PILE DRIVING METHODS AND SYSTEMS FOR DRIVING A PILE

Abstract

A pile driving method for driving a pile, e.g. a hollow and open ended pile, e.g. a large diameter pile having an outer diameter of at least 5 meters, e.g. a monopile of an offshore wind turbine, into the soil, e.g. into the seabed. Use is made of a pile driving system which comprises a drive head member that is configured to engage the pile, and a solid mass drop weight assembly comprising a support structure and comprising solid drop weight elements supported by said support structure, preferably solid steel drop weight elements being composed of steel elements, e.g. stackable steel elements, which drop weight elements have a total mass of at least 100 tonnes, e.g. more than 500 tonnes, e.g. more than 1000 tonnes, e.g. more than 2000 tonnes, which drop weight assembly is vertically mobile relative to, e.g. above, the drive head member. Further use is made of a lift system that is configured to bring the drop weight assembly into an initial height position relative to the drive head, and a quick release system adapted to effect quick release

Claims

1. A pile driving method for driving a large diameter pile having an outer diameter of at least 5 meter into -the seabed, wherein use is made of a pile driving system comprising: a drive head member arranged on a top end of the pile; a solid mass drop weight assembly comprising a support structure and comprising solid drop weight elements supported by said support structure the drop weight elements having a total mass of more than 500 tonnes, the drop weight assembly being vertically mobile above the drive head member; a lift system arranged between the drive head member and the drop weight assembly is the lift system being configured to bring the drop weight assembly into an initial height position relative to the drive head member; a quick release system adapted to effect quick release of the lift system, so that the drop weight assembly falls down from said initial height position; and an energy transfer assembly configured for transfer of energy from the falling drop weight assembly to the drive head member; wherein, for driving the pile into the seabed the drop weight elements are loaded onto the support structure to set a desired total mass of the drop weight assembly; the method comprising a repeated cycle comprising the steps of: lifting the drop weight assembly with the lift system into a desired initial height position; operating the quick release mechanism to effect quick release of the lift system, so that the drop weight assembly falls down from said initial height position towards the drive head member; and transferring energy from the falling drop weight assembly by said energy transfer assembly to the drive head member and thereby to the top end of the pile, so that the pile is driven deeper into the seabed.

2. A pile driving method for driving a large diameter pile having an outer diameter of at least 5 meters into the seabed, wherein use is made of a pile driving comprising: a drive head member arranged on a top end of the pile; a liquid filled drop tank is filled with more than 500 m3 of a liquid therein and vertically mobile above the drive head member; a lift system arranged between the drive head member and the liquid filled drop tank, is the lift system being configured to bring the liquid filled drop tank into an initial height position relative to the drive head; a quick release system adapted to effect quick release of the lift system, so that the liquid filled drop tank falls down from said initial height position, and an energy transfer assembly configured for transfer of energy from the falling liquid filled drop tank to the drive head member, wherein, for driving the pile into the seabed the liquid filled drop tank is at least partially filled with said liquid to set a desired total mass of the liquid filled drop tank, the method comprising a repeated cycle, comprising the steps of: lifting the liquid filled drop tank with the lift system into a desired initial height position; operating the quick release mechanism to effect quick release of the lift system, so that the liquid filled drop tank falls down from said initial height position towards the drive head member; and transferring energy from the falling liquid filled drop tank by said energy transfer assembly to the drive head member and thereby to the top end of the pile, so that the pile is driven deeper into the seabed.

3. The pile driving method according to claim 1, wherein said energy transfer is devoid of mechanical impact energy transfer between the drop weight assembly and drive head or between the drop tank and drive head.

4. The pile driving method according to claim 1, wherein said energy transfer assembly comprises one or more spring devices and/or one or more damper devices, that are effective between the drop weight assembly and the drive head member or between the drop tank and the drive head member.

5. The pile driving method according to claim 1, wherein the pile has an open foot end and an outer diameter of at least 5 meter.

6. The pile driving method according to claim 1, wherein the energy transfer assembly comprises multiple gas spring devices comprising a compressible gas filled variable volume chamber that is reduced in volume as the drop weight assembly or the drop tank falls.

7. The pile driving method according to claim 1, wherein the energy transfer assembly comprises multiple liquid damper devices, each comprising a liquid filled variable volume chamber and an associated liquid flow resistance through which at least a part of said liquid is forced upon compression of the liquid filled variable volume chamber as the drop weight assembly or the drop tank falls.

8. The pile driving method according to claim 1, wherein the energy transfer assembly comprises multiple energy transfer devices, said multiple energy transfer devices being arranged in a circular array on the drive head member or on the drop weight assembly or on the liquid filled drop tank.

9. The pile driving method according to claim 1, wherein the energy transfer assembly comprises multiple integrated spring and damper devices, wherein each integrated spring and damper device comprises a compressible gas filled variable volume chamber that is reduced in volume as the drop weight assembly or drop tank falls, and wherein each integrated spring and damper device comprises a liquid filled variable volume chamber and an associated liquid flow resistance through which at least a part of said liquid is forced upon compression of the liquid filled variable volume chamber as the drop weight assembly or drop tank falls.

