Overwater pile foundation positioning method

Abstract

The invention provides an overwater pile foundation positioning method, and belongs to the technical field of overwater pile foundation construction.The overwater pile foundation positioning method comprises the steps that an overwater positioning datum point is established to form a first inclination vector system; a three-dimensional laser emitting device is installed, and the laser horizontal elevation angle is adjusted to 72 degrees to form a second inclination vector; calculating a water surface fluctuation influence index matrix; a square steel support system is built to form a three-dimensional positioning frame; measuring and calculating a stability index to evaluate the stability of the bracket; a main laser and auxiliary laser emitting device is installed to form a third inclination vector positioning system; constructing a fluctuation influence compensation function matrix; establishing a stable feedback index monitoring system to collect infinitesimal displacement data in real time; and constructing a pile position construction datum plane according to laser beam projection to guide the pile body to enter water for positioning. The technical problem that in the water pile foundation construction process, due to water surface fluctuation, the pile foundation positioning precision is low is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of water pile foundation construction, and in particular relates to a water pile foundation positioning method. Background Art

[0002] The construction of pile foundation on water is an important part of the construction of water conservancy projects, marine projects, cross-sea bridges, etc. The traditional methods of positioning pile foundation on water mainly rely on GPS positioning system, total station measurement and physical marking points. These methods can achieve high-precision positioning in a static environment. They usually measure the distance between the shore base reference point and the pile position, calculate the pile position coordinates based on the principle of triangulation, and then guide the pile body into position through a physical guidance device.

[0003] However, in actual construction environments, factors such as water surface fluctuations, water flow impacts, and wind impacts lead to poor stability of traditional positioning systems. GPS positioning signals are easily interfered with in aquatic environments, and accuracy is difficult to meet engineering requirements; total station measurements require a stable platform, and frequent vibrations in the aquatic environment lead to accumulated measurement errors; physical markers are easily displaced with water surface fluctuations, making it difficult to maintain accuracy. Especially in waters with large fluctuations such as oceans and rivers, the positioning deviation of pile foundations often reaches 10-20 cm.

[0004] Therefore, how to achieve high-precision positioning of pile foundations in a fluctuating water environment and establish a reliable dynamic compensation mechanism to eliminate the influence of water surface fluctuations on positioning accuracy has become a core technical problem that needs to be solved in the field of pile foundation construction on water. The existing technology lacks a systematic compensation method for the influence of water surface fluctuations and cannot effectively overcome the interference of dynamic changes in the water environment on the positioning accuracy of pile foundations. Summary of the invention

[0005] In view of this, the present invention provides a method for positioning a pile foundation on water, which can solve the technical problem in the prior art that the pile foundation positioning accuracy is low due to water surface fluctuations during the construction of the pile foundation on water.

[0006] The present invention is implemented as follows: The present invention provides a method for positioning underwater pile foundations, which includes: establishing underwater positioning reference points, setting three positioning reference points around the construction area to form a first inclined vector system, and using a total station to measure and determine the absolute coordinates of each reference point; installing a three-dimensional laser emission device on the positioning reference point, adjusting the laser horizontal elevation angle of the three-dimensional laser emission device to ensure that the laser beam forms a second inclined vector; calculating the water surface fluctuation influence index matrix; building a square steel support system; calculating the stability index; installing a main laser emission device and an auxiliary laser emission device to form a third inclined vector positioning system; constructing a fluctuation influence compensation function matrix, and dynamically adjusting the angles of the main laser emission device and the auxiliary laser emission device through a hydrodynamic fluctuation compensation equation; establishing a stability feedback index monitoring system; and guiding the pile body to enter the water for positioning by projecting the laser beams of the main laser emission device and the auxiliary laser emission device to construct a pile position construction reference plane.

[0007] Among them, the calculation of the water surface fluctuation influence index matrix includes: collecting the fluctuation data of the construction water area within 48 hours, establishing a sampling point matrix at 15-minute intervals, and calculating the fluctuation influence range.

[0008] Among them, the calculation of the stability index includes: dynamically measuring the displacement of the square steel support system under different water flow conditions, and establishing a mathematical model for the stability of the support.

[0009] Among them, the installation of the main laser emission device and the auxiliary laser emission device includes: installing the main laser emission device on the top of the vertical square steel, and installing two auxiliary laser emission devices on the parallel square steel respectively.

[0010] Among them, the establishment of the stability feedback index monitoring system includes: installing an attitude sensor on the square steel support system, collecting the minute displacement data of the square steel support system in real time, and adjusting the laser positioning accuracy.

[0011] Among them, the first inclined vector system refers to the spatial vector system formed by the three positioning reference points set around the underwater pile foundation construction area. The three positioning reference points are not on the same straight line. By measuring the spatial geometric relationship between the three positioning reference points and the target pile position, the spatial parameters required for accurate positioning are calculated.

[0012] Among them, the second inclined vector refers to the linear vector formed by the laser beam emitted from the positioning reference point in space, which is used to indicate the accurate position of the pile foundation in three-dimensional space and ensure the verticality and plane position accuracy of the pile foundation.

[0013] Among them, the third tilt vector positioning system refers to a three-dimensional space positioning network formed by the main laser emission device and the auxiliary laser emission device. The main laser emission device and the auxiliary laser emission device simultaneously emit lasers to form three space lines, and the intersection point thereof is the accurate position point of the pile foundation. The accurate positioning of the pile foundation is achieved by controlling the position of the intersection point of the three space lines.

[0014] Among them, the water surface fluctuation influence index matrix refers to a mathematical model that describes the influence degree of water surface fluctuation on the positioning system of the main laser emission device and the auxiliary laser emission device. The water surface fluctuation influence index matrix includes two dimensions: wave height factor and frequency factor. The water surface fluctuation influence index matrix is constructed by calculating the laser offset under different wave conditions and is used for the calculation of the fluctuation influence compensation function matrix.

[0015] Among them, the stability index refers to a quantitative parameter that evaluates the ability of the square steel support system to maintain stability under the action of water flow and waves. The stability index is calculated from the relationship between the displacements of each point of the square steel support system and the external force. The higher the value, the better the stability of the square steel support system, providing a reliable basis for the positioning systems of the main laser emission device and the auxiliary laser emission device.

[0016] Among them, the stability feedback index refers to a monitoring index that real-time monitors the small displacement changes of the square steel support system and quantifies them into numerical parameters. The stability feedback index is calculated by collecting data from a high-precision attitude sensor and is used to evaluate the current stable state of the square steel support system and guide the main laser emission device and the auxiliary laser emission device to make real-time adjustments.

[0017] Among them, the fluctuation influence compensation function matrix refers to a set of compensation algorithms established according to the water surface fluctuation influence index matrix. The fluctuation influence compensation function matrix provides corresponding compensation parameters for the laser offset under different fluctuation conditions, and adjusts the laser emission angles of the main laser emission device and the auxiliary laser emission device in real time through the motor drive system to eliminate the positioning error caused by water surface fluctuation.

[0018] Among them, the hydrodynamic fluctuation compensation equation includes a laser propagation refraction equation, a fluctuation prediction equation, a dynamic compensation equation, and a stability evaluation equation; the laser propagation refraction equation is used to calculate the change in the refraction angle of the laser beam at the air-water interface; the fluctuation prediction equation is used to predict the change in the water surface fluctuation state in the future short time; the dynamic compensation equation is used to calculate the angle parameters that the main laser emission device and the auxiliary laser emission device need to adjust; the stability evaluation equation is used to evaluate the stability of the system after compensation adjustment.

