Offshore wind turbine foundation scour depth monitoring device and installation method

Abstract

The present invention relates to a device for monitoring the scour depth of an offshore wind turbine foundation, comprising an operation and maintenance platform and a monitoring component; the operation and maintenance platform and the monitoring component are both connected to the side wall of the wind turbine foundation, the operation and maintenance platform is located above the monitoring component, the lower end of the wind turbine foundation is inserted below the mud line, the monitoring component is located below the sea level, and the operation and maintenance platform is located above the sea level; the operation and maintenance platform is connected to the monitoring component via a sling. The operation and maintenance platform is an annular hollow mesh bracket, which is fixedly connected to the side wall of the wind turbine foundation. The monitoring component includes an inflatable bag, an inner ring, an outer ring, multiple supports and a monitor; the present invention has the characteristics of being simple and convenient, accurate in monitoring, real-time dynamic monitoring of the entire process, and recyclable, and the corresponding installation method improves the efficiency of monitoring the scour depth and the three-dimensional morphology of the scour pit.

Description

Technical Field

[0001] The invention relates to an offshore wind turbine foundation scour depth monitoring device and an installation method. Background Art

[0002] As we strive for comprehensive modernization, while conventional energy still accounts for a significant portion of my country's energy mix, the proportion of renewable energy is increasing rapidly year by year. Offshore wind power, as a green, efficient, and reusable renewable energy source, is being widely used in both near and far waters.

[0003] Offshore wind turbine foundations are categorized into fixed and floating types. Both types directly or indirectly utilize the marine soil to maximize the bearing capacity of the wind turbine foundation. The presence of a wind turbine foundation alters the initial flow field in the surrounding area. Under the influence of waves and tidal currents, the soil surrounding the wind turbine foundation will scour, forming scour pits. The presence of scour pits can affect the stability of the wind turbine foundation. As the scour depth increases, the bearing capacity of the wind turbine foundation decreases significantly, further impacting the safety of the wind turbine above it. Existing wind turbine foundation scour depth monitoring mainly relies on topographic survey vessels to image the scour pit morphology and monitor the scour depth in three dimensions. However, the depth and morphology of scour pits change dynamically with changes in the ocean current environment. This installation method is not only expensive to monitor but also incapable of long-term dynamic monitoring. Therefore, a low-cost, long-term, and highly accurate wind turbine foundation scour depth monitoring method is urgently needed to more accurately assess the bearing capacity loss and increased deformation caused by scour.

[0004] Currently, non-contact scour installation methods are commonly used to image the three-dimensional scour pit morphology and monitor scour depth in offshore wind turbine foundations. While these methods can accurately monitor scour depth and three-dimensional scour pit morphology, they cannot monitor the foundation throughout its entire service life and transmit data in a timely manner. Furthermore, the monitoring process primarily relies on renting a topographic survey vessel and using the onboard monitoring equipment to image scour depth and scour pit morphology. This not only fails to achieve real-time dynamic monitoring but is also expensive.

[0005] For imaging the three-dimensional scour pit morphology and monitoring the scour depth of offshore wind turbine foundations, a contact-type scour installation method is also used. First, although contact monitoring can achieve periodic scour depth monitoring, it is achieved by installing components around the foundation. The installed components and the wind turbine foundation are welded together, which increases the installation resistance of the foundation and makes the installation process difficult. Secondly, because it is fixed around the bottom of the foundation, it is very difficult to repair when the monitoring component fails. Thirdly, because it indirectly derives the scour depth by monitoring changes in soil pressure and water pressure, and does not derive the scour depth by differentiating multiple sensors, it is easily affected by the complex marine environment, resulting in inaccurate measured data. Finally, it uses limited sensors to monitor the scour depth of local feature points and cannot monitor the morphology of three-dimensional scour pits.

[0006] Patent CN 106917420 A - A pile foundation scour monitoring device. This invention proposes a pile foundation scour monitoring device, including an underwater measuring tube, a measuring assembly, and a data acquisition instrument. By monitoring the real-time changes in the soil pressure on the pile side at different depths near the pile foundation and throughout the scour process, the influence of the scour depth on the pile foundation stress is obtained. By analyzing the non-periodic changes in the soil pressure on the pile side under wave and current scour, the stress state between the pile and the soil and the scour safety margin are obtained in real time. Although it is easy to operate, has high accuracy, good real-time performance, and effectively realizes remote monitoring of pile foundation scour, it can only obtain the scour depth during the foundation service process, and cannot obtain the three-dimensional dynamic scour pit morphology.

[0007] Patent 201810721314.9 - Bridge pier scour monitoring platform, this invention: discloses a bridge pier scour monitoring platform, including a sleeve, a pulley, an adjusting hammer, an ultrasonic sensor, an ascending limit card and a descending limit card. The above components are all located inside the sleeve, and the sleeve is fixedly installed by a steel wire rope installed around the bridge pier. One end of the pulley is connected to the adjusting hammer, and the other end is connected to the ultrasonic sensor. The adjusting hammer rises accordingly with the rising tide level, and the ultrasonic sensor descends. When the adjusting hammer reaches the ascending limit card, the sensor is completely submerged in the water and begins measuring; conversely, when the tide level drops, the ultrasonic sensor rises and leaves the water surface. The complete set of devices of the present invention can be installed above the water surface, avoiding the need for underwater installation in traditional methods, reducing the difficulty of sensor installation engineering; at the same time, the sensor is only submerged in water at high tide level, which reduces the immersion time, slows down the growth rate of organisms on the sensor surface, improves the accuracy of measurement data, and extends the maintenance time of the instrument. However, it can only measure the local scour depth in the scour pit through the sensor. The locally monitored scour depth cannot reflect the overall scour depth around the foundation, and cannot monitor the three-dimensional dynamic scour pit morphology.

[0008] Patent CN 113551829 A - Scour Monitoring Device and Offshore Wind Turbine Foundation Scour Installation Method. This invention: Through the provision of a fixed housing, multiple monitoring components can be driven into the seabed along with the offshore wind turbine pile foundation, making contact with the seabed. This contact-type scour monitoring device is less susceptible to environmental influences, provides more accurate monitoring data, and offers excellent monitoring stability, preventing measurement errors under strong scour conditions. However, since it is fixed around the foundation, it increases installation resistance, making the installation process difficult, and can also cause damage during the driving process.

[0009] Patent 202210597562.3 - A Lifting Foundation Scour Monitoring Device and Method. This invention discloses a lifting foundation scour monitoring device comprising: a lifting screw mounted on the sidewall of a bridge pier, a sliding seat threadedly connected to the lifting screw, a sealing cover mounted on the sliding seat, a monitoring assembly and a lighting assembly mounted within the sealing cover, and a transmission box mounted on the sidewall of the bridge pier. The bottom end of the transmission box is rotatably connected to a water wheel via a water wheel shaft. The transmission box is used to convert the rotation of the water wheel caused by the water flow into the lifting and lowering movement of the sealing cover. The amount of foundation scour is analyzed by comparing the original image with the image after scouring and combining the number of rotations. The method determines the amount of scour based on the water flow velocity, but there is currently no authoritative reference standard to measure the feasibility of this method. Furthermore, the scour amount obtained is not accurate. Assuming that the scour amount 1 is obtained by the number of rotations of the water wheel driven by the water flow in the forward direction and the scour amount 2 is obtained by the number of rotations of the water wheel driven by the water flow in the reverse direction is not necessarily a simple summation.

[0010] Patent CN 113373994 A - A Bridge Foundation Scour Monitoring Assembly. This invention discloses a bridge foundation scour monitoring assembly comprising: an acquisition module, a transmission module, and an analysis module; both the acquisition module and the analysis module are connected to the transmission module. The acquisition module is configured to: transmit ultrasonic waves toward the riverbed; receive ultrasonic echoes reflected from the riverbed; convert the ultrasonic echoes into voltage signals and transmit the voltage signals to the transmission module; the transmission module is configured to transmit the voltage signals to the analysis module; and the analysis module is configured to calculate the scour depth of the riverbed based on the voltage signals. The present invention utilizes ultrasonic waves to detect the scour depth of the riverbed. The propagation of ultrasonic waves is unaffected by external factors, and the accuracy of scour depth measurement is higher. However, scour monitoring of offshore wind turbine foundation structures differs significantly from scour monitoring of bridges or riverbeds. Scour in inland rivers is relatively gentle, while the marine environment is more severe and scour conditions at sea are much more severe. The reliability of the device remains to be verified. Secondly, if the scour monitoring device is directly installed on the seabed near the offshore wind turbine, there will be a monitoring blind spot, and the overall three-dimensional morphology of the scour pit cannot be imaged. Finally, due to the remote location of offshore wind turbines and the unpredictable offshore environment, changes in scour conditions may occur in a short period of time or may not occur for a long time after installation. This requires that the scour monitoring device for the offshore wind turbine foundation structure be maintenance-free.

[0011] Therefore, in order to solve the above problems, an offshore wind turbine foundation scour depth monitoring device and installation method are proposed. Summary of the Invention

[0012] The purpose of the present invention is to overcome the existing defects and provide an offshore wind turbine foundation scour depth monitoring device and installation method, which has the characteristics of simplicity and convenience, accurate monitoring, real-time dynamic monitoring of the entire process and recyclability. The corresponding installation method improves the efficiency of scour depth and scour pit three-dimensional morphology monitoring.

[0013] The technical solution to achieve the above-mentioned purpose is: a device for monitoring the scour depth of an offshore wind turbine foundation, comprising an operation and maintenance platform and a monitoring component; the operation and maintenance platform and the monitoring component are both connected to the side wall of the wind turbine foundation, the operation and maintenance platform is located above the monitoring component, the lower end of the wind turbine foundation is inserted below the mud line, the monitoring component is located below the sea level, and the operation and maintenance platform is located above the sea level; the operation and maintenance platform is connected to the monitoring component via a suspension rope.

[0014] Preferably, the operation and maintenance platform is an annular hollow mesh bracket, and the annular hollow mesh bracket is fixedly connected to the side wall of the wind turbine foundation.

[0015] Preferably, the monitoring assembly includes an inflatable bag, an inner ring, an outer ring, multiple supports and a monitor; the inflatable bag is connected to the inner wall of the inner ring, multiple supports are equidistantly connected to the outer wall of the inner ring, the outer ends of multiple supports are connected to the inner wall of the outer ring, and the lower end of the outer ring is slidably connected to the monitor; the inflatable bag is connected to the outer wall of the fan foundation.