10. The pile driving method according to claim 1, wherein the pile driving system comprises a vertical guide structure configured to vertically guide the drop weight assembly or drop tank relative to the drive head member.

11. The pile driving method according to claim 6, wherein the one or more spring devices and/or the one or more damper devices are arranged on the drive head member, each engaging at a lower end thereof the drive head member.

12. The pile driving method according to claim 1, wherein an array of multiple spring devices and/or of multiple damper devices is arranged underneath the support structure.

13. The pile driving method according to claim 1, wherein the lift system comprises multiple hydraulic lift cylinders, and wherein the quick release system comprises one or more quick release valves that are opened to allow rapid discharge of hydraulic liquid from the lift cylinders.

14. The pile driving method according to claim 1, wherein the lift system comprises multiple hydraulic lift cylinders, and wherein the hydraulic liquid of the multiple lift cylinders is circulated through a heat exchanger system so as to cool the hydraulic liquid, said heat exchanger system being fed with seawater for cooling the circulated hydraulic liquid.

15. The pile driving method according to claim 1, wherein the energy transfer assembly comprises multiple liquid damper devices, each comprising a liquid filled variable volume chamber and an associated liquid flow resistance through which at least a part of said liquid is forced upon compression of the liquid filled variable volume chamber as the drop weight assembly or the drop tank falls, and wherein the liquid of the multiple liquid damper devices is circulated through a heat exchanger system so as to cool said liquid, the heat exchanger system being fed with seawater for cooling the circulated damper liquid.

16. The pile driving method according to claim 1, wherein the drive head member is provided with vertical guide members, and wherein the drop weight is composed of stackable steel elements stacked on the support structure between the vertical guide members.

17. (canceled)

18. The pile driving method according to claim 1, wherein said energy transfer assembly comprises one or more spring devices and/or one or more damper devices, that are effective between the drop weight assembly or the drop tank and the drive head member, and wherein said one or more spring devices and/or one or more damper devices are cooled by seawater being circulated through or along external wall portions of the one or more spring devices and/or one or more damper devices and/or by cooling seawater being sprayed on external wall portions of the one or more spring devices and/or one or more damper devices.

19-38. (canceled)

39. The pile driving method according to claim 1, wherein the desired total mass is set to at least 1000 tonnes.

40. The pile driving method according to claim 1, wherein the pile is a monopile of an offshore wind turbine.

41. The pile driving method according to claim 2, wherein the liquid that has been filled into the drop tank is seawater.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0120] In the drawing:

[0121] FIG. 1 shows schematically and not to scale, an example a pile driving system according to the first aspect of the invention in a pile driving method for driving a pile, e.g. a hollow and open ended pile,

[0122] FIG. 2 shows the system of FIG. 1 after the solid mass drop weight assembly has been allowed to fall from the initial position thereof,

[0123] FIG. 3 shows a jack-up marine vessel provided with a crane and pile driving system according to the invention, as well as a monopile to be driven into the seabed,

[0124] FIG. 4 shows in cross-section, schematically, a pile driving system according to the according to the first aspect of the invention, wherein the exchangeable drive head member adapter part is configured to engage a relatively smaller diameter pile,

[0125] FIG. 5 shows the pile driving system of FIG. 4, wherein the exchangeable drive head member adapter part is configured to engage a relatively larger diameter pile,

[0126] FIG. 6 shows cross-section A-A of the embodiments of FIGS. 4 and 5,

[0127] FIG. 7 shows a view from above onto the pile driving system of FIG. 4,

[0128] FIG. 8 illustrates the pile driving system of FIG. 4 placed on deck of the vessel,

[0129] FIGS. 9a-f illustrate driving a pile using the pile driving system of FIG. 4,

[0130] FIG. 10 shows the vessel of FIG. 3 with pile holder holding the pile 1 ahead of pile driving using the pile driving system of FIG. 4,

[0131] FIG. 11 shows the vessel of FIG. 10 with the pile driving system placed on the pile using the crane,

[0132] FIGS. 12a, b show the pile driving system of FIG. 4 during various stages of operation,

[0133] FIGS. 12c, d, e illustrates the lifting tool approaching, engaging and connecting to the uppermost set of drop weight elements,

[0134] FIG. 13 shows the vessel with the pile driving system of FIG. 4 placed on top of the pile held vertically by the pile holder of the vessel,

[0135] FIG. 14 illustrates the crane being operated while the set of drop weight elements is being lowered to the functional position thereof using the lifting tool,

[0136] FIG. 15 illustrates placing a set of drop weight elements on the support structure of the drop weight assembly using the lifting tool and a crane,

[0137] FIG. 16. shows schematically and not to scale, an example a pile driving system according to the second aspect of the invention in a pile driving method for driving a pile, e.g. a hollow and open ended pile,

[0138] FIG. 17 shows an alternative pile driving system according to the invention in a pile driving method for driving a pile, e.g. a hollow and open ended pile.

