Improved device for mild driving of pile

Abstract

The invention belongs to the field of pile foundations for supporting buildings and the like. The piles may provide support for onshore or offshore structures such as high-rise buildings and wind turbines. The invention is particularly suited for driving piles of various sizes, which are typically used for softer non-cohesive soils, such as sandy soil.

Description

Technical Field

[0001] The present invention relates to the field of pile foundations for supporting structures and the like. Piles can provide support for onshore or offshore structures such as high-rise buildings and wind turbines. The present invention is particularly suitable for driving piles of various sizes, which are typically used in soft, non-cohesive soils such as sand. Background Art

[0002] The present invention relates to the field of piling. Typically, piles are driven into the soil by repeatedly striking the top of the pile with a hammer or counterweight. In areas with relatively soft soil, or where piles are needed as supports for man-made structures, for example, relatively large numbers of piles are driven into the soil. This type of piling creates a noise nuisance to the environment. Furthermore, this type of piling exerts forces on the pile, which can weaken or damage it.

[0003] GB 1066247 (A) describes a vibratory hammer for driving a member (such as a pile), which has a vertical action and a rotary action and comprises two shafts mounted on a support housing and provided with gears and discs, which are fitted with counterweights so that when the two shafts rotate in opposite directions, they exert a vibratory torque on the support housing, thereby rotating the support housing and causing the impact member to strike the anvil portion of the housing. This document is more concerned with drilling using the rotary vibration (somewhat confusingly referred to as torsion) of the pile about a horizontal axis. In addition, the rotation of the individual masses is coupled (see Figure 1 US 3 583 497 A and CN 110 424 384 B relate to further background art.

[0004] A technique for gentle pile driving using vibration has recently been developed. WO 2021 / 040523 A1 describes a vibration device for this purpose. This device uses a combination of vertical and torsional vibrations. Eliminating vertical vibration is advantageous, as ground vibration and noise are undesirable. However, pure torsional excitation does not always ensure that a pile is driven to its final penetration point. Therefore, while vibration devices perform well in many situations and environments, this is not always the case.

[0005] The present invention therefore relates to an improved pile and pile driver and method for pile driving which solve one or more of the above-mentioned problems and disadvantages of the prior art, providing reliable results without compromising functionality and advantages. Summary of the Invention

[0006] The object of the present invention is to overcome one or more limitations of prior art piles and pile drivers and pile driving methods and to at least provide an alternative thereto. The friction between a pile and the soil is generally considered to consist of two parts: pile side friction resistance (along the side of the pile) and pile end resistance (under the pile). Pile side friction resistance is naturally minimized by torsional vibration and is therefore primarily addressed by a vibrating device in a manner that gently drives the pile. Pile end resistance cannot be overcome by torsional excitation. In the present invention, in particular, the pile end resistance is minimized by modifying the profile of the pile end. Such a pile profile design can be achieved in several ways. In a first aspect, the present invention relates to a supporting monopile for gentle driving into soil, wherein the monopile is made of a first material selected from concrete, a metal such as iron and combinations thereof, and includes a monopile end driving resistance reducing device, wherein the pile end resistance reducing device is selected from a circumferential discontinuity, a circumferential continuous profile, a hardened coating and combinations thereof, the monopile being in particular a monopile having a length of 5-100 m and a diameter of 0.5-20 m. As a result, the resistance to driving the support monopile into the soil is typically reduced by 10-90%, and in particular by 20-50%, compared to a monopile without a resistance-reducing device. It has been found that the pile tip resistance can be minimized or at least reduced by modifying the pile tip profile. Such pile profile design can be achieved in a variety of ways: by creating teeth of varying shapes (interrupted profiles), by forming a smooth (continuous) profile design (e.g., a wavy shape), by reducing the pile thickness at the tip section (e.g., by making the edge "sharper"), by applying a non-stick coating (the term "non-stick" is used here to refer to the surrounding soil, ensuring that the soil does not adhere to the pile tip), by applying a hardening coating to the pile tip, and any combination of these methods. The precise modification typically depends on the pile size on the one hand and the soil properties on the other. Substantially different pile profile designs can be applied for different soils. Another advantage is that the monopile's drivability is improved, thereby accelerating installation, reducing offshore vessel construction time, and thus significantly reducing wind farm installation costs. It has further been found that the load-bearing capacity of the monopile is primarily determined by the pile side friction resistance, with the pile tip playing a secondary role. Furthermore, it should be noted that measuring pile bearing capacity by performing standard tests can help determine the minimum allowable wall thickness or even help confirm that the pile tip geometry has no effect on the final pile bearing capacity.

