Offshore wind pile foundation monitoring system and method

Abstract

The application provides an offshore wind power pile foundation monitoring system and method, relates to the technical field of offshore wind power engineering monitoring, and comprises multiple multi-ring intelligent sensing hoops which are vertically and spacedly arranged along a pile body of an offshore wind power pile foundation, are used for measuring strain information of a circumferential position of the pile body and attitude information of the pile body, and are used for collecting multiple physical parameters in a marine environment; a relative reference module is used for measuring real-time relative deformation data between two adjacent key sections of the offshore wind power pile foundation; an absolute reference module is used for obtaining real-time absolute coordinate data of each key section; and a processing module is used for obtaining a tilt angle and a tilt direction of the offshore wind power pile foundation according to each physical parameter collection, the strain information and the attitude information, and determining an overall displacement amount of the offshore wind power pile foundation and a local bending deformation amount of each pile body section according to the real-time relative deformation data and the real-time absolute coordinate data. The above monitoring system realizes accurate measurement of deformation and tilt of the offshore wind power pile foundation.

Description

Technical Field

[0001] This application relates to the field of offshore wind power engineering monitoring technology, and in particular to an offshore wind power pile foundation monitoring system and method. Background Technology

[0002] During the service life of offshore wind power foundations, they are susceptible to the combined effects of various factors such as cyclic loads, wave currents, scouring, and soil consolidation, which can lead to problems such as uneven settlement, foundation tilting, and horizontal displacement. These problems seriously threaten the safe and stable operation of offshore wind power facilities.

[0003] Currently, existing technologies are unable to effectively distinguish the coupled deformation of the tower and the foundation when monitoring the deformation of offshore wind turbine pile foundations, resulting in monitoring data that cannot accurately reflect the true deformation and tilt of the offshore wind turbine pile foundations. Summary of the Invention

[0004] In view of this, this application proposes a monitoring system and method for offshore wind power pile foundations.

[0005] In the first aspect, this application provides an offshore wind power pile foundation monitoring system, including: multiple multi-ring intelligent sensing hoops, a relative reference module, an absolute reference module, and a processing module; Multiple multi-ring intelligent sensing hoops are arranged vertically at intervals along the pile body of the offshore wind power pile foundation. The multi-ring intelligent sensing hoops are used to measure the strain information of the circumferential position of the pile body and the attitude information of the pile body in real time, and to collect multiple physical parameters in the marine environment. The relative reference module is used to measure the real-time relative deformation data between two adjacent key sections on the offshore wind turbine pile foundation; The absolute reference module is used to locate and measure the key sections of the offshore wind power pile foundation and obtain the real-time absolute coordinate data of each key section. The processing module receives measurement information from each of the multi-ring intelligent sensing hoops, the relative reference module, and the absolute reference module. It compensates for the deformation and attitude information collected by each of the multi-ring intelligent sensing hoops based on the collected physical parameters, obtaining deformation compensation information and attitude compensation information. Based on the deformation compensation information, it obtains the principal curvature of the pile body through differential calculation. Based on the principal curvature of the pile body, it corrects the curvature integral result using the attitude compensation information as the initial value, and inverts to obtain the tilt angle and tilt direction of the offshore wind turbine pile foundation. Furthermore, it distinguishes between the overall displacement and local bending deformation of the pile body based on the real-time relative deformation data and the real-time absolute coordinate data, determining the overall displacement of the offshore wind turbine pile foundation and the local bending deformation of each pile segment.

[0006] In one embodiment, the multi-ring intelligent sensing hoop includes multiple fiber Bragg grating strain rosettes, a six-axis inertial measurement unit, and an environmental parameter measurement unit. The multiple fiber Bragg grating strain rosettes are evenly distributed circumferentially. The fiber Bragg grating strain rosettes are used to measure strain information at their arrangement positions. The six-axis inertial measurement unit is used to measure the attitude information of the pile body in real time. The environmental parameter measurement unit is used to collect multiple physical parameters in the marine environment.

[0007] In one embodiment, a temperature compensation grating is further provided on the fiber Bragg grating strain rosette, which is used to eliminate the influence of temperature changes on the strain measurement results.

[0008] In one embodiment, the relative reference module includes a sealed liquid level pipeline, a differential pressure sensing unit, and a liquid level sensing unit. The sealed liquid level pipeline is used to connect adjacent multi-ring smart sensing loops, and the sealed liquid level pipeline is filled with an inert working fluid. The differential pressure sensing unit is installed at the pipeline interface between adjacent multi-ring smart sensing loops and is used to measure the pressure difference of the working fluid at both ends of the sealed liquid level pipeline in real time. The liquid level sensing unit is used to assist in monitoring the height change of the liquid column in the sealed liquid level pipeline.

[0009] In one embodiment, a temperature expansion compensation cavity is also provided on the sealed liquid level pipeline, which is used to buffer the volume expansion of the inert working fluid caused by temperature changes.

[0010] In one embodiment, the absolute reference module includes a seabed local reference array and a plurality of acoustic long baseline transponders. The seabed local reference array includes a plurality of reference piles, which are arranged circumferentially along the offshore wind turbine pile foundation in a polygonal topological distribution. Each acoustic long baseline transponder is respectively disposed on each of the reference piles.

[0011] In one embodiment, when the soil stiffness of the seabed area where the offshore wind turbine pile foundation is located is greater than a preset threshold, the local seabed reference array is set within a ring within a range of 1–2D from the pile foundation, where D is the diameter of the offshore wind turbine pile foundation. When the soil stiffness of the seabed area where the offshore wind turbine pile foundation is located is not greater than a preset threshold, the local seabed reference array is set within a ring within a range of 3–5D from the pile foundation.

[0012] In one embodiment, the processing module is further configured to determine the absolute coordinate change of each key section based on the real-time absolute coordinate data of each key section; if the absolute coordinate change of all key sections is consistent, it is determined that the pile foundation has an overall displacement; the theoretical relative displacement between adjacent key sections is determined based on the real-time absolute coordinate data of each key section; the theoretical relative displacement between adjacent key sections is compared with the real-time relative deformation data obtained by the relative reference module; if the comparison deviation is not greater than a preset error threshold, it is confirmed that the pile foundation has an overall displacement and no local bending deformation has occurred, and the overall displacement is the absolute coordinate change of any one key section.

[0013] In one embodiment, the processing module is further configured to determine that there is local bending deformation in the target pile segment between adjacent key sections when the absolute coordinate changes of adjacent key sections are not synchronized; calculate the difference in absolute coordinate changes of adjacent key sections based on the real-time absolute coordinate data of each key section as the theoretical local bending deformation; obtain the real-time relative deformation data of adjacent key sections measured by the relative reference module; compare the theoretical local bending deformation with the real-time relative deformation data; and determine the local bending deformation or the real-time relative deformation data as the actual local bending deformation of the target pile segment when the theoretical local bending deformation is the same as the real-time relative deformation data.

[0014] Secondly, this application also provides a method for monitoring offshore wind turbine foundation piles, which is performed based on the offshore wind turbine foundation pile monitoring system as described in the first aspect; the offshore wind turbine foundation pile monitoring method includes: Receive measurement information from each of the multi-ring intelligent sensing loops, the relative reference module, and the absolute reference module; The deformation and attitude information collected by each multi-ring smart sensor hoop are compensated based on the collected physical parameters to obtain deformation compensation information and attitude compensation information. Based on the deformation compensation information, the principal curvature of the pile body is obtained through differential calculation; Based on the principal curvature of the pile body, the curvature integral result is corrected using the attitude compensation information as the initial value, and the tilt angle and tilt direction of the offshore wind power pile foundation are obtained by inversion. Based on the real-time relative deformation data and the real-time absolute coordinate data, the overall displacement of the pile body and the local bending deformation of each pile body segment are distinguished, and the overall displacement of the offshore wind power pile foundation and the local bending deformation of each pile body segment are determined.

[0015] The offshore wind turbine foundation monitoring system proposed in this application has the following advantages over related technologies: 1. The offshore wind power pile foundation monitoring system of this application includes multiple multi-ring intelligent sensing hoops, a relative reference module, an absolute reference module, and a processing module. By arranging multiple multi-ring intelligent sensing hoops vertically at intervals along the pile body, it can capture the circumferential strain and attitude information of the pile body in real time, and also collect multiple marine environmental physical parameters, providing basic support for subsequent data compensation. On this basis, after receiving multi-source measurement information, the processing module uses marine environmental physical parameters to compensate for deformation and attitude information, and then obtains the principal curvature of the pile body through differential calculation. Using the compensated attitude information as the initial value, the curvature integral result is corrected, which can accurately invert the pile foundation tilt angle and tilt direction, and realize accurate measurement of the clear condition of the offshore wind power pile foundation.