[0016] Preferably, each of the upper end surfaces of the supports is connected to a first water pressure sensor and a pull ring, the lower end of the suspension rope is connected to the pull ring, and the upper end is connected to the operation and maintenance platform.

[0017] Preferably, the monitor includes two depth sounding probes, which are respectively connected to the two ends of the rotating shaft, the rotating shaft is rotatably connected to the lower end of the vertical rod, the upper end of the vertical rod is connected to the groove slider, the lower end of the outer ring is provided with a groove slide, and the groove slider is slidably connected in the groove slide.

[0018] Preferably, a driving device is provided inside the outer ring for driving the groove slider to move along the circumference of the groove slideway.

[0019] Preferably, a second water pressure sensor is provided at the mud line, and the second water pressure sensor is connected to the first water pressure sensor through an electrical signal.

[0020] A method for installing an offshore wind turbine foundation scour depth monitoring device comprises the following steps:

[0021] Step 1: Preparation before wind turbine foundation construction: Before installing the wind turbine foundation, take advantage of the fact that the inner diameter of the monitoring component is larger than the outer diameter of the wind turbine foundation. The monitoring component is placed on the wind turbine foundation and adjusted to the appropriate position. The inflatable bag is inflated to fix the monitoring component to the outer wall of the wind turbine foundation. The position of the monitoring component remains unchanged during this stage. The wind turbine foundation is then hoisted into the guide hole of the positioning platform and the monitoring component is fixed to the operation and maintenance platform using a lifting rope.

[0022] Step 2: Monitoring the scour depth during the wind turbine foundation construction process: During the installation of the wind turbine foundation, the inflatable bag is deflated to reduce its volume, resulting in a loose or no connection between it and the wind turbine foundation, preventing the monitoring component and the wind turbine foundation from sinking below the mudline together. At the same time, the suspension rope is loosened on the operation and maintenance platform to gradually lower the depth of the monitoring component. The operation is stopped when the depth reaches the limit, at which point the wind turbine foundation installation is complete. During this stage, scour occurs in the area around the wind turbine foundation, and the scour depth gradually increases with the installation depth, that is, the installation time, ranging from zero to one times the pile diameter.

[0023] When the wind turbine foundation is not installed in place: at this stage, the monitoring component is gradually lowered by loosening the suspension rope, that is, the distance from the monitoring component to the mud line gradually changes with the installation process of the wind turbine foundation; in order to facilitate the explanation of the monitoring principle, the scouring depth at a certain moment is taken as an example; at this moment, the measurement value of the first water pressure sensor on the support of the monitoring component and the measurement value of the second water pressure sensor at the mud line are known, and the distance L between the first water pressure sensor and the second water pressure sensor can be obtained by calculating the difference between the two. Here, for error considerations, the measurement value of the first water pressure sensor on the support is determined when the monitoring component is horizontal. If the measurement values ​​of the first water pressure sensors on the four supports are different, it means that the monitoring component is tilted, and the monitoring component is kept horizontal by adjusting the length of the suspension rope; since the distance between the first water pressure sensor on the support and the depth probe is fixed at L0, the measurement The distance from the deep probe to the mud line can be calculated as L1=L-L0 through the distance difference; the sounding probe monitors the scour depth of the measured point by rotating a certain angle α1. The rotation angle α1 is known, and the distance from the sounding probe to the measured point is s1. The sounding probe has been measured, then the scour depth of the measured point is Δh1=s1cosα1-L1, where if the rotation angle α1 is less than 90°, the rotation angle α1 is used when calculating the scour depth; if the rotation angle α1 is greater than 90°, the rotation angle α1-90° is used when calculating the scour depth; due to the change relationship between the scour depth and time, the scour depth of each point on a certain section measured by the sounding probe through the rotation angle cannot reflect the scour depth of each point on the section at a certain moment measured in the actual process. Therefore, in order to make the measurement result more accurate, a sounding probe with a fixed position is set up to vertically monitor the change relationship between the scour depth of the point below it and time, and the relationship function S between the scour depth and time is obtained. L =S L (t); Assuming that the time for the sounding probe to rotate from the previous monitoring point to the next monitoring point is t, the relationship function S between the measured scour depth and time is L =S L (t), find the scour depth S1 corresponding to the time of the previous monitoring point and the scour depth S2 corresponding to the time of the next monitoring point, then β1=S2 / S1 is the rate of change of the scour depth with time, and the accurate scour depth can be calculated through the rate of change of the scour depth with time, that is, Δh′1=(s1 cosα1-L1) / β1; after the scour depths of all points at the cross section are fully monitored, the groove slide at the bottom of the outer ring drives the monitor connected to it to realize circumferential movement, and the scour depth of each point within the circumferential range of the wind turbine foundation is monitored. After that, the scour depth monitoring data is transmitted to the data receiving platform, and the scour pit morphology is imaged in three dimensions using three-dimensional imaging software;

[0024] When the installation of the wind turbine foundation is completed: at this stage, the lifting rope is completely relaxed, and the depth of the monitoring component drops to the limit, that is, the distance from the monitoring component to the mud line is fixed, and the air bag is inflated to expand the volume of the air bag. At this time, the air bag is in close contact with the outer wall of the wind turbine foundation, that is, the monitoring component is fixed on the outer wall of the wind turbine foundation; in order to facilitate the explanation of the monitoring principle, the scouring depth at a certain moment is used as an example; at this moment, the measurement value of the first water pressure sensor on the support of the monitoring component and the measurement value of the first water pressure sensor at the mud line are known, and the distance L' between the first water pressure sensor and the second water pressure sensor can be obtained by calculating the difference between the two. Here, due to the error Consider that the measurement value of the first water pressure sensor on the support is determined when the monitoring component is horizontal. If the measurement values ​​of the first water pressure sensors on the four supports are different, it means that the monitoring component is tilted. The monitoring component is kept horizontal by adjusting the length of the suspension rope. Since the distance between the first water pressure sensor on the support and the depth probe is fixed at L0, the distance from the depth probe to the mud line can be calculated as L2=L′-L0 through the distance difference. The depth probe monitors the scouring depth of the measured point by rotating a certain angle α2. The rotation angle α2 is known, and the distance from the depth probe to the measured point is s2. The depth probe has measured it, so the scouring depth of the measured point Δh2=s2 cosα2-L2, where if the rotation angle α2 is less than 90°, the rotation angle α2 is used when calculating the scour depth; if the rotation angle α2 is greater than 90°, the rotation angle α2-90° is used when calculating the scour depth; due to the relationship between the scour depth and time, the scour depth of each point on a certain section measured by the depth probe through the rotation angle cannot reflect the scour depth of each point on the section at a certain moment in the actual process. Therefore, in order to make the measurement result more accurate, a depth probe with a fixed position is set up to vertically monitor the relationship between the scour depth of the point below it and time, and the relationship function S between the scour depth and time is obtained. L =S L (t); Assuming that the time for the sounding probe to rotate from the previous monitoring point to the next monitoring point is t, the relationship function S between the measured scour depth and time is L =S L(t), find the scour depth S3 corresponding to the time of the previous monitoring point and the scour depth S4 corresponding to the time of the next monitoring point, then β2=S4 / S3 is the rate of change of the scour depth with time, and the accurate scour depth can be calculated through the rate of change of the scour depth with time, that is, Δh′2=(s2 cosα2-L2) / β2; after the scour depths of all points at the cross section are monitored, the groove slide at the bottom of the outer ring drives the monitor connected to it to realize circumferential movement, and the scour depth of each point within the circumferential range of the wind turbine foundation is monitored. After that, the scour depth monitoring data is transmitted to the data receiving platform, and the scour pit morphology is imaged in three dimensions using three-dimensional imaging software;

[0025] Step 3: Dynamic scour depth monitoring during the service phase of the wind turbine foundation: The wind turbine foundation begins its service process after installation. As the service time of the wind turbine foundation increases, the scour around the foundation continues. The scour radius of the soil around the foundation and the shape of the scour pit also change. The scour depth changes from one pile diameter to two pile diameters.

[0026] At this stage, the suspension rope is completely relaxed, and the monitoring component's descent depth reaches the limit, that is, the distance from the monitoring component to the mudline is fixed. In order to explain the monitoring principle, the scouring depth at a certain moment is used as an example. At this moment, the measurement value of the first water pressure sensor on the support of the monitoring component and the measurement value of the second water pressure sensor at the mudline are known. The distance L' between the first water pressure sensor and the second water pressure sensor can be obtained by calculating the difference between the two. Here, due to error considerations, the measurement value of the first water pressure sensor on the support is determined when the monitoring component is horizontal. If the measured values ​​of the first water pressure sensors on the four supports are different, it means that the monitoring assembly is tilted. The monitoring assembly can be kept in a horizontal state by adjusting the length of the suspension rope. Since the distance between the first water pressure sensor on the support and the depth probe is fixed at L0, the distance from the depth probe to the mud line can be calculated by the distance difference as L2=L′-L0. The depth probe monitors the scouring depth of the measured point by rotating a certain angle α3. The rotation angle α3 is known, and the distance from the depth probe to the measured point is s3. The depth probe has measured the scouring depth of the measured point Δh3=s3. cosα3-L2, where if the rotation angle α3 is less than 90°, the rotation angle α3 is used when calculating the scour depth; if the rotation angle α3 is greater than 90°, the rotation angle α3-90° is used when calculating the scour depth; due to the relationship between the scour depth and time, the scour depth of each point on a certain section measured by the depth probe through the rotation angle cannot reflect the scour depth of each point on the section at a certain moment in the actual process. Therefore, in order to make the measurement result more accurate, a depth probe with a fixed position is set up to vertically monitor the relationship between the scour depth of the point below it and time, and the relationship function S between the scour depth and time is obtained.L =S L (t); Assuming that the time for the sounding probe to rotate from the previous monitoring point to the next monitoring point is t, the relationship function S between the measured scour depth and time is L =S L (t), find the scour depth S5 corresponding to the time of the previous monitoring point and the scour depth S6 corresponding to the time of the next monitoring point, then β3=S6 / S5 is the rate of change of the scour depth with time, and the accurate scour depth can be calculated through the rate of change of the scour depth with time, that is, Δh′3=(s3 cosα3-L2) / β3; after the scour depths of all points at the cross section are fully monitored, the groove slide at the bottom of the outer ring drives the monitor connected to it to realize circumferential movement, and the scour depth of each point within the circumferential range of the wind turbine foundation is monitored. After that, the scour depth monitoring data is transmitted to the data receiving platform, and the scour pit morphology is imaged in three dimensions using three-dimensional imaging software;

