DE2422489C2 - Earth drill and method for inserting piles or the like. - Google Patents

Description

The invention relates to an auger with a hollow shank, in the lower region of which there is a drilling helix is provided and J.er axially adjacent to the drilling helix at least one over its working diameter also carries an expandable drill bit mounted on a pin. The invention also relates to a method for setting a pile into the ground using such an auger.

There is an auger of this type known (US-PS 79 266), which four evenly around the Bohrcrachse having distributed drill bits in the form of knee core. All of these bits are in the same Axial section of the drill shank, namely underneath the Bohrwendc! and above ad; is lower ear

endc forming drill head. The drill head is used for

'Loosening of the earth to be drilled, pulling in the drill in the ground and the centering of the auger in the ground. This effect is on most likely to be expected when the drill bits are in their non-spread position, as in this case the the opposing land acting on the drill bit through the earth is the least and the axial feed per Rotation of the auger comes closest to the pitch of the helix of the drill head. With increasing Spreading of the drill bit increases the said resistance, which increases the axial advance per Rotation of the drill is smaller and smaller compared to the slope of the helix of the drill head. The drill head thereby continuously skips the spiral passages cut or pushed into the ground by him, whereby the soil is loosened, the exact guidance or centering of the drill in the soil however, it is worsened.

As far as the drill head promotes soil upwards, this gets into the area of the drill bits, which in turn cause practically no axial conveyance of the drillings, so that in the area where the loads on the auger due to the large lever arms of the drill bits, an additional one The soil is compacted, which counteracts the efficient clearing work of the drill bit then promoted more effectively upwards. This results in very high loads which, on the one hand, impair the drilling progress and, on the other hand, necessitate a relatively strong dimensioning of the drill. This known auger is therefore not suitable for drilling particularly small diameters or for particularly deep drilling. Furthermore, this known auger to no facilities for irrigation during \ 1εϊ drilling.

The invention has for its object to provide an auger of the type mentioned, which is in a wide range of different soil types

4 ', means that it has a high degree of efficiency, so that it is also under difficult conditions that arise when a hollow pile is driven into the borehole at the same time, suitable 15t.

This object is achieved in an auger of the type mentioned according to the invention in that that the drill bit is mounted above the drill helix on the shaft and both the respective drill bit as well as the lower end of the shaft have outlet openings which are connected to a supply line in the shaft and how these are designed for the passage of both flushing liquid and potting compound are. Because the drill bit is mounted on the shank above the drill helix, the drill helix lies relatively ran so that the a.n lower end of the drill

bo accruing cuttings under the action of the drill helix and additionally with the supporting effect of the Rinsing liquid emerging from the outlet openings is conveyed upwards relatively quickly and at the same time is already suspended by the rinsing liquid.

The cuttings then arrive without further compaction in the area of the drill bits in the area of action of the flushing fluid emerging from the drill bits, thereby further improving the

flowability of the drilling material as well as additional acceleration result upwards, so that the drill bit lurch through the already loosened cuttings only a very small one Experience resistance. Because the supply lines in the shaft including the outlet openings Not only designed to guide flushing liquid, but also to guide casting compound, such as mortar are, casting compound can be introduced into the deepest area of the borehole in a simple manner and thereby an intimate connection of the casting compound with the surrounding soil can be ensured. Through this isf it possible to gradually move a pile into the ground at the same time as the auger is being driven sink into the resulting borehole and after reaching the desired foundation depth, the foundation to solidify the pile by pouring the bottom of the borehole, so that a very rational work when Put forward; Piling is achieved.

There is also an auger with expandable bits known (DE-OS 16 34 488), in which the drill bit is not axially adjacent to the drill helix, but directly at sections between its ends the helix are stored. As this drill bit does not have any provision for the leakage of drilling fluid has, the passage of the drilling helix located below the drill bit acts in such a way that it does this below the drill bit compresses the drill cuttings produced during drilling towards the drill bits, thereby stressing them increases and their efficiency is deteriorated. In this respect, even the use of Swivel chisels in this auger does not solve the problem on which the invention is based cause.

