EP2796620A2 - Method for constructing a foundation pile for offshore constructions and foundation pile for offshore structures - Google Patents

Abstract

The application relates to a method for producing a foundation pile for offshore structures, the method comprising the following method steps:
Providing and arranging a drop anchor at a predetermined height above the seabed,
Attaching at least one flexible tension element to the fall anchor,
Attaching at least one potting grounding line to the tension element,
- Throwing down the drop anchor so that it penetrates into the seabed, and
- Introducing a curable potting compound in the shot channel generated by the fall anchor in the penetration into the seabed.

Description

The invention relates to a method for producing a foundation pile for offshore structures. The invention further relates to a foundation pile for offshore structures and an offshore structure with a pile foundation.

Offshore structures in the context of the present invention are, for example, wind turbines, substations or drilling or production platforms.

For certain foundation types for offshore structures, in particular for offshore wind turbines, a pile foundation in the seabed is required. Common foundation types are for example so-called monopiles, jackets, tripods or tripiles. To anchor these foundations in the seabed, one or more steel piles are first driven into the seabed. For example, a steel grid structure / steel tube structure is placed on the steel piles in the case of a jacket foundation, which receives a so-called "transition piece" above the sea level. The transition piece then takes on the actual structure, for example in the form of a steel tower. The tower receives at its uppermost end the wind power generator with a rotor.

The ramming of foundation piles, also referred to as "piles", is associated with noise emissions, which are undesirable in particular because they cause damage and behavioral disturbances of marine mammals. It is therefore known and sometimes required to carry out deterrent measures and / or noise abatement measures before carrying out pile driving to ensure that no marine mammals are in the vicinity of the pile work and / or that the sound is reduced to the permitted limit.

Since the depth of penetration of the rammed steel piles and the progress of such pile work depends on the strength of the seabed, this is Setting steel piles suffers from the disadvantage that the piles of a foundation placed on several piles are not always anchored with the same depth of penetration in the seabed.

Depending on the nature of the seabed, the piles must be driven with considerable depth into the seabed, as the stability of the piles is only ensured if the piles have been driven into the ground to a sustainable soil horizon. Under certain circumstances, the actual load of the piles may be higher than the assumed load bearing requirements, which may ultimately result in the failure of a foundation pile. Under certain circumstances, the load and material fatigue caused by the piling process can exceed the predicted and calculated amount, so that the pile must either be completely abandoned or has a reduced life expectancy. The danger of a local structural failure, for example due to dents, increases with greater depth of foundation.

Connecting the underwater constructions of the foundation to the foundation piles requires potting the compound with water curable potting compounds or other expensive bonding techniques.

The piles have to be set at a specified distance, which is ensured by means of the template in the so-called "prepiling". This presupposes that the ground condition is such that all piles to be set can be driven to the given soil horizon. There are no variations with regard to the distance or the place for setting the piles.

When placing larger piles, undersea currents can lead to the seabed bottoming out in the area of the piles. In that case, further measures must be taken to prevent the bottom of the sea from being cleared.

The invention is therefore based on the object to provide a particularly simple method for producing a foundation pile for offshore structures, which in particular is not subject to the aforementioned limitations.

• Bereitstellen und Anordnen eines Fallankers in einer vorbestimmten Höhe oberhalb des Meeresbodens,
• Befestigen wenigstens eines flexiblen Zugelements an dem Fallanker,
• Befestigen wenigstens einer Vergussmasseleitung an dem Zugelement,
• Abwerfen des Fallankers, so dass dieser in dien Meeresuntergrund eindringt und
• Einbringen einer aushärtbaren Vergussmasse in den von dem Fallanker bei dem Eindringen in den Meeresuntergrund erzeugten Schusskanal.

The object is achieved by a method for producing a foundation pile for offshore structures, comprising the following method steps:

• Providing and arranging a drop anchor at a predetermined height above the seabed,
• Attaching at least one flexible tension member to the fall anchor,
• Attaching at least one potting grounding line to the tension element,
• Throwing the fall anchor so that it penetrates into the seabed and
• Introducing a hardenable potting compound into the firing channel created by the pincers during penetration into the seabed.

As a shot channel in the context of the present invention, the displacement channel generated by the fall anchor when immersed in the sediment of the seabed is called.

The invention is based on the idea of using at least one anchor point in the seabed by means of a drop anchor and at least one anchored to the anchor anchor anchor at the anchorage on which the anchorage trunk is posted.

The fall anchor is dimensioned, for example, in terms of its mass and in terms of its geometry so that it penetrates due to its kinetic energy in free fall to a predetermined depth in the seabed. This takes in the case of this battered anchor trunk. One or more potting ground lines can be fastened to the anchor line, which are also carried along by the drop anchor. By means of this potting ground line, a curable potting compound, for example a concrete that hardens under water, is then injected under pressure into the firing channel Pressed, the anchor line at the same time serves to reinforce the Vergussmassesäule thus prepared in situ.