[0019] The construction of the pile position construction reference plane by the main laser emission device and the auxiliary laser emission device laser beam projection includes: measuring the intersection coordinates of the laser beam and the pile body, guiding the pile body to be positioned into the water, and ensuring that the pile foundation construction accuracy meets the requirements of meter-level accuracy control.

[0020] The present invention proposes a method for positioning a water-based pile foundation. By establishing a multi-level laser vector positioning system and a dynamic compensation mechanism, the problem of low pile foundation positioning accuracy in a water surface fluctuation environment is effectively solved. This method constructs a three-dimensional space positioning network, uses the first, second, and third tilt vector systems to form a three-dimensional positioning framework, and simultaneously establishes a water surface fluctuation influence index matrix and a fluctuation influence compensation function matrix to achieve precise compensation for the fluctuation environment.

[0021] Compared with the traditional technology, the present invention overcomes the interference of water surface fluctuations to the positioning system. Through a complete set of hydrodynamic fluctuation compensation equations, including the laser propagation refraction equation, the fluctuation prediction equation, the dynamic compensation equation, and the stability evaluation equation, a dynamic correlation model between the water surface fluctuation and the positioning system is established, and real-time compensation for the laser offset caused by the water surface fluctuation is achieved. At the same time, the stable feedback index monitoring system can collect the minute displacement data of the support system in real time, further ensuring the positioning accuracy.

[0022] Therefore, through the systematic vector positioning technology and the dynamic compensation mechanism, the present invention successfully solves the technical problem of low pile foundation positioning accuracy in a water surface fluctuation environment, enables the pile foundation construction accuracy to meet the requirements of meter-level accuracy control, and meets the needs of high-precision pile foundation construction for large water-based buildings such as water conservancy projects and ocean engineering. Brief Description of the Drawings

[0023] Figure 1 is a flow chart of the method of the present invention.

[0024] Figure 2 is a schematic diagram of the overall structure of the water-based pile foundation positioning system in Embodiment 2. Detailed Embodiments

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0026] As Figure 1 shown, is a flow chart of a method for positioning a water-based pile foundation provided by the present invention. This method includes the following steps:

[0027] S01. Establish a water-based positioning reference point, set three positioning reference points around the construction area to form a first tilt vector system, and use a total station to measure and determine the absolute coordinates of each reference point;

[0028] S02. Install the three-dimensional laser emission device at the positioning reference point, adjust the laser horizontal elevation angle of the three-dimensional laser emission device to 72°, ensure that the laser beam forms a second inclined vector, and achieve accurate pile position positioning;

[0029] S03. Calculate the water surface fluctuation influence index matrix, collect the fluctuation data of the construction water area within 48 hours, establish a sampling point matrix at 15-minute intervals, and calculate the fluctuation influence range;

[0030] S04. Build a square steel support system, with the vertical square steel 117 mm higher than the designed elevation of the pile top, and the two parallel square steels are 83 mm away from the edge of the pile respectively, forming a three-dimensional positioning framework;

[0031] S05. Measure and calculate the stability index, conduct dynamic displacement measurement on the square steel support system under different water flow conditions, and establish a mathematical model for the stability of the support;

[0032] S06. Install the main laser emission device on the top of the vertical square steel, and install two auxiliary laser emission devices on the parallel square steels respectively, forming a third inclined vector positioning system;

[0033] S07. Construct a fluctuation influence compensation function matrix, calculate the real-time compensation parameters according to the water surface fluctuation influence index matrix, and dynamically adjust the angles of the main laser emission device and the auxiliary laser emission devices through the hydrodynamic fluctuation compensation equation;

[0034] S08. Establish a stable feedback index monitoring system based on the mathematical model of the support stability, install attitude sensors on the square steel support system, collect the micro displacement data of the square steel support system in real time, and dynamically adjust the laser positioning accuracy according to the prediction results of the mathematical model of the support stability;

[0035] S09. Construct a pile position construction reference plane according to the projection of the laser beams of the main laser emission device and the auxiliary laser emission devices, measure the coordinates of the intersection points of the laser beams and the pile body, and guide the pile body to enter the water for positioning, ensuring that the pile foundation construction accuracy meets the requirements of centimeter-level accuracy control.

[0036] Among them, the first inclined vector system specifically refers to the space vector system formed by the three positioning reference points set around the water-based pile foundation construction area. The three positioning reference points are not on the same straight line. By measuring the spatial geometric relationship between the three positioning reference points and the target pile position, the spatial parameters required for accurate positioning are calculated.

[0037] Among them, the second inclined vector specifically refers to the straight line vector formed by the laser beam emitted from the positioning reference point in space, which is used to indicate the accurate position of the pile foundation in three-dimensional space and ensure the verticality and plane position accuracy of the pile foundation.

[0038] Among them, the third tilt vector positioning system specifically refers to a three-dimensional space positioning network formed by the main laser emission device and the auxiliary laser emission device. The main laser emission device and the auxiliary laser emission device simultaneously emit lasers to form three space lines, and the intersection point thereof is the precise position point of the pile foundation. The precise positioning of the pile foundation is achieved by controlling the position of the intersection point of the three space lines.

[0039] Among them, the water surface fluctuation influence index matrix specifically refers to a mathematical model that describes the influence degree of water surface fluctuation on the positioning system of the main laser emission device and the auxiliary laser emission device. The water surface fluctuation influence index matrix includes two dimensions: wave height factor and frequency factor. The water surface fluctuation influence index matrix is constructed by calculating the laser offset under different wave conditions and is used for the calculation of the fluctuation influence compensation function matrix.

[0040] Among them, the stability index specifically refers to a quantitative parameter for evaluating the ability of the square steel support system to maintain stability under the action of water flow and waves. The stability index is calculated from the relationship between the displacements of each point of the square steel support system and the external force. The higher the value, the better the stability of the square steel support system, providing a reliable basis for the positioning systems of the main laser emission device and the auxiliary laser emission device.

[0041] Among them, the stability feedback index specifically refers to a monitoring index that real-time monitors the minute displacement changes of the square steel support system and quantifies them into numerical parameters. The stability feedback index is calculated by collecting data through a high-precision attitude sensor and is used to evaluate the current stable state of the square steel support system and guide the main laser emission device and the auxiliary laser emission device to make real-time adjustments.

[0042] Among them, the fluctuation influence compensation function matrix specifically refers to a set of compensation algorithms established according to the water surface fluctuation influence index matrix. The fluctuation influence compensation function matrix provides corresponding compensation parameters for the laser offset under different fluctuation conditions, and adjusts the laser emission angles of the main laser emission device and the auxiliary laser emission device in real time through the motor drive system to eliminate the positioning error caused by water surface fluctuation.

[0043] The hydrodynamic wave compensation equation is used to calculate the influence of water surface fluctuations on the laser beam path and the required compensation amount. The inputs include wave height parameters, wave frequency parameters, wind speed factors, water depth parameters, and water temperature parameters, and the outputs are the laser offset compensation angle value and the displacement correction amount; the wave height parameters are derived from the wave height factor in the water surface fluctuation influence index matrix; the wave frequency parameters are derived from the frequency factor in the water surface fluctuation influence index matrix; the wind speed factor is obtained by real-time collection from an on-site weather station; the water depth parameter is obtained by underwater sonar measurement; the water temperature parameter is obtained by water temperature sensor measurement; the laser offset compensation angle value is used to adjust the emission angles of the main laser emission device and the auxiliary laser emission device; the displacement correction amount is used to correct the pile position construction reference plane coordinates.

