Test device and test method for offshore wind power suction tube foundation simulation

Abstract

The invention relates to the technical field of offshore wind power, and discloses a test device and a test method for offshore wind power suction tube foundation simulation. The test device comprises a suction cylinder provided with a first through hole and a second through hole; the simulation box contains a soil body and water and is used for simulating an installation environment; the vertical loading device is mounted at the top of the simulation box, is connected with the suction barrel and is used for lowering the suction barrel to a preset position of the soil body; the grouting device is communicated with the first through hole and is used for grouting the suction barrel; the sinking device is communicated with the second through hole and is used for pumping water from the suction barrel or injecting water into the suction barrel; and the monitoring device is arranged in the simulation box and is used for monitoring the strength of the soil body and the height of a water film in the suction barrel. Therefore, the simulation of the whole life cycle use process of the suction barrel from installation, service and recovery can be realized.

Description

Technical Field

[0001] The present application relates to the field of offshore wind power technology, for example, to a test device and a test method for simulating an offshore wind power suction tube foundation. Background Art

[0002] The suction cylinder foundation has the advantages of low manufacturing cost, high bearing capacity, and recyclability. The penetration process of the suction cylinder foundation is divided into two stages, namely the self-weight penetration stage and the subsequent negative pressure penetration stage. In the self-weight penetration stage, the suction cylinder foundation gradually penetrates into the seabed at a constant speed under its own buoyant weight and the load of the crane. When the buoyant weight of the suction cylinder foundation is equal to the sum of the end resistance and side friction resistance of the cylinder penetrating into the seabed, the process ends. The water in the cylinder is pumped out of the cylinder to generate a pressure difference, and the suction cylinder further penetrates into the seabed to a certain depth. Subsequently, grouting is carried out in the cylinder to ensure that the cylinder top cover is fully fitted with the seabed soil. After the service life, the suction cylinder is recovered by positive pressure.

[0003] At present, there have been many experimental studies on the negative pressure installation and cyclic loading of suction cylinders, but there is still a lack of simulation research on the entire life cycle of suction cylinders from installation, service to recycling.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0005] In order to provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not an extensive review, nor is it intended to identify key / critical elements or delineate the scope of protection of these embodiments, but rather serves as a prelude to the detailed description that follows.

[0006] The embodiments of the present disclosure provide a test device and a test method for simulating the foundation of an offshore wind turbine suction cylinder, so as to simulate the use process of the suction cylinder throughout its life cycle.

[0007] In some embodiments, a test device for simulating the foundation of an offshore wind power suction cylinder includes: a suction cylinder, provided with a first through hole and a second through hole; a simulation box, filled with soil and water, for simulating the installation environment; a vertical loading device, installed on the top of the simulation box and connected to the suction cylinder, for lowering the suction cylinder to a preset position of the soil; a grouting device, connected to the first through hole, for grouting the suction cylinder; a sinking device, connected to the second through hole, for pumping water from the suction cylinder or injecting water into the suction cylinder; a monitoring device, arranged in the simulation box, for monitoring the strength of the soil and the height of the water film in the suction cylinder.

[0008] In some embodiments, the grouting device includes: a grouting pump, including a first motor, and the frequency of which can be controlled and adjusted; a slurry outlet pipe, the first end of which is connected to the outlet of the slurry outlet pump, and the second end of which is connected to the first through hole; a pressure sensor, which is arranged in the first through hole to monitor the pressure in the suction cylinder in real time; and a flow sensor, which is arranged in the slurry outlet pipe to measure the slurry flow in real time.

[0009] In some embodiments, the monitoring device includes: a spherical detector, arranged in the suction cylinder to record cone tip resistance and pore pressure data; an image acquisition module, arranged in the water to capture images of the soil and water film height in the suction cylinder.

[0010] In some embodiments, the suction cylinder includes: a cylinder body, which is surrounded by a cylinder wall and a cylinder cover; wherein the first through hole and the second through hole are arranged in the cylinder cover; a diffusion plate, which is arranged in the cylinder body and has a preset distance between it and the cylinder cover; wherein the diffusion plate is evenly provided with multiple hydrophobic holes, so that the water injected by the sinking device can be flexibly and evenly released into the cylinder body after passing through the hydrophobic holes.

[0011] In some embodiments, the vertical loading device includes: a first sliding unit, which is arranged at the top of the simulation box and can slide along a first direction; a second sliding unit, which is arranged at the top of the first sliding unit and can slide along a second direction; wherein the second direction and the first direction are two different directions on the horizontal plane; a base unit, which is arranged at the top of the second sliding unit; and a loading unit, which is arranged at the base unit and connected to the suction cylinder.

[0012] In some embodiments, the sinking device includes: a water pump, including a second motor, and the frequency can be controlled and adjusted; a water pipe, the first end of which is connected to the outlet of the water pump, and the second end is connected to the second through hole; a flow detector, which is arranged at the outlet of the water pump to monitor the pumping speed / injection speed of the water pump in real time.

[0013] In some embodiments, the test method for simulating the foundation of an offshore wind power suction cylinder is applicable to a test device for simulating the foundation of an offshore wind power suction cylinder as described above; the test method for simulating the foundation of an offshore wind power suction cylinder includes: controlling the vertical loading device to start, so that the suction cylinder is penetrated into the soil to a first preset depth; controlling the sinking device to pump water, so that the suction cylinder continues to penetrate the soil to a second preset depth; controlling the grouting device to inject grout into the suction cylinder, and stopping grouting when slurry overflows from the second through hole of the suction cylinder; after the slurry in the suction cylinder is completely solidified, controlling the vertical loading device to apply a cyclic load to the suction cylinder; controlling the sinking device to inject water into the suction cylinder to generate positive pressure in the suction cylinder, and controlling the vertical loading device to pull up the suction cylinder; when the pressure in the suction cylinder no longer rises, controlling the vertical loading device to stop pulling up, and completing the recovery of the suction cylinder.

[0014] In some embodiments, the control of the sinking device to pump water includes: making a first correction to the initial pumping speed according to the penetration resistance of the suction cylinder in the process of penetrating the first preset depth or the strength of the soil; making a second correction to the pumping speed after the first correction according to the uplift height of the soil in the suction cylinder and the actual penetration depth of the suction cylinder, so that the uplift speed of the soil in the suction cylinder is less than a speed threshold; or, the control of the grouting device to grout into the suction cylinder includes: determining an initial grouting speed according to the strength of the soil; making a first correction to the initial grouting speed according to the pumping speed during the penetration of the suction cylinder; making a second correction to the pumping speed after the first correction according to the fluidity of the slurry The grouting speed after the correction is corrected for the second time; the grouting speed after the second correction is corrected for the third time according to the disturbance of the soil; or, after the slurry in the suction cylinder is completely solidified, the vertical loading device is controlled to apply a cyclic load to the suction cylinder, including: after the slurry in the suction cylinder is completely solidified for a first preset time, the vertical loading device is controlled to apply a cyclic load of a first preset frequency to the suction cylinder; when the first preset frequency cyclic load loading is completed, the vertical loading device is controlled to maintain the load on the suction cylinder, so that the soil at the bottom of the suction cylinder is consolidated for a second preset time; the vertical loading device is controlled to apply a cyclic load of a second preset frequency to the suction cylinder.

