Pile modification for gentle pile driving

Abstract

The present invention relates to the field of pile foundations used to support buildings etc. Piles can be used as supports for onshore and offshore structures such as high rise buildings and wind turbines. The invention is particularly suitable for driving piles of any size commonly used in soft, non-cohesion-free soils such as sandy soils.

Description

Detailed Description of the Invention

[0001] The present invention relates to the field of pile foundations used to support buildings etc. Piles can be used as supports for onshore and offshore structures such as high-rise buildings and wind turbines. The invention is particularly suitable for driving piles of any size commonly used in soft, cohesionless soils such as sandy soils. [Background technology] The present invention relates to the field of pile driving. Typically, piles are driven into the soil by repeatedly dropping a hammer or weight onto the top of the pile. In areas with relatively soft soil or where piles are required to support artificial structures, a relatively large number of piles are driven into the soil. This driving causes noise pollution in the surrounding area. Furthermore, such driving exerts forces on the piles, which may weaken or damage them.

[0002] GB Patent Application Publication No. 1066247(A) describes a vibratory hammer for driving piles or other materials, which has two shafts with vertical and rotational motions, mounted on a support housing, and equipped with gears and disks. The gears and disks are engaged with weights, so that when the shafts rotate in opposite directions, they exert an oscillatory rotational moment on the support housing. This causes the support housing to rotate, and simultaneously, the striking members impact the anvil portion of the housing. This document is more relevant to drilling piles using rotational vibration (somewhat confusingly called torsion) around a horizontal axis. Furthermore, the rotation of each mass is coupled (see Figures 1 to 4) and occurs at the same frequency. U.S. Patent Application Publication No. 3583497A and Chinese Patent No. 110424384B provide further background art.

[0003] Recently, gentle driving of piles (GDP) has been developed using vibration. WO 2021 / 040523 A1 describes a shaker for this purpose. The shaker uses a combination of vertical and torsional vibration. Since ground vibration and noise are undesirable, it is advantageous to eliminate the vertical vibration. However, pure torsional excitation does not always reliably drive the pile to final penetration. Therefore, while shakers work well in many cases and situations, this is not always the case.

[0004] Accordingly, the present invention is directed to an improved pile and pile driver, as well as a method for driving piles, which overcomes one or more of the above-mentioned problems and shortcomings of the prior art without sacrificing functionality and advantages, and provides reliable results. [Summary of the Invention] The present invention aims to overcome one or more limitations of prior art piles, pile drivers, and methods for driving piles, or at least provide an alternative. Friction between a pile and the soil is typically considered to consist of two components: shaft resistance (along the sides of the pile) and tip resistance (under the pile). The first component is naturally minimized by torsional vibration and is therefore largely eliminated by shakers for gentle pile driving (GDP). The second component cannot be overcome by torsional excitation. In the present invention, tip resistance, in particular, is minimized by modifying the profile of the pile tip. Such pile profiling can be achieved in several ways. In a first aspect, the present invention relates to a monopile for support purposes for gentle driving into soil. The monopile is manufactured from a first material selected from concrete, metal such as steel, and combinations thereof, and includes a monopile tip driving resistance reducing portion. The tip resistance reducer is selected from a circumferential discontinuity, a circumferential continuous profile, a hardened coating, and combinations thereof. In particular, the monopile has a length of 5 m to 100 m and a diameter of 0.5 m to 20 m. This reduces the resistance when driving the monopile into the soil by typically 10% to 90%, in particular 20% to 50%, compared to a monopile without the resistance reducer. It has been found that by modifying the profile of the pile tip, the tip resistance can be minimized or at least reduced. Such pile profiling can be carried out in several ways. That is, by creating teeth of various shapes (discontinuous profile), by creating a smooth (continuous) profile (e.g., corrugated), by reducing the pile thickness at the tip (e.g., making the pile edges "sharper"), by applying a non-stick coating (where the term "non-stick" is used with reference to the surrounding soil) to prevent the soil from adhering to the pile tip, by applying a hardening coating to the pile tip, and any combination of the above. The appropriate modification is typically based on the pile dimensions on the one hand and the soil characteristics on the other hand.Depending on the type of soil, qualitatively different pile profiling can be applied. An additional advantage of the monopiles of the present invention is their improved driveability, allowing for rapid installation, thereby reducing the operating time of offshore construction vessels and significantly reducing the installation costs of wind parks. Furthermore, it has been found that the bearing strength of the monopiles of the present invention is determined primarily by the shaft resistance, with the tip having little influence. It should also be noted that conducting standard tests to measure the pile bearing strength can also be useful for determining the minimum allowable wall thickness and for ensuring that the tip geometry does not affect the final pile bearing strength.