[0016] 2. The relative reference module can accurately measure the real-time relative deformation data of adjacent key sections, while the absolute reference module can acquire the real-time absolute coordinate data of each key section. The two together form a dual-reference calibration framework. Based on this, after receiving multi-source measurement information, the processing module effectively distinguishes between the overall displacement and local bending deformation of the pile body based on the relative deformation data and the absolute coordinate data. It clarifies the overall displacement and the local bending deformation of each pile section, ultimately achieving stable and accurate monitoring of the absolute settlement, horizontal displacement, and local deformation of the pile foundation under complex sea conditions and temperature and pressure variations. Furthermore, the offshore wind power pile foundation monitoring system of this application supports full life-cycle application from construction to operation, and features sea condition resistance, low power consumption, and convenient operation and maintenance, providing reliable data support for the safe and stable operation of offshore wind power pile foundations. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the application environment of the offshore wind power pile foundation monitoring system in one embodiment of this application; Figure 2 This is a schematic diagram of the structure of an offshore wind power pile foundation monitoring system in one embodiment of this application; Figure 3 This is a schematic diagram of the structure of a multi-ring smart sensing hoop in one embodiment of this application; Figure 4 This is a schematic diagram of the principle of the relative reference module in one embodiment of this application; Figure 5 This is a top view of the arrangement of a local reference array on the seabed in one embodiment of this application; Figure 6 This is a top view of the arrangement of the absolute reference module in one embodiment of this application; Figure 7 This is an example diagram showing the deformation results of wind turbine jacket pile foundation monitoring in one embodiment of this application; Figure 8 This is a flowchart illustrating a method for monitoring offshore wind power pile foundations in one embodiment of this application.

[0019] Explanation of reference numerals in the attached figures: 1-Offshore wind turbine pile foundation; 2-Multi-ring intelligent sensing hoop; 21-Fiber Bragg grating strain rosette; 22-Six-axis inertial measurement unit; 23-Environmental parameter measurement unit; 24-Sealed housing; 25-Data acquisition unit; 3-Seabed local reference array; 31-Reference pile; 32-Settlement gauge; 33-Porous manometer; 34-Reflection marker; 4-Relative reference module; 41-Sealed liquid level pipeline; 42-Inert working fluid; 43-Differential pressure sensing unit; 44-Temperature expansion compensation cavity; 5-Absolute reference module; 51-Acoustic long baseline transponder; 52-Anchoring device; 6-Submarine cable fiber optic; 7-Energy module; 8-Communication module; 9-Processing module; 10-Shore station digital twin platform; 11-Wind turbine SCADA system. Detailed Implementation

[0020] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] In some embodiments, such as Figure 1 As shown, Figure 1 and Figure 2 As shown, this application provides a monitoring system for offshore wind turbine foundation piles 1, comprising: multiple multi-ring intelligent sensing hoops 2, a relative reference module 4, an absolute reference module 5, and a processing module 9. It should be noted that... Figure 1 This is an example diagram of the application environment of the offshore wind power pile foundation 1 monitoring system. The multi-ring intelligent sensing hoop 2, the relative reference module 4 and the absolute reference module 5 are connected to the processing module 9, the shore station digital twin platform 10 and the wind turbine SCADA system 11 through the submarine cable fiber optic 6 and the energy module 7. The energy module 7 provides power to the corresponding modules.

[0022] Multiple multi-ring intelligent sensor hoops 2 are vertically spaced along the pile body of the offshore wind turbine pile foundation 1. The multi-ring intelligent sensor hoops 2 are used to measure the strain information and attitude information of the pile body in real time along its circumferential position, and to collect multiple physical parameters in the marine environment. The number of multi-ring intelligent sensor hoops 2 can be 3-4, and through reasonable vertical spacing, it is ensured that deformation information at different positions of the pile body can be comprehensively captured.

[0023] The relative reference module 4 is used to measure the real-time relative deformation data between two adjacent key sections on the offshore wind turbine pile foundation 1. By deploying high-precision measurement units in pairs at key sections of the pile foundation where stress is concentrated and deformation is prone to occur (such as the top of the pile, the middle section and the connection with the foundation), the real-time relative changes in spatial position between two adjacent key sections can be accurately captured. The measured real-time relative deformation data can cover the relative linear displacement, relative angular displacement and relative strain distribution differences between the two sections. These data directly reflect the degree of local deformation between adjacent key sections.

[0024] The absolute reference module 5 is used to locate and measure the key sections of the offshore wind turbine pile foundation 1, and obtain the real-time absolute coordinate data of each key section. By deploying high-precision positioning units adapted to the marine environment for the key sections of the pile foundation that are critical to stress and sensitive to deformation, the real-time three-dimensional absolute coordinate data of each key section in a unified global coordinate system can be accurately captured. These data directly reflect the absolute spatial position of each key section, which not only overcomes the limitation of the relative reference module 4, which can only capture local relative deformation and cannot reflect the overall spatial displacement of the pile body, but also provides a unified global positioning benchmark for the entire monitoring system. It can also form a complementary verification with the local relative deformation data of the relative reference module 4, helping the processing module 9 to clearly define the overall displacement and local bending deformation of the pile foundation, and avoid monitoring errors caused by confusing the two types of deformation.

[0025] The processing module 9 receives measurement information from each multi-ring intelligent sensing hoop 2, relative reference module 4, and absolute reference module 5. It compensates for the deformation and attitude information collected by each multi-ring intelligent sensing hoop based on the collected physical parameters, and obtains deformation compensation information and attitude compensation information. Based on the deformation compensation information, it obtains the principal curvature of the pile body through differential calculation. Based on the principal curvature of the pile body, it corrects the curvature integral result with the attitude compensation information as the initial value, and inverts to obtain the tilt angle and tilt direction of the offshore wind power pile foundation 1. Based on the real-time relative deformation data and real-time absolute coordinate data, it distinguishes between the overall displacement and local bending deformation of the pile body, and determines the overall displacement and local bending deformation of each pile segment of the offshore wind power pile foundation 1.

[0026] It is understandable that the processing module 9 can simultaneously receive the circumferential strain and attitude information of the pile body transmitted by multiple multi-ring intelligent sensing hoop 2, as well as multiple physical parameters of the marine environment, the real-time relative deformation data of adjacent key sections output by the relative reference module 4, and the real-time absolute coordinate data of each key section obtained by the absolute reference module 5, to construct a multi-dimensional, full-view original data matrix, providing complete data support for subsequent analysis. Then, considering that physical factors such as temperature and pressure changes and water flow disturbances in the marine environment can easily interfere with the deformation and attitude information collected by the multi-ring intelligent sensing hoop 2, resulting in deviations in the original data, the processing module 9 uses the collected physical parameters as a basis to perform targeted correction on the deformation and attitude information through a preset environmental compensation algorithm, eliminating the systematic errors caused by environmental interference, and obtaining accurate deformation compensation information and attitude compensation information, laying a reliable data foundation for subsequent calculations.

[0027] If temperature changes cause zero-bias errors in the sensor, the system will correct the measurement data through a temperature compensation model, and the final output of pile settlement and horizontal displacement values ​​will meet the predetermined accuracy requirements. Physical quantity compensation in the monitoring data processing method can include strain compensation, liquid level differential pressure compensation, and temperature drift compensation. A multi-parameter compensation model is established to address the impact of temperature, pressure, and salinity changes in the marine environment on the sensor.

[0028] In the multi-physical quantity compensation (MPC) system for temperature, pressure, and salt, strain compensation is achieved by constructing a fiber Bragg grating (FBG) wavelength-temperature-pressure sensitive matrix. Environmental parameters are acquired in real time using temperature / external water pressure sensors, and the matrix equation corrects the strain measurements. The key to strain compensation in this system lies in utilizing the sensitivity of the FBG wavelength to temperature and pressure changes. Specifically, the FBG senses changes in strain, temperature, and pressure through variations in the reflected wavelength. When the ambient temperature or pressure changes, the reflected wavelength of the FBG changes, and the system corrects the strain data based on these changes.

[0029] Suppose we use fiber Bragg grating sensors to measure the strain of an offshore wind turbine foundation (1) in a monitoring system. The reflected wavelength of the fiber Bragg grating is a specific value when there are no external influences. Then, suppose the temperature changes, increasing by 5°C, while the external water pressure increases by 2 MPa. Both of these factors will cause the reflected wavelength of the fiber Bragg grating to change, therefore the system needs to correct the strain value according to the changes in temperature and pressure.

