Method for forming a foundation pile in the ground

Abstract

The invention relates to a method for forming a foundation pile in the ground, in which a borehole is drilled in the ground, a pile pipe is gripped by means of a handling device and inserted into the borehole, and a curable medium is introduced into an annular space between a wall of the borehole and an outer circumference of the pile pipe, which hardens to form the foundation pile. According to the invention, the curable medium is introduced into the borehole via the handling device.

Description

[0001] The invention relates to a method for forming a foundation pile in the ground, particularly in a body of water, in which a borehole is created in the ground, a pile tube is gripped by a handling device and inserted into the borehole, and a hardenable medium is introduced into an annular space between a wall of the borehole and an outer circumference of the pile tube, which hardens to form the foundation pile. JP S50-42614 A discloses a method having the features of the preamble of claim 1.

[0002] EP 2 930 275 A1 discloses a method and an arrangement for producing a foundation pile for a structure in water. In this method, a borehole with a support pipe is first created in the ground. The resulting borehole is filled with a liquid, in particular water. A pile pipe, which consists of a simple steel pipe with a tubular base, is inserted into the cased borehole created in this way. The outer support pipe is then pulled out and the annular space between the inserted pile pipe, which stands on the bottom of the borehole, and the surrounding borehole wall is filled with a hardening medium. The surrounding water can remain within the pile pipe. The load-bearing capacity of the foundation pile created in this way is determined by the outer surface area of ​​the inserted pile pipe in relation to the surrounding soil with the hardened medium in the surrounding annular space.The interior, which is filled only with water, can be used, if necessary, to accommodate measuring or testing equipment.

[0003] WO 2021 / 180515 A1 discloses a device for handling and inserting a pile tube into a borehole. The device is designed for attachment to a crane's support cable. Gripping elements can be used to grip an annular edge of the pile tube in a force-locking manner. Overall, the device is designed so that the pile tube can be pivoted from a horizontal storage position to a vertical insertion position.

[0004] US 2010 / 0296875 A1 describes an arrangement and method for constructing an underwater foundation using an underwater drilling rig. The underwater drilling rig can be placed on a body of water. A foundation bore is created using tubular elements. The tubular elements can also serve to anchor the drilling device underwater.

[0005] In the known methods, after the pile tube has been inserted into a drilled borehole, the outer annular space between the outer surface of the pile tube and the surrounding borehole wall is filled. For this purpose, one or more supply hoses are introduced into the annular space, through which a hardenable medium, such as mortar or a cement suspension, is then introduced into the annular space. The hardenable medium should be introduced in such a way that the annular space is filled from below, so that any liquid, especially water, present in the annular space is displaced from bottom to top by the hardenable medium.

[0006] The hose is usually inserted into the annular space manually from outside the borehole. At borehole depths of 10 meters and more, the problem arises that a feed hose can get caught in a central section of the borehole and thus not reach the bottom of the borehole. This cannot usually be detected from outside the borehole. If the hardening suspension is fed into such an incorrectly inserted feed hose, liquid can remain in the annular space below the feed hose and be trapped by the hardening suspension above. In this case, a pile tube would not be connected to the surrounding soil over its entire length after the suspension has hardened. This reduces the load-bearing capacity of a correspondingly formed foundation element, meaning that a reliable foundation can no longer be guaranteed.

[0007] Reworking the foundation element may be necessary, which can be very time-consuming and costly. In some cases, it may even be necessary to rebuild the foundation element.

[0008] It is also known to provide a supply line for a hardenable suspension within the pile tube. The at least one supply line can then convey the hardenable medium within the pile tube to the lower region of the pile tube and, via corresponding passages, into the annular space outside the pile tube. With this method, a corresponding supply line for the hardenable suspension must be arranged after the pile tube has been inserted, either up to the passage into the annular space within the pile tube or to an upper connection on the pile tube. Creating such a connection is time-consuming and labor-intensive and also carries the risk of errors.

[0009] The invention is based on the Task The aim is to provide a method by which a foundation pile can be installed in the ground efficiently and reliably.

[0010] The object is achieved by a method having the features of claim 1. Preferred embodiments of the invention are specified in the dependent claims.