[0005] In a second aspect, the present invention relates to a shaker (1) for gently driving a monopile. The shaker (1) comprises a fixture (9) for mechanically fixing a vibrator (3) to the monopile, at least one actuator (4), the vibrator (3) being configured to impart vertical vibrations to the monopile at a first vibration frequency and to impart torsion to the monopile at a second torsional frequency, a controller for driving the at least one actuator (4), and in particular a monopile according to the invention. The term "frequency" refers to 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 mode of operation.

[0006] In a third aspect, the present invention relates to a method for driving a monopile into soil, comprising providing a shaker (1) according to the present invention, mounting the shaker (1) on a monopile according to the present invention, and driving the monopile into soil.

[0007] In a fourth aspect, the present invention relates to a kit of parts comprising a shaker according to the invention, the kit of parts comprising at least one of a fixture (9), a vibrator (3), at least one actuator (4), a controller and a monopile according to the invention.

[0008] The present invention can also be considered to relate to a shaker that generates torsional vibrations about a vertical axis in combination with vertical vibrations. The torsional vibrations are typically performed at a much higher frequency than the vertical vibrations and are considered to continuously break down static friction between the pile and the surrounding soil. Once the bond between the pile and the surrounding soil is broken, the vertical vibrations drive the pile into the soil. In a first aspect, the present invention relates to a shaker for gently driving a pile. The shaker includes a fixture for mechanically fixing the vibrator to the pile, i.e., for transmitting vibration energy to the pile. The vibrator is adapted to impart vertical vibrations to the pile at a first vibration frequency and torsion to the pile at a second, typically much higher, torsional frequency. The vibrator includes at least two groups i≧2 of eccentric masses. Each group i includes at least two equal masses j. Each mass m i,j is the distance d from the vibrator i , typically spaced apart by distances parallel to the axis of rotation, such as distances d1 and d2. i,j has at least one horizontal axis i The vibrator includes at least one motor. The at least one motor is attached to a mass m i,j The horizontal axis ha i Rotate around the mass m of group i i,j The horizontal axis ha i along the same angular velocity ω i It is intended to rotate at an angular velocity ω i is the angular velocity ω i+1 Typically, the torsional frequency is higher than the vertical vibration frequency, typically several times higher. i+1,j is the horizontal axis ha i+1 along with an opposite angular velocity ω i+1 The vibrator includes a controller that controls the mass m of the group i to drive at least one motor. i,j The individual angular velocities ω iThe controllers are intended to control the total horizontal force exerted by each mass, to control the total vertical force exerted by each mass, and to balance the total vertical force exerted by each mass. In addition to these forces, gravity pulls the pile mass downward. Therefore, the controller can balance the force in the z-direction and control the resultant force in the x-direction (or equivalently, in the y-direction, or a combination of the x- and y-directions). Here, as in a Cartesian coordinate system, the z-direction is parallel to the pile axis, and the x- and y-directions are perpendicular to the pile axis. The shaker can drive the pile into the soil by a combination of torsional vibration, typically at a high frequency (or vibration mode, if the excitation is anharmonic), and vertical vibration, typically at a low frequency (or vibration mode, if the excitation is anharmonic). No additional driving means, such as a hammer device, is required. In this regard, the eccentric mass typically rotates at high speed. Typically, the masses are positioned to generate two opposing forces at certain locations, creating a torsional moment along the pile's longitudinal axis, but no force at other locations. The shaker and method of the present invention are faster and quieter. For example, for a medium-sized pile 10 m long and approximately 75 cm in diameter, the pile is driven approximately twice as fast as with conventional techniques. The pile can move downward at a speed of approximately 30 cm / sec. Furthermore, compared to impact hammers, there is little or no pile deformation. The energy generated by the shaker of the present invention is primarily used for driving the pile. Reference is made to International Publication No. 2021 / 040523 A1, the contents of which are incorporated by reference. The advantages of this specification are discussed in detail throughout this specification. [Detailed Description of the Invention] Typical dimensions and characteristics of a wind turbine are as follows:

[0009] DNV-OS-J101-2007: Design of offshore wind turbine structures DNV-RP-C203: Fatigue design of offshore steel structures Steel type: S355 Yield strength: 355MPa Elastic modulus E=210GPa Poisson's ratio ν=0.3 Linear thermal expansion coefficient (T≦100°C)α=12e-6 K-1 Partial Material Coefficients -Ultimate limit state strength check, γs=1.10 -ULS buckling check, γs=1.20 -Service limit state, γs=1.00 -Seismic ultimate limit state, γs=1.15 Model: REpower5M (5.0MW) Turbulence intensity class: IEC Ib / GL Offshore Type Class I Structural design life: 25 years Hub height: 85m above mean sea level Blade tip height: 153m above mean sea level Rotor diameter: 126m Wind area: 12,469m 2 Nacelle mass (without rotor): 290 tonnes (approximate) Rotor: 120 tons (approximate) Cut-in wind speed: 3.5m / s Rated wind speed: 13.0m / s Cut-out wind speed: 30m / s Operating rotor speed: 7.7 rpm to 12.1 rpm Nominal rotor speed: 10.5 rpm Structure type: steel pipe Tower Dimensions Base: D=6.00m, t=35mm Top: D=4.50m, t=20mm Initial mass estimate = π x 5.25 x 0.0275 x 70 x 7,850 = 250 t In an exemplary embodiment of the monopile of the present invention, the circumferential discontinuities are located along the length of the monopile. There may be between 1 and 10 circumferential discontinuities. Each circumferential discontinuity is individually between 0.5 cm and 50 cm high and between 0.5 cm and 50 cm long.

[0010] In an exemplary embodiment of the monopile of the present invention, the continuous circumferential profile is provided in the longitudinal direction of the monopile. There may be 1 to 10 continuous circumferential profiles. Each continuous circumferential profile has an individual height of 0.5 cm to 50 cm and a length of 0.5 cm to 50 cm.

[0011] In an exemplary embodiment of the monopile, the reduction in thickness of the monopile is between 0.1% and 50% of the diameter of the monopile.

[0012] In an exemplary embodiment of the monopile, the edge width of the sharp edge is between 0.2 cm and 10 cm.

[0013] In an exemplary embodiment of the monopile of the present invention, the hard coating is selected from alloys such as Si alloys, SiC, and the like.

[0014] In an exemplary embodiment of the monopile of the present invention, the monopile includes a second material that is embedded in the first material, the second material being selected from a polymer, a resin such as an epoxy resin, graphene, and carbon nanotubes.

[0015] The exemplary embodiment described above allows for reduced resistance when driving the monopile into the soil, as previously mentioned.

[0016] In an exemplary embodiment of the shaker, the vibrator comprises at least two groups i ≥ 2 of eccentric masses, each group i including at least two equal masses j. Each mass m i,j is the distance d from the center of rotation of the vibrator i The masses m on one side are spaced apart by i,1 is the mass m on the other side i,2 or mass m i,1 and mass m i,2 rotate in opposite directions. i,j has at least one horizontal axis iAt least one actuator (4) is attached to the mass m i,j , the corresponding horizontal axis ha i In this case, the mass m in group i is rotated around i,j are the same angular velocity ω i The horizontal axis ha i rotates around the mass m in group i+1 i+1,j is the angular velocity ω in the opposite direction i+1 The horizontal axis ha i+1 Rotates around the object with angular velocity ω i is the angular velocity ω i+1 The controller is different from the mass m of group i. i,j The individual angular velocities ω i , controlling the sum of the horizontal forces exerted by each mass, and balancing the sum of the vertical forces exerted by each mass.

