EP2558650B1 - Off shore foundation - Google Patents

Description

The invention relates to an anchoring element for a hydraulic system, in particular a mooring block or a gravity foundation for an offshore power generation plant or a centering and guiding aid for a monopile foundation and a hole in the body of water.

To form a permanent anchor point at the bottom of the water, a weight is typically sunk, from which a connecting chain is guided to an anchor buoy. This is exemplified in the US 2008/0112759 A1 directed. From this document go down to the bottom of the water lattice baskets that are filled with rocks. As an alternative, it is possible to form mooring blocks in the form of standardized concrete parts. A mooring block must have a high weight in order to serve as a safe anchor point. For the formation of anchoring elements for offshore installations, this leads to the need to use special installation vessels with a sufficient crane capacity to safely place heavyweight anchoring elements can.

To improve the durability of mooring blocks was by the JP 61046791 A the use of bottom-side, buried in the bottom of the body of water ground tips proposed on a mooring block. This approach requires a relatively soft sediment at the bottom of the water. A deposit of such a mooring block on rocky ground can lead to a reduced anchor effect. Therefore, to provide sufficient safety reserves usually the weight of such anchoring elements is increased, but this complicates the installation work.

A corresponding problem arises for gravity foundations of offshore energy generation plants. For the construction of wind turbines A marine location is exemplified by the DE 10 2005 006 988 A1 directed. Furthermore, appropriate, secured by the intrinsic gravity foundations for fully submersible tidal power plants known. In this case too, a rocky ground leads to particularly heavy foundation elements in order to be able to reliably exclude a displacement of the plant by wave and flow forces.

If a pile foundation (monopile) is used for plant foundation in a rocky body of water as an alternative to a gravity foundation, anchoring elements serve to center the hole to be made for the pile foundation and to secure the immediate footing of the foundation - this is on EP 1 988 219 A1 directed. Also for this application heavy anchoring elements are placed on the bottom of the water. Further disclosed GB 1 492 562 A a pile foundation for an oil platform, for which a foundation element is first deposited on the bottom of the water and then by the pressing of piles, which extend from the foundation element, is secured. The piles are extended by means of a back pressure by pumping seawater into a sealed receiving space for the piles. After extension, the receiving space is filled with sand.

The invention has for its object to provide an anchoring element for a hydraulic system, which relies on its own gravity on the body of water, the ballast weight used is low in relation to the load limiting loads, so that an installation with a simplified ship's vehicle is possible. The anchoring element should be particularly suitable for stony and rocky surfaces and are characterized by a long service life and by design and manufacturing simplicity.

The object underlying the invention is solved by the features of the independent claim. Advantageous embodiments emerge from the subclaims.

To improve on known anchoring elements that utilize a load weight for securing, the inventors have recognized that in side guides in Anchoring element movably arranged shear securing elements that wedge after weaning on the bottom of the water in the unevenness of the ground, significantly increase the capacity of the anchoring element against transverse forces. The shear securing elements used for this move only because of their own weight. Accordingly, the side guides transmit lateral forces, but leave each individual one of the thrust securing elements a degree of translational freedom, so that the thrust securing elements can extend without contact to the body of water without additional Aktorik.

Each of the thrust securing elements will occupy a certain equilibrium position when depositing the anchoring element on the bottom of the water. High loads on the anchoring element, in particular lateral forces, can lead to the movement of the entire anchoring element, without the individual contact points of the shear securing elements are significantly changed on the riverbed, i. the anchoring element clings as it were with the freely movable extendable Schubsicherungselementen in the relief of the substrate.

In the simplest case, the thrust securing elements are applied in a form-fitting manner to recesses in the body of the anchoring element, so that the walls of the recesses constitute the lateral guides for the thrust securing elements. For a preferred embodiment, the recesses are formed as passage openings in the anchoring element, so that the thrust securing elements can be inserted from above into the passage openings and a suitable fall-out, for example in the form of a flared expanded cross section in the head area include. When lowering the anchoring element, the thrust securing elements are then held by the fall-out and at the same time stand beyond the bottom region of the anchoring element. at Ground contact load the shear protection elements then with their own weight on the bottom of the water and drive so far until the entire anchoring element reaches its respective equilibrium position.

