DK2730703T3 - Method and device for erecting a foundation element - Google Patents

Description

Method and device for producing a foundation element

The invention relates to a method for producing a foundation element in the ground according to the preamble of claim 1 and to a corresponding device according to the preamble of claim 5.

In the method, which is particularly suitable for producing a foundation element in the bed of a body of water, a pile tube is introduced into the ground, ground material is removed inside the pile tube by means of a drilling tool driven in a rotating manner and the pile tube is filled with a filling material in order to produce the foundation element.

The device comprises a drilling means with a drilling tool that can be driven in a rotating manner for removing ground material inside a pile tube, which can be introduced into the ground as part of the foundation element. In the so-called pile foundation a prefabricated steel pile is usually drilled or driven into the building ground until a ground or rock layer of sufficient bearing strength has been reached. The loads of the supporting structure, for instance a wind power plant, are transferred through the friction of the pile tube with the surrounding ground material and/or by means of the so-called end pressure of the pile tube.

It is known that the pile tube is drilled out by means of a separate drilling apparatus and filled subsequently with a hardenable mass. However, especially in the case of underwater pile foundation this method proves to be relatively laborious. WO 2010/015799 A2 describes a method for introducing a pile tube into the bed of a body of water. By means of high-pressure injection a hole is produced in the bed of the body of water, into which the pile tube is lowered. A method for introducing a tube into the bed of a body of water from a floating platform is described in US 3,672,447.

The invention is based on the o b j e c t to provide a method and a device for producing a foundation element in the ground, which permit a particularly efficient foundation element production.

According to the invention the object is achieved by a method having the features of claim 1 and a device having the features of claim 5. Preferred embodiments of the invention are stated in the dependent claims.

According to the invention the method is characterized in that during removal of the ground material a hardenable medium is passed into a lower area of the pile tube and in that in order to form the filling material the supplied, hardenable medium is mixed with the removed ground material by means of a mixing means above the drilling tool.

According to the invention the device is characterized in that above the drilling tool the drilling means has a mixing means which comprises at least one mixing blade capable of being driven in a rotating manner, with which the ground material removed by the drilling tool can be mixed inside the pile tube with a supplied, hardenable medium in order to form a filling material, whereby a foundation element comprising the pile tube and the filling material can be produced. A fundamental idea of the invention can be seen in the fact that the ground material removed inside the pile tube by a drilling means is mixed with a hardenable or settable medium, such as a suspension, in which case the mixture of ground material and hardenable medium forms the filling material of the pile tube. Thus, the production of the filling material takes place inside the pile tube and in particular above the drilling tool. In this way, a laborious conveyance of the removed ground material and a renewed filling of the pile tube with a separate filling material can be dispensed with. The drilling-out of the pile tube and the production of the filling material can take place in a single step.

The combination of a drilling tool driven in a rotating manner and a mixing means arranged directly above allows an efficient mixing of the removed ground material with the hardenable medium that is preferably supplied in the area of the drilling tool and/or the mixing means. By preference, the drilling tool is designed in such a way that removed ground material is conveyed axially upwards in the direction of the mixing means.

The mixing means can have one or several mixing blades driven in a rotating manner. By way of the actively driven mixing blades or mixing plates an especially good mixing effect is achieved.

For an improved anchoring of the pile tube in the ground it is preferred that at least a part of the filling material is passed out of the pile tube into an intermediate space between the pile tube and the surrounding ground. Basically, this can be effected in that a part of the filling material is pressed below the pile tube into the annular exterior space where it subsequently rises upwards in the intermediate space between pile tube and ground. However, it is particularly preferred that the filling material is passed via at least one lateral opening in the pile tube into the intermediate space between the pile tube and the surrounding ground. The at least one lateral opening in the pile tube is preferably located in a lower area of the pile tube approximately at the height of the drilling tool and/or the mixing means. Provision can also be made for further openings above the mixing means. By preference, a plurality of radial openings is arranged by being distributed along the circumference of the pile tube. Through the radial passing of the filling material into the annular space outside the pile tube an especially reliable anchoring of the pile tube in the ground can be attained.