DETAILED DESCRIPTION OF EMBODIMENTS

[0139] In FIG. 1 it is schematically shown that a pile, e.g. a hollow and open ended pile, e.g. a large diameter hollow and open ended pile 1, of which only a top is shown, having an outer diameter of at least 5 meters, e.g. a monopile of a wind turbine, is driven into the soil, e.g. into the seabed by means of a pile driving system 7 according to the invention.

[0140] In FIG. 1 the drop weight assembly 10 of the pile driving system 7 is in the initial height position thereof relative to the drive head member 8. In FIG. 2 that drop weight assembly 10 is at the end of the vertical fall, after the quick release mechanism 25 has been operated and the assembly 10 has fallen due to gravity.

[0141] The pile driving system 7 comprises:

[0142] a drive head member 8 that is configured to engage the pile, e.g. is configured to be arranged on the top end of the pile 1,

[0143] a drop weight assembly 10 that is vertically mobile relative to, here above, the drive head member 8,

[0144] a lift system 20 arranged between the drive head member 8 and the drop weight assembly 10, that is configured to bring the drop weight assembly 10 into an initial height position relative to the drive head member 8,

[0145] a quick release system 25 that is adapted to effect quick release of the lift system so that the drop weight assembly falls down from said initial height position,

[0146] an energy transfer assembly 30 configured for transfer of energy from the falling drop weight assembly 10 to the drive head member 8.

[0147] The drive head member 8 may have a mass of at least 100 tonnes, e.g. at least 250 tonnes, e.g. of more than 500 tonnes.

[0148] The solid mass drop weight assembly comprises a support structure 11 and comprises multiple solid drop weight elements 12a-d that are supported by the support structure 11.

[0149] The support structure 11 may be construed with a platform on which the weight elements 12a-d are stacked.

[0150] The support structure 11 or the drive head member 8 may be provided with vertical guide members 13, here pylons, thereon.

[0151] The vertical guide members 13 may be configured and used as guides during stacking and destacking of solid drop weight elements 12a-d. For example, the guide members 13 are configured to interact with a lifting tool 6 of a crane 4 that is used in said stacking and destacking of the elements 12, so that the tool is guided by said guide members.

[0152] In a practical embodiment, the drop weight is composed of stackable steel elements, e.g. planar steel elements, that are stacked on the support structure between the pylons.

[0153] For example, four pylons 13 are arranged in a rectangular grid on the support structure 11 or on the drive head member 8. For example, elongated steel plates are stacked between the four pylons.

[0154] For example, as shown in FIG. 7, each solid steel drop weight elements 12a-d may have one or more slide pad members 12g configured for sliding engagement with a vertical guide member, e.g. pylon 13.

[0155] As preferred, the elements 12a-d are solid steel drop weight elements being composed of steel elements, here stackable steel elements. During pile driving the drop weight elements have a total mass of at least 100 tonnes, e.g. more than 500 tonnes, e.g. more than 1000 tonnes, e.g. more than 2000 tonnes.

[0156] As explained herein, for driving the pile 1 into the soil, the drop weight assembly 10 is arranged to have a desired mass, which is here achieved by stacking a desired number of steel elements 12a-d on the support structure 11.

[0157] The method comprising a repeated cycle wherein: [0158] the drop weight assembly 10 is lifted by means of the lift system 20 into a desired initial height position, [0159] the quick release mechanism 25 is operated to effect quick release of the lift system so that the drop weight assembly 10 falls down from said initial height position towards the drive head member due to gravity.

[0160] Herein energy from the drop weight assembly 10 is transferred by the energy transfer assembly 30 to the drive head member 8 and thereby to the pile 1, here to the top end of the pile, so that the pile 1 is driven deeper into the soil. This cycle is repeated till the desired penetration depth is reached.

[0161] As explained it is envisaged that the energy transfer from the drop weight assembly 10 to the pile drive head member 8 is devoid of mechanical impact energy transfer between the drop weight assembly 10 and drive head member 8. As shown here the energy transfer assembly is devoid of an anvil.

[0162] The energy transfer assembly 30 comprises one or more spring devices and/or one or more damper devices, e.g. embodied like the mentioned oleo-pneumatic integrated spring and damper devices. These devices are here mounted on the drive head member 8 in a circular or other shaped array and are effective between the drop weight assembly and the drive head member.

[0163] The pile 1 here has an open foot end and an outer diameter of at least 5 meter, e.g. of between 5 and 12 meters. Preferably, the pile 1 is hollow over its length.

[0164] For example, the pile 1 has a length of 80 meters or more, e.g. over 100 meters.

[0165] For example, the pile 1 has a mass of 800 tonnes or more, e.g. over 1000 tonnes. As explained herein, the total mass of the drop weight assembly can be of similar magnitude or even greater.