[0015] In some embodiments, the controlling of the sinking device to inject water into the suction cylinder includes: determining an initial water injection rate according to the soil strength in the suction cylinder; correcting the initial water injection rate once according to the grouting rate during the grouting process; correcting the water injection rate after the first correction twice according to the attenuation amplitude of the first-stage resistance value, the increase amplitude of the second-stage resistance value, and the attenuation amplitude of the third-stage resistance value of the suction cylinder; wherein the first-stage resistance value is the resistance value borne by the suction cylinder when the first preset frequency cyclic load is applied to the suction cylinder; the second-stage resistance value is the resistance value borne by the suction cylinder after the soil at the bottom of the suction cylinder is consolidated; the third-stage resistance value is the resistance value borne by the suction cylinder when the second preset frequency cyclic load is applied to the suction cylinder; when injecting water, the water injection rate after the second correction is corrected three times according to the disturbance of the soil in the suction cylinder or when the turbidity level in the suction cylinder reaches a preset level.

[0016] In some embodiments, a spherical detector is used to detect the soil condition in the suction cylinder; the disturbance condition of the soil is determined by: obtaining the calibration coefficient of the spherical detector and the detected real-time resistance / pressure; determining the initial strength of the soil based on the calibration coefficient and the real-time resistance / pressure; and correcting the initial strength based on a first correction coefficient, a second correction coefficient, and a third correction coefficient to obtain a final soil strength.

[0017] The test device and test method for simulating an offshore wind turbine suction cylinder foundation provided by the embodiments of the present disclosure can achieve the following technical effects: The vertical loading device is installed on the top of the simulation box and is connected to the suction cylinder. It can provide a downward or upward load to the suction cylinder, thereby allowing the suction cylinder to penetrate into the soil or pull up the suction cylinder. The grouting device is connected to the suction cylinder through the first through hole and can inject grout into the suction cylinder. The sinking device is connected to the suction cylinder through the second through hole, and can pump water from the suction cylinder to facilitate the suction cylinder to penetrate into a deeper position and subsequent grouting. It can also inject water into the suction cylinder to cooperate with the vertical loading device to pull up the suction cylinder. The monitoring device is set in the simulation box and can monitor the strength of the soil so as to adjust the speed of pumping / grouting / water injection in real time and reduce the disturbance to the soil during the pumping / grouting / water injection stages. The monitoring device can also monitor the height of the water film in the suction cylinder to determine whether the water injection requirements are met. In this way, from the gravity penetration and negative pressure penetration of the suction cylinder, to grouting in the cylinder, cyclic loading, slurry solidification, and then to the recovery of the suction cylinder, the simulation of the entire life cycle of the suction cylinder from installation, service and recovery is realized, providing a test basis for the actual use of the suction cylinder.

[0018] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily described by corresponding drawings. These exemplary descriptions and drawings do not limit the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not constitute a scale limitation. In addition, Figure 1 This is a schematic structural diagram of a test device for simulating an offshore wind power suction cylinder foundation provided by an embodiment of the present disclosure; Figure 2 This is a structural diagram of a suction cylinder provided by an embodiment of the present disclosure from one perspective; Figure 3 is a structural schematic diagram of the suction cylinder provided by an embodiment of the present disclosure from another perspective; Figure 4 is a schematic structural diagram of a grouting device provided in an embodiment of the present disclosure; Figure 5 is a structural schematic diagram of a diffuser plate provided in an embodiment of the present disclosure; Figure 6 is a schematic diagram of the three-dimensional structure of the first sliding unit, the second sliding unit and the bottom plate unit provided in an embodiment of the present disclosure; Figure 7 is a top view of a first sliding unit, a second sliding unit, and a bottom plate unit provided in an embodiment of the present disclosure; Figure 8 is a front view of a first sliding unit, a second sliding unit, and a bottom plate unit provided by an embodiment of the present disclosure; Figure 9 is a structural diagram of a loading unit provided in an embodiment of the present disclosure; Figure 10 It is a structural schematic diagram of a sinking device provided by an embodiment of the present disclosure; Figure 11 is a schematic structural diagram of a simulation box provided by an embodiment of the present disclosure; Figure 12 Schematic diagram of a test method for simulating an offshore wind turbine suction cylinder foundation provided by an embodiment of the present disclosure; Figure 13 is a schematic diagram of a method for controlling water pumping of a submersible device provided by an embodiment of the present disclosure; Figure 14 is a schematic diagram of a method for controlling a grouting device to grout into a suction cylinder provided by an embodiment of the present disclosure; Figure 15is a schematic diagram of a method for controlling a vertical loading device to apply a cyclic load to a suction cylinder, provided by an embodiment of the present disclosure; Figure 16 It is a schematic diagram of a method for controlling a sinking device to inject water into a suction cylinder provided in an embodiment of the present disclosure.

[0020] Reference numerals: 10. Suction cylinder; 11. First through hole; 12. Second through hole; 13. Cylinder body; 131. Cylinder wall; 132. Cylinder cover; 14. Diffuser plate; 141. Drain hole; 15. Third through hole; 20. Simulation chamber; 21. Side panel; 22. Bottom panel; 23. Tempered glass; 24. Drain pipe; 30. Vertical loading device; 31. First sliding unit; 311. First reaction frame; 312. First support plate; 313. First slide rail; 314. First slider; 32. Second sliding unit; 321. Second reaction frame; 322. Second support plate; 323. Second slide rail; 324. Second slider; 33. Base plate unit; 331. Base plate; 332. Third reaction frame; 34. Loading unit; 341. Servo motor; 342. Electric cylinder; 343. Loading arm; 344. Inner push rod; 345. Through hole; 346. Tension and pressure sensor; 347. Fixing ring; 348. Ring fastener; 349. Limit rod; 350. Limit hole; 40. Grouting device; 41. Grouting pump; 42. Grouting pipe; 43. Pressure sensor; 44. Flow sensor; 50. Sinking device; 51. Water pump; 52. Water pipe; 53. Flow detector; 60. Controller; 70. External support. DETAILED DESCRIPTION

[0021] In order to be able to understand the features and technical content of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. The accompanying drawings are for reference only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the sake of convenience of explanation, a full understanding of the disclosed embodiments is provided through multiple details. However, one or more embodiments can still be implemented without these details. In other cases, to simplify the drawings, well-known structures and devices can be simplified for display.

[0022] In the description and claims of the embodiments of the present disclosure, as well as in the accompanying drawings, the terms "first," "second," and the like are used to distinguish similar items and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate to describe the embodiments of the present disclosure herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions.

[0023] In the embodiments of the present disclosure, the terms "upper", "lower", "inside", "middle", "outside", "front", "back" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are mainly intended to better describe the embodiments of the present disclosure and their embodiments, and are not intended to limit the indicated devices, elements or components to having a specific direction, or to be constructed and operated in a specific direction. Moreover, in addition to being used to indicate directions or positional relationships, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain dependency or connection relationship in certain circumstances. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0024] Furthermore, the terms "disposed," "connected," and "fixed" should be interpreted broadly. For example, "connected" can mean a fixed connection, a removable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediary, or an internal connection between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the embodiments of this disclosure based on the specific circumstances.

[0025] Unless otherwise stated, the term "plurality" means two or more.

[0026] In the embodiment of the present disclosure, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B means: A or B.

[0027] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0028] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other.

