METHOD FOR FORMING A FOUNDATION PILE IN THE GROUND

Description

The invention relates to a method for forming a foundation pile in the ground, in particular in a bottom of a body of water, in which a drilled hole is created in the ground, a pile tube is gripped by means of a handling device and is inserted into the drilled hole, and a curable medium is introduced into an annular space between a wall of the drilled hole and an outer circumference of the pile tube, which medium cures to form the foundation pile, according to the preamble of claim 1.

A method and an assembly for producing a foundation pile for a structure in the water is known from EP 2 930 275 A1. In this method, firstly a bore comprising a support tube is created in the ground. The drilled hole resulting in the process is filled with a liquid, in particular water. A pile tube is inserted into the tubed drilled hole being such formed, for which pile tube a simple steel tube having a tubular main body is used. Subsequently, the exterior support tube is pulled and the annular space between the inserted pile tube standing on the bottom of the drilled hole, and the surrounding drilled hole wall, is filled with a curable medium. The surrounding water can remain inside the pile tube. The loading capacity of the foundation pile created in this way is determined by the outer lateral surface of the inserted pile tube relative to the surrounding ground, with the cured medium in the surrounding annular space. The interior filled only with water can, if required, be used for introducing for example measuring or testing devices.

A device for handling and inserting a pile tube into a drilled hole is known from WO 2021/180515 A1. In this case, the device is configured for attachment to a support cable of a crane. An annular edge of the pile tube can be grasped in a force-fitting manner by means of gripping elements. Overall, the device is configured such that the pile tube can be pivoted out of a horizontal storage position into a vertical installation position.

An assembly and a method for producing an underwater foundation using an underwater drilling rig is disclosed by US 2010/0296875 A1. The underwater drilling rig can be placed on a bottom of a body of water. A foundation drilled hole is created by means of tubular elements. The tubular elements can at the same time also serve for anchoring the drilling device under the water.

In the known methods, after insertion of the pile tube into a created drilled hole, the outer annular space between the lateral surface of the pile tube and the surrounding drilled hole wall is filled. For this purpose, it is known to insert one or more feed hoses into the annular space, via which hoses a curable medium, such as mortar or a cement suspension, is introduced into the annular space. In this case, the introduction of the curable medium should as far as possible take place such that the annular space is filled from the bottom, such that liquid located in the annular space, in particular water, is displaced by the curable medium from the bottom to the top.

The insertion of the hose into the annular space generally takes place manually from outside the drilled hole. In the case of drilled hole depths of 10 metres and more, the problem resides that a feed hose can get caught in a central region of the drilled hole, and thus does not reach as far as the bottom of the drilled hole. This generally cannot be identified from outside of the drilled hole. If, in the case of an incorrectly inserted feed hose of this kind, the curable suspension is supplied, liquid may remain in the annular space below the feed hose and become enclosed by curable suspension located thereabove. In such a case, a pile tube would not be connected with the surrounding ground over the entire length, following curing of the suspension. As a result, the loading capacity of a correspondingly formed foundation element is reduced, such that a reliable foundation is no longer ensured.

Reworking of the foundation element may be required, which can be very time-consuming and costly in terms of costs. Possibly is also that rebuilding of the foundation element may be required.

It is further known to provide a feed line for a curable suspension also inside the pile tube. Curable medium can then be conducted inside the pile tube via the at least one feed line, as far as the lower region of the pile tube, and can be introduced into the annular space outside the pile tube via corresponding passages. In the case of this method, a corresponding feed for the curable suspension must be arranged, after introduction of the pile tube, either as far as the passage into the pile tube in the pile tube or to an upper connection on the pile tube. The production of a corresponding connection is time-consuming and labour-intensive, and is also associated with the risk of errors.

The underlying object of the invention is to specify a method by means of which it is possible to produce a foundation pile in the ground in an efficient and reliable manner.

The object is achieved by a method having the features of claim 1. Preferred embodiments of the invention are specified in the dependent claims.

The method according to the invention is characterised in that the curable medium is introduced into the drilled hole via the handling device.

A basic concept of the invention resides in that of using the handling device not only for gripping and inserting the pile tube into the drilled hole, but also for introducing the curable medium into the drilled hole. The handling device is in particular not released from the pile tube after the pile tube has been inserted into the drilled hole, but can remain at a defined initial position on the pile tube, which was taken outside the drilled hole when the pile tube was gripped by the handling device. The relative position, thus specified, between the pile tube and handling device makes it possible for a reliable feed of the curable medium to take place via the handling device.

