Foundation pile, pile foundation, and method for installing a foundation pile in the ground

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of foundation, and specifically relates to a foundation pile, pile foundation, and a method for installing a foundation pile into the ground.BACKGROUND OF THE INVENTION

[0002] The invention relates to a foundation pile comprising an elongated body, having a screw thread extending helically at least along part of the outer surface of the body, and a cavity extending at least over a considerable part of the length of the body and coaxially therewith.

[0003] The known foundation piles are driven into the ground by a rotatably driven element called a Kelly bar, which is arranged in the cavity of the pile and engages an inner part of the pile for transferring the rotational forces to the pile.

[0004] The individual piles may be manufactured in different lengths according to the depth required at a construction site.

[0005] In the past it was therefore generally necessary to produce such prefabricated pillars in many different lengths in order to have pillars of the necessary length available for a particular application.

[0006] In more resent years, it is known to join a number of concrete piles, typically two concrete piles, in order to achieve a necessary desired length. Such screw-threaded concrete piles are manufactured having a metal bracket on each concrete pile at the connecting ends. The metal brackets are then welded together to complete the interconnection.

[0007] When such screw-threaded piles, e.g., two interconnected piles, are to be installed into the ground, the first pile is driven into the ground by a Kelly bar in a known manner, until the upper end of the pile projects typically approximately half a meter above the ground surface. The second pile is lifted into position on top of the first pile and the abutting metal brackets of each concrete pile are welded together. Thereafter, the Kelly bar may be arranged extending down through both the first and second piles in order to drive the interconnected piles further into the ground.

[0008] The first and second piles are inside the inner cavity arranged with a longitudinal groove, preferably two internal longitudinal grooves, which cooperate with corresponding longitudinal projections in the Kelly bar, such that the rotational forces of the Kelly bar can be transferred to both the piles.

[0009] During welding of the two piles it is extremely important that the longitudinal grooves of the concrete piles are aligned to a certain degree; otherwise, the projections of the Kelly bar cannot engage the grooves of the first (lower) concrete pile when the Kelly bar is to be lowered into engagement with both piles.

[0010] Such an alignment is time consuming, and as the welding takes time, there is a great risk that the two interconnected piled are not properly aligned, and the interconnected piles may need to be disconnected from each other again.

[0011] Any misalignment may increase the risk of installation failure or a later foundation failure, which may in the worst case cause the overlying structure or the foundation it-self to collapse.

[0012] WO2015026223A1 discloses a pile foundation coupling having two identical coupling halfs which when mated together defines 45 degree angled square openings between flanges facing flanges. When the couplings are mated, pins (3) interlock the two couplings together such that the elements cannot move in relation to each other. By inserting the square pins into the square openings, the two couplings are jammed and cannot move after the half have been locked together. GB1216698A discloses another solution of a coupling, where coupling elements after mating can be locked in a longitudinal and circumferential direction.

[0013] There is therefore a need for arranging interconnected concrete piles where the interconnecting process is fast and the risk of misalignment is eliminated.

[0014] It is an object of the present invention to provide a foundation pile, a pile foundation, a coupling element and a method for installing a foundation pile into the ground which overcomes the above-defined problems.

[0015] The above object and advantages, together with numerous other objects and advantages, which will be evident from the description of the present invention, are according to a first aspect of the present invention obtained by: A foundation pile for installation into the ground, comprising an elongate body and a screw thread element extending helically at least along part of the outer surface of the body, the foundation pile comprising a coupling element, at least at one end of the elongated body, the coupling element comprising a base plate having a first surface facing the end of the elongated body, and a second surface defining an end surface of the foundation pile, the coupling element further comprising at least one male coupling extending from the second surface, and / or at least one female coupling comprising an opening in the base plate and into the respective end part of the body, the male coupling and the female coupling are dimensioned such that when the male coupling and / or the female coupling engages a corresponding male and / or female coupling of another foundation pile as defined, the engaged couplings are able to move in relation to each other between two end positions in a circumferential direction around a longitudinal center axis of the engaged foundation piles, the foundation pile comprises locking means for locking the foundation pile to another foundation pile in the longitudinal direction, such that when the male coupling and / or the female coupling engages a corresponding male and / or female coupling of the other foundation pile, the engaged couplings are able to be locked to each other and able to move in relation to each other between said two end positions while being locked in the longitudinal direction.