[0017] In the shaker of the present invention, 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 for reciprocating motion. i,j and at least one horizontally oriented mass configured for reciprocating motion, for example at least one pair of at least two horizontally oriented identical masses configured for reciprocating motion, in particular a linear actuator, for example a linear piston hp i,j Each piston is configured to provide linear motion for a corresponding cylinder. At least two vertically oriented masses, e.g., linear pistons vp, are configured for reciprocating motion. i,j , the cylinder has a frequency ω vpi It operates at a vertical reciprocating velocity rv vi At least two horizontally oriented masses, e.g., linear piston cylinders, configured for reciprocating motion are individually configured to provide a frequency ω hpi It operates at a horizontal reciprocating speed of rh vjEach pair of cylinders is configured to move in opposite directions, for example, with a phase difference of 180 degrees. In each linear piston pair, each piston is located at a distance d from the center of rotation of the vibrator. i The masses are individually spaced apart by a distance ω. The reciprocating motion can be in a vertical or horizontal direction. The masses may be driven by an actuator, such as a piston, which pushes and retracts the masses, or a motor, such as an electric motor. Similarly, any pair of reciprocating masses can be used, such as cylinders. This provides a centrally located vertical cylinder. The vertical cylinder generates vertical vibrations (see arrows in Figure 4a). The amplitude can be adjusted by varying (typically by selecting) the stroke of the cylinder. The frequency ω can also be adjusted by varying (typically by controlling) the speed of the cylinder's movement. pi may be adjusted. In this way, frequency and amplitude remain independent of each other. In principle, more vertical cylinders may be used. If more vertical cylinders are used, they are arranged at least in pairs, or optionally all, equidistantly spaced from the center of the pile. The same applies to the horizontal cylinders. The horizontal cylinders are arranged tangentially to the pile being driven, i.e., horizontally. The strokes are synchronized, operating at the same frequency, but in opposite directions, e.g., 180 degrees out of phase. That is, when one moves in one direction, the other moves in the opposite direction (see green and red arrows; the colors indicate the difference between pushing and pulling). More cylinders may be arranged in the pile. They extend and retract in sync. The vertical cylinders (or pistons) and horizontal cylinders (or pistons) may operate at different frequencies, typically ω for any pair of horizontal and vertical cylinders. hpi ≠ω vpiArrays of cylinders may also be considered, where each set or pair (e.g., horizontal cylinders) may contain subsets operating at different frequencies (e.g., 50% of the cylinders operating at a higher frequency, 50% of the cylinders operating at a lower frequency, etc.). In this way, non-pure sinusoidal vibrations can be generated, and more complex forms of vibration can be generated if desired. Linear actuators may be selected from hydraulic cylinders, electric cylinders, pneumatic cylinders, and piezo stacks.

[0018] In an exemplary embodiment of the shaker of the present invention, the center of gravity of the shaker and the axis of rotation of the pile may be coincident, typically within a few percent, for example within 5%.

[0019] In an exemplary embodiment of the shaker of the present invention, the shaker is adapted to be driven by at least one actuator and has at least one mass m i,j , preferably with at least one gear adapted to rotate two masses in one group i, which allows good and simple force adaptation as well as force control when driving the pile. In one example, masses of different groups may be driven by the same gear.

[0020] In an exemplary embodiment of the shaker of the present invention, the first group comprises masses m 1,1 and mass m 1,2 and the second group may comprise masses m 2,1 and mass m 2,2 and any additional group may comprise masses m i,1 and mass m i,2 Thus, a wide variety of masses and numbers of groups may be employed. Typically, for simplicity of construction, only a limited number of groups, such as two, are used, although the invention is not limited in this respect.

[0021] In an exemplary embodiment of the shaker of the present invention, the controller may be adapted to control the cancellation of the sum of the vertical forces of the group. By varying the angular velocity, typically by carefully selecting and balancing the mass and the radius and / or distance, the sum of the vertical forces is cancelled. This results in a very stable mode of operation with a minimal amount of noise.

[0022] In exemplary embodiments of the shaker of the present invention, horizontal forces may be controlled to be additive. Like the vertical forces, horizontal forces can be controlled by varying angular velocity, typically by balancing mass and carefully selecting radius and / or distance.

[0023] Also, vertical forces may still occur, such as at low frequencies. In either case, the mass and gravity of the pile, combined with the torsion, drives the pile into the soil.

