Large diameter pile driving method and system

Abstract

A large-diameter steel pile (1) is driven vertically into the ground using a pile driver (10) on the top end of the pile. The pile driver includes a driving head assembly (20) having an annular contact surface (21) that rests on the top end of the pile and an annular anvil surface above the annular contact surface. A steel impact weight (30) has a mass of at least 100 tons. The impact weight (30) is lifted to a desired initial height by a lift system (60). A quick-release mechanism (70) is operated to quickly release the lift system so that the impact weight drops from the initial height onto the anvil surface (22) of the driving head assembly (20). The impact weight includes, and is preferably embodied as, a tubular impact weight made of steel.

Description

[Technical Field]

[0001] The present invention relates to the field of driving large diameter hollow open-ended steel piles vertically into the ground, the piles having a cylindrical top with a top wall thickness between the inner and outer diameters, the outer diameter extending at least 5 meters into the soil. The invention is particularly useful in driving monopiles for offshore wind turbines into the seabed. Practical embodiments currently envisaged include monopiles with diameters between 5 and 12 meters and lengths between 60 and 120 meters. Monopiles can weigh more than 1000 tonnes, with monopiles weighing approximately 2500 tonnes (12 meter outer diameter, 120 meters long) currently being proposed. [Background technology]

[0002] Currently, in practice for installing monopiles, a single so-called accelerating hydraulic hammer is commonly used, which is a pile driver in which an impact weight is accelerated downward by gas pressure via a hydraulic device to reach accelerations significantly greater than 1 g (the normal acceleration under gravity). These known devices allow accelerations of up to twice the free fall, i.e., up to 2 g. Although such piling devices, for example the Menck MHU 4400S, or the IQIP IQ4 or IQIP IQ6 hammers, are currently available in configurations capable of delivering more than 4000 kJ per blow, and even up to 5500 kJ per blow, their practical use for driving large diameter monopiles appears to suffer from various drawbacks.

[0003] In a practically known application for driving monopiles into the seabed, a single hydraulic hammer is placed in the center of the head-end assembly with its contact surface against the top of the monopile. The head-end assembly has a very rigid disk-shaped portion that distributes the impact energy from the anvil surface in the center of the head-end assembly to an annular contact surface with a diameter that is the same as the diameter of the top end of the monopile. This requires a very robust design of the head-end assembly.

[0004] Another approach to driving large diameter piles, e.g., monopiles, is proposed in US Pat. No. 5,623,999. In this patent, multiple hydraulic hammer pile driving devices are arranged on a single monopile. Each device has its own impact weight and an associated acceleration mechanism based on gas pressure acting on the impact weight via a hydraulic device. Each hammer is mounted on the open top section of the pile. This approach requires strict synchronization of the hammer devices, which is impractical.

[0005] An alternative approach for driving large-diameter piles is proposed in U.S. Patent No. 5,627,493. In U.S. Patent No. 5,627,493, the drop weight is subjected to gravity alone, i.e., falls at 1 G. In an embodiment, a single drop weight used for driving the pile has a mass of at least 50 tons, e.g., 100 tons, or even several hundred tons. In an embodiment, the drop weight comprises a support platform on which steel weight elements are stacked. The platform is guided by a vertical pylon. In an embodiment, the drop weight assembly is lifted by a lift system including multiple hydraulic lift cylinders and associated hydraulic pumps. A quick-release system includes one or more quick-release valves that open to allow rapid drainage of hydraulic fluid from the lift cylinders. The hydraulic fluid in the one or more lift cylinders can be circulated through a heat exchanger system to cool the hydraulic fluid; for example, the heat exchanger is supplied with seawater to cool the circulating hydraulic fluid when the pile is installed on the seabed. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2006 / 010758 [Patent Document 2] International Publication No. 2020 / 153838 [Patent Document 3] U.S. Patent No. 4,601,349 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention aims to provide an alternative pile driving device for driving large diameter piles into soil, for example monopiles into the seabed. In particular, the present invention aims to provide a pile driving device that is of limited complexity (e.g. in terms of manufacturing), highly reliable and / or easy to integrate into the overall monopile installation process. [Means for solving the problem]

[0008] According to its first aspect, the present invention proposes a pile driving method for vertically driving a hollow, open-ended, large-diameter steel pile into the ground, the pile having a cylindrical top with a top wall thickness between an inner diameter and an outer diameter, said outer diameter being at least 5 meters, e.g. a monopile for an offshore wind turbine, into the soil, e.g. into the seabed, A pile driving device is used, which is placed at the top end of the pile, and this pile driving device a driving head assembly having an annular contact surface that rests on the top end of the pile and an annular anvil surface above the annular contact surface; a steel impact weight having a mass of at least 100 tons, e.g., greater than 200 tons, the impact weight being vertically movable above the annular anvil face of the driving head assembly; a vertical guide structure configured to vertically guide the impact weight, wherein the driving head assembly is configured for an energy transfer assembly between the annular anvil surface and the annular contact surface for transferring energy from the falling impact weight to the annular contact surface and, therefore, to the pile top; a lift system configured to bring the impact weight to an initial height position relative to the annular anvil face of the driving head assembly; a quick release system adapted to quickly release the lift system so that the impact weight drops from the initial height position onto the anvil face of the driving head assembly; Including, This method is The impact weight is raised to an initial height position by the lift system, a quick release mechanism is operated to quick release the lift system so that the impact weight falls from the initial height position onto the anvil face of the driving head assembly, and energy from the falling impact weight is transferred by the energy transfer assembly to the contact face of the driving head assembly and thus to the top end of the pile, causing the pile to be driven deeper into the soil; Contains repeating cycles.

[0009] According to a first aspect of the invention, the impact weight comprises or is embodied as a tubular impact weight made of steel.

[0010] In an embodiment, the tubular impact weight has an inner diameter and an outer diameter such that, in vertical projection, the tubular impact weight overlaps with the wall thickness of the top of the pile. This arrangement ensures that the impact energy of the falling impact weight passes vertically through the head-end assembly and then transfers to the wall thickness of the top of the (mono)pile. This avoids excessive stress in the path of the impact energy and allows for optimal driving efficiency.

[0011] In an embodiment, an acceleration mechanism is provided that accelerates a falling weight downward at an acceleration greater than 1 G, for example, adjustable between 1 G and 2 G. For example, a pile driving device is provided with multiple acceleration devices arranged in a circular array and engaging a tubular impact weight at distributed positions. For example, each of the multiple acceleration devices is based on the acceleration known from the aforementioned hydraulic hammer, as shown in Patent Document 3. For example, each acceleration device includes a cylinder having a cylinder body and a piston / piston rod, and a pressurized gas-filled chamber urges the piston / piston rod downward. Compared to the disclosure of Patent Document 1, in which each acceleration hammer device has its own impact weight, the multiple acceleration devices here engage a common impact weight. This is advantageous in terms of synchronization, as the acceleration devices are mechanically coupled via a sturdy impact weight.

[0012] In an embodiment, the pile driving device lacks an acceleration mechanism, allowing the impact weight to fall under gravity without further acceleration. Compared to accelerated embodiments, this gravity-based fall in the inventive concept allows for a relatively longer duration of energy transfer. This can improve pile driving efficiency and contribute to reducing pile driving noise, which is particularly important in offshore pile driving.