As a fall anchor according to the present invention, for example, a so-called torpedo pile is provided, which has a torpedo-shaped base body with a Eindringpitze and the end is provided with a plurality of torpedo wings for the purpose of stabilization.

The torpedo body may for example be hollow and comprise one or more ballast chambers that can be filled with a ballast.

The method has in particular the advantage over conventional pile foundations that a bracing of the structure to be paid to one or more anchor lugs can be done, which naturally leaves a certain amount of space in the placement of the offshore structure, so that the setting of the foundation piles not by a template or the underwater structure of the structure is given.

In addition, the setting of piles by means of piling devices is eliminated. The process of setting the torpedo / fall arrester is unique, whereas the ramming of stakes is accompanied by a recurring regularly frequent sound entry into the marine environment.

As a tension element in the context of the present invention, an anchor line or an anchor chain or an anchor cable is provided.

Of course, a plurality of tension elements / anchor cables, or anchor cables, or anchor chains can be attached to a fall anchor, although the following is a tension element in each case.

In any case, a tension element in the sense of the invention is a flexible tension element which can transmit only tensile forces, but not compressive forces.

In an advantageous variant of the method according to the invention it is provided that the potting compound is introduced over at least a partial length of the tension element in the firing channel, wherein the tension element remains in the cured potting compound. The tension element serves on the one hand the reinforcement of the potting compound, on the other hand, the bracing of the offshore structure to be built. Thus, the depth to be reached by the fall anchor depth is reduced because the required for bracing humor of the main structure of the tension element jacket friction is reduced and is supplied by the Vergussmassenkörper.

Conveniently, the tension member is provided at the side remote from the anchor anchor side with at least one float, which is arranged at a predetermined distance from the fall anchor, the distance chosen according to the planned depth of penetration of the drop anchor into the seabed and the height of the sea level above the seabed is such that the tension member and the potting grounding line connected thereto can float so that they can be captured by a supply ship.

The fall anchor is expediently provided with ballast before being dropped off, wherein the ballast mass is chosen such that the fall anchor penetrates into the seabed up to a load-bearing soil horizon.

In a particularly advantageous variant of the method, it is provided that the drop anchor is suspended from a discharge line and the dropping takes place by actuating a triggering mechanism on the discharge line. The fall anchor is struck in this case both on the discharge line as well as on one or more tension members.

In a favorable variant of the method according to the invention it can be provided that the fall anchor is introduced through a protective tube or a sheet pile wall into the seabed, wherein the protective tube or the sheet pile enclosure were previously set.

In order to facilitate penetration of the fall anchor into the seabed, provision may be made for the seabed to be fluidized beneath the protective tube or within the sheet pile enclosure prior to the fall anchor being removed by injection of compressed air or water.

Alternatively, it can be provided, for example, when using a protective tube, that the protective tube is pumped empty before dropping the drop anchor, so that the kinetic energy with which the drop anchor can penetrate into the seabed, significantly increased.

Alternatively, the protective tube, which may extend, for example, beyond the sea level, be pumped with a liquid, so that at the pipe base through the liquid column, an increased hydrostatic pressure is built up, which facilitates the penetration of the drop anchor into the seabed. The liquid column can be adjusted accordingly, for example, with regard to its specific weight. For example, can be used as a liquid barium spar solution application.

The protective tube can, for example, be flushed into the seabed to a certain depth before the drop anchor is dropped off.

The potting ground line can be provided, for example, with a plurality of outlet openings or outlet nozzles provided at a distance from one another in the longitudinal direction, so that the potting compound can penetrate uniformly over the height of the tension element into the firing channel.

It is also possible that the potting grounding line is pulled during potting. Then it is not absolutely necessary to provide several outlet openings for the potting compound. However, a pulling of the potting ground line can also be provided if a potting ground line with a plurality of distributed over the height and / or circumference arranged outlet openings for the potting compound application.

The potting grounding line can be lost at least over a subsection extending in the weft channel, i. remain in the firing channel via this section.

The object underlying the invention is further achieved by a foundation pile for offshore structures, comprising a drop anchor, at least one cast on this anchor line as a tension element and a cast in situ within the seabed and extending within the seabed over a length Vergussmassesäule, wherein the anchor tube extends over a partial length within the Vergussmassäule and at least to the sea level. The foundation pile according to the invention may comprise at least one protective casing which extends only over a partial length of the casting-mass column.

Alternatively, the foundation pile may be provided with a sheet piling enclosure extending over a partial length of the potting column.

The object underlying the invention is finally achieved by an offshore structure with a pile foundation, comprising a plurality of sinker sunk in the seabed and above the drop anchor extending, in-situ grouted Vergussmassesäulen, wherein the building is covered by anchor lugs, which are posted on the drop anchors.