[0030] Based on temperature-wavelength sensitivity (e.g., the amount of wavelength change per degree Celsius), the system can calculate the impact of temperature changes on strain measurements using a sensitivity matrix and correct the strain values. Similarly, changes in external water pressure also affect the wavelength of the fiber Bragg grating; therefore, the system corrects for errors caused by pressure changes using a pressure-wavelength sensitivity matrix. Through this matrix equation, the system can correct the strain data of the fiber Bragg grating sensor based on real-time temperature and external water pressure data. Ultimately, the temperature compensation accuracy can reach ≤0.5 με / ℃; the pressure compensation accuracy can reach ≤0.1 με / MPa. This compensation ensures that the strain measurement of the fiber Bragg grating sensor remains highly accurate even in marine environments with significant temperature and pressure variations.

[0031] Subsequently, based on the corrected deformation compensation information, the principal curvature of the pile body is accurately obtained using the differential calculation method. This principal curvature directly reflects the degree and characteristics of bending in various parts of the pile body and is the core indicator for analyzing the deformation morphology of the pile body. On this basis, the processing module 9 uses the attitude compensation information as the initial boundary condition to perform integral calculation on the principal curvature of the pile body. At the same time, the initial value is corrected to avoid the accumulation and amplification of errors during the integration process. Finally, the tilt angle and tilt direction of the offshore wind power pile foundation 1 are accurately inverted, clearly presenting the overall attitude offset state of the pile foundation.

[0032] It should be noted that the curvature and tilt angle inversion algorithm is based on the Euler-Bernoulli beam theory, treating the pile as an elastic beam. It utilizes circumferential strain data collected by multi-ring intelligent sensing hoops to obtain the principal curvature of the pile through differential calculation. The pile radius is defined as c, the strain difference between the upper and lower surfaces (along the pile radial direction) as Δε, and the principal curvature κ≈Δε / (2c). Using circumferential multi-angle strain data, the curvatures κx and κy in the two orthogonal directions x and y are calculated. Combined with the pile length parameter, the bending shape of the pile axis is obtained through integration. Simultaneously, using attitude compensation information (quaternion attitude data) as initial values, the gravitational component and high-frequency dynamic acceleration interference are subtracted to correct the curvature integral result, ultimately inverting to obtain the tilt angle (accuracy ≤0.01°) and tilt direction of the pile foundation.

[0033] Finally, the processing module 9 can perform collaborative analysis on the real-time relative deformation data of the relative reference module 4 and the real-time absolute coordinate data of the absolute reference module 5. By comparing the correlation between the global absolute position change and the local relative deformation, it can accurately distinguish between the overall displacement of the pile body and the local bending deformation, and then quantitatively calculate the overall displacement of the pile foundation and the local bending deformation of each pile segment. The entire processing process not only achieves accurate correction of single-source data, but also breaks through the limitations of a single data dimension through the collaborative fusion of multi-source data, ensuring the calculation accuracy of core monitoring parameters such as tilt angle, overall displacement, and local bending deformation.

[0034] The aforementioned monitoring system for offshore wind turbine pile foundation 1 includes multiple multi-ring intelligent sensing hoops 2, a relative reference module 4, an absolute reference module 5, and a processing module 9. By arranging the multiple multi-ring intelligent sensing hoops 2 vertically at intervals along the pile body, it can capture the circumferential strain and attitude information of the pile body in real time, and also collect multiple marine environmental physical parameters, providing basic support for subsequent data compensation. Based on this, the processing module 9 receives multi-source measurement information, compensates for deformation and attitude information using marine environmental physical parameters, and then obtains the principal curvature of the pile body through differential calculation. Using the compensated attitude information as the initial value, the curvature integral result is corrected, which can accurately invert the pile foundation tilt angle and tilt direction, and achieve accurate measurement of the clear condition of the offshore wind turbine pile foundation 1. The relative reference module 4 can accurately measure the real-time relative deformation data of adjacent key sections, and the absolute reference module 5 can obtain the real-time absolute coordinate data of each key section. The two construct a dual-reference calibration framework. Based on this, after receiving multi-source measurement information, the processing module 9 effectively distinguishes between the overall displacement and local bending deformation of the pile body based on relative deformation data and absolute coordinate data, and clarifies the overall displacement and the local bending deformation of each pile body segment. Ultimately, it achieves stable and accurate monitoring of the absolute settlement, horizontal displacement and local deformation of the pile foundation under complex sea conditions and temperature and pressure changes. Furthermore, the offshore wind power pile foundation 1 monitoring system of this application supports full life cycle application from construction period to operation period, and has the characteristics of sea condition resistance, low power consumption and convenient operation and maintenance, providing reliable data support for the safe and stable operation of the offshore wind power pile foundation 1.

[0035] In some embodiments, such as Figure 3 As shown, the multi-ring intelligent sensing hoop 2 includes multiple fiber Bragg grating strain gauges 21, a six-axis inertial measurement unit 22, and an environmental parameter measurement unit 23. The multiple fiber Bragg grating strain gauges 21 are evenly distributed circumferentially. The fiber Bragg grating strain gauges 21 are used to measure strain information at their arrangement positions. The six-axis inertial measurement unit 22 is used to measure the attitude information of the pile body in real time. The environmental parameter measurement unit 23 is used to collect multiple physical parameters in the marine environment. The measurement data from the fiber Bragg grating strain gauges 21, the six-axis inertial measurement unit 22, and the environmental parameter measurement unit 23 can be acquired by the data acquisition unit 25 and then transmitted to the processing module 9.

[0036] The fiber Bragg grating strain gauge 21 can be four in number, arranged at angles of 0° / 90° / 180° / 270°. To achieve shear / asymmetric compensation, the number of fiber Bragg grating strain gauges 21 can be increased, with additional arrangement angles of 45° / 135°. The measurement range of the fiber Bragg grating strain gauge 21 can be ±3000με, with a resolution not exceeding 1με. The six-axis inertial measurement unit 22 integrates a three-axis gyroscope and a three-axis accelerometer, with a zero-bias drift of no more than 3° / h, and provides gravity reference attitude estimation, enabling real-time acquisition of the pile's attitude information.

[0037] The environmental parameter measurement unit 23 may include temperature, external water pressure and salinity sensing units. The temperature sensing unit has a measurement accuracy of ±0.05℃, the external water pressure measurement range is 0–5MPa, and the salinity can be calculated from the conductivity.

[0038] The multi-ring intelligent sensing hoop 2 can be made of duplex stainless steel or titanium alloy to form a sealed housing 24 with a protection level of IP68 / 300m, which can effectively resist the corrosion of seawater and the influence of high pressure environment; the surface of the housing is coated with epoxy and anti-fouling coating to further enhance corrosion resistance and prevent marine organisms from attaching, ensuring long-term stable operation of the sensor.

[0039] In this embodiment, multiple fiber Bragg grating strain gauges 21 are arranged in a circumferentially uniform manner, which not only fully adapts to the cylindrical structure of the pile but also ensures that strain information at each arrangement position is captured from all angles around the pile without any blind spots. These strain gauges possess characteristics such as resistance to electromagnetic interference, resistance to seawater corrosion, and high measurement accuracy. The six-axis inertial measurement unit 22 can sense the dynamic attitude of the pile in real time and accurately output the pile's real-time tilt angle, angular velocity, acceleration, and other attitude information, directly reflecting the pile's tilt trend and motion state. The accompanying environmental parameter measurement unit 23 is specifically designed for the complexity of the marine environment, directionally collecting multiple key physical parameters such as temperature, pressure, water flow velocity, and salinity. These parameters are the core factors causing environmental interference errors in pile strain and attitude measurements, providing accurate environmental correction basis for subsequent processing module 9 to perform deformation and attitude information compensation.

[0040] In some embodiments, a temperature compensation grating is also provided on the fiber Bragg grating strain flower 21, which is used to eliminate the influence of temperature changes on the strain measurement results.

[0041] In applications, temperature fluctuations in the marine environment (such as diurnal temperature range and seasonal changes) can easily interfere with fiber Bragg grating strain measurements. Furthermore, since the center wavelength offset of the fiber Bragg grating is affected by both strain and temperature changes, if data is obtained solely through the strain measurement grating, the wavelength offset caused by temperature will be misinterpreted as a strain signal, leading to significant deviations in the strain measurement results. The temperature compensation grating, using the same material and packaging process as the strain measurement grating and placed on the same strain rose carrier, is placed in the same temperature environment as the strain measurement grating. It can then be installed in a special way (such as non-stressed bonding or independent suspended placement) without bearing the strain of the pile body, only synchronously sensing temperature changes and generating wavelength shifts caused purely by temperature. During operation, the temperature compensation grating and the strain measurement grating synchronously acquire real-time wavelength data. The processing module 9 compares the wavelength shift difference between the two, uses a preset temperature-wavelength calibration model to separate the wavelength change caused by pure temperature factors, and then removes this temperature-affected component from the total wavelength shift of the strain measurement grating. Finally, it accurately extracts the strain signal caused solely by the deformation of the pile body under stress, completely eliminating the interference of temperature changes on the strain measurement results.

