the subsoil consists of clay or soft.; Rock, however, sometimes the tie rod cannot be anchored sufficiently in the ground and is accordingly partially pulled out of the ground again under load. ;

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In order to provide a firm tensile anchorage in clay or soft rock, it has already been proposed, at least to enlarge the borehole in a section or to provide it with a number of bead-shaped extensions. The tie rod is then inserted into this Bohruno in the shed usual way. The enlargements or bulbous Extensions can have a wide variety of shapes, but are preferably in the longitudinal direction with a diamond-shaped Cross-section executed. These extensions act in the manner of an interlocking with the subsurface, and it has it has been shown that a tension anchor produced in this way can be loaded approx. six to ten times higher than a tension anchor, which has been cast in a drill hole with a constant diameter.

Extension drills, by means of which, for example, a hole pre-drilled in a rocky subsurface can be enlarged in diameter in certain areas along its depth, are known, but these extension drills have the disadvantage that the diameter of the borehole only extends to about twice the diameter of the original borehole can be. Other enlargement drills that are used on a loamy subsoil or on a subsoil made of soft rock are also known, whereby these enlarge the borehole diameter to twice the diameter of the original hole or a little more. These drill bits have been designed to expand after insertion into the wellbore until the desired degree of magnification _f, usually this is done by means of

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mechanical-hydraulic or mechanical-pneumatic Devices that act on the drill itself and cause it to open or expand when they move located in the borehole at the desired depth. It has been found, however, that such operated devices are very prone to failure and often do not expand the drill in the desired manner to the required diameter.

According to the invention, these disadvantages are eliminated by that on the outer circumference of a rigid, rod-like core and in the core longitudinal direction at a distance from one another a number which extend in the radial direction and can be applied to the core due to elastic-flexible properties Elements are arranged, and the core at one end a device for attaching the drill to a drill shaft owns.

Such a drill according to the invention is virtually immune to failure and comes mainly in the following ways, among others for use. First, as usual, in the background one Drilled hole made with a substantially constant diameter. Then the expansion drill according to the invention attached to a drill shaft and inserted into the borehole to the desired depth by means of the drill shaft. Included are the elements extending in the radial direction due to their flexible properties on the core of the drill arranged adjacent. ' If the drill is now set in rotation, the elements attached to the core have as a result their elastic-flexible properties and as a result of the

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they acting centrifugal forces tending to move in '..-'■> radial direction from the. To spread the core of the drill and accordingly to enlarge the diameter of the drill hole at the desired location and in the desired manner

For removing the during the drilling process from the borehole walls' With broken material it is advisable that; a tube is arranged in the longitudinal direction of the core on the latter, the free end of the tube being connected to a line carrying a pressure medium and the part of the adjacent to the core ■ k pipe provided with one or more outlet openings Lst. The drilling material can thus advantageously be removed from the borehole can be rinsed out and does not need mechanical devices o.a. to be removed. In this, context is it is advantageous if the core is tubular and the * Tube is arranged in red extending into the core.

The elements arranged on the core of the drill are expediently made of rope wire, spring steel or nylon. »A decisive advantage of a drill according to the invention is that the extension of the drill hole is not limited to about twice the diameter of the original drill hole, as was previously the case; but that the elements can have a length w between four times the radius of the borehole to be expanded and a length which is slightly larger than the borehole radius "

In some cases of the borehole widening, it may be desirable that the lengthways of the core, consecutive Elements starting on opposite sides

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Ends of the core have an increasing length, wherein the maximum length is given approximately in the middle of the core. In principle, however, the elements can be found in everyone. wünsohtem pattern be arranged on the circumference of the drill core. In preferred embodiments, the elements are arranged so that they extend in the opposite direction from that Extend away core or that the elements are arranged in the form of a spiral extending along the core.

An exemplary embodiment of the invention is described in more detail below with reference to the drawings. Show it:

Pig 1 shows a cross section through an extension drill according to the invention.

2, 3 and 4 successive manufacturing steps of a borehole enlargement by means of the drill according to the invention shown in FIG.

The illustrated extension drill consists of a tubular core Ι, ζ.Β. made of steel, and has at one end 2 for attaching a drill shaft 3 an oa. 60 cm long thread · The core 1 is seen j in the longitudinal direction approximately every 2.5 cm diametrically pierced "In these borings [stanchions 5, the elements 4 are used, and by means not shown j grub screws mounted above. The elements themselves can be made of rope wire, spring steel, nylon or other suitable elastic materials.

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If one denotes the distance between the tip of the element and the circumference of the core as the length of the element ”then possess the elements starting from opposite ends of the drill core 1 have a steadily increasing length, the maximum length is reached essentially in the middle of the core 1. The maximum length of the elements 4 is preferred three to four times as large as the radius of the drill hole into which the extension drill is inserted.