Appropriately, the anchor lugs each extend through a Vergussmassäule or in this approximately longitudinally.

The offshore structure according to the invention may for example comprise a monopile, which has been constructed in a conventional manner and which comprises a bracing over a plurality of anchoring lugs.

The offshore structure according to the invention comprises a pile foundation formed according to the invention, the pile foundation being carried out by the method according to the invention.

The invention will be explained below with reference to an embodiment shown in the drawings.

Figur 1:

zeigt eine Seitenansicht eines Monopile-Fundaments eines Offshore-Bauwerks nach dem Stand der Technik,

Figur 2:

zeigt eine entsprechende Ansicht eines Offshore-Bauwerks, welches nach der Erfindung gegründet ist,

Figur 3:

zeigt eine Draufsicht der Ansicht gemäß Figur 2,

Figur 4:

zeigt eine Darstellung eines Torpedopiles gemäß der Erfindung,

Figuren 4a bis 4c:

zeigen den Torpedopile gemäß Figur 4 jeweils in der Oberansicht mit einem, vier oder fünf Ankertrossen und

Figuren 5, 5a, 5b:

das Absetzen des Torpedopiles nach dem erfindungsgemäßen Verfahren.

Show it:

FIG. 1:

shows a side view of a monopile foundation of an offshore structure according to the prior art,

FIG. 2:

shows a corresponding view of an offshore structure, which is founded according to the invention,

FIG. 3:

shows a plan view of the view according to FIG. 2 .

FIG. 4:

shows a representation of a Torpedopiles according to the invention,

FIGS. 4a to 4c:

show the torpedo line according to FIG. 4 each in the upper view with one, four or five anchor tubes and

FIGS. 5, 5a, 5b:

the settling of the torpedo pile according to the inventive method.

It is first referred to FIG. 1 showing a monopile 1 of the prior art. On the monopile 1, a transition piece 2 is mounted with a platform 3 and a connection structure, not shown. The transition piece 2 is referred to in the prior art as a so-called "transition piece".

The monopile 1 according to the invention has a relatively large diameter and was placed in the seabed 4 either by ramming or flushing.

The FIG. 2 shows in direct comparison to the FIG. 1 an offshore structure according to the invention also comprising a monopile 1, a transition piece 2 and a platform 3.

However, the monopile 1 according to the invention is shorter and slimmer than the monopile 1 according to the prior art. The former is guyed over four anchor lugs 5, each of which is posted to a foundation pile 6 in the seabed 4. More precisely, each anchor line 5 is fastened to a torpedo pile 7 and extends through a casting mass column 8 which is arranged above the torpedo pile 7 and which has been cast in situ in the seabed. The Vergussmassäule 8 has been created without permanent formwork and without standpipe, as will be explained below. Accordingly, the Vergussmassäule 8 has no regular outer contour.

The FIG. 3 shows a plan view of the arrangement according to FIG. 2 ,

An embodiment of the torpedo 7 is in FIG. 4 shown. The torpedo 7 is a drop anchor in the sense of the above. This comprises a torpedo-shaped base body 9, which has a Eindringpitze 10 at its leading end and its trailing end is provided with four guide vanes 11.

At the trailing in the direction of fall / rear end of the base body 9 an anchor tube 5 is struck, which is 12angeardnet concentric with a Vergussmasseleitung.

In the illustrated example, an extra concentric arrangement of Vergussmasseleitung and the anchor tube 5 is provided such that the anchor tube 5 extends within the Vergussmasseleitung 12, alternatively, of course, can be provided to move one or more Vergussmasseleitungen 12 parallel to the respective anchor line 5.

Of course, with a torpedo 7 more anchor lugs 5 may be connected, as in the Figures 4b and 4c is hinted at. These figures show each, as well as FIG. 4a , A plan view of the torpedo 7 according to FIG. 4 ,

In the method according to the invention, it is provided to shoot the torpedo parts 7 into the seabed 4 by utilizing a certain drop height and falling energy, wherein the torpedo pile 7 carries along the anchor line 5 and the casting ground line 12. Then, a potting compound, for example concrete, is pressed under pressure into the shot channel produced by the torpedo pile 7 in the subsoil 4, so that the in FIG. 2 above the torpedo 7 extending Vergussmassesäule 8 results. As potting compound is a concrete or anchor mortar into consideration. Hardens the potting compound, this results in the FIG. 2 illustrated foundation pile 6, from which the anchorage trunk 5 is led out. The settling of the torpedo 7 is in the Figures 5, 5a and 5b shown relatively simplified.

The torpedo pile 7 hangs on a crane 13, which is set up on a temporarily erected platform 3. The platform 3 may be part of the offshore structure to be anchored.