[0166] In embodiments, the energy transfer assembly 30 comprises multiple gas spring devices, e.g. telescopic devices, each comprising a compressible gas filled variable volume chamber that is compressed with resultant increase of gas pressure upon compression of the liquid filled variable volume chamber by the falling drop weight assembly.

[0167] In embodiments, the energy transfer assembly 30 comprises multiple liquid damper devices, e.g. telescopic devices, each comprising a liquid filled variable volume chamber and an associated liquid flow resistance through which at least a part of said liquid is forced upon compression of the liquid filled variable volume chamber by the falling drop weight assembly.

[0168] It is illustrated here that the energy transfer assembly 30 comprises multiple integrated spring and damper devices 31, these multiple integrated spring and damper devices 31 being arranged in a circular array on the drive head member 8. These devices are vertically telescopic to form one or more chambers for gas and for damping liquid.

[0169] Instead of, or in combination with, damping using liquid damping other damping devices can be applied, e.g. based on mechanical friction.

[0170] As explained, each integrated spring and damper device 31 may comprise a compressible gas filled variable volume chamber that is reduced in volume by the falling drop weight assembly and each integrated spring and damper device comprises a liquid filled variable volume chamber and an associated liquid flow resistance through which at least a part of said liquid is forced upon compression of the liquid filled variable volume chamber by the falling drop weight assembly.

[0171] The energy transfer assembly 30 may comprise one or more pressurized gas storage vessels 35, that are in communication with the compressible gas filled variable volume chambers.

[0172] In embodiments, a vertical guide structure is provided that is configured to vertically guide the drop weight assembly 10 relative to the drive head member 8. For example, a telescoping guide member is provided. For example, the telescoping guide member comprises an annular guide member surrounding the drive head member and having a section protruding above the drive head.

[0173] It is illustrated that the one or more spring devices and/or one or more damper devices, e.g. embodied as integrated spring and damper devices 31, are arranged on the drive head member 4, each device 31 engaging at a lower end thereof the drive head member 8 and each engaging at an upper end thereof the structure 11, e.g. being connected thereto.

[0174] It is illustrated here that an array of multiple spring devices and of multiple damper devices, e.g. embodied as multiple integrated spring and damper devices 31, is arranged.

[0175] As preferred, the lift system 20 comprises multiple hydraulic lift cylinders 21 and an associated hydraulic pump 22. The quick release system 25 comprises one or more quick release valves 26 that are opened to allow rapid discharge of hydraulic liquid from the lift cylinders. As preferred, the hydraulic liquid of the one or more lift cylinders 21 is circulated through a heat exchanger system so as to cool the hydraulic liquid, e.g. said heat exchanger being fed with seawater for cooling the circulated hydraulic liquid in case the pile is installed into the seabed.

[0176] As preferred, the liquid of the multiple liquid damper devices 31 is circulated through a heat exchanger system so as to cool said liquid, e.g. a volume of liquid in the circulation circuit being at least 10 times greater than the volume of the liquid filled variable volume chambers of the multiple liquid damper devices, e.g. the heat exchanger being fed with seawater for cooling the circulated damper liquid in case the pile is installed into the seabed.

[0177] In FIG. 3 a marine vessel 2, here a jack-up marine vessel, with a deck 3 and a crane 4 is shown. The crane 4 comprises a hoist assembly 5 and is revolvable about a vertical axis. The crane 4 has a boom which is pivotable over a horizontal axis by employing a luffing mechanism. An embodiment of the pile driving system 7 according to the invention is also shown above a pile 1 to be driven into the soil.

[0178] Solid drop weight elements 12s, and 12a-c of this pile driving system 7 are stored in a storage position thereof on the deck 3.

[0179] This pile 1 is e.g. a hollow and open ended pile, e.g. a large diameter hollow and open ended pile 1 having an outer diameter of at least 5 meters, e.g. a monopile of a wind turbine, is driven into the soil, e.g. into the seabed by means of a pile driving system 3 according to the invention.

[0180] The marine vessel 2 further comprises a lifting tool 6 configured to engage, retain and release both a set of solid drop weight elements 12s and 12a-c, and the pile driving system 7.

[0181] The tool 6 is configured to be suspended from the hoist assembly 5, so that the crane 4 is able to move the pile driving system 7 between a storage position thereof, e.g. on the deck 3 of the vessel 2, and a pile driving position thereof in which it is arranged on the top end of the pile 1 such as to engage said top end, and to move a set of solid drop weight elements 12s, 12a-c between the drop weight assembly 10 between a storage position thereof, e.g. on the deck 3 of the vessel 2 as shown, and a functional position thereof in which the set of solid drop weight elements is stacked onto the support structure 11 of the pile driving system 7.

[0182] As preferred, the tool 6 has one or more, here four in a cross arrangement, positioning arms 6b that are configured to be brought into contact with a respective vertical guide member or pylon 13. This allows to orient the tool 6 relative to the drop weight elements, e.g. to allow one or more mobile pins 6a to engage in respective holes in connectors 11n.