[0013] Preferably, the impact weight is embodied as a tubular impact weight made of steel, for example cast or welded from steel sheet, for example a semicircular steel sheet welded together, for example having a wall thickness of between 10 and 20 centimeters.

[0014] In embodiments, the tubular impact weight has a circular cross section, e.g., made of semicircular steel plates welded together. In other embodiments, the tubular impact weight has a polygonal cross section, e.g., made of flat plates welded together to form a polygon with 16 or 32 sides.

[0015] Preferably, the steel tubular impact weight has an inner and outer circumferential side, a wall thickness between the inner and outer circumferential sides, and is therefore made of solid steel between the inner and outer circumferential sides.

[0016] In one embodiment, the tubular impact weight has a lower section of a first wall thickness and an upper section of a second wall thickness, the second wall thickness being greater than the first wall thickness.

[0017] Preferably, the lift system is connected to the upper portion of the tubular impact weight, for example a lift cylinder having a piston rod one end of which is connected to the upper section of the tubular impact weight.

[0018] Preferably, the tubular impact weight is free of internal bracing members extending across the opening defined by the tubular impact weight, thereby avoiding excessive local stresses, for example, where such bracing members abut the tubular portion.

[0019] In an embodiment, the tubular impact weight has an inner diameter and an outer diameter such that, in vertical projection, the tubular impact weight overlaps with the wall thickness of the top of the pile. This arrangement ensures that the impact energy of the falling impact weight passes vertically through the head-end assembly and then transfers to the wall thickness of the top of the (mono)pile. This avoids excessive stress in the path of the impact energy and allows for optimal driving efficiency.

[0020] In a practical embodiment, as in the prior art, the top of the pile is open just like the bottom.

[0021] In an embodiment, the tubular impact weight is hollow and open ended, effectively embodied as a solid steel impact weight ring.

[0022] In an embodiment, the driving device including the tubular impact weight has a central passage with an open end, for example allowing access to the inside of the monopile from above through the driving device. Preferably, the central opening has a diameter of at least 2 meters, for example corresponding to 50%, for example at least 75%, of the inside diameter of the top of the pile. This allows sufficient access to the inside of the monopile from above through the driving device, which may be practically beneficial.

[0023] For example, during pile driving or in subsequent steps before removing the pile driving equipment from the (mono)pile, other operations are performed that involve accessing the inside of the pile through this central passage. For example, the central passage is used to provide access to the inside of the pile for one or more of the following equipment: jetting equipment, soil removal equipment, excavation equipment, vibrating equipment, grouting equipment, including the piping associated with such equipment. For example, this passage is used to provide access to stone removal equipment when the pile hits a large stone, for example, during pile driving.

[0024] For example, a center gangway may be used to lower drilling equipment along a pile to the seabed. This is particularly advantageous when the pile hits a large rock embedded in the seabed during a piling operation. Typically, the pile must be lifted and removed from its location so that the rock or other obstruction can be removed using drilling equipment. By having a center gangway, drilling equipment can be lowered to the seabed to remove the obstruction without having to lift and remove the pile.

[0025] For example, the central passageway may be used to engage a pile lifting tool with the top of the pile, the pile lifting tool being configured to be introduced into the central passageway and then engage the top of the pile.

[0026] For example, the pile has an inward facing top flange with, for example, bolt holes. Preferably, the contact surface is located directly above the top wall of the monopile to avoid (undue) strain on the top flange during pile driving.

[0027] For example, during a pile run, if the pile driver is closed, as the pile advances deeper into the seabed, all the air inside the pile and the pile driver will be compressed, causing an increase in pressure inside the pile and the pile driver. This pressure can become high enough to lift the pile driver off the top of the pile, which can cause serious damage to the pile driver, the pile, and surrounding structure, as well as being dangerous to workers. Having a central passage with an open end allows air to exit the pile and the pile driver so that pressure does not build up, increasing safety during the operation.

[0028] For example, a central passageway can be used to reduce the chance of pile run. The central passageway allows for the use of pile run prevention members, which can be positioned inside the central passageway and are configured to engage flanges at the top ends of the piles.

[0029] In one embodiment, the pile run prevention member includes a damping member suspended from the pile driver, or optionally a crane, and an engagement member suspended from the damping member and configured to engage an inwardly facing top flange of the pile.

[0030] In an alternative embodiment, the pile run prevention member is embodied as a cable having a first end and a second end, the first end being suspended from the pile driver, or optionally from a crane, and the second end being provided with an engagement member configured to engage with an inward-facing top flange of the pile, wherein during normal operation the cable is slack, and as the pile is driven deeper into the ground by the pile driver, the length of the cable increases so that the cable does not exert force on the pile, and only when a pile run occurs does the cable become taut and exert an upward force on the pile to prevent pile run.

[0031] In embodiments, the driving head assembly is configured to expose a portion of the inwardly facing top flange. This arrangement may, in embodiments, allow the flange to be gripped by a gripper of a pile lifting tool. In embodiments, the driving head assembly has an inner diameter that is larger than the inner diameter of the inwardly facing top flange so that a peripheral edge of the flange is exposed.

[0032] In an embodiment, the tubular impact weight has a wall thickness between 10 and 20 centimeters.

[0033] In an embodiment, the tubular impact weight has a height of between 4 and 12 meters, for example between 6 and 10 meters, and preferably the tubular impact weight has a wall thickness of between 10 and 20 centimeters.

[0034] In an embodiment, the lifting means is configured so that the vertical distance between the anvil face and the initial height of the impact weight is at most 2 metres, for example about 1 metre.

[0035] In an embodiment, the piling device has an outer housing extending coaxially around a tubular impact weight, the outer housing having an open lower end that mounts to the driving head assembly.

[0036] Preferably, the outer housing is closed at its periphery.

[0037] In a practical embodiment, the outer housing has an open top end and a central passageway whose diameter corresponds to at least 50%, more preferably at least 75%, of the inside diameter of the top of the pile.

[0038] In a practical embodiment, the lift mechanism comprises a plurality of hydraulic lift cylinders.

[0039] In an embodiment, as generally disclosed in, for example, U.S. Patent No. 5,929,999, the lift cylinder is integrated with an acceleration mechanism that accelerates the drop weight downward at an acceleration greater than 1 G, for example, adjustable between 1 G and 2 G.

[0040] Preferably, the hydraulic lift cylinders are arranged in a circular array above the tubular impact weight, more preferably so as to leave open a central passageway of a diameter corresponding to at least 50%, more preferably at least 75%, of the inside diameter of the top of the pile.

[0041] In a practical embodiment, the quick release system includes one or more quick release valves that are opened to allow rapid drainage of hydraulic fluid from the lift cylinders. For example, the lift cylinders are connected to a common hydraulic drain duct assembly controlled by a single quick release valve, or two sets of lift cylinders are connected to respective common hydraulic drain duct assemblies, each controlled by a respective quick release valve. These measures can reduce the delay in draining hydraulic fluid from one lift cylinder relative to one or more other lift cylinders.

[0042] For example, a plurality of hydraulic lift cylinders are located on top of the outer housing, for example, on an inward flange of the outer housing.