Furthermore, an auger is known (US-PS 10 24 820), which is essentially by one at the bottom End of a pile to be set arranged drill head is formed. This drill head remains after Setting the pile in the borehole and thus represents a so-called lost drill head, which has only been removed once used // can ground. The frustoconical drill head has perforation openings through which is squeezed out flushing liquid as well as on its end face, but all outlet openings are approximately at the height of the drill head. Therefore, the effect of the invention cannot be achieved with this auger either be educated, which results from the fact that the subject of the invention two groups or at a distance Superposed zones of outlet openings for rinsing liquid are provided. Otherwise points the last-mentioned known auger does not have a helix.

According to another feature of the invention, which are, in particular automatically dependent on the direction of rotation, spreading and retracting drill bit with the pin on one arranged above the drill helix on the shaft Hub mounted, with the outlets of the drill bit over them and the respective pin penetrating channels connected to the supply line are. After filling in the casting compound, the drill can therefore be rotated in the opposite direction and it can be brought back the drill bit in a simple manner in their non-spread position to pull the auger out of the ground through the pile. The working diameter of the In the case of split bits, auger is expediently chosen to be somewhat larger than the outer diameter of the Pfai les.

In a further embodiment of the invention, the shaft is conical, whereby an even higher drilling performance can be achieved with reduced drilling resistance.
As shown, the invention further relates to a method for inserting a pile into the ground, in which the pile is lowered into the ground during rotation of the auger, the borehole is flushed with fluid supplied through the drill string and after reaching the

ίο Foundation depth casting compound, such as mortar, introduced as well as the drill rig is withdrawn.

In a known method of this type (US Pat. No. 10 24 820), the drill rods and the other devices are removed after the foundation depth has been reached. For this purpose, the drill rod is detached from the drill, which is lost for reuse, ie remains in the borehole. Sealing compound can only be introduced through the pile channel after the drill rod has been removed. After removing the drill string, the auger sits with its lower outlet opening on the bottom of the borehole a .. · '. That this outlet opening is sealed. Already from d ^; For this reason, no casting compound could be applied into the borehole through this outlet opening.

The other one has already been proposed (not previously published DE-PS 24 13 418), through the drill pipe of an auger after the throughput of flushing liquid also introduce a thixotropic substance into the borehole. However, such substances serve in no case as a casting compound, but are intended as a lubricating medium or corrosion protection. As Supporting medium serving substance is therefore not shed, d. H. not introduced to form a cast body, but then back out of the borehole

J5 is pushing and thus removed. The repression takes place through fresh concrete, which is intended as a casting compound and only after the drill rod has been loosened and after the removal of which is introduced from the lowered pile and thus from the borehole.

On the other hand, the invention has the task of to create a method of the type mentioned, with which it is possible in a rational manner, casting compound to bring it to the deepest point of the borehole and then to compact it immediately.

4 ") This task is mentioned in one of the procedures Kind according to the invention solved in that withdrawn and with the drill pipe of the auger at the latest during the retraction / pulling of the drill pipe over the one previously used for the flushing fluid Feeding the potting compound is fed to the borehole by the auger. This not only achieves that the earth auger remains for reuse, but with uem earth auger is still ahead its removal from the borehole has a compacting and thus solidifying effect on the potting compound exercised. Already the movement required to withdraw the auger from its lowest position inevitably leads to a mechanical compression, in particular to a pressing of the previously introduced Potting compound against the borehole wall, whereby the engagement of the potting compound in the borehole wall becomes particularly intimate. This is particularly the case if, according to a further proposal of the invention first the potting compound to the borehole

b5 is fed and then the auger is withdrawn. It is also conceivable to increase the effect mentioned by not only withdrawing the drill axially, but is also set in rotary motion.