A preferred embodiment of the invention consists in that the curable medium is introduced into the drilled hole, while the pile tube is held by the handling device. In this case, the handling device can grip the pile tube in a storage position, in particular in a horizontal position, and thus preferably be connected thereto in a force-fitting manner. A fixed relative position between the handling device and the gripped pile tube exist thus from the beginning. In this case, a defined relative position between the pile tube and the handling device can be specified. In this initial position, the feed of the curable medium to the pile tube can then take place after insertion of the pile tube into the drilled hole.

According to a further development of the method according to the invention, it is preferred for the curable medium to be conducted by means of at least one conveying line, through the handling device, up to at least one feed opening on the pile tube, wherein the curable medium is conducted through the tube wall of the pile tube via at least one line, and exits into the annular space via at least one outlet opening on the outer circumference of the pile tube. One or more conveying lines for feeding the curable medium, in particular a mortar or a cement suspension, from a depot, preferably with a pumping device, to the pile tube, are arranged on the handling device. The at least one conveying line can be rigidly attached to the handling device, or can be attachable only retrospectively after the pile tube has been gripped. The curable medium is transferred, via at least one feed opening, to the pile tube, from the conveying line of the handling device, wherein said medium is conducted from the feed opening, via one or more lines, which can also be referred to as pile lines, to the outer circumference of the pile tube, in a lower region. This ensures a reliable feed of the curable medium into the lower region of the annular space.

In principle it is sufficient for a single conveying line to be provided on the handling device and for likewise just one single line for feeding the curable medium to be provided on the pile tube. In order to maintain the functionality in the long term, it is preferred, according to a further development of the invention, for at least two conveying lines and/or lines to be provided, which can be switched by at least one valve means in such a way that they are connected in parallel for forming a dual feed, or are connected in series for rinsing operation. When at least two lines are provided, a rapid feed of the curable medium can take place. Furthermore, when two lines are arranged a valve means can be provided such that said valve means can interconnect the two conveying lines on the handling device and/or the two lines on the pile tube, such that these are connected in series. Thus, a feed can take place via a first conveying line or line, and a discharge of a rinsing liquid can take place via the second conveying line or line. As a result, the conveying lines or lines can be rinsed and thus protected against blockage by cured medium. This makes it possible for the handling device with the conveying lines, and/or the pile tube with the lines, to can be used not only for one but also for a plurality of feeds of curable suspension.

Particularly reliable filling of the annular space is achieved, according to a preferred method variant of the invention, in that at least one outlet opening is located in a lower region of the pile tube and the curable medium fills the annular space from the bottom to the top. Preferably, a plurality of outlet openings can also be arranged in a lower region of the pile tube. Outlet openings can also be purposeful arranged in a region of the pile tube located thereabove, which outlet openings may preferably not yet be opened by means of a valve means at the start of the filling, but are opened only in the course of the filling process, at defined timepoints.

An undesired flow in of the curable medium into the interior of the pile tube can be prevented or significantly restricted, according to a further development of the invention, in that an excess pressure is generated at least in the pile tube, in a lower portion, which excess pressure counteracts an entry of curable medium from the annular space into the interior of the pile tube. The excess pressure can in principle be generated in any suitable manner. It is particularly preferred, according to an embodiment of the invention, that a bulkhead plate is arranged in a lower portion of the pile tube, in order to form an excess pressure therein, which bulkhead plate seals off the lower portion from an upper portion located thereabove. The thereby resulting separation of the lower portion means that liquid inside the lower portion is enclosed therein and can no longer be displaced upwards. Thus, even a slight inflow of curable medium from below leads to a pressure increase in the lower portion, which counteracts a further inflow of curable medium into the pile tube.

In the case of use of a pile tube comprising a bulkhead plate, a preferred method variant consists in that at least one through-opening on the bulkhead plate is opened, for inserting the pile tube into a drilled hole filled with liquid. This ensures that, upon insertion of the pile tube, air or liquid is not enclosed in the lower portion, but can flow out freely upwards, through the bulkhead plate, upon insertion. Only after the end position has been reached, and in particular after the pile tube has been placed on the bottom of a drilled hole, the at least one through-opening on the bulkhead plate is closed, such that the lower portion is separated in a pressure-tight manner. In this state, the bulkhead plate brings about the advantageous function, described above, of preventing the undesired inflow of curable medium into the pile interior.

Accordingly, it is advantageous, according to a further variant of the invention, that the at least one through-opening is closed after placement of the pile tube on the bottom of a drilled hole and before introduction of the curable medium. This measure is expedient in particular if the foundation pile is placed under water, on the bottom of a body of water. The opening of the bulkhead plate by the through-opening thus also allows for rapid lowering of the pile tube into the body of water and into the drilled hole.