[0043] In one embodiment, the vertical guide structure includes an impact weight engagement member configured to engage, for example, a tubular impact weight on an exterior thereof, and preferably the impact weight engagement member is configured to engage the impact weight with a preload.

[0044] In a practical embodiment, the vertical guide structure includes roller assemblies, each of which includes one or more horizontal axis rollers that engage, for example, a tubular impact weight on its exterior. For example, the roller assemblies are mounted on an outer housing. For example, there is a lower group of roller assemblies and an upper group of roller assemblies, and the vertically movable impact weight is always guided by the roller assemblies of these lower and upper groups.

[0045] In an embodiment, the roller assembly is configured to preload one or more rollers against the tubular impact weight, for example, to provide accurate vertical guidance and / or to absorb peak loads caused by rebound of the impact weight.

[0046] In an embodiment, the driving head assembly includes a resilient material cushion member, for example, an annular resilient material cushion member, disposed between the anvil face and the contact surface.

[0047] In embodiments, the energy transfer assembly of the driving head assembly includes one or more spring devices and / or one or more damper devices active between the anvil face and the contact surface, the one or more spring devices and / or one or more damper devices configured to increase the duration of energy transfer, thereby increasing efficiency and reducing noise generation.

[0048] In embodiments, the driving head assembly includes a plurality of spring devices and / or a plurality of damper devices, for example embodied as an integrated spring and damper device, arranged in a circular array within the driving head assembly.

[0049] In an embodiment, the driving head assembly includes a plurality of cylinder devices arranged in a circular array on the driving head assembly, each cylinder device having a cylinder body, a piston, and a chamber separated by the piston, the chamber being filled with a liquid and / or gas, e.g., oil, and optionally the chambers of the cylinder devices being interconnected.

[0050] In one embodiment, a plurality of cylinder devices are arranged in a circular array on the driving head assembly, the cylinder devices being disposed between an annular anvil member defining the anvil face and a bottom member defining the contact surface, and the cylinder devices are fabricated from a metal, such as steel or titanium.

[0051] In one embodiment, a plurality of cylinder devices are evenly distributed around the circumference of and on the top flange of the pile, each cylinder device having an anvil member at its top end and a bottom member that forms the contact surface between the cylinder device and the top flange of the pile.

[0052] In one embodiment, the cylinder device includes a cylinder body, a piston, and a single chamber bounded by the cylinder body and the piston. Preferably, the chamber is filled with a liquid, and preferably oil is used to fill the chamber due to the relatively high elasticity of oil compared to, for example, water.

[0053] Preferably, the piston is embodied as a hollow piston. The piston has a central cavity extending from an open bottom end to a closed top end of the piston. The central cavity is bounded by an annular piston wall and a top piston wall. The central cavity forms part of a single chamber. The use of a hollow piston reduces the weight of the piston and increases the volume of the liquid, e.g., oil, which leads to improved energy transfer efficiency.

[0054] In one embodiment, the bottom end of the piston wall is chamfered. During pile driving, as the oil is compressed, the piston displaces through the oil very quickly, which can create a cavitation zone near the bottom end of the piston wall, which can cause oil degradation and reduce energy transfer efficiency. By using a chamfered bottom end of the piston wall, the piston can displace through the oil more easily, e.g., the piston wall is more pressure dynamic, which reduces the chance of creating a cavitation zone in the oil.

[0055] In one embodiment, a resilient compressible element is disposed on the top end of the piston. This element is embodied to act as a cushion, for example, a slab or disk of resilient compressible material, or a metal element, such as one or more disc springs. By providing this element on the piston so as to act between the piston and the impact weight, the piston accelerates more slowly than would occur without such an element.

[0056] In an embodiment, the piling device includes a sleeve that extends from the head end assembly down along the top section of the piling.

[0057] In one embodiment, the pile driving device is connected to a lifting tool of a crane during pile driving, and a plurality of shock absorbers are mounted on the top of the pile driving device, e.g., on its outer housing, and these plurality of shock absorbers are connected to a spreader structure, e.g., two shock absorbers are connected at their top ends to a spreader bar, and the spreader structure is connected to the lifting tool, e.g., via two slings.

[0058] In one embodiment, the method is carried out at sea, for example for the installation of monopiles, using a vessel including a pile gripping device, for example a motion compensated pile gripper, which operates to hold the pile vertically during pile driving.

[0059] In an embodiment, a vibrating device is used in conjunction with a piling device.

[0060] For example, the vibration device is configured to vibrate the pile about its vertical axis and generate alternating forces about the axis at a vibration frequency to reduce friction between the pile and the soil, e.g., the seabed.

[0061] For example, the vibration device may be configured to generate vertical vibrations to drive the pile into the soil, which in embodiments may be combined with vibrations about the pile's vertical axis to reduce friction between the pile and the soil, e.g., the seabed.

[0062] For example, because the vibratory device is mechanically separated from the piling device described herein, the vibratory device is not subject to, or is subject to, limited impact caused by the impact weight.

[0063] For example, the vibratory device may be configured to be mounted within the top of the pile, e.g., prior to placing the pile driver on the pile. When present, the central passage of the pile driver may provide access to the vibratory device, e.g., for hydraulic lines supplying hydraulic fluid to the motor of the vibratory device, e.g., in terms of supplying energy to the vibratory device.

[0064] For example, the vibratory device is supported by a floating support configured to allow a range of floating movement along the vertical axis of the vibratory device to prevent impacts applied by the pile driver from being directly transmitted to the vibratory device. For example, the floating support is configured to dampen impact forces, for example, one or more elastic bodies, such as one or more springs or cylinders, are provided to support the vibratory device in the vertical direction.

[0065] For example, the vibrating device may be connected to an inward flange of the pile and / or clamped inside the top of the pile, for example using a hydraulic friction clamp, such as a wedge clamp.

[0066] For example, the vibrating device is only connected to the pile when the pile driver is not impacting the pile, which avoids excessive mechanical loads on the vibrating device.

[0067] For example, a vibrating device may be used in the first stage of driving the pile into the soil, and a pile driver with impact weights may be used in the second stage of driving the pile into the soil, thereby reducing the overall noise generation of, for example, the (mono)pile installation.

[0068] For example, the vibrating device is independently suspended and not mechanically attached to the piling device. For example, the vibrating device is suspended from a crane, e.g., the same crane from which the piling device is suspended, e.g., via the shock absorbers and possibly the spreader structure described above. Optionally, the vibrating device is suspended from the spreader structure, e.g., via a winch arrangement, as discussed herein.

[0069] In one embodiment, the lower portion of the impact weight includes one or more spring devices and / or one or more damper devices that contact the anvil face.

[0070] In one embodiment, the impact weight includes holes extending from the bottom of the impact weight along its height, the holes being distributed around the circumference of the impact weight. The length of the holes is between 50% and 90% of the impact weight's height, preferably between 60% and 80% of the impact weight's height. An elongated member, such as a bar or rod, is received inside the hole and extends along the entire length of the hole, with the lower end of the elongated member extending beyond the bottom of the impact weight and contacting the anvil face. Due to the length of the elongated member, it acts like a spring, thereby increasing the duration of energy transfer, increasing efficiency, and reducing noise generation. For example, the elongated member is received in the hole with some play.