[0029] Combine Figure 1 As shown, the embodiment of the present disclosure provides a test device for simulating the foundation of an offshore wind power suction cylinder, which includes: a suction cylinder 10, a simulation box 20, a vertical loading device 30, a grouting device 40, a sinking device 50 and a monitoring device. Figure 2 and Figure 3 As shown, the suction cylinder 10 is provided with a first through hole 11 and a second through hole 12. Grouting can be injected into the suction cylinder 10 through the first through hole 11, and water in the suction cylinder 10 can be extracted or injected into the suction cylinder 10 through the second through hole 12. The simulation box 20 is a box with an open top, which contains soil and water and is used to simulate the installation environment of the suction cylinder 10. The vertical loading device 30 is installed on the top of the simulation box 20, and the loading end is connected to the suction cylinder 10, which is used to apply a load to the suction cylinder 10 and lower the suction cylinder 10 to a preset position of the soil. The grouting device 40 is connected to the first through hole 11 to inject slurry into the suction cylinder 10. The sinking device 50 is connected to the second through hole 12, which is used to extract water from the suction cylinder 10 or inject water into the suction cylinder 10. The monitoring device is installed in the simulation box 20 to monitor the strength of the soil to determine the disturbance of the soil during the grouting, pumping and water injection stages. The monitoring device can also monitor the height of the water film in the suction cylinder 10 to determine whether the water injection requirements are met.

[0030] During the simulation, first control the vertical loading device 30 to apply a downward load to the suction cylinder 10, and lower the suction cylinder 10 to the appropriate position. Then control the sinking device 50 to start, pump out the water in the suction cylinder 10, and make the suction cylinder 10 penetrate deeper into the soil. Subsequently, control the grouting device 40 to start, and inject grouting into the suction cylinder 10. After the grouting is completed, wait for the slurry to solidify. After the slurry solidifies, control the vertical loading device 30 to apply a cyclic load to the suction cylinder 10 to consolidate the soil at the bottom of the suction cylinder 10. Then control the sinking device 50 to start again, inject water into the suction cylinder 10, and generate positive pressure in the suction cylinder 10. At the same time, control the vertical loading device 30 to start, and provide an upward load to the suction cylinder 10. In this way, under the action of the positive pressure inside the suction cylinder 10 and the vertical loading device 30, the suction cylinder 10 is pulled up. When the pressure in the suction cylinder 10 stops rising, indicating that the suction cylinder 10 has been pulled out, the vertical loading device 30 is controlled to stop, thereby completing the recovery of the suction cylinder 10 .

[0031] Using the test device for simulating the offshore wind power suction cylinder foundation provided by the embodiment of the present disclosure, the vertical loading device 30 is installed on the top of the simulation box 20 and is connected to the suction cylinder 10. It can provide a downward or upward load to the suction cylinder 10, thereby allowing the suction cylinder 10 to penetrate into the soil or pull up the suction cylinder 10. The grouting device 40 is connected to the suction cylinder 10 through the first through hole 11 and can inject grout into the suction cylinder 10. The sinking device 50 is connected to the suction cylinder 10 through the second through hole 12. It can pump water from the suction cylinder 10 to facilitate the penetration of the suction cylinder 10 into a deeper position and subsequent grouting. It can also inject water into the suction cylinder 10 to cooperate with the vertical loading device 30 to pull up the suction cylinder 10. The monitoring device is arranged in the simulation box 20 and can monitor the strength of the soil so as to adjust the speed of pumping / grouting / water injection in real time and reduce the disturbance to the soil during the pumping / grouting / water injection stages. The monitoring device can also monitor the water film height within the suction cylinder 10 to determine whether the water injection requirements have been met. This simulation of the entire life cycle of the suction cylinder 10, from installation, service, and recovery, is achieved, from gravity penetration and negative pressure penetration of the suction cylinder 10, to grouting, cyclic loading, slurry curing, and finally recovery of the suction cylinder 10. This provides a test basis for the actual use of the suction cylinder 10.

[0032] Optionally, the controller 60 is in communication with the vertical loading device 30 , the grouting device 40 , the sinking device 50 and the monitoring device, and is used to receive data monitored by the monitoring device and control the start and stop of the vertical loading device 30 , the grouting device 40 and the sinking device 50 .

[0033] Optionally, combined Figure 4 As shown, the grouting device 40 includes: a grouting pump 41, a slurry outlet pipe 42, a pressure sensor 43 and a flow sensor 44. The grouting pump 41 includes a first motor, and the controller 60 is connected to the first motor in communication to control the frequency of the first motor, thereby controlling the grouting speed. The first end of the slurry outlet pipe 42 is connected to the outlet of the grouting pump 41, and the second end is connected to the first through hole 11. The pressure sensor 43 is arranged in the first through hole 11 and is connected to the controller 60 in communication, and is used to detect the pressure of the suction cylinder 10 in real time and send the pressure to the controller 60. The flow sensor 44 is arranged in the slurry outlet pipe 42 and is connected to the controller 60 in communication, and is used to monitor the slurry flow in real time and send the slurry flow to the controller 60. The controller 60 can control the frequency of the first motor according to the received pressure and slurry flow of the suction cylinder 10, thereby achieving refined control of grouting and reducing the disturbance of grouting to the soil in the suction cylinder 10.

[0034] Optionally, the grouting pump 41 is a single screw pump, and the flow rate of the single screw pump is generally 0.1 m 3 / h to 0.5 m 3 / h, the inlet and outlet diameters are 25 mm, and are connected to the special hose for screw air compressors with an inner diameter of 25 mm through an annular fastener.

[0035] Optionally, the first through hole 11 is a steel threaded interface that can be connected to a 25 mm pipe.

[0036] Slurries typically consist of cement, with some bentonite replacing the cement. Slurries are typically described by the percentage of bentonite. For example, a 20% bentonite slurry would have a mass ratio of bentonite to (bentonite + cement) of 20%. A 0% bentonite slurry represents pure cement, while a 100% bentonite slurry is entirely bentonite.

[0037] Optionally, the monitoring device includes a spherical probe and an image acquisition module. The spherical probe is installed within the suction cylinder 10 and records the cone tip resistance and pore pressure data (derived from a pore pressure sensor mounted on the cylinder cover 132) in real time as the suction cylinder 10 is inserted and withdrawn. The spherical probe communicates with the controller 60 via a data acquisition device, transmitting the recorded data to the controller 60. Based on the received cone tip resistance and pore pressure data, the controller 60 determines the soil mass and, in turn, the soil disturbance.

[0038] The image acquisition module is disposed in the water and is communicatively connected to the controller 60. It is used to capture images of the soil and water film height within the suction cylinder 10 and transmit the images to the controller 60. Suitably, the suction cylinder 10 is made of a transparent acrylic material to facilitate the image acquisition module to capture images. Optionally, the image acquisition device includes: a camera, a base, and a support frame. The camera is fixed to the simulation box 20 via the support frame, which allows the underwater camera to move in three degrees of freedom to adjust the optimal shooting angle. The support frame is composed of two mutually perpendicular steel pipes. The horizontal steel pipe is mounted on the model box, and the upper and lower parts of the vertical steel pipe are connected to the horizontal steel pipe and the base via screws, respectively. By unscrewing the upper screw, the vertical steel pipe can be moved on the horizontal steel pipe. By unscrewing the lower screw, the camera can be moved vertically along the steel pipe. The camera is disposed on the base and rotates up and down via the screw at the connection with the base.