For an advantageous embodiment, the side guides are formed in the contact area to the thrust securing elements in the form of seawater-resistant plain bearings. For this purpose, the side guides themselves and / or passing with the side guides in contact parts of the thrust securing elements are covered with a suitable plain bearing material. For this purpose, in particular the known from the application for stern tubes material combinations in question. A particularly hard-soft pairing has proven to be particularly durable. That is, one of the contact surfaces is covered with a heavy duty polymer, such as Orkot®, while the mating surface is made of a hard material, such as stainless steel. Through such trained Schubsicherungselemente the essential part of the anchoring element and the thrust securing elements can be made of a concrete material. Fiber concrete is particularly suitable for reasons of strength. By the above-mentioned measure a direct, mutual sliding of the concrete components is avoided. Thus, the wall of the receptacles in the anchoring element can be covered with said plain bearing material, while the thrust securing elements are in the form of steel tubes, which are poured to increase the dead weight with concrete.

For an alternative design, the lateral guides for the thrust securing elements are provided in the form of spaced plates, for example of steel, with through openings through which thrust securing elements are guided. Particularly advantageously, the thrust securing elements are provided with different cross sections, which are adapted to the dimensioning of the passage openings, that the thrust securing elements are secured against falling out.

For a further alternative embodiment, the thrust securing elements are immediately adjacent to each other and have positive contact surfaces, which serve to realize the side guides and allow mutual sliding respectively adjacent thrust securing elements in the intended direction of free movement translation direction. For such a design, it is particularly conceivable to form the thrust securing elements as a matching dimensioned cuboid, which are surrounded by a frame-shaped element, which leads the thrust securing elements laterally against each other. The arrangement is supplemented by a fall protection.

The anchoring element according to the invention can stand for at least three thrust securing elements when depositing on a body of water for a first embodiment. The other elements are freely movable, that is they are not led to an end stop and thus do not take on the weight of the anchoring element. However, due to their intrinsic gravity, they press on an assigned contact point on the bottom of the river and, via the respective lateral guide, absorb the transverse forces acting on the anchoring element.

Alternatively, it is possible to support the anchoring element on another separate component. In the simplest case, this is the load-receiving frame of the anchoring element itself. For further development, the vertical loads are intercepted at support points on which lifting devices for leveling the anchoring element are provided. Such an embodiment can serve in particular for realizing a gravity foundation with an anchoring element according to the invention for establishing an offshore power generation plant. Accordingly, a centering and guiding aid for securing a hole in the riverbed or to create a monopile foundation can be realized by means of an anchoring element according to the invention.

Figuren 1a und 1b

zeigen als Querschnittansicht ein erfindungsgemäßes Verankerungselement vor und nach dem Absetzen auf dem Gewässergrund.

Figuren 2a und 2b

zeigen eine Ausgestaltungsvariante eines erfindungsgemäßen Verankerungselements in einer den Figuren 1a und 1b entsprechenden Darstellung.

Figuren 3a und 3b

zeigen ein weiteres, alternativ gestaltetes Verankerungselement im Querschnitt vor und nach dem Absetzen.

Figur 4

zeigt ein Schwerkraftfundament für eine Offshore-Energieerzeugungsanlage mit einem erfindungsgemäßen Verankerungselement in Teilschnittansicht.

Figur 5

zeigt eine Zentrier- und Führungshilfe für eine Monopile-Gründung mit einem erfindungsgemäßen Verankerungselement in Querschnittansicht.

In the following, the invention is explained in more detail by means of exemplary embodiments in connection with figure representations, in which the following details are shown:

FIGS. 1a and 1b

show a cross-sectional view of an inventive anchoring element before and after settling on the river bottom.

FIGS. 2a and 2b

show an embodiment variant of an anchoring element according to the invention in a FIGS. 1a and 1b corresponding representation.

FIGS. 3a and 3b

show another, alternatively designed anchoring element in cross-section before and after weaning.

FIG. 4

shows a gravity foundation for an offshore power plant with an anchoring element according to the invention in partial sectional view.

FIG. 5

shows a centering and guiding aid for a monopile foundation with an anchoring element according to the invention in cross-sectional view.

FIG. 1a shows in cross-sectional view an anchoring element 1 according to the invention, which comprises a cuboid concrete block 11 as a ballast weight 2. Shown is the lowering of a chain 10, which at the side Fastening 9.1, 9.2 is supported. An anchoring element designed in this way is preferably used as a mooring block.

