Method and system for driving a pile

Abstract

This invention discloses a method for driving an offshore pile (1) into soil (S) (i.e., pile driving). The method includes: providing a pile (1) including a peripheral wall (11) extending from a lower open end (12); positioning the pile (1) in a first position, wherein the lower open end (12) of the peripheral wall (11) is closed by the soil (S) to define an internal space (13) inside the peripheral wall (11); providing a coaxially configured pile drive assembly at or in one of the upper ends (15) of the pile (1); and providing a position adjacent to the pile (1). A pumping device (2) is installed; a driving force (F) is applied to the pile (1) using the pile drive assembly to drive the pile (1) into the soil (S); and during the application of the driving force (F), water is pumped from the interior space (13) using the pumping device (2) to lower the water level (Wi) in the interior space (13) so that water flows from the outside of the pile (1) through the lower open end (12) of the peripheral wall (11) into the interior space (13).

Description

Technical Field

[0001] This invention generally relates to offshore piles. More specifically, but not exclusively, this invention relates to a method for driving a pile into the soil. Prior Technology

[0002] Offshore piles (such as foundation piles, such as monopiles or casing piles) are driven into the soil to provide a foundation for the structure above water.

[0003] Piles are typically driven into the seabed using an axial force. This axial force can take the form of sequential axial impacts or pulses provided by a pile-driving tool (e.g., a pile-driving hammer). Alternatively, it can be a vibratory axial force applied to the pile. Clearly, driving the pile with an axial force requires sufficient energy to be transmitted to the pile to overcome the resistance supplied by the soil. This resistance includes the direct force acting on the pile tip or lower edge, as well as frictional forces acting on the inner and outer radial surfaces of the pile.

[0004] To overcome the direct forces acting on the pile tip, the pile must displace seabed material away from the path of the pile tip as it is driven into the soil. The pile diameter can be between, for example, 6 m and 13 m, and the wall thickness can be, for example, 100 mm. Therefore, the surface area of ​​the pile tip can be up to, for example, 4 m². Consequently, to move the pile 250 mm into the soil, up to 1 m³ of soil may need to be displaced, which requires a significant amount of energy. Furthermore, as the pile moves deeper, the soil becomes denser, and the resistance provided by the soil to the pile tip increases, thus requiring an additional amount of energy to be supplied to the pile.

[0005] It should be understood that the frictional force acting on the radial surface of the pile also increases with depth, because more surface becomes in contact with the soil. In addition, as the pile penetrates deeper into the soil, the direct force acting on the radial surface increases due to the denser soil, thereby increasing the frictional force.

[0006] Overcoming these resistances requires applying very large axial forces to the pile. These axial forces generate large stress fluctuations within the pile, which can sometimes lead to damage or even fracture of the pile or associated structures. Damage may be fatigue damage, affecting the pile's residual fatigue capacity, which in turn affects the lifespan of the pile and associated structures. Therefore, piles must be designed with sufficient strength to withstand high impact forces, increasing their cost. For example, this may involve controlling the wall thickness of the pile to drive the load. Furthermore, vibrations of the pile caused by impacts transmitted through an installation tool generate significant noise during the piling process, resulting in negative environmental effects and increasing health risks to nearby personnel.

[0007] It is known that suction caissons are used as anchors or supports. Suction caissons are typically tubular in shape, with one closed end and one open end. The open end is placed on the soil and is allowed to penetrate the soil due to the caisson's own weight. Water is then pumped through the closed end, creating a lower pressure inside the caisson relative to the outside, causing the caisson to penetrate the soil further. The penetration depth is much smaller due to the lower force applied compared to pile-driven methods. Therefore, due to the lower penetration depth, suction caissons provide a lower overturning moment resistance than driven piles of the same diameter, because the driven piles are installed deeper.

[0008] It is also known that when the pile tip is driven into the soil, a water jet positioned at the pile tip is used to remove material from the path of the pile tip. This reduces the effective stress in the soil near the pile tip as the pile is driven into the soil, making it easier for the pile tip to displace soil particles. An example of this procedure is provided in WO2019 / 206690. In WO2019 / 206690, the pile tip is angled inward relative to the pile to guide the soil toward an inner bore of the pile as the pile is pushed into the soil. The jet also removes material in an inward and downward direction, and a pump removes water and soil material from the inner bore of the pile. Obviously, providing such jets increases the cost and complexity of the piling procedure. In addition, a control system is needed to minimize the pressure difference between the soil near the pile tip and the surrounding water to prevent the soil material outside the pile from being weakened. Summary of the Invention

[0009] One object of the present invention is to overcome at least some of these limitations.

