EP1400633B1 - Drill head - Google Patents

Description

The invention relates to a drill head for forming a support or solidification area in the ground with at least one drilling tool, and at least one element for introducing Bodenverfestigungssubstanz in the soil, wherein the drill head comprises a device for mixing the introduced soil hardening substance with the boring tool during the drilling process and The invention relates to a device for conveying the removed and / or dissolved soil material and the introduced soil compaction substance in the axial direction of the drill head to the mixing device, and wherein the device for conveying through at least one along a peripheral portion of the drill head extending sub-screw is arranged, which is arranged between the drilling tool and the device for mixing

Some of the soils that can be found in nature, as well as young or old soil fillings, have a condition which makes their use as a load-bearing soil either very limited or even impossible. In known soil improvement methods, first a hole, either with or without casing protection, is drilled into the soil and the resultant soil material is wholly or partially extracted from the well or changed from the former storage to either replace it with cement suspension or binder partially with cement suspension or binder to mix and then back into the well to promote. This process causes in the method in which the soil is only partially replaced (partial soil replacement), especially in cohesive soils difficulties in that lumping of the unreacted material prevents homogeneous mixing of the soil with the cement suspension and / or the binder. The method of complete soil replacement is again problematic in loose ground, since the resulting hole can collapse or break even before filling with cement suspension or binder, after which the introduction of the cement suspension or the binder in the required depth is not possible in this case.

In these two basic methods, the resulting soil conditioner substance is relatively high, while the resulting excavated material, which is partially mixed with cement suspension, set aside and must be disposed of according to the chemical composition of the binder in special waste landfills.

From the US 5 645 376 A a Bohrkopf has become known for forming a support and solidification area in the ground, are attached to the cutting and Brecharme, while the drill shank itself hollow and attached at its lower end an opening for the discharge of cement, which upon rotation of the drilling device with the broken soil is mixed. Non-rotatably connected to the drill shank shear blades are arranged in the longitudinal direction of the drill shaft between cutting blades and crushing teeth. In this way, the shear blades are decoupled from the rotary motion of the drill shaft, but are dragged during the drilling process due to the friction between them and the soil and mix it in this way with the cement. Although this mixture of soil with cement solution is made, but the blades rotate independently of the drill collar and are employed at an angle relative to the longitudinal axis. Although the cutting blades in this patent also attributed a mixing effect, in practice, this does not take place sufficiently to achieve a homogeneous mixing, which can lead to static uncertainties.

In the EP 0 436 954 A1 is described a double-tube drill head for ground mounting, which has distributed over its cylindrical body mounted rods for mixing the nozzle injected via cement suspension, which Mixing the ground material and the cement suspension, which have been broken out by way of a drill tool arranged at the end of the drill head and cut out in the form of a partial worm.

In the in the WO 94/02687 described drill head, the soil is displaced during the drilling process and filled the resulting cavity with cement suspension. Soil consolidation by mixing with soil material does not come about. The drill head has a frusto-conical shaft, along which a helical blade assembly is mounted, with which the drill head is screwed into the ground. In the upper part hydraulically pivotable arms are provided, which form by displacement a cavity in the bottom, which is filled with cement, which is introduced via nozzles in the body of the drill head.

From the GB 2 198 765 A shows a drilling tool with a longitudinal, continuous screw surface, which has interruptions. The soil stabilization mixture entering at the free end is mixed with the soil material via the screw surface, wherein the direction of rotation of the drilling tool is alternately reversed in order to obtain a thorough mixing. Rotary mixing elements without conveying effect are not provided in this drilling tool.

The object of the invention is therefore to provide a drill head of the type mentioned, which allows solidification of the soil in only one operation, the resulting excavation amount should be kept as low as possible or even avoided. Another object of the invention is to achieve the most homogeneous possible mixing of broken soil and soil compaction substance introduced in order to guarantee a desired load capacity of the solidified soil can. Another object of the invention is also to provide a drill head with which solidification can be carried out even in difficult ground conditions.

According to the invention this is achieved in that the at least one partial screw has at least one opening through which parts of the soil material without being conveyed longitudinally can slide through and a mixing action is exercised.