In the concrete block 11, which is preferably designed to accommodate high loads made of fiber concrete, recesses 4.1 - 4.11 for receiving thrust securing elements 3.1 - 3.11 created. The recesses 4.1-4.11 are preferably arranged in the form of a matrix and, for the present embodiment, in the form of passage openings which extend from the top side 38 of the concrete block to the bottom area 39. In this case, the longitudinal axes of the recesses 4.1 - 4.11 are substantially vertical to the bottom surface 39 provided as a standing surface. Alternatively, a certain angle of attack is conceivable, which however is chosen to be steep and preferably <45 ° and particularly preferably <20 °, so that the thrust securing elements 3.1 - 3.11 overcome the frictional forces in the side guides and extend out of the recesses 4.1 - 4.11 due to their own weight in the intended for lowering orientation.

The thrust securing elements 3.1 - 3.11 are present in a cylindrical shape and run to a point. Furthermore, they have in the head area on a stop 7, which is applied in the form of a relation to the cross section of the recesses 4.1 - 4.11 oversized collar and forms a fall-out.

As side guides 5 for the thrust securing elements 3.1- 3.11 are respectively the walls of the recesses 4.1 - 4.11, which are positively applied to the lateral surface of the thrust securing elements 3.1 - 3.11.

In addition, the walls 12 are preferably covered with a plain bearing material 6. This is illustrated by way of example with reference to the recesses 4.1 for the thrust securing element 3.1. The plain bearing material 6 serves the frictional forces between the side guide 5 and the thrust securing element 3.1 - 3.11 to reduce so far that the weight of the thrust securing elements 3.1 - 3.11 sufficient to extend out of the recess 4.1 - 4.11. In addition, the abrasion on the thrust securing element 3.1 - 3.11 or on the walls 12 of the recesses 4.1 - 4.11 should be reduced in a constant movement of the anchoring element 1 under changing Aufömungsbedingungen or due to wave movements.

FIG. 1b shows the situation after the placement of the anchoring element 1 on the body of water 8. Here, the concrete block 11 rests at the support points 37.1, 37.2 on the bottom of the water 8. In general, at least three support points are present, which is not shown in the schematically simplified cross-sectional view.

For the present embodiment, the anchoring element 1 is not supported directly on the thrust securing elements 3.1 - 3.11. However, these are either in contact with the body of water 8 or are in a final position and are held by the fall-out. The latter case applies to the thrust securing element 3.6. The further thrust securing elements 3.1-3.5, 3.8-3.11 load with their own weight on the body of water 8 and assume an individual position as a function of the distance between the bottom area 29 of the concrete block 11 and the body of the water 8. So they follow the profile profile of the body of water 8 and engage in recesses so that the forces acting on the anchoring element 1 forces do not lead to a shift of the contact points. It is only possible that the concrete block 11 performs a pitching movement at high thrust forces, which leads to a certain movement of the thrust securing elements 3.1 - 3.11 along the associated side guides 5, without the contact of the thrust protection elements 3.1 - 3.11 lost at the body of water 8 itself.

The FIGS. 2a and 2b show a design alternative of the anchoring element 1 in cross-sectional view before and after settling on the body of water 8. The schematically illustrated thrust securing elements 3.1 - 3.7 are used to form the side guide 5 in through holes in a first guide plate 13 and a second guide plate 15, which are spaced parallel to each other, held. The first guide plate 13 and the second guide plate 15 are laterally cast in the concrete blocks 11.1, 11.2, which form the essential part of the weight 2. The arrangement is covered by a cover plate 20, which is formed in correspondence with the first guide plate 13 and the second guide plate 15 of a corrosion-resistant, sufficiently solid material. For example, these components can be applied as steel plates or as components made of fiber concrete.