[0183] FIGS. 4 and 5 illustrate a vertical cross-section of embodiments of the pile driving system 7.

[0184] The drive head member 8 is arranged on and engages the top end of the pile 1. As explained the drive head member 8 comprises an exchangeable pile top adapter part with a cylindrical sleeve portion 8a that is configured to be placed about the top end of the pile and an inward top flange 8b that is configured to be rested on a flange at the top end of the pile. The exchangeable pile top adapter part further comprises a section extending above the inward top flange 8b.

[0185] In the FIGS. 4, 5, the same features as discussed for the schematic FIGS. 1 and 2 may be recognized.

[0186] FIG. 6 shows the cross-section A-A of the embodiments of FIGS. 4 and 5, the location of the cross-section A-A being indicated in FIG. 5.

[0187] It is illustrated that the pile driving system 7 comprises:

[0188] the drive head member 8 that is configured to be arranged on the top end of the pile 1 such as to engage the pile,

[0189] a drop weight assembly 10 that is vertically mobile relative to, here above, the drive head member 8,

[0190] a lift system 20, arranged between the drive head member 4 and the drop weight assembly 10, that is configured to bring the drop weight assembly into an initial height position relative to the drive head member 8,

[0191] a quick release system 25 that is adapted to effect quick release of the lift system so that the drop weight assembly falls down from said initial height position,

[0192] an energy transfer assembly 30 configured for transfer of energy from the falling drop weight assembly 10 to the drive head member 8.

[0193] The drive head member 8 comprises an exchangeable adapter part 9, which in the embodiment of FIG. 4 is configured to engage a relatively small diameter pile 1, here in the on scale figure of about 6 meters diameter, and which in the embodiment of FIG. 5 configured to engage a relatively larger diameter pile, here in the on scale figure of about 9 meters diameter.

[0194] In FIG. 4, the pile driving system 7 is shown while the drop weight assembly 10 of the pile driving system 7 is in the initial height position thereof relative to the drive head member 8. In FIG. 5 the drop weight assembly 10 is at the end of the vertical fall, after the quick release mechanism has been operated and the assembly 10 has fallen due to gravity only, so absent any acceleration mechanism.

[0195] The solid mass drop weight assembly 10 comprises a support structure 11 and comprises multiple solid drop weight elements 12s, 12a-c that are supported by the support structure 11.

[0196] The support structure 11 is construed with a platform on which the weight elements 12s, 12a-d are stacked.

[0197] The support structure 11 or the drive head member 8 is provided with vertical guide members 13, here pylons, thereon, configured and used as guides during stacking and destacking of solid drop weight elements 12s, 12a-c. The drop weight is composed of stackable planar steel elements 12s, 12a-c that are stacked on the support structure between the pylons.

[0198] As shown here, the multiple pylons 13 can be arranged within the circular array of energy transfer devices 31, which allows to keep the diameter of the system limited.

[0199] As best visible from FIG. 6, four pylons 13 are arranged in a rectangular grid on the drive head member 3, here on the upper portion thereof.

[0200] The multiple solid drop weight elements are arranged in sets of four solid drop weight elements with a special configuration. In FIGS. 4 and 5, five sets of solid drop weight elements are stacked on the support structure 11. As indicated in FIG. 4, each set comprises a rectangular base drop weight element 12s, which comprises multiple vertically protruding parts with each a connector 12n, and three rectangular additional drop weight elements 12a, 12b and 12c. The additional drop weight elements 12a-c comprise openings 12o which match with the protruding parts, so that they can be placed on top of the base drop weight element 12s of a respective set. On top of the uppermost additional drop weight element 12c of a first set indicated in FIG. 4, a further, second set of drop weight elements is stacked, but then turned 90° over a vertical axis with respect to the first set. The rest of the stack is built up in the same way. The connectors 12n of each base drop weight element 12s are connectable to the lifting tool 6.

[0201] In FIG. 5, it is shown that the lifting tool 6 engages the connectors 12n of the base drop weight element 12s of the uppermost set of drop weight elements, so as to place the set on the set below it, or to remove it from the mass drop weight assembly 10. The lifting tool is shown in a top view in FIG. 7.

[0202] As explained, for driving the pile 1 into the soil, the drop weight assembly 10 is arranged to have a desired mass, which is here achieved by stacking a desired number of steel elements 12s, 12a-c on the support structure 11. This is illustrated in FIGS. 9a-9f, which consecutively show a progression of increasing mass of the drop weight assembly 10 as more sets of solid drop weight elements 12s, 12a-c are stacked on the support structure 11.

[0203] The energy transfer assembly 30 of the pile driving system 7 comprises multiple integrated spring and damper devices 31, these multiple integrated spring and damper devices 31 being arranged in a circular array on the drive head member 8. These devices are vertically telescopic to form one or more chambers for gas and for damping liquid.

[0204] As explained, each integrated spring and damper device 31 may comprise a compressible gas filled variable volume chamber that is reduced in volume by the falling drop weight assembly and each integrated spring and damper device comprises a liquid filled variable volume chamber and an associated liquid flow resistance through which at least a part of said liquid is forced upon compression of the liquid filled variable volume chamber by the falling drop weight assembly.