[0024] In an exemplary embodiment of the shaker of the present invention, in the i-th group, a first mass m i,1 is the first distance d from the side of the vibrator i A second mass m i,2 is the same first distance d from the side of the vibrator opposite the first mass i The masses in a group are typically located on "opposite sides" of each other relative to the position of the vibrator.

[0025] In an exemplary embodiment of the shaker of the present invention, at least one actuator has a horizontal axis of rotation ha i may be individually adapted to rotate at 10 Hz to 200 Hz (600 rpm to 12000 rpm), preferably 20 Hz to 180 Hz, more preferably 30 Hz to 150 Hz, even more preferably 40 Hz to 120 Hz, such as 50 Hz to 100 Hz, for example 60 Hz to 80 Hz.

[0026] In an exemplary embodiment of the shaker of the present invention, the at least one first actuator has a horizontal axis of rotation ha i may be individually adapted to rotate at a first vibration frequency of 10 Hz to 50 Hz (600 rpm to 3000 rpm), preferably 12 Hz to 30 Hz, more preferably 15 Hz to 25 Hz, for example 16 Hz to 24 Hz.

[0027] In an exemplary embodiment of the shaker of the present invention, the at least one second actuator has a horizontal axis of rotation ha i at a second torsional frequency of 15 Hz to 200 Hz (900 rpm to 12000 rpm), preferably 30 Hz to 150 Hz, more preferably 50 Hz to 100 Hz, for example 60 Hz to 80 Hz.

[0028] In one example, the first vibrational frequency may be 1400 rpm and the second torsional frequency may be 4800 rpm.

[0029] In an exemplary embodiment of the shaker of the present invention, at least one second angular torsional rate ω i is the first angular velocity ω i+1 and preferably at least one angular velocity ω i is the angular velocity ω i+1 is at least 4 times, more preferably at least 10 times, for example at least 50 times.

[0030] In an exemplary embodiment of the shaker of the present invention, mass m i,1 and mass m i,2 is the horizontal axis of rotation ha i Distance e from i and the masses m i+1,1 and mass m i+1,2 is the horizontal axis of rotation ha i+1 Distance e from i+1 The electrodes may be spaced apart by a distance of 100 mm.

[0031] In an exemplary embodiment of the shaker of the present invention, mass mi,j is a radius e i The center of gravity of the disk-shaped mass is the axis of rotation ha i and , respectively. This may provide a well-balanced mass.

[0032] In an exemplary embodiment of the shaker of the present invention, mass m i+1,1 / mass body m i,1 The ratio of e i / e i+1 This allows the forces of the i-th group and the i+1-th group to be balanced, typically to within 1%, e.g., perfectly balanced.

[0033] In an exemplary embodiment of the shaker of the present invention, the shaker comprises two mass groups, with horizontal rotation axes ha1 and ha2 spaced equal distances from the center point of the shaker, thereby balancing the forces of the i-th and i+1-th groups.

[0034] In an exemplary embodiment of the shaker of the present invention, the mass may be disk-shaped, as such masses are known to be easy to attach to a shaft.

[0035] In exemplary embodiments of the shaker of the present invention, the mass may be from 5 gr to 5000 gr, preferably from 10 gr to 1000 gr, for example from 30 gr to 600 gr, for example from 50 gr to 400 gr. For larger piles and / or heavier and / or stiffer soils, larger masses may be used. Additionally or alternatively, the angular velocity may be increased.

[0036] In an exemplary embodiment of the shaker of the present invention, the distance / radius e i is between 1 cm and 50 cm, preferably between 2 cm and 40 cm, for example between 3 cm and 30 cm.

[0037] In an exemplary embodiment of the shaker of the present invention, the controller may be, for example, F z1 =-Fz2 and at least one actuator may be driven in phase, for example to have exactly equal magnitude, typically within 1% accuracy.

[0038] In an exemplary embodiment of the shaker of the present invention, the shaker may include a receiving structure, such as a groove, which allows the pile to be securely attached to the vibrator of the present invention.

[0039] In an exemplary embodiment of a shaker of the present invention, the controller may be adapted to provide a vertical drive frequency of 10 Hz to 50 Hz.