[0027] Step 4: Monitoring the stable scour depth during the service phase of the wind turbine foundation: At this stage, the scour depth reaches a balanced state, and the scour depth is twice the pile diameter. Ignoring the change of the scour depth with time, the scour pit shape tends to be stable. It is only necessary to measure the scour depth of each point at any cross section and obtain the stabilized scour pit shape. In order to facilitate the explanation of the monitoring principle, the scour depth at a certain moment is used as an example. At this moment, the measurement value of the first water pressure sensor on the support of the monitoring component and the measurement value of the second water pressure sensor at the mud line are known. The distance L' between the first water pressure sensor and the second water pressure sensor can be obtained by calculating the difference between the two. Here, for error considerations, The measurement value of the water pressure sensor on the support is determined when the monitoring component is horizontal. If the measurement values ​​of the first water pressure sensors on the four supports are different, it means that the monitoring component is tilted. The monitoring component is kept horizontal by adjusting the length of the suspension rope. Since the distance between the first water pressure sensor on the support and the depth probe is fixed at L0, the distance from the depth probe to the mud line can be calculated as L2=L′-L0 through the distance difference. The depth probe monitors the scouring depth of the measured point by rotating a certain angle α4. The rotation angle α4 is known, and the distance from the depth probe to the measured point is s4. The depth probe has measured the scouring depth of the measured point Δh4=s4. cosα4-L2, where if the rotation angle α4 is less than 90°, the rotation angle α4 is used when calculating the scour depth; if the rotation angle α4 is greater than 90°, the rotation angle α4-90° is used when calculating the scour depth; after the scour depths of all points at the cross section are monitored, the groove slideway at the bottom of the outer ring drives the monitor connected to it to achieve circumferential movement, and the scour depth of each point within the circumference of the wind turbine foundation is monitored. The scour depth monitoring data is then transmitted to the data receiving platform, and three-dimensional imaging software is used to perform three-dimensional imaging of the scour pit morphology;

[0028] Step 5: Determine the scour range around the wind turbine foundation: As the scour depth changes, the scope of the scour pit also gradually changes. How to determine the boundary of the scour pit is an extremely important step;

[0029] When the rotation angle of the depth sounding probe is less than 90°, the problem to be solved in the area between the depth sounding probe and the fan foundation is how to determine the intersection point of the fan foundation and any cross section of the scour pit, that is, the maximum scour depth point of the fan foundation; in the process of changing the rotation angle of the depth sounding probe from small to large, the measured distance is first the distance from the depth sounding probe to each point in the axial direction of the fan foundation, and this measured distance gradually increases with the increase of the rotation angle; secondly, the measured distance is the distance from the depth sounding probe to the point belonging to the scour pit in the area, and this measured distance gradually decreases with the increase of the rotation angle; therefore, at a certain cross section, when the rotation angle of the depth sounding probe is less than 90°, the point with the largest measured distance is the maximum scour depth point;

[0030] When the rotation angle of the depth probe is greater than 90°, the problem to be solved in the area between the scour pit section and the mud line is how to determine the intersection of the mud line and any section of the scour pit, that is, the maximum scour depth radius of the wind turbine foundation; when the rotation angle of the depth probe changes from small to large, the distance to each point of the scour pit section in the area gradually increases with the increase of the rotation angle. To determine the maximum scour depth radius, it is necessary to analyze it in combination with the geometric relationship; since the vertical distance from the depth probe to the mud line is known and set as Z1, the distance between the depth probe and the point to be measured is known and set as Z2, and the rotation angle of the depth probe is known and set as β, if The vertical distance from the monitoring point to the wind turbine foundation is considered to be the maximum impact radius of the wind turbine foundation;

[0031] Measurement of the accumulation height on the dorsum side of the fan foundation when the depth probe moves circumferentially: During the scouring process of the fan foundation, soil accumulation will occur on the dorsum side. The problem to be solved is how to measure the height of the accumulated soil and determine the maximum boundary of the scouring pit; the shape of the soil accumulation can be seen as an axisymmetric structure according to literature search. When the depth probe moves to the accumulation area to measure the scouring depth, its distance to each point within the accumulation range is uncertain. To determine the height of the accumulated soil and the maximum boundary of the scouring pit, it is necessary to analyze it in combination with geometric relationships; combined with the determination of the maximum scouring depth radius of the fan foundation scouring, the vertical distance from this point to the depth probe is known and set as Z3, and the vertical distance from this point to the fan foundation is known and set as Z4. Continuing to increase the rotation angle of the depth probe, the measurement of the accumulated soil height begins; since the rotation angle of the depth probe is known and set as γ, the distance from the depth probe to each point within the accumulation range is known and set as Z5, then the vertical distance between each point within the accumulation range and the depth probe can be calculated and set as Z6=Z5 cosγ, where the monitoring point corresponding to the minimum vertical distance Z6 between the measured point and the sounding probe is the highest point of the accumulated soil, and the accumulation height at this time is Z3-Z6; the horizontal distance from the maximum accumulation height point to the maximum scour radius point is Z7=Z5 sinγ through geometric relationships, and the maximum boundary of the scour pit is Z4+2Z5 sinγ;

[0032] Step 6: Repair and recycling of the scour depth monitoring device: When the wind turbine foundation is decommissioned or the monitoring component fails, the monitoring component is lifted to sea level by lifting the rope tied under the operation and maintenance platform, so that the entire monitoring device can be repaired and reused.

[0033] The beneficial effects of the present invention are:

[0034] 1) This offshore wind turbine foundation scour depth monitoring device and installation method can maintain its own relative position change as the installation depth of the wind turbine foundation increases during the installation process by setting up a monitoring component. The scour depth of a certain monitoring point around the wind turbine foundation during the installation process is measured by combining the difference of the water pressure sensor with the monitoring angle of the depth sounding probe. At the same time, the relationship between the scour depth of the wind turbine foundation and time is taken into account to obtain a relationship function of the scour depth changing with time, and this function is used to correct the monitored scour depth. In addition, by analyzing the characteristic points of the scour boundary, the method for determining the characteristic points is obtained using geometric relationships, thereby realizing scour depth monitoring of each point in the entire cross-section. At the same time, the depth sounding probe can also make circumferential motion on the slide through the slider to realize scour depth monitoring of the 360° area around the wind turbine foundation. Finally, the monitoring data is transmitted to the data receiving platform, and the three-dimensional scour pit morphology is imaged by the computer, thereby realizing scour depth detection and three-dimensional scour pit morphology imaging throughout the installation and service process.

[0035] 2) The monitoring component determines the height from the monitoring component to the mudline by analyzing the difference between the two water pressure sensors installed at the monitoring component and the mudline. Combined with the installation position of the depth probe, the height from the depth probe to the mudline is determined. By comparing the values ​​of the four sets of water pressure sensors, it is determined whether the monitoring component is in a horizontal state, and the position of the component is monitored in time by pulling the rope to reduce the error in the height calculation from the depth probe to the mudline. According to the rotation angle of the depth probe and the distance from the depth probe to the monitoring point, combined with the known height from the depth probe to the mudline, the scour depth at the monitoring point is solved using geometric relationships. The influence of the rotation time of the depth probe on the scour depth measurement result is considered, and the relationship function of the scour depth changing with time is used to correct the measurement result. In this process, since the rotation angle of the depth probe can be accurately measured, the distance error from the depth probe to the monitoring point is controlled by the error accuracy of the depth probe itself, and the error of the measured height from the depth probe to the mudline is small, therefore, the error of the entire monitoring process is small. Then, the circumferential movement of the sounding probe is achieved through the annular slide, and the monitoring process is repeated to complete the monitoring of the scour depth at any point in the area around the foundation and use a computer to draw the three-dimensional scour pit shape of the wind turbine foundation based on the monitored scour depth data. This process is the result of repeating the above monitoring process. Since the error of the above monitoring process is low, the overall error can also be controlled within a lower range, thereby obtaining more accurate monitoring data.

[0036] 3) Because traditional monitoring devices are difficult to repair when they malfunction, this monitoring unit can be raised and lowered using a rope installed beneath the operation and maintenance platform. Since the platform is fixed and always above sea level, if a monitoring unit malfunctions, maintenance personnel can simply retract the rope using a simple lifting mechanism, raising the monitoring unit to sea level for easy troubleshooting. Once repairs are complete, the rope can be released using the simple lifting mechanism, allowing the monitoring unit to descend to its intended monitoring position.

[0037] 4) Given the high monitoring costs of traditional monitoring devices, this monitoring component not only shortens maintenance time in the event of a fault, saving a significant amount of maintenance costs, but also allows the monitoring component to be lifted to sea level after the wind turbine foundation is decommissioned using a simple lifting device arranged on the operation and maintenance platform, enabling the entire monitoring device to be recovered and reused, greatly reducing monitoring costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a front view of the offshore wind turbine foundation scour depth monitoring device of the present invention;

[0039] Figure 2 2. It is a top view of the offshore wind turbine foundation scour depth monitoring device of the present invention;

[0040] Figure 3 is a top view of the monitoring assembly of the present invention;

[0041] Figure 4 is a front view of the monitoring assembly of the present invention;

[0042] Figure 5 is a detailed diagram of the monitor of the present invention;

[0043] Figure 6 is a front view of the scour depth monitoring during the installation process of step 1 of the installation method of the present invention;

[0044] Figure 7 is a front view of detailed scour depth monitoring during the installation process of step 1 of the installation method of the present invention;

[0045] Figure 8 This is a front view of the scour depth monitoring after the installation of step 2 of the installation method of the present invention is completed;

[0046] Figure 9 This is a front view of the detailed scour depth monitoring after the installation of step 2 of the installation method of the present invention is completed;

[0047] Figure 10 This is a front view of the scouring depth monitoring during the dynamic scouring phase of step three of the installation method of the present invention;

[0048] Figure 11This is a front view of the detailed scouring depth monitoring during the dynamic scouring phase of step three of the installation method of the present invention;

[0049] Figure 12 This is a front view of the scouring depth monitoring during the stable scouring phase in step 4 of the installation method of the present invention;

[0050] Figure 13 It is a front view of the process of determining the flushing boundary in step five of the installation method of the present invention.