[0042] In some embodiments, such as Figure 4 As shown, the relative reference module 4 includes a closed liquid level pipeline 41, a differential pressure sensing unit 43, and a liquid level sensing unit. The closed liquid level pipeline 41 is used to connect adjacent multi-ring intelligent sensing clamps 2, and the closed liquid level pipeline 41 is filled with inert working fluid 42. The differential pressure sensing unit 43 is installed at the pipeline interface between adjacent multi-ring intelligent sensing clamps 2 and is used to measure the working fluid pressure difference at both ends of the closed liquid level pipeline 41 in real time. The liquid level sensing unit is used to assist in monitoring the height change of the liquid column in the closed liquid level pipeline 41.

[0043] Among them, the inert working fluid 42 has the characteristics of stable density and calibrable thermal expansion coefficient.

[0044] The relative reference module 4 is based on "closed liquid column conduction + multi-parameter compensation". It is connected by a vertically spaced multi-ring intelligent sensing clamp 2 through a closed liquid level pipeline 41. The filling density in the pipeline is stable (0.95-0.98 g / cm³ at 20℃, temperature density coefficient ≤1×10). -4 An inert working fluid 42 (such as PDMS silicone oil) with a calibrable coefficient of thermal expansion (g / (cm³·℃)) is used to transmit the height difference at different sensing points by utilizing the incompressible properties of the liquid.

[0045] In the relative reference module 4, the differential pressure sensing unit 43 is installed at the pipeline interface of the adjacent multi-ring intelligent sensing hoop 2 to measure the pressure difference of the working fluid at both ends in real time; the liquid level sensing unit assists in monitoring the change of liquid column height in the pipeline, and combined with the current density of the working fluid (after temperature drift compensation), calculates the relative settlement of the adjacent sensing hoop using the formula ΔS=ΔP / (ρ×g) (ΔS is the relative settlement, ΔP is the pressure difference, ρ is the working fluid density, and g is the gravitational acceleration), and then splices out the local deformation curve of the pile body from the top to the bottom, accurately capturing deformation characteristics such as pile body bending and uneven settlement.

[0046] The relative reference module 4 ensures data reliability by employing a closed pipeline to prevent seawater infiltration and contamination, ensuring stable working fluid performance. Simultaneously, cross-validation between the differential pressure sensing unit 43 and the liquid level sensing unit improves the accuracy of the relative sedimentation calculation (error ≤ 0.1mm). The cross-validation between the differential pressure sensing unit 43 and the liquid level sensing unit is based on the principle that "there is a physical correlation between the pressure difference of the working fluid and the change in liquid column height within the same closed pipeline." Verification is achieved through bidirectional data conversion and comparison, as detailed below:

[0047] A physical correlation model is established: Based on the principles of fluid statics, the pressure difference ΔP measured by the differential pressure sensing unit 43, the change in liquid column height Δh measured by the liquid level sensing unit, the working fluid density ρ after temperature drift compensation, and the gravitational acceleration g satisfy the fixed correlation formula: ΔP = ρ·g·Δh (ignoring the slight frictional resistance along the pipeline). This model provides a theoretical basis for cross-validation of the two sets of data.

[0048] On one hand, the theoretical pressure difference is deduced from the data of the liquid level sensing unit: the Δh collected in real time by the liquid level sensing unit is substituted into the above formula to calculate the "theoretical ΔP", and compared with the "actual ΔP" measured by the differential pressure sensing unit 43. If the deviation between the two is within the preset threshold (such as the pressure difference corresponding to ≤0.05mm), then both sets of data are determined to be valid. On the other hand, the theoretical liquid column height is deduced from the data of the differential pressure sensing unit 43: the "theoretical Δh" is calculated from the ΔP measured by the differential pressure sensing unit 43 using the formula Δh=ΔP / (ρ·g), and compared with the "actual Δh" measured by the liquid level sensing unit, thus verifying whether the deviation meets the requirements.

[0049] Finally, abnormal data is identified and corrected: if the deviation after bidirectional conversion exceeds the threshold, the system will prioritize eliminating abnormal data based on the sensor's own status, or use the weighted average of the two valid data as the final calculation basis to avoid errors caused by a single sensor failure. Through the above bidirectional verification of "measured value - theoretical value", the two sets of data are mutually verified, eliminating the influence of random errors or drift from a single sensor, and ensuring the accuracy of the relative settlement calculation.

[0050] In some embodiments, a temperature expansion compensation chamber 44 is also provided on the closed liquid level pipeline 41. The temperature expansion compensation chamber 44 is used to buffer the volume expansion of the inert working fluid 42 caused by temperature changes.

[0051] The temperature expansion compensation chamber 44 has a volume of 1000-1500 mL and can be made of borosilicate glass. Combined with corrected measurement values, the temperature expansion compensation chamber 44 can avoid spurious settling caused by temperature fluctuations (compensation accuracy ≤0.1 mm / ℃). The temperature drift model can be based on an experimentally calibrated temperature-density curve.

[0052] Temperature drift compensation is achieved by combining the current detection temperature with the characteristics of the working fluid itself. By correcting the impact of temperature changes on the working fluid density in real time, it ensures the accuracy of the calculation results related to pressure difference and liquid column height. The characteristics of the working fluid itself can include properties such as the coefficient of thermal expansion and viscosity-temperature sensitivity.

[0053] In thermo-pressure salt multi-physical quantity compensation, liquid level differential pressure compensation can be based on experimental data of the thermal expansion coefficient of the inert working fluid 42 to establish a liquid level density-temperature function. This function, combined with the volume change of the thermal expansion compensation chamber 44, corrects the measured value of the differential pressure sensing unit 43, eliminating spurious sedimentation caused by temperature (compensation accuracy ≤ 0.1 mm / ℃). The core of liquid level differential pressure compensation is to establish the relationship between liquid level density and temperature (liquid level density-temperature function) and combine it with the thermal expansion coefficient of the inert working fluid 42 to correct the measured value of the differential pressure sensing unit 43. The liquid level differential pressure sensing unit 43 is typically used to measure the height difference of liquids, and the density of the liquid usually changes with temperature, thus affecting the measurement results.

[0054] For example, suppose we use a differential pressure level sensor unit 43 to monitor liquid level changes in the monitoring system of an offshore wind turbine foundation 1. This sensor calculates the liquid level height by measuring the pressure difference across the liquid level. However, in a marine environment, the temperature of the liquid fluctuates with seasonal or weather changes, and these temperature changes cause changes in the liquid density, thus affecting the measurement accuracy of the level sensor unit. For instance, when the liquid temperature increases by 10°C, the liquid density may change slightly, causing errors in the pressure difference measured by the level sensor unit. Without compensation, the change in liquid level may not be caused by actual physical deformation, but rather by density changes due to temperature variations.

[0055] To address this issue, the system utilizes the thermal expansion coefficient data of the inert working fluid 42 to establish a liquid level density-temperature function. This function calculates the liquid density based on the current temperature and corrects the measured value of the liquid level sensing unit by incorporating the thermal expansion characteristics of the liquid volume. The thermal expansion compensation chamber adjusts the liquid volume change when the temperature changes, thereby eliminating the influence of temperature changes on the liquid level. Through this compensation, the system can accurately measure liquid level changes, eliminate spurious settlement caused by temperature variations, and ensure the accuracy of settlement and displacement data.

[0056] Temperature drift compensation in thermo-pressure salt multi-physical quantity compensation is achieved by collecting the ambient temperature through a temperature sensor and using a preset temperature drift model (quadratic polynomial model) to correct the zero bias error of the gyroscope and accelerometer. After compensation, the zero bias drift is ≤1° / h.

[0057] In some embodiments, such as Figure 5 and Figure 6 As shown, the absolute reference module 5 includes a seabed local reference array 3 and multiple acoustic long baseline transponders 51. The seabed local reference array 3 includes multiple reference piles 31, which are arranged circumferentially along the offshore wind power pile foundation 1 in a polygonal topological distribution. Each acoustic long baseline transponder 51 is respectively set on each reference pile 31.