[0044] The wave compensation equation set includes a laser propagation refraction equation, a wave prediction equation, a dynamic compensation equation, and a stability evaluation equation;

[0045] The laser propagation refraction equation is used to calculate the change in the refraction angle of the laser beam at the air-water interface. The inputs include the incident laser angle, water surface fluctuation height, air refractive index, water body refractive index, and atmospheric humidity parameter, and the outputs are the real-time refraction angle and the optical path offset amount; the incident laser angle is derived from the set angles of the main laser emission device and the auxiliary laser emission device; the water surface fluctuation height is derived from the wave height factor in the water surface fluctuation influence index matrix; the air refractive index is obtained by calculating meteorological parameters; the water body refractive index is obtained by water quality analysis; the atmospheric humidity parameter is obtained by a humidity sensor; the real-time refraction angle is used for calculation in the dynamic compensation equation; the optical path offset amount is used to calculate the pile position positioning error;

[0046] The wave prediction equation is used to predict the change in the water surface fluctuation state in the short term in the future. The inputs include historical fluctuation data, wind direction parameters, wind speed parameters, air pressure change rate, and surrounding terrain factors, and the output is the probability distribution of the fluctuation state within the prediction time period; the historical fluctuation data is derived from the water surface fluctuation influence index matrix; the wind direction parameter is obtained by a wind direction sensor; the wind speed parameter is obtained by a wind speed sensor; the air pressure change rate is obtained by continuous measurement and calculation by an air pressure sensor; the surrounding terrain factors are obtained by terrain measurement data; the probability distribution of the fluctuation state is used for calculation in the dynamic compensation equation;

[0047] The dynamic compensation equation is used to calculate the angle parameters that the main laser emission device and the auxiliary laser emission device need to adjust. The inputs include the current laser offset, the predicted fluctuation state, the target position coordinates, the compensation coefficient matrix, and the execution delay time. The output is the adjustment amount of the three-axis rotation angles of the main laser emission device and the auxiliary laser emission device. The current laser offset is derived from the optical path offset. The predicted fluctuation state is derived from the fluctuation state probability distribution. The target position coordinates are derived from the design drawings. The compensation coefficient matrix is derived from the fluctuation influence compensation function matrix. The execution delay time is obtained through system response testing. The adjustment amount of the three-axis rotation angles of the main laser emission device and the auxiliary laser emission device is used to control the motor rotation of the main laser emission device and the auxiliary laser emission device.

[0048] The stability evaluation equation is used to evaluate the system stability after compensation adjustment. The inputs include the positioning error before compensation, the positioning error after compensation, the system response time, the environmental disturbance intensity, and the cumulative error amount. The output is the system stability index and the reliability score. The positioning error before compensation is derived from the initial pile position measurement data. The positioning error after compensation is derived from the pile position measurement data after compensation adjustment. The system response time is obtained through the response testing of the main laser emission device and the auxiliary laser emission device. The environmental disturbance intensity is obtained through on-site environmental monitoring equipment. The cumulative error amount is obtained through continuous multiple measurements. The system stability index is used to evaluate the performance of the overall positioning system. The reliability score is used to determine whether it is necessary to readjust the main laser emission device and the auxiliary laser emission device.

[0049] The following details the specific implementation manners of the above steps.

[0050] The specific implementation of step S01 is to select three points with stable positions and wide fields of view around the construction water area as positioning reference points. These three positioning reference points are not on the same straight line and can form a stable triangular configuration. First, use an RTK-GNSS receiver for preliminary coordinate measurement to obtain the approximate coordinates of the reference points. Then, install a total station on the first reference point and use the resection method to determine the precise coordinates of the total station. The total station uses a Leica TS30 high-precision total station, with an angular measurement accuracy of 0.5 arcseconds and a distance measurement accuracy of 0.6 mm + 1 ppm. Conduct multiple repeated observations on the second and third reference points, with at least 4 measurement rounds for each reference point, and take the average value as the final coordinate value. The setup height of the total station needs to be accurately measured and recorded, with the error controlled within 0.5 mm. The reference point coordinates use the WGS84 coordinate system and are converted to the local construction coordinate system. The stability of the reference points needs to meet the requirement that the displacement within 24 hours is less than 5 mm. Establish a first tilt vector system through these reference points to provide a spatial reference framework for subsequent pile foundation positioning. The purpose of this step is to establish a high-precision spatial reference system to provide a basic coordinate framework for the entire pile foundation positioning process.

[0051] The specific implementation of step S02 is to install a three-dimensional laser emission device on each positioning reference point. A high-precision laser emitter is used, with a laser wavelength of 635 nm, a power of 5 mW, and a beam divergence angle of less than 0.5 mrad. This laser emission device has a three-axis electric adjustment function, with a horizontal adjustment accuracy of 0.01 degrees, a vertical adjustment accuracy of 0.01 degrees, and a rotation adjustment accuracy of 0.05 degrees. First, fix the laser emission device on the positioning reference point and use a high-precision level to adjust its level, with the horizontal error controlled within 10 arcseconds. Then, adjust the elevation angle of the laser emitter to 72 degrees. This angle is the optimal observation angle determined through calculation, which can minimize the influence of atmospheric refraction on the laser beam. After the laser beam is emitted, it forms a second tilt vector for determining the spatial position of the pile position. The laser emission device uses a two-axis gyroscope automatic compensation technology to ensure stability under micro-vibration conditions. The laser intensity can be automatically adjusted according to the ambient light conditions to ensure that the laser points can be clearly observed under different lighting conditions. The laser emission device also has a temperature compensation function and can work stably within the temperature range of -20°C to 50°C. The purpose of this step is to establish a high-precision laser guidance system to provide a visual spatial reference line for pile foundation positioning.

[0052] The specific implementation of step S03 is to deploy wave monitoring buoys in the construction water area and adopt gyro-stabilized platform technology to ensure that the buoys remain relatively stable under the action of waves. The buoys are equipped with high-precision three-dimensional acceleration sensors and tilt sensors. The sampling frequency is 100 Hz, the acceleration measurement range is ±10g, the accuracy is 0.005g, the tilt measurement range is ±30 degrees, and the accuracy is 0.01 degrees. Continuously collect water surface fluctuation data within 48 hours, including parameters such as wave height, wave period, wave direction, and waveform. Divide the 48-hour data into 192 time periods at 15-minute intervals, and collect 1000 data points within each time period to form a sampling point matrix of 192×1000. Use the fast Fourier transform algorithm to perform spectral analysis on the fluctuation data of each time period, and extract the main frequency components and corresponding amplitudes. Use the principal component analysis method for dimensionality reduction processing, and extract the first 3 principal components with the greatest influence as the fluctuation feature vectors. Based on these feature vectors, construct a water surface fluctuation influence index matrix, with the matrix dimension of 192×5, where the 5 dimensions correspond to the time period serial number, main wave height, main period, wave direction angle, and fluctuation intensity index respectively. The fluctuation intensity index is defined as the weighted combination of wave height and wave period, and the weight coefficients are determined through multiple experiments. The wave height weight is 0.7, and the wave period weight is 0.3. When the fluctuation intensity index exceeds 0.8, special wave compensation measures need to be taken. The purpose of this step is to provide a data basis for wave compensation for the subsequent laser positioning system through quantitative analysis of the water surface fluctuation law.