It is particularly useful if the potting compound above a helix of the auger and in the lower region of which is fed to the borehole, so that the casting compound can be introduced very quickly and almost simultaneously over essentially the entire height of the auger.

The earth auger according to the invention and the method according to the invention are particularly suitable for Driving prefabricated concrete or sheet metal piles into a foundation intended for the construction of a building.

Further features of the invention emerge from the subclaims: a preferred embodiment of the invention is shown in the description in conjunction with the drawings and is explained in more detail below. It shows

Fi g. 1 is a view of an embodiment of the invention,

F i g. 2 shows a section along the line II-II in FIG.

3 shows the section according to FIG. 2 in another Position,

4 shows an enlarged axial section of a step e'er FIG. 1,

F i g. 5 to 7 longitudinal sections showing successive working steps of the auger.

F i g. 1 shows an auger with a shank 1, which can also be conical and has a drill bit 12. A helical drilling coil 2 is arranged on the outside of the shaft 1. A feed line 3 in The shape of a bore is provided in the shaft 1, the lower end of which has drilled outlet openings. Furthermore, in the upper area of the shaft I is a Hub 5 is provided on which drill bits 6 are pivotably arranged by means of pins 7 for free pivoting out and in. The drill bits 6 rest against stops 8 in their spread-out position.

If the hub 5 is in the direction of arrow A 5 in FIG. 2 rotated, the drill bits 6 - due to the resistive forces of the ground acting on their pointed ends 6 £ - rotated around the pins 7 in the direction of arrow A 6 until they strike the stops 8. This ends their pivoting movement and the diameter of the flight circle of the pointed ends 6E of the drill bit 6 is greatest.

On the other hand, when the hub 5 is rotated in the opposite direction to the direction of the arrow A 5, the drill bits are also pivoted about the pins 7 in the direction opposite to the direction of the arrow A 6 and then take the directions shown in FIG. 3 position shown. In this position the diameter of the flight circle of the pointed ends * t £ of the drill bit 6 is smallest. The auger also has channels 13 drilled into the pegs 7, channels 14 located in the associated drill bits 6, and outlet openings 15 in the drill bits 6.

During the drilling process, flushing liquid such as water is introduced through the supply line 3 and sprayed on the one hand through the outlet openings 4 and on the other hand through the channels 13, 14 and sprayed in the direction of the arrows A 15 from the outlet openings 15, which are thus also spray openings.

Using the earth auger described, a prefabricated, hollow cylindrical pile P driven into the earth after erecting. First, the auger is in an axial bore 16 of the pile P introduced, after which the shaft 1 in the in F i g. 4 is set in rotation while Rinsing liquid is sprayed from the outlet openings 4 will. For this purpose, the upper section of the shaft 1 hung together with the pile pan of a pile setting machine not shown in detail and rotated in this position via a drive gear 19.

As a result of the rotation of the drilling helix 2 of the shaft 1 provided on the outer circumference, the auger penetrates into the ground. while the drill bit 6 above the drill helix 2 in the in F i g. 2 spread the position shown so that the drill bit 6 during

ίο the rotation excavate the underlying soil and thereby drive the pile P arranged above it downwards in order to introduce it into the excavated borehole. At the same time, the soil is drilled open by the drill bit 12 and the drill helix 2. Included is - since the flight circle diameter D2der drill bit 6 is slightly larger than the outer diameter D 1 of the pile P is chosen - between the exposed by the drilling bit 6 borehole and the outer periphery of the pile P, a free space or gap 17 educated.

In this way, the pile P is driven into the borehole created by the drill bit 6 to a desired depth, while the friction between the pile P and the earth is caused by the drilling fluid is decreased. This is - depending on the nature of the soil - simultaneously with the rotation of the shaft 1 through the outlet openings 15 in the drill bits 6 in the direction of the arrows A 15 according to FIG. 6 sprayed to the drilling acting on the drill bit 6 resistance and also act on the pile P to reduce the frictional resistance.