[0205] As shown in FIG. 8, the adapter part 9 and pylons 13 are attuned to each other such that the drive head member 4 may be placed onto a stack of drop weight elements 12s and 12a-c, which is on top of the deck 41. The drop weight elements are stacked on the deck on top of each other in the same way in between similar pylons as they are to be stacked in between the pylons 13 of the pile driving system 2. The center of gravity c.sub.g of the stack and pile driving system 2 together in this storage configuration, is shown in FIG. 8 as well.

[0206] Similar to the base drop weight elements 12s comprising the connector 12n, the support structure 11 also comprises protruding parts with each a connector 11n, which are connectable to the lifting tool 6. This is indicated in FIGS. 5 and 8.

[0207] The tool 6 here comprises movable pins 6a that are selectively movable into and out of a hole made in connector 11n.

[0208] In a possible method for pile driving, in which the pile driving system 7 is stored in a storage position thereof on the vessel, e.g. on the deck 3, e.g. in the manner shown in FIG. 8, comprises the step of connecting the pile driving system 3 to the lifting tool 6 of the vessel 2 so that the pile driving system 7 can be moved to the pile driving position thereof on the pile 1. This connecting step is illustrated in FIG. 10—therein the pile 1 is being held in place laterally by a pile gripper 40.

[0209] The method comprises the step of employing the crane 4 to move the pile driving system 7 from the storage position thereof, e.g. on the deck 3, to the pile driving position thereof. This pile driving position is shown in FIG. 11. Thereto the lifting tool 6 suspended from the crane 4 is moved such that it approaches the connectors 11n of the support structure of the pile driving system 7 in the storage position, after which these are engaged and connected by the lifting tool 6 such as to suspend the pile driving system 7 from the crane 4. This connection is shown in the magnification shown in the left-top part of FIG. 11. The crane 4 then moves, e.g. by revolving the boom around the vertical axis and pivoting it around the horizontal axis, the pile driving system 7 from the storage position into the pile driving position thereof, after which the pile driving system 7 is disconnected from the lifting tool 6.

[0210] In a possible method for pile driving, e.g. a method including the abovementioned steps of connecting and moving the pile driving system from the storage position to the pile driving position, the pile 1 is driven into the soil by a repeated cycle. This repeated cycle comprises firstly the step of lifting the drop weight assembly 10 by means of the lift system 20 into a desired initial height position.

[0211] This initial height position of the drop weight assembly 10 is shown in FIG. 12a, and in FIG. 4. The repeated cycle comprises secondly the step of operating the quick release mechanism 25 to effect quick release of the lift system 20, so that the drop weight assembly 10 falls down from said initial height position towards the drive head member 3 due to gravity. The final position of the drop weight assembly 10 is shown in FIG. 12b, and in FIG. 5.

[0212] The repeated cycle may be executed without any solid drop weight elements 12s, 12a-c being stacked on the support structure 11, as in FIGS. 12a, 12b so that the drop weight assembly consists of the support structure only. The repeated cycle may also be executed with a desired number of sets of solid drop weight elements stacked thereon.

[0213] In a possible method for pile driving, the method comprises employing the crane 4 to move sets of drop weight elements 12a-c, 12s from a storage position thereof, e.g. on the deck 3, as shown in FIGS. 10-13, to the functional position thereof in which the set of solid drop weight elements is stacked onto the support structure 11 of the pile driving system 7, which is in the pile driving position thereof.

[0214] FIG. 12c,d,e illustrate the lifting tool 6 approaching, engaging and connecting to the uppermost set of drop weight elements 12a-c, 12s on the stack of drop weight elements 12a-c, 12s in the storage position. These steps may e.g. be performed during a repeated cycle as discussed above, which is illustrated in FIG. 13.

[0215] As shown in FIGS. 12c,d,e the lifting tool 6 is brought with the positioning arms 6a thereof into engagement with the pylons 13, so that the tool 6 becomes properly aligned with the connectors 11n that are to be coupled to the tool 6.

[0216] FIG. 14 illustrates the crane 4 being operated while the set of drop weight elements 12a-c, 12s is being lowered to the functional position thereof. FIG. 14 illustrates, from top to bottom, that the set approaches the vertical guide members 13 while vertically aligning the openings of the drop weight elements 12a-c, 12s of the stack therewith, that the leftmost openings are placed around the leftmost guide member 13 and consequently the rightmost openings around the rightmost guide member 13, and that the set is lowered towards the platform of the support structure 11 while being guided by the guide members 13.