A further improvement of the production of the foundation pile results, according to an embodiment of the invention, in that for insertion of the pile tube into the drilled hole the handling device is coupled to a lifting equipment and that after introduction of the curable medium the lifting equipment is released from the handling device and the handling device remains on the pile tube as an extra load, at least until the medium has cured.

In particular, a support cable or a support rod on a crane can be used as the lifting equipment. In this case, the handling device is connected to the support cable or the support rod via a releasable connecting means, for example a crane hook.

After inserting the pile tube into the drilled hole, and introducing the curable medium into the annular space, the lifting equipment can be released from the handling device, while the handling device still remains on the pile tube. The handling device can thus serve as an additional extra load for fixing the pile tube in position, at least until the curable medium is sufficiently cured and the pile tube is thus fixed in its position.

A preferred further development consists in that after curing of the medium the handling device is released from the pile tube and is salvaged. For this purpose, it is possible to again use the lifting equipment with the releasable connecting means on a support cable or a support rod for salvaging the handling device. In this case, the handling device can comprise an energy-operated or mechanical clamping device, in particular for force-fitting connection to the pile tube. This connection can be released again for salvaging the handling device.

The method according to the invention makes it possible for a foundation pile to be erected in the ground at any desired and suitable location. In particular, the method can be implemented on land, wherein the pile tube is inserted into a drilled hole filled with liquid, in particular water. It is particularly advantageous, according to an embodiment of the invention, for the foundation pile to be erected under water, in a bottom of a body of water as the ground. The body of water can in particular be a river, a lake or a sea.

In particular drilled holes under water on a bottom of a body of water are more difficult to access than on land, and therefore reliable erection of a foundation pile can be performed, with the method according to the invention, even at greater depths of water.

In particular in the case of a lake or a river, the method can be carried out by means of a corresponding device from a shore. It is particularly expedient, according to a embodiment variant of the invention, for the handling device to be operated based upon a watercraft. The watercraft can in particular be a boat or a pontoon.

It is furthermore advantageous, according to a embodiment variant of the method according to the invention, for the handling device to be connected to at least one supply line via a releasable connecting means. Via the supply line, which is also referred to as the umbilical, a feed of the curable medium, as well as an energy supply, in particular of electrical, hydraulic and/or pneumatic energy, as well as a data transfer via corresponding data lines, can take place. The supply line can accordingly comprise a bundle of different lines and/or hoses.

The invention will be explained in greater detail in the following, with reference to preferred exemplary embodiments that are shown schematically in the drawings, in which show:

FIG. 1: a schematic sectional view of a pile tube comprising a bulkhead plate;

FIG. 2: a schematic view of a lower part of a pile tube in a drilled hole;

FIG. 3: a schematic detailed cross-sectional view of a feed device on the bulkhead plate of a pile tube; and

FIG. 4: a perspective view of a handling device for handling a pile tube.

According to FIG. 1, a pile tube 10 comprising a tubular main body 12 is provided. A bulkhead plate 20 directed transversely to the longitudinal axis of the tubular main body 12 is arranged in an inside region 13 of the tubular main body 12, which bulkhead plate divides the inside region 13 into a lower portion 14 and an upper portion 15 and separates these from one another. An annular sealing element 19 can be arranged at a lower edge of the tubular main body 12, by means of which sealing element the pile tube 10 can be placed as far as possible in a sealing manner on a bottom of a drilled hole.

In the exemplary embodiment shown, the bulkhead plate 20 comprises two through-openings 22 (indicated schematically), which can be opened or closed in a targeted manner by means of a closure device 24 (also shown schematically). A feed device 30 comprising two feed openings 32 (indicated schematically) each comprising an introduction funnel 34 is arranged in a central region of the bulkhead plate 20, as will be described in more detail in the following in connection with FIG. 3.

The feed openings 32 comprising the introduction funnels 34 serve for feeding a curable medium, in particular mortar or cement suspension, wherein the curable medium can be conducted underneath the bulkhead plate 20, via lines 26, as far as a lower end region of the tubular main body 12. In this case, the lines 26 extend through a tube wall 16 of the main body 12 and lead in each case, on an outer circumference 17 of the main body 12, into an outlet opening 28. Thus, curable medium can be conducted via an inside region 13 of the pile tube 10 as far as a lower end region, and can emerge to the outside of the pile tube 10 via the outlet openings 28, as is explained in more detail in the following in connection with FIG. 2.