When the drilling process has progressed to the predetermined stage shown in Fig. 6, if the rotation of the shaft 1 is stopped, the spraying

j5 hen flushing liquid through the outlet openings 4, 15 interrupted and then filling compound, such as mortar, into the cavity 9 of the borehole made in the ground. All kinds of suitable potting compounds can be used. For example, a re relatively poorly mixed casting compound made of sand. Cement, Mortar or the like is filled into the borehole, thereby completely embedding the pile P in the ground. Since a mixture is used with the leanly mixed potting material which is largely similar Like the earth around the pile P, this grouting material does not prevent the piles P from being pulled out of the earth if they are to be pulled after the construction has been completed. Filling potting compound into the cavity 9 is passed through the supply line 3 and the outlet openings 4, 15.

Since the inside of the cavity 9 is washed out during the drilling process by the flushing liquid emerging from the outlet openings 4, this is due to the Inside of the cavity 9 a surface of the supporting foundation 10, d. H. of the load-bearing subsurface. As a result, the gradually filled casting compound comes into direct and close contact with the supporting foundation 10, so that a soft, weak zone between the outer surface of the lump-shaped, a foundation block 11 forming Vergußtcilcs and the supporting foundation 10 is formed and one firm connection between foundation block 11 and the soil is produced.

b5 In this embodiment, the gap 17 between see the outer circumference of the pile P and the inner wall of the borehole also filled with potting compound either at the same time as the filling process

24 Il 4 »y

Potting compound into the cavity 9 through the supply line 3 in the shaft 1, or by separately pouring casting compound directly into the gap 17. This is the Post P borne even better by the earth.

When the filling of sealing compound through the inlet 'is · fuhrlcitung terminated 3, the auger is rotated in the direction of the arrow A 5 opposite direction, I't), the drill bit 6 in the in I-' i g. 3 and withdraw the position shown, after which the shaft 1 is withdrawn through the axial bore provided in the pile left in the earth to the surface of the earth, so that the arrangement according to FIG. 7 results, in which a complete foundation block 11 is made.

With the auger according to the invention ent- Γι speaking also other posts, z. B. Sheet pile wall profile, double T-beams o. The like. Be set.

For this purpose 2 sheets of drawings

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Claims (6)

Patent claims: 1. Auger with a hollow shaft in which lower area a drilling turn! is provided and the axially adjacent to Bohrwcndcl at least a drill bit mounted on a pin, which can be expanded beyond its working diameter is characterized in that the drill bit (6) above the drilling turn! (2) on Shank (1) is mounted and both the respective drill bit (6) and the lower end of the shaft (1) have outlet openings (15 or 4) which are connected to a supply line (3) in the shaft (1) and how these are designed for the passage of both flushing liquid and potting compound. 2. Earth drill according to claim 1, characterized in that that the in particular automatically expanding and retracting drill bits depending on the direction of rotation (6) with the pin (7) on a hub (5) arranged above the Bohrwendfcl (2) on the shaft (1) are stored and that the Ausiriits5iinungen (15) of the Drill bit (6) through channels (13, 14) passing through them and the respective pin (7) to the supply line (3) are connected. 3. Earth drill according to claim 1 or 2, characterized in that that the shaft (1 \ is conical. 4. Method of driving a pile into the ground using an auger according to a of claims 1 to 3, wherein the pile during rotation of the auger into the ground abese :: ki, at the same time through the borehole the drill pipe fluid supplied to the auger rinsed and, after reaching the foundation depth, casting compound, such as mortar, is introduced as well the drill pipe is withdrawn, characterized in that with the drill string length of the auger withdrawn and at the latest during the withdrawal of the drill pipe over the previously for the flushing fluid used supply supplied the potting compound through the auger to the borehole will. 5. The method according to claim 4, characterized in that that first the potting compound is fed to the borehole and then the auger is withdrawn will. 6. The method according to claim 4 or 5, characterized in that that the potting compound above a helix of the auger and in its lower Area is fed to the borehole.