[0039] Optionally, see again Figure 2 、 Figure 3 and Figure 5The suction cylinder 10 includes a cylinder body 13 and a diffuser plate 14. The cylinder body 13 is surrounded by a cylinder wall 131 and a cylinder cover 132. The first through hole 11 and the second through hole 12 are provided on the cylinder cover 132. The outer diameter of the diffuser plate 14 is equal to the inner diameter of the cylinder body 13. Optionally, the diffuser plate 14 is made of stainless steel with a thickness of 5 mm and a diameter of 100 mm. The diffuser plate 14 is arranged horizontally within the cylinder body 13 and maintains a preset distance from the cylinder cover 132. Optionally, the preset distance is 30 mm. In this way, the diffuser plate 14 separates the interior of the suction cylinder 10 into a buffer chamber, namely the space between the cylinder cover 132 and the diffuser plate 14. The diffuser plate 14 is provided with a plurality of hydrophobic holes 141, which are evenly arranged in multiple circles along the surface of the diffuser plate 14. Optionally, the hydrophobic holes 141 are circular holes with a diameter of 1 mm, and the number of hydrophobic holes 141 is 50 to 100. When the sinking device 50 injects water into the suction cylinder 10, the water first enters the buffer chamber and then flows downward through the drain holes 141. The small-diameter drain holes 141 release the water evenly and flexibly, preventing strong jets from directly impacting the soil inside the cylinder and effectively reducing the impact disturbance caused by the water injection on the soil inside the cylinder.

[0040] Optionally, the cylinder body 13 is made of organic glass, with an outer diameter of 300 mm and a wall thickness of 10 mm, and the cylinder cover 132 is 40 mm thick.

[0041] Optionally, the second through-hole 12 is equipped with a silicone film and filter screen, and the wall of the cylinder 13 is provided with a graduated scale. During testing, the scale allows the penetration depth of the suction cylinder 10 into the soil and the thickness of the water film to be observed. The second through-hole 12 is a pagoda-shaped steel interface that accepts a 6 mm inner diameter pipe. To prevent soil from entering the cylinder and flowmeter during negative pressure pumping, a steel filter screen is installed below the second through-hole 12.

[0042] Optionally, valves are installed on the first through hole 11 and the second through hole 12, which can be opened and closed independently. A third through hole 15 is opened above the cylinder cover 132 for installing a borehole pressure sensor.

[0043] Optionally, combined Figures 6 to 9As shown, the vertical loading device 30 includes a first sliding unit 31, a second sliding unit 32, a base unit 33, and a loading unit 34. The first sliding unit 31 is disposed on the top of the simulation box 20 and is capable of sliding in a first direction. The second sliding unit 32 is disposed on the top of the first sliding unit 31 and is capable of sliding in a second direction. The first direction and the second direction are two different directions on the horizontal plane. For example, the first direction is the left-right direction, and the second direction is the front-back direction. Alternatively, the first direction is the front-back direction, and the second direction is the left-right direction. The base unit 33 is disposed on the top of the second sliding unit 32 and is used to carry the loading unit 34. The loading unit 34 is disposed on the base unit 33, and its loading end is connected to the top of the suction cylinder 10. In this way, by controlling the first sliding unit 31 and the second sliding unit 32 to slide in their respective directions, the suction cylinder 10 can be moved together by the loading unit 34, thereby moving the suction cylinder 10 to a suitable position. The loading unit 34 can then be controlled to lower the suction cylinder 10 into the soil. In this way, the suction cylinder 10 can be placed at any position in the soil.

[0044] Optionally, see again Figures 6 to 8 The first sliding unit 31 includes two first reaction frames 311 and two first support plates 312. The two first reaction frames 311 are fixedly mounted on opposite sides of the top of the simulation box 20 along a first direction by bolts. Each first reaction frame 311 is fixedly mounted with a first slide rail 313 along its length by screws. The bottoms of the two first support plates 312 are fixedly mounted with a first slider 314 along their length (also the length of the first reaction frame 311) by screws. The two first slide rails 313 are slidably embedded in the two first sliders 314. The second sliding unit 32 is mounted on the two first support plates 312. In this way, the cooperation between the first slide rails 313 and the first slider 314 can drive the loading unit 34 to move along the first direction. Optionally, the length of the first reaction frame 311 is 1705 mm. The length of the first slide rail 313 is 1660 mm and is made of steel. The height of the first slider 314 is 22 mm. The first support plate 312 is 620 mm long, 106 mm wide, and 9 mm thick.

[0045] Optionally, see again Figures 6 to 8The second sliding unit 32 includes two second reaction frames 321 and two second support plates 322. The two second reaction frames 321 are arranged side by side on top of the first sliding unit 31. Specifically, the two second reaction frames 321 are arranged side by side along the second direction, and the two ends of the second reaction frames 321 are fixed to the top of the two first support plates 312 via screws. Each second reaction frame 321 is provided with a second slide rail 323 along its length. The bottom of each second support plate 322 is provided with a second slider 324 along its length (which is also the length of the second reaction frame 321). The two second slide rails 323 are slidably embedded in the two second sliders 324. The base plate unit 33 is provided on the two second support plates 322. In this way, the cooperation between the second slide rails 323 and the second slider 324 can drive the loading unit 34 to move in the second direction. Optionally, the length of the second reaction frame 321 is 1705 mm. The distance between the two second reaction frames 321 is 460 mm. The second slide rail 323 is 1660 mm long and made of steel. The second slider 324 is 22 mm high. The second support plate 322 is 620 mm long, 106 mm wide, and 9 mm thick.

[0046] Optionally, see again Figures 6 to 8 The base plate unit 33 includes: a base plate 331 and two third reaction frames 332. The two third reaction frames 332 are arranged on the top of the second sliding unit 32. Specifically, the two third reaction frames 332 are arranged side by side along the first direction, and the two ends of the third reaction frames 332 are respectively fixed to the top of the two second support plates 322 by screws. The base plate 331 is fixed to the top of the two third reaction frames 332 by screws. The loading unit 34 is arranged on the base plate 331. Optionally, the length of the second reaction frame 321 is 645 mm. The distance between the two third reaction frames 332 is 460 mm.

[0047] Optionally, see again Figure 9 The loading unit 34 includes a servo motor 341, an electric cylinder 342, and a loading arm 343. The electric cylinder 342 is connected to the servo motor 341 and can be driven by the servo motor 341 to push down and pull up, driving the lower structure to move up and down, with a maximum push-down height of 430 mm. The electric cylinder 342 is installed on the bottom plate 331 of the bottom plate unit 33. In order to facilitate the movement of the inner push rod 344 of the electric cylinder 342, see Figure 6 and Figure 7The bottom plate 331 is provided with a through hole 345, and the inner push rod 344 is passed through the through hole 345. The bottom of the inner push rod 344 is connected to the top of the loading arm 343 through the tension and pressure sensor 346. The bottom of the loading arm 343 is connected to the suction cylinder 10. In this way, the servo motor 341 transmits power to the electric cylinder 342, thereby driving the inner push rod 344 to move up and down, and the inner push rod 344 then drives the suction cylinder 10 to move up and down through the loading arm 343. The loading unit 34 can ensure multiple controls on the vertical static load, vertical cyclic load, and vertical displacement of the suction cylinder 10.