Moreover, in accordance with the invention it is preferred that the introduction of the pile tube, the removal of the ground material inside the pile tube, the passing-in of the har-denable medium and the mixing of the hardenable medium with the removed ground material take place simultaneously. Hence, the drilling tool and the mixing means are operated simultaneously and in particular driven in a rotating manner. The supply of the hardenable medium takes place simultaneously with the operation of the drilling tool. In addition, along with the removal of ground material and the corresponding axial advancing of the drilling tool the pile tube is also lowered into the ground.

Thus, the method can be referred to as a single-stage method for producing a foundation element in the ground, for which reason it is particularly efficient.

In a particularly preferred embodiment of the invention provision is made in that for removal of ground material inside the pile tube a drilling means is secured on the pile tube, which has a drive means for driving the drilling tool in a rotating manner. The drilling means capable of being secured on the pile tube can have a carrying frame for ex ample which can be secured by tensioning or clamping means on the pile tube and in which a drive means or a rotary motor is accommodated for driving a drill rod. The drilling means can be secured e.g. inside the internal cross section of the pile tube so that the drilling means and the pile tube can be sunk jointly. It is also possible to provide a telescopic drill rod or to support the drill rod in an axially adjustable manner with respect to the carrying frame so that an independent axial feed motion of the drilling tool and the pile tube can take place. A simple option for the drive of the mixing blade of the mixing means can be realized in that the drilling tool and the at least one mixing blade can be driven by way of a common drill rod. For this purpose, the mixing blade is preferably fixed on an outer circumference of the drill rod above the drilling tool. By preference, several mixing blades are distributed in the circumferential direction around the drill rod.

By preference, the at least one mixing blade extends radially outwards from the central drill rod and has a foldable mixing paddle at its free end. The foldable mixing paddle is preferably supported in a pivotable manner about a horizontal axis of rotation on a basic part of the mixing blade which is fixed on the drill rod. The foldable mixing paddle renders it possible to introduce the drilling means with the mixing means axially into the pile tube past those parts with a narrowed diameter. As a result, a pile tube can be used for example that has a lower, widened area and an upper area of a smaller diameter.

Furthermore, an especially good mixing can be achieved in that the mixing means spans a larger diameter than the drilling tool. This may, for example, be advantageous if the drilling tool only works on an inner area of the pile tube and the pile tube itself has a lower cutting shoe for the removal of ground material. In such case, the wide mixing means makes it possible that a mixing effect is also provided axially above the cutting shoe of the pile tube.

In another preferred embodiment of the invention provision is made in that the drilling tool has a support ring with supporting and/or sliding elements for support on the pile tube and/or sliding along the pile tube. By preference, the support ring is an annular element that is arranged coaxially to the drill rod and has supporting or sliding elements on its outside that rest against an internal surface of the pile tube. In this way, the drilling means or the drilling tool can be centered reliably in the pile tube.

By preference, the drilling tool has a plurality of removal elements that extend in the radial direction between the outer support ring and the inner drill rod. On an underside of the drill rod a pilot bit can be arranged.

By preference, the drilling tool has at least one cutting edge which runs radially between the outer support ring and a central drill rod and has removal elements for removing ground material. In addition, ground removal elements can be arranged on an underside of the support ring. The removal elements between the support ring and the drill rod can be fixed on a guide surface, through which the ground material is passed in the direction of the mixing means. The guide means can in particular be a guide plate or a collar ring.

By preference, the device comprises a carrying structure capable of being placed onto the bed of a body of water, on which the pile tube is supported in an axially displaceable and rotatable manner. The carrying structure can be lowered for example by means of suspension ropes from a floating platform or a ship onto the bed of a body of water in order to be leveled there by means of extensible supporting feet. The carrying structure, which can also be referred to as a drilling apparatus frame, comprises, for example, a pile tube carrying frame for carrying the pile tube. For instance the carrying structure can be lowered from the floating platform together with the pile tube fixed thereon.

By preference, on the carrying structure a pile tube drive is provided for axially moving and/or for driving the pile tube in a rotating manner. By means of the drive provided on the carrying structure the pile tube can be drilled into the bed of a body of water. In particular, simultaneously to this the pile tube can be drilled out by means of the drilling means secured on the pile tube.