[0053] The specific implementation of step S04 is to determine the coordinates of the pile position center point according to the pile foundation design drawings and reasonably arrange a square steel support system around the pile position. Select square steel of Q345B material, with a specification of 100×100×8 mm, which has good stiffness and corrosion resistance. The square steel support system consists of one vertical square steel and two parallel square steels. The vertical square steel is fixed to the pre-set foundation by welding, and the welded joints need to be inspected by ultrasonic flaw detection to ensure that the welding quality meets the requirements of grade II welds. The vertical square steel is 117 mm higher than the designed elevation of the pile top, and this value is determined by calculating the intersection position of the pile top elevation and the best laser beam. The two parallel square steels are connected to the vertical square steel by high-strength bolts, and the connection is strengthened with stiffening plates to ensure structural stability. The parallel square steels are 83 mm away from the pile edge respectively, and this distance is determined by calculating to ensure the best intersection position of the laser beam and the pile body. The overall square steel support system adopts a three-point support structure and realizes precise positioning through fine-tuning bolts, with an adjustment accuracy of 0.1 mm. The outer surface of the support system is coated with reflective materials to enhance the visibility of the laser beam irradiation point. Anti-loosening measures are taken at all connection parts of the support system to ensure stability under the conditions of water flow impact and vibration. The purpose of this step is to establish a stable support system for the laser emission device and provide a solid spatial reference framework for accurately positioning the pile position.

[0054] The specific implementation of step S05 is to conduct dynamic displacement tests on the square steel support system under different water flow velocity conditions. First, high-precision displacement sensors are installed on the square steel support system. The accuracy of the sensors is 0.01 mm, and the sampling frequency is 50 Hz. At the same time, an acoustic Doppler current profiler is installed to measure the water flow velocity profile. The sampling depth is divided into 10 layers, and the thickness of each layer is 0.5 m. The displacement data of each point of the square steel support system are recorded under the conditions of water flow velocities of 0.5 m / s, 1.0 m / s, 1.5 m / s, and 2.0 m / s respectively. The test lasts for 30 minutes under each water flow condition. The least squares regression analysis method is used to establish a relationship model between the water flow velocity and displacement. The model form is a quadratic polynomial function. A numerical model of the square steel support system is established by finite element analysis software to simulate the stress state and deformation trend under different flow field conditions. Based on the displacement data and numerical simulation results, the stability index of the square steel support system is calculated. The stability index is defined as the ratio of the maximum allowable displacement of the support to the actual displacement, and the value range is from 1 to 10. The larger the value, the better the stability. When the water flow velocity is 1.5 m / s, the stability index should not be lower than 3.0. When the water flow velocity is 2.0 m / s, the stability index should not be lower than 2.0. The natural frequency of the support system is determined through modal analysis to avoid resonance with the water flow pulsation frequency. The purpose of this step is to evaluate the stability of the square steel support system under actual water flow conditions and ensure that the laser positioning system can work stably under various water flow conditions.

[0055] The specific implementation of step S06 is to select a high-precision laser emission device. The main laser emission device uses green laser with a wavelength of 532 nm and a power of 30 mW. The spot diameter is less than 5 mm at 100 m. The auxiliary laser emission device uses red laser with a wavelength of 650 nm and a power of 20 mW. The spot diameter is less than 8 mm at 100 m. The main laser emission device is installed on the top of the vertical square steel and fixed by a precision three-dimensional adjustment seat. The adjustment seat has a three-axis fine-tuning function, and the adjustment accuracy is 0.005 degrees. Two auxiliary laser emission devices are respectively installed on two parallel square steels and are also fixed by precision three-dimensional adjustment seats. Both the main laser emission device and the auxiliary laser emission devices are driven by servo motors to achieve remote precise adjustment. The power supplies of the three laser emission devices are powered by uninterruptible power supplies to ensure power supply stability. The laser emission device housing is designed with an IP67 protection level and can work normally in a humid environment. The laser emitter is equipped with a built-in temperature sensor and a temperature compensation system to ensure that the laser pointing stability is better than 5 arcseconds in the temperature range of -10°C to 45°C. The laser beams of the three laser emission devices intersect in space to form a third inclined vector positioning system. By adjusting the laser emission angles, the three laser beams intersect at the target pile position. The purpose of this step is to establish a multi-source laser positioning system and determine the precise spatial position of the pile position through the three-dimensional space positioning principle.

[0056] The specific implementation of step S07 is to construct a fluctuation influence compensation function matrix based on the water surface fluctuation influence index matrix obtained in step S03. First, the water surface fluctuation influence index matrix is decomposed into a wave height factor matrix and a frequency factor matrix, corresponding to the wave amplitude and frequency characteristics respectively. The multivariate nonlinear regression analysis method is used to establish the mapping relationship between the wave height factor, frequency factor and the laser beam offset. The compensation function matrix adopts a 5×5 grid structure, where the abscissa represents the wave height range and the ordinate represents the wave period range, and the matrix element value is the compensation parameter under the corresponding conditions. The wave height range is divided into 5 levels: 0 to 0.3 m, 0.3 to 0.6 m, 0.6 to 0.9 m, 0.9 to 1.2 m, and 1.2 to 1.5 m. The wave period range is divided into 5 levels: 1 to 2 s, 2 to 3 s, 3 to 4 s, 4 to 5 s, and 5 to 6 s. For each wave condition, the angle compensation amount that the laser needs to adjust is calculated through the hydrodynamic fluctuation compensation equation. The hydrodynamic fluctuation compensation equation is based on the simplified model of the Navier-Stokes equation, considering factors such as wave propagation, wind field influence, and water temperature gradient. The compensation algorithm adopts a prediction-correction model, predicting the wave state within the next 0.5 s based on the previous wave data and adjusting the laser emission angle in advance. The angle compensation amount adjusts the attitude of the laser emission device in real time through a servo motor, and the compensation frequency is not less than 10 Hz, and the motor response time is less than 50 ms. The purpose of this step is to establish a dynamic fluctuation compensation system to eliminate the influence of water surface fluctuation on the laser positioning system and improve the positioning accuracy.

[0057] The specific implementation of step S08 is to install an attitude sensor on the square steel support system, using a high-precision six-axis inertial measurement unit, which includes a three-axis accelerometer and a three-axis gyroscope. The accelerometer range is ±16g and the resolution is 0.002g; the gyroscope range is ±2000 degrees / second and the resolution is 0.07 degrees / second. The sensor sampling frequency is 200 Hz to ensure that high-frequency micro-vibrations can be captured. The sensor signal is processed by the Kalman filter algorithm to filter out random noise and extract the real displacement signal. The attitude data is transmitted to the control unit through the CAN bus, and the transmission delay is less than 5 ms. The control unit uses an ARM Cortex-M7 processor with an operating frequency of 400 MHz to process the attitude data in real time and calculate the displacement change. The stable feedback index is defined as the reciprocal of the displacement change rate per unit time, and the larger the value, the more stable the support. When the stable feedback index is lower than 30, the system issues a warning; when it is lower than 20, the positioning operation is paused and continues after the support is stable. The system also includes a temperature compensation module to eliminate the influence of temperature changes on the thermal expansion of the sensor and the support. Based on the change trend of the attitude data, the system can predict the change of the support stability in the next few seconds and take measures in advance to ensure the positioning accuracy. The purpose of this step is to establish a real-time monitoring system, dynamically evaluate the support stability, and provide stability guarantee for precise positioning.