[0010] As will be understood, overcoming the above limitations will enable the use of piles with larger diameters. Alternatively, overcoming the above limitations will allow piles of the same size to be driven into the soil with less force, thereby allowing the use of simpler and / or smaller vessels and installation equipment to install the piles.

[0011] According to a first aspect of the present invention, a method is provided for driving an offshore pile (e.g., an offshore foundation pile) into soil (e.g., soil of an underwater seabed), the method comprising: Provide a pile, the pile including a peripheral wall extending from one of its open ends; The pile is positioned at a first location, wherein the lower open end of the perimeter wall is closed by the soil to define an interior space inside the perimeter wall; A pile drive assembly with a coaxial configuration is installed at the upper end or middle of one of the piles; A pumping device was installed at a location adjacent to the pile. Using the pile drive assembly, a driving force is applied to the pile to drive it into the soil; and During the application of the driving force, water is pumped from the interior space using the pumping equipment to lower the water level in the interior space, so that water flows from the outside of the pile through the lower open end of the peripheral wall into the interior space.

[0012] Advantageously, generating a water flow reduces the effective stress between soil particles near the lower end of the perimeter wall, thereby reducing the resistance provided by the soil to the movement of the perimeter wall into the soil. Reducing the water column height inside the pile also advantageously reduces the pressure on the soil inside the pile, and thus reduces the stress between soil particles in the soil inside the perimeter wall, making it easier for soil particles to displace at the lower edge of the perimeter wall. As the pile moves downward into the soil, reducing the water column height inside the pile also reduces the hydrodynamic resistance caused by water thrust acting on the radially inner surface of the perimeter wall. All these factors reduce the necessary amount of the driving force applied, thereby reducing the size, complexity, and cost of the pile drive equipment and vessel. By reducing the necessary load applied to the pile, noise generated during pile drive is reduced, and stress applied to the pile is reduced. Therefore, the risk of damage to the pile, or the degree of fatigue, is reduced. Furthermore, lower load requirements necessitate flexibility in pile design, such as using larger diameter piles with reduced wall thickness, or incorporating non-perpendicular or truncated conical sections with a larger angle relative to the pile's axis.

[0013] Advantageously, water is pumped out while driving force is applied. This helps reduce resistance from the soil, which acts against movement into the soil from the open end below the perimeter wall.

[0014] Pumping water from the internal space can lower the water level within the internal space to below a level outside the pile. Advantageously, this results in a reduction in the hydrostatic pressure within the internal space. This pressure reduction promotes water flow from the outside of the pile into the internal space. Advantageously, the pressure reduction within the internal space also allows the pile to withstand the hydrostatic pressure of the surrounding water.

[0015] The method may further include: A sensor is provided, wherein the sensor is disposed in the interior space. The sensor is used to measure either the pressure within the interior space or the water level within the interior space. The pumping parameters of the pumping equipment are determined based on measurements from this sensor. For example, a control system is used to operate the pumping equipment with the determined pumping parameters.

[0016] The pile can be a single pile or a set of pipe piles.

[0017] During the application of the driving force, water can be pumped from the interior space, causing the water to flow through the soil adjacent to the lower edge of the perimeter wall or the tip of the pile.

[0018] Advantageously, the effective stress between soil particles near the lower edge will be reduced, thereby reducing the resistance provided by the soil to the lower edge when the perimeter wall is driven into the soil.

[0019] During the application of the driving force, water can be pumped from the interior space, causing the water to flow through the soil adjacent to one of the radial outer surfaces or one radial inner surface (or both of the radial outer and radial inner surfaces) of the peripheral wall.

[0020] When the pile is driven into the soil, a water flow is generated near the radial inner wall and near the radial outer wall, which in turn reduces the friction between the respective walls and the soil.

[0021] Water flow from the outside of the pile to the interior space may include water flowing through at least one channel located in one of the radially outer surfaces of the peripheral wall.

[0022] The at least one channel may extend from the lower end of the peripheral wall to a position above the soil when the pile is in the embedded position. The at least one channel may extend circumferentially around the peripheral wall. The at least one channel may cut into the peripheral wall.

[0023] Advantageously, channels are provided in the radially outer surface of the perimeter wall to facilitate fluid flow through the soil adjacent to the radially outer wall, thereby preventing an increase in effective stress between soil particles on the outer side of the perimeter wall. Furthermore, if the soil is otherwise substantially sealed against the radially outer surface, these channels can initiate fluid flow from the outside of the pile to the interior space.