A rotation of the drill head thus has a longitudinal promotion and thus also necessarily an intensive mixing of the soil material with the solidification substance result. In this way, the broken up by the drilling tool soil material is mixed on the one hand in situ with the soil hardening substance, whereby the soil material does not have to be managed from the drilling hole and a collapse of the hole can not come about, on the other hand, it comes during the drilling process to a compelling movement of the soil material in the axial direction, whereby it is driven together with the soil hardening substance to the device for mixing, which is provided on the drill head. The result of this combination of longitudinal conveying and radial mixing is a homogeneously consolidated soil that ensures high compressibility. In the wellheads known from the prior art, the relatively inhomogeneous mixing in the borehole leads to vertical settlements of the solidified area, which can cause great damage to the buildings supported thereon. Load capacity and strength of the solidified area experience when erected with the drill head according to the invention a significant increase, together with the associated settlement minimization.

In order that the flow rate in the direction of the device for mixing is not too large and it does not come to a movement of the soil from the well, it can be provided that the length of the peripheral portion along which the partial screw extends, not greater than one half of the Bohrkopfumfangs is.

A further embodiment of the invention can consist in that the device for mixing the soil hardening substance with the removed soil material is formed by at least one soil mixing extension. With rotating operation of the drill head is thus for a constant mixing of Soil hardening substance and soil material taken care of.

An embodiment of the invention in which both a rotation and a simple supply of soil compaction substance is given, may consist in that the drill head has a hollow cylindrical base body whose central axis forms an axis of rotation, and the drilling tool at one end of the base body and arranged around the Rotation axis is rotatable. The supply of soil compaction substance can be done via the interior of the hollow cylindrical body. A rotary drilling operation allows a gentle soil consolidation, which is especially in the inner city area and in the vicinity of vibration sensitive structures of advantage.

Furthermore, an embodiment of the invention may consist in that the at least one bottom mixing extension is connected to the hollow cylindrical basic body and projects radially outward from the same. A rotation of the body thus automatically results in a thorough mixing of the broken up material around this.

In order to avoid an imbalance of the rotational movement, it can be provided that in each case two bottom mixing extensions project radially outwards in opposite directions at opposite circumferential points of the base body.

In this case, according to a further embodiment of the invention, the respective two bottom mixing extensions can be spaced in the longitudinal direction of the main body, whereby a mixing process promoting the division of the soil mixing processes over the main body length can be achieved.

An improved guidance of the drill head according to the invention within the borehole produced by this can be realized in the invention that the connecting lines of each two bottom mixing extensions along the base circumference by an angle, preferably offset by 90 ° to each other.

In addition to the drilling tool further Bodenbrech- and - cutting devices may be provided which allow expansion of a diameter caused by the drill core diameter to a nominal diameter. Preferably, the ground breaking and cutting devices may be formed by a plurality of peripherally distributed cutting edges.

Thus, a variant of the invention may consist in that the cutting edges are arranged on a conical end region of the base body, which adjoins the drilling tool, whereby a significant widening of the borehole is possible.

A further embodiment of the invention may consist in that the at least one partial screw at its one, the drilling tool facing end has at least two parallel arranged obliquely to the central axis of the body employed chisel elements, with the aid of the expansion of the well can be performed more quickly.

A structurally simple variant of the invention may consist in that the at least one element for introducing Bodenverfestigungssubstanz by a provided in the lateral surface of the body, variable in the opening cross-section injection nozzle for ejecting cement suspension is formed, and that the interior of the body about a high pressure pump is connected to a suspension reservoir. By using cement suspension, no additional substances such as air and / or water and / or bentonite are introduced into the soil to be improved, which helps to prevent a soil-worsening reaction. There is no contaminated by soil chemical components suspension return, which must be disposed of in hazardous waste landfills under certain circumstances.

Preferably, a plurality of injection nozzles can be provided with variable opening cross-section, which are arranged in the region of Bodenbrech- and cutting devices on the base body, so that a sufficient Amount of cement slurry for mixing with the soil material can be provided.

• Fig.1 eine schematisierte Darstellung einer Ausführungsform des erfindungsgemäßen Bohrkopfes;
• Fig.2 einen Ausschnitt aus einer Ausführungsform des erfindungsgemäßen Trägerverbaus und
• Fig.3 eine Schrägrißansicht des Bohrkopfes gemäß Fig.1.