[0058] The specific implementation of step S09 is to determine the reference plane for pile foundation construction according to the laser beam projection route formed by the main laser emission device and the auxiliary laser emission device. First, adjust the three laser emission devices so that the laser beams intersect at the theoretical pile position. Use a high-resolution CCD camera to capture the image of the laser point position, and the image resolution is not less than 5 million pixels. Extract the precise coordinates of the laser point through an image processing algorithm, and the algorithm uses Gaussian fitting technology with a positioning accuracy better than 0.2 mm. Measure the intersection coordinates of the laser beam and the pile surface to form a set of spatial positioning points. Calculate the pile body center axis equation according to the point set coordinates, and use the least squares method to fit the spatial straight line. During the process of the pile body entering the water, continuously monitor the change of the laser point position, and calculate the position and verticality of the pile body in real time. When the pile body deviates from the designed position by more than 5 mm, the system issues a deviation warning to guide the operator to make adjustments. The verticality error of the pile body should be controlled within 0.3%, that is, the horizontal deviation within every 100-meter height does not exceed 300 mm. The closed-loop control strategy is adopted during the water entry positioning process, and the position of the pile body is continuously corrected according to the real-time monitoring data. The final pile foundation construction accuracy target is that the plane position error is less than 10 mm and the verticality error is less than 0.2%. The purpose of this step is to achieve high-precision spatial positioning of the pile foundation and ensure that the pile foundation construction quality meets the design requirements.

[0059] The following details the mathematical models or calculation processes involved in the present invention.

[0060] The mathematical expression of the first tilt vector system is as follows:

[0061]

[0062] In the formula, (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3) are the spatial coordinates of three positioning reference points respectively; and are two base vectors formed by the reference points; is the cross product of the two base vectors to form a third base vector, and the three base vectors together constitute the first tilt vector system.

[0063] These three base vectors form the basis of the spatial rectangular coordinate system and are used to determine the spatial position of the target pile position. Establishing the coordinate system using the vector method has the advantages of simple calculation and clear geometric meaning. The coordinates are obtained through total station measurement, and the multiple measurement method is adopted during the measurement process to reduce random errors. The cross product operation ensures that the third base vector is perpendicular to the plane where the first two base vectors are located, forming a complete three-dimensional coordinate system.

[0064] The mathematical expression of the second tilt vector is as follows:

[0065]

[0066] In the formula, is the unit laser direction vector; α is the angle between the laser beam and the horizontal plane, with a value of 72°; β is the azimuth angle of the laser beam in the horizontal plane, which is determined according to the target pile position.

[0067] This vector represents the propagation direction of the laser beam in space, and the laser pointing is controlled by the angle parameters. The angle between the laser beam and the horizontal plane is set to 72° to balance the positioning accuracy and operation convenience. If the angle is too large, the horizontal accuracy will decrease; if the angle is too small, the influence of atmospheric refraction will increase. The azimuth angle is calculated and determined according to the position of the pile relative to the reference point.

[0068] The mathematical expression of the water surface fluctuation influence index matrix is as follows:

[0069]

[0070] In the formula, W is the water surface fluctuation influence index matrix; m is the number of time periods, with a value of 192; w i1 is the time period serial number; w i2 is the main wave height, in meters, with a range of 0.1 - 1.5; w i3 is the main period, in seconds, with a range of 1 - 6; w i4 is the wave direction angle, in degrees, with a range of 0 - 359; w i5 is the fluctuation intensity index, dimensionless, with a range of 0.1 - 1.0.

[0071] The calculation formula of the fluctuation intensity index is as follows:

[0072]

[0073] In the formula, h i is the wave height value of the current time period; h max is the maximum wave height value during the observation period; T i is the wave period of the current time period; T max is the maximum wave period during the observation period; 0.7 and 0.3 are the weight coefficients of the wave height and period respectively.

[0074] This index reflects the comprehensive intensity of the influence of waves on the laser positioning system. The weight configuration reflects the characteristic that the influence of wave height on positioning is greater than that of the period. The inverse relationship is adopted for the period term because the shorter the period, the higher the wave frequency and the greater the interference to the positioning system. The closer the index value is to 1, the more serious the fluctuation influence.

[0075] The calculation formula of the stability index is as follows:

[0076]

[0077] In the formula, S is the stability index, dimensionless, with a range of 1 - 10; D maxis the maximum allowable displacement of the support, in millimeters, with a value of 10; D act is the current actual displacement, in millimeters, ranging from 0.1 to 5; f n is the natural frequency of the support structure, in hertz, ranging from 5 to 20; f f is the main frequency of the water flow pulsation, in hertz, ranging from 0.5 to 3; λ is the time decay coefficient, with a value of 0.01; t is the continuous loading time, in seconds.

[0078] This index comprehensively considers the displacement response, frequency characteristics, and time stability of the support. The displacement ratio reflects the degree of displacement response of the support under the current water flow conditions; the frequency ratio reflects the ability of the system to avoid resonance, and having the natural frequency far from the water flow pulsation frequency is beneficial for stability; the exponential decay term reflects the influence of long-term continuous loading on the structural stability. Each parameter is obtained through on-site measurement, and the larger the final index value, the more stable the support.

[0079] The mathematical expression of the wave influence compensation function matrix is as follows:

[0080]

[0081] In the formula, C is the compensation function matrix; c ij is the compensation parameter vector under the condition of the i-th wave height and the j-th wave period. Each compensation parameter vector contains three components:

[0082] c ij =(Δθ x , Δθ y , Δθ z );

[0083] In the formula, Δθ x , Δθ y , Δθ z are the angles that the laser emission device needs to adjust on the three rotation axes, in degrees, ranging from -5 to 5.

[0084] The compensation parameter vector is calculated through the hydrodynamic wave compensation equation. This matrix provides the adjustment parameters of the laser emission device under different wave conditions to achieve dynamic compensation for the influence of water surface fluctuations. The matrix adopts a hierarchical structure, which is convenient for quickly finding the corresponding parameters and improving the system response speed.

[0085] The mathematical expression of the laser propagation refraction equation is as follows:

[0086]

[0087] Δd = h·tan(θ1 - θ2)·(1 + ε t );

[0088] Where, θ1 is the incident laser angle, in degrees, with a range of 60 to 80; θ2 is the refracted laser angle, in degrees; n1 is the refractive index of air, with a typical value of 1.0003; n2 is the refractive index of water, with a range of 1.33 to 1.35; Δθ w is the change in the incident angle caused by water surface fluctuations, in degrees, with a range of -5 to 5; A w is the fluctuation amplitude, in degrees, with a range of 0 to 10; f w is the fluctuation frequency, in Hertz, with a range of 0.1 to 1; t is time, in seconds; k h is the depth attenuation coefficient, with a value of 0.5; h is the water depth, in meters; Δd is the optical path offset, in meters; ε t is the temperature correction term, with a range of -0.02 to 0.02.

[0089] This equation describes the refraction phenomenon of a laser beam passing through the air-water interface based on Snell's law. Water surface fluctuations cause dynamic changes in the incident angle, which in turn affect the refraction angle and the optical path offset. The temperature correction term takes into account the influence of temperature changes on the refractive index. This equation is used to calculate the propagation path of the laser beam underwater in real time and provide optical path correction data for the positioning system.

[0090] The mathematical expression of the fluctuation prediction equation is as follows:

[0091]

[0092] Where, H p (t + Δt) is the wave height at the predicted time point, in meters; H(t - i·δt) is the historical wave height data, in meters; n is the number of historical data points, with a value of 10; a i is the autoregressive coefficient, obtained by least squares fitting; δt is the historical data time interval, in seconds, with a value of 15; b is the wind speed influence coefficient, with a value of 0.02; V w is the wind speed, in meters per second, with a range of 0 to 30; φ w is the wind direction angle, in degrees, with a range of 0 to 359; φ d is the main wave direction angle, in degrees, with a range of 0 to 359; c is the air pressure change rate influence coefficient, with a value of -0.05; is the air pressure change rate, in hectopascals per hour, with a range of -5 to 5; ε p is the prediction error, with a range of -0.2 to 0.2; P(H p ) is the probability density function of the predicted wave height; μ is the predicted wave height mean; σ is the predicted wave height standard deviation.