FIG. 2 shows, schematically and not to scale, a lower end region of a pile tube 10 according to the invention, which is inserted into a drilled hole 4 in the ground 1. Only the lower region of the drilled hole 4 is shown, wherein the drilled hole 4 can have a depth of several metres, typically between 5 m and 30 m. The drilled hole 4 is filled, for support, with a liquid, in particular water or another supporting liquid, such that the drilled hole 4 does not collapse even in the case of greater drilled hole depths. A support tube can also be provided, at least in regions.

In a drilled hole 4 filled with liquid in such a way, it is possible to insert the pile tube 10 with a bulkhead plate 20 without problem, if the through-openings 22 on the bulkhead plate 20 are opened by the closure devices 24. After an end position of the pile tube 10 is reached, in particular when placing the pile tube 10 on a drilled hole bottom 5 of the drilled hole 4, the through-openings 22 can be closed again by the closure devices 24. Curable medium can now be introduced into the drilled hole 4 vial the lines 26, wherein the curable medium is fed inside the pile tube 10 in the lower region with the lines 26, and at the lower end region passes through the tube wall 16 and can emerge via the outlet opening 28 into an annular space 6. The annular space 6 is formed between an outer circumference 17 of the tubular main body 12 and a substantially cylindrical wall 8 of the drilled hole 4. In this case, the curable medium can fill the annular space 6 from the bottom to the top, due to a higher density compared with the liquid in the drilled hole 4. In this case, liquid is displaced upwards, out of the annular space 6, by the curable medium.

The provided bulkhead plate 20 seals a lower portion 14 of the inside region 13 of the pile tube 10 towards the top, in the case of closed through-openings 22. Thus, the liquid in the lower portion 14 of the pile tube 10 cannot be displaced upwards, such that also no or barely curable medium can penetrate into the inside region 13 of the pile tube 10. As a result, the inside region 13 can be reliably kept free, and curable medium or suspension can be saved.

According to FIG. 3, the feed device 30 of the pile tube 10 according to FIG. 1 is shown in more detail. The feed device 30 can comprise a pot-shaped receptacle 31, which is attached in a central region of the bulkhead plate 20. The feed openings 32 for the lines 26 leading away downwards are designed in the pot-shaped receptacle 31. For introduction of the curable medium, the feed openings 32 comprise introduction funnels 34 in their upper region. The feed openings 32 can furthermore be designed having non-return valves 36 (shown only schematically), which prevent an undesired return flow of the curable medium out of the lines 26 in the example shown.

For feeding the curable medium, according to the invention a handling device 50 according to FIG. 4 can be used. The handling device 50 comprises a main body 52 having a cover plate 54, on which an attachment element 58 for putting on or arranging the handling device 50 on top or on a pile tube is arranged.

In the exemplary embodiment shown, the handling device 50 can be releasably attached to an inside of the pile tube 10 with at least one clamping or gripping element 57, via a gripping device 56, which can alternatively or additionally also be configured as a force-fitting clamping device. Preferably, a plurality of gripping elements 57 is arranged along the circumference on the approximately tubular or barrel-shaped main body 52.

A pile tube 10 can be gripped already on a ground surface or a watercraft, from a pile tube store, by means of the handling device 50. The pile tube can be in any position when being gripped, for example can be arranged horizontally or vertically. The handling device can be connected to a lifting equipment, in particular a crane, via a holding element 55 on the upper end region of the main body 52. Thus, a pile tube 10 can be inserted, from a storage position, into a drilled hole 4 in the ground 1, by using the handling device 50.

Furthermore, the handling device 50 is provided with a feed device 60 (indicated only schematically) which, in the exemplary embodiment shown, comprises conveying lines 64 which extend from an inlet device 62 on the upper end of the main body 52 as far as a lower outlet device 66. The outlet device 66 is configured for coming into engagement on a pile tube 10 according to FIG. 3, for feeding a curable medium, via the introduction funnel 34 of the feed device 30. Furthermore, a corresponding coupling unit can be provided on the handling device 50, in order to ensure, in interaction with the coupling element 23 on the feed device 30 of the pile tube 10, exact positioning and positional stability.

Via a supply line 80, which can also be referred to as the umbilical, curable medium, energy and/or data can be fed via a releasable connecting device 70, wherein the curable medium is transferred to the inlet device 62 at the upper end region of the main body 52. An individual supply line can be provided, or also separate lines.

After the annular space 6 has been filled with the curable medium, the connecting line 80 and/or the lifting equipment can be released from the holding element 55, wherein the handling device 50 can remain as an additional extra load on the pile tube 10, at least until the curable medium for forming the foundation element in the ground 1 is cured. Subsequently, the handling device 50 can be released again from the pile tube 10 and be retrieved.