Furthermore, a supply means is preferably provided for supplying the hardenable medium into the pile tube. The supply means can have a supply pump and a supply line, in which case the supply line preferably ends in the area of the drilling tool and/or the mixing means. The supply line can be fixed on the pile tube or on the drilling means inside the pile tube. The supply line runs axially along a drilling axis, preferably inside the pile tube.

For facilitated introduction of the pile tube into the ground it is preferred that at its lower end the pile tube has removal elements for removing ground material. The ground re- moval elements, which are preferably arranged in an annular manner on an underside of the pile tube and which can also be referred to as cutting bodies, serve to cut the pile tube free at the borehole bottom.

As far as the device is concerned, it is furthermore preferred that the pile tube has at least one lateral or radial opening, through which the filling material can be passed into an annular space between the pile tube and the surrounding ground. The opening in the outer wall of the pile tube is preferably designed in a lower area of the pile tube. By preference, a plurality of openings is arranged by being distributed radially in the circumferential direction.

In another preferred embodiment several openings are located axially on top of each other in a lower area of the pile tube. Through the openings the ground material recently mixed with the hardenable medium reaches an area outside the pile tube where, once hardened, it securely anchors the pile tube.

According to the invention an improved mixing effect can be achieved in that in a lower area of the pile tube on its inner wall mixing elements are fixed. The mixing elements, which are in particular stationary, can be radially projecting protuberances or plates that can be arranged in a lower area of the pile tube adapted to the location of the mixing blades. By preference, the mixing elements are arranged directly above and/or below the mixing blades so that when interacting with the rotatable mixing blades a particularly efficient mixing takes place.

The invention is described further hereinafter by way of preferred embodiments illustrated in the accompanying, schematic Figures, wherein show:

Fig. 1 a perspective view of a pile tube according to the invention;

Fig. 2 a cross-sectional view of a pile tube according to the invention;

Fig. 3 a drilling means according to the invention for insertion into a pile tube; and

Fig. 4 a view from below of a pile tube according to the invention with a drilling means inserted therein.

Identical elements or those having the same effect are designated in all Figures with the same reference signs.

Fig. 1 shows a pile tube 20 according to the invention with a drilling means 40 inserted therein. The pile tube 20 comprises a tubular base body 22 and a cutting head 24 fixed thereon by means of a fixing flange. The cutting head 24 has a slightly enlarged external diameter compared to the tubular base body 22.

The lower area of the tubular base body 22 is provided with a plurality of openings 26 which are arranged in rows and distributed in the circumferential direction. The openings 26 are provided to pass a filling material from the interior of the pile tube 20 into an external, annular space between the pile tube 20 and the surrounding ground.

The entire pile tube 20 with base body 22 and cutting head 24 is intended to remain as a carrying structure in the ground. For the introduction of the pile tube 20 the cutting head 24 has at its lower end an annular cutting means or a cutting ring 27 with a plurality of removal elements 28. The cutting ring 27 or rather a lower face side of the cutting head 24 projects inwards with respect to the pipe wall lying above, hence it has a larger radial extension than the pipe wall lying above. The face side and the removal elements 28 arranged thereon extend radially inwards up to approximately the level of the inner circumference of the tubular base body 22. In other words, the space confined by the face side or the cutting ring 27 corresponds approximately to the internal cross section of the tubular base body 22.

Above the cutting means 27 the cutting head 24 comprises a mixing section 36, in which a mixing space is designed for mixing removed ground material with a supplied, hardenable medium. On a cylindrical shell surface of the mixing section 36 several radial openings 30 are designed that extend along the circumference of the cutting head 24. The openings 30 are provided to pass the filling material produced through mixing in the radial outward direction out of the pile tube 20.

The openings 30, which are in particular rectangular, are separated from each other by vertical bridges 32. Between the openings 30, by preference on an inner side of the bridges 32, stationary mixing elements 34 are fixed in each case that project inwards and can be designed as mixing plates in particular. The mixing plates each extend in a radial plane and are especially provided to interact with rotationally driven mixing blades 62 of a drilling means 40 arranged in the pile tube 20. As can be seen in Fig. 2 in particular, preferably two rows of mixing elements 34 arranged axially on top of each other can be provided for this purpose, between which the rotationally driven mixing blades 62 are able to move. The mixing blades 62 move approximately at the level of the openings 30.