[0093] This equation uses an autoregressive moving average (ARMA) model combined with meteorological factors for short-term wave prediction. The autoregressive term utilizes the temporal correlation of wave evolution; the wind speed term considers the driving effect of wind on waves, and the angle between the wind direction and wave direction affects the effect; the rate of change of air pressure term reflects the impact of air pressure changes on waves. The prediction results are given in the form of a probability distribution, facilitating subsequent decision-making considering uncertainty.

[0094] The mathematical expression of the dynamic compensation equation is as follows:

[0095]

[0096] Where, is the angle vector that the laser emission device needs to adjust at the prediction time point, in degrees; τ is the system response delay time, in seconds, with a range of 0.05 - 0.2; M c is the compensation coefficient matrix, with a dimension of 3×3; H p (t + τ) is the wave height value at the prediction time point, in meters; H(t) is the current wave height value, in meters; is the unit vector of the target direction; K v is the velocity feedback gain coefficient, with a range of 0.1 - 1; is the angle change rate, in degrees / second; K a is the acceleration feedback gain coefficient, with a range of 0.01 - 0.1; is the angle change acceleration, in degrees / second² 2 .

[0097] This equation is based on the PID control principle and combines a predictive control strategy. The first term is the prediction compensation term, which adjusts the angle in advance according to the predicted wave height value; the second term is the velocity feedback term, which suppresses the overshoot of the angle change; the third term is the acceleration feedback term, which improves the dynamic response performance of the system. Through multi-variable coordinated control, precise angle adjustment of the laser emission device is achieved to compensate for the influence of water surface fluctuations.

[0098] The mathematical expression of the stability evaluation equation is as follows:

[0099]

[0100] Where, S i is the system stability index, dimensionless, with a range of 0 - 1; E b is the positioning error before compensation, in millimeters, with a range of 1 - 50; E a is the positioning error after compensation, in millimeters, with a range of 0.1 - 10; T r is the system response time, in seconds, with a range of 0.05 - 0.5; T max is the maximum allowable response time, in seconds, with a value of 1; D is the environmental disturbance intensity, dimensionless, with a range of 0.1 - 1; D maxis the maximum tolerable disturbance intensity, dimensionless, with a value of 1; A c is the cumulative error amount, in millimeters, ranging from 0 to 10; A max is the maximum allowable cumulative error, in millimeters, with a value of 10; α, β, γ, δ are weight coefficients, with values of 0.4, 0.2, 0.3, and 0.1 respectively; R s is the reliability score, dimensionless, ranging from 0 to 1; E thr is the error threshold, in millimeters, with a value of 5; D thr is the disturbance threshold, dimensionless, with a value of 0.8; λ is the time decay coefficient, with a value of 0.01; t is the operating time, in hours.

[0101] This equation evaluates the system stability from four aspects: error improvement, response speed, disturbance resistance performance, and error accumulation. The error improvement term reflects the compensation effect; the response speed term evaluates the real-time performance of the system; the disturbance resistance performance term characterizes the working ability of the system in an adverse environment; the error accumulation term considers the stability during long-term operation. The reliability score comprehensively considers the error level, disturbance intensity, and operating time, providing a decision-making basis for the automatic adjustment of the system. The weight configuration reflects the importance of error improvement and disturbance resistance performance in the evaluation, and the exponential decay represents the impact of long-term operation on the reliability.

[0102] The mathematical expression of the spatial straight line fitting equation is as follows:

[0103]

[0104] In the formula, is the parametric equation of the spatial straight line; is the position vector of a point on the straight line; is the direction vector of the straight line; E is the sum of squared errors; is the position vector of the i-th measurement point; is the distance from the point to the straight line; n is the number of measurement points.

[0105] Based on the least squares principle, this equation determines the spatial equation of the pile center axis by minimizing the sum of the squares of the distances from the measurement points to the fitted straight line. The distance from a point to a straight line is calculated using the cross product of vectors, which has the advantages of clear geometric meaning and simple calculation. The least squares method can effectively reduce the influence of random errors and improve the fitting accuracy. The straight line parameters are obtained by solving the system of partial derivative equations with respect to and .

[0106] The calculation formula for the pile verticality is as follows:

[0107]

[0108] In the formula, V is the pile verticality error, in percentage; is the axial direction vector of the pile body; is the unit vector (0, 0, 1) in the vertical direction.

[0109] This formula is based on the cosine theorem of the included angle of vectors and calculates the deviation between the axis of the pile body and the vertical direction. The ratio of the modulus of the vector cross product to the product of the moduli of the two vectors is equal to the sine value of the included angle, which is approximately equal to the angle value (in radians) when the angle is small. The result is multiplied by 100% to be converted into a percentage, which intuitively represents the perpendicularity error. This calculation method is simple and reliable and is applicable to engineering practice.

[0110] Optionally, the mathematical model of the support stability can be expressed as:

[0111]

[0112] In the formula, M is the mass matrix; C is the damping matrix; K is the stiffness matrix; is the displacement vector; is the external force vector, mainly the water flow force; t is the time variable.

[0113] The calculation formula of the mass matrix:

[0114]

[0115] In the formula, n e is the number of finite element cells; V e is the cell volume; ρ is the density of the square steel material, with a value of 7850 kg / m 3 ; N is the shape function matrix.

[0116] The calculation formula of the stiffness matrix:

[0117]

[0118] In the formula, B is the strain-displacement matrix; D is the elastic matrix. For linearly elastic materials, its expression is:

[0119]

[0120] In the formula, E is the elastic modulus of the square steel, with a value of 2.06×10 11 Pa; v is the Poisson's ratio, with a value of 0.3.

[0121] The damping matrix adopts the Rayleigh damping model:

[0122] C = αM + βK;

[0123] In the formula, α is the mass proportional damping coefficient, with a value range of 0.05 - 0.2; β is the stiffness proportional damping coefficient, with a value range of 0.001 - 0.005.

[0124] Water flow force calculation formula:

[0125]

[0126] In the formula, is the water flow force vector; C d is the drag coefficient, and the value for a square cross-section is 1.8 - 2.2; ρ w is the water density, with a value of 1000 kg / m 3 ; A is the flow-facing area; is the water flow velocity vector.

[0127] The support stability model is based on structural dynamics theory and is solved using the finite element method. The mass matrix characterizes the inertial characteristics of the structure; the stiffness matrix reflects the deformation resistance ability of the structure; the damping matrix describes the energy dissipation characteristics of the structure. The Rayleigh damping model can effectively simulate the damping characteristics of the support in water. The α term mainly affects the low-frequency response, and the β term mainly affects the high-frequency response. The water flow force adopts the simplified form of the Morrison equation, considering the non-linear relationship between the square of the flow velocity and the drag. The entire model is solved by numerical integration methods (such as the Newmark-β method) to obtain the dynamic response of the support under the action of water flow, providing basic data for the calculation of the stability index.

[0128] Specifically, the principle of the present invention is: The technical principle of the present invention is based on the idea of combining spatial vector positioning and dynamic compensation. Through a multi-level positioning system and compensation mechanism, high-precision positioning of the pile foundation under the water surface fluctuation environment is achieved.

[0129] First, the present invention establishes a three-layer spatial vector positioning system. The first tilt vector system is composed of three non-collinear positioning reference points to ensure the uniqueness of the geometric space; the second tilt vector is formed by a three-dimensional laser emission device at a 72° horizontal elevation angle to ensure the spatial accuracy of laser positioning; the third tilt vector positioning system is composed of a main laser emission device and an auxiliary laser emission device to form a three-dimensional spatial positioning network. These three layers of vector systems verify and complement each other, constituting a complete spatial positioning framework, fundamentally improving the geometric stability of the positioning system.