[0051] In the figure: 1. Wind turbine foundation; 2. Operation and maintenance platform; 21. Annular hollow mesh bracket; 3. Monitoring component; 3-1. Inflatable bag; 3-2. Inner ring; 3-3. Outer ring; 3-31. Grooved slide; 3-4. Support; 3-41. First water pressure sensor; 3-42. Pull ring; 3-5. Monitor; 3-51. Grooved slider; 3-52. Vertical rod; 3-53. Rotating shaft; 3-54. Depth probe; 4. Sea level; 5. Mud line; 6. Lifting rope. DETAILED DESCRIPTION

[0052] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0053] The present invention will be further described below with reference to the accompanying drawings.

[0054] The presence of foundations in the marine environment alters the initial flow structure in the area surrounding the foundations. The obstruction of the foundations causes streamlines to contract, slightly raising the upper water surface in front of the foundations and diverting the lower water flow downward. This results in a horseshoe-shaped vortex in front of the foundations and a wake vortex behind them. The vortex and turbulence increase the flow velocity near the foundations, causing the upper pressure at the seabed mud surface to decrease while the lower pressure remains constant. This creates a pressure differential between the upper and lower sides of the seabed soil, inducing soil liquefaction. Consequently, the seabed soil is lost under the influence of the currents, causing scour. [Hazards of Foundation Scour] Under the influence of vortices and turbulence, scour occurs around foundations, forming scour pits. The damage caused by scour increases over time. Scour reduces the foundation's buried depth, significantly weakening its bearing capacity. This also increases the eccentricity of the bearing load, seriously threatening the safe operation of offshore wind farms. [Existing Methods for Monitoring Foundation Scour Depth]: Existing methods for monitoring foundation scour depth include contact monitoring and non-contact monitoring. Contact monitoring involves installing components around the foundation, on which soil pressure sensors, water pressure sensors, or electrode probes are installed. Non-contact monitoring involves using external terrain exploration equipment (ultrasonic, sonar, light sensors, etc.) to regularly monitor the scour conditions around the foundation. [Problems with existing foundation scour depth monitoring]: First, although contact monitoring can achieve periodic scour depth monitoring, since it is achieved through components installed around the foundation, the installation resistance of the foundation increases, making the installation process difficult. Second, since it is fixed around the bottom of the foundation, it is very difficult to repair when the monitoring component fails. Third, since it indirectly derives the scour depth by monitoring changes in soil pressure and water pressure, and does not derive the scour depth by differentiating multiple sensors, it is easily affected by the complex marine environment, resulting in inaccurate measured data. Finally, it uses limited sensors to monitor the scour depth of local feature points and cannot monitor the morphology of three-dimensional scour pits. Although non-contact monitoring can accurately monitor the scour depth and three-dimensional scour pit morphology, it cannot monitor the entire service life of the foundation and transmit data in a timely manner. Moreover, its monitoring process mainly relies on renting a topographic survey ship and using the monitoring equipment on the ship to image the scour depth and scour pit morphology. Not only can it not achieve real-time dynamic monitoring, but the monitoring cost is also expensive.

[0055] like Figure 1-5 As shown, an offshore wind turbine foundation scour depth monitoring device includes an operation and maintenance platform 2 and a monitoring assembly 3. Both the operation and maintenance platform 2 and the monitoring assembly 3 are connected to the side wall of the wind turbine foundation 1. The operation and maintenance platform 2 is located above the monitoring assembly 3. The lower end of the wind turbine foundation 1 is inserted below the mudline 5. The monitoring assembly 3 is located below sea level 4, and the operation and maintenance platform 2 is located above sea level 4. The operation and maintenance platform 2 is connected to the monitoring assembly 3 via a suspension rope 6. The operation and maintenance platform 2 is an annular hollow mesh support 21, which is fixedly connected to the side wall of the wind turbine foundation 1.

[0056] Specifically, the operation and maintenance platform 2 is typically a square steel structure. Its primary function is to anchor the monitoring assembly 3 and provide a workstation for maintenance personnel during troubleshooting. At least four anchor points are reserved at the bottom of the operation and maintenance platform 2 for the passage of the suspension rope 6. During the installation of the wind turbine foundation 1, personnel on the operation and maintenance platform 2 can loosen the suspension rope to increase its submersion depth, enabling dynamic scour depth monitoring during installation. The height of the operation and maintenance platform 2 is higher than sea level 4, thereby reducing seawater corrosion on the operation and maintenance platform 2 and facilitating maintenance.

[0057] Specifically, the monitoring assembly 3 includes an inflatable bag 3-1, an inner ring 3-2, an outer ring 3-3, multiple supports 3-4, and a monitor 3-5. The inflatable bag 3-1 is connected to the inner wall of the inner ring 3-2, and multiple supports 3-4 are equidistantly connected to the outer wall of the inner ring 3-2. The outer ends of the multiple supports 3-4 are connected to the inner wall of the outer ring 3-3, and the lower end of the outer ring 3-3 is slidably connected to the monitor 3-5. The inflatable bag 3-1 is connected to the outer wall of the wind turbine foundation 1. The upper end of each support 3-4 is connected to a first water pressure sensor 3-41 and a pull ring 3-42. The lower end of the suspension rope 6 is connected to the pull ring 3-42, and the upper end is connected to the operation and maintenance platform 2. The monitor 3-5 includes two sounding probes 3-54, which are connected to the ends of a rotating shaft 3-53. The rotating shaft 3-53 is rotatably connected to the lower end of a vertical rod 3-52. The upper end of the vertical rod 3-52 is connected to a groove slider 3-51. The lower end of the outer ring 3-3 is provided with a groove slide 3-31, and the groove slider 3-51 is slidably connected within the groove slide 3-31. A driving device is provided inside the outer ring 3-3 for driving the groove slider 3-51 to move in a circular motion along the groove slide 3-31.

[0058] Specifically, a second water pressure sensor is provided at the mud line 5, and the second water pressure sensor is connected to the first water pressure sensor 3-41 through an electrical signal.

[0059] Specifically, the monitoring component 3 is a double-circular hollow structure, and its main function is to monitor the scouring depth of the wind turbine foundation 1 during the entire installation and service process and transmit the monitoring data back to the data receiving platform. At the same time, the data is processed using three-dimensional imaging software to generate the three-dimensional shape of the scouring pit throughout the installation and service cycle.

[0060] Specifically, the inflatable bladder 3-1 is a flexible, hollow ring-shaped material that changes volume through inflation and deflation. The surface of the bladder 3-1 has a certain degree of roughness, providing significant friction. The bladder 3-1 is attached to the inner side of the inner ring 3-2, creating a fixed connection. By inflating the bladder 3-1 and expanding its volume, the monitoring assembly 3 is firmly attached to the sidewall of the wind turbine foundation 1, securing the monitoring assembly 3.

[0061] Specifically, the inner ring 3-2 is a circular ring with a certain thickness and height, an inner area of ​​which is fixedly connected to the inflatable bag 3-1, and an outer area is connected to the outer ring 3-3 through the support 3-4.

[0062] Specifically, the outer ring 3-3 is a circular ring of a certain thickness and height. Its inner side is connected to the inner ring 3-2 via a support 3-4. The bottom end is provided with an extended slide 3-31. The extended slide 3-31 is connected to the monitor 3-5. The internal transmission system of the extended slide 3-31 can make the monitor 3-5 installed on the groove slide 3-31 move in a circular direction.

[0063] Specifically, support 3-4 is a rectangular steel member of a certain thickness and width. It serves as a connecting component, with a first water pressure sensor 3-41 and a pull ring 3-42 mounted on its upper portion. Its ends connect to the outer side of inner ring 3-2 and the inner side of outer ring 3-3, respectively. Support 3-4, inner ring 3-2, and outer ring 3-3 are secured together by welding. At least four supports 3-4 are provided, evenly spaced circumferentially at predetermined angles.

[0064] Specifically, the first water pressure sensor 3-41 can measure the water pressure at the height of the monitoring assembly 3. By calculating the difference between the first water pressure sensor 3-41 and the second water pressure sensor installed at the mudline 5, the distance between the monitoring assembly 3 and the mudline 5 can be determined. Then, by subtracting the fixed distance between the first water pressure sensor 3-41 on the support 3-4 and the depth probe 3-54, the distance between the depth probe 3-54 and the mudline 5 can be obtained. At the same time, by comparing the water pressure values ​​measured by the first water pressure sensors 3-41 on different supports 3-4, it can be determined whether the monitoring assembly 3 is horizontal and its tilt angle. There are at least four pull rings 3-42, with a lifting rope 6 passing through the middle. The lifting rope 6 is connected to the operation and maintenance platform 2. The operation and maintenance personnel can drive the monitoring assembly 3 up and down by lifting and loosening the lifting rope, thereby realizing dynamic monitoring of the scouring depth and fault repair.

[0065] Specifically, the monitor 3-5 is connected to the groove slide 3-31 at the lower end of the outer ring 3-3 via a groove slider 3-51. The groove slide 3-31 is internally driven, causing the connected groove slider 3-51 to move circumferentially, thereby enabling circumferential scouring depth monitoring of the wind turbine foundation 1. The groove slider 3-51 is a block with an inverted T-shaped slot on the top. One end is connected to the groove slide 3-31, and the other end is connected to the depth probe 3-54 via a vertical rod 3-52 and a rotating shaft 3-53 at the end of the vertical rod 3-52. The vertical rod 3-52 mainly serves as a connection. Its upper end is connected to the groove slider 3-51, and its lower end is a rotating shaft 3-53, which is connected to the depth probe 3-54 via the rotating shaft 3-53. At least two sounding probes 3-54 are provided. One is fixed at a fixed angle and position, vertically downwardly monitoring the relationship between scour depth and time, and the other is adjustable in angle and circumferentially moving to monitor the scour depth at any point within a 360° range. The sounding probe 3-54 can only emit a single ray at a time to measure the distance from the measured point to the sounding probe 3-54. The hinge at the lower end of the connecting rod 3-52 allows the probe to rotate within a 180-degree angle within the plane in which it is located, thereby monitoring the scour depth at any point within the plane in which it is located.