[0217] In a possible method, the repeated cycle is executed first without any solid drop weight elements being stacked on the support structure 11. This is done e.g. while driving a lower end section of the pile 1 into an uppermost layer of the soil. Usually, driving the pile 1 deeper into the soil requires a greater amount of energy per stroke of the drop weight. The first repeated cycle, without drop weight elements, may thereto e.g. be executed until a predetermined threshold for the blow energy required is reached, after which one or more sets of solid drop weight elements are stacked on the support structure 11 to be added to the drop weight assembly 10, in the way described above. After this the repeated cycle is executed for the second time. This may be repeated a couple of times until the required penetration depth of the pile 1 is reached. So, the second repeated cycle with solid drop weight elements may again be executed until reaching a threshold, e.g. the impact energy threshold, one or more further sets of solid drop weight elements may be added to the drop weight assembly 10. The cycle may again be executed with the increased mass of the drop weight assembly, one or more further sets of drop weight elements may be added to further increase the mass of the drop weight assembly, and so on.

[0218] In stacking the sets of solid drop weight elements, the tool 6 is rotated back and forth in each consecutive cycle by 90°, to accomplish the earlier mentioned configuration of the sets within the stack on the support structure. In a possible method, after reaching the desired penetration depth, the sets of solid drop weight elements may be moved by the crane 4 to the storage position thereof, while again rotating the tool by 90° back and forth between moving each consecutive set. The pile driving system 7 may be moved to the storage position as well.

[0219] In FIG. 16 it is shown that a pile 1, e.g. a hollow and open ended pile, e.g. a large diameter pile 1 having an outer diameter of at least 5 meters, e.g. a monopile of a wind turbine, is driven into the soil, e.g. into the seabed.

[0220] The pile driving system comprises: [0221] a drive head member 8 that is configured to engage the pile, e.g. is configured to be arranged on the top end of the pile 1, [0222] a liquid fillable drop tank 110, that has a capacity to hold at least 50 m3, preferably at least 100 m3, e.g. more than 500 m3, e.g. more than 1000 m3, of a liquid therein and that is vertically mobile relative to, here above, the drive head member 8, [0223] a lift system 20, arranged between the drive head member 2 and the liquid filled drop tank 110, that is configured to bring the liquid filled drop tank into an initial height position relative to the drive head, [0224] a quick release system 25 that is adapted to effect quick release of the lift system so that the liquid filled drop tank falls down from said initial height position, [0225] an energy transfer assembly 30 configured for transfer of energy from the falling liquid fillable drop tank 110 to the drive head member 8.

[0226] The tank 110 is provided with members 111, e.g. screens, that reduce or avoid sloshing of the liquid, e.g. water, e.g. seawater, in the tank.

[0227] As explained herein with reference to the second aspect of the invention, for driving the pile 1 into the soil, the drop tank 110 is at least partially filled with liquid, e.g. water, e.g. seawater, to set the weight of the drop tank.

[0228] The method comprising a repeated cycle wherein: [0229] the liquid filled drop tank 110 is lifted by means of the lift system 20 into a desired initial height position, [0230] the quick release mechanism 25 is operated to effect quick release of the lift system so that the liquid filled drop tank 110 falls down from said initial height position towards the drive head member.

[0231] Herein energy from the falling liquid filled drop tank 110 is transferred by the energy transfer assembly 30 to the drive head member 8 and thereby to the pile 1, here to the top end of the pile, so that the pile 1 is driven deeper into the soil. This cycle is repeated till the desired penetration depth is reached.

[0232] As explained it is envisaged that the energy transfer from the drop tank 110 to the pile drive head 8 is devoid of mechanical impact energy transfer between the drop tank 110 and drive head. As shown here the energy transfer assembly is devoid of an anvil.

[0233] The energy transfer assembly 30 comprises one or more spring devices and/or one or more damper devices, e.g. embodied like the mentioned oleo-pneumatic integrated spring and damper devices. These devices are here mounted on the drive head 8 in a circular or other shaped array and are effective between the drop tank and the drive head member.

[0234] The pile 1 here has an open foot end and an outer diameter of at least 5 meter, e.g. of between 5 and 12 meters. Preferably the pile 1 is hollow over its length.

[0235] The liquid fillable drop tank 110 has a capacity to hold at least 100 m3, preferably at least 500 m3, e.g. more than 1000 m3 or more than 2000 m3, of a liquid therein. For example, the tank has a diameter within 0.5 and 1.5 times the outer diameter of the pile 1, e.g. of between 1.0 and 1.5 times the outer diameter of the pile 1.

[0236] In embodiments, the energy transfer system 30 comprises multiple gas spring devices, e.g. telescopic devices, each comprising a compressible gas filled variable volume chamber that is compressed with resultant increase of gas pressure upon compression of the liquid filled variable volume chamber by the falling drop tank.

[0237] In embodiments, the energy transfer system 30 comprises multiple liquid damper devices, e.g. telescopic devices, each comprising a liquid filled variable volume chamber and an associated liquid flow resistance through which at least a part of said liquid is forced upon compression of the liquid filled variable volume chamber by the falling drop tank.

[0238] It is illustrated here that the energy transfer system 30 comprises multiple integrated spring and damper devices 31, these multiple integrated spring and damper devices 31 being arranged in a circular array on the drive head member 8. These devices are vertically telescopic to form one or more chambers for gas and for damping liquid.