[0007] In a second aspect, the invention relates to a vibration device (1) for gentle driving of a monopile, the vibration device comprising: a holder (9) for mechanically fixing a vibrator (3) to the monopile; at least one actuator (4); the vibrator (3) configured to provide vertical vibration of the monopile at a first vibration frequency and to provide torsion to the monopile at a second torsion frequency; a controller for driving the at least one actuator (4), in particular a monopile according to the invention. The term "frequency" is used to denote any form of (vibration) repetition, which may be sinusoidal, a combination of sinusoidal repetitions, a complex (vibration) form, etc., depending on the vibrator used and its operating mode.

[0008] In a third aspect, the invention relates to a method for driving a monopile into soil, the method comprising: providing a vibration device (1) according to the invention, mounting the vibration device (1) on a monopile according to the invention, and driving the monopile into soil.

[0009] In a fourth aspect, the invention relates to a kit of parts comprising a vibration device according to the invention, the vibration device comprising a holder (9), a vibrator (3), at least one actuator (4), a controller and at least one of a monopile according to the invention.

[0010] The present invention may be considered to relate to a vibration device which causes torsional vibrations about a vertical axis as well as vertical vibrations. The torsional vibrations typically occur at a much higher frequency than the vertical vibrations and are considered to continuously disrupt the static friction of the pile with the surrounding soil. The vertical vibrations drive the pile into the soil when the connection between the pile and the surrounding soil is broken. In a first aspect, the present invention relates to a vibration device for gentle pile driving, the vibration device comprising: a holder for mechanically fixing the vibrator to the pile and thereby for transferring vibration energy to the pile; a vibrator adapted to provide vertical vibrations of the pile at a first vibration frequency and to provide torsion to the pile at a second, typically much higher, torsional frequency, wherein the vibrator comprises at least two groups (i≥2) of eccentric masses, each group i comprising at least two equal masses j, wherein each individual mass m i,j Located at a distance d from the vibrator i The distance is usually a distance parallel to the axis of rotation, such as distances d1 and d2, where the mass m i,j Attached to at least one horizontal axis ha i At least one motor, the at least one motor for making the mass m i,j Around its horizontal axis ha i Rotate so that in group i, mass m i,j Along the horizontal axis ha i At the same angular velocity ω i Rotation, where the angular velocity ωi Different from the angular velocity ω i+1 , where the torsional frequency is usually greater than the vertical vibration frequency, usually several times greater, and in group i+1, the mass m i+1,j Along the horizontal axis ha i+1 With opposite angular velocity ω i+1 Rotation; and a controller for driving at least one motor and for controlling the mass m i,j Each individual angular velocity ω of group i i , for controlling the sum of the horizontal forces generated by the individual masses and for balancing the sum of the vertical forces generated by the individual masses. In addition to these forces, gravity pulls the pile's mass downward. Thus, the controller can balance the forces in the z-direction and sum the forces in the x-direction (or equivalently, the y-direction, or the combined x+y-direction), where the z-direction is parallel to the pile axis and the x- and y-directions are perpendicular to the pile axis, for example, in a Cartesian coordinate system. The vibration device can drive the pile into the soil by combining torsional vibrations, typically at high frequencies (or vibration modes when the excitation is harmonic), with vertical vibrations, typically at low frequencies (or vibration modes when the excitation is harmonic). No additional pile-driving mechanism, such as a hammer, is required. The eccentric masses of these pile-driving mechanisms typically rotate at high speed. Typically, the masses are positioned so that, at a specific location, they generate two opposing forces, a torque in a torsional direction along the longitudinal axis of the pile, and zero force at another location. The vibration device and the present method are faster and quieter. For example, for a medium-sized pile, such as 10 meters long and approximately 75 cm in diameter, the driving speed is twice that of the prior art. The pile can be moved downward at a speed of approximately 30 cm / s. Furthermore, compared to an impact hammer, the pile deforms only minimally or with minimal force. The energy generated by the vibration device is primarily used to drive the pile. Reference is made to the aforementioned WO 2021 / 040523 A1, the contents of which are incorporated herein.