[0058] In applications, the seabed local reference array 3 can be arranged with 3-4 reference piles 31 in a 1-5 D ring at a distance of 120° or 90° from the pile foundation. The reference piles 31 serve as the supporting foundation for the acoustic long baseline transponder 51. A vibrating wire or fiber optic settlement gauge 32 and a pore pressure gauge 33 can also be mounted on the reference piles 31, and an acoustic or optical reflection marker 34 is set on the top of the pile. Considering the positioning accuracy requirements of the acoustic long baseline measurement technology, the coverage requirements of the monitoring area, and the economic efficiency of the project, the number of transponders can be 3-6. Further, it can be 3-4.

[0059] The absolute reference module 5 in the monitoring system is constructed based on acoustic long baseline measurement technology. Its core component is the deployment of acoustic long baseline transponders 51 within a 200–600m radius around the pile foundation. The preferred number of transponders is four, arranged in an equilateral triangle or square topology to form an acoustic long baseline measurement network covering the monitoring area. Before deploying the acoustic long baseline measurement network, the locations must be optimized based on seabed topography, water flow velocity, and acoustic signal propagation characteristics to prevent transponders from being eroded or buried, or located in areas with signal obstruction. Furthermore, the spacing between adjacent transponders must meet the acoustic ranging accuracy requirements (usually not less than 100m) to ensure the stability of the measurement network's geometric configuration.

[0060] The core of the equilateral triangle topology is "three main transponders forming an equilateral triangle baseline network, and one auxiliary transponder optimizing the geometric configuration". The specific deployment logic is as follows: First, select three transponders (denoted as A, B, and C) and distribute them according to the vertices of the equilateral triangle, deploying them within a range of 200–600m around the pile foundation. Ensure that the radius of the circumcircle of the equilateral triangle covers the entire pile foundation monitoring area (i.e., the pile foundation is located inside the circumcircle of the equilateral triangle), and that the distances of points A, B, and C from the pile foundation are approximately equal, ensuring uniform positioning accuracy in all directions. The fourth transponder (denoted as D) is deployed on the "extension line connecting the centroid of the equilateral triangle to any vertex" (or at the intersection of the inscribed circle of the equilateral triangle and a certain median), and the distances of point D from points A, B, and C do not exceed the deployment range of 200–600m. Point D, acting as an auxiliary transponder, can form new measurement baselines (such as AD, BD, and CD) with points A, B, and C respectively. This increases the number of baselines and the cross-validation dimension, optimizes the geometric strength of the measurement network, further improves the accuracy and reliability of absolute coordinate calculation, and avoids monitoring blind spots caused by a single baseline failure. In short, the equilateral triangle topology of the four transponders is not a "regular tetrahedron," but rather a configuration of "equilateral triangle baseline network + internal / extension auxiliary points." This retains the uniform coverage advantage of the equilateral triangle layout while enhancing the stability and accuracy of the monitoring network by adding auxiliary points.

[0061] In some embodiments, when the soil stiffness of the seabed area where the offshore wind turbine pile foundation 1 is located is greater than a preset threshold, the seabed local reference array 3 is set in a ring within a range of 1–2D from the pile foundation 1, where D is the diameter of the offshore wind turbine pile foundation 1.

[0062] When the soil stiffness of the seabed area where the offshore wind turbine pile foundation 1 is located is not greater than a preset threshold, the local reference array 3 of the seabed is set in a ring within a range of 3–5D from the pile foundation.

[0063] Setting the local seabed reference array 3 near the pile side (1–2D) is suitable for areas with high seabed soil stiffness (such as dense sand layers and hard clay layers). This reduces the indirect impact of pile foundation deformation on the reference pile 31, while ensuring consistency in geological conditions between the two and avoiding reference deviations caused by soil layer differences. Setting the local seabed reference array 3 far from the pile side (3–5D) is suitable for soft soil foundations (such as silty clay and loose silt layers). In this case, it is necessary to increase the spacing to avoid disturbance of the soil around the reference pile 31 by cyclic loads during pile foundation construction and operation. At this time, reinforcement measures need to be set at the bottom of the reference pile 31 simultaneously to ensure vertical stability.

[0064] The 120° fan-shaped arrangement (3 reference piles 31) in the seabed local reference array 3 is suitable for circular pile foundations. The 3 reference piles 31 are distributed in an equilateral triangle, which can cover the 360° monitoring range around the pile foundation. The line connecting any two reference piles 31 can form a verification baseline, which meets the requirements for in-plane horizontal displacement and tilt angle calibration. The 90° fan-shaped arrangement (4 reference piles 31) is suitable for rectangular or polygonal foundations (such as jacket foundations). The 4 reference piles 31 are distributed along the diagonal of the foundation, which can specifically cover the deformation-sensitive area of ​​the foundation corners, and at the same time provide denser calibration points for horizontal displacement (X / Y bidirectional), which is especially suitable for sea areas with significant horizontal loads.

[0065] In some embodiments, the processing module 9 is further configured to determine the absolute coordinate change of each key section based on the real-time absolute coordinate data of each key section; if the absolute coordinate change of all key sections is consistent, it is determined that the pile foundation has an overall displacement; the theoretical relative displacement between adjacent key sections is determined based on the real-time absolute coordinate data of each key section; the theoretical relative displacement between adjacent key sections is compared with the real-time relative deformation data obtained by the relative reference module 4; if the comparison deviation value is not greater than the preset error threshold, it is confirmed that the pile foundation has an overall displacement and no local bending deformation has occurred; the overall displacement is the absolute coordinate change of any one key section.

[0066] It is understandable that processing module 9, based on the real-time absolute coordinate data of each key section continuously output by absolute reference module 5, calculates the coordinate difference of the same key section at different monitoring times to obtain the absolute coordinate change of each key section. This change directly reflects the global spatial displacement amplitude and direction of a single key section. Since if the pile foundation undergoes overall displacement, its key sections will exhibit synchronous and unidirectional rigid body motion characteristics, when the absolute coordinate changes of all key sections tend to be consistent in value and maintain a unified direction, processing module 9 can preliminarily determine that the pile foundation has an overall displacement trend.

[0067] To further verify the accuracy of this determination and avoid misjudgments caused by minor local deformations, processing module 9 derives the theoretical relative displacement between adjacent key sections based on the real-time absolute coordinate data of each key section through spatial geometric calculations. This theoretical value is the relative change between adjacent sections caused only by overall displacement, assuming the pile foundation is a rigid body without local bending deformation. Subsequently, this theoretical relative displacement is compared dimension by dimension with the real-time relative deformation data measured by the relative reference module 4. If the deviation between the two is not greater than the system's preset error threshold, it indicates that the measured relative deformation mainly originates from the overall rigid body movement of the pile foundation, rather than additional deformation caused by local bending. This formally confirms that the pile foundation only undergoes overall displacement and does not produce local bending deformation. At this point, since the absolute coordinate changes of all key sections are consistent, processing module 9 can directly select the absolute coordinate change of any one key section as the overall displacement of the pile foundation.

[0068] The above process enables accurate identification and quantification of overall displacement, effectively avoiding the risk of misjudgment that may be caused by a single data dimension. At the same time, it lays the foundation for subsequent elimination of overall displacement interference and focusing on local bending deformation analysis, further enhancing the processing module 9's ability to finely analyze the deformation state of the pile foundation. This ensures that the system maintains high accuracy in assessing the overall stability of the pile foundation and calculating key monitoring parameters in complex marine environments, providing more rigorous data support for verifying the accuracy of pile foundation installation during construction and for early warning of safety hazards during operation.

[0069] In some embodiments, the processing module 9 is further configured to determine that there is local bending deformation in the target pile segment between adjacent key sections when the absolute coordinate changes of adjacent key sections are not synchronized, calculate the difference in absolute coordinate changes of adjacent key sections based on the real-time absolute coordinate data of each key section, and use it as the theoretical local bending deformation; obtain the real-time relative deformation data of adjacent key sections measured by the relative reference module 4, and compare the theoretical local bending deformation with the real-time relative deformation data. When the theoretical local bending deformation is the same as the real-time relative deformation data, the local bending deformation or the real-time relative deformation data is determined as the actual local bending deformation of the target pile segment.