For example, a lower through-opening 14 in the first guide plate 13 and an upper through-opening 16 aligned therewith in the second guide plate 15 are applied for the thrust securing element 3.1. As a result, the thrust securing element 3.1 is guided laterally at a steep angle, preferably <20 ° and particularly preferably substantially perpendicular to the setting direction. In this case, the narrower applied lower cylinder cross-section 17 of the thrust securing elements 3.1 - 3.11 engages through the lower passage opening 14. However, this is too narrow for the widened upper cylinder portion 18, whereby a fall-out 36 is realized. The upper cylinder portion 18 fits through the further applied, upper passage opening 16 and extends for the in FIG. 2a illustrated fully extended rest position of the thrust securing elements 3.1 - 3.11 on the second guide plate 15 addition. The projecting part forming a head 19 is rounded, so that when the thrust securing elements 3.1 - 3.11 are fully retracted, a gentle Sliding the head 19 is ensured on the inside of the overlying cover plate 20.

FIG. 2b shows the situation of the remote on the bottom of the river 8 anchoring element 1 FIG. 2a , It can be seen that the thrust securing elements 3.1 and 3.6 absorb the vertical loads of the anchoring element 1. Shown are the associated support points 37.1, 37.2. A necessary for the safe state third support point is not shown in the simplified cross-sectional view. The load-receiving thrust securing elements 3.1 and 3.6 are then in each case in the region of its head 19 on the inside of the cover plate 20 at. Lateral forces are introduced at the lower passage opening 14 in the first guide plate 13 and the upper passage opening 16 in the second guide plate 15. In the case shown, the additional thrust securing elements 3.2, 3.3, 3.5, 3.7 load with their own weight on the body of water 8 and convey on the respective side guides 5 in the case of a transverse movement of the anchoring element 1 restraining forces.

FIGS. 3a and 3b sketch a further embodiment of the invention. In this case, the concrete blocks 11.1, 11.2 and the cover plate 20 form part of an upwardly closed frame 40 for the accurately fitting thrust securing elements 3.1 - 3.6. These are designed so that each individual thrust securing element 3.1 - 3.6. a contact surface 21.1, 21.2, 21.3 to an adjacent element which allows a positive sliding in the direction provided for the extension direction, in this case the vertical. For the illustrated embodiment, the thrust securing elements 3.1 - 3.6 are selected as cuboid concrete blocks. These can be used for abrasion protection with a sliding bearing material, which is not shown in the figure sketch.

The individual, initially held by means of a fall-out protection 36 on the cover plate 20 Schubert shear securing elements 3.1 - 3.6 drive at ground contact after discontinuation of the anchoring element 1 on the body of water 8 depending on the present in place bumps. It is apparent that the thrust securing elements 3.1 and 3.5 are guided directly to the cover plate 20 and as a result supporting the anchoring element 1 supporting. The remaining thrust securing elements 3.2 - 3.4 and 3.6 are in an intermediate position, each burdening its own weight on the body of water 8 and the necessary relative position to the respective adjacent thrust securing elements 3.1 - 3.6 is effected by sliding along the contact surfaces 21.1 - 21.3. As a result, the topology of the base contact points of the thrust securing elements 3.1-3.6 adapted to the body of water 8 can be reliably trapped with the thrust forces on the anchoring element 1 via the lateral guide 5.

FIG. 4 shows a further development of the invention in the form of a gravity foundation 22 for an offshore power plant on which a wind turbine or, as shown here, a tidal turbine can be placed. Shown is a nacelle 27 with a water turbine rotating around it 28 and a subsequent tower adapter 26 which is placed on the coupling element 25 on the foundation-side support structure 24.

According to the invention, the gravity foundation 22 comprises an anchoring element 1 with slide securing elements 3.1-3.8 arranged vertically movably in recesses 4.1-4.8. These drive in the storage of the gravity foundation 22 on the body of water 8 while maintaining the ground contact and thus form the adapted bottom portion 39 of the gravity foundation 22nd

The gravity foundation is leveled by the lifting devices 23.1 and 23.3, which support the weight force of the gravity foundation 22. Accordingly, the vertically freely movable thrust securing elements 3.1 - 3.8 capture a substantial portion of the lateral forces acting on the gravity foundation 22 during operation of the system.

For a further design alternative, the stability of the gravity foundation 22 can be increased by supplying a cement mixture to a further production step via a feed channel 35 for filling cavities. For this embodiment, the thrust securing 3.1 - 3.8 serve the initial stability during installation until the cement paste is finally cured.