[0048] Optionally, continue with Figure 9 The loading unit 34 also includes a fixing ring 347 and an annular fastener 348. The top of the fixing ring 347 is connected to the bottom of the loading arm 343. The inner wall of the fixing ring 347 is adhered to the side wall of the cylinder cover 132 of the suction cylinder 10 through a silicone film, increasing the friction between the fixing ring 347 and the suction cylinder 10. The annular fastener 348 is sleeved on the outside of the fixing ring 347. Tightening the screw on the annular fastener 348 can further strengthen the connection between the fixing ring 347 and the suction cylinder 10.

[0049] Optionally, the loading unit 34 further includes a limiting rod 349. Figure 6 and Figure 7 The bottom plate unit 33 is provided with a limiting hole 350, and a limiting rod 349 is provided through the limiting hole 350 and connected to the fixing ring 347. In this way, the limiting rod 349 limits the horizontal deviation and flipping of the fixing ring 347 and the suction cylinder 10. Specifically, the limiting hole 350 is provided on the bottom plate 331.

[0050] Optionally, combined Figure 10 As shown, the sinking device 50 includes: a water pump 51, a water pipe 52 and a flow detector 53. The water pump 51 includes a second motor, and the controller 60 is connected to the second motor in communication to control the frequency of the second motor, thereby controlling the pumping speed / injection speed. The first end of the water pipe 52 is connected to the outlet of the water pump 51, and the second end is connected to the second through hole 12. The flow detector 53 is arranged at the outlet of the water pump 51, and is used to detect the pumping rate / injection rate of the water pump 51 in real time, and send the pumping rate / injection rate to the controller 60. The controller 60 can control the frequency of the second motor according to the received injection rate / pumping rate to reduce the disturbance of the soil in the suction cylinder 10 caused by pumping / injection.

[0051] The water pump 51 draws water from the suction cylinder 10, creating a pressure differential between the inside and outside of the cylinder, and lowering the suction cylinder 10 into the soil. The adjustable frequency range of the water pump 51 is generally 800 Hz to 3000 Hz, corresponding to a second motor speed of 800 rpm to 3000 rpm. At different frequencies, the open flow rate of the water pump 51 ranges from 1.5 L / min to 6 L / min. The inlet and outlet of the water pump 51 are connected to a 6 mm inner diameter silicone hose (water pipe 52) via a hose clamp. The silicone hose connected to the outlet of the water pump 51 is connected to a flow meter 53 via a hose clamp to ensure a tight seal at the interface. The flow meter 53 visualizes the pumping / injection rate of the water pump 51 and ultimately calculates the pumped water volume.

[0052] Optionally, combined Figure 11 As shown, the simulation box 20 is surrounded by four side panels 21 and a bottom panel 22. The length, width and height of the side panels 21 and the bottom panel 22 are all 1500 mm, the thickness is 10 mm, and the material is PVC. One side panel 21 is provided with a rounded rectangular mounting hole 150 mm away from the bottom panel, 1150 mm long and 1230 mm high. Double-layer tempered glass 23 is installed in the mounting hole, and a scale is provided on the tempered glass 23. Combined with the tempered glass 23 and the scale, the soil and water level in the simulation box 20 and the situation in the suction cylinder 10 can be observed in real time. The bottom of each of the four side panels 21 is provided with a plurality of drainage holes with a diameter of 25 mm, and the center distance between two adjacent drainage holes is 500 mm. The drainage holes are connected to the external PVC drainage pipes 24 through threads, and each drainage pipe 24 can be independently controlled to open and close.

[0053] Optionally, the outside of the simulation box 20 is wrapped with an external bracket 70 made of a square steel pipe. The cross-section of the external bracket 70 is a square with a side length of 40 mm, which can support and protect the simulation box 20 and prevent excessive deformation when soil is added or loaded into the simulation box 20.

[0054] Based on the above-mentioned test device for simulating offshore wind turbine suction tube foundation, combined with Figure 12 As shown, the embodiment of the present disclosure provides a test method for simulating an offshore wind turbine suction tube foundation, comprising: S101, controlling the vertical loading device to start, and penetrating the suction cylinder into the soil to a first preset depth; S102, controlling the sinking device to pump water so that the suction cylinder continues to penetrate the soil to a second preset depth; S103, controlling the grouting device to inject grout into the suction cylinder, and stopping the grouting when grout overflows from the second through hole of the suction cylinder; S104, after the slurry in the suction cylinder is completely solidified, controlling the vertical loading device to apply a cyclic load to the suction cylinder; S105, controlling the sinking device to inject water into the suction cylinder to generate positive pressure in the suction cylinder, and controlling the vertical loading device to pull the suction cylinder upward; S106, when the pressure in the suction cylinder no longer increases, the vertical loading device is controlled to stop pulling up, thereby completing the recovery of the suction cylinder.

[0055] First, keeping both the first and second through-holes of the suction cylinder open, control the vertical loading device to lower the suction cylinder into the soil at a rate of approximately 0.2 mm / s using static pressure. Using the underwater camera, if the soil in the simulation chamber becomes turbid, it indicates that the suction cylinder wall has begun to penetrate the soil, disturbing it. At this point, the vertical loading device continues to control the suction cylinder to penetrate an additional 2 cm, bringing it to the first preset depth. This ensures a closed space within the cylinder, sufficient to create a pressure differential between the inside and outside of the suction cylinder during negative pressure pumping.

[0056] Next, the control unit activates the sinking mechanism and pumps water into the suction cylinder, causing it to penetrate under negative pressure. When the suction cylinder reaches the second preset depth in the soil, the cylinder is installed. Ensure a 2 cm or 4 cm film of water between the cylinder cover and the soil surface inside the cylinder.

[0057] Then, the grouting device is controlled to start, and the grouting pump is used to pump water to moisten the pipe, and the water in the pipe is discharged after the pipe is moistened. Connect the grouting pipe to the first through hole. Control the grouting device to start, and grout into the suction cylinder. The first through hole connection hose discharges the water film displaced by the injected slurry into the measuring cylinder. Optionally, the grouting pressure is generally less than or equal to 10 kPa, and the grouting is slowly injected into the cylinder to avoid excessive grouting pressure that lifts the suction cylinder or impacts and disturbs the soil in the cylinder. When the second through hole starts to discharge water, the time is counted and the volume change of the water in the measuring cylinder is recorded. When slurry overflows from the second through hole, the grouting is deemed to be completed, and the valve and grouting pump of the second through hole are closed to stop grouting. Disconnect the slurry outlet pipe from the suction cylinder, clean the grouting pump and the slurry outlet pipe, and measure the volume of the water film finally displaced.

[0058] Then, wait for the slurry in the suction cylinder to solidify. After the slurry has solidified, control the vertical loading device to start and apply cyclic loading to the suction cylinder to consolidate the soil at the bottom of the suction cylinder. Optionally, control the vertical loading device to apply multiple rounds of cyclic loading to the suction cylinder.

[0059] Then, the valve of the second through hole is controlled to open, the sinking device is controlled to start and water is injected into the suction cylinder to generate positive pressure in the suction cylinder. At the same time, the vertical loading device is controlled to pull up the suction cylinder with a fixed load of 500N.

[0060] Finally, when the pore pressure of the second through hole no longer rises, the vertical loading device is switched to a displacement null value, the upward pulling is stopped, and the recovery of the suction cylinder is completed.