A tube 6 is attached along the surface of the core by means of e.g. welding and has in the area at one end a number of openings 9.A device (not shown) is arranged at the other end of the tube 6, by means of which the pipe is connected to a line in the drill shaft 3 in which there is pressurized Gas or liquid.

The use of the enlarging drill according to the invention for enlarging or bulging a borehole is as follows. First, a borehole with a suitable diameter, "for example 15 cm, is pre-drilled in a loamy subsoil or in a subsoil made of soft rock to the depth necessary for the ground anchoring the pipe 6 to the high pressure fluid-carrying line is connected in the drill collar. the reamer is introduced into the wellbore next. Here, the elements 4 in place Längsriohtung to the core drill 1, as by means of the overall

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dashed lines 10 in Fig. 1 is indicated. If the extension drill has reached the position provided for enlarging or bulging the borehole, then it is set in rotation, with a liquid or gas being fed through the pipe 6 at the same time under pressure.

When the drill rotates, the elements 4 cut or break out of the borehole wall clay or soft rock. The detached particles are entrained by the high-pressure medium supplied through the line 6 and emerging from the openings 9 and washed out of the borehole. During the drilling process · the elements are steadily up to in

. their upright position extending in the radial direction " When using the drill shown in Fig. 1, an enlargement or bulge-shaped expansion is achieved in this way of the borehole achieved, which has a substantially diamond-shaped cross section in the longitudinal direction. Further Extensions and enlargements can then be made if the drill is in the appropriate, desired areas of the borehole is positioned. Are in the desired Way a sufficient number of expansions in the drilling hole has been created, then the drill is out of the borehole removed and the latter finally blown out to the Remove any remaining loose clay or rock particles. Then a tie rod or pull rod is pushed into the borehole and potted in its final position in the borehole.

The successive steps in manufacturing one with several enlargements or enlargements Boreholes are shown in FIGS. 2, 3 and 4.

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The individual lengths of the elements 4 shown in FIG. Extension drills are chosen so that the drill is an enlargement or bead-like extension with a diamond-shaped cross-section in the ground incorporated. The lengths of the elements can, however, also be matched to one another so that an enlargement or Extension with other longitudinal cross-sections, e.g. a rectangular one or circular cross-section.

The arrangement of the elements 4 on the circumference of the drill core 1 can still be made in any desired pattern will. Instead of the elements extending in a diametrical plane, elements can also be provided, which are arranged in a spiral shape along the core 1 «To bend the elements 4 back in the longitudinal direction of the core - to can, these are designed to be elastic, however, in a plane extending transversely to the longitudinal axis of the "core" 1 have substantially rigid properties. . / 2-

Furthermore, more than one pipe 6 carrying a pressure medium can be attached to the drill core 1. For the In the event that the core 1 is tubular, the individual tube 6 or, in the case of a plurality of tubes arranged, all of them Pipes are arranged within the core, in which case the openings provided in the pipes with associated openings communicate in the core 1.

During the drilling process, i.e. when the extension drill rotates, the individual elements are not

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It is only returned to its original position running radially to the core due to its elastic, flexible properties, but also due to the centrifugal forces acting on it as a result of the rotation.

Claims (8)

- io - claims 1. regrooving or extension drill , characterized in that on the outer circumference of a rigid, rod-like core (l) and in the longitudinal direction of the core at a distance from each other a number of radially extending, due to elastic-flexible properties on the core can be applied elements (4) are arranged, and the core at one end (2) has a device for attaching the drill to a drill shaft (3). 2. Apparatus according to claim 1, characterized in that a tube (6) is arranged to extend in the longitudinal direction of the core (l), wherein the free end of the tube is connected to a line carrying a pressure medium and the part of the tube adjacent to the core with a or several outlet openings (9) is provided. 35. Apparatus according to claim 2, characterized in that the core (i) is tubular and the tube (6) is arranged extending into the core. 4. Device according to one of claims 1 to 5, characterized in that the elements (4) consist of rope wire, spring steel or nylon. 5. Device according to one of claims 1 to 4, characterized in that the elements (k) have a length between / 4 times the radius of the bore to be expanded and a length : 0.ÜJ98- 13-55-6-23 " - li - which is slightly larger than the borehole radius «. 6. Device according to one of the preceding claims, characterized in that the elements (4) following one another in the longitudinal direction of the core (1) have an increasing length starting at opposite ends of the core, the maximum length being given approximately in the middle of the core. 7. Device according to one of the preceding claims, characterized in that the elements (4) are arranged extending in the opposite direction from the core (l). 8. Device according to one of claims 1 to 6, characterized in that the elements (4) are arranged in the form of a spiral along the core (l) extending. 0098 2 7/1 187