[0024] Water can be pumped out of the internal space through one of the openings in the pile. This opening may be located at the upper end of one of the piles. The opening may extend through the peripheral wall. Advantageously, providing this opening through the peripheral wall means that pumping does not obstruct the pile drive assembly. The opening may be a via, through which a cable is passed once the pile is in operation. Advantageously, using a cable hole to pump water out of the pile means that no structural modifications to the pile are required for pumping.

[0025] The pile drive assembly may include a hammer or a weight that raises and lowers the pile, thereby transferring energy to the pile. The weight may be water stored in a tank.

[0026] The pile or pile drive assembly may further include a closing member. This closing member closes an open end on one of the peripheral walls. Water can be pumped out of the internal space through an opening in the closing member. Advantageously, when the pressure in the internal space decreases during pumping, the hydrostatic pressure from the surrounding water can act on the closing member to push the pile into the soil. Furthermore, the closing member defines a closed or substantially sealed space within the internal space. Thus, in the event of encountering a soft soil layer during pile drive, the pile will descend and rapidly penetrate the soil, and the pressure in the internal space will increase due to the rapid contraction of the internal space. This increase in pressure will prevent the pile from descending further into the soil or at least reduce the risk.

[0027] The pile drive assembly can apply a regular axial load. This regular axial load can include predetermined sequential impacts. This regular axial load can also include vibration loads.

[0028] When the pile is positioned in the first location, a pile holder can be used to hold the pile in a vertical orientation.

[0029] The step of positioning the pile at the first location may include lowering the pile onto the soil to the first location. This can be done using a crane. The weight of the pile may cause the perimeter wall to penetrate the soil.

[0030] At this embedding location, the lower edge of the peripheral wall may be between 20 m and 50 m below the surface of the seabed.

[0031] Once the pile is driven into the soil to a predetermined depth, it can be configured to support an overwater structure, which may be a wind turbine.

[0032] It can seal all underwater openings in the pile, further including the open end of the peripheral wall closed by the soil, and further including any opening through which water is pumped.

[0033] The pile may include a lower section having a first diameter. The pile may include an upper section. The upper section may have a second diameter. The second diameter may be smaller than the first diameter. The upper section may be truncated conical or tapered. Applying a driving force to the pile to drive it into the soil may involve driving a portion of the lower section of the pile into the soil.

[0034] The method may further include connecting the upper section to the lower section after the lower section has been driven into the soil. Advantageously, the upper section may not be subjected to driving force. Therefore, a lighter and / or less complex upper section can be used compared to a case where the upper section is subjected to driving force. This allows for the use of less complex and / or less expensive pile driving devices. By using lighter materials, a smaller installation vessel can also be used, thereby further reducing complexity and cost. Further advantageously, the entire pile can be decommissioned by removing any structure above the lower section and then pressurizing the water below the pressure vessel head and inside the lower section by applying a pressure vessel head to the lower section, thereby pushing the lower section out of the soil.

[0035] The pile may further include an intermediate section located between the lower section and the upper section. The intermediate section may be truncated conical in shape.

[0036] Advantageously, the reduction of the water column within the internal space reduces the hydrostatic resistance on the radially inner surface of the peripheral wall, which is particularly pronounced in non-vertical sections (e.g., intermediate sections). That is, previously, when the pile was driven downwards, the gradual decrease in the diameter of the intermediate section accelerated the water upwards, thereby significantly increasing the hydrostatic resistance on the radially inner surface of the intermediate section. Further advantageously, the reduction in the column height on the inner side of the pile relative to the outer water level increases the hydrostatic pressure on the intermediate section, which is used to push the pile into the soil.

[0037] According to a second embodiment of the present invention, a system for driving an offshore pile into the soil is provided, the system comprising: A pile, which includes a peripheral wall extending from one open end; A positioning device for positioning the pile in a first position, wherein the lower open end of the peripheral wall is closed by the soil to define an interior space inside the peripheral wall; A pile drive assembly for applying a driving force to the pile to drive the pile into the soil, wherein, in use, the pile drive assembly is coaxially configured at or in the upper end of one of the piles; and A pumping device is used to pump water from the interior space during the application of the driving force to lower the water level in the interior space, so that water flows from the outside of the pile through the open end below the peripheral wall into the interior space.

[0038] The system of the second state of the present invention can be used to implement the method of the first state of the present invention.