[0130] Secondly, the present invention innovatively establishes a water surface fluctuation influence index matrix and a fluctuation influence compensation function matrix, realizing the quantitative analysis and precise compensation of the influence of water surface fluctuations. By collecting the fluctuation data of the construction water area for 48 hours and establishing a sampling point matrix at 15-minute intervals, the influence range of fluctuations is accurately calculated. At the same time, based on the theory of hydrodynamics, a set of fluctuation compensation equations are constructed, including the laser propagation refraction equation, the fluctuation prediction equation, the dynamic compensation equation, and the stability evaluation equation, forming a complete dynamic compensation system. This compensation system can dynamically adjust the angle of the laser emission device according to the real-time monitored water surface fluctuation state, eliminating the positioning error caused by fluctuations.

[0131] Thirdly, the present invention designs a square steel support system and a stable feedback index monitoring system, further improving the stability of the positioning system. The vertical square steel is 117 mm higher than the designed elevation of the pile top, and the precise parameters of the two parallel square steels, each 83 mm away from the edge of the pile, form a three-dimensional positioning framework. The attitude sensor real-time collects the minute displacement data of the support system, evaluates the stability of the support through the stability index, and provides a reliable basis for the laser positioning system.

[0132] In summary, through the organic combination of the spatial vector positioning technology and the dynamic compensation mechanism, the present invention establishes a dynamic correlation model between the water surface fluctuation and the positioning system, realizing the high-precision positioning of the pile foundation under the water surface fluctuation environment, and having a reliable theoretical basis and technical logic.

[0133] The following provides a specific Embodiment 1 of the present invention, and the specific implementation manners of each step in this Embodiment 1 are described in detail as follows.

[0134] The specific implementation manner of step S01 is to select three points with stable positions and open views around the construction water area as positioning reference points. These three positioning reference points are not on the same straight line and can form a stable triangular configuration. First, use an RTK-GNSS receiver to perform preliminary coordinate measurement to obtain the approximate coordinates of the reference points. Then, install a total station on the first reference point and use the resection method to determine the precise coordinates of the total station. Conduct multiple repeated observations on the second and third reference points, with at least 4 sets of observations for each reference point, and take the average value as the final coordinate value. Through these reference points, a first tilt vector system is established, and its mathematical expression is as follows:

[0135]

[0136] In the formula, (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3) are the spatial coordinates of the three positioning reference points respectively; and are two base vectors formed by the reference points; The cross product of two basis vectors forms a third basis vector, and the three basis vectors together constitute the first inclined vector system. Establishing a coordinate system using vector methods has the advantages of simple calculation and clear geometric meaning. The purpose of this step is to establish a high-precision spatial reference system to provide a basic coordinate framework for the entire pile foundation positioning process. The setup height of the total station needs to be accurately measured and recorded, with the error controlled within 0.5 millimeters. The coordinates of the reference points use the WGS84 coordinate system and are converted to the local construction coordinate system. The stability of the reference points needs to meet the requirement that the displacement within 24 hours is less than 5 millimeters.

[0137] The specific implementation of step S02 is to install a three-dimensional laser emission device on each positioning reference point. A high-precision laser emitter is used, with a laser wavelength of 635 nanometers, a power of 5 milliwatts, and a beam divergence angle less than 0.5 milliradians. This laser emission device has a three-axis electric adjustment function, with a horizontal adjustment accuracy of 0.01 degrees, a vertical adjustment accuracy of 0.01 degrees, and a rotational adjustment accuracy of 0.05 degrees. First, fix the laser emission device on the positioning reference point and use a high-precision level to adjust its level, with the horizontal error controlled within 10 arcseconds. Then, adjust the elevation angle of the laser emitter to 72 degrees. This angle is the optimal observation angle determined through calculation, which can minimize the influence of atmospheric refraction on the laser beam. After the laser beam is emitted, it forms a second inclined vector, and its mathematical expression is as follows:

[0138]

[0139] In the formula, is the unit laser direction vector; α is the angle between the laser beam and the horizontal plane, with a value of 72°; β is the azimuth angle of the laser beam in the horizontal plane, which is determined according to the target pile position. This vector represents the propagation direction of the laser beam in space, and the laser pointing is controlled through the angle parameters. The angle between the laser beam and the horizontal plane is set to 72° to balance the positioning accuracy and operation convenience. An overly large angle will lead to a decrease in horizontal accuracy, while an overly small angle will increase the influence of atmospheric refraction. The purpose of this step is to establish a high-precision laser guidance system to provide a visual spatial reference line for pile foundation positioning.

[0140] The specific implementation of step S03 is to deploy wave monitoring buoys in the construction water area. The gyro-stabilized platform technology is adopted to ensure the relative stability of the buoys under the action of waves. The buoys are equipped with high-precision three-dimensional acceleration sensors and inclination sensors. The sampling frequency is 100 Hz. The acceleration measurement range is ±10g, and the accuracy is 0.005g. The inclination measurement range is ±30 degrees, and the accuracy is 0.01 degrees. Continuously collect water surface fluctuation data within 48 hours, including parameters such as wave height, wave period, wave direction, and waveform. Divide the 48-hour data into 192 time periods at 15-minute intervals. 1000 data points are collected within each time period, forming a sampling point matrix of 192×1000. Use the fast Fourier transform algorithm to perform spectral analysis on the fluctuation data of each time period, and extract the main frequency components and corresponding amplitudes. Use the principal component analysis method for dimensionality reduction processing, and extract the first 3 principal components with the greatest influence as the fluctuation feature vectors. Based on these feature vectors, construct the water surface fluctuation influence index matrix, and its mathematical expression is as follows:

[0141]

[0142] In the formula, W is the water surface fluctuation influence index matrix; m is the number of time periods, with a value of 192; w i1 is the time period serial number; w i2 is the main wave height, in meters, with a range of 0.1 to 1.5; w i3 is the main period, in seconds, with a range of 1 to 6; w i4 is the wave direction angle, in degrees, with a range of 0 to 359; w i5 is the fluctuation intensity index, dimensionless, with a range of 0.1 to 1.0. The calculation formula for the fluctuation intensity index is as follows:

[0143]

[0144] In the formula, h i is the wave height value of the current time period; h max is the maximum wave height value during the observation period; T i is the wave period of the current time period; T max is the maximum wave period during the observation period; 0.7 and 0.3 are the weight coefficients of the wave height and period respectively. The purpose of this step is to provide a data basis for wave compensation for the subsequent laser positioning system through quantitative analysis of the water surface fluctuation law. When the fluctuation intensity index exceeds 0.8, special wave compensation measures need to be taken.

[0145] The specific implementation of step S04 is to determine the coordinates of the pile position center point according to the pile foundation design drawing and reasonably arrange the square steel support system around the pile position. Square steel of Q345B material with a specification of 100×100×8 mm is selected, which has good rigidity and corrosion resistance. The square steel support system consists of one vertical square steel and two parallel square steels. The vertical square steel is fixed to the pre-set foundation by welding, and the welded joints need to be inspected by ultrasonic flaw detection to ensure that the welding quality meets the requirements of Class II welds. The vertical square steel is 117 mm higher than the designed elevation of the pile top, and this value is determined by calculating the intersection position of the pile top elevation and the best laser beam position. The two parallel square steels are connected to the vertical square steel by high-strength bolts, and stiffening plates are used at the connection to ensure the structural stability. The parallel square steels are 83 mm away from the edge of the pile respectively, and this distance is determined by calculating to ensure the best intersection position of the laser beam and the pile body. The overall square steel support system adopts a three-point support structure and is precisely positioned through fine-tuning bolts with an adjustment accuracy of 0.1 mm. The purpose of this step is to establish a stable support system for the laser emission device and provide a stable spatial reference framework for accurately positioning the pile position.