[0016] The foundation pile is manufactured from concrete and comprises a screw thread element extending helically at least along part, preferably the main part, of the outer surface of the body near the ends thereof.

[0017] For permitting the pile to be connected to another similar concrete pile, a coupling element is provided at an end of the pile. The foundation pile may comprise a coupling element at one end, and a tapered shape at the other end, where the tapered shape is arranged to be the end first driven into the ground.

[0018] In an alternative embodiment, the foundation pile comprises coupling elements at both ends, such that the "lower" end can be connected to a pile having tapered shape at one end and a coupling element at the other end.

[0019] The coupling element is preferably cast into the pile during manufacture of the pile it-self and comprises longitudinal reinforcing elements extending within and in the longitudinal direction of the foundation pile. The piles are factory-cast and subsequently delivered to the installation site. The coupling element comprises a substantially flat base plate for defining a substantially flat and stable front surface being the contact area between the two opposing piles. In this way the weight resting on the pile will be distributed over the complete surface of the base plate. The internal reinforcing elements prevent any substantial movement of the base plate, both during and after installation. The periphery of the base plate should be substantially concurrent with the end periphery of the pile for allowing a stable and secure foundation and proper weight distribution. Opposing base plates should be aligned to transfer the weight of the overlying structures downwardly.

[0020] The coupling element and the reinforcing element are preferably manufactured from iron or an iron alloy such as steel. The coupling element and the reinforcing element may be connected, such as by welding, to the reinforcing of the concrete pile.

[0021] The coupling element is arranged such that the male coupling and the female coupling are dimensioned such that when the coupling element engages a corresponding coupling element of another foundation pile substantially as defined, the engaged couplings are able to move in relation to each other in a circumferential direction around a longitudinal center axis of the engaged foundation piles.

[0022] The circumferential dimension of the opening of the female coupling is made larger than the circumferential dimension of the male coupling. It is hereby possible to rotate two pile foundations in relation to each other, even though the couplings are engaged. It is hereby possible to correct any misalignment between the longitudinal internal grooves of two foundation piles after they have been connected.

[0023] Arranging the coupling element with locking means, such as the above-defined openings extending through the male and female couplings, the apertures in the flange and the locking pin, it is achieved that two foundation piles can be locked to each other in the longitudinal direction while still being able to move freely between the two end positions in a circumferential direction around a longitudinal center axis of the engaged foundation piles. It is thus possible to regulate the position of the longitudinal internal grooves of two foundation piles in relation to each other, while still ensuring that the piles are locked to each other in the longitudinal direction.

[0024] According to a further embodiment of the first aspect of the invention, the elongated body comprises a hollow cavity defined by an inner wall extending in the longitudinal direction of the body, the inner wall having a groove extending in the longitudinal direction.

[0025] In order to drive the foundation pile into the ground with suitable piling equipment, such as a Kelly bar, the inner wall of the foundation pile comprises a groove, and preferably two grooves. Arranging the inner wall of the pile with grooves has the effect that a corresponding projection of the piling equipment can engage the grooves and rotate the foundation pile into the ground.

[0026] According to a further embodiment of the first aspect of the invention, the couplings are able to move in relation to each other in a circumferential direction around a longitudinal center axis of the engaged foundation piles, up to approximately 30 degrees, such as up to approximately 20 degrees.

[0027] It is preferred that the foundation piles are able to move in relation to each other in a circumferential direction around a longitudinal center axis of the engaged foundation piles, up to approximately 30 degrees, such as up to approximately 20 degrees. Experiments by the applicant have shown that the above-defined degree of movement provides a high degree of adjustment possibilities while still providing a strong connection between the two couplings.