The invention will be explained in detail with reference to the embodiments shown in the drawings. It shows

• Fig.1 a schematic representation of an embodiment of the drill head according to the invention;
• Fig.2 a section of an embodiment of the support structure according to the invention and
• Figure 3 a Schrägrißansicht the drill head according to Fig.1 ,

Fig.1 shows a drill head 10 for forming a support or solidification area in the ground, which is connected via a drill pipe connector 20 with a drill string, not shown, via which a drive torque can be transmitted. For this purpose, the drill head 10 has a hollow cylindrical base body 19, the central axis of which forms a rotation axis 11 around which it is rotatable. At the lower end of the drill head 10, a drilling tool 1 is mounted, for example, in the in Fig. 3 may be formed, wherein at the end of a shaft of this projecting cutting edges are fixed, via which the bottom can be broken in a Kernlochdurchmesser. However, the invention is not limited to a particular shape of the drilling tool, as well as mounted on the drill head 10 Bodenbrech- and cutting devices 5, 15 in one of Fig.1 and 3 deviating way can be executed.

According to Fig.1 and 3 the Bodenbrech- and cutting devices have a plurality of circumferentially distributed cutting 5, which are arranged on a cone-shaped end portion of the base body 19 which is adjacent to the drilling tool 1. These cutting edges 5 continue to widen the opening broken open by the drilling tool 1.

Via elements for introducing the soil-fixing substance 2, 3, 4, which are provided laterally on the drill head 10, the cement suspension is introduced during the drilling process in the soil material formed by the Bodenaufbrechvorgang. To carry out the method according to the invention, the drill head further comprises a device 6, 7, 8 for mixing the pressurized soil hardening substance with the soil material removed and / or dissolved by the drilling tool 1 during the drilling process. This will be the bottom in the broken soil opening in situ mixed with the cement slurry, which results in a hardening of the soil after curing of the mixture. The ground area thus solidified can perform a supporting function. All broken soil material remains in the drill hole.

According to the invention, a device for conveying the removed and / or dissolved soil material and the introduced soil compaction substance in the axial direction of the drill head to the device for mixing 6, 7, 8 is provided on the drill head 10, wherein the device for conveying in the embodiment shown by two along a peripheral portion of the main body 19 extending part screws 17 is formed, each having at its one, the drilling tool 1 near end three parallel, obliquely to the central axis of the body 19 employed chisel elements 15, which make the expansion of the drill head 10 to the nominal diameter, so that during the drilling process between the lateral surface of the hollow cylindrical base body 19 and the borehole wall, an annular space with broken soil material is formed. The number and positioning of the chisel elements 15 used is of no importance to the invention and can be varied as desired.

Preferably, the length of the peripheral portion, along which the partial screws 17 extend, not greater than half of the Bohrkopfumfanges. Since an upward movement of the broken soil material to take place, but the material should not be displaced from the well, the two sub-screws 17 are each provided with an opening 12 through which the soil material can slide. The apertures 12 may vary in size but may also be omitted.

To form support or solidification areas in the soil this is broken and then introduced into the broken soil opening soil hardening substance. According to the invention in the course of Bodenaufbrechvorganges soil material formed in the broken bottom opening with soil compaction substance in the axial direction of the bore and mixed, and allowed to cure the forming mixture. As soil hardening substance, a cement suspension is usually introduced into the broken bottom opening, any other suitable substance can also be used for it.

As elements for ejecting the cement suspension injection nozzles 2, 3, 4 are formed with a variable opening cross section in the lateral surface of the base body 19, wherein the interior of the body 19 is connected via a high-pressure pump, not shown, with a suspension reservoir. The injection nozzles 2, 3, 4 are preferably arranged in the region of the ground breaking and cutting devices 5, 15, 17 in the base body 19 and their number or their diameter is dimensioned so that a sufficient amount of cement suspension in during the drilling process for Available time is supplied to the excavated soil material.

The device for mixing the cement suspension is formed by bottom mixing extensions 6, 7, 8, which are arranged along the longitudinal axis of the base body 19 and make a rotation of the base body 19 about its longitudinal axis, a mixing of cement suspension and the broken soil material. The two sub-screws 17 exert in addition to their conveying effect on their openings 12 and a mixing action. Number and shape of the sub-worms may vary.