[0066] Specifically, at least a second water pressure sensor is provided at the far end of the mud line 5. By measuring the water pressure at the mud line 5, the difference between it and the first water pressure sensor on the support 3-4 is determined. By using the geometric relationship and combining the rotation angle of the depth probe 3-54, the scouring depth at any point in the scouring range is obtained.

[0067] like Figure 6-13 As shown, a method for installing an offshore wind turbine foundation scour depth monitoring device includes the following steps:

[0068] Step 1: Preparation before construction of wind turbine foundation 1: Before installing wind turbine foundation 1, take advantage of the fact that the inner diameter of monitoring assembly 3 is larger than the outer diameter of wind turbine foundation 1, put monitoring assembly 3 on wind turbine foundation 1, and adjust monitoring assembly 3 to the appropriate position. Inflate the inflatable bag 3-1 to fix monitoring assembly 3 on the outer wall of wind turbine foundation 1. The position of monitoring assembly 3 remains unchanged at this stage. Then, hoist wind turbine foundation 1 to the guide hole of positioning platform and fix monitoring assembly 3 to operation and maintenance platform 2 with the hoisting rope.

[0069] Step 2: Monitoring the scouring depth during the construction of the wind turbine foundation 1: During the installation of the wind turbine foundation 1, the air bag 3-1 is deflated to reduce its volume, making it loosely connected or disconnected from the wind turbine foundation 1, preventing the monitoring component 3 and the wind turbine foundation 1 from sinking below the mud line 5 together. At the same time, the suspension rope 6 is loosened on the operation and maintenance platform 2 to gradually lower the depth of the monitoring component 3. The operation is stopped when the depth reaches the limit, and the installation of the wind turbine foundation 1 is now complete. During this stage, scouring occurs in the area around the wind turbine foundation 1, and the scouring depth gradually increases with the installation depth, i.e., the installation time, and the scouring depth varies from zero to one pile diameter.

[0070] When the wind turbine foundation 1 is not installed in place: at this stage, the monitoring component 3 is gradually lowered by loosening the suspension rope 6, that is, the distance from the monitoring component 3 to the mud line 5 gradually changes with the installation process of the wind turbine foundation 1; in order to facilitate the explanation of the monitoring principle, the scouring depth at a certain moment is used as an example to illustrate; at this moment, the measurement value of the first water pressure sensor 3-41 on the support 3-4 in the monitoring component 3 and the measurement value of the second water pressure sensor at the mud line 5 are known, and the distance L between the first water pressure sensor 3-41 and the second water pressure sensor can be calculated by calculating the difference between the two. Here, for error considerations, the measurement value of the first water pressure sensor 3-41 on the support 3-4 is determined when the monitoring component 3 is horizontal. It is concluded that if the measured values ​​of the first water pressure sensors 3-41 on the four supports 3-4 are different, it means that the monitoring component 3 is tilted, and the monitoring component 3 is kept in a horizontal state by adjusting the length of the suspension rope 6; since the distance between the first water pressure sensor 3-41 on the support 3-4 and the depth probe 3-54 is fixed at L0, the distance from the depth probe 3-54 to the mud line 5 can be calculated as L1=L-L0 by the distance difference; the depth probe 3-54 monitors the scouring depth of the measured point by rotating a certain angle α1, and its rotation angle α1 is known, and the distance from the depth probe 3-54 to the measured point is s1. The depth probe 3-54 has been measured, so the scouring depth of the measured point Δh1=s1 cosα1-L1, where if the rotation angle α1 is less than 90°, the rotation angle α1 is used when calculating the scour depth; if the rotation angle α1 is greater than 90°, the rotation angle α1-90° is used when calculating the scour depth; due to the relationship between the scour depth and time, the scour depth of each point on a certain section measured by the depth probe 3-54 through the rotation angle cannot reflect the scour depth of each point on the section at a certain moment in the actual process. Therefore, in order to make the measurement result more accurate, another depth probe 3-54 with a fixed position is set up to vertically monitor the relationship between the scour depth of the point below it and time, and the relationship function S between the scour depth and time is obtained. L =S L(t); Assuming that the time for the sounding probe 3-54 to rotate from the previous monitoring point to the next monitoring point is t, the relationship function S between the measured scour depth and time is L =S L (t), find the scour depth S1 corresponding to the time of the previous monitoring point and the scour depth S2 corresponding to the time of the next monitoring point, then β1=S2 / S1 is the rate of change of the scour depth with time, and the accurate scour depth can be calculated through the rate of change of the scour depth with time, that is, Δh′1=(s1 cosα1-L1) / β1; after the scour depths of all points at the cross section are monitored, the groove slide 3-31 at the lower part of the outer ring 3-3 drives the monitor 3-5 connected thereto to realize circumferential movement, and monitors the scour depths of all points within the circumferential range of the wind turbine foundation 1, and then transmits the scour depth monitoring data to the data receiving platform, and uses three-dimensional imaging software to perform three-dimensional imaging of the scour pit morphology;

[0071] When the wind turbine foundation is installed: at this stage, the lifting rope 6 is completely relaxed, and the depth of the monitoring component 3 descending reaches the limit, that is, the distance from the monitoring component 3 to the mud line 5 is fixed, and the air bag 3-1 is inflated to expand the volume of the air bag 3-1. At this time, the air bag 3-1 is in close contact with the outer wall of the wind turbine foundation 1, that is, the monitoring component 3 is fixed on the outer wall of the wind turbine foundation 1; in order to facilitate the explanation of the monitoring principle, the scouring depth at a certain moment is used as an example; at this moment, the measurement value of the first water pressure sensor 3-41 on the support 3-4 in the monitoring component 3 and the measurement value of the first water pressure sensor 3-41 at the mud line 5 are known, and the distance L between the first water pressure sensor 3-41 and the second water pressure sensor can be obtained by calculating the difference between the two. Here, for error considerations, the support 3-4 The measurement value of the first water pressure sensor 3-41 on the support 3-4 is determined when the monitoring component 3 is horizontal. If the measurement values ​​of the first water pressure sensors 3-41 on the four supports 3-4 are different, it means that the monitoring component 3 is tilted. The monitoring component 3 is kept horizontal by adjusting the length of the suspension rope 6. Since the distance between the first water pressure sensor 3-41 on the support 3-4 and the depth probe 3-54 is fixed at L0, the distance from the depth probe 3-54 to the mud line 5 can be calculated as L2=L′-L0 through the distance difference. The depth probe 3-54 monitors the scouring depth of the measured point by rotating a certain angle α2. The rotation angle α2 is known, and the distance from the depth probe 3-54 to the measured point is s2. The depth probe 3-54 has been measured, so the scouring depth of the measured point Δh2=s1 cosα2-L2, where if the rotation angle α2 is less than 90°, the rotation angle α2 is used when calculating the scour depth; if the rotation angle α2 is greater than 90°, the rotation angle α2-90° is used when calculating the scour depth; due to the relationship between the scour depth and time, the scour depth of each point on a certain section measured by the depth probe 3-54 through the rotation angle cannot reflect the scour depth of each point on the section at a certain moment in the actual process. Therefore, in order to make the measurement result more accurate, another depth probe 3-54 with a fixed position is set up to vertically monitor the relationship between the scour depth of the point below it and time, and the relationship function S between the scour depth and time is obtained. L =S L (t); Assuming that the time for the sounding probe 3-54 to rotate from the previous monitoring point to the next monitoring point is t, the relationship function S between the measured scour depth and time is L =S L(t), find the scour depth S3 corresponding to the time of the previous monitoring point and the scour depth S4 corresponding to the time of the next monitoring point, then β2=S4 / S3 is the rate of change of the scour depth with time, and the accurate scour depth can be calculated through the rate of change of the scour depth with time, that is, Δh′2=(s2 cosα2-L2) / β2; after the scour depths of all points at the cross section are monitored, the groove slide 3-31 at the lower part of the outer ring 3-3 drives the monitor 3-5 connected thereto to realize circumferential movement, and monitors the scour depths of all points within the circumferential range of the wind turbine foundation 1, and then transmits the scour depth monitoring data to the data receiving platform, and uses three-dimensional imaging software to perform three-dimensional imaging of the scour pit morphology;

[0072] Step 3: Dynamic scour depth monitoring during the service phase of wind turbine foundation 1: After installation, wind turbine foundation 1 begins its service process. As the service time of wind turbine foundation 1 increases, scour around the foundation continues. The scour radius of the soil around the foundation and the shape of the scour pit also change. The scour depth changes from one pile diameter to two pile diameters.

[0073] At this stage, the suspension rope is completely relaxed, and the depth of the monitoring component 3 descending reaches the limit, that is, the distance from the monitoring component 3 to the mud line 5 is fixed. In order to facilitate the explanation of the monitoring principle, the scouring depth at a certain moment is taken as an example. At this moment, the measurement value of the first water pressure sensor 3-41 on the support 3-4 in the monitoring component 3 and the measurement value of the second water pressure sensor at the mud line 5 are known. The distance L' between the first water pressure sensor 3-41 and the second water pressure sensor can be obtained by calculating the difference between the two. Here, for error considerations, the measurement value of the first water pressure sensor 3-41 on the support 3-4 is determined when the monitoring component 3 is horizontal. If the four supports 3-4 are horizontal, the distance L' between the first water pressure sensor 3-41 and the second water pressure sensor 3-4 can be obtained. If the measured values ​​of the first water pressure sensors 3-41 on the support 3-4 are different, it means that the monitoring assembly 3 is tilted. The monitoring assembly 3 is kept in a horizontal state by adjusting the length of the suspension rope 6. Since the distance between the first water pressure sensor 3-41 on the support 3-4 and the depth probe 3-54 is fixed at L0, the distance between the depth probe 3-54 and the mud line 5 can be calculated as L2=L′-L0 by the distance difference. The depth probe 3-54 monitors the scouring depth of the measured point by rotating a certain angle α3. The rotation angle α3 is known, and the distance from the depth probe 3-54 to the measured point is s3. The depth probe 3-54 has measured, so the scouring depth of the measured point Δh3=s3 cosα3-L2, where if the rotation angle α3 is less than 90°, the rotation angle α3 is used when calculating the scour depth; if the rotation angle α3 is greater than 90°, the rotation angle α3-90° is used when calculating the scour depth; due to the relationship between the scour depth and time, the scour depth of each point on a certain section measured by the depth probe 3-54 through the rotation angle cannot reflect the scour depth of each point on the section at a certain moment in the actual process. Therefore, in order to make the measurement result more accurate, another depth probe 3-54 with a fixed position is set up to vertically monitor the relationship between the scour depth of the point below it and time, and the relationship function S between the scour depth and time is obtained. L =S L (t); Assuming that the time for the sounding probe 3-54 to rotate from the previous monitoring point to the next monitoring point is t, the relationship function S between the measured scour depth and time is L =S L(t), find the scour depth S5 corresponding to the time of the previous monitoring point and the scour depth S6 corresponding to the time of the next monitoring point, then β3=S6 / S5 is the rate of change of the scour depth with time, and the accurate scour depth can be calculated through the rate of change of the scour depth with time, that is, Δh′3=(s3 cosα3-L2) / β3; after the scour depths of all points at the cross section are monitored, the groove slide 3-31 at the lower part of the outer ring 3-3 drives the monitor 3-5 connected thereto to realize circumferential movement, and monitors the scour depths of all points within the circumferential range of the wind turbine foundation 1, and then transmits the scour depth monitoring data to the data receiving platform, and uses three-dimensional imaging software to perform three-dimensional imaging of the scour pit morphology;