[0039] The system may further include a sensor. This sensor can be configured to measure pressure or water level in the internal space. Measurements from the sensor can be used to control the pumping equipment. That is, a control system can use the sensor measurements to determine the appropriate operation of the pumping equipment. Measurements from the sensor can be used to control the pile drive assembly to control the magnitude of the driving force applied to the pile. Measurements from the sensor can be used to detect pile descent and rapid penetration of the soil caused by an increase in pressure in the internal space. Detection of pile descent can be used to control the pile drive assembly to reduce the magnitude of the driving force applied to the pile. Measurements from the sensor can be used to determine a pressure difference between the internal space and the outside of the pile. This pressure difference can be used to calculate a downward force acting on the pile due to the pressure difference. The downward force due to the pressure difference can be used to control the pile drive assembly to control the magnitude of the driving force varying according to the downward force due to the pressure difference.

[0040] The system may include a closure component. The closure component may be configured to close an open end on one of the peripheral walls.

[0041] The system may further include a pile holder. When the pile is positioned in the first location, the pile holder can be used to hold the pile in a vertical orientation.

[0042] The pile may include a lower section having a first diameter and an upper section having a second diameter. The second diameter may be smaller than the first diameter. In use, applying a driving force to the pile to drive it into the soil may involve driving a portion of the lower section of the pile into the soil.

[0043] The pile may further include an intermediate section located between the lower section and the upper section. The intermediate section may be truncated conical in shape.

[0044] The pumping device can be positioned outside the pile. Advantageously, this means that holes (such as cable entry holes) existing in the peripheral wall can be used to pump water from the interior space. Therefore, the pump guide tube does not need to travel through the upper end of the pile, where it could interfere with the pile drive assembly. Furthermore, since the holes (such as cable entry holes) already exist in the peripheral wall, no alteration to the pile is required to pump the water out of the interior space. Further advantageously, by positioning the pump outside the pile, the pump does not obstruct the pile drive assembly.

[0045] The system may further include a crane for lowering the pile into the soil in a first position. The system may further include a floating platform to which the pile is suspended before being driven into the soil. Simple Explanation of the Diagram

[0046] The installation method and corresponding system will now be described with reference to the accompanying drawings, using only examples: Figure 1 is a schematic diagram of one method for driving an offshore pile into the soil; Figure 2 is a schematic diagram of one method for driving offshore piles into the soil using a second method; Figure 3 is a schematic diagram of one of the different offshore pile designs being driven into the soil; and Figure 4 is a schematic diagram of another different offshore pile design being driven into the soil. Implementation

[0047] Turning to Figure 1, a first example of a method for installing a pile 1 into soil S is shown. In this example, pile 1 is a monopile, but it should be understood that the method disclosed herein can be applied to other piles, such as casing piles. Pile 1 has a peripheral wall 11 extending from a lower open end 12. In this example, the peripheral wall 11 has a lower section 11a and an upper section 11b. The lower section 11a is cylindrical in shape. The upper section 11b is truncated conical in shape. A lower end of the upper section 11b has a diameter equal to that of the lower section 11a. The upper end of the section 11b, which is above the upper end 15 of the pile 1, has a diameter smaller than that of the lower section 11a.

[0048] The pile 1 is driven into the soil S of an underwater seabed. The soil S may have any known soil type suitable for pile driving, such as clay or sand. The length of the lower section 11a is generally greater than one depth into which the pile 1 is driven into the soil S.

[0049] To drive pile 1 into the soil S, pile 1 is positioned in a first position (not shown). In the first position, the open end 12 of pile 1 is closed by the soil S to define an internal space 13 inside the peripheral wall 11.

[0050] In this example, pile 1 is positioned to a first position by lowering it from an installation device (not shown) (e.g., a floating installation vessel). A crane (not shown) is used to lower pile 1. Pile 1 is lowered to the soil S such that the lower end 14 of one of the peripheral walls 11 first reaches the soil S. The weight of pile 1 causes the peripheral wall 11 to penetrate the soil S.

[0051] In this example, a pile holder (not shown) is introduced to stabilize pile 1, keeping it in a vertical orientation. Once pile 1 is stabilized, the crane and associated connecting ropes are removed.

[0052] To drive pile 1 into the soil S, a driving force F is applied to pile 1. In this example, the driving force F is applied to the upper end 15 of pile 1. The driving force F drives pile 1 from a first position to an embedded position (as shown in Figure 1).

[0053] In this example, the driving force F is executed by a pile drive assembly. The pile drive assembly may include a hammer, a vibratory hammer, or a static weight (e.g., a reservoir filled with water). The pile drive assembly may further include components for lifting and subsequently lowering the hammer or weight to transfer energy to the pile. That is, the driving force F may include sequential impact, vibration load, or the like.

[0054] In this example, the pile drive assembly also includes an anvil 3 disposed at the upper end 15 of the pile 1 during the driving force F. The anvil 3 is substantially disc-shaped, and the upper end 15 of the pile 1 engages with a lower surface of the disc-shaped anvil 3. However, it will be understood that any suitable anvil 3 can be used. It will also be understood that the anvil 3 can be omitted, and the driving force F can be applied directly to the peripheral wall 11.