[0011] This specification describes the advantages of the present invention in detail. DETAILED DESCRIPTION

[0012] Some typical dimensions and features of a wind turbine can be:

[0013] DNV-OS-J101-2007: Design of offshore wind turbine structures

[0014] DNV-RP-C203: Fatigue design of offshore steel structures

[0015] Steel grade: S355

[0016] Yield strength: 355MPa

[0017] Elastic modulus E = 210 GPa

[0018] Poisson's ratio ν = 0.3

[0019] Linear thermal expansion coefficient (T≤100℃) α=12e-6K-1

[0020] Some material coefficients:

[0021] – Ultimate limit state strength check, γs=1.10

[0022] –ULS buckling check, γs=1.20

[0023] – Normal service limit state, γs=1.00

[0024] –Seismic limit state, γs=1.15

[0025] Model: REpower 5M (5.0MW)

[0026] Turbulence intensity level: IEC Ib / GL offshore type I

[0027] Structural design life: 25 years

[0028] Hub height: 85m above sea level

[0029] Blade height: 153m above sea level

[0030] Rotor diameter: 126m

[0031] Swept area: 12'469m 2

[0032] Nacelle mass (without rotor): 290 tons (approximately)

[0033] Rotor: 120 tons (approximately)

[0034] Cut-in wind speed: 3.5m / s

[0035] Rated wind speed: 13.0m / s

[0036] Cut-out wind speed: 30m / s

[0037] Running rotor speed: 7.7-12.1rpm

[0038] Rated rotor speed: 10.5 rpm

[0039] Structure type: steel pipe

[0040] Tower size

[0041] Base: D = 6.00m, t = 35mm

[0042] Top: D = 4.50m, t = 20mm

[0043] Initial mass estimate = π*5.25*0.0275*70*7,850=250t

[0044] In an exemplary embodiment of the monopile, circumferential interruptions are provided in the longitudinal direction of the monopile, wherein 1 to 10 circumferential interruptions are provided, wherein each circumferential interruption has a height of 0.5-50 cm and a length of 0.5-50 cm, respectively.

[0045] In an exemplary embodiment of the monopile, circumferentially continuous contours are provided in the longitudinal direction of the monopile, wherein 1 to 10 circumferentially continuous contours are provided, wherein each circumferentially continuous contour has a height of 0.5-50 cm and a length of 0.5-50 cm, respectively.

[0046] In an exemplary embodiment of the monopile, the monopile has a tapering thickness of 0.1-50% of the diameter.

[0047] In an exemplary embodiment of a monopile, the sharp edge has an edge width of 0.2-10 cm.

[0048] In an exemplary embodiment of the present monopile, the hardening coating is selected from an alloy, for example a Si alloy such as SiC.

[0049] In an exemplary embodiment of the present monopile, the monopile comprises a second material, wherein the second material is bonded to the first material, wherein the second material is selected from the group consisting of a polymer, a resin such as an epoxy, graphene, and carbon nanotubes.

[0050] As described above, the exemplary embodiments described above reduce resistance when driving a monopile into soil.

[0051] In an exemplary embodiment of the vibration device, the vibrator comprises at least two groups (i≥2) of eccentric masses, each group i comprising at least two equal masses j, wherein each individual mass m i,j Located at a distance d from the center of rotation of the vibrator i At one side, the mass block m i,1 Relative to the mass block m on the other side i,2 Shift 180 degrees, or the mass m i,1 and m i,2 Counter-rotation, where mass m i,j Attached to at least one horizontal axis ha i , wherein at least one actuator (4) is used to make the mass m i,j Around its horizontal axis ha i Rotate so that in group i, mass m i,j Along the horizontal axis ha iAt the same angular velocity ω i Rotate, and in group i+1, mass m i+1,j Along the horizontal axis ha i+1 With opposite angular velocity ω i+1 Rotation, where the angular velocity ω i Different from the angular velocity ω i+1 , where the controller is configured to control the mass m i,j Each individual angular velocity ω of group i i , used to control the sum of the horizontal forces generated by each mass block, and to balance the sum of the vertical forces generated by each mass block.