[0071] Due to the size, shape, and material of the impact weight, it is difficult to manufacture an impact weight that includes only one piece. To make the impact weight manufacturing process easier and faster, the impact weight can be made in multiple pieces, which are then connected to form the impact weight.

[0072] In one embodiment, the impact weight includes two or more ring members, e.g., each made of steel, e.g., cast steel or welded steel, stacked together to form the impact weight. In one embodiment, each ring member of the impact weight includes two or more ring segments, e.g., semicircular ring segments, e.g., more than four ring segments, which together make up the ring member.

[0073] In one embodiment, the ring members, eg, ring segments thereof, are vertically connected to one another using vertical fasteners, eg, bolts.

[0074] In one embodiment, the impact weight includes two or more ring members stacked on top of one another, each ring member including two or more ring segments, with the ring segments of adjacent ring members circumferentially offset so that each ring segment overlaps at least two adjacent ring segments. Vertical fasteners, such as long bolts, can extend through holes aligned with the ring segments to interconnect the ring segments and ring members to form the tubular impact weight.

[0075] In one embodiment, adjacent ring segments are welded together to form ring members, and the ring members are interconnected by vertical fasteners that extend through aligned holes in the ring members.

[0076] When the impact weight falls and contacts the anvil face of the driving head assembly, it tends to expand radially, e.g., downward, which creates significant tangential stresses on the impact weight. These repeated tangential stresses on the impact weight can cause fatigue, which can lead to damage and failure. To reduce the tangential stresses, the impact weight can be embodied with multiple regions that provide flexibility in the tangential direction. The tangential flexibility in these regions allows the impact weight to expand more freely upon contact with the anvil face, thereby reducing peak tangential stresses. Multiple impact weight embodiments are envisioned to achieve these tangentially flexible regions.

[0077] In one embodiment, the impact weight includes two or more ring segments, such as arc segments or quadrilateral segments, where adjacent segments are connected to each other by a resilient region, also referred to as a spring zone, which may fill the gap between adjacent ring segments and may be embodied, for example, as a folded steel piece.

[0078] In one embodiment, the impact weight includes one or more ring members each assembled with two or more ring segments, e.g., arc segments or quadrilateral segments, the ring segments having an inner wall surface, an outer wall surface, and a wall thickness, adjacent ring segments connected to each other by welding, e.g., vertical welds, the welds in the ring members extending alternately from the inner wall surface and the outer wall surface, and each of the welds extending only partially between the inner wall surface and the outer wall surface such that a groove extends at the junction of the ring segments.

[0079] Tangential stresses caused by the impact weight's fall can cause structural damage, particularly at the impact weight's circumferential welds, which typically have less resistance to stress and fatigue than the rest of the impact weight. To reduce the stresses acting on the circumferential welds, the impact weight includes multiple quadrilateral segments that form a polygon, thereby reducing the stress on the circumferential welds by locating them farther away from high-stress areas.

[0080] For example, the segments may be embodied as quadrilateral segments, such that two or more segments form a polygon, for example a hexagon made up of 16 quadrilateral segments.

[0081] In one embodiment, the impact weight includes a single circular segment having an inner wall surface and an outer wall surface, for example, the single circular segment having axial slots evenly distributed along the radius and height of the impact weight.

[0082] The present invention will now be described with reference to the drawings. [Brief explanation of the drawings]

[0083] [Figure 1A] 1 is a vertical cross-sectional view of a portion of a monopile and pile driving rig according to a first embodiment of the present invention; FIG. [Figure 1B] FIG. 1B is an enlarged view of a portion of FIG. 1A. [Figure 2] FIG. 2 is a top view of the arrangement of FIG. 1. [Figure 3] FIG. 2 shows a tubular impact weight of the pile driving device of FIG. 1. [Figure 4] 2 shows the outer housing of the pile driving device of FIG. 1. FIG. [Figure 5] FIG. 2 shows a head end assembly of the piling device of FIG. 1. [Figure 6a] FIG. 2 shows a roller assembly of the piling device of FIG. 1. [Figure 6b] FIG. 2 shows a roller assembly of the piling device of FIG. 1. [Figure 7] 2 is a diagram showing handling of the pile driving device of FIG. 1 by a crane. [Figure 8a] FIG. 1 illustrates another embodiment of a head-end assembly. [Figure 8b] FIG. 1 is a diagram illustrating an embodiment of a cylinder device. [Figure 9] 8b shows a vertical cross section of a portion of a monopile and piling rig including the head end assembly of FIG. 8a. [Figure 10] FIG. 1 shows a schematic diagram of an application of a vibration device. [Figure 11a] 13A-13C show alternative embodiments of tubular impact weights. [Figure 11b] 13A-13C show alternative embodiments of tubular impact weights. [Figure 11c] 13A-13C show alternative embodiments of tubular impact weights. [Figure 11d] 13A-13C show alternative embodiments of tubular impact weights. [Figure 11e] 13A-13C show alternative embodiments of tubular impact weights. [Figure 11f] 13A-13C show alternative embodiments of tubular impact weights. [Figure 11g] 13A-13C show alternative embodiments of tubular impact weights. [Figure 12a] FIG. 10 illustrates an embodiment of a pile-run prevention member including a damping member. [Figure 12b] FIG. 1 illustrates an embodiment of a pile run prevention member embodied as a cable having a first end and a second end. DETAILED DESCRIPTION OF THE INVENTION

[0084] A first embodiment of the present invention will be described with reference to Figures 1A to 7. The figures are to scale and show a monopile 1 having an outer diameter of 8 meters being driven into the seabed. The person shown in Figure 1A is only there as a reference to make it possible to understand the size of the components shown by way of example.

[0085] The monopile 1 is a large diameter hollow open-ended steel monopile 1 to be driven vertically into the seabed to serve as a foundation for an offshore wind turbine.

[0086] The pile may have a constant diameter along its length, but may also have another design. For example, the monopile may have a bottom portion of a first largest diameter, a tapered portion, and a top portion 1a of a second smallest diameter. For example, the second smallest dimension may be at least 5 meters, such as 8 meters as shown here.

[0087] The monopile 1 has a cylindrical top 1a with a top wall thickness between the inner and outer diameters. For example, as shown here, the wall thickness of the top 1a is 8 centimeters. The top is open at its top end.

[0088] The pile 1 has an inward facing top flange 1b with bolt holes here for connecting the mast of the wind turbine to the monopile 1.

[0089] As known in the art, monopiles can be between 60 and 120 meters long. Diameters at the base end between 8 and 12 meters are known or proposed. Monopiles can weigh well over 1000 tons, for example, between 2000 and 3000 tons. Wall thicknesses between 8 and 15 centimeters are known or proposed.

[0090] 1 to 7 show a pile driving device 10 configured to be placed at the top end of a pile 1. FIG.