[0070] It is understandable that, in response to the non-uniform deformation of pile foundations in complex marine environments that may be caused by localized stress concentration, processing module 9 can determine whether local bending deformation exists based on the absolute coordinate changes of adjacent key sections. When the absolute coordinate changes of adjacent key sections are asynchronous, it indicates that the target pile segment between the two sections does not exhibit rigid body motion characteristics, but rather undergoes additional deformation due to bending. Based on this, it is directly determined that the target pile segment has local bending deformation. Subsequently, processing module 9 calculates the difference in absolute coordinate changes of adjacent key sections within the same monitoring period based on the real-time absolute coordinate data of each key section (after eliminating the synchronous influence of overall displacement, only the coordinate difference caused by local bending is retained). This difference is used as the theoretical local bending deformation, which quantifies the influence of local bending on the relative position of adjacent sections from a global coordinate perspective. Then, it calls the real-time relative deformation data measured by relative reference module 4 specifically for adjacent key sections. This data is a direct measured result of the local deformation between the two sections, truly reflecting the actual bending degree and deformation state of the target pile segment.

[0071] Subsequently, processing module 9 performs a precise dimension-by-dimensional comparison between the theoretical local bending deformation and the real-time relative deformation data. Since the theoretical value is derived from the global absolute coordinates, while the measured value is directly captured from the local relative deformation, if the two are completely consistent, it indicates that the theoretical derivation has not been affected by environmental interference or measurement errors, and the measured data is authentic and reliable, with no additional abnormal deformation factors involved. At this point, processing module 9 can directly determine the theoretical local bending deformation or the real-time relative deformation data as the actual local bending deformation of the target pile segment. This processing logic not only accurately locks the range of local bending deformation through the synchronous judgment of the absolute coordinate change, but also avoids the errors that may exist from a single data source by using the two-way verification of the "global derivation value" and the "local measured value," ensuring the accuracy of the calculation of the local bending deformation. At the same time, it realizes the precise quantification of the segmental deformation state of the pile body, providing core data support for identifying the stress concentration area of ​​the pile body and assessing the local structural safety. This further improves the analytical capability of processing module 9 for the complex deformation state of the pile foundation, enabling the entire monitoring system to accurately capture the overall displacement and meticulously identify local bending under complex sea conditions. Based on the above embodiments, an example diagram of the deformation results of wind turbine jacket foundation monitoring can be shown as follows. Figure 7 As shown.

[0072] In some embodiments, the distributed auxiliary channel in the monitoring system is built using spare optical fibers or dedicated sensing optical fibers in existing submarine cables of offshore wind power plants, simultaneously realizing distributed acoustic sensing and distributed temperature sensing functions: Distributed acoustic sensing technology transforms the optical fiber into a "distributed microphone," acquiring pile vibration signals in real time and analyzing pile modal frequencies. Changes in modal frequencies are used to infer the contact stiffness between the pile and the surrounding soil (decreased contact stiffness usually indicates soil loosening or erosion); simultaneously, distributed temperature sensing technology monitors the temperature field of the pile and the surrounding seabed with meter-level or even sub-meter-level spatial resolution. This not only provides a temperature compensation benchmark for other sensors but also, combined with abnormal temperature field distributions (such as sudden local temperature changes), helps determine the pile exposure area caused by seabed erosion. The synergy of these two data sources further improves the accuracy and reliability of identifying the pile foundation's mechanical state and erosion phenomena.

[0073] The formula for calculating the pile-soil contact stiffness corresponding to distributed acoustic sensing (DAS) is as follows:

[0074] Where ks represents the pile-soil equivalent contact stiffness (N / m³, to be determined); fn represents the nth modal frequency measured by DAS (Hz, only the first order is needed, β1≈1.875); m represents the mass per unit length of the pile (kg / m, known); L represents the pile length of the monitoring section (m, known); EI represents the pile bending stiffness (N·m², known); βn represents the modal eigenvalue (1.875 when n=1, a fixed constant). Based on this, when the current ks < 80% of the initial value (a threshold can be set), soil loosening / scouring is determined.

[0075] The scouring determination formula is as follows:

[0076] in, Tmeasured represents the temperature difference between the measured temperature and the seawater temperature (°C); Tmeasured represents the temperature of the pile body at a certain depth measured by DTS (°C); Tseawater represents the reference seawater temperature at the same time (°C, calculated from the temperature measured at the exposed section of the pile top). If the temperature is <0.5℃ (a threshold can be set) and continues for 24 hours, it can be determined that the pile body at that depth has been eroded and exposed.

[0077] The monitoring system can capture high-frequency vibration energy by attaching piezoelectric ceramics to the pile body, convert electromagnetic coils into kinetic energy by cutting magnetic field lines, and generate electricity by using a micro wave energy module driven by a float. With a wide-temperature battery pack, it can achieve an average power consumption of 3-5W and a range of ≥30 days under extreme sea conditions.

[0078] In the monitoring system, data preprocessing can be completed by a microcontroller unit / field programmable gate array. Multi-source data can be fused through extended Kalman filtering / unscented Kalman filtering algorithms. It supports event-triggered reporting, packet loss retransmission and breakpoint resumption. At the same time, it interacts with the shore station's "digital twin" model in real time to ensure data continuity and accurate analysis.

[0079] In some embodiments, the motion and deformation of the pile foundation can also be described by setting state equations and observation equations. The state equations typically include: the pile foundation's displacement (absolute coordinates), velocity (such as settlement rate, horizontal displacement rate), attitude angle (such as changes in tilt angle), and sensor drift errors (such as drift caused by temperature and pressure changes). The observation equations update the state variables based on the actual values ​​measured by the sensors (relative settlement, absolute coordinates, attitude data).

[0080] In the application, processing module 9 can use algorithms such as Extended Kalman Filter (EKF) or Unscented Kalman Filter (UKF) for data fusion. The iterative calculation process typically includes prediction and updating. Prediction: Based on the state and input data (such as external forces or environmental changes) from the previous moment, predict the position and attitude of the pile foundation; Updating: Compare the actual observations from the sensors with the predicted values ​​and adjust the state estimates. Through the iterative process, the estimated values ​​are continuously updated, ultimately yielding more accurate pile foundation settlement, tilt angle, and horizontal displacement.

[0081] Sensors (such as fiber Bragg gratings and inertial measurement units) are affected by environmental factors such as temperature and pressure, which can lead to measurement errors. By establishing drift error models (such as temperature drift and pressure drift), the system can automatically estimate and compensate for these errors, thereby improving measurement accuracy. For example, if temperature changes cause deviations in the strain signal output by the sensor, the data can be corrected using a preset temperature compensation model. Similarly, pressure changes can be corrected using a pressure compensation model.

[0082] After completing the above steps, the system will output the final settlement, tilt angle, and horizontal displacement data of the pile foundation. Specific accuracy is as follows: absolute settlement accuracy ≤ 1 mm; horizontal displacement accuracy ≤ 3 mm. Through the above data fusion and compensation process, the system can provide high-precision data in the deformation monitoring of offshore wind power pile foundations, thereby ensuring the safe operation of the infrastructure.

[0083] Suppose that at a certain moment, the system collects the following data: relative settlement data: ΔS = 0.3 mm (the settlement difference between two adjacent sensors measured by the differential pressure sensing unit 43); absolute coordinate data: the absolute coordinates of the pile top are (X1, Y1, Z1), and the absolute coordinates of the pile bottom are (X2, Y2, Z2); attitude data: the tilt angle is 0.02° (measured by the six-axis inertial measurement unit 22). Through the state equation and the observation equation, the system will use this observation data to calculate the overall displacement, local settlement, and attitude change of the pile foundation.

[0084] The processing module 9 can establish a deformation mechanism identification model based on the pre-built scour and plastic settlement identification algorithm, which integrates the data from the pore pressure gauge 33, the distributed acoustic wave sensing modal frequency and the acoustic Doppler current profiler (ADCP). The model mainly includes: scour exposure identification, plastic settlement identification and composite deformation identification.

[0085] Among them, the scour exposure identification is determined when the distributed acoustic wave sensor detects a short-term large drift in the modal frequency of the pile body (Δf>5%), and the pore pressure gauge 33 shows no significant cumulative change (dUw / dt<0.1kPa / h), while the acoustic Doppler current profiler detects that the near-bottom flow velocity exceeds the critical threshold (e.g., >1.5m / s), indicating that the pile body is exposed due to seabed scour. Plastic settlement is identified when pore pressure is slowly dissipated over a long period (dUw / dt < 0.05 kPa / h, duration > 7 days) as monitored by pore pressure gauge 33, and the settlement data shows a gradual increase (daily settlement rate > 0.05 mm / d), with no significant change in modal frequency (Δf < 2%). This is determined to be plastic settlement caused by soil consolidation. Composite deformation is identified when both of the above characteristics appear simultaneously (modal frequency drift and pore pressure dissipation). This is determined to be composite deformation caused by the coupling effect of scour and plastic settlement. Further analysis of the data from the reference pile 31 is needed to distinguish the primary and secondary influencing factors.