[0052] In the present vibration device, the vibrator comprises: at least one pair of at least two vertically oriented equal masses, in particular linear actuators, such as linear pistons Vp, configured to move in a reciprocating manner i,j and at least one horizontally oriented mass configured to move in a reciprocating manner, such as at least one pair of at least two horizontally oriented equal masses configured to move in a reciprocating manner, in particular a linear actuator, such as a linear piston hp i,j , wherein each individual piston is configured to provide linear motion of its cylinder, wherein the cylinders of at least two vertically oriented masses are configured to move in a reciprocating manner, such as a linear piston vp i,j Each is individually configured to vpi Operation, generating reciprocating vertical velocity rv vi , wherein the cylinders of at least two horizontally positioned masses are configured to move in a reciprocating manner, such as linear pistons each individually configured to move at a frequency ω hpi Operation, generating reciprocating horizontal speed rh vj , wherein in each pair, the cylinders are configured to move in opposite directions, e.g., 180 degrees out of phase, and wherein in each pair of linear pistons, each piston is individually located a distance d from the center of rotation of the vibrating device i The reciprocating movement is in the vertical or horizontal direction, respectively. The mass can be driven by an actuator, such as a piston in which the mass is withdrawn and retracted, the mass being driven by a motor (such as an electric motor, etc.). Likewise, any pair of reciprocating masses can be used, such as cylinders. Thus, a centrally located vertical cylinder is provided. This vertical cylinder provides vertical vibration (see Figure 4a By varying (usually by selecting) the stroke of the cylinder, the amplitude can be adjusted, and by varying (usually by controlling) the speed at which it moves, the frequency ω can be adjusted. pi. In this way, frequency and amplitude remain independent of each other. In principle, more vertical cylinders can be used. If more vertical cylinders are used, they are positioned equidistant from the center of the pile, at least in pairs, and optionally all equidistant from the center of the pile. The same is true for the horizontal cylinders. They are positioned tangentially with respect to the pile to be driven, therefore horizontally. The strokes are synchronized, operating at the same frequency, but in opposite directions, such as 180 degrees out of phase, i.e. one moves in a first direction and the other moves in its opposite direction (see green and red arrows; colors are used to distinguish between extraction and retraction). It is possible to have more cylinders placed on the pile. They extend and retract simultaneously. The vertical and horizontal cylinders (or pistons) can be operated at different frequencies, and for any given pair of horizontal and vertical cylinders, typically ω hpi ≠ω vpi Arrays of cylinders can also be considered; where each group or pair (e.g. horizontal cylinders) can have subgroups operating at different frequencies (e.g. 50% of the cylinders operate at a higher frequency and 50% at a lower frequency, and so on). In this way, non-pure sinusoidal vibrations are generated and more complex forms of vibration can be provided if desired. The linear actuator can be selected from hydraulic cylinders, electric cylinders, pneumatic cylinders and piezoelectric stacks.

[0053] In exemplary embodiments of the present vibratory device, the centre of mass of the vibratory device and the axis of rotation of the pile may coincide, typically within a few percent, for example within 5%.

[0054] In an exemplary embodiment of the present vibration device, the vibration device may include at least one gear adapted to be driven by at least one actuator and adapted to cause at least one mass m to move. i,j The rotation preferably causes both masses within a group i to rotate. This allows for a good and simple control of the forces and their adaptation during pile driving. In an example, the masses of different groups can be driven by the same gear.

[0055] In an exemplary embodiment of the present vibration device, the first group may include a mass m 1,1 and mass m 1,2 , the second group may include mass m 2,1 and mass m 2,2 , and optionally other groups may include mass m i,1 and mass m i,2 Therefore, a wide variety of masses and many groups can be used. Typically, for simplicity of construction, only a limited number of groups, such as two, are used, but the invention is not limited thereto.

[0056] In an exemplary embodiment of the present vibration device, the controller can be adapted to control the sum of the vertical forces to be offset by the group. By varying the angular velocity, typically through careful selection and balancing of mass, radius, and / or distance, the sum of the vertical forces is offset. This results in a very stable and minimally noisy operating mode.

[0057] In an exemplary embodiment of the present vibration device, the addition of horizontal forces can be controlled. As with the vertical forces, the horizontal forces can be controlled by varying the angular velocity and, typically, by carefully selecting and balancing the masses and radii and / or distances.