[0028] According to a further embodiment of the first aspect of the invention, the coupling element comprises a support flange extending from a periphery of the base plate, perpendicular to the first surface and towards the elongated body, the support flange comprising an aperture at a specific distance from the first surface, and said male coupling comprising a first opening extending through the male coupling in a radial direction of the elongated body, and / or said female coupling comprising a second opening extending through the female coupling in a radial direction of the elongated body and being in connection with the aperture of the flange, the male coupling having a dimension in the circumferential direction being smaller than the dimension of the receptor cavity in the circumferential direction, the first opening having a larger dimension in the circumferential direction than the dimension of the second opening in the circumferential direction.

[0029] The support flange prevents any substantial movement of the base plate, both during and after installation.

[0030] Further, the support flange comprises an aperture being in connection with an opening arranged in the female coupling, such that a locking element, such as a pin, can be inserted from the outside and through the opening of the flange and into the opening of the female coupling.

[0031] The male coupling further comprises an opening arranged such that when the male coupling is inserted into a female coupling, the opening of the male coupling is in connection with the opening of the female coupling, and the pin can be inserted through the opening of the male coupling.

[0032] The opening of the male coupling has a dimension in the circumferential direction (of the foundation pile) which is larger than the circumferential dimension of opening of the female coupling. It is hereby possible to rotate two interconnected and locked foundation piles in relation to each other in order to align the longitudinal grooves.

[0033] According to a further embodiment of the first aspect of the invention, the groove is a dovetail groove.

[0034] The groove comprises a dovetail shape, such that the sidewalls of the grooves extend in a radial direction of the foundation pile, the radial direction being substantial perpendicular to the circumferential direction of the foundation pile (see the explanation in relation to figure 7). The projecting element of the Kelly bar comprises a surface corresponding the direction of the radial side walls of the grooves, such that the engagement surface of the projecting element is substantially flush with the side walls of the grooves. The driving forces from the Kelly bar are hereby transferred to the foundation pile in a direction that corresponds to the circumferential direction of the foundation pile. It is hereby prevented that the foundation pile may crack due to the extreme forces that need to be transferred into the foundation pile.

[0035] According to a further embodiment of the first aspect of the invention, the foundation pile comprises between 2-12 male couplings and between 2-12 female couplings.

[0036] As described above, the forces needed to drill the foundation pile into the ground are extreme. Further, the foundation piles may come in different lengths, and may also have different diameters, whereby is the necessary to arrange the foundation piles with a number of male and female coupling elements. It is obvious that the coupling elements must comprise a number of female couplings corresponding to the number of male couplings. Foundation piles having a larger diameter compared to smaller-sized piles may have up to 12 male couplings and female couplings, while smaller-sized foundation piles may comprise only two of each type of coupling.

[0037] In an alternative embodiment, the coupling comprises only one male and one female coupling.

[0038] According to a second aspect of the present invention, the above objects and advantages are obtained by: A pile foundation comprising at least two foundation piles according to any of the embodiments of the first aspect the invention.

[0039] The pile foundation comprises two foundation piles, each pile being arranged with a coupling element, such that the entire pile foundation can be drilled into the ground, with piling equipment, such as a Kelly bar, and where any misalignment of the internal grooves of the foundation piles is avoided.

[0040] According to a third aspect of the present invention, the above objects and advantages are obtained by: A pile foundation comprising a foundation pile according to the invention, and a pile foundation element having a tapered shape and defining the lowermost part of the foundation when installed into the ground, the pile foundation element comprising an end for facing and interconnection with the foundation pile, the end of the pile foundation element comprising male and / or female couplings corresponding to the male and / or female couplings of the foundation pile.

[0041] In order to easily establish the first penetration of the foundation pile through the ground, and the subsequent drilling of the pile into the ground, the pile foundation comprises a pile foundation element having a tapered shape. The tapered pile foundation element comprises a coupling element corresponding to the coupling element of the foundation pile.