[0011] The method according to the invention is characterized in that the hardenable medium is introduced into the bore via the handling device.

[0012] A basic idea of ​​the invention is to use the handling device not only for gripping and inserting the pile tube into the borehole, but also for introducing the hardenable medium into the borehole. The handling device is not detached from the pile tube after the pile tube has been inserted into the borehole, but can remain in a defined initial position on the pile tube, which was assumed outside the borehole when the handling device gripped the pile tube. Due to the thus predetermined relative position between the pile tube and the handling device, a reliable supply of the hardenable medium can be achieved via the handling device.

[0013] A preferred embodiment of the invention consists in introducing the hardenable medium into the borehole while the pile tube is held by the handling device. The handling device can grip the pile tube in a storage position, in particular in a horizontal position, and thus preferably connect it force-fittingly. Thus, from the outset, there is a fixed relative position between the handling device and the gripped pile tube. A defined relative position between the pile tube and the handling device can be established. In this initial position, the hardenable medium can then be supplied to the pile tube after the pile tube has been inserted into the borehole.

[0014] According to a further development of the method according to the invention, it is preferred that the hardenable medium is conveyed by means of at least one conveying line through the handling device to at least one feed opening on the pile tube, wherein the hardenable medium is conveyed through the pipe 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 supplying the hardenable 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 permanently attached to the handling device or can be attached subsequently after the pile tube has been gripped.From the conveying line of the handling device, the hardenable medium is transferred via at least one feed opening on the pile tube. From the feed opening, it is guided 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 area. This ensures reliable supply of the hardenable medium to the lower area of ​​the annular space.

[0015] In principle, it is sufficient if a single delivery line is provided on the handling device and also only a single line on the pile tube for supplying the hardenable medium. To ensure long-term functionality, according to a further development of the invention, it is preferred that at least two delivery lines and / or lines are provided, which are switched by means of at least one valve device in such a way that they are connected in parallel to form a double feed or in series for flushing operation. If at least two lines are provided, a faster supply of the hardenable medium can take place. Furthermore, if two lines are arranged, a valve device can be provided in such a way that it can interconnect the two delivery lines on the handling device and / or the two lines on the pile tube in such a way that they are connected in series.Thus, a flushing fluid can be supplied via a first conveying line or pipe, and discharged via the second conveying line or pipe. This allows the conveying lines or pipes to be flushed and thus protected from blockage by hardened medium. This allows the handling device with the conveying lines and / or the pile tube with the pipes to be used not only for one, but also for multiple feeds of hardenable suspension.

[0016] 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 hardenable medium fills the annular space from bottom to top. Preferably, several outlet openings can also be arranged in a lower region of the pile tube. Outlet openings can also be arranged in a targeted manner in an overlying region of the pile tube. These outlet openings, if appropriate, are preferably not opened at the beginning of the filling process by means of a valve device, but are opened only at defined times during the filling process.

[0017] According to the invention, an undesired inflow of the hardenable medium into the interior of the pile tube can be prevented or significantly restricted by generating an overpressure at least in a lower section of the pile tube, which counteracts the entry of the hardenable medium from the annular space into the interior of the pile tube. The overpressure can, in principle, be generated in any suitable manner.

[0018] According to one embodiment of the invention, it is particularly preferred that, in order to create an overpressure in a lower section of the pile tube, a bulkhead plate is arranged therein, which seals off the lower section from an upper section located above it. The resulting sealing of the lower section results in liquid within the lower section being trapped therein and no longer being able to be displaced upwards. Thus, even a slight inflow of hardenable medium from below leads to a pressure increase in the lower section, which counteracts any further inflow of hardenable medium into the pile tube.

[0019] When using a pile tube with a bulkhead plate, a preferred method variant involves opening at least one through-hole in the bulkhead plate to insert the pile tube into a fluid-filled borehole. This ensures that air or fluid is not trapped in the lower section when the pile tube is inserted, but can flow freely upwards through the bulkhead plate. Only after the final position has been reached, and in particular when the pile tube has been placed on the bottom of the borehole, is the at least one through-hole in the bulkhead plate closed, so that the lower section is pressure-tightly sealed. In this state, the bulkhead plate performs the advantageous function described above of preventing the unwanted inflow of hardening medium into the interior of the pile.