[0058] Furthermore, vertical forces can still be generated, for example at low frequencies. In any case, the mass of the pile and gravity combine with the torsion to drive the pile into the soil.

[0059] In the exemplary embodiment of the present vibration device in the i-th group, the first mass m i,1 Can be located at a first distance d from the vibrator side i At, and the second mass block m i,2 may be located at the same first distance d from the side of the vibrator opposite to the first mass i In a group, the masses are usually located "opposite" to each other relative to the position of the vibrator.

[0060] In an exemplary embodiment of the present vibration device, the at least one actuator may each independently be adapted to rotate the horizontal axis ha at 10-200 Hz (600-12000 rpm), preferably 20-180 Hz, more preferably 30-150 Hz, even more preferably 40-120 Hz (such as 50-100 Hz, for example 60-80 Hz). i Rotate.

[0061] In an exemplary embodiment of the present vibration device, the at least one first actuator may be each independently adapted to move the horizontal rotation axis ha at a first vibration frequency of 10-50 Hz (600-3000 rpm), preferably 12-30 Hz, more preferably 15-25 Hz (such as 16-24 Hz). i Rotate.

[0062] In an exemplary embodiment of the present vibration device, the at least one second actuator may be each independently adapted to rotate the horizontal axis of rotation ha at a second torsional frequency of 15-200 Hz (900-12000 rpm), preferably 30-150 Hz, more preferably 50-100 Hz (such as 60-80 Hz). i Rotate.

[0063] In an example, the first vibration frequency may be 1400 rpm and the second torsional frequency may be 4800 rpm.

[0064] In an exemplary embodiment of the present vibration device, at least one second angular torsional velocity ω i It can be the first angular vibration velocity ω i+1 At least twice, preferably, where at least one angular velocity ω i is the angular velocity ω i+1 More preferably, it is at least four times as much, more preferably at least ten times as much, such as at least 50 times as much.

[0065] In an exemplary embodiment of the present vibration device, the mass m i,1 and m i,2 Can be located at a distance ha from the horizontal rotation axis i The distance e i At, and where the mass m i+1,1 and m i+1,2 Can be located at a distance ha from the horizontal rotation axis i+1 The distance e i+1 Place.

[0066] In an exemplary embodiment of the present vibration device, the mass m i,j It can be a radius of e i The center of mass of the disk-shaped mass block is respectively aligned with the rotation axis ha i Thus, a well-balanced mass can be provided.

[0067] In an exemplary embodiment of the present vibration device, the mass ratio m i+1,1 / m i,1 can be equal to e i / e i+1 Thus, the forces of group i and group (i+1) can be balanced, typically to within 1% or less, eg, completely balanced.

[0068] In an exemplary embodiment, the vibration device may include two groups of masses, wherein the horizontal rotation axes ha1 and ha2 are equidistant from the center point of the vibration device, thereby balancing the forces of the i-th group and the i+1-th group.

[0069] In an exemplary embodiment of the present vibration device, the mass may be disc-shaped. It has been found that a disc-shaped mass is easy to attach to the shaft.

[0070] In an exemplary embodiment of the present vibration device, the mass may be 5-5000 g, preferably 10-1000 g, such as 30-600 g, for example 50-400 g. For larger piles and / or more cohesive soils and / or harder soils, a larger mass may be used. Additionally or alternatively, the angular velocity may be increased.

[0071] In the exemplary embodiment of the present vibration device, the distance / radius e i1-50 cm, preferably 2-40 cm, such as 3-30 cm.

[0072] In an exemplary embodiment of the present vibration device, the controller may drive at least one actuator in phase, for example, such that F z1 =-F z2 , usually with an accuracy of within 1%, such as the dimensions being exactly equal.

[0073] In an exemplary embodiment of the present vibrator, the vibrator may include a receiving structure, such as a groove. Thus, the stake may be securely attached to the present vibrator.

[0074] In an exemplary embodiment of the present vibration device, the controller may be adapted to provide a vertical drive frequency of 10-50 Hz.

[0075] In an exemplary embodiment of the present vibration device, the vibration device is configured to adjust at least one distance d i , in particular wherein the vibration device is configured to adjust all distances d i .