[0074] Step 4, monitoring of stable scour depth of wind turbine foundation 1 during service period: at this stage, the scour depth reaches equilibrium state, the scour depth is twice the pile diameter, and the change of scour depth with time is ignored. The scour pit shape tends to be stable. It is only necessary to measure the scour depth of each point at any cross section and obtain the stabilized scour pit shape. In order to facilitate the explanation of the monitoring principle, the scour depth at a certain moment is used as an example. At this moment, the measurement value of the first water pressure sensor 3-41 on the support 3-4 in the monitoring component 3 and the measurement value of the second water pressure sensor at the mud line 5 are known. The distance L' between the first water pressure sensor 3-41 and the second water pressure sensor can be obtained by calculating the difference between the two. Here, for error considerations, the water pressure sensor 3-4 on the support 3-4 is used as the reference value. The measurement value is determined when the monitoring component 3 is horizontal. If the measurement values ​​of the first water pressure sensors 3-41 on the four supports 3-4 are different, it means that the monitoring component 3 is tilted. The monitoring component 3 is kept horizontal by adjusting the length of the suspension rope 6. Since the distance between the first water pressure sensor 3-41 on the support 3-4 and the depth probe 3-54 is fixed at L0, the distance between the depth probe 3-54 and the mud line 5 can be calculated from the distance difference as L2=L′-L0. The depth probe 3-54 monitors the scour depth of the measured point by rotating a certain angle α4. The rotation angle α4 is known, and the distance between the depth probe 3-54 and the measured point is s4. The depth probe 3-54 has measured the scour depth of the measured point Δh4=s4. cosα4-L2, where if the rotation angle α4 is less than 90°, the rotation angle α4 is used when calculating the scour depth; if the rotation angle α4 is greater than 90°, the rotation angle α4-90° is used when calculating the scour depth; after the scour depths of all points at the cross section are monitored, the groove slide 3-31 at the lower portion of the outer ring 3-3 drives the monitor 3-5 connected thereto to achieve circumferential movement, and the scour depths of all points within the circumferential range of the wind turbine foundation 1 are monitored. The scour depth monitoring data is then transmitted to the data receiving platform, and three-dimensional imaging software is used to perform three-dimensional imaging of the scour pit morphology;

[0075] Step 5: Determine the scour range around the wind turbine foundation 1: As the scour depth changes, the range of the scour pit also gradually changes. How to determine the boundary of the scour pit is an extremely important step;

[0076] When the rotation angle of the depth sounding probe 3-54 is less than 90°, the problem to be solved in the area between the depth sounding probe 3-54 and the fan foundation 1 is how to determine the intersection of the fan foundation 1 and any cross section of the scour pit, that is, the maximum scour depth point of the fan foundation 1; in the process of changing the rotation angle of the depth sounding probe 3-54 from small to large, the measured distance is first the distance from the depth sounding probe 3-54 to each point in the axial direction of the fan foundation 1, and this measured distance gradually increases with the increase of the rotation angle; secondly, the measured distance is the distance from the depth sounding probe 3-54 to the point belonging to the scour pit in the area, and this measured distance gradually decreases with the increase of the rotation angle; therefore, at a certain cross section, when the rotation angle of the depth sounding probe 3-54 is less than 90°, the point with the largest measured distance is the maximum scour depth point;

[0077] When the rotation angle of the depth sounding probe 3-54 is greater than 90°, the problem to be solved in the area between the scour pit section and the mud line 5 is how to determine the intersection of the mud line 5 and any section of the scour pit, that is, the maximum scour depth radius of the wind turbine foundation 1; when the rotation angle of the depth sounding probe 3-54 changes from small to large, the distance from it to each point of the scour pit section in the area gradually increases with the increase of the rotation angle. To determine the maximum scour depth radius, it is necessary to analyze it in combination with the geometric relationship; since the vertical distance from the depth sounding probe 3-54 to the mud line 5 is known and set as Z1, the distance between the depth sounding probe 3-54 and the point to be measured is known and set as Z2, and the rotation angle of the depth sounding probe 3-54 is known and set as β, if The vertical distance from the monitoring point to the wind turbine foundation 1 is considered to be the maximum impact radius of the wind turbine foundation;

[0078] Measurement of the accumulation height on the backflow side of the fan foundation 1 when the sounding probe 3-54 moves circumferentially: During the scouring process of the fan foundation 1, soil accumulation will appear on the backflow side. The problem to be solved is how to measure the height of the accumulated soil and determine the maximum boundary of the scouring pit. The shape of the soil accumulation can be seen as an axisymmetric structure according to literature search. When the sounding probe 3-54 moves to the accumulation area to measure the scouring depth, the distance to each point within the accumulation range is uncertain. To determine the height of the accumulated soil and the maximum boundary of the scouring pit, it is necessary to combine the geometric relationship to perform Analysis; Combined with the determination of the maximum scour radius of the fan foundation, the vertical distance from this point to the sounding probe 3-54 is known and set as Z3, the vertical distance from this point to the fan foundation 1 is known and set as Z4, and the rotation angle of the sounding probe 3-54 is continued to increase to start measuring the height of the accumulated soil; since the rotation angle of the sounding probe 3-54 is known and set as γ, the distance from the sounding probe 3-54 to each point in the accumulation range is known and set as Z5, then the vertical distance between each point in the accumulation range and the sounding probe 3-54 can be calculated and set as Z6=Z5 cosγ, where the monitoring point corresponding to the minimum vertical distance Z6 between the measured point and the sounding probe 3-54 is the highest point of the accumulated soil, and the accumulation height is Z3-Z6; the horizontal distance from the maximum accumulation height point to the maximum scour radius point is known to be Z7=Z5 sinγ through geometric relationships, so the maximum boundary of the scour pit is Z4+2Z5 sinγ;

[0079] Step 6: Repair and recycling of the scour depth monitoring device: When the wind turbine foundation 1 is decommissioned or the monitoring component 3 fails, the monitoring component 3 is lifted to the sea level by lifting the rope 6 tied under the operation and maintenance platform 2, so that the entire monitoring device can be repaired and reused.

[0080] The installation method of the offshore wind turbine foundation scour depth monitoring device solves the problem that the scour depth and scour pit morphology during the installation and service of the wind turbine foundation cannot be monitored in real time and dynamically, and the scour data is inaccurate. It can accurately monitor the scour conditions during the installation and service of the wind turbine foundation, and evaluate the safety status of the wind turbine and remedy the possible lack of foundation bearing capacity in combination with the scour data. The wind turbine foundation scour depth monitoring device of the present invention can not only monitor the scour pit morphology and scour depth around the wind turbine foundation in real time during the service stage, but also monitor the scour depth of the area around the foundation during the installation process, realizing the monitoring of the scour pit morphology and scour depth during the installation and service process; at the same time, at least two water pressure sensors are used to determine the distance between the monitoring device and the mud line, and the relationship function of the scour depth change with time is obtained in combination with the installation position and rotation angle of the two depth sounding probes, and the scour depth of each point to be measured at a certain cross section is determined by geometric relationship calculation; finally, the monitoring device can be recovered or repaired during the failure stage by lifting the pull rope under the operation and maintenance platform. It has the characteristics of simplicity and convenience, accurate monitoring, real-time dynamic monitoring of the entire process, and recyclability. The corresponding construction method improves the efficiency of monitoring the scour depth and three-dimensional shape of the scour pit.

[0081] (Scooze depth monitoring and three-dimensional scour pit morphology imaging throughout the installation and service process) The monitoring component can maintain its own relative position change as the installation depth of the wind turbine foundation increases during the installation process. The scour depth of a certain monitoring point around the wind turbine foundation during the installation process can be measured by combining the difference of the water pressure sensor with the monitoring angle of the depth probe. At the same time, the relationship between the scour depth of the wind turbine foundation and time is taken into account to obtain a relationship function of the scour depth changing with time, and this function is used to correct the monitored scour depth. In addition, by analyzing the characteristic points of the scour boundary and using geometric relationships to determine the characteristic points, the scour depth monitoring of each point in the entire cross-section can be realized. At the same time, the depth probe can also make circumferential motion on the slide through the slider to realize scour depth monitoring of the 360° area around the wind turbine foundation. Finally, the monitoring data is transmitted to the data receiving platform, and the three-dimensional scour pit morphology is imaged by computer, thereby realizing scour depth detection and three-dimensional scour pit morphology imaging throughout the installation and service process.