[0042] It is thus possible to manufacture only one type of foundation piles, where such pile can be connected to both another similar foundation pile and a tapered foundation pile segment.

[0043] According to a further embodiment of the third aspect of the invention, the pile foundation comprises a second foundation pile according to any of the embodiments of the first aspect of the invention.

[0044] The pile foundation further comprises a second foundation pile corresponding to the first foundation pile, whereby the length of the pile foundation is increased.

[0045] According to an aspect not according to the present invention, the above objects and advantages are obtained by: A coupling element for use in a foundation pile according to any of the embodiments of the first aspect of the invention, the coupling element comprising a base plate having a first surface for facing the end of the elongated body and a second surface for defining an end surface of the foundation pile, the coupling element further comprising at least one male coupling extending from the second surface, and / or at least one female coupling comprising an opening in the base plate.

[0046] The above aspect not according to the invention, defines a coupling element for casting into an elongated screw-threaded concrete body in order to arrange a foundation pile according to any of the embodiments of the first aspect of the invention.

[0047] The coupling element is preferably manufactured from iron or an iron alloy, such as steel, and is arranged such that the coupling element and reinforcing elements inside the elongated concrete may be connected before casting, e.g., by welding.

[0048] According to a further embodiment not according to the invention the invention, the coupling element comprises at least one reinforcement bar for protruding into said pile from said rear surface and integrally cast into said pile.

[0049] In order to promote the interconnection between the coupling element and the reinforcing elements of the elongated concrete body, the coupling element comprises at least one reinforcing bar for extending in the longitudinal direction of the elongated concrete body and for interconnection, e.g., by welding to the reinforcing elements of the concrete body. The at least one reinforcing bar is also preferably manufactured from iron or an iron alloy such as steel.

[0050] According to a fourth aspect of the present invention, the above objects and advantages are obtained by: A method for installing a foundation into the ground, said method comprising the following steps: arranging a first foundation pile according to any of the embodiments of the first aspect of the invention, arranging piling equipment for driving the pile into said ground, engaging the foundation pile with the piling equipment, driving the foundation pile a predetermined distance into the ground, removing the piling equipment, arranging a second pile according to any of the embodiments of the first aspect of the invention, on top of said first foundation pile and connecting the engaged coupling elements of said first and second pile, arranging the piling equipment through the first and second foundation pile, and driving the second foundation pile into said ground.

[0051] The above-defined method provides a strong pile foundation in which it is possible to rotate the two piles in relation to each other in case of any misalignment between the internal grooves of the two piles, and hereby overcomes the above-defined problems associated with conventional foundation piles.

[0052] According to a further embodiment of the fourth aspect of the invention, the step of arranging the piling equipment through the first and second foundation pile comprises the step of arranging the piling equipment through the second pile, and before arranging the piling equipment through the first pile, rotating the piling equipment such that the first and second pile are arranged positioned, such that the grooves of the first and second piles, respectively, are aligned.

[0053] The above-defined method defines the possibility of regulating the position between two misaligned foundation piles, such that the internal grooves of the two piles are aligned, and the Kelly bar can extend through both piles.

[0054] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The invention may however be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout. Like elements will thus not be described in detail with respect to the description of each figure. Fig. 1 is a perspective view of a pile foundation. Fig. 2 is a perspective view of a pile foundation. Fig. 3 is a perspective view of a pile foundation. Fig. 4 is a cross section of a perspective view of a pile foundation. Fig. 5 is a cross section of a perspective view of a pile foundation. Fig. 6 is a cross section of a pile foundation. Fig. 7 is a cross section of a foundation pile and a Kelly bar.

[0055] Fig. 1 is a perspective view of a pile foundation comprising two foundation piles 10. Each foundation pile 10 comprises an elongated concrete body having an external screw thread 36 for drilling the pile foundation into the ground (not shown).