FIG. 5 shows a centering and guide aid 30 for a hole, such as to form a monopile foundation. Shown again is a foundation element, with a concrete block 11, which serves as a ballast weight 2 and at the same time as a support component. According to the invention arranged on the concrete block 11 thrust securing elements 3.1 - 3.8 are applied by means of their own weight in the recesses 4.1-4.8 vertically freely movable. These in turn serve to adapt to the course of the body of water 8. After leveling by the lifting devices 23.1, 23.2 can be lowered by the guide tube 31, a drill pipe 32 centered with the drill head 33 in a borehole 34.

Further embodiments of the invention will become apparent from the following claims. It is particularly conceivable, the side guides 5 for the thrust securing elements 3.1 - 3.11 create so that they extend in an angular position to the setting direction. Furthermore, it is possible to divide the thrust securing elements 3.1 - 3.11 into different groups, the differ by their extension direction and by their weight or their extension length or with respect to the design of the contact area to the river bottom. Furthermore, the entire outer surface of the anchoring element 1 can be covered with thrust securing elements 3.1 - 3.11, wherein only a part of the thrust securing elements 3.1 - 3.11 comes into contact with the body of water 8 as a function of the depositing direction. As a result, the anchoring element 1 can be placed independently of the direction of the body of water 8, which simplifies the installation.

LIST OF REFERENCE NUMBERS

1

anchoring element

2

ballast weight

3.1 - 3.11

Thrust protection element

4.1-4.11

recess

5

cornering

6

plain bearing material

7

attack

8th

body of water

9.1, 9.2

fastener

10

Chain

11, 11.1, 11.2

concrete block

12

wall

13

first guide plate

14

lower passage opening

15

second guide plate

16

upper passage opening

17

lower cylinder section

18

upper cylinder section

19

head

20

cover plate

21.1, 21.2, 22.3

contact surface

22

Gravity Foundation

23.1, 23.2

hoist

24

support structure

25

coupling element

26

tower adapter

27

nacelle

28

water turbine

29

Offshore power generation plant

30

Centering and guide assistance

31

guide tube

32

drill pipe

33

wellhead

34

well

35

feed

36.1 - 36.6

Drop-out safety

37.1, 37.2

support point

38

top

39

floor area

40

frame

Claims (8)

1. An anchoring element (1) for a hydraulic engineering installation having at least one ballast weight (2) for weighting purposes; characterized in that the anchoring element (1) comprises a plurality of shear-protection elements (3.1-3.11) which are arranged movably on lateral guides (5) in the anchoring element (1) such that, when the anchoring element is deposited on the bottom of a body of water (8), the shear-protection elements (3.1-3.11) bear down on the bottom of the body of water (8) under their own weight when in contact with said bottom and move individually along the respective lateral guide (5) until the anchoring element (1) assumes a position of equilibrium.
2. The anchoring element according to claim 1, characterized in that each of the shear-protection elements (3.1-3.11) is arranged inside a recess (4.1-4.11) in the anchoring element (1) and the walls (12) of the recesses (4.1-4.11) form the lateral guides (5).
3. The anchoring element according to one of claims 1 or 2, characterized in that the lateral guides (5) and/or parts of the shear-protection elements (3.1-3.11) coming into contact with the lateral guides (5) are covered with a friction bearing material (6).
4. The anchoring element according to one of claims 1 to 3, characterized in that at least one part of the shear-protection elements (3.1-3.11) is in direct lateral contact to one another, where the individual shear-protection elements (3.1-3.11) can slide on one another and the lateral guide (5) is effected by the alternate contact surfaces of adjoining shear-protection elements (3.1-3.11) adjacent to one another.
5. The anchoring element according to one of the preceding claims, characterized in that the shear-protection elements (3.1-3.11) are secured against falling out from the anchoring element (1).
6. The anchoring element according to one of the preceding claims, characterized in that the anchoring element (1) is at least partially fabricated from fibre reinforced concrete.
7. The anchoring element according to one of the preceding claims, characterized in that the anchoring element (1) comprises a lifting device (23.1, 23.2) for levelling after placement on the bottom of the body of water (8).
8. A hydraulic engineering installation having an anchoring element according to one of the preceding claims, wherein the hydraulic engineering installation serves as a gravity foundation (22) for an offshore power generating plant (29) or as a mooring block or as a centering and guidance aid (30) for erecting a monopile foundation or for a drilling on the bottom of a body of water (8).

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