[0091] The pile driving device 10 includes: a driving head assembly (20) having an annular contact surface (21) configured to rest on the top end of the pile (1) and an annular anvil surface (22) above the annular contact surface (21); a steel impact weight 30, in the illustrated example having a mass of approximately 200 tons, which is vertically movable above the annular anvil face 22 of the driving head assembly 20; a vertical guide structure (40) configured to vertically guide the impact weight (30), the driving head assembly (20) being configured to transfer energy between the annular anvil surface (22) and the annular contact surface (21) to transfer energy from the impact weight (30) to the annular contact surface (21) and thus to the pile top (1a); a lift system (60) configured to bring the impact weight (30) to an initial height position relative to the annular anvil face (22) of the driving head assembly (20); a quick release system adapted to quickly release the lift system so that the impact weight drops from the initial height position onto the anvil face of the driving head assembly; Includes.

[0092] The pile driving device 10 includes: The impact weight 30 is lifted to an initial height position by the lift system 60, the quick release mechanism 70 is operated to quickly release the lift system 60 so that the impact weight 30 falls from the initial height position onto the anvil face 22 of the driving head assembly 20, and energy from the falling impact weight 30 is transferred to the contact face 21 of the driving head assembly and thus to the top end of the pile, causing the pile to be driven deeper into the soil; It is capable of operating in repeated cycles.

[0093] As shown, the impact weight 30 is embodied as a tubular impact weight made of steel, which is hollow and open ended.

[0094] The wall thickness of the tubular impact weight 30 is, on average, somewhat greater than the wall thickness of the cylindrical wall of the top 1 a of the monopile 1 in order to obtain the desired weight of the impact weight 30 .

[0095] The height of the tubular impact weight 30 is greater than 4 meters, for example between 4 and 12 meters, for example between 6 and 10 meters. In the illustrated embodiment, with an 8 meter diameter top monopile and an 8 meter diameter impact weight, the height is about 7.5 meters.

[0096] The diameter of the tubular impact weight 30 corresponds approximately to the diameter of the monopile top 1a, so that the mass of the impact weight 30 is normally located in vertical projection onto the cylindrical wall of the top 1a, which allows optimal energy transfer.

[0097] The tubular impact weight has a diameter such that, in vertical projection, the tubular impact weight overlaps the wall thickness of the top 1a of the pile 1. The tubular impact weight has a wall thickness of between 10 and 20 centimeters.

[0098] As shown here, the contact surface 21 is positioned directly above the top wall 1a of the monopile 1 to avoid excessive distortion of the top flange 1b during pile driving.

[0099] It is shown that the driving head assembly 20 is configured to leave the peripheral edge of the inwardly facing top flange 1 b exposed, for example so that the bolt holes remain accessible. This arrangement may, in embodiments, allow for gripping of the flange 1 b by a gripper of a monopile lifting tool.

[0100] The lifting means 60 is configured so that the vertical distance between the anvil face 22 and the initial height of the impact weight 30 is at most 2 meters, here up to about 1 meter. The lifting means 60 is configured to adjust the initial height, for example up to a height of 1 meter, in order to adjust the energy per blow of the impact weight.

[0101] The piling device has an outer housing 50 that extends coaxially around the tubular impact weight 30. The outer housing has an open lower end where the driving head assembly 20 rests.

[0102] The outer housing 50 is made, for example, of welded steel.

[0103] The outer housing 50 has an open top end. Optionally, the open top end of the outer housing 50 has associated therewith a removable closure, such as a removable lid.

[0104] The outer housing 50 is closed around the periphery, for example to form a sound barrier. For example, although not shown, there is sound-insulating liner material on the sides of the housing to reduce noise generation from the housing 50 while the pile driving is taking place.

[0105] The outer housing 50 has an open top end and a central passageway whose diameter corresponds to at least 50%, more preferably at least 75%, of the inside diameter of the top of the pile.

[0106] The piling rig has an integrated lift acceleration mechanism 60 including a plurality of integrated lift acceleration devices 61. These devices are distributed, for example, on top of the outer housing 50, here in a circular array mounted on the inward-facing top flange 51 of the outer housing 50. For example, between six and twelve devices 61 are present on the outer housing 50. For example, the devices 2 may allow for an adjustable acceleration of the drop weight up to 2G. Greater accelerations are not excluded, but this would require a heavier design for the piling rig, for example its outer housing 50.

[0107] The device 61 is mounted vertically on the outer housing 50 .

[0108] The devices 61 are each connected to the top of a tubular impact weight 30 .

[0109] The device 61 includes a piston and a piston rod 62 extending downwardly from a cylinder body 63 that is fixed to the outer housing 50. The piston rod 62 has one end connected to the upper section of a tubular impact weight.

[0110] In this example, the impact weight 30 has a hole 31 along its upper edge, into which the clevis of the piston rod fits and which is connected to the impact weight 30 via a pin.

[0111] The lower chamber 64 defined by the piston is a hydraulic lift chamber. The upper chamber 65 defined by the piston is a pressurized acceleration chamber, filled with, for example, pressurized gas, for example, from a gas buffer 66. For example, as known in the art, a gas pressure regulating valve assembly is provided, which allows for setting a desired gas pressure and, therefore, a desired acceleration of the impact weight 30.

[0112] The chambers 64 of the device 61 may be connected to a common duct arrangement 67 for supplying hydraulic fluid to the chambers 64 and / or for quickly draining hydraulic fluid, e.g., water, from the chambers 64. For example, a common duct for a number of chambers 64, and possibly all chambers 64, is connected to one or more quick release valves 70 that are opened to allow quick draining of hydraulic fluid from the lift chambers 64 of the device 61. For the lift operation, a hydraulic system is provided that includes, for example, one or more hydraulic pumps 68.

[0113] In another embodiment, the quick release is embodied in the form of an operable connector device, such as a mechanical latch, a magnetic connector, a friction clamp, or the like, that connects the lift cylinder to the impact weight.

[0114] To ensure that the impact weight 30 falls accurately vertically onto the anvil face, the vertical guide structure 40 includes roller assemblies 41, 42 mounted on the outer housing 50. Each roller assembly 41, 42 includes horizontal axis rollers 43, here two per assembly, that engage the outer periphery of a tubular impact weight, here.

[0115] These assemblies 41, 42 are configured to preload one or more rollers 43 against the tubular impact weight 30. This is accomplished by a biasing assembly 44 within each roller assembly.

[0116] The roller 43 is shown to have an outer lining of resilient material which engages the outside of the steel impact weight 30 .

[0117] As shown most clearly in FIG. 1A, the driving head assembly 20 includes a resilient material cushion member 23, here an annular resilient material cushion member, which is positioned between the anvil face and the contact surface.

[0118] The driving head assembly 20 is shown to be comprised of a metal ring member 24, the bottom side of which defines a contact surface 21. The metal ring member 24 has an open-topped groove formed therein, and an annular cushion member 23 is received in the groove.

[0119] The anvil surface 22 is shown formed by a metal anvil ring that rests on an annular cushion member 23 .

[0120] Cushion member 23 is shown to have a thickness approximately the same as the thickness of impact weight 30 and a height that is at least the thickness of member 23 .

[0121] For example, the annular cushion member 23 is provided with a cooling system, such as by using water spray, liquid cooling ducts within the head end assembly, or the like.

[0122] For example, the cushion member 23 may be constructed from a laminate of metal and synthetic material, where the metal, for example, facilitates the removal of heat from the cushion member 23 .