[0061] Optionally, combined Figure 13 As shown, S102, controlling the submersible device to pump water, includes: S112, correcting the initial pumping speed based on the penetration resistance or soil strength during the process of the suction cylinder penetrating the first preset depth; S122 , performing a secondary correction on the pumping speed after the primary correction according to the uplift height of the soil in the suction cylinder and the actual penetration depth of the suction cylinder, so that the uplift speed of the soil in the suction cylinder is less than a speed threshold.

[0062] While the vertical loading device applies force to the suction cylinder to penetrate it to the first preset depth (to create a confined space and prepare for subsequent negative pressure penetration), the tension and pressure sensors provide feedback on the suction cylinder's penetration resistance. Simultaneously, a spherical detector located within the suction cylinder detects the soil strength within the cylinder. The controller detects the penetration resistance or soil strength and then makes a correction to the initial pumping speed. Optionally, the initial pumping speed can be pre-set based on experience. Optionally, the motor frequency corresponding to the initial pumping speed is 800 Hz. Optionally, when the penetration resistance exceeds a resistance threshold or the soil strength exceeds a first strength threshold, the initial pumping speed is corrected. Specifically, the motor frequency corresponding to the pumping speed is corrected to be greater than the first frequency. Optionally, the resistance threshold is 200 N, the first strength threshold is 10 kPa, and the first frequency is 2000 Hz. This increases the pumping speed, ensuring a sufficiently high negative pressure to maintain the suction cylinder's speed and ensure continuous penetration.

[0063] When water is subsequently pumped out (during negative pressure penetration), the soil in the suction cylinder will inevitably bulge due to the effect of negative pressure. The faster the water is pumped, the higher the bulge. The controller obtains the bulge height of the soil in the suction cylinder through the camera, and obtains the actual penetration depth of the suction cylinder. The penetration depth of the suction cylinder is the displacement of the loading arm. Then, based on the soil bulge speed and the actual penetration speed, the pumping speed after the first correction is corrected for the second time, so that the bulge speed of the soil in the suction cylinder is less than the speed threshold. Optionally, the speed threshold is 1 cm / minute. For example, the ratio of the soil bulge height h to the actual penetration depth L of the suction cylinder is calculated. When h / L is greater than the ratio threshold, the pumping speed is corrected to reduce the penetration speed of the suction cylinder, so that the bulge speed of the soil in the suction cylinder is less than the speed threshold. Optionally, the ratio threshold is 0.1.

[0064] In this way, the first correction to the initial pumping speed can avoid soil disturbance caused by excessive pumping. The second correction to the initial pumping speed ensures that the soil uplift speed is less than the speed threshold, thereby minimizing soil disturbance.

[0065] Optionally, combined Figure 14As shown, S103, controlling the grouting device to inject grout into the suction cylinder, including: S113, determining the initial grouting speed according to the strength of the soil; S123, correcting the initial grouting speed according to the pumping speed during the suction cylinder penetration process; S133, performing a second correction on the grouting speed after the first correction according to the fluidity of the slurry; S143, performing a third correction on the grouting speed after the second correction according to the disturbance of the soil.

[0066] The controller uses a spherical detector to obtain the soil strength within the suction cylinder and then determines the initial grouting rate based on the soil strength. Optionally, when the soil strength is greater than a second strength threshold, the soil is relatively hard, can withstand higher grouting pressures and grouting rates, and is less susceptible to disturbance. In this case, the initial grouting rate is the first rate. When the soil strength is less than or equal to the second strength threshold, the initial grouting rate is the second rate. Optionally, the second strength threshold is 10 kPa. The first rate is (100 ± 20) mL / min, and the second rate is less than 60 mL / min.

[0067] Subsequently, the initial grouting speed is corrected based on the actual pumping speed measured during the negative pressure penetration of the suction cylinder. Grouting is equivalent to the reverse process of pumping. Grouting can easily push up the suction cylinder, so it is necessary to grout slowly so that the water has enough time to drain out. During the entire penetration process of the suction cylinder, the pumping speed varies according to the changes in soil strength. Therefore, it is necessary to ensure that the actual grouting speed is less than or equal to 1 / 5 of the maximum pumping speed measured during the penetration process to avoid the grouting speed being too fast and pushing up the suction cylinder.

[0068] The grouting rate, which has undergone the primary correction, is then subjected to a secondary correction based on the slurry's fluidity. Optionally, the slurry's fluidity can be pre-measured through a fluidity test. Once the slurry's fluidity is determined, the required grouting pressure can be determined, and the rate can then be corrected.

[0069] Finally, the controller obtains an image of the soil in the suction cylinder through a camera, analyzes the image, and determines whether the soil is disturbed by the injected slurry. If the soil is disturbed, for example, if the soil is flushed out of a pothole by the slurry, the grouting speed after the second correction is corrected three times. Specifically, a degree threshold is pre-set to define the degree of disturbance of the soil. If the degree of soil disturbance is greater than or equal to the degree threshold, the greater the degree of soil disturbance, the greater the degree of negative correction of the grouting speed, that is, the more the grouting speed is reduced. If the degree of soil disturbance is less than the degree threshold, the current grouting speed is maintained unchanged.

[0070] Thus, the initial grouting rate is first determined based on the soil strength within the suction cylinder to avoid impacting the soil due to excessive grouting speed. The initial grouting rate is then corrected based on the pumping speed during the suction cylinder's penetration process, ensuring that the pumping speed is less than or equal to 1 / 5 of the maximum pumping speed measured during the penetration process to prevent the suction cylinder from being lifted due to excessive grouting speed. A second correction is then made to the initial pumping speed to reduce the disturbance of the soil caused by the slurry's fluidity. A third correction is made to the initial pumping speed to ensure that the disturbance of the soil caused by grouting is minimized.

[0071] Optionally, combined Figure 15 As shown, S104, after the slurry in the suction cylinder is completely solidified, the vertical loading device is controlled to apply a cyclic load to the suction cylinder, including: S114, after the slurry in the suction cylinder has been solidified for a first preset time, controlling the vertical loading device to apply a cyclic load of a first preset frequency to the suction cylinder; S124, when the first preset frequency cyclic load loading is completed, controlling the vertical loading device to maintain the load on the suction cylinder so that the soil at the bottom of the suction cylinder is consolidated for a second preset time period; S134, controlling the vertical loading device to apply a cyclic load of a second preset frequency to the suction cylinder.

[0072] After the grouting is completed, wait for the first preset time to allow the slurry to solidify. Optionally, the first preset time is 24 hours. Then, keep the first through hole and the second through hole of the suction cylinder closed, control the vertical loading device to start, push the suction cylinder downward, and apply a first preset frequency cyclic load. Optionally, the first preset frequency load is greater than or equal to 10,000 times. After the first preset frequency load is loaded, maintain the load so that the soil at the bottom of the suction cylinder consolidates for a second preset time. Optionally, the second preset time is greater than or equal to 7 days. After the second preset time, continue to control the vertical loading device to apply a second preset frequency cyclic load to the suction cylinder. Optionally, the second preset frequency cyclic load is greater than or equal to 10,000 times. In this way, the slurry and the soil at the bottom of the suction cylinder are made stronger.