[0020] Accordingly, according to a further variant of the invention, it is advantageous for the at least one through-opening to be closed after the pile tube has been placed on the bottom of the borehole and before the hardening medium is introduced. This measure is particularly useful when the foundation pile is installed underwater on a body of water. Opening the bulkhead plate through the through-opening also enables the pile tube to be lowered quickly into the body of water and into the borehole.

[0021] A further improvement in the production of a foundation pile results according to an embodiment of the invention in that for inserting the pile tube into the bore, the handling device is coupled to a lifting device and that after the introduction of the hardenable medium, the lifting device is released from the handling device and the handling device remains on the pile tube as a load, at least until the medium has hardened.

[0022] A lifting device can be used, in particular, as a support rope or a support rod on a crane. The handling device is connected to the support rope or support rod via a detachable connecting device, such as a crane hook.

[0023] After inserting the pile tube into the borehole and introducing the hardening medium into the annular space, the lifting gear can be detached from the handling device, while the handling device remains attached to the pile tube. The handling device can thus serve as an additional load to fix the pile tube in position, at least until the hardening medium has sufficiently hardened and the pile tube is secured in position.

[0024] A preferred development consists in that, after the medium has hardened, the handling device is detached from the pile tube and retrieved. For this purpose, the hoist with the detachable connection device can be used again on a support rope or a support rod to retrieve the handling device. The handling device can have a power-driven or mechanical clamping device, in particular for a force-locking connection to the pile tube. This connection can be released again to retrieve the handling device.

[0025] Using the method according to the invention, a foundation pile can be installed in the ground at any desired and suitable location. In particular, the method can be carried out on land, with the pile tube being inserted into a borehole filled with liquid, in particular water. According to one embodiment of the invention, it is particularly advantageous for the foundation pile to be installed underwater in the bed of a body of water. The body of water can, in particular, be a river, a lake, or the sea.

[0026] In particular, underwater drilling on the bottom of a body of water is more difficult to access than on land, so that the method according to the invention can be used to reliably construct a foundation pile even at greater water depths.

[0027] Especially in the case of a lake or river, the method can be carried out from a shore using a suitable device. According to one embodiment of the invention, it is particularly expedient for the handling device to be operated from a watercraft. The watercraft can, in particular, be a ship or a pontoon.

[0028] Furthermore, according to one embodiment of the method according to the invention, it is advantageous for the handling device to be connected to at least one supply line via a detachable connecting device. The supply line, also referred to as an umbilical, can be used to supply the curable medium and energy, in particular electrical, hydraulic, and / or pneumatic energy, as well as data transfer via corresponding data lines. The supply line can accordingly comprise a bundle of different lines and / or hoses.

[0029] The invention is further explained below with reference to preferred embodiments which are shown schematically in the drawings. In the drawings show: Fig. 1 shows a schematic sectional view of a pile tube with a bulkhead plate; Fig. 2 shows a schematic representation of a lower part of a pile tube in a bore; Fig. 3 shows a schematic detailed cross-sectional view of a feed device on the bulkhead plate of a pile tube; and Fig. 4 shows a perspective view of a handling device for handling a pile tube.

[0030] According to Fig. 1A pile tube 10 with a tubular base body 12 is provided. A bulkhead plate 20 is arranged in an inner region 13 of the tubular base body 12, directed transversely to the longitudinal axis of the tubular base body 12. This bulkhead plate 20 divides the inner region 13 into a lower section 14 and an upper section 15, separating them from each other. An annular sealing element 19 can be arranged on a lower edge of the tubular base body 12, with which the pile tube 10 can be placed on the bottom of a borehole in a manner that seals as tightly as possible.

[0031] In the illustrated embodiment, the bulkhead plate 20 has two schematically indicated through openings 22, which can be specifically opened or closed by means of a closure device 24, which is also schematically indicated. InIn a central region of the bulkhead plate 20, a feed device 30 is arranged with two schematically indicated feed openings 32, each with an insertion funnel 34, as will be described in more detail below in connection with Fig. 3 described.