[0123] For example, the cushioning member 23 may be constructed of metal elements, eg, fibers, embedded in a synthetic material, where the metal elements facilitate the removal of heat from the cushioning member 23 .

[0124] For example, as shown, the annular cushion member 23 has vertical sides that are higher than the thickness of the cushion member, which facilitates heat dissipation from the cushion member.

[0125] Heat dissipation from the cushion member may help extend the operating life of member 23.

[0126] The piling device 10 is shown to include a sleeve 80 that extends from the head end assembly 20 down along the top section 1 a of the piling 1 .

[0127] As shown, the entire piling device 10 is embodied in such a way that access to the inside of the monopile 1 is possible even during piling. A central passage 90 extends effectively from the top through the bottom end of the device 10 and has a diameter of at least 2 meters, more preferably at least 50% of the diameter of the pile 1, more preferably at least 75%.

[0128] For example, as shown, the passage 90 has a diameter that corresponds at least to the diameter of the opening defined by the inward flange 1b of the pile.

[0129] Preferably, the flange 1b is accessible through this passage 90.

[0130] The large cross-sectional area of ​​the central passage 90, here more than 75% of the diameter of the monopile, allows for the use of other equipment during the pile driving operation, for example, a jetting system which directs a significant high pressure jet line through the passage 90 into the inside of the monopile 1. The housing 50 can be configured to support such additional equipment. Also, in an embodiment, the flange 1b can be used to support additional equipment involved in the pile driving, such as jetting equipment, vibrating equipment, etc.

[0131] This large passageway 90 is also beneficial when the pile driving rig 10 is stored, for example, on the deck of a ship, for example, by allowing a hydraulic power unit associated with the pile driving rig 10 to be located inside the passageway 90 in the stored state.

[0132] As shown most clearly in Figure 7, the piling rig 1 can be configured to be connected to a lifting tool of a crane during piling. Shock absorbers 90 are mounted on top of the piling rig, here on its outer housing 50, and these shock absorbers are connected to a spreader structure 100, here two shock absorbers connecting to a spreader bar at their top ends. The spreader structure is connected to a lifting tool, e.g., a crane hook, here via two slings 101.

[0133] Different versions of the piling device and method of the present invention will be discussed with reference to Figures 8 and 9. In this specification, components corresponding to those shown in Figures 1 to 7 are given the same reference numerals.

[0134] 8 shows a head end assembly 20'. This assembly 20' has a plurality of cylinder units 200 arranged in a circular array on the driving head assembly 20'. For example, there may be between 20 and 60 cylinder units 200 in the assembly 20'. For an 8-meter diameter piling rig as shown, the number may be approximately 40.

[0135] The cylinder device 200 is disposed between an annular anvil member 210 that defines the anvil surface 22 and a bottom member 215 that defines the contact surface 21 .

[0136] Each cylinder device has a cylinder body 201, here all integrated in a steel annular head end body 202 that forms all of the cylinder bodies. Each cylinder device 200 has a single-acting piston and piston rod assembly 203 and chambers 204 separated by the piston. All chambers 204 are completely filled with a liquid, e.g., water in this example. The amount of liquid is preferably adjustable. In one embodiment, all chambers 204 are interconnected.

[0137] For example, each piston of device 200 has a diameter between 20 centimeters and 50 centimeters.

[0138] A multiple cylinder arrangement 200 having a chamber filled with a liquid, e.g., water, effectively acts as a spring to force the impact weight 30 against the anvil face 22. Here, the liquid pressure can rise to very high values, e.g., above 400 bar, e.g., up to about 600 bar.

[0139] In one embodiment, shown schematically in Figure 8b, the cylinder device includes a cylinder body 203b, a piston 203a, and a single chamber 203c bounded by the cylinder body 203b and the piston 203a. The chamber 203c is filled with a liquid, for example oil.

[0140] Piston 203a is embodied as a hollow piston having a central cavity extending from an opening at the bottom end of the piston and bounded by a downwardly extending annular piston wall 203d, the central cavity forming part of a single chamber.

[0141] The bottom end of the piston wall 203d is preferably chamfered.

[0142] A resilient element 203e, for example a solid compressible material element and / or a metallic resilient element, is disposed on the top end of the piston 203a.

[0143] In one embodiment, considering the extremely large maximum pressures that can occur within chamber 204, leakage of liquid along the piston and piston rod assembly can be tolerated instead of attempting to prevent leakage with complex sealing structures. It is envisioned here that a liquid replenishment circuit, e.g., water, is provided to chamber 204, which supplies liquid to chamber 204 to compensate for leakage. For example, leakage of the order of one liter per chamber 204 per stroke is envisioned. Leakage is not an issue from an environmental standpoint, particularly when the liquid is water. If the liquid is oil, which is preferred due to its resilience, any leaked oil should be recovered, e.g., via one or more channels, and supplied to the replenishment circuit.

[0144] In one embodiment, there is no annular anvil member 210, and the entire piston top forms the annular anvil surface onto which the steel impact weight 30 falls.

[0145] In one embodiment, the cylinder devices 200 are disposed at the lower end of the impact weight 30, and preferably each device 200 has its piston extending downward. Here, for example, the impact weight 30 may be embodied as a single tubular ring segment, or the impact weight 30 may include multiple ring segments 32, with one or more cylinder devices 200 disposed at the lower end of each ring segment 32.

[0146] Figure 7 also shows that the outer housing 50 is mounted on top of the head end assembly 20', and therefore essentially on a part that is integral with or formed by the annular anvil member 210.

[0147] The sleeve 80 extends downward from the outer housing 50 , around the head end assembly 20 ′ and down along the upper portion 1 a of the monopile 1 .

[0148] When the impact weight 30 impacts, the head end assembly 20' transfers the impact to the cylindrical wall at the top of the monopile with some spring action. As shown, in the illustrated embodiment, the contact surface 22 is positioned vertically above this wall so that energy is transferred vertically from the impact weight 30 to this cylindrical wall without excessively loading the flange 1b.

[0149] In an embodiment, the system further includes a vibration device 300, as shown in FIG.

[0150] FIG. 10 shows that the vibrating device 300 is independently suspended and not mechanically attached to the driving device 10 .

[0151] Preferably, the passageway 90 is sized so that the device 300 can be moved through the passageway 90, eg, removed without having to remove the device 10 from the pile 1.

[0152] Preferably, the vibratory device has a clamping mechanism operable to clamp the device 300 to the pile 1 , for example a hydraulically actuated clamp 306 that frictionally fits inside the pile 1 .

[0153] One or more rotating eccentric mass units 307 induce the desired vibrations as known in the art.

[0154] The vibrating device 300 is mechanically isolated from the pile driving device 10 and can be selectively disconnected from the pile 1, so that the vibrating device 300 is not subjected to, or is subjected to, limited impacts caused by the impact weight 30.

[0155] FIG. 10 shows how the vibrating device 300 is suspended from a crane, here via a cable 301, e.g. the same crane from which the piling device is suspended, e.g. via the aforementioned shock absorber 90 and possibly a spreader structure 100.

[0156] Optionally, the vibration device 300 is suspended from the spreader structure 100, for example via a winch device.