In each case, two of the ground mixing extensions 6, 7, 8 connected to the base body 19 project radially outwardly in opposite directions at opposite circumferential points of the base body 19, the two bottom mixing extensions 6, 7, 8 being spaced apart from one another in the longitudinal direction of the base body 19. The connecting lines of the two bottom mixing extensions 6, 7 are opposite the base circumference by an angle, preferably by 90 °, opposite the two soil mixes 8 added. The number and the longitudinal and circumferential displacement of the soil mixing processes can be adapted according to the properties of the soil material to be mixed. At the free end of the soil mixing extensions attached transverse end pieces 18 to the bottom mixing extensions 7, 8 serve the improved leadership of the drill head 10 within the bore.

The drilling head mounted on a drill string according to the invention is brought into the drill start position by means of a suitable drill. The interior of the hollow cylindrical body 19 is applied via the drill pipe, which is connected to the high-pressure pump, with the cement suspension in the composition corresponding to the respective soil either immediately before, simultaneously with or immediately after the start of drilling.

By rotating drilling down the drill head 10 according to the invention to the final depth of the soil improvement section and subsequent withdrawal is changed by the drilling tool 1 and the Bodenbrech- and -schneidvorrichtungen 5, 15 of the existing soil in its original structure or broken and by the simultaneous introduction of the cement suspension by means of the cement suspension injection nozzles 2, 3, 4 and the rotating mixing movement of the soil mixing extensions 6, 7, 8 and the conveying movement of the sub-screws 17 soil material and cement suspension continuously mixed, resulting in a new and sustainable soil structure after cement bonding. Depending on the nominal diameter of the drill head 10 and the injection nozzle 2, 3, 4, which can be varied in their opening cross-section, soil improvement sections are produced in the different diameters corresponding to the nominal diameter.

According to the method of the invention, the propulsion of the drill head must not be done by rotation. It is also the hole opening can be created by a high-pressure cement slurry jet, the same time by appropriate arrangement of the cement injection nozzles mixing the case thereby dissolved from the ground Material causes the cement suspension and thus the solidification of the substrate.

Fig.2 shows a section of a support structure for excavation protection with two embedded in the ground, adjacent beams 40, 41, which are representative of any extension of the carrier structure and which are connected to each other via a infill, which acts on the Trägerverbau, lateral ground pressure to the carrier 40, 41 forwards.

According to the invention, the supports 40, 41 are received in first, preferably columnar, bottom mounting bodies 30, 31 and the infill is formed by two second unobstructed, preferably columnar, bottom mounting bodies 35 respectively placed between the two adjacent first floor mounting bodies 30, 31 into which the beams 40, 41 are included. The number of first bottom fastening bodies 35 set between the two first floor fastening bodies 30, 31 may vary within the scope of the invention.

The cross sections of the first floor fixing bodies 30, 31 and the second floor fixing bodies 35 immediately adjacent thereto and the cross sections of adjacent second floor fixing bodies 35 are each partially overlapping, and the cross sectional centers 38 of the second floor fixing bodies 35 opposite to the connecting line 36 between the cross sectional centers of the first floor fixing bodies 30, 31 so arranged staggered that each set between the two first floor mounting body 30, 31 second floor mounting body 35 form a horizontal vault to accommodate the lateral bottom pressure can.

In the second floor fixing body 30 produced according to the invention, a steel profile 40 has been driven in the still wet state. Fine other construction variant, however, forms the inventively produced bottom fixing body 31, in the In-situ concrete piles 41 have been drilled. However, it is also possible to use another type of support for realizing the construction according to the invention.

Particularly preferably, the first and second floor fastening bodies 30, 31, 35 are each formed by a floor fastening body produced by the method according to the invention. By their intersecting and with respect to the connecting line 36 staggered arrangement, a vault is created, which resists the side-acting pressure of the soil.

In the production of the support structure according to the invention, in particular for Baugrubensicherung, supports 40, 41 are placed in the ground and it is between them formed a infill by along the course of the trainees carrier assembly, preferably columnar, mounting body 30, 31, 35 along the longitudinal abutting be set in the ground, wherein the cross sections of each adjacent attachment body are formed overlapping each other. This is preferably done by the fastening body 30, 31, 35 are placed against each other in the uncured state so that overlapping cross sections of each adjacent attachment body 30, 31, 35 form. As long as the cement suspension has not yet cured, each subsequent in the series mounting body can be formed so that it partially overlaps with the cross section of the previous mounting body in which the drill head used for it is lowered so that it in the already completed cross-section of the preceding Locking body engages. After curing, the cross sections are overlapping.