[0055] When a driving force F is applied to pile 1, pile 1 is driven into the soil S. During the application of the driving force F, water is pumped from the internal space 13 to lower the water level Wi in the internal space 13, causing water to flow from the outside of pile 1 through the open end 12 below the peripheral wall 11 into the internal space 13. As water is pumped from the internal space, the water level Wi decreases to below or far below the water level Wo around pile 1. It will be understood that soil S, debris, or marine organisms can also be pumped out of the internal space 13. In this example, water is pumped into the water around pile 1.

[0056] The pumping of water can begin when the perimeter wall 11 reaches a predetermined penetration depth in the soil S. For example, the pumping of water can begin when the pile 1 penetrates the soil only by its own weight, or the pumping of water can only begin when the pile 1 has been driven into the soil through a specific depth.

[0057] In this example, during the application of the driving force F, a pump 2 located outside the pile 1 is used to pump water from the internal space 13. Water is pumped from the internal space 13 at a rate sufficient to lower the water level Wi in the internal space 13, and then at least maintains the lowered water level Wi. This creates a pressure difference between the outer and inner sides of the peripheral wall 11. This pressure difference causes water to flow from the outside of the pile 1 through the soil S into the internal space 13.

[0058] The water level Wi in the internal space can be lowered by any suitable amount. However, it should be understood that the greater the reduction in water level Wi, the greater the pressure difference. For example, the water level Wi can be lowered so that it is approximately or substantially equal to the surface of the seabed (as shown in Figure 1).

[0059] The water flow from the outside of pile 1 to the internal space 13 can take the form of several discrete flow paths, a typical flow path shown by a dashed line in Figure 1. In this flow path, water flows downward from above the soil surface S, adjacent to one of the radially outer surfaces of the peripheral wall 11, around the lower edge 14 of the peripheral wall 11, and into the open end 12 below the peripheral wall 11. Then, the flow continues upward adjacent to one of the radially inner surfaces of the peripheral wall 11.

[0060] Pump 2 is submerged underwater and tethered to a floating structure, or is a floating pump. Pump 2 is fluidly coupled to the internal space 13 via a conduit 21. In this example, conduit 21 is a flexible conduit. The use of a flexible conduit reduces the risk of damage to conduit 21 or pump 2 during operation. In this example, conduit 21 travels through a hole, which, for example, is a cable hole used to pass a cable through the peripheral wall once the pile 1 is in the embedded position. All other holes in the pile 1 underwater are sealed.

[0061] During the driving force F, the pile holder stabilizes pile 1 until pile 1 is fully stabilized by the soil S. At this point, the pile holder can be removed.

[0062] As water is pumped from the internal space 13, the driving force F continues until the pile 1 reaches an embedded position. It should be understood that an embedded position of the pile 1 is at a depth at which it can be effectively used as a foundation, for example, to support a floating structure such as a wind turbine. For example, at the embedded position, the lower edge 14 of the peripheral wall 11 may be between 20 m and 50 m below the surface of the seabed 5.

[0063] Once in the embedded position, the installation equipment including the pile drive assembly, pump 2 and conduit 21 is removed, and the underwater structure is assembled onto the pile 1.

[0064] By generating a fluid flow or fluid channel from the outside of the pile to the internal space 13 during the application of the driving force F, the effective stress between soil particles on the surface of the adjacent peripheral wall 11 is reduced. This reduces the resistance exerted on the pile 1 by the soil S, thereby reducing the amount of energy required to drive the pile 1 into the soil S. Furthermore, by removing or lowering the water level in the internal space 13, the volume of water moving upward within the upper section 11b of the peripheral wall 11 when the pile 1 is driven downward is reduced. The truncated conical shape of the upper section 11b means that if water were to move upward on its inner side (relative to the downward movement of the pile 1), a significant amount of hydrostatic resistance would act on the radially inner surface. Therefore, removing water prevents this hydrostatic resistance from occurring. Furthermore, by removing water from the inner side of the upper section 11b, the hydrostatic pressure exerted on the upper section 11b by the surrounding water will further drive the pile 1 into the soil S. Furthermore, by lowering the internal water level Wi, due to the lower water column exerting less pressure on the soil S, the stress between particles in the soil inside and below the peripheral wall 11 is reduced, and therefore the particles can be more easily displaced from the peripheral wall 11.

[0065] In summary, by pumping water out of the internal space 13, compared to pumping water from a space 13 outside the same pile 1, the driving force F requires less energy to drive the pile 1 into the embedment position. This can reduce the cost and / or complexity of the pile driving method, or may allow larger piles 1 to be driven into the soil S.

