Apparatus, system and method of extending piles into a seabed |
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申请号 | EP10180777.4 | 申请日 | 2010-09-28 | 公开(公告)号 | EP2309063A1 | 公开(公告)日 | 2011-04-13 |
申请人 | Aker Jacket Technology AS; | 发明人 | Alm, Torstein; | ||||
摘要 | A guiding apparatus (20), system and method for piles (12) to be extended into a seabed, comprising a plurality of pile guiding elements (24) interconnected by connection elements (19, 22), each guiding element (24) having respective guiding means (27) and respective support elements (32) for supporting the apparatus on the seabed (B). The guiding means (27) is supported by the support element (32) via articulation means (23), each articulation means (23) having a first end (21) connected to the guiding means (27) and a second end (30) connected to the support element and being individually adjustable, whereby the articulation means (23) of each guiding element (24) are operable to ensure that the guiding apparatus (20) may brought into a level state on an inclined or uneven seabed. | ||||||
权利要求 | |||||||
说明书全文 | The invention concerns installation of piles. More specifically, the invention concerns an apparatus and a system for installation of piles, a method of installing the apparatus and a method of installing piles into the ground. The invention is of particular use for subsea applications and for installing piles into the seabed in connection with the erection offshore wind-energy power plants. The state of the art includes various structures, such as slender circular columns, for supporting wind powered plants for generating electricity. When installed at sea, such plants are commonly supported by a lower truss structure, also referred to as a "jacket", fixed to the seabed via piles or similar devices known in the art. An example of a wind-powered plant for generating electricity is illustrated schematically in The jacket 4 supports a circular column or tower 2, for example via a load transferring element 10, and the tower carries a wind turbine 6 having at least one turbine blade 6a. The action of the wind, both directly and via the rotation of the turbine, generates considerable torsion in the tower, as well as bending moments in the transition between the tower and the jacket. It is therefore of great importance that the jacket is properly and sufficiently supported on the seabed, and consequently that the piles 12 are set with the required precision and verticality. It is known in the art to first install the piles in the seabed and the install the jacket on the pre-installed piles. Such pre-installation requires very high precision in order to for the jacket legs to fit precisely onto the piles. In order to ensuring that the piles are set in the correct position and inclination, it is known in the art to use various guide structures, operated either from a vessel or platform on the surface or via a subsea ROV. When the piles have been installed in the seabed, the structure (jacket) is placed on the piles, in a manner known in the art. As an example, piles used for this purpose may have a length of 45m, a diameter of 1.5m and a weight in air of approximately 60 tonnes. Typically, the piles are extended 40m into the seabed. Jackets for use in wind farms are often placed in comparatively shallow waters (e.g. 15 - 25m), and subsea operations give poor or non-existent visibility in the water. This makes the use of ROVs and divers difficult. It is therefore a need for a device and a method for ensuring accurate pre-installation of foundation piles, both in horizontal and vertical positions and orientations. It is also an object to provide an efficient and re-usable pile installation tool, whereby the installation time may be reduced. It is thus according to the invention provided a guiding apparatus for piles to be extended into a seabed, comprising a plurality of pile guiding elements interconnected by connection elements, each guiding element having respective guiding means and respective support elements for supporting the apparatus on the seabed, characterised in that the guiding means is supported by the support element via articulation means, each articulation means having a first end connected to the guiding means and a second end connected to the support element and being individually adjustable, whereby the articulation means of each guiding element are operable to ensure that the guiding apparatus may brought into a level state on an inclined or uneven seabed. The guiding means may comprise a tubular element having a first central axis and the support element may comprise a frusto-conical tubular element having a second central axis, and a portion of the guiding means is adjustably extendible inside the frusto-conical tubular element by said adjustment of the articulation means. Preferably, the articulation means are individually and selectively adjustable, whereby the guiding means and the frusto-conical tubular element are movable with respect to one another, both in an axial direction where the first and second central axes coincide and in an articulated manner where the first and second central axes do not coincide. The extent of articulation is substantially determined by the conical angle of the frusto-conical tubular element. In one embodiment, the articulation means are arranged with even spacing around the guiding element perimeter. In one embodiment, the