[0082] (Geometric relationships are used to measure the scour depth at each location, ensuring accurate and reliable measurement data.) The monitoring component determines the height of the monitoring component from the mudline by analyzing the difference between the two water pressure sensors installed at the monitoring component and the mudline. Combined with the installation position of the depth probe, the height of the depth probe from the mudline is then determined. The horizontality of the monitoring component is determined by comparing the values ​​of the four water pressure sensors. The component's position is monitored in real time by pulling a rope to reduce the error in the calculated height from the depth probe to the mudline. Based on the rotation angle of the depth probe and the distance from the depth probe to the monitoring point, combined with the known height from the depth probe to the mudline, the scour depth at the monitoring point is calculated using geometric relationships. The effect of the depth probe's rotation time on the scour depth measurement is considered, and the measurement result is corrected using a function representing the change in scour depth over time. In this process, since the rotation angle of the depth probe can be accurately measured, the distance error from the depth probe to the monitoring point is controlled by the depth probe's own error accuracy, and the error in the measured height from the depth probe to the mudline is relatively small. Therefore, the error of the entire monitoring process is relatively small. Then, the circumferential movement of the sounding probe is achieved through the annular slide, and the monitoring process is repeated to complete the monitoring of the scour depth at any point in the area around the foundation and use a computer to draw the three-dimensional scour pit shape of the wind turbine foundation based on the monitored scour depth data. This process is the result of repeating the above monitoring process. Since the error of the above monitoring process is low, the overall error can also be controlled within a lower range, thereby obtaining more accurate monitoring data.

[0083] (The monitoring component can be adjusted in height, facilitating monitoring adjustments and troubleshooting.) While traditional monitoring devices are difficult to repair when they malfunction, this monitoring component can be raised and lowered using a rope installed beneath the operation and maintenance platform. Since the platform is fixed and always above sea level, if a monitoring component malfunctions, maintenance personnel can use a simple lifting device to retract the rope, raising the monitoring component to sea level for easy troubleshooting. Once the repair is complete, the rope can be released using the simple lifting device, allowing the monitoring component to descend to the predetermined monitoring position.

[0084] (The monitoring device is recyclable, saving costs) Since traditional monitoring devices have high monitoring costs, this monitoring component not only shortens the maintenance time in the event of a failure, saving a lot of maintenance costs, but also can be lifted to sea level by a simple lifting device arranged on the operation and maintenance platform after the wind turbine foundation is decommissioned, so that the entire monitoring device can be recycled and reused, greatly reducing monitoring costs.