[0073] Optionally, combined Figure 16 As shown, S105, controlling the sinking device to inject water into the suction cylinder includes: S115, determining an initial water injection rate based on the soil strength in the suction cylinder; S125, correcting the initial water injection rate according to the grouting rate during the grouting process; S135, performing a secondary correction on the water injection rate after the primary correction based on the attenuation amplitude of the first-stage resistance value experienced by the suction cylinder, the increase amplitude of the second-stage resistance value, and the attenuation amplitude of the third-stage resistance value; wherein the first-stage resistance value is the resistance value experienced by the suction cylinder when a cyclic load of a first preset frequency is applied to the suction cylinder; the second-stage resistance value is the resistance value experienced by the suction cylinder after the soil at the bottom of the suction cylinder is consolidated; and the third-stage resistance value is the resistance value experienced by the suction cylinder when a cyclic load of a second preset frequency is applied to the suction cylinder; S145 , during water injection, the water injection rate after the second correction is corrected three times according to the disturbance of the soil in the suction cylinder or when the turbidity in the suction cylinder reaches a preset level.

[0074] The controller obtains the soil strength in the suction cylinder through a spherical detector, and then determines the initial water injection speed based on the soil strength. Subsequently, the initial water injection speed is corrected according to the grouting speed. Here, the grouting speed refers to the maximum grouting speed during the grouting process. Grouting needs to be slow, but when recovering the suction cylinder by water injection, water needs to be injected quickly, otherwise the suction cylinder cannot be lifted up. After grouting, the slurry will block the second through hole to a certain extent, so a higher speed is required when injecting water. Optionally, the water injection speed is greater than or equal to 10 times the grouting speed, and less than or equal to 5 times the pumping speed, to avoid the suction cylinder rising too fast and inconsistent with actual usage.

[0075] During the period when the vertical loading device is controlled to apply a cyclic load to the suction cylinder, the resistance value that the suction cylinder bears is divided into three stages. The resistance value of the first stage is: the resistance value that the suction cylinder bears when the first preset frequency cyclic load is applied to the suction cylinder. At this time, the more severe the soil disturbance is, the greater the attenuation of the resistance value will be. The resistance value of the second stage is: the resistance value that the suction cylinder bears after the soil at the bottom of the suction cylinder is consolidated. During the consolidation process, the soil strength will recover and the resistance value will increase. The resistance value of the third stage is: the resistance value that the suction cylinder bears when the second preset frequency cyclic load is applied to the suction cylinder. At this time, the more severe the soil disturbance is, the greater the attenuation of the resistance value will be. Among them, the resistance value is detected by a tension and pressure sensor. Therefore, the attenuation amplitude of the resistance value in the first stage, the increase amplitude of the resistance value in the second stage, and the attenuation amplitude of the resistance value in the third stage are combined to make a secondary correction to the water injection rate after the first correction.

[0076] During the water injection process, the controller obtains images of the soil and water in the suction cylinder through a camera, analyzes the images, and then determines whether the soil is disturbed by the injected slurry. If the soil is disturbed, for example, the soil is flushed out of a pothole by the slurry, the grouting speed after the second correction is corrected three times. Specifically, a degree threshold is pre-set to define the degree of soil disturbance. If the degree of soil disturbance is greater than or equal to the degree threshold, the greater the degree of soil disturbance, the greater the negative correction degree of the water injection speed, that is, the more the water injection speed is reduced. If the degree of soil disturbance is less than the degree threshold, the current water injection speed remains unchanged. Alternatively, if the turbidity level in the suction cylinder reaches a preset level, the greater the degree of soil disturbance, the greater the negative correction degree of the water injection speed, that is, the more the water injection speed is reduced. If the turbidity level in the suction cylinder is less than the preset level, the current water injection speed remains unchanged.

[0077] In this way, the initial water injection rate is first determined based on the soil strength within the suction cylinder to avoid soil impact caused by excessively fast injection. The initial water injection rate is then corrected based on the grouting rate to ensure sufficient water pressure to lift the suction cylinder. The soil strength is then reflected by the three levels of resistance experienced by the suction cylinder, leading to a second correction to the initial pumping rate to minimize soil disturbance. This third correction to the initial water injection rate ensures that soil disturbance caused by water injection is minimized.

[0078] Optionally, the disturbance of the soil is determined by: Obtain the calibration coefficient of the ball detector and the detected real-time resistance / pressure; Determine the initial strength of the soil based on the calibration coefficient and real-time resistance / pressure; The initial strength is corrected according to the first correction coefficient, the second correction coefficient and the third correction coefficient to obtain the final soil strength.

[0079] The controller retrieves the calibration coefficients of the ball probe pre-stored in memory and uses the real-time resistance / pressure measured by the ball probe during the suction cylinder's penetration of the soil. The soil strength is used to characterize the disturbance. The initial strength of the soil is determined based on the real-time resistance / pressure measured using the calibration coefficients. This initial strength is then corrected using the first, second, and third correction coefficients to obtain the final soil strength.

[0080] Specifically, according to the formula Calculate the final soil strength. S is the final soil strength, F The real-time resistance / pressure detected by the probe of the ball detector. N is the calibration factor of the spherical detector, fcyc is the first correction coefficient, f con is the second correction coefficient, f post The first correction coefficient, the second correction coefficient and the third correction coefficient can be preset or obtained by calculation.

[0081] In this way, by correcting the initial strength of the soil through the correction coefficient, a more accurate soil strength can be obtained, and the disturbance of the soil can be judged more accurately.

[0082] Optionally, when a first preset cyclic load is applied to the suction cylinder, the ratio of the resistance value experienced by the suction cylinder during the final loading to the resistance value experienced by the suction cylinder during the first loading is determined as a first correction coefficient. Taking the example of a vertical loading device applying 10,000 cyclic loads to the suction cylinder (10,000 times the first preset frequency load and 10,000 times the second preset frequency load), for a total of 20,000 cyclic loads, the first correction coefficient is determined by dividing the resistance value experienced by the suction cylinder during the 10,000th loading by the resistance value experienced during the first loading (the percentage of resistance reduction). The first correction coefficient indirectly reflects the reduction in the strength of the surrounding soil when the suction cylinder is subjected to the first cyclic load.

[0083] Optionally, the second correction coefficient is determined by dividing the resistance value experienced by the suction cylinder during the first loading after soil consolidation by the resistance value experienced during the last loading before soil consolidation. Taking the example of a vertical loading device applying 10,000 cyclic loading cycles to the suction cylinder (10,000 at the first preset frequency and 10,000 at the second preset frequency), for a total of 20,000 cyclic loading cycles, the second correction coefficient is determined by dividing the resistance value experienced by the suction cylinder during the 10,001st loading cycle (the first loading cycle after soil consolidation) by the resistance value experienced during the 10,000th loading cycle (the last loading cycle before soil consolidation). The second correction coefficient indirectly reflects the extent of soil strength recovery during consolidation.

[0084] Optionally, when a second preset cyclic load is applied to the suction cylinder, the ratio of the resistance value experienced by the suction cylinder during the last loading to the resistance value experienced by the suction cylinder during the first loading is determined as a third correction coefficient. Taking the example of a vertical loading device applying 10,000 cyclic loads to the suction cylinder (the first preset frequency load is 10,000 times, and the second preset frequency load is 10,000 times), for a total of 20,000 cyclic loads, the third correction coefficient is determined by dividing the resistance value experienced by the suction cylinder during the 20,000th loading (the 10,000th loading after soil consolidation) by the resistance value experienced during the 10,001st loading (the first loading after soil consolidation). The third correction coefficient indirectly reflects the reduction in strength of the soil when subjected to the cyclic load again.