[0239] Instead of, or in combination with, damping using liquid damping other damping devices can be applied, e.g. based on mechanical friction.

[0240] As explained each integrated spring and damper device 31 may comprises a compressible gas filled variable volume chamber that is compressed with resultant increase of gas pressure upon compression of the liquid filled variable volume chamber by the falling drop tank and each integrated spring and damper device comprises a liquid filled variable volume chamber and an associated liquid flow resistance through which at least a part of said liquid is forced upon compression of the liquid filled variable volume chamber by the falling drop tank.

[0241] Reference numeral 140 denotes a vertical guide structure that is configured to vertically guide the drop tank 110 relative to the drive head 8. Here a telescoping guide member is provided that is vertically guided relative to the drive head 8. For example, the telescoping guide member comprises an annular guide member surrounding the drive head 2 and having a section protruding above the drive head.

[0242] It is illustrated that the one or more spring devices and/or one or more damper devices, e.g. embodied as integrated spring and damper devices 31, are arranged on the drive head member 8, each device 31 engaging at a lower end thereof the drive head 2 and each engaging at an upper end thereof the telescoping guide structure 140, e.g. being connected thereto.

[0243] It is illustrated here that an array of multiple spring devices and of multiple damper devices, e.g. embodied as multiple integrated spring and damper devices 31, is arranged within the annular guide member 140.

[0244] As preferred, the lift mechanism comprises multiple hydraulic lift cylinders 21. The quick release system 25 comprises one or more quick release valves 26 that are opened to allow rapid discharge of hydraulic liquid from the lift cylinders. As preferred the hydraulic liquid of the one or more lift cylinders 21 is circulated through a heat exchanger system so as to cool the hydraulic liquid, e.g. said heat exchanger being fed with seawater for cooling the circulated hydraulic liquid in case the pile is installed into the seabed.

[0245] As preferred, the liquid of the multiple liquid damper devices 31 is circulated through a heat exchanger system so as to cool said liquid, e.g. a volume of liquid in the circulation circuit being at least 10 times greater than the volume of the liquid filled variable volume chambers of the multiple liquid damper devices, e.g. the heat exchanger being fed with seawater for cooling the circulated damper liquid in case the pile is installed into the seabed.

[0246] Whilst the figure illustrates that the tank 110 is embodied with a single cavity for storage of the liquid, an alternative design provides for the liquid fillable drop tank to comprise a group of tank members, e.g. a group of pipe sections, e.g. cylindrical pipe sections, the group of tank members being mounted on a common tank frame, each tank member being fillable with a volume of liquid.

[0247] FIG. 17 shows a pile driving method and system having many similarities with the system of FIG. 16, the same components being denoted with the same reference numerals.

[0248] The pile driving system further comprises one or more telescoping fuel combustion operated devices 150 arranged to be effective between the drop tank and the drive head and, in operation, providing a fuel combustion based blow onto the drive head 8 in addition to the energy transferred from the falling drop tank 110. In practical embodiments, the pile driving device comprises a telescoping fuel combustion operated device having a first combustion chamber member 151 mounted to the drive head, and a second combustion chamber member 152 mounted to the drop tank, the first and second combustion chamber member being vertically telescoping relative to one another. A supply 153 of fuel and air 154, or of a fuel/air mixture are envisaged as well as an igniter 155 to ignite the fuel/air mixture in the telescopic combustion chamber. As a result of ignition the fuel/air mixture will combust, preferably very fast as a sort of detonation. The sudden increase of pressure in the chamber causes an impulse downward on the pile 1, as the upward resultant is absorbed by the mass of the drop tank. In embodiments ignition is timed just before, during, or just after the falling of the drop tank.

[0249] In embodiments with one or more telescoping fuel combustion operated devices as indicated above, the energy transfer onto the pile can be shaped even more than with just the provision of the drop tank. For example, the ignition, as well as the combustive power of the fuel/air mixture, can be adjusted to obtain first a short impulse onto the pile 1, followed by a longer duration transfer of energy from the falling drop tank 110 (which may have been released right at the moment of ignition or at another suitable moment in view of the desired profile of the force onto the pile by the pile driving system).

[0250] In embodiments, combustion gas can readily leave the telescopic chamber via one or more vent openings, possibly a vent opening 156 being permanently present between the first and second combustion chamber members 151, 152. In an embodiment venting of combustion gas from the combustion chamber is controlled by a controllable vent valve 157. The latter may, in embodiments, allow for keeping the combustion chamber in an enclosed telescopic combustion chamber member for a while after ignition, e.g. so that the combustion gas acts as a gas cushion for the falling drop tank.

[0251] In embodiments, it is envisaged that the power of the combustion is selected such that the drop tank is not lifted due to the combustion. As indicated above, ignition may be timed to occur during the actual fall of the drop tank, e.g. during the falling drop tank already interacting with the associated spring devices and/or damper devices.