The carriers 40, 41 are spaced from each other in a predetermined pitch in the mounting body 30, 31 is introduced, wherein the pitch corresponds to a multiple of the distance between the cross-sectional centers of the fastening body 30, 31, 35, in Fig.2 the pitch is, for example, three times the center distance, and wherein those fastening body 35, between each two fastening bodies 30, 31 are placed, in which the carrier 40, 41 are introduced, are set in an arcuate course, so that they form a horizontal vault to accommodate the lateral bottom pressure can.

Claims (13)

1. A drill head for forming a support or solidification area in the soil, with at least one drilling tool (1) and at least one element (2, 3, 4) for introducing soil solidification substance into the soil, said drill head (10) having a device for mixing (6, 7, 8) the soil solidification substance introduced into the soil with the soil material eroded and/or removed by said drilling tool (1) during the drilling process, a device for transporting (17) the eroded and/or removed soil material and the soil solidification substance introduced into the soil in an axial direction of the drill head to said mixing device (6, 7, 8) being provided at said drill head (10) and said transporting device being formed by at least one partial screw (17) extending along a peripheral section of said drill head (10) and being disposed between said drilling tool (1) and said mixing device (6, 7, 8), characterised in that said at least one partial screw (17) has at least one opening (12) through which parts of the soil material may slide without being transported along the longitudinal axis and via which a mixing effect is achieved, and in that the length of said peripheral section, along which said partial screw extends, is not greater than one half of the drill head circumference.
2. The drill head according to claim 1, characterised in that the length of said peripheral section, along which said partial screw (17) extends, is not greater than one half of the drill head circumference.
3. The drill head according to claim 1 or claim 2, characterised in that said device for mixing the soil solidification substance with the eroded soil material is formed by at least one soil mixing extension (6, 7, 8).
4. The drill head according to claim 1 or claim 2, characterised in that said drill head (10) has a main body with the slape of a hollow cylinder whose central axis constitutes a rotational axis, that said drilling tool (1) is disposed at one end of said main body and can be rotated around said rotational axis, and that said at least one soil mixing extension (6, 7, 8) is connected to said hollow cylindrical main body (19) and projects radially in an outward direction.
5. The drill head according to claim 4, characterised in that two respective soil mixing extensions (6, 7, 8) project radially in an outward direction at opposite peripheral points of the body (19).
6. The drill head according to claim 5, characterised in that said two respective soil mixing extensions (6, 7, 8) are spaced apart in the longitudinal direction of the body (19).
7. The drill head according to claim 6, characterised in that the connecting lines of said respective two soil mixing extensions (6, 7, 8) are offset from each other by a certain angle, preferably an angle of 90°, along the body circumference.
8. The drill head according to any one of the preceding claims, characterized in that additionally soil breaking and soil cutting devices (5, 15) are provided.
9. The drill head according to claim 8, characterised in that said soil breaking and cutting devices are formed by several cutting edges (5) distributed around the circumference.
10. The drill head according to claim 9, characterised in that said cutting edges (5) are disposed at a conical end section of the body (19) adjacent to the drilling tool (1).
11. The drill head according to any one of the preceding claims, characterised in that said at least one partial screw (17) has, at its one end which is facing the drilling tool (1), at least two parallelly disposed chisel elements (15) adjusted in an inclined position to the central axis of the main body (19).
12. The drill head according to any one of the preceding claims, characterised in that said at least one element for introducing soil solidification substance into the soil is formed by an injection nozzle for ejecting a cement suspension (2, 3, 4) which is provided in the surface area of the main body (19) and has a modifiable opening cross-section, and that the interior space of the main body (19) is connected to a suspension reservoir via a high-pressure pump.
13. The drill head according to claim 12, characterised in that several injection nozzles (2, 3, 4) with modifiable opening cross-sections, being disposed on the main body (19) in the area of the soil breaking and cutting devices (5, 15), are provided.

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