[0032] The feed openings 32 with the feed funnels 34 serve to supply a hardenable medium, in particular mortar or cement suspension, wherein the hardenable medium can be guided below the bulkhead plate 20 via lines 26 to a lower end region of the tubular base body 12. The lines 26 extend through a pipe wall 16 of the base body 12 and each open at the outer circumference 17 of the base body 12 in an outlet opening 28. Thus, hardenable medium can be guided via an inner region 13 of the pile tube 10 to a lower end region and exit via the outlet openings 28 to the outside of the pile tube 10, as will be described in more detail below in connection with Fig. 2 is explained.

[0033] In Fig. 21 shows a schematic, not to scale, lower end region of a pile tube 10 according to the invention, which is inserted into a borehole 4 in the ground 1. Only the lower region of the borehole 4 is shown, whereby the borehole 4 can have a depth of several meters, typically between 5 m and 30 m. The borehole 4 is filled with a liquid, in particular water or another supporting liquid, for support, so that the borehole 4 does not collapse even at greater borehole depths. A support tube can also be provided at least in some areas.

[0034] The pile tube 10 with a bulkhead plate 20 can be easily inserted into a borehole 4 filled with liquid in this way if the through openings 22 on the bulkhead plate 20 are opened by the closure devices 24. After the pile tube 10 has reached an end position, in particular when the pile tube 10 is placed on a borehole bottom 5 of the borehole 4, the through openings 22 can be closed again with the closure devices 24. Hardenable medium can now be introduced into the borehole 4 via the lines 26, wherein the hardenable medium is supplied within the pile tube 10 in the lower region via the lines 26 and passes through the pipe wall 16 at the lower end region and can exit via the outlet opening 28 into an annular space 6. The annular space 6 is formed between an outer circumference 17 of the tubular base body 12 and a substantially cylindrical wall 8 of the borehole 4.Due to its higher density than the fluid in the bore 4, the hardenable medium can fill the annular space 6 from bottom to top. The fluid is displaced upwards from the annular space 6 by the hardenable medium.

[0035] The provided bulkhead plate 20 seals a lower section 14 of the interior 13 of the pile tube 10 upwards when the through-holes 22 are closed. Thus, the liquid in the lower section 14 of the pile tube 10 cannot be displaced upwards, so that no or hardly any hardenable medium can penetrate into the interior 13 of the pile tube 10. This allows the interior 13 to be reliably kept clear, and hardenable medium or suspension can be saved.

[0036] According to Fig. 3 the feeding device 30 of the pile tube 10 is Fig. 1shown in more detail. The feed device 30 can have a cup-shaped receptacle 31, which is mounted in a central region of the bulkhead plate 20. In The cup-shaped receptacle 31 contains the feed openings 32 for the downwardly leading lines 26. For introducing the curable medium, the feed openings 32 have inlet funnels 34 at their upper portion. The feed openings 32 can also be provided with check valves 36 (shown only schematically), which prevent unwanted backflow of the curable medium from the lines 26 in the illustrated example.

[0037] For supplying the curable medium, a handling device 50 according to the invention can be used Fig. 4The handling device 50 has a base body 52 with a cover plate 54, on which an attachment element 58 is arranged for placing or arranging the handling device 50 on or at a pile tube 10.

[0038] In the illustrated embodiment, the handling device 50 can be releasably attached to an inner side of the pile tube 10 with at least one clamping or gripping element 57 via a gripping device 56, which can alternatively or additionally be designed as a force-locking clamping device. Preferably, several gripping elements 57 are arranged along the circumference of the approximately tubular or barrel-shaped base body 52.

[0039] With the handling device 50, a pile tube 10 can be picked up from a pile tube storage facility on the ground surface or from a watercraft. The pile tube 10 can be positioned in any desired position during picking, for example, horizontally or vertically. The handling device 50 can be connected to a lifting device, in particular a crane, via a holding element 55 at the upper end region of the base body 52. ​​Thus, a pile tube 10 can be inserted from a storage position into a borehole 4 in the ground 1 via the handling device 50.