[0157] For example, the vibration device 300 is configured to vibrate the pile about its vertical axis and generate an alternating force about the axis at a vibration frequency to reduce friction between the pile and the soil, e.g., the seabed.

[0158] For example, the vibration device 300 is configured to generate vertical vibrations to drive the pile into the soil, which in embodiments can be combined with vibration of the pile about a vertical axis to reduce friction between the pile and the soil, e.g., the seabed.

[0159] The central passage of the driving rig also provides access to the vibrating rig, for example in terms of energy supply to the vibrating rig, for example for hydraulic lines supplying hydraulic oil to the motor of the vibrating rig.

[0160] For example, the vibrating device 300 is only connected to the pile 1 when the pile driver 10 is not impacting the pile, thereby avoiding excessive mechanical loads on the vibrating device.

[0161] For example, the vibrating device 300 is used in a first stage of driving the pile into the soil, and the pile driver 10 with the impact weight 30 is used in a second stage of driving the pile 1 into the soil. This can, for example, reduce the overall noise generation of the (mono)pile installation.

[0162] 11a shows a longitudinal cross section of one embodiment of the impact weight 30, which includes five ring members 30a-30e that are stacked on top of one another to form the impact weight 30. Each ring member 30a-30e includes multiple ring segments 32. The ring segments are not vertically aligned such that the ring segments 32 of adjacent ring members 30a-30e overlap adjacent ring segments in at least two vertical directions. Vertical fasteners 33, such as bolts, are used to connect adjacent ring members and adjacent ring segments to one another.

[0163] Figure 11b shows a cross section of impact weight 30, with each ring segment 32 being semicircular, such that the ring members 32 form the ring members of the tubular impact weight. Each ring segment has multiple, here three, holes 34. When the ring members are stacked on top of each other, the holes 34 line up, allowing vertical fasteners 33 to be inserted through the aligned holes. For example, fasteners 33 may be long bolts.

[0164] 11c shows an alternative embodiment of the impact weight 30, which includes three ring segments 32 connected to one another using elastic or spring zones 35 that bridge the small distance between adjacent ring segments 32. For example, the elastic zones 35 may be embodied as steel parts, e.g., welded parts, with, e.g., folded sections, an example of which is shown here. While each elastic zone 35 is shown with an inwardly folded section, other configurations are possible.

[0165] FIG. 11d shows an alternative embodiment of an impact weight 30, which includes multiple segments 32. The ring segments have inner and outer wall surfaces and a wall thickness. Adjacent ring segments are connected to one another by welds, here vertical welds. The welds extend from alternating inner and outer wall surfaces. Each weld does not extend through the wall thickness of a ring segment, but rather extends only partially between the inner and outer wall surfaces. This results in alternating vertical grooves. As explained, this alternating arrangement of partial welds reduces tangential peak stresses in the impact weight.

[0166] FIG. 11e shows an alternative embodiment of the impact weight 30, in which the impact weight is provided with evenly distributed axial slots 37, which are spaced tangentially.

[0167] 11f shows one embodiment of the impact weight 30, which includes 16 ring segments 32, each embodied as a quadrilateral segment, such that the connected ring segments 32 form a 16-sided polygon. Here, the ring segments are welded together, although other arrangements are possible (as discussed herein). The 16-sided polygonal cross-section can be considered an approximation to a circular design. In another embodiment, a polygonal cross-section with, for example, 32 sides is also practical, taking into account the diameter of the weight 30.

[0168] FIG. 11g shows a cross section of an alternative embodiment of the impact weight 30, which includes holes 38 extending from the bottom of the impact weight 30 along the height of the impact weight, the holes being distributed around the circumference of the impact weight 30. The length of the holes is between 50% and 90% of the height of the impact weight, preferably between 60% and 80% of the height of the impact weight. An elongated member 39, e.g., a solid steel rod, is received inside the hole and extends along its entire length, with the lower end of the elongated member 39 extending beyond the bottom of the impact weight and contacting the anvil face. It is envisioned that the elongated members 39 act as axial springs with radial play, e.g., within their respective holes. In an embodiment, as shown, each elongated member 39 can have a leg configured to contact the anvil face.

[0169] Figure 12a shows a pile run prevention member 400 including a damping member 401 suspended from a pile driver, or optionally a crane. An engagement member 402 is suspended from the damping member 401 and engages the inward facing top flange 1b of the pile 1.

[0170] 12b shows an alternative embodiment of a pile run prevention member 400, which is embodied as a cable 403 having a first end and a second end, the first end hanging from the pile driver and the second end carrying an engagement member 402 configured to engage an inwardly facing top flange 1b of the pile. As shown, the cable 403 is slack during pile driving. [Explanation of symbols]

[0171] 1 Monopile 1a Top section, top wall, upper part 1b flange 10 Pile driving equipment 20 Driving head assembly 20' Driving Head Assembly 21 Contact surface 22 Anvil Surface 23 Cushion member 30 Impact weight 30a~30e Ring members 31 holes 32 ring segments 33 Vertical fasteners 34 holes 35 Elastic Zones 37 slots 38 holes 39 Slender members 40 Vertical guide structure 41, 42 Roller assembly 43 Horizontal axis roller 44 Actuation assembly 50 Housing 51 Inward Top Flange 61 Integrated lift accelerator 62 Piston rod 63 Cylinder body 64 Lower Chamber 65 Upper Chamber 66 Gas Buffer 67 Common duct equipment 68 Hydraulic Pump 70 Quick Release System 80 sleeve 90 Passage, shock absorber 100 Spreader Structure 101 Sling 200 Cylinder device 201 Cylinder body 202 Steel annular head end body 203 Piston rod assembly 203a Piston 203b Cylinder body 203c Chamber 203d Piston wall 203e Elastic Elements 204 Chamber 210 Annular anvil member 215 Bottom member 300 Vibration device 301 Cable 306 Hydraulically Actuated Clamp 307 Rotating Eccentric Mass Unit 400 Pile run prevention member 401 Damping member 402 Engagement member 403 Cable

Claims

1. A pile driving method for vertically driving a hollow, open-ended, large-diameter steel pile into the ground, wherein the large-diameter steel pile has a cylindrical top having a top wall thickness between its inner and outer diameters, and the outer diameter is at least 5 meters. A pile driving device is used, which is positioned at the top of the aforementioned large-diameter steel pile. A driving head assembly having an annular contact surface placed on the top end of the large-diameter steel pile, and an annular anvil surface above the annular contact surface, A steel impact weight having a mass of at least 100 tons, the impact weight being vertically movable above the annular anvil surface of the driving head assembly, A vertical guide structure configured to guide the impact weight vertically, wherein the driving head assembly is configured to transfer energy between the annular anvil surface and the annular contact surface in order to transfer energy from the falling impact weight to the annular contact surface and, consequently, to the top of the large-diameter steel pile, A lift system configured to bring the impact weight to the initial height position relative to the annular anvil surface of the driving head assembly, A quick-release system adapted to quickly release the lift system so that the impact weight falls from the initial height position onto the annular anvil surface of the driving head assembly, Includes, The aforementioned method, The impact weight is lifted to the initial height position by the lift system. The quick-release mechanism operates to perform the quick-release of the lift system so that the impact weight falls from the initial height position onto the annular anvil surface of the driving head assembly, and the energy from the falling impact weight is transmitted to the annular contact surface of the driving head assembly and, consequently, to the top of the large-diameter steel pile, causing the large-diameter steel pile to be driven deeper into the ground. Includes repeating cycles, The aforementioned impact weight is embodied as a tubular impact weight made of steel. Pile driving method.