[0085] Compared with the traditional wind turbine foundation scour depth monitoring, which has the disadvantages of inaccurate and incapable of imaging the three-dimensional scour pit morphology, high monitoring cost, and difficult maintenance in the event of a fault, the installation method of the present offshore wind turbine foundation scour depth monitoring device can maintain its own relative position change as the installation depth of the wind turbine foundation increases during the installation process. By combining the difference of the water pressure sensor with the monitoring angle of the depth sounding probe, the scour depth of a certain monitoring point around the wind turbine foundation during the installation process can be measured; at the same time, the relationship between the wind turbine foundation scour depth and time is taken into account to obtain the scour depth. A relationship function that changes with time is obtained, and this function is used to correct the monitored scour depth. In addition, by analyzing the characteristic points of the scour boundary, the method of determining the characteristic points is obtained using geometric relationships, thereby realizing scour depth monitoring of each point in the entire cross-section. At the same time, the depth probe can also make circumferential motion on the groove slide through the groove slider to realize scour depth monitoring of the 360° area around the wind turbine foundation. Finally, the monitoring data is transmitted to the data receiving platform, and the three-dimensional scour pit morphology is imaged by computer, thereby realizing scour depth detection and three-dimensional scour pit morphology imaging throughout the installation and service process. The monitoring component first determines the height of the monitoring component from the mudline using the difference in water pressure sensors. This height, combined with the installation position of the depth probe, determines the height of the depth probe from the mudline. Based on the rotation angle of the depth probe and the distance from the depth probe to the monitoring point, and the known height from the depth probe to the mudline, the scour depth at the monitoring point is calculated using geometric relationships. The scour depth at any point around the foundation is then monitored using a circular slideway. Finally, based on the monitored scour depth data, a computer is used to map the three-dimensional scour pit morphology of the wind turbine foundation. The entire monitoring process utilizes geometric relationships to generate relevant monitoring data, resulting in relatively low data errors. The scour pit morphology can be imaged throughout the entire process, facilitating real-time safety assessments of the wind turbine foundation and prompt remediation before scour damages the foundation's bearing capacity. In addition, due to the difficulties in repairing traditional monitoring devices and the high monitoring costs when they fail, the present invention uses a lifting device arranged on the operation and maintenance platform to achieve the raising and lowering of the monitoring component, which is convenient for maintenance when the monitoring component fails; at the same time, the lifting device can also be used to lift the monitoring component to sea level after the wind turbine foundation is decommissioned, and the monitoring device can be recovered and reused through hoisting, which greatly reduces the monitoring cost.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for installing an offshore wind turbine foundation scour depth monitoring device, characterized in that: The following steps are involved: Step 1, preparation before construction of the fan foundation (1): Before installing the fan foundation (1), take advantage of the fact that the inner diameter of the monitoring component (3) is larger than the outer diameter of the fan foundation (1), so that the monitoring component (3) is placed on the fan foundation (1), and the monitoring component (3) is adjusted to a suitable position. By inflating the inflatable bag (3-1), the monitoring component (3) is fixed on the outer wall of the fan foundation (1). At this stage, the position of the monitoring component (3) remains unchanged; then, the fan foundation (1) is hoisted to the guide hole of the positioning platform, and the monitoring component (3) is fixed to the operation and maintenance platform (2) by a hoisting rope; Step 2: Monitoring the scouring depth during the construction of the wind turbine foundation (1): During the installation of the wind turbine foundation (1), the air bag (3-1) is deflated to reduce its volume, so that it becomes loosely connected or disconnected from the wind turbine foundation (1), thereby preventing the monitoring component (3) and the wind turbine foundation (1) from sinking below the mud line (5). At the same time, the suspension rope (6) is loosened on the operation and maintenance platform (2) to gradually reduce the depth of the monitoring component (3). The operation is stopped when the depth reaches the limit, and the installation of the wind turbine foundation (1) is completed. During this stage, scouring occurs in the area around the wind turbine foundation (1), and the scouring depth gradually increases with the installation depth, i.e., the installation time, and the scouring depth varies from zero to one times the pile diameter. When the wind turbine foundation (1) is not installed in place: at this stage, the monitoring component (3) is gradually lowered by loosening the hanging rope (6), that is, the distance between the monitoring component (3) and the mud line (5) gradually changes as the wind turbine foundation (1) is installed. In order to facilitate the explanation of the monitoring principle, the scouring depth at a certain moment is used as an example. At this moment, the measurement value of the first water pressure sensor (3-41) on the support (3-4) of the monitoring component (3) and the measurement value of the second water pressure sensor at the mud line (5) are known. The difference between the two can be used to calculate the distance between the first water pressure sensor (3-41) and the mud line (5). 41) and the distance L between the first and second water pressure sensors. Here, for error considerations, the measurement value of the first water pressure sensor (3-41) on the support (3-4) is determined when the monitoring component (3) is horizontal. If the measurement values ​​of the first water pressure sensors (3-41) on the four supports (3-4) are different, it means that the monitoring component (3) is tilted. The monitoring component (3) is kept horizontal by adjusting the length of the suspension rope (6). Since the distance between the first water pressure sensor (3-41) on the support (3-4) and the depth probe (3-54) is fixed, , then the distance from the sounding probe (3-54) to the mudline (5) can be calculated from the distance difference as ; The depth probe (3-54) rotates a certain angle , monitor the scouring depth of the measured point, and its rotation angle Known, the distance from the sounding probe (3-54) to the point to be measured The scour depth of the point to be measured has been measured by the sounding probe (3-54). If the rotation angle is less than 90°, the rotation angle is used to calculate the scour depth. If the rotation angle is greater than 90°, the rotation angle is used to calculate the scour depth. Due to the relationship between scour depth and time, the scour depth of each point on a certain section measured by the depth probe (3-54) by rotating the angle cannot reflect the scour depth of each point on the section measured at a certain moment in the actual process. Therefore, in order to make the measurement result more accurate, another depth probe (3-54) with a fixed position is set up to vertically monitor the relationship between the scour depth of the point below it and time, and the relationship function between scour depth and time is obtained. Assuming that the time it takes for the sounding probe (3-54) to rotate from the previous monitoring point to the next monitoring point is t, the scour depth corresponding to the time of the previous monitoring point can be found by using the relationship function between the measured scour depth and time. Scour depth corresponding to the time of the next monitoring point ,So This is the rate of change of the scour depth over time. The precise scour depth can be calculated by the rate of change of the scour depth over time. After all the scour depths at the cross section are monitored, the groove slideway (3-31) at the lower portion of the outer ring (3-3) drives the monitor (3-5) connected thereto to realize circumferential movement, thereby monitoring the scour depths at various points within the circumferential range of the wind turbine foundation (1). The scour depth monitoring data is then transmitted to a data receiving platform, and three-dimensional imaging software is used to perform three-dimensional imaging of the scour pit morphology. When the wind turbine foundation is installed: at this stage, the hanging rope (6) is completely relaxed, and the depth of the monitoring component (3) reaches the limit, that is, the distance from the monitoring component (3) to the mud line (5) is fixed, and the air bag (3-1) is inflated to expand the volume of the air bag (3-1). At this time, the air bag (3-1) is in close contact with the outer wall of the wind turbine foundation (1), that is, the monitoring component (3) is fixed on the outer wall of the wind turbine foundation (1); in order to facilitate the explanation of the monitoring principle, the scouring depth at a certain moment is used as an example; at this moment, the measurement value of the first water pressure sensor (3-41) on the support (3-4) in the monitoring component (3) and the measurement value of the first water pressure sensor (3-41) at the mud line (5) are known, and the distance between the first water pressure sensor (3-41) and the second water pressure sensor can be obtained by calculating the difference between the two. Here, for error considerations, the measurement value of the first water pressure sensor (3-41) on the support (3-4) is determined when the monitoring component (3) is horizontal. If the measurement values ​​of the first water pressure sensors (3-41) on the four supports (3-4) are different, it means that the monitoring component (3) is tilted. The monitoring component (3) is kept horizontal by adjusting the length of the suspension rope (6). Since the distance between the first water pressure sensor (3-41) on the support (3-4) and the depth probe (3-54) is fixed, , then the distance from the sounding probe (3-54) to the mudline (5) can be calculated from the distance difference as ; The depth probe (3-54) rotates a certain angle , monitor the scouring depth of the measured point, and its rotation angle Known, the distance from the sounding probe (3-54) to the point to be measured The scour depth of the point to be measured has been measured by the sounding probe (3-54). , where if the rotation angle If the angle is less than 90°, the rotation angle is used to calculate the scour depth. If the rotation angle is greater than 90°, the rotation angle is used to calculate the scour depth. Due to the relationship between scour depth and time, the scour depth of each point on a certain section measured by the depth probe (3-54) by rotating the angle cannot reflect the scour depth of each point on the section measured at a certain moment in the actual process. Therefore, in order to make the measurement result more accurate, another depth probe (3-54) with a fixed position is set up to vertically monitor the relationship between the scour depth of the point below it and time, and the relationship function between scour depth and time is obtained. Assuming that the time it takes for the sounding probe (3-54) to rotate from the previous monitoring point to the next monitoring point is t, the relationship function between the measured scour depth and time is , find the scour depth corresponding to the time of the last monitoring point Scour depth corresponding to the time of the next monitoring point ,So This is the rate of change of the scour depth over time. The precise scour depth can be calculated by the rate of change of the scour depth over time. After all the scour depths at the cross section are monitored, the groove slideway (3-31) at the lower portion of the outer ring (3-3) drives the monitor (3-5) connected thereto to realize circumferential movement, thereby monitoring the scour depths at various points within the circumferential range of the wind turbine foundation (1). The scour depth monitoring data is then transmitted to a data receiving platform, and three-dimensional imaging software is used to perform three-dimensional imaging of the scour pit morphology. Step 3: Dynamic scouring depth monitoring of the wind turbine foundation (1) during its service period: The wind turbine foundation (1) begins its service period after installation. As the service time of the wind turbine foundation (1) increases, the scouring around the foundation continues, and the scouring radius of the soil around the foundation and the shape of the scouring pit also change. The scouring depth changes from one pile diameter to two pile diameters. At this stage, the rope is completely relaxed, and the depth of the monitoring component (3) reaches the limit, that is, the distance from the monitoring component (3) to the mud line (5) is fixed. In order to facilitate the explanation of the monitoring principle, the scouring depth at a certain moment is used as an example. At this moment, the measurement value of the first water pressure sensor (3-41) on the support (3-4) in the monitoring component (3) and the measurement value of the second water pressure sensor at the mud line (5) are known. The distance between the first water pressure sensor (3-41) and the second water pressure sensor can be obtained by calculating the difference between the two. Here, for error considerations, the measurement value of the first water pressure sensor (3-41) on the support (3-4) is determined when the monitoring component (3) is horizontal. If the measurement values ​​of the first water pressure sensors (3-41) on the four supports (3-4) are different, it means that the monitoring component (3) is tilted. The monitoring component (3) is kept horizontal by adjusting the length of the suspension rope (6). Since the distance between the first water pressure sensor (3-41) on the support (3-4) and the depth probe (3-54) is fixed, , then the distance from the sounding probe (3-54) to the mudline (5) can be calculated from the distance difference as ; The depth probe (3-54) is rotated by a certain angle , monitor the scouring depth of the measured point, and its rotation angle Known, the distance from the sounding probe (3-54) to the point to be measured The scour depth of the point to be measured has been measured by the sounding probe (3-54). , where if the rotation angle If the rotation angle is less than 90°, the rotation angle is used when calculating the scour depth. If it is greater than 90°, the rotation angle is used when calculating the scour depth. Due to the relationship between scour depth and time, the scour depth of each point on a certain section measured by the depth probe (3-54) by rotating the angle cannot reflect the scour depth of each point on the section measured at a certain moment in the actual process. Therefore, in order to make the measurement result more accurate, another depth probe (3-54) with a fixed position is set up to vertically monitor the relationship between the scour depth of the point below it and time, and the relationship function between scour depth and time is obtained. Assuming that the time it takes for the sounding probe (3-54) to rotate from the previous monitoring point to the next monitoring point is t, the relationship function between the measured scour depth and time is , find the scour depth corresponding to the time of the last monitoring point Scour depth corresponding to the time of the next monitoring point ,So This is the rate of change of the scour depth over time. The precise scour depth can be calculated by the rate of change of the scour depth over time. After all the scour depths at the cross section are monitored, the groove slideway (3-31) at the lower portion of the outer ring (3-3) drives the monitor (3-5) connected thereto to realize circumferential movement, thereby monitoring the scour depths at various points within the circumferential range of the wind turbine foundation (1). The scour depth monitoring data is then transmitted to a data receiving platform, and three-dimensional imaging software is used to perform three-dimensional imaging of the scour pit morphology. Step 4, monitoring of stable scour depth during the service phase of the wind turbine foundation (1): During this phase, the scour depth reaches a state of equilibrium, and the scour depth is twice the pile diameter. Ignoring the change of the scour depth over time, the scour pit shape tends to be stable. It is only necessary to measure the scour depth at each point on any cross section and obtain the stabilized scour pit shape. In order to facilitate the explanation of the monitoring principle, the scour depth at a point at a certain moment is used as an example. At this moment, the measurement value of the first water pressure sensor (3-41) on the support (3-4) in the monitoring component (3) and the measurement value of the second water pressure sensor at the mud line (5) are known. The distance between the first water pressure sensor (3-41) and the second water pressure sensor can be obtained by calculating the difference between the two. Here, for error considerations, the measurement value of the water pressure sensor (3-41) on the support (3-4) is determined when the monitoring component (3) is horizontal. If the measurement values ​​of the first water pressure sensors (3-41) on the four supports (3-4) are different, it means that the monitoring component (3) is tilted. The monitoring component (3) is kept horizontal by adjusting the length of the suspension rope (6). Since the distance between the first water pressure sensor (3-41) on the support (3-4) and the depth probe (3-54) is fixed, , then the distance from the sounding probe (3-54) to the mudline (5) can be calculated from the distance difference as The depth probe (3-54) monitors the scouring depth of the measured point by rotating a certain angle. Known, the distance from the sounding probe (3-54) to the point to be measured The scour depth of the point to be measured has been measured by the sounding probe (3-54). , where if the rotation angle If the angle is less than 90°, the rotation angle is used to calculate the scour depth. , if the rotation angle If it is greater than 90°, the rotation angle is used when calculating the scour depth. After all the scour depths at the cross section are monitored, the groove slideway (3-31) at the lower portion of the outer ring (3-3) drives the monitor (3-5) connected thereto to realize circumferential movement, thereby monitoring the scour depths at various points within the circumferential range of the wind turbine foundation (1). The scour depth monitoring data is then transmitted to a data receiving platform, and three-dimensional imaging software is used to perform three-dimensional imaging of the scour pit morphology. Step 5: (1) Determine the scour range of the surrounding area of ​​the wind turbine foundation: As the scour depth changes, the range of the scour pit also gradually changes. How to determine the boundary of the scour pit is an extremely important step; When the rotation angle of the depth sounding probe (3-54) is less than 90°, the problem to be solved in the area between the depth sounding probe (3-54) and the fan foundation (1) is how to determine the intersection of the fan foundation (1) and any cross section of the scour pit, that is, the maximum scour depth point of the fan foundation (1); in the process of changing the rotation angle of the depth sounding probe (3-54) from small to large, the measured distance is first the distance from the depth sounding probe (3-54) to each point in the axial direction of the fan foundation (1), and this measured distance gradually increases with the increase of the rotation angle; secondly, the measured distance is the distance from the depth sounding probe (3-54) to the point in the area belonging to the scour pit, and this measured distance gradually decreases with the increase of the rotation angle; therefore, at a certain cross section, when the rotation angle of the depth sounding probe (3-54) is less than 90°, the point with the largest measured distance is the maximum scour depth point; When the rotation angle of the sounding probe (3-54) is greater than 90°, the problem to be solved in the area between the scour pit section and the mud line (5) is how to determine the intersection of the mud line (5) and any section of the scour pit, that is, the maximum scour depth radius of the wind turbine foundation (1); in the process of the rotation angle of the sounding probe (3-54) changing from small to large, the distance from the sounding probe to each point of the scour pit section in the area gradually increases with the increase of the rotation angle. To determine the maximum scour depth radius, it is necessary to analyze it in combination with the geometric relationship; since the vertical distance from the sounding probe (3-54) to the mud line (5) is known and set as Z1, the distance between the sounding probe (3-54) and the point to be measured is known and set as Z2, and the rotation angle of the sounding probe (3-54) is known and set as ,like , then the vertical distance from the monitoring point to the wind turbine foundation (1) is considered to be the maximum impact radius of the wind turbine foundation; When the sounding probe (3-54) moves circumferentially, the height of the accumulation of the fan foundation (1) on the backflow side is measured: During the scouring process of the fan foundation (1), soil accumulation will appear on the backflow side. The problem to be solved is how to measure the height of the accumulated soil and determine the maximum boundary of the scouring pit. The shape of the soil accumulation is an axisymmetric structure. When the sounding probe (3-54) moves to the accumulation area to measure the scouring depth, the distance to each point within the accumulation range is uncertain. To determine the height of the accumulated soil and the maximum boundary of the scouring pit, it is necessary to analyze it in combination with geometric relationships. Combined with the determination of the maximum scouring depth radius of the fan foundation, the vertical distance from this point to the sounding probe (3-54) is known and is set as , the vertical distance from this point to the wind turbine foundation (1) is known and is set as , and the measurement of the height of the piled soil is started by continuing to increase the rotation angle of the depth probe (3-54); since the rotation angle of the depth probe (3-54) is known and is set as The distance from the sounding probe (3-54) to each point within the accumulation range is known and is set to , the vertical distance between each point in the accumulation range and the sounding probe (3-54) can be calculated and set as , where the vertical distance between the measured point and the sounding probe (3-54) The corresponding monitoring point when the minimum is the highest point of the piled soil, and the pile height is The horizontal distance from the maximum accumulation height point to the maximum punching radius point can be known from the geometric relationship , then the maximum boundary of the scour pit is ; Step 6: Repair and recycling of the scouring depth monitoring device: When the wind turbine foundation (1) is decommissioned or the monitoring component (3) fails, the monitoring component (3) is lifted to the sea level by lifting the rope (6) tied to the operation and maintenance platform (2), so as to achieve the repair and reuse of the entire monitoring device.

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