[0066] Turning now to Figure 2, a second example of one method for installing a pile 1' into the soil S is shown. This example is similar to the first example (as described with reference to Figure 1), and similar features are indicated by similar element symbols followed by an apostrophe. The method in this example differs from the first example only in that the pump 2' is in the internal space 13' and at least partially submerged in water, except that the pump 2' pumps water out of the internal space 13'. A downstream conduit 22' is also provided, which delivers water from the pump 2' and exits through the upper end 15' of the pile 1'. The downstream conduit 22' may travel through the anvil 3' and any other component of the pile drive assembly, or the pump 2' and conduit 22' may be lowered into the internal space 13' between continuous loads applied to the pile 1' in the driving force F'.

[0067] As shown in the first example method in Figure 1, the second example method shown in Figure 2 extracts water from the internal space 13' to generate a water flow path through the soil S, thereby reducing the effective stress between the soil particles and reducing the resistance from the soil S acting on the peripheral wall 11'.

[0068] The method described with reference to Figure 2 can be modified in a further example method, in which the pump is positioned outside the pile and an upstream conduit extends from the pump into the interior space.

[0069] Turning now to Figure 3, a further example of the installation of one of the piles 1'' is shown. The installation method in this example is similar to that described with reference to Figure 1, and similar features are indicated in Figure 3 by the same element symbols and a subsequent double apostrophe. The difference between this example of pile 1'' and the pile 1' described with reference to Figure 1 is that the peripheral wall 11'' has an intermediate section 11c'' positioned between the lower section 11a'' and the upper section 11b''. In this example, the upper section 11b'' is cylindrical in shape and has a diameter smaller than that of the lower section 11a''. The intermediate portion 11c'' is a truncated cone or conical shape and is positioned between the upper section 11b'' and the lower section 11a''.

[0070] The shape of pile 1'' is possible due to the lower load required in the driving force F'', which is made possible by the reduction of soil resistance and the removal of hydrostatic resistance inside pile 1'' during pile driving. This pile 1'' is further advantageous in that when water is removed from the internal space 13'', a hydrostatic force acts on the intermediate section 11c'' to push pile 1'' into the soil S.

[0071] In a further example, the pile 1'' shown in Figure 3 is used in the installation method described with reference to Figure 2, such that the pump 2' is positioned inside the internal space 13'.

[0072] In a further example, the pile 1'' shown in Figure 3 is used in an installation method in which a pump is positioned outside the pile and a conduit is lowered from the upper end of the pile into the internal space to pump out water.

[0073] Turning now to Figure 4, another example of a method for installing a pile 10 into the soil S is shown. In this example, the pile 10 is completely submerged underwater. The pile 10 has only one cylindrical peripheral wall 101 extending from an open lower end 102. As in the previous example, one lower end 104 of the peripheral wall 101 is driven into the soil, and a driving force F''' is used to drive the pile 10 into the soil S. Component symbol 201 represents the conduit in the embodiment shown in Figure 4.

[0074] A closure or closing member 40 is provided on the pile 10, which closes the upper end 105 of one of the peripheral walls 101. The closure 40 is temporarily attached to or engaged with the peripheral wall 101. The soil S, the peripheral wall 101, and the closure 40 define an internal space 103 of one of the piles 10. During the application of the driving force F''', water is pumped from the internal space 103 by a pump 20 in the same manner as in the example described with reference to Figures 1 and 3.

[0075] As in the previous example, a pile drive assembly can apply a driving force F''' to an anvil 30. However, since the drive member of the pile drive assembly (i.e., a hammer or similar) is positioned above water, the pile drive assembly may further include a follower 50 for transmitting energy between the anvil 30 and the pile 10. The follower 50 is an extension between the upper end of the pile and the drive member of the pile drive assembly. The follower 50 may have any suitable configuration to transmit energy in the axial direction.

[0076] In this example, the closure 40 is attached to the lower end of one of the driven members 50. That is, when the driven member 50 is engaged with the upper end 105 of the peripheral wall 101, the closure 40 closes the upper end 105 of the peripheral wall 101.

[0077] In this example, water is permitted to enter one of the internal volumes of the follower 50. For example, water may be pumped from the internal space of the pile into the internal space of the follower, or water may enter the follower through a hole therein. The water level Wf in the follower 50 may be less than, greater than, or the same as the outer water level Wo.

[0078] Advantageously, the water in the driven member 50 applies a downward force to the closing member 40, thereby pushing the pile 10 into the soil S. In some instances, the water level Wf in the driven member 50 is controlled to apply a predetermined amount of downward force to the closing member 40.