[0040] In an exemplary embodiment of the shaker of the present invention, the shaker has at least one distance d i In particular, the shaker is configured to adjust all distances d i is configured to adjust

[0041] In an exemplary embodiment of the shaker of the present invention, the fixtures (9) are configured to secure the shaker to the outside of the monopile, to the inside of the monopile, across the edge of the monopile, or a combination thereof.

[0042] In an exemplary embodiment of the method of the present invention, the vibrator is calibrated before driving the pile into the soil, allowing for better control of driving force, angular velocity, soil properties, pile-soil interaction, etc.

[0043] The present invention will be further explained through the following examples, which are exemplary and explanatory and are not intended to limit the present invention. It will be apparent to those skilled in the art that many variations, whether obvious or not, fall within the scope of protection defined by the claims of the present invention. [Brief explanation of the drawings]

[0044] [Figure 1] Some details are shown. [Figure 2]Some details are shown. [Figure 3a] Some details are shown. [Figure 3b] Some details are shown. [Figure 3c] Some details are shown. [Figure 3d] Some details are shown. [Figure 4a] 10 shows an alternative embodiment with a piston. [Figure 4b] 10 shows an alternative embodiment with a piston. [Figure 4c] 10 shows an alternative embodiment with a piston. [Figure 4d] 10 shows an alternative embodiment with a piston. [Figure 4e] 10 shows an alternative embodiment with a piston. [Figure 4f] 10 shows an alternative embodiment with a piston. [Figure 4g] 10 shows an alternative embodiment with a piston. [Figure 5a] 1 shows an exemplary monopile. [Figure 5b] 1 shows an exemplary monopile. [Figure 6a] The experimental results are shown. [Figure 6b] The experimental results are shown. [Figure 6c] The experimental results are shown. DETAILED DESCRIPTION OF THE INVENTION

[0045] Figure 1 shows an example of a prototype shaker of the present invention mounted on a pile. The main block is machined to efficiently house the shaker's main components (actuators, gears, shafts, and masses) and ensure that the center of gravity of the masses is located at the desired position. The shaker includes an actuator that provides input energy. Three gears are used to transmit force from the actuator to two shafts. Each of the two shafts has two eccentric masses, for a total of four eccentric masses. When the masses begin to rotate, centrifugal force is generated, which is transmitted to the pile in the form of a torsional moment.

[0046] Figure 2 shows a top view of the shaker prototype, showing the relative spatial positions of the masses and the main distances (d1, d2, e1, e2) from the blocks. [Example] This paper details the design and functionality of a small-scale shaker, includes a description of how the shaker works, technical drawings outlining the shaker's mechanical components, a description of the electric actuator frequency control system, a parametric study of the forces and moments expected to be generated by the shaker, and includes safety recommendations and operating instructions.

[0047] The shaker is designed to be mounted on top of a small-scale pile, as shown in Figure 1. The shaker generates a force through counter-rotating masses located a specific distance from the center of rotation. This force, combined with another force of opposite sign, generates a moment. This moment is only effective with respect to the z-axis shown in Figure 1. This means that the moment is applied only when the masses are in the positions shown in Figure 1 and rotated 180 degrees relative to the depicted positions. This generates a harmonic torsional moment that is transmitted to the top of the pile. The system is driven by frequency-controlled electric actuators. It may also include a feedback loop that provides measurements of the actual force and / or angular rotation, compares the measurements with current values, and optionally corrects for the measured variations by, for example, increasing or decreasing the angular velocity. This can be done for the entire system or for a portion of the system, such as a group of masses i. Furthermore, the masses and their placement are variable, providing sufficient flexibility to generate the desired moment. Components were selected to ensure the shaker would function properly over a long period of time. Figure 3 below shows the technical details of the final prototype design of the shaker.

[0048] Force F exerted by a single rotating massz is cancelled at every angle θ by the force generated on the other axis moving in antiphase. Similarly, on the other part of the axis. F x In the case of F x cancel at all angles θ except for the maximum values ​​of 0 and 180 degrees. Considering that the two masses on one side are offset 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 shaker is to eliminate the moment generated about the x-axis when the masses are at 90 and 270 degrees relative to the origin (considered as the position shown in the diagram). Different eccentricities necessarily result in different masses. Considering that the axes are aligned with the x-axis, no moment about the y-axis is expected to be generated. Finally, the generation of forces and moments within the overall framework is shown in the figure below, using a specific case study as an example.