The cutting head 24 constitutes a separate element in particular which can be fixed on the base body 22 in a manner such that it is exchangeable or releasable. In this way, conventional tubular base bodies of a pile tube can be retrofitted with a cutting head 24 according to the invention in order to carry out the method pursuant to the invention. To connect the cutting head 24 to the base body 22 an attachment area 38 for attachment of the base body 22 is provided at an upper end of the cutting head 24.

The drilling means 40, which is to be regarded as a separate means, comprises a carrying frame 42, which can be secured on the pile tube 20, and a drill rod 46 capable of being driven in a rotating manner, at the lower end of which a drilling tool 50 is arranged. To drive the drill rod 46 in a rotating manner a drive means 44, for example a rotary motor, is arranged in the area of the carrying frame 42.

In the illustrated embodiment the carrying frame 42 can be inserted into the pile tube 20 and clamped therein by a clamping means 48, preferably by hydraulic cylinders. Instead of such a clamping effected on the inner wall of the pile tube the carrying frame 42 can also be secured on an upper edge of the pile tube 20.

Above the drilling tool 50 a mixing means 60 is located which preferably comprises several mixing blades 62 that can be driven in a rotating manner and are fixed on the drill rod 46. The drill rod 46 can be of telescopic design, allowing the drilling tool 50 and the mixing blades 62 to move axially inside the pile tube 20. Thus, the loosened ground can be mixed effectively with hardenable suspension.

The mixing blades 62 each have a basic element 64 attached to the drill rod 46 and a mixing paddle 66 supported in a pivotable manner on the basic element 64. The openings 30 of the mixing section 36 are located approximately at the level of the mixing blades 62.

As can be taken from Fig. 2 in particular, the basic elements 64 are designed in such a way that the drilling means 40 can be inserted axially through the base body 22 of the pile tube 20 and past the stationary mixing elements 34 of the cutting head 24. In doing so, the outer mixing paddles 66 are folded in. In a folded out operating position illustrated in Fig. 2 the mixing paddles 66 extend radially outwards from the basic elements 64 into a radial outer area of the cutting head 24, in particular between the rows of the mixing elements 34. A device 10 according to the invention for producing a foundation element in the ground can furthermore have a carrying structure, not shown in the Figures, that is capable of being placed onto the bed of a body of water. In particular, the carrying structure can have extensible supporting feet for leveling the carrying structure on the bed of a body of water. By preference, on the carrying structure in a lower and in an upper area a clamping and rotation means is located in each case, with which the pile tube 20 can be rotated and/or pivoted. Moreover, in a lower area of the carrying structure, which can also be referred to as a drilling apparatus frame, an axial displacement means can be provided, through which the pile tube 20 can be introduced into the ground.

For the supply of a hardenable medium a supply means is provided which can have a duct in a hollow stem of the drilling means or a supply line on the pile tube 20. The hardenable medium, which can in particular be a hardenable liquid or suspension, can also be injected under high pressure.

Fig. 3 shows a drilling means 40 according to the invention without pile tube 20. At an upper end of the drilling means or drilling equipment a mounting suspension 43 is located, with which the drilling means 40 can be lowered into the pile tube 20 or withdrawn therefrom for instance by way of a suspension rope.

In Fig. 4 the annular cutting means 27 of the pile tube 20 with the removal elements 28 can be seen. Inside the cutting ring 27 a circular opening is formed, the diameter of which approximately corresponds to the internal diameter of the tubular base body 22. The drilling tool 50 of the drilling means 40 comprises a support ring 56, on the outside of which supporting elements 58 are provided for support on the cutting head 24. In this way, the drilling tool 50 can be centered securely inside the cutting head 24. Between the support ring 56 and the drilling axis or the drill rod 46 a plurality of guide plates 54 extends, on which several removal elements 52 are arranged in each case for the removal of ground.