[0079] Once the pile 10 is in the embedded position, the closure 40 can be removed, and a structure connecting to the top of the pile 10 (e.g., an upper section) can be added to the pile 10. This upper section can be, for example, a sleeve structure or part of a monopile. Advantageously, this provides versatility, as one design of the pile 10 can be used for different structures. Furthermore, the upper structure does not need to be subjected to driving forces F''', thereby reducing the risk of structural damage, while also allowing for the use of lower-cost structures. Moreover, by using a short pile 10, the pile 10 can have a larger diameter and wall thickness, and thus provide a more stable foundation for the structure to be connected to it.

[0080] In another example, the method for installing a pile is the same as that described with reference to Figure 4, except that the guide tube travels through one of the holes in the closure. This example is used when there is no hole through the peripheral wall.

[0081] In any of the foregoing examples, the channel may be provided on the radially outer or radially inner wall of the perimeter wall. The channel may be integrally formed with the perimeter wall, for example, cut into the perimeter wall as a groove. The channel may be provided as a separate component and suitably attached to the perimeter wall, for example, by welding. The channel may extend from the lower end of the perimeter wall to a position above the soil height when the pile is in the embedded position. Alternatively, the channel may be a circumferential channel. The channel may facilitate or initiate the formation of flow paths through the soil, or may improve the distribution of flow paths around the perimeter wall.

[0082] In any of the foregoing examples, a control system may be provided. The pile drive assembly and / or pump may communicate with the control system. The control system controls the driving force applied by the pile drive assembly and controls the pump settings, such as the pumping rate.

[0083] In any of the foregoing examples, a sensor may be provided to measure the pressure or water level in the internal space. The sensor communicates with the control system. Measurements from the sensor can be used to control the pump by adjusting pump settings to achieve a desired pressure or water level in the internal space. Alternatively, the controller may use measurements from the sensor to control the pile drive assembly to control the magnitude of the driving force applied to the pile. Alternatively, the control system may use measurements from the sensor to detect pile descent and rapid soil penetration due to an increase in pressure in the internal space. Furthermore, if necessary, the control system may use the detection of pile descent to control the pile drive assembly to reduce the magnitude of the driving force applied to the pile or eliminate it entirely at once. Alternatively, the control system may use measurements from the sensor to determine a pressure difference between the internal and external spaces of the pile. The pressure difference can be used to calculate a downward force acting on the pile due to the pressure difference. The control system may use the downward force due to the pressure difference to control the pile drive assembly to control the magnitude of the driving force that varies according to the downward force due to the pressure difference.

[0084] Those skilled in the art will understand that the features described with respect to any of the above embodiments can be applied interchangeably between different embodiments. The embodiments described above are examples illustrating various features of the present invention.

[0085] 1: pile 1': Stake 1'': Stake 2: Pumping equipment / pump 2': Pump 2'': Pump 3:anvil 3':anvil 3'':anvil 10: piles 11: Surrounding walls 11': Surrounding wall 11'': Surrounding wall 11a: Lower section 11a': Lower section 11b: Upper section 11a'': Lower section 11b'': Upper section 11c'': Middle section 12: Lower open end 12': Lower open end 12'': Lower open end 13: Interior Space 13': Interior space 13'': Interior space 14: Bottom / Lower Edge 14': Bottom / Lower Edge 14'': Bottom / Lower Edge 15: Top 15': Top 15'': Top 20: Pump 21: Catheter 21'': catheter 22': Downstream catheter 30:anvil 40: Closure or closing component 50: Follower 101: Surrounding Wall 102: Open lower end 103: Interior Space 104: Lower end 105: Upper end 201: Catheter F: Driving force F': Driving force F'': Driving force F''': Driving force S: Soil Wi: Water level Wi': Water level Wi'': Water level Wo: water level Wf: Water level

Claims

1. A method for driving an offshore pile (1) into soil (S), the method comprising: Provide a pile, the pile including a peripheral wall (11) extending from one open end (12); The pile is positioned in a first location, wherein the lower open end of the peripheral wall is closed by the soil to define an interior space (13) inside the peripheral wall; a pile drive assembly is provided coaxially at or in one of the upper ends (15) of the pile; a pumping device (2) is provided at a location adjacent to the pile; a driving force (F) is applied to the pile using the pile drive assembly to drive the pile into the soil; and during the application of the driving force, water is pumped from the interior space using the pumping device to lower the water level (Wi) in the interior space, such that water flows from the outside of the pile through the lower open end of the peripheral wall into the interior space, wherein the water level (Wi) in the interior space (13) is lowered by pumping water from the interior space (13) to a level below or far below the water level outside the pile (1), characterized in that the method further includes: providing a sensor, wherein the sensor is disposed in the interior space (13), Using the sensor to measure either the pressure in the interior space (13) or the water level (Wi) in the interior space, the pile (1) includes a lower section (11a) having a first diameter and an upper section having a second diameter smaller than the first diameter, wherein applying a driving force (F) to the pile to drive the pile into the soil involves driving a portion of the lower section (11a) of the pile (1) into the soil.