[0049] Figure 2 shows the shaker and lists the parameters under analysis. For the case study, the following values ​​were chosen: m1 = 10 gr, e1 = 5 cm, e2 = 8 cm, d1 = 10 cm, d2 = 15 cm, and m2 = m1e1 / e2 = 6.3 gr. Given that distances d1 and d2 must be different for space reasons, mass m2 was calculated to have zero resultant moment about the x-axis. As a result, the resolved forces in the x-axis add up, but the resolved forces in the z-axis cancel each other out, summing to zero.

[0050] Figures 3a through 3d show the components of this prototype shaker, along with their reference numbers. The role of each shaker component is described below. Component 27 corresponds to the engine, which provides power and moves the eccentric mass. Components 43 and 36 comprise the support plate and fixture for the engine, ensuring proper alignment of the engine shaft with the drive shaft gear 29. Clamp 35 prevents slippage between the engine shaft and the drive shaft. Gear trains 18 and 25 are used to transmit engine torque to shafts 2 and 22. A safety clamp is used on power gear 31 to ensure proper alignment between the gears. Clamp 26 is used to maintain the eccentric mass in place while the shaft is moving. In the side view, components 8 and 21 comprise the bearing and clamp, respectively.

[0051] Figure 3c shows a top view of the shaker. Part 32 consists of ball bearings to allow the engine shaft to rotate. Parts 33 and 34 consist of spacer rings to ensure that the parts of the power train are properly joined together.

[0052] Because the shaker actuator can reach high speeds, it is typically very important to take several safety precautions before starting the shaker. 1. Replaceable parts, such as additional masses and tightening bolts, must be prevented from flying off during operation. Furthermore, several protective measures should be in place, and personnel should not be allowed near the shaker during operation. 2. The simulated maximum force generated on the shaft by the shaker during operation is 400 N (per eccentric weight). Any deviation can cause slight bending of the shaft, making the shaker unstable and unpredictable. Therefore, it is preferable to use a disk-shaped mass whose center of gravity coincides with the axis of rotation, or two identical masses spaced equal distances from the axis. 3. The gear is fixed to the shaft by a set screw. A small piece of copper is sandwiched between the set screw and the shaft to prevent damage to the shaft. Care must be taken when removing the gear to prevent the copper piece from falling off. 4. The actuator shaft is fixed to the drive shaft with a clamping nut (MLN8). The specified tightening torque is 24.5 Nm. This allowed the lab-scale pile to be driven into the soil multiple times without any problems.

[0053] 4a to 4g show an alternative exemplary embodiment comprising two horizontally moving pistons 3 and one vertically moving piston 3. FIG.

[0054] Figures 5a-5b show exemplary monopiles, with a zigzag profile in Figure 5a and a wavy configuration in Figure 5b. It has been found that these monopiles can be driven into the soil 5% to 30% faster (in terms of time) compared to identical piles without such tip drag reducers. This is in addition to the advantages of the gentle driving (GDP) of the piles of the present invention over the prior art of the prior art.

[0055] Figures 6a and 6b show a sinusoidal input signal to the shaker, with larger amplitudes indicating a reactive torsional vibration signal (t) and smaller amplitudes indicating a vertical response (v).

[0056] Figure 6c shows the penetration depth as a function of time and applied force. In this figure, on the left side, the GDP of the present invention is shown, i.e., piles driven using the GDP technique. In these figures, the solid line represents a pile without a profile, the dashed line represents a pile with a wave profile, and the dash-dotted line represents a pile with a tooth tip profile. From this figure, it can be seen that the GDP shaker of the present invention has a significantly better performance than the prior art. It can also be seen that piles with a profile have an even better performance. [Explanation of symbols]