[0085] The above description and the accompanying drawings sufficiently illustrate the embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The embodiments represent only possible variations. Unless expressly required, individual components and functions are optional, and the order of operations may vary. Portions and features of some embodiments may be included in or replace portions and features of other embodiments. The embodiments of the present disclosure are not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A test device for simulating offshore wind turbine suction cylinder foundation, characterized in that: include: The suction cylinder is provided with a first through hole and a second through hole; Simulation box, filled with soil and water, used to simulate the installation environment; A vertical loading device, installed on the top of the simulation box and connected to the suction cylinder, used to lower the suction cylinder to a preset position on the soil; a grouting device, connected to the first through hole, for grouting the suction cylinder; a sinking device, connected to the second through hole, and used for pumping water from the suction cylinder or injecting water into the suction cylinder; A monitoring device is arranged in the simulation box and is used to monitor the strength of the soil and the height of the water film in the suction cylinder.

2. A test device for simulating offshore wind power suction cylinder foundation according to claim 1, characterized in that: The grouting device comprises: A grouting pump comprising a first motor and capable of controlling and adjusting frequency; a slurry discharge pipe, a first end of which is connected to the outlet of the slurry discharge pump, and a second end of which is connected to the first through hole; A pressure sensor is provided in the first through hole to monitor the pressure in the suction cylinder in real time; A flow sensor is provided on the slurry outlet pipe to measure the slurry flow in real time.

3. The test device for simulating offshore wind power suction cylinder foundation according to claim 1, characterized in that: The monitoring device comprises: A spherical detector is placed in the suction cylinder to record the cone tip resistance and pore pressure data; The image acquisition module is arranged in the water to acquire images of the soil and water film height in the suction cylinder.

4. The test device for simulating offshore wind power suction cylinder foundation according to claim 1, characterized in that: The suction cylinder comprises: The cylinder body is formed by a cylinder wall and a cylinder cover; wherein the first through hole and the second through hole are provided in the cylinder cover; A diffusion plate is arranged in the cylinder and has a preset distance between it and the cylinder cover; wherein the diffusion plate is evenly provided with a plurality of hydrophobic holes so that the water injected by the sinking device can be flexibly and evenly released into the cylinder after passing through the hydrophobic holes.

5. A test device for simulating offshore wind turbine suction cylinder foundation according to any one of claims 1 to 4, characterized in that: The vertical loading device comprises: a first sliding unit, disposed on the top of the simulation box and capable of sliding along a first direction; a second sliding unit, disposed on top of the first sliding unit and capable of sliding along a second direction; wherein the second direction and the first direction are two different directions on a horizontal plane; a bottom plate unit, arranged on the top of the second sliding unit; The loading unit is arranged on the base plate unit and connected to the suction cylinder.

6. A test device for simulating offshore wind turbine suction cylinder foundation according to any one of claims 1 to 4, characterized in that: The sinking device comprises: A water pump including a second motor and capable of controlling and adjusting the frequency; a water pipe, a first end of which is connected to the outlet of the water pump, and a second end of which is connected to the second through hole; A flow detector is provided at the outlet of the water pump to monitor the pumping speed / injection speed of the water pump in real time.

7. A test method for simulating offshore wind turbine suction tube foundation, characterized in that: A test device for simulating an offshore wind turbine suction cylinder foundation according to any one of claims 1 to 6; a test method for simulating an offshore wind turbine suction cylinder foundation comprising: Controlling the vertical loading device to start, and allowing the suction cylinder to penetrate the soil to a first preset depth; Controlling the sinking device to pump water so that the suction cylinder continues to penetrate the soil to a second preset depth; controlling the grouting device to inject grout into the suction cylinder, and stopping the grouting when grout overflows from the second through hole of the suction cylinder; After the slurry in the suction cylinder is completely solidified, controlling the vertical loading device to apply a cyclic load to the suction cylinder; Controlling the sinking device to inject water into the suction cylinder to generate positive pressure in the suction cylinder, and controlling the vertical loading device to pull up the suction cylinder; When the pressure in the suction cylinder no longer increases, the vertical loading device is controlled to stop pulling up, thereby completing the recovery of the suction cylinder.

8. A test method for simulating offshore wind turbine suction cylinder foundation according to claim 7, characterized in that: The control of the sinking device pumping water includes: Correcting the initial pumping speed according to the penetration resistance of the suction cylinder or the strength of the soil during the process of penetrating the first preset depth; According to the uplift height of the soil in the suction cylinder and the actual penetration depth of the suction cylinder, the pumping speed after the primary correction is corrected for a secondary time, so that the uplift speed of the soil in the suction cylinder is less than a speed threshold; or, The controlled grouting device injects grout into the suction cylinder, comprising: Determining the initial grouting speed according to the strength of the soil; According to the pumping speed during the penetration of the suction cylinder, the initial grouting speed is corrected once; According to the fluidity of the slurry, the grouting speed after the first correction is corrected for the second time; According to the disturbance of the soil, the grouting speed after the second correction is corrected three times; or, After the slurry in the suction cylinder is completely solidified, controlling the vertical loading device to apply a cyclic load to the suction cylinder includes: After the slurry in the suction cylinder has been solidified for a first preset time, controlling the vertical loading device to apply a cyclic load of a first preset frequency to the suction cylinder; When the first preset frequency cyclic load loading is completed, controlling the vertical loading device to maintain the load on the suction cylinder so that the soil at the bottom of the suction cylinder is consolidated for a second preset time period; The vertical loading device is controlled to apply a cyclic load of a second preset frequency to the suction cylinder.

9. A test method for simulating an offshore wind turbine suction cylinder foundation according to claim 8, characterized in that: The controlling the sinking device to inject water into the suction cylinder comprises: determining an initial water injection rate according to the soil strength in the suction cylinder; According to the grouting speed during the grouting process, the initial water injection speed is corrected once; The water injection rate after the primary correction is corrected for the second time according to the attenuation amplitude of the first-stage resistance value, the increase amplitude of the second-stage resistance value, and the attenuation amplitude of the third-stage resistance value experienced by the suction cylinder; wherein the first-stage resistance value is the resistance value experienced by the suction cylinder when the first preset frequency cyclic load is applied to the suction cylinder; the second-stage resistance value is the resistance value experienced by the suction cylinder after the soil at the bottom of the suction cylinder is consolidated; and the third-stage resistance value is the resistance value experienced by the suction cylinder when the second preset frequency cyclic load is applied to the suction cylinder; During water injection, the water injection speed after the second correction is corrected three times according to the disturbance of the soil in the suction cylinder or when the turbidity in the suction cylinder reaches a preset level.

10. A test method for simulating offshore wind turbine suction cylinder foundation according to claim 9, characterized in that: The soil condition in the suction cylinder is detected using a spherical detector; the disturbance condition of the soil is determined by: Obtaining a calibration coefficient of the spherical detector and a detected real-time resistance / pressure; determining the initial strength of the soil according to the calibration coefficient and the real-time resistance / pressure; The initial strength is corrected according to the first correction coefficient, the second correction coefficient and the third correction coefficient to obtain the final soil strength.

Images