[0076] In an exemplary embodiment of the present vibration device, the holder (9) is configured to secure the vibration device to the outside of the monopile, the inside of the monopile, over the edge of the monopile, and combinations thereof.

[0077] In an exemplary embodiment of the present method, the vibrator is calibrated before the pile is driven into the soil. Thus, the driving force, angular velocity, soil properties, interaction between the pile and the soil, etc. can be better controlled.

[0078] The present invention will be further described below by the following examples, which are exemplary and explanatory and are not intended to be considered as limitations of the present invention. It will be apparent to those skilled in the art that many variations, whether obvious or not, may be conceivable within the scope of protection defined by the present claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 、 Figure 2 、 Figures 3a to 3d Some details are shown.

[0080] Figures 4a to 4g An alternative embodiment is shown that includes a piston.

[0081] Figure 5a to Figure 5b An exemplary monopile is shown.

[0082] Figures 6a to 6c The experimental results are shown.

[0083] Detailed description of the drawings

[0084] In the attached figure:

[0085] 1. Vibration device

[0086] 2-axis

[0087] 3. Vibrator

[0088] 4 Actuators

[0089] 8 bearings

[0090] 9 Fixer

[0091] 18 gears

[0092] 21 fixture

[0093] 22 Axis

[0094] 25 Gear

[0095] 26 fixture

[0096] 27 Engine

[0097] 29 Gear

[0098] 31 Safety clamp

[0099] 32 ball bearings

[0100] 33 Spacer

[0101] 34 Spacers

[0102] 35 fixture

[0103] 36 bracket + holder

[0104] 43 bracket + fixer

[0105] d i Mass block m i,j Distance i from the vibrator side

[0106] e i Mass block m i,j Distance from horizontal rotation axis ha i The distance i

[0107] ha i Horizontal axis i

[0108] m i,j Mass j of group i

[0109] ω i Angular velocity i

[0110] Figure 1An example of a prototype of the present vibration device mounted on a pile is shown. The body is machined to house the main components of the vibration device (actuator, gears, shaft, and mass) in an efficient manner and to ensure that the center of mass falls in the desired position. The vibration device includes an actuator that provides input energy. Three gears are used to transmit force from the actuator to two shafts, which contain a total of four eccentric masses, two on each shaft. When the masses begin to rotate, centrifugal force is generated, and this centrifugal force is transmitted to the pile in the form of torque.

[0111] Figure 2 A top view of the prototype vibration device is shown, revealing the relative spatial positions of the masses and the main distances (d1, d2, e1, e2) from the body.

[0112] Example

[0113] The design and function of a small vibration device are described in detail. An explanation of how the vibration device works is given, along with a technical diagram showing an overview of the device's mechanical components, a description of the frequency control system of the electric actuator, a parametric study of the expected forces and moments generated by the vibration device, and some safety recommendations and instructions.

[0114] like Figure 1 As shown in Figure 1, the vibration device is designed to be mounted on top of a small pile. The vibration device generates a force through counter-rotating masses that are offset from the center of rotation. And, by pairing this force with another force of opposite sign, a torque is generated. Figure 1 , the moment is only effective about the z-axis. This means that only when the mass is in Figure 1 The torque only applies when the vibration device is in the position shown and rotated 180 degrees relative to the drawn position. This generates a harmonic torque that is transmitted to the top of the pile. The system is driven by a frequency-controlled electric actuator. A feedback loop can also be set up to provide a measurement of the actual force and / or angular rotation, compare the measured values with the current values, and optionally correct the measured changes, for example by increasing or decreasing the angular velocity. This can be done for the entire system or for parts of it, such as a set of masses i. In addition, the masses and positioning are variable. This provides sufficient flexibility to generate the desired torque. The components are selected so that the vibration device can operate correctly for a long time. Figure 3 depicted below shows the technical details of the final prototype design of the vibration device.

[0115] The force F generated by a single rotating mass z will be offset at all θ angles by the force generated by the other shaft running in opposite phase, and the same offset will occur at the other end of the shaft. x In the case of θ, the force is canceled at all angles θ, but at 0 and 180 degrees, F xmaximum. Assuming the two masses on one side are displaced 180 degrees relative to the two masses on the other side, a moment about the z-axis is generated. The reason for using two masses on each side of the vibration device is to cancel the moments generated about the x-axis when the masses are positioned at 90 and 270 degrees relative to the origin (which is assumed to be in the position shown in the figure). Given the different eccentricity, the masses must also be different. Given the alignment of the axes in the x-direction, no moment about the y-axis is expected. Finally, as an example of a specific case study, the figure below shows the variation of forces and moments across the entire envelope.