The torpedo pile 7 is struck on the one hand on the anchor pipe 5, on the other hand suspended from a discharge line 14.

It should be noted at this point that, of course, the torpedo pile 7 can be launched by a ship.

With a protective tube 15 is designated, whose diameter is slightly larger than that of the torpedo 7. The protective tube was only slightly washed into the subsoil 4 and extends well above sea level 16.

The torpedo pile 7 is inserted into the upper end of the protective tube 15, then the torpedo pile 7 is separated from the discharge strand 14 or with the Discharge strand 14, taking advantage of its kinetic energy dropped. The torpedo 7 falls through the protective tube 15 and penetrates into the seabed 4, where it is the simplest case only entrained in this anchored Ankertrosse 5 and the Vergussmasseleitung 12.

At the distal end of the anchor tube 5, a float 17 is attached, which allows floating of the anchor tube 5. The anchor pipe 5 can be picked up in this way by a supply ship and, for example, attached to the offshore structure and stretched.

The torpedo pile 7 may have been provided with appropriate ballast prior to discharge, which is why the base body 9 of the torpedo pile 7 may be provided with corresponding chambers.

The mass of a torpedo pile can amount to approximately between ten and one hundred tons, such a torpedo pile can for example have a length of up to twenty meters and a diameter of up to one meter.

LIST OF REFERENCE NUMBERS

1

monopile

2

Transition piece

3

platform

4

Subsoil

5

anchor lines

6

foundation pile

7

Torpedopile

8th

Vergussmassesäule

9

base body

10

indenting

11

vanes

12

Vergussmasseleitung

13

crane

14

shedding strand

15

thermowell

16

Sea level

17

float

Claims (18)

Method for producing a foundation pile for offshore structures, comprising the following method steps: Providing and arranging a drop anchor at a predetermined height above the seabed, Attaching at least one flexible tension element to the fall anchor, Attaching at least one potting grounding line to the tension element, - Throwing down the drop anchor so that it penetrates into the seabed, and - Introducing a curable potting compound in the shot channel generated by the fall anchor in the penetration into the seabed. A method according to claim 1, characterized in that the potting compound is introduced at least over a partial length of the tension element in the firing channel, wherein the tension element remains in the cured potting compound. Method according to one of claims 1 or 2, characterized in that the tension element is provided with at least one floating body, which is arranged at a predetermined distance from the fall anchor, the distance to the planned penetration depth of the drop anchor in the seabed and the height of the Sea level above the seabed is chosen. Method according to one of claims 1 to 3, characterized in that the drop anchor is provided with ballast prior to discarding, wherein the ballast mass is chosen so that the drop anchor penetrates to a viable soil horizon in the seabed. Method according to one of claims 1 to 4, characterized in that the drop anchor is suspended from a discharge line and the Discarding takes place by actuating a triggering mechanism on the discharge line. Method according to one of claims 1 to 5, characterized in that the drop anchor is brought through a protective tube or through a sheet pile enclosure in the seabed. A method according to claim 6, characterized in that the protective tube is flushed before dropping the drop anchor into the seabed. Method according to one of claims 6 or 7, characterized in that the seabed is fluidized within the protective tube or within the sheet pile enclosure prior to the dropping of the drop anchor by injection of compressed air or water. A method according to claim 6, characterized in that the protective tube is pumped empty before the drop anchor. Method according to one of claims 1 to 9, characterized in that at least one Vergussmasseleitung with a plurality of longitudinally spaced-apart outlet openings for the potting compound is applied. Method according to one of claims 1 to 10, characterized in that the Vergussmasseleitung is pulled during the casting. Method according to one of claims 1 to 11, characterized in that the Vergussmasseleitung is lost at least over the extending in the firing channel portion. A foundation pile (6) for offshore structures, comprising a fall anchor (7), at least one anchor line (5) attached thereto and an insulation layer cast in situ within the seabed (4) and located inside the structure Seabed (4) over a length of encapsulation pillar (8), the anchor duct (5) extending within the encapsulation column (8) and at least to the sea level (16). A foundation pile according to claim 13, having a protective casing which extends over a partial length of the grouting column (8). A foundation pile according to claim 13, comprising a sheet piling enclosure extending over a partial length of the potting mass column (8). Offshore structure with a pile foundation comprising a plurality of submerged in the seabed (4) torpedo parts (7) and above the torpedo piles (7) extending, in-situ grouted Vergussmasstäulen (8), the structure is anchored by anchor lugs (5), which on the Torpedo piles (7) are posted Offshore construction according to claim 16, characterized in that the anchor lugs (5) extend through the potting mass columns. Offshore structure according to one of claims 16 or 17, characterized in that it comprises a monopole (1) and a bracing over a plurality of anchoring lugs (5).

Images