2. The pile driving method according to claim 1, wherein the tubular impact weight has a height between 4 meters and 12 meters.

3. The pile driving method according to claim 1 or 2, wherein the tubular impact weight has a diameter such that, when projected vertically, the tubular impact weight overlaps with the thickness of the top wall of the top of the large-diameter steel pile.

4. The pile driving method according to claim 1, wherein the pile driving device is provided with a plurality of acceleration devices, the acceleration devices are arranged in a circular array and engage with the tubular impact weight at distributed positions.

5. The pile driving method according to claim 1, wherein the pile driving device is configured such that the tubular impact weight falls only under gravity (1G).

6. The pile driving method according to claim 1, wherein the tubular impact weight is hollow and has an open end, and the tubular impact weight has a central passage with a diameter of at least 2 meters.

7. The pile driving method according to claim 1, wherein the large-diameter steel pile has an inward-facing top flange, and the driving head assembly is configured to expose a portion of the inward-facing top flange so that the inward-facing top flange can be gripped by a gripper of a pile lifting tool.

8. The pile driving method according to claim 1, wherein the tubular impact weight has a wall thickness between 10 centimeters and 20 centimeters.

9. The pile driving method according to claim 1, wherein the lifting means is configured such that the vertical distance between the annular anvil surface and the initial height of the impact weight is at most 2 meters.

10. The pile driving method according to claim 1, wherein the pile driving device has an outer housing that extends coaxially around the tubular impact weight, the outer housing has an open lower end that rests on the driving head assembly, and the outer housing has a closed periphery.

11. The pile driving method according to claim 1, wherein the lift mechanism includes a plurality of hydraulic lift cylinders, and the quick-release system includes one or more quick-release valves that open to allow rapid discharge of hydraulic fluid from the hydraulic lift cylinders.

12. The pile driving method according to claim 1, wherein the vertical guide structure includes a roller assembly, each roller assembly includes one or more horizontal axis rollers that engage with the tubular impact weight, and the roller assembly is configured to preload and press the one or more horizontal axis rollers against the tubular impact weight.

13. The pile driving method according to claim 1, wherein the pile driving device is connected to a lifting tool of a crane during pile driving, a plurality of shock absorbers are mounted on the top of the pile driving device, the plurality of shock absorbers are connected to a spreader structure at the top ends of the shock absorbers, and the spreader structure is connected to the lifting tool.

14. The pile driving method according to claim 1, wherein the method is performed at sea for the installation of a monopile, and a vessel is used which includes a pile gripping device that operates to hold the large-diameter steel pile vertically during pile driving.

15. A pile driving system for vertically driving a hollow, open-ended, large-diameter steel pile into the ground, wherein the large-diameter steel pile has a cylindrical top having a top wall thickness between its inner and outer diameters, and the outer diameter is at least 5 meters. The pile driving system includes a pile driving device configured to be positioned at the top of the large-diameter steel pile, and the pile driving device is A driving head assembly having an annular contact surface configured to be placed on the top end of the large-diameter steel pile, and an annular anvil surface above the annular contact surface, A steel impact weight having a mass of at least 100 tons, the impact weight being vertically movable above the annular anvil surface of the driving head assembly, A vertical guide structure configured to guide the impact weight vertically, wherein the driving head assembly is configured to transfer energy between the annular anvil surface and the annular contact surface in order to transfer energy from the falling impact weight to the annular contact surface and, consequently, to the top of the large-diameter steel pile, A lift system configured to bring the impact weight to the initial height position relative to the annular anvil surface of the driving head assembly, A quick-release system adapted to quickly release the lift system so that the impact weight falls from the initial height position onto the annular anvil surface of the driving head assembly, Includes, The aforementioned pile driving device, The impact weight is lifted to the initial height position by the lift system. The quick-release mechanism operates to quickly release the lift system so that the impact weight falls from the initial height position onto the annular anvil surface of the driving head assembly, and the energy from the falling impact weight is transmitted to the annular contact surface of the driving head assembly and, consequently, to the top of the large-diameter steel pile, causing the large-diameter steel pile to be driven deeper into the ground. It can operate in a repeating cycle, The aforementioned impact weight is embodied as a tubular impact weight made of steel in this pile-driving system.

16. The pile driving system according to claim 15, wherein the impact weight has a height between 4 meters and 12 meters.

17. The pile driving system according to claim 15, wherein the pile driving device is provided with a plurality of acceleration devices, the plurality of acceleration devices are arranged in a circular array and engage with the tubular impact weight at distributed positions.

18. The pile driving system according to claim 15, wherein the pile driving device is configured such that the tubular impact weight falls only under gravity (1G), and the pile driving device does not have one or more accelerators for the impact weight.

19. The pile driving system according to claim 15, wherein the tubular impact weight has a diameter such that, when projected vertically, the tubular impact weight overlaps with the thickness of the top wall of the top of the large-diameter steel pile.

20. The pile driving system according to claim 15, wherein the tubular impact weight has a central passage with a diameter of at least 2 meters.

21. The pile driving system according to claim 15, wherein the pile driving device has an outer housing extending coaxially around the tubular impact weight, the outer housing having an open lower end that rests on the driving head assembly, the outer housing having a closed periphery, the outer housing having an open top end, and having a central passage with a diameter corresponding to at least 50% of the inner diameter of the top of the large-diameter steel pile.

22. The pile driving system according to claim 15, wherein the lift mechanism includes a plurality of hydraulic lift cylinders, and the quick-release system includes one or more quick-release valves that open to allow rapid discharge of hydraulic fluid from the hydraulic lift cylinders.

23. The pile driving system according to claim 15, wherein the vertical guide structure includes a roller assembly, each roller assembly includes one or more horizontal axis rollers that engage with the tubular impact weight, and the roller assembly is configured to preload and press the one or more horizontal axis rollers against the tubular impact weight.

24. The pile driving system according to claim 15, wherein the energy transfer assembly of the driving head assembly includes one or more spring devices and / or one or more damper devices that are effective between the annular anvil surface and the annular contact surface.

25. The pile driving system according to claim 15, wherein the driving head assembly includes a plurality of spring devices and / or a plurality of damper devices arranged in a circular array on the driving head assembly.

26. The pile driving system according to claim 15, wherein the driving head assembly includes a plurality of cylinder devices arranged in a circular array on the driving head assembly, each of the plurality of cylinder devices having a cylinder body, a piston, and a chamber separated by the piston, the chamber being filled with liquid.

27. The pile driving system according to claim 15, wherein the pile driving device includes a sleeve extending downward from the head end assembly along the top section of the large-diameter steel pile.

28. The pile driving system according to claim 15, further comprising a vibrator.

29. The pile driving system according to claim 28, wherein the vibrating device is configured to vibrate the large-diameter steel pile around its vertical axis and generate alternating forces around the vertical axis at a vibration frequency in order to reduce friction between the large-diameter steel pile and the soil.

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