[0056] Figure 1 shows a lower part and the upper part of the similar foundation piles 10, where the lower and upper ends comprise corresponding coupling elements 12. Each coupling element 12 comprises a base plate 14 which is substantially planar and establishes the abutment surface between the two foundation piles 10.

[0057] Each coupling element 12 further comprises a number of male couplings 18 and a number of female couplings 20. In the shown embodiment, the coupling elements 12 comprises three male couplings 18 and three female couplings, such the that each type of coupling may connect to the different type of coupling of the other foundation pile 10. The coupling elements 12 further comprises a support flange for preventing any substantial movement of the base plate in relation to the concrete body, both during and after installation.

[0058] The screw thread 36 preferably extends along the most part of the concrete body but terminates in proximity of the support flange.

[0059] The support flange 16 comprises a number of flange openings 22 corresponding to the number of female couplings 20. The female couplings comprise an opening (not shown) extending coaxial with the flange opening, such that when a locking element such as a locking pin 34 is inserted through the flange opening 22, the pin extends through the female coupling 20.

[0060] The male couplings 18 are arranged to be inserted into the female couplings of the opposing coupling element 12 and are dimensioned such that the circumferential dimension (in relation to the foundation pile) of the male coupling 18 is smaller than the corresponding circumferential dimension of the female coupling 20. After the two coupling elements 12 have been joined, the two foundation piles are able to rotate in relation to each other around a center axis extending through the piles in the longitudinal direction thereof. The position of the internal grooves 30 of the two foundation piles may thus be corrected, such that a Kelly bar (not shown) can be positioned extending through both foundation piles.

[0061] As can be seen from figure 1, each male coupling 18 comprises a coupling element opening 24 which is arranged as an elongated hole. The elongated hole has a largest diameter which is larger than the largest diameter of the flange opening. This gives the possibility of regulating the mutual position of the two foundation piles 10 even though the two coupling elements 12 are joined and locked by the pin 34 in relation to each other.

[0062] Fig. 2 is a perspective view of a pile foundation comprising two foundation piles 10. The two foundation piles correspond to the foundation piles 10 illustrated in relation to figure 1. In figure 2, a first (lower) foundation pile has been driven into the ground (not shown) such that the upper end of the foundation pile 10 terminates a predefined distance above the ground level, such as approximately half a meter above ground level. The second (upper) foundation pile 10 has been lowered on top of the first foundation pile 10 such that the coupling elements 12 of the two foundation piles 10 interconnect and the flange openings 22 automatically align with the coupling element openings, such that locking elements, such as pins 34, can be inserted through the openings 22, 24 and lock the two foundation piles 10 in relation to each other in the longitudinal direction of the foundation piles 10.

[0063] Fig. 3 is a perspective view of a pile foundation comprising the two foundation piles 10 shown in relation to figure 1 and 2. In figure 3, the pins 24 have been inserted through the flange openings and through the coupling element openings, whereby the two foundation piles 10 are locked in relation to each other in the longitudinal direction thereof. The pile foundation is in the shown illustration ready for the Kelly bar to extend from the upper end of the second foundation pile, down through the pile 10, and further down into the first (lower) foundation pile. Hereby the internal grooves are aligned, and the entire pile foundation can be driven into the ground.

[0064] Fig. 4 is a cross section of a perspective view of a pile foundation. The figure illustrates a cross section of the foundation piles 10 shown in figure 1, where a first (lower) pile is driven into the ground a predetermined distance, and the second (upper) foundation pile 10 is being lowered towards the first foundation pile 10.

[0065] The figure clearly shows flange openings 22 arranged in both coupling elements 12 in relation to the female couplings 20. The flange opening 22 and the associated female coupling together establishes a channel suitable for the locking pin 34 to extend through the flange opening and into the female coupling where it is secured in the longitudinal direction of the piles 10. In order to lock the pin 34 inside the female coupling, the pin may be arranged with a locking feature (not shown), such as a locking ring arranged in a groove, e.g., at the pointy end of the pin, which locking ring engages a corresponding locking feature (not shown), such as a projection, inside the female coupling 20. The pins 34 are hereby securely arranged in connection with the flange openings 22 and the female couplings 20.