[0116] Figure 2 The vibration setup is presented, and the relevant parameters used for the analysis are described. For the case study, the following values are selected: m1 = 10 g, e1 = 5 cm, e2 = 8 cm, d1 = 10 cm, d2 = 15 cm, and m2 = m1e1 / e2 = 6.3 g. The mass m2 is calculated so that the resultant moment about the x-axis is zero. Due to practical spacing, the distances d1 and d2 must be different. Therefore, the resultant forces in the x-direction add, while the forces in the z-direction cancel each other, summing to zero.

[0117] exist Figures 3a to 3d In Figure 1, the components that make up an example of this prototype vibration device are listed, and a description of the utility of each component in the vibration device is given below. Component 27 corresponds to the engine that provides power and moves the eccentric mass. Components 43 and 36 include support plates and fixtures for the engine, which ensure the correct positioning of the engine shaft with the drive shaft gear 29 and clamps 35 to avoid slippage between the engine shaft and the drive shaft. A set of gears 18 and 25 is used to transmit the engine torque to shafts 2 and 22. In order to ensure correct alignment between the gears, a safety clamp is used in the power gear 31. Clamp 26 is used to ensure that the eccentric mass remains in place during movement of the shaft. In the side view of the figure, components 8 and 21 include bearings and clamps, respectively.

[0118] Figure 3c A top view of the vibration device is shown. Component 32 comprises ball bearings to allow the engine shaft to rotate, and components 33 and 34 comprise spacers to ensure proper connection between components of the powertrain.

[0119] The actuators of vibration devices can reach high speeds, so it's important to take safety precautions before starting the device. 1. Ensure that replaceable components, such as the attached mass and restraining bolts, do not become dislodged during operation. Even if this occurs, some form of protection should be provided during operation, and no one should be near the vibration device. 2. The simulated maximum force generated by the vibration device during operation on the shaft is 400 N (per eccentric counterweight). Any misalignment could cause slight bending of the shaft, making the vibration device unstable and its behavior unpredictable. Therefore, it is preferable to use a disc-shaped mass with its center of mass and axis of rotation coincident, or two equal masses at equal distances from the shaft. 3. The gear is secured to the shaft by a set screw. To prevent scratching the shaft, a small piece of copper is placed between the set screw and the shaft. Be careful not to let the copper fall out when removing the gear. 4. The actuator shaft is clamped to the drive shaft by a clamping nut (MLN8). The specified tightening torque is 24.5 Nm. Therefore, laboratory-scale piles were driven into the soil many times without any problems.

[0120] Figures 4a to 4g An alternative exemplary embodiment is shown, which comprises two horizontally moving pistons 3 and one vertically moving piston 3 .

[0121] Figure 5a to Figure 5b An exemplary monopile is shown. Figure 5a The sawtooth profile is shown in Figure 5b The wavy structure is shown in FIG. It has been found that these single piles can be driven into the soil more quickly (5-30% faster in time) than the same piles without such pile end resistance reducing devices. This is in addition to the advantages of the pile driver of the present invention over the cited prior art.

[0122] Figure 6a 、 Figure 6b The sinusoidal input signal to the vibration device is shown. The wider amplitude represents the torsional vibration signal of the response (t), while the smaller amplitude represents the vertical response (v).

[0123] Figure 6c The penetration depth is shown as a function of time and applied force. In this figure, the GDP is shown on the left. This indicates that a pile has been driven using the GDP technique. The solid line represents a pile without a profile, while the dashed line represents a sinusoidal profile and a dot-dash profile with a toothed end profile. The figure clearly shows that the GDP vibrator performs better than the prior art; the profiled pile performs even better.

Claims

1. A supporting monopile for gentle driving into soil, wherein: The monopile is made of a first material selected from the group consisting of concrete, metal such as iron, and combinations thereof, and comprises: A monopile end driving resistance reducing device is provided, wherein the pile end resistance reducing device is selected from circumferential discontinuities, circumferential continuous profiles, hardened coatings and combinations thereof; the monopile is particularly a monopile with a length of 5-100m and a diameter of 0.5-20m.