[0146] The specific implementation of step S05 is to conduct dynamic displacement tests on the square steel support system under different water flow velocity conditions. First, high-precision displacement sensors with an accuracy of 0.01 mm and a sampling frequency of 50 Hz are installed on the square steel support system. At the same time, an acoustic Doppler current profiler is installed to measure the water flow velocity profile, and the sampling depth is divided into 10 layers with a thickness of 0.5 m for each layer. The displacement data of each point of the square steel support system are recorded under the conditions of water flow velocities of 0.5 m / s, 1.0 m / s, 1.5 m / s, and 2.0 m / s, and the test lasts for 30 minutes under each water flow condition. The least squares regression analysis method is used to establish a relationship model between the water flow velocity and displacement, and the model form is a quadratic polynomial function. A numerical model of the square steel support system is established through finite element analysis software, and the mathematical model of the support stability can be expressed as:

[0147]

[0148] In the formula, M is the mass matrix; C is the damping matrix; K is the stiffness matrix; is the displacement vector; is the external force vector, mainly the water flow force; t is the time variable. The calculation formula for the mass matrix:

[0149]

[0150] In the formula, n e is the number of finite element units; V e is the unit volume; ρ is the density of the square steel material, with a value of 7850 kg / m 3 ; N is the shape function matrix. The calculation formula for the stiffness matrix:

[0151]

[0152] In the formula, B is the strain-displacement matrix; D is the elastic matrix. The damping matrix adopts the Rayleigh damping model:

[0153] C = αM + βK;

[0154] In the formula, α is the mass proportional damping coefficient, with a value range of 0.05 - 0.2; β is the stiffness proportional damping coefficient, with a value range of 0.001 - 0.005. The calculation formula for the water flow force:

[0155]

[0156] In the formula, is the water flow force vector; C d is the drag coefficient, with a value of 1.8 - 2.2 for a square cross-section; ρ w is the water density, with a value of 1000 kg / m 3 ; A is the flow-facing area; is the water flow velocity vector. Based on the displacement data and the numerical simulation results, calculate the stability index of the square steel support system, and its calculation formula is as follows:

[0157]

[0158] In the formula, S is the stability index, dimensionless, with a range of 1 - 10; D max is the maximum allowable displacement of the support, in millimeters, with a value of 10; D act is the current actual displacement, in millimeters, with a range of 0.1 - 5; f n is the natural frequency of the support structure, in hertz, with a range of 5 - 20; f f is the main frequency of the water flow pulsation, in hertz, with a range of 0.5 - 3; λ is the time decay coefficient, with a value of 0.01; t is the continuous loading time, in seconds. The purpose of this step is to evaluate the stability of the square steel support system under actual water flow conditions and ensure that the laser positioning system can work stably under various water flow conditions. When the water flow velocity is 1.5 m / s, the stability index should not be lower than 3.0; when the water flow velocity is 2.0 m / s, the stability index should not be lower than 2.0.

[0159] The specific implementation method of step S06 is to select a high-precision laser emitting device. The main laser emitting device uses a green laser with a wavelength of 532 nanometers, a power of 30 milliwatts, and a spot diameter of less than 5 millimeters at 100 meters. The auxiliary laser emitting device uses a red laser with a wavelength of 650 nanometers, a power of 20 milliwatts, and a spot diameter of less than 8 millimeters at 100 meters. The main laser emitting device is installed on the top of the vertical square steel and fixed by a precise three-dimensional adjustment seat. The adjustment seat has a three-axis fine-tuning function with an adjustment accuracy of 0.005 degrees. The two auxiliary laser emitting devices are respectively installed on two parallel square steels and are also fixed by a precise three-dimensional adjustment seat. Both the main laser emitting device and the auxiliary laser emitting device are driven by servo motors, which can achieve remote precision adjustment. The laser beams of the three laser emitting devices intersect in space to form a third tilt vector positioning system. By adjusting the laser emission angle, the three laser beams intersect at the target pile position. The purpose of this step is to establish a multi-source laser positioning system to determine the precise spatial position of the pile position through the principle of three-dimensional space positioning. The laser transmitter housing adopts IP67 protection grade design and can work normally in humid environment. The laser transmitter has built-in temperature sensor and temperature compensation system to ensure that the laser pointing stability is better than 5 arc seconds in the temperature range of -10℃ to 45℃.

[0160] The specific implementation method of step S07 is to construct a fluctuation influence compensation function matrix based on the water surface fluctuation influence index matrix obtained in step S03. First, the water surface fluctuation influence index matrix is decomposed into a wave height factor matrix and a frequency factor matrix, which correspond to the wave amplitude and frequency characteristics respectively. The mapping relationship between the wave height factor, the frequency factor and the laser beam offset is established by using the multivariate nonlinear regression analysis method. The mathematical expression of the compensation function matrix is as follows:

[0161]

[0162] Where C is the compensation function matrix; c ij is the compensation parameter vector under the conditions of the i-th level wave height and the j-th level wave period. Each compensation parameter vector contains three components:

[0163] c ij =(Δθ x , Δθ y , Δθ z );

[0164] In the formula, Δθ x , Δθ y , Δθ zThey are the angles that the laser emission device needs to adjust on three rotation axes, in degrees, with a range of -5 to 5. For each wave condition, the angle compensation amount that the laser needs to adjust is calculated through the hydrodynamic wave compensation equation. The hydrodynamic wave compensation equation includes the laser propagation refraction equation, the wave prediction equation, the dynamic compensation equation, and the stability evaluation equation. The mathematical expression of the laser propagation refraction equation is as follows:

[0165]

[0166] Δd = h·tan(θ1 - θ2)·(1 + ε t );

[0167] In the formula, θ1 is the incident laser angle, in degrees, with a range of 60 to 80; θ2 is the refracted laser angle, in degrees; n1 is the air refractive index, with a typical value of 1.0003; n2 is the water body refractive index, with a range of 1.33 to 1.35; Δθ w is the change in the incident angle caused by the water surface fluctuation, in degrees, with a range of -5 to 5; A w is the wave amplitude, in degrees, with a range of 0 to 10; f w is the wave frequency, in hertz, with a range of 0.1 to 1; t is the time, in seconds; k h is the depth attenuation coefficient, with a value of 0.5; h is the water depth, in meters; Δd is the optical path offset, in meters; ε t is the temperature correction term, with a range of -0.02 to 0.02. The mathematical expression of the wave prediction equation is as follows:

[0168]

[0169] In the formula, H p (t + Δt) is the wave height at the predicted time point, in meters; H(t - i·δt) is the historical wave height data, in meters; n is the number of historical data points, with a value of 10; a i is the autoregressive coefficient, obtained by least squares fitting; δt is the historical data time interval, in seconds, with a value of 15; b is the wind speed influence coefficient, with a value of 0.02; V w is the wind speed, in meters per second, with a range of 0 to 30; φ w is the wind direction angle, in degrees, with a range of 0 to 359; φ d is the main wave direction angle, in degrees, with a range of 0 to 359; c is the air pressure change rate influence coefficient, with a value of -0.05; is the air pressure change rate, in hectopascals per hour, with a range of -5 to 5; ε p is the prediction error, with a range of -0.2 to 0.2; P(H p ) is the probability density function of the predicted wave height; μ is the predicted wave height mean; σ is the predicted wave height standard deviation. The mathematical expression of the dynamic compensation equation is as follows:

[0170]

[0171] In the formula, is the angle