[0040] In addition, the handling device 50 is provided with a feed device 60, which is only schematically indicated and which, in the illustrated embodiment, has conveyor lines 64 which extend from an inlet device 62 at the upper end of the base body 52 to a lower outlet device 66. The outlet device 66 is designed to be connected to a pile tube 10 via the insertion funnels 34 of the feed device 30 according to Fig. 3 to engage the supply of a hardenable medium. Furthermore, a corresponding coupling unit can be provided on the handling device 50 to ensure precise positioning and positional security in cooperation with the coupling element 23 on the feed device 30 of the pile tube 10.

[0041] A supply line 80, which can also be referred to as an umbilical, can supply curable medium, energy, and / or data via a detachable connecting device 70, whereby the curable medium is transferred to the inlet device 62 at the upper end region of the base body 52. ​​A single supply line or separate lines can be provided.

[0042] After the annular space 6 has been filled with the hardenable medium, the connecting line 80 and / or the lifting gear can be detached from the holding element 55, whereby the handling device 50 can remain on the pile tube 10 as an additional load, at least until the hardenable medium has hardened to form the foundation element in the ground 1. The handling device 50 can then be detached from the pile tube 10 and retrieved.

Claims

1. Method for forming a foundation pile in the ground (1), in which - a drilled hole (4) is created in the ground (1), - a pile tube (10) is gripped by means of a handling device (50) and inserted into the drilled hole (4), and - a curable medium is introduced into an annular space (6) between a wall (8) of the drilled hole (4) and an outer circumference (17) of the pile tube (10), which medium cures to form the foundation pile, - wherein the curable medium is introduced into the drilled hole (4) via the handling device (50). characterised in that an excess pressure is generated at least in the pile tube (10) in a lower portion (14), which excess pressure counteracts an entry of curable medium from the annular space (6) into the interior of the pile tube (10).

2. Method according to claim 1, characterised in that the curable medium is introduced into the drilled hole (4), while the pile tube (10) is held by the handling device (50).

3. Method according to claim 1 or 2, characterised in that the curable medium is conducted by means of at least one conveying line (64) through the handling device (50) up to at least one feed opening (32) on the pile tube (10), wherein the curable medium is conducted via at least one line (26) through the tube wall (16) of the pile tube (10) and emerges into the annular space (6) via at least one outlet opening (28) on the outer circumference (17) of the pile tube (10).

4. Method according to claim 3, characterised in that two conveying lines (64) and / or lines (26) are provided, which are switched by at least one valve means in such a way that they are connected in parallel for forming a dual feed line or are connected in series for rinsing operation.

5. Method according to claim 3 or 4, characterised in that at least one outlet opening (28) is located in a lower region of the pile tube (10) and the curable medium fills the annular space (6) from the bottom to the top.

6. Method according to any one of claims 1 to 5, characterised in that in order to form an excess pressure in the lower portion (14) of the pile tube (10) a bulkhead plate (20) is arranged therein, which bulkhead plate seals off the lower portion (14) from an upper portion (15) located above.

7. Method according to claim 6, characterised in that for inserting the pile tube (10) into a drilled hole (4) filled with liquid, at least one through-opening (22) on the bulkhead plate (20) is opened.

8. Method according to claim 7, characterised in that the at least one through-opening (22) is closed after the pile tube (10) has been placed on a drilled hole bottom (5) and before the curable medium is introduced.

9. Method according to any one of claims 1 to 8, characterised in that for inserting the pile tube (10) into the drilled hole (4) the handling device (50) is coupled to a lifting equipment, and in that after the introduction of the curable medium the lifting equipment is released from the handling device (50) and the handling device (50) remains on the pile tube (10) as an extra load, at least until the medium is cured.

10. Method according to claim 9, characterised in that after the curing of the medium the handling device (50) is released from the pile tube (10) and is salvaged.

11. Method according to any one of claims 1 to 10, characterised in that the foundation pile is created under water in a bottom of a body of water as the ground (1).

12. Method according to any one of claims 1 to 11, characterised in that the handling device (50) is actuated based upon a watercraft.

13. Method according to any one of claims 1 to 12, characterised in that the handling device (50) is connected via a releasable connecting device (70) to at least one supply line (80).

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