2. The monopile according to claim 1, wherein: The circumferential interruptions are arranged in the longitudinal direction of the monopile, wherein 1 to 10 circumferential interruptions are provided, wherein each circumferential interruption has a height of 0.5-50 cm and a length of 0.5-50 cm, respectively.

3. The monopile according to any one of claims 1 to 2, wherein: The circumferentially continuous contours are arranged in the longitudinal direction of the monopile, wherein 1 to 10 circumferentially continuous contours are provided, wherein each circumferentially continuous contour has a height of 0.5-50 cm and a length of 0.5-50 cm, respectively.

4. The monopile according to any one of claims 1 to 3, wherein: The hardening coating is selected from an alloy, for example a Si alloy such as SiC.

5. The monopile according to any one of claims 1 to 4, wherein: The monopile comprises a second material, wherein the second material is bonded to the first material, wherein the second material is selected from the group consisting of a polymer, a resin such as an epoxy, graphene, and carbon nanotubes.

6. A vibration device (1) for gentle driving of a single pile, the vibration device comprising: a fixture (9) for mechanically fixing the vibrator (3) to the monopile, at least one actuator (4), a vibrator (3) configured to provide vertical vibration of the monopile at a first vibration frequency and to provide torsion to the monopile at a second torsion frequency, a controller for driving the at least one actuator (4), wherein the vibrator comprises: at least one pair of at least two vertically oriented equal masses configured to move in a reciprocating manner, at least one horizontally oriented mass configured to move in a reciprocating manner; and in particular A monopile according to any one of claims 1 to 5.

7. The vibration device according to claim 6, wherein The vibrator includes at least one pair of at least two vertically oriented equal masses selected from a vertical linear actuator configured to move in a reciprocating manner, and at least one horizontally oriented mass configured to move in a reciprocating manner, such as at least one pair of at least two horizontally oriented equal masses selected from a horizontal linear actuator configured to move in a reciprocating manner, and wherein each pair of masses is configured to move in a reciprocating manner.

8. The vibration device according to claim 6 or 7, wherein: Vertical linear actuator is selected from linear piston vp i,j , and / or Horizontal linear actuators, such as linear pistons hp i,j , and / or wherein each individual piston is configured to provide linear motion of its cylinder, wherein the cylinders of the at least two vertically oriented masses are configured to move in a reciprocating manner, such as a linear piston vp i,j Each is individually configured to reciprocate at a vertical velocity rv vi operation, wherein the cylinders of the at least two horizontally oriented masses are configured to move in a reciprocating manner, such as linear pistons each individually configured to reciprocate at a horizontal velocity rh vj operation, wherein each pair of cylinders is configured to move in opposite directions, such as 180 degrees out of phase, particularly such as linear pistons, wherein each piston is individually located a distance d from the center of rotation of the vibrator i Place.

9. The vibration device (1) according to any one of claims 6 to 8, wherein the at least one actuator (4) is each individually adapted to rotate the horizontal axis ha at 10-200 Hz (600-12000 rpm) i Rotate, and / or wherein the mass is 5-5000 g, preferably 10-1000 g, such as 30-600 g, and / or where distance / radius e i 1-50 cm, preferably 2-40 cm, such as 3-30 cm, and / or wherein the controller drives the at least one actuator (4) in phase, and / or wherein the vibration device comprises a receiving structure, such as a groove, and / or wherein the controller is configured to provide a vertical drive frequency of 10-50 Hz, and / or Provided that no other drive means are present and / or The fixer (9) is configured to fix the vibration device on the outside of the monopile, the inside of the monopile, above the edge of the monopile, or a combination thereof.

10. A method of driving a monopile into soil, the method comprising: A vibration device (1) according to any one of claims 6 to 9 is provided, installing the vibration device (1) on a monopile according to any one of claims 1 to 5, and The monopile is driven into the soil.

11. The method according to claim 10, wherein: Before driving the monopile into the soil, the vibrator is calibrated.

12. A kit of parts comprising a vibration device according to any one of claims 6 to 9, the vibration device comprising a holder (9), a vibrator (3), at least one actuator (4), a controller and at least one of the monopile according to any one of claims 1 to 5.

Images