2. The method of claim 1, wherein pumping water and applying a driving force (F) are performed simultaneously to reduce resistance from the soil (S), which acts against the movement of the lower open end (12) of the peripheral wall (11) into the soil.

3. The method of request item 1 or 2, wherein the method further includes: Based on the measurements from the sensor, the pumping parameters of the pumping device are determined, and the pumping device is operated using the determined pumping parameters.

4. The method of request item 1 or 2, wherein the pile is a single pile or a set of pipe piles.

5. The method of claim 1 or 2, wherein the water flow from the outside of the pile to the interior space (13) includes at least one of the following: water flow adjacent to a lower edge (14) of the peripheral wall (11); water flow passing through the soil (S) adjacent to a radially outer surface of the peripheral wall; water flow passing through the soil adjacent to a radially inner surface of the peripheral wall.

6. The method of claim 1 or 2, wherein the water flow from the outside of the pile (1) to the interior space (13) includes water flowing through at least one channel located in one of the radially outer surfaces of the peripheral wall (11).

7. The method of claim 1 or 2, wherein the water is pumped out of the interior space (13) through one of the openings in the peripheral wall (11) of the pile (1).

8. The method of claim 1 or 2, wherein the pile (1) or the pile drive assembly further includes a closing member (40) that closes an open end of one of the peripheral walls (11).

9. The method of claim 8, wherein water is pumped out of the interior space (13) through one of the openings in the closure (40).

10. The method of claim 1 or 2, wherein the pile drive assembly applies a regular axial load action including a predetermined sequential impact.

11. The method of claim 1 or 2, wherein the pile drive assembly applies a regular axial load including a vibration load.

12. The method of claim 1 or 2, wherein when the pile is positioned in the first position, a pile holder is used to hold the pile in a vertical orientation.

13. The method of claim 1 or 2, wherein the step of positioning the pile (10) in the first position includes lowering the pile onto the soil (S) to the first position, wherein the weight of the pile causes the peripheral wall (11) to penetrate the soil.

14. As in request item 1 or 2, wherein, Once the pile is driven into the soil to a predetermined depth, it is configured to support a structure above water, such as a wind turbine.

15. The method of claim 1 or 2, wherein sealing all underwater openings in the pile further includes the open end of the peripheral wall closed by the soil, and further includes any opening through which water is pumped.

16. The method of claim 1 or 2, further comprising connecting the upper section to the lower section (11b) after the portion of the lower section (11a) has been driven into the soil (S).

17. The method of claim 1 or 2, wherein the pile further includes an intermediate section located between the lower section and the upper section, the intermediate section being a truncated conical shape.

18. A system for driving an offshore pile (1) into soil (S), the system comprising: A pile, comprising a peripheral wall (11) extending from a lower open end (12); a positioning device for positioning the pile in a first position, wherein the lower open end of the peripheral wall is closed by the soil to define an interior space (13) inside the peripheral wall; a pile drive assembly for applying a driving force (F) to the pile to drive the pile into the soil, wherein, in use, the pile drive assembly is coaxially configured at or in one upper end (15) of the pile; and a pumping device (2) for pumping water from the interior space during the application of the driving force to lower the water level (Wi) in the interior space, such that water flows from the outside of the pile through the lower open end (12) of the peripheral wall into the interior space; The system is characterized in that the pile (11) includes a lower section (11a) having a first diameter and an upper section (11b) having a second diameter smaller than the first diameter, wherein applying a driving force (F) to the pile (1) to drive the pile (1) into the soil (S) involves driving a portion of the lower section (11a) of the pile (1) into the soil; and the system further includes a sensor configured to measure the pressure in the interior space (13) or the water level (Wi) in the interior space.

19. The system of claim 18 further includes a closing member (40) configured to close one of the open ends of the peripheral wall (11).

20. The system of claim 18 or 19 further includes a pile holder that can be used to hold the pile (1) in a vertical orientation when the pile is positioned in the first position.

21. The system of claim 18, wherein the pile further includes an intermediate section located between the lower section and the upper section, the intermediate section being a truncated conical shape.

Images