articulation means comprise a hydraulic cylinder having a rod selectively adjustable between a retracted position and an extended position. Preferably, the articulation means of each guiding element are functionally interconnected, whereby each support element will adapt itself to the inclination of the seabed on which they are resting. In one embodiment, the invention comprises a rectangular pile installation frame having four pile guiding elements rigidly interconnected by connection elements. It is also according to the invention provided a system for installation of piles to be extended into a seabed, comprising a guiding apparatus having a plurality of pile guiding elements interconnected by connection elements, each guiding element having respective guiding means and respective support elements for supporting the apparatus on the seabed, said system also comprising control- and power means for connection to the guiding apparatus, characterised in that the guiding apparatus further comprises position-sensing means and inclination-sensing means operably connected via control means to the guiding elements, whereby the guiding apparatuses' horizontal and vertical positions may be adjusted and the guiding apparatus may brought into a level state on the seabed. Preferably, the guiding apparatus further comprises hydro-acoustic sensing means connected to a control unit, for sensing the movement and position of a pile being extended into the guiding element. In one embodiment, the guiding apparatus further comprises visual sensing means connected to a control unit, for sensing the movement and position of a pile being extended into the guiding element. Each guiding apparatus preferably comprises guiding means having a longitudinal opening for monitoring the position of the pile inside the guiding apparatus. The guiding apparatus preferably comprises a distance sensor for sensing the distance between a piling tool and an upper region of the guiding apparatus. It is also according to the invention provided a method of installing the guiding apparatus according to the invention, characterized by the steps of:
It is also according to the invention provided a method of extending a pile into a seabed by means of the system according to the invention, characterized by the steps of:
In one embodiment, the pile vertical position is measured using hydro-acoustic sensing means. In one embodiment, the pile vertical position is measured using visual sensing means. In one embodiment, the distance between a piling tool and an upper region of the guiding apparatus is measured simultaneously with step c). With the invention, a large number of piles may be pre-installed in a precise and efficient manner. These and other characteristics of the invention will be clear from the following description of a preferential embodiment, given as a non-restrictive example, with reference to the attached drawings wherein:
An embodiment of the guiding apparatus according to the invention is illustrated in In the illustrated embodiment, six actuators 23 (only four shown) connect the support element 32 to the guide funnel 27. The actuators 23 thus provide an adjustable, articulated connection between the guide funnel and the support element. The support element 32 comprises a foot plate, or mud mat, 26 for placement on the seabed, and a frusto-conical (i.e. truncated cone) element 28. Turning now to the sectional principle sketches in In Therefore, the actuators serve as an articulated joint between the support element and the guide funnel By selectively varying the stroke of the individual actuators 23 on the individual guiding element 24, the support element 32 and the guide funnel 27 may be adjusted such that the support element is resting against the somewhat inclined seabed, while the guide funnel 27 extends substantially vertically. By adjusting the actuators on all of the guiding elements 24 in this fashion, the pile installation frame 20 may be adjusted to a substantially level state on the seabed, its guide funnels 27 thereby having a vertical orientation. In a practical application, the guiding elements may accommodate a seabed inclination of 10° and the actuators may have maximum stroke of 1.5m. The actuators 23 may be hydraulic cylinders, interconnected via a subsea control unit 49 (see In one embodiment, the individual actuators 23 are selectively fluidly interconnected via fluid lines 52 and a remote control unit 49 (see The system for installing the pile installation frame 20 and for installing the piles, will now be described with reference to For use during the pile installation, cameras 42 and lights 42a, pan-and-tilt cameras 42', a sonar 38, and echo sounders 40 are also fitted to the guide frame. The sonar may be a digital multi-frequency scanning sonar, having a 360° operations range. A convenient camera configuration may be two cameras in each corner of the frame, for example having pan-and-tilt capabilities for 360° monitoring. The lights may preferably be of the LED type. The instrumentation platform also comprises a valve assembly, termed a Remote Control Unit (RCU) 49, the connection of which is schematically illustrated in An alternative embodiment of the instrumentation platform 34 is illustrated in With the system described above, an operator is able to:
Using the apparatus and system described above, the typical operation sequence is thus:
In In |