[0066] The male couplings 18 are shown with elongated coupling element openings 24 which are arranged elongated in the circumferential direction of the piles 10. The elongated shape of the coupling element openings provides the possibility of still being able to align the grooves 30 of the two foundation piles even though the two foundation piles are joined and locked to each other.

[0067] Fig. 5 is a cross section of a perspective view of a pile foundation. The figure illustrates a cross section of a part of the embodiment shown in figure 2. In figure 5, the second (upper) foundation pile has been lowered onto the upper end of the first (lower) foundation pile 10 such that the male couplings 18 are inserted into the female couplings 20. The pins 34 are inserted from outside through the flange openings 22 and into engagement with the female coupling 20 and the coupling element opening 24 of the male coupling 18. The longitudinal grooves 30 of the two foundation piles 10 are shown aligned, and therefore no further rotational adjustment of the two foundation piles 10 in relation to each other is necessary. However, in a situation where the two longitudinal channels 30 are not properly aligned, the second (upper) foundation pile needs to be rotated in relation to the first (lower) foundation pile 10.

[0068] Fig. 6 is a cross section of a pile foundation, through the second (upper) foundation pile 10 in figure 5 along line A-A. For the sake of simplicity, the screw thread of the pile foundations has not been shown. The angular rotation B shows that the first (lower) foundation pile 10 and the second (upper) foundation pile 10 have been rotationally displaced in relation to each other, and the grooves 30 are therefore not correctly aligned such that a Kelly bar 26 can be arranged through the junction between the two foundation piles 10.

[0069] The figure shows the edge 30' of the groove 30 of the first (lower) foundation pile 10, and hereby the grooves 30 being displaced in relation to each other such that it is not possible to install the Kelly bar 26. In order for the Kelly bar 26 to be installed across the junction between the two piles 10, the second (upper) foundation pile 10 needs to be rotated in the counter-clockwise direction.

[0070] Fig. 7 is a cross section of a foundation pile 10 and a Kelly bar 26. For the sake of simplicity, the screw thread of the pile foundations has not been shown. The figure shows a Kelly bar 26 extending through a foundation pile 10 and exerting a rotational force to the foundation pile, as indicated by the arrows.

[0071] The groove 30 comprises a dovetail shape, whereby the sidewalls of the grooves 30 extend in a radial direction of the foundation pile, the radial direction being substantially perpendicular to the circumferential direction of the foundation pile. The projecting element 32 of the Kelly bar 26 comprises engagement surfaces corresponding to the direction of the radial side walls of the grooves 30, such that the engagement surface of the projecting element 32 is substantially flush with the side walls of the grooves 30. The driving forces from the Kelly bar 26 are hereby transferred to the foundation pile in a direction that corresponds to the circumferential direction of the foundation pile indicated by the arrows. It is hereby prevented that the foundation pile may crack due to the extreme forces that need to be transferred into the foundation pile.

[0072] In the following is given a list of reference signs that are used in the detailed description of the invention and the drawings referred to in the detailed description of the invention. 10Foundation pile 12Coupling element 14Base plate 16Support flange 18Male coupling 20Female coupling 22Flange opening 24Coupling element opening 26Kelly bar 28Hollow cavity 30Groove 30'Groove edge 32Kelly bar projection 34Pin 36Screw thread