[0057] 1...Shaker, 2...Shaft, 3...Vibrator, 4...Actuator, 8...Bearing, 9...Fixture, 18...Gear, 21...Clamp, 22...Shaft, 25...Gear, 26...Clamp, 27...Engine, 29...Gear, 31...Safety clamp, 32...Ball bearing, 33...Spacer, 34...Spacer, 35...Clamp, 36...Support + Fixture, 43...Support + Fixture, d i …From the side of the vibrator to mass m i,j Distance to i, e i →Horizontal rotation axis ha i from mass m i,j Distance to i, ha i ...Horizontal axes i and m i,j ...mass body j, ω of group i I ...angular velocity i

Claims

1. A supporting monopile for gentle driving into the soil, comprising: The monopile is manufactured from a first material selected from concrete, metal such as iron, and combinations thereof, and is provided with a tip driving resistance reducing portion of the monopile, the tip resistance reducing portion being selected from a circumferential discontinuity, a circumferential continuous profile, a hardened coating, and combinations thereof.

2. 2. A monopile as described in claim 1, wherein the circumferential discontinuities are arranged in the longitudinal direction of the monopile, there are 1 to 10 circumferential discontinuities, and each of the circumferential discontinuities individually has a height of 0.5 cm to 50 cm and a length of 0.5 cm to 50 cm.

3. 2. A monopile as described in claim 1, wherein the continuous circumferential profile is arranged in the longitudinal direction of the monopile, there are 1 to 10 continuous circumferential profiles, and each of the continuous circumferential profiles individually has a height of 0.5 cm to 50 cm and a length of 0.5 cm to 50 cm.

4. 2. A monopile according to claim 1, wherein the hardened coating is selected from alloys such as Si alloys, SiC, and the like.

5. 10. The monopile of claim 1, wherein the monopile comprises a second material, the second material being embedded in the first material, the second material being selected from a polymer, a resin such as an epoxy resin, graphene, and carbon nanotubes.

6. A shaker (1) for gently driving monopiles, a fixture (9) for mechanically fixing the vibrator (3) to the monopile; At least one actuator (4); a vibrator (3) configured to impart vertical vibration to the monopile at a first vibration frequency and torsion to the monopile at a second torsional frequency; a controller for driving the at least one actuator (4), The vibrator at least one pair of at least two vertically oriented equal masses configured for reciprocating motion; at least one horizontally oriented mass configured for reciprocating motion; Equipped with a shaker.

7. 7. A shaker according to claim 6, The vibrator comprises at least one pair of at least two vertically oriented equal masses configured for reciprocating motion, the masses being selected from vertical linear actuators, and at least one pair of at least two horizontally oriented equal masses configured for reciprocating motion, the masses being selected from horizontal linear actuators, each pair of masses being configured for reciprocating motion.

8. 8. A shaker according to claim 7, The vertical linear actuator is a linear piston vp ｉ，ｊ and / or The horizontal linear actuator is a linear piston hp ｉ，ｊ and / or Each piston is configured to provide linear motion of a corresponding cylinder, and the cylinders of the at least two vertically oriented masses configured to reciprocate move at a vertical reciprocating velocity rv. ｖｉ The cylinders of the at least two horizontally oriented masses are individually configured to operate at a horizontal reciprocating velocity rh ｖｊ and each pair of cylinders are configured to move in opposite directions, and each piston is positioned at a distance d from the center of rotation of the vibrator. ｉ Shakers are spaced apart.

9. A shaker (1) according to claim 6, The at least one actuator (4) has a horizontal axis of rotation ha ｉ and / or the mass is between 5 gr and 5000 gr; and / or Distance / radius e ｉ is between 1 cm and 50 cm, and / or the controller drives the at least one actuator (4) in phase, and / or the shaker comprises a receiving structure; and / or the controller is configured to provide a vertical drive frequency of between 10 Hz and 50 Hz; and / or There are no additional drives, and / or The shaker, wherein the fasteners (9) are configured to fasten the shaker to the outside of the monopile, to the inside of the monopile, across the edge of the monopile, or a combination thereof.

10. 1. A method for driving a monopile into soil, comprising: Providing a shaker (1) according to any one of claims 6 to 9; Mounting the shaker (1) on a monopile according to any one of claims 1 to 5; driving the monopile into the soil.

11. 11. The method of claim 10, wherein the vibrator is calibrated before driving the monopile into the soil.

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

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