For the production of a foundation element in the ground, more particularly underwater, the carrying structure, not shown in the Figures, is initially lowered onto the bed of a body of water and leveled by means of extensible supporting feet. By means of a clamping and rotation means the pile tube 20 is drilled into the ground. While the pile tube is being drilled and/or pressed into the bed of a body of water, the drilling means 40 on the inside loosens the ground and mixes it with the hardenable medium supplied via a supply line. When the desired final depth of the pile tube 20 has been reached and the interior space of the pile tube 20 and, where applicable, the intermediate space between pile tube 20 and borehole wall in the bed of the body of water is filled with hardenable suspension, the drilling means 40 is, upon rotation of the mixing blades 62, withdrawn and removed from the pile tube 20. The pile tube 20 with the tubular, open base body 22 and the lower cutting head 24 with removal elements 28 or cutting means 27 remains in the bed of the body of water.

Claims (16)

A method of setting up a foundation element in the ground, especially in a seabed, in which a pile pipe (20) is placed in the ground, which serves ground material within the pile pipe (20) by means of a rotary driven drilling tool (50) and the pile pipe ( 20) is filled with a filling material in order to produce the foundation element, characterized in that - during the removal of the soil material, a medium which can be cured is fed into a lower region of the pile pipe (20) and - that the medium which can be introduced cured, in order to form the filler, mix with the ground material above the drilling tool (50) by means of a mixing device (60). Method according to claim 1, characterized in that the filler material is led into a space between the pile pipe (20) and the surrounding soil via at least one opening in the side (26, 30) of the pile pipe (20). Method according to claim 1 or 2, characterized in that the insertion of the pile tube (20), the removal of the soil material within the pile tube (20), the insertion of the hardenable medium and the mixture of the hardenable medium with the removed soil material takes place simultaneously. Method according to one of Claims 1 to 3, characterized in that for drilling soil material within the pile pipe (20), a drilling device (40) is attached to the pile pipe (20) which has a driving device (44) for rotary operation of the drilling tool. (50). Apparatus for setting up a foundation element in the ground, especially in a seabed, comprising a drill device (40) with a rotatable drill bit (50) for removing soil material within a pile pipe (20), which can be placed in the ground as part of the founding element, characterized in that the drilling device (40) above the drilling tool (50) has a mixing device (60) which comprises at least one rotatable drive mixer (62) and with which the soil material removed from the drilling tool (50), can be mixed within the pile tube (20) with a hardenable feed medium to form a filler material, whereby a foundation element comprising the pile tube (20) and the filler material can be produced. Device according to claim 5, characterized in that the drilling tool (50) and the at least one mixing vane (62) can be operated via a common drill rod (46). Device according to claim 5 or 6, characterized in that the at least one mixing wing (62) extends from a central drill rod (46) and at its free end has a collapsible mixing blade (66). Device according to one of claims 5 to 7, characterized in that the mixing device (60) spans a larger diameter than the drilling tool (50). Device according to one of claims 5 to 8, characterized in that the drilling tool (50) has a support ring (56) with supporting elements (58) for support on the pile pipe (20). Device according to one of claims 5 to 9, characterized in that the drilling tool (50) has at least one cutting edge extending radially between an outer support ring (56) and a central drill rod (46) with removal elements (52) for removing soil material. Device according to one of claims 5 to 10, characterized in that a supporting structure is provided which can be set down on the seabed, on which the pile pipe (20) is mounted axially displaceable and rotatable. Device according to claim 11, characterized in that a pile tube drive for axial movement and / or for rotary operation of the pile tube (20) is provided on the support structure. Device according to one of claims 5 to 12, characterized in that an insertion device is provided for introducing the curable medium into the pile tube (20). Device according to one of claims 5 to 13, characterized in that the pile tube (20) has at its lower end removal elements (28) for removal of soil material. Device according to one of claims 5 to 14, characterized in that the pile pipe (20) has at least one opening (26, 30) in the side through which the filler material can be led into an annular space between the pile pipe (20) and the surrounding soil. Device according to one of claims 5 to 15, characterized in that mixing elements (34) are fixed in a lower region of the pile pipe (20) at its inner wall.