[0086] In the identification of composite deformation, when both modal frequency drift and pore pressure dissipation occur simultaneously, it is usually identified as a composite deformation resulting from the coupling effect of scour and plastic settlement. To more accurately identify and distinguish between scour and plastic settlement, further analysis using data from benchmark pile 31 is required.

[0087] Scouring, which loosens the soil surrounding the pile foundation, typically reduces the contact stiffness between the pile and the soil. When the contact stiffness decreases, the modal frequencies of the pile (especially lower-order modal frequencies) change significantly. Therefore, the decrease in pile-soil contact stiffness caused by scouring usually manifests as a large drift in modal frequencies, a change that is typically instantaneous and rapid. Plastic settlement, primarily caused by soil consolidation and settlement, is a process that is usually slow and has a relatively uniform impact on the pile foundation. Therefore, plastic settlement typically does not lead to drastic changes in modal frequencies, but rather exhibits a smaller and slower frequency drift. Scouring is usually accompanied by the loosening of the surrounding soil and the acceleration of water flow, resulting in sudden and drastic changes in pore pressure. Especially when scouring occurs in the soil layers near the pile foundation, it can lead to a rapid dissipation of pore pressure, which is usually a short-term change. Plastic settlement, on the other hand, is a long-term effect of the soil consolidation process, typically accompanied by a slow dissipation of pore pressure. This change in pore pressure is relatively stable and continuous.

[0088] To more accurately distinguish the primary and secondary influencing factors of scour and plastic settlement, the system can analyze the data from reference pile 31 in the following ways: Reference pile 31 data provides a reliable reference point, aiding in the analysis of pile foundation deformation. Reference pile 31 is typically located near the pile foundation, and its settlement changes can serve as an important basis for distinguishing between scour and plastic settlement: Settlement changes around reference pile 31 are usually more drastic and may be uneven. Due to soil loosening caused by scour, the settlement of reference pile 31 may exhibit large and irregular variations. Unlike scour, plastic settlement typically leads to a gradual increase in the settlement of reference pile 31. Due to soil consolidation, the settlement changes of reference pile 31 are more uniform and slower. Reference pile 31 data can also provide information on soil compaction status or strength.

[0089] For example, using data from the pore pressure gauge 33 and soil strength sensor, the system can determine whether the soil has experienced excessive scouring or settlement: if the soil around the reference pile 31 shows significant loosening or a decrease in strength, and the modal frequency changes drastically, it can be determined that scouring has a significant impact on pile foundation deformation. If the pore pressure of the soil decreases slowly, but the modal frequency changes are small and uniform, it can be determined that plastic settlement is dominant. Using technologies such as acoustic sensors and distributed temperature sensors, the water flow velocity and temperature field around the pile foundation can be monitored in real time to further distinguish between scouring and plastic settlement: scouring is typically characterized by high water flow velocity and abnormal local temperature changes, accompanied by an increase in the depth of pile foundation exposure. This information can be used to estimate the depth of scouring and determine its impact on pile foundation deformation. Scouring is usually accompanied by a gradual dissipation of pore pressure and a gradual increase in settlement rate, but it does not produce drastic local water flow changes.

[0090] Based on the above data, the system can distinguish the primary and secondary effects of scour and plastic settlement using the following steps: If the modal frequency changes drastically and is accompanied by a rapid dissipation of pore pressure, and the settlement of reference pile 31 is irregular, it can generally be identified as scour. If the modal frequency changes are small and the pore pressure dissipation is relatively gradual, and the settlement of reference pile 31 shows a stable increasing trend, it can be identified as plastic settlement. If both occur simultaneously, the system can further combine the settlement data of reference pile 31, soil strength changes, and water flow velocity parameters to comprehensively determine the relative influence of scour and plastic settlement. For example, if the water flow velocity caused by scour is high and causes local soil loosening, then scour is preferentially considered to have a greater impact on deformation; while if the settlement rate is slow and the modal frequency changes are small, it may be caused by plastic settlement.

[0091] The processing module 9 in the monitoring system can also be configured with a self-calibration and health diagnosis mechanism. This mechanism utilizes stable sea state conditions within small to medium wave windows (significant wave height Hs 0.5–1.5m) to automatically perform short-window self-calibration. The diagnosis mechanism includes data closure error calculation, threshold judgment, and hardware health diagnosis. Specifically, the data closure error calculation compares the relative settlement of the liquid level relative measurement system, the absolute settlement of the acoustic long baseline positioning system, and the settlement data of reference pile 31 to calculate the closure error (settlement - cumulative settlement - reference pile 31 settlement). The threshold judgment is that if the closure error is ≤10–15mm (or 3 times the measurement standard deviation 3σ), the system is considered normal; if the closure error exceeds the limit, a recalibration process is triggered to recalibrate sensor parameters (such as fiber optic sensor compensation coefficient and triaxial sensor zero bias). Hardware health diagnosis synchronously monitors status parameters such as sensor power supply voltage, communication signal strength, and sealed chamber pressure. If abnormal voltage (e.g., below 40V), signal interruption, or water ingress into the chamber (abnormal pressure) occurs, a hardware fault alarm is generated, prompting maintenance personnel to perform repairs.

[0092] The maintenance and installation of the aforementioned technical solution mainly includes two parts: system installation and maintenance. System installation consists of the installation of the multi-ring intelligent sensing hoop 2, the seabed local reference array 3, the liquid level relative measurement system, the acoustic long baseline positioning system, and the energy and communication module 8. The multi-ring intelligent sensing hoop 2 uses a segmented structural design, and docking and fixing are completed underwater using a remotely operated underwater vehicle (ROV). Before installation, the pile surface is cleaned to remove rust and marine organisms; during installation, the horizontal deviation of each ring is ensured to be ≤0.5°, and the spacing error between rings is ≤50mm; after installation, a sealing test is conducted (internal pressure test ≥1MPa, pressure held for 30 minutes with no leakage). The seabed local reference array 3 is installed using a piling vessel employing impact or vibratory pile driving technology to implant the reference pile 31 into the seabed at the designed depth (3–6m); after installation, 72 hours of static observation is conducted to verify the settlement stability of the reference pile 31 (settlement rate ≤0.1mm / d); the signal matching between the pile top reflection mark 34 and the sensing hoop and acoustic long baseline positioning system is adjusted.

[0093] The installation of the relative reference module 4 includes: prefabricating a sealed liquid level pipeline 41, made of corrosion-resistant stainless steel; ensuring a seal when connecting the pipeline to each sensor clamp (using a double O-ring sealing structure), and performing pre-filling and venting operations (the air bubble content in the pipeline after venting is ≤1%); and testing the response speed (≤1s) and measurement accuracy of the liquid level sensing unit after installation.

[0094] The absolute reference module 5 is installed by deploying the transponder at the designed location via a tugboat and securing it with anchoring device 52 (anchor chain length ≥ 2 times the water depth to prevent displacement). After installation, calibration is performed, using a calibration point with known coordinates (such as a nearby offshore platform) to correct the transponder's absolute coordinates, ensuring a ranging error ≤ 5mm. The energy and communication module 8 is installed by fixing the energy module 7 to the upper middle part of the pile (avoiding wave impact zones), and connecting the communication module 8 to a submarine cable or backup communication equipment via a waterproof connector. After installation, the stability of the energy output (voltage fluctuation ≤ ±2%) and the smoothness of the communication link (data transmission success rate ≥ 99%) are tested.

[0095] Remote diagnostics targets the real-time monitoring system status of the shore station operation and maintenance platform, including sensor data integrity, battery level, and communication quality. It uses data anomalies (such as missing data or excessive fluctuations) to predict potential faults. Regular maintenance involves annual on-site maintenance, including using an ROV to check the sensor clamp fixation, pipeline sealing, and the integrity of the reference pile 31; replacing aged antifouling coatings and sacrificial anodes (if applicable); and performing battery charge-discharge maintenance to ensure capacity ≥ 80% of rated capacity. Fault repair involves removing and replacing faulty modules via ROV if sensor malfunctions occur (e.g., no signal from the fiber Bragg grating); checking fiber optic links first if communication interruptions occur, and activating backup underwater acoustic / BeiDou communication if necessary; and re-deploying reference pile 31 and calibrating the system if settlement exceeds limits.

[0096] In some embodiments, this application also provides a method for monitoring offshore wind turbine foundation piles, which is executed based on an offshore wind turbine foundation pile monitoring system as described above. Figure 8 As shown, the offshore wind power pile foundation monitoring method includes the following steps S801 to S805.