Claims

1. A foundation pile (10) for installation into the ground, whereby said foundation pile (10) comprises an elongate body and a coupling element (12), said coupling element (12) being at least at one end of said elongated body, said coupling element (12) comprising a base plate (14) having a first surface facing said end of said elongated body and a second surface defining an end surface of said foundation pile (10), said coupling element (12) further comprising at least one male coupling (18) extending from said second surface, and / or at least one female coupling (20) comprising an opening in said base plate (14) and into the respective end part of said body, wherein, said male coupling (18) and said female coupling (20) are dimensioned such that when said male coupling (18) and / or said female coupling (20) engages a corresponding male and / or female coupling (18, 20) of another foundation pile (10) as defined, said engaged couplings (18, 20) are able to move in relation to each other between two end positions in a circumferential direction around a longitudinal center axis of the engaged foundation piles (10), characterized in that, a screw thread (36) element extends helically at least along part of the outer surface of said body and in that said foundation pile (10) comprises locking means (34) for locking said foundation pile (10) to another foundation pile (10) in the longitudinal direction, such that when said male coupling (18) and / or said female coupling (20) engages a corresponding male and / or female coupling (18, 20) of the other foundation pile (10), said engaged couplings are able to be locked to each other and able to move in relation to each other between said two end positions while being locked in said longitudinal direction.

2. A foundation pile (10) according to claim 1, wherein said elongated body comprises a hollow cavity (28) defined by an inner wall extending in the longitudinal direction of said body, said inner wall having a groove (30) extending in said longitudinal direction.

3. A foundation pile (10) according to claim 1, where said couplings (18, 20) are able to move in relation to each other in a circumferential direction around a longitudinal center axis of said engaged foundation piles (10), up to approximately 30 degrees, such as up to approximately 20 degrees.

4. A foundation pile (10) according to any of claims 1-3, wherein said coupling element (12) comprises a support flange (16) extending from a periphery of said base plate (14), perpendicular to said first surface and towards said elongated body, said support flange (16) comprising an aperture (22) at a specific distance from said first surface, and said male coupling (18) comprising a first opening (24) extending through said male coupling (18) in a radial direction of said elongated body, and / or said female coupling (20) comprising a second opening extending through said female coupling (20) in a radial direction of said elongated body and being in connection with said aperture (22) of said flange, said male coupling (18) having a dimension in said circumferential direction being smaller than the dimension of the receptor cavity in said circumferential direction, said first opening (24) having a larger dimension in said circumferential direction than the dimension of said second opening in said circumferential direction.

5. A foundation pile (10) according to any of claims 1-4, wherein said groove (30) is a dovetail groove.

6. A foundation pile (10) according to any of claims 1-5, wherein said foundation pile (10) comprises between 2-12 male couplings (18) and between 2-12 female couplings (20).

7. A pile foundation comprising at least two foundation piles (10) according to any of claims 1-6.

8. A pile foundation comprising a foundation pile (10) according to any of claims 1-6, and a pile foundation element having a tapered shape and defining the lowermost part of the foundation when installed into the ground, said pile foundation element comprising an end for facing and interconnection with said foundation pile (10), said end of said pile foundation element comprising male and / or female couplings (18, 20) corresponding to said male and / or female couplings (18, 20) of said foundation pile (10).

9. A pile foundation according to claim 8, comprising a second foundation pile (10) according to claim 1-6.

10. A method for installing a foundation into the ground, said method comprising the following steps: • arranging a first foundation pile (10) according to any of claims 1-6, • arranging piling equipment for driving said foundation pile (10) into said ground, • engaging said foundation pile (10) with said piling equipment, • driving said foundation pile (10) a predetermined distance into said ground, • removing said piling equipment, • arranging a second foundation pile (10) according to any of claims 1-6 on top of said first foundation pile (10), connecting said engaged coupling elements (12) of said first and second foundation pile (10), • arranging said piling equipment through said first and second foundation pile (10), and • driving said second foundation pile (10) into said ground.

11. A method according to claim 10, wherein the step of arranging said piling equipment through said first and second foundation pile (10) comprises the step of: • arranging said piling equipment through said second foundation pile (10), • before arranging said piling equipment through said first foundation pile (10), rotating said piling equipment such that said first and second foundation pile (10) are arranged such that said grooves (30) of said first and second foundation piles (10), respectively, are aligned.