[0097] S801: Receive measurement information from each of the multi-ring intelligent sensing hoops, the relative reference module, and the absolute reference module.

[0098] S802: Compensate the deformation and attitude information collected by each of the multi-ring intelligent sensing hoops according to the collected physical parameters to obtain deformation compensation information and attitude compensation information.

[0099] S803: Based on the deformation compensation information, the principal curvature of the pile body is obtained through differential calculation.

[0100] S804: Based on the principal curvature of the pile body, the curvature integral result is corrected using the attitude compensation information as the initial value, and the tilt angle and tilt direction of the offshore wind power pile foundation are obtained by inversion.

[0101] S805: Based on the real-time relative deformation data and the real-time absolute coordinate data, distinguish between the overall displacement and local bending deformation of the pile body, and determine the overall displacement and local bending deformation of each pile section of the offshore wind power pile foundation.

[0102] It should be noted that the offshore wind power pile foundation monitoring method provided in this application embodiment and the offshore wind power pile foundation monitoring system provided in this application embodiment are based on the same inventive concept. Therefore, the specific implementation of this embodiment can refer to the implementation of the aforementioned offshore wind power pile foundation monitoring system, and the repeated parts will not be described again.

[0103] In some embodiments, an electronic device provided in this application includes a processor and a memory; the memory stores a computer program, wherein the computer program, when executed by the processor, implements the above-described offshore wind power pile foundation monitoring method.

[0104] This application also provides a non-transitory computer storage medium storing a computer program thereon, which, when executed by a processor, implements the aforementioned method for monitoring offshore wind power pile foundations. This computer-readable medium may be included in the device / apparatus / system described in the above embodiments; or it may exist independently and not assembled into that device / apparatus / system. The aforementioned computer-readable medium carries one or more programs, which, when executed, implement the method as described in the embodiments of this application.

[0105] Those skilled in the art will understand that the features described in the various embodiments of this application can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this application. In particular, the features described in the various embodiments of this application can be combined and / or combined in various ways without departing from the spirit and teachings of this application. All such combinations and / or combinations fall within the scope of this application. Therefore, the scope of this application should not be limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A monitoring system for offshore wind turbine foundation piles, characterized in that, include: Multiple multi-ring intelligent sensing loops, relative reference modules, absolute reference modules, and processing modules; Multiple multi-ring intelligent sensing hoops are arranged vertically at intervals along the pile body of the offshore wind power pile foundation. The multi-ring intelligent sensing hoops are used to measure the strain information of the circumferential position of the pile body and the attitude information of the pile body in real time, and to collect multiple physical parameters in the marine environment. The relative reference module is used to measure the real-time relative deformation data between two adjacent key sections on the offshore wind turbine pile foundation; The absolute reference module is used to locate and measure the key sections of the offshore wind power pile foundation and obtain the real-time absolute coordinate data of each key section. The processing module is used to receive measurement information from each of the multi-ring intelligent sensing hoops, the relative reference module, and the absolute reference module, and to compensate for the deformation and attitude information collected by each of the multi-ring intelligent sensing hoops according to the collected physical parameters, so as to obtain deformation compensation information and attitude compensation information. Based on the deformation compensation information, the principal curvature of the pile body is obtained by differential calculation. Based on the principal curvature of the pile body, the curvature integral result is corrected using the attitude compensation information as the initial value, and the tilt angle and tilt direction of the offshore wind power pile foundation are obtained by inversion; and the overall displacement and local bending deformation of the pile body are distinguished according to the real-time relative deformation data and the real-time absolute coordinate data, and the overall displacement and local bending deformation of each pile body segment of the offshore wind power pile foundation are determined.

2. The offshore wind power pile foundation monitoring system as described in claim 1, characterized in that, The multi-ring intelligent sensing hoop includes multiple fiber Bragg grating strain rosettes, a six-axis inertial measurement unit, and an environmental parameter measurement unit. The multiple fiber Bragg grating strain rosettes are evenly distributed circumferentially. The fiber Bragg grating strain rosettes are used to measure strain information at their arrangement positions. The six-axis inertial measurement unit is used to measure the attitude information of the pile body in real time. The environmental parameter measurement unit is used to collect multiple physical parameters in the marine environment.

3. The offshore wind power pile foundation monitoring system as described in claim 2, characterized in that, The fiber Bragg grating strain flower is also equipped with a temperature compensation grating, which is used to eliminate the influence of temperature changes on the strain measurement results.

4. The offshore wind power pile foundation monitoring system as described in claim 1, characterized in that, The relative reference module includes a sealed liquid level pipeline, a differential pressure sensing unit, and a liquid level sensing unit. The sealed liquid level pipeline is used to connect adjacent multi-ring intelligent sensing clamps, and the sealed liquid level pipeline is filled with an inert working fluid. The differential pressure sensing unit is installed at the pipeline interface between adjacent multi-ring intelligent sensing clamps and is used to measure the pressure difference of the working fluid at both ends of the sealed liquid level pipeline in real time. The liquid level sensing unit is used to assist in monitoring the height change of the liquid column in the sealed liquid level pipeline.

5. The offshore wind power pile foundation monitoring system as described in claim 4, characterized in that, The sealed liquid level pipeline is also equipped with a temperature expansion compensation chamber, which is used to buffer the volume expansion of the inert working fluid caused by temperature changes.

6. The offshore wind power pile foundation monitoring system as described in claim 1, characterized in that, The absolute reference module includes a seabed local reference array and multiple acoustic long baseline transponders. The seabed local reference array includes multiple reference piles, which are arranged circumferentially along the offshore wind turbine foundation in a polygonal topological distribution. Each acoustic long baseline transponder is respectively installed on each of the reference piles.

7. The offshore wind power pile foundation monitoring system as described in claim 6, characterized in that, When the soil stiffness in the seabed area where the offshore wind turbine pile foundation is located is greater than a preset threshold, the local seabed reference array is set within a ring within a range of 1–2D from the pile foundation, where D is the diameter of the offshore wind turbine pile foundation. When the soil stiffness of the seabed area where the offshore wind turbine pile foundation is located is not greater than a preset threshold, the local seabed reference array is set within a ring within a range of 3–5D from the pile foundation.

8. The offshore wind power pile foundation monitoring system as described in claim 1, characterized in that, The processing module is also used to determine the absolute coordinate change of each key section based on the real-time absolute coordinate data of each key section; if the absolute coordinate change of all key sections is consistent, it is determined that the pile foundation has an overall displacement; the theoretical relative displacement between adjacent key sections is determined based on the real-time absolute coordinate data of each key section, and the theoretical relative displacement between adjacent key sections is compared with the real-time relative deformation data obtained by the relative reference module. If the comparison deviation value is not greater than the preset error threshold, it is confirmed that the pile foundation has an overall displacement and no local bending deformation has occurred. The overall displacement is the absolute coordinate change of any one key section.

9. The offshore wind power pile foundation monitoring system as described in claim 8, characterized in that, The processing module is further configured to determine that there is local bending deformation in the target pile segment between adjacent key sections when the absolute coordinate changes of adjacent key sections are not synchronized; calculate the difference in absolute coordinate changes of adjacent key sections based on the real-time absolute coordinate data of each key section, as the theoretical local bending deformation; obtain the real-time relative deformation data of adjacent key sections measured by the relative reference module; compare the theoretical local bending deformation with the real-time relative deformation data; and determine the local bending deformation or the real-time relative deformation data as the actual local bending deformation of the target pile segment when the theoretical local bending deformation is the same as the real-time relative deformation data.

10. A method for monitoring offshore wind turbine foundation piles, characterized in that, The offshore wind power pile foundation monitoring method is performed based on the offshore wind power pile foundation monitoring system as claimed in any one of claims 1 to 9; the offshore wind power pile foundation monitoring method includes: Receive measurement information from each of the multi-ring intelligent sensing loops, the relative reference module, and the absolute reference module; The deformation and attitude information collected by each multi-ring smart sensor hoop are compensated based on the collected physical parameters to obtain deformation compensation information and attitude compensation information. Based on the deformation compensation information, the principal curvature of the pile body is obtained through differential calculation; Based on the principal curvature of the pile body, the curvature integral result is corrected using the attitude compensation information as the initial value, and the tilt angle and tilt direction of the offshore wind power pile foundation are obtained by inversion. Based on the real-time relative deformation data and the real-time absolute coordinate data, the overall displacement of the pile body and the local bending deformation of each pile body segment are distinguished, and the overall displacement of the offshore wind power pile foundation and the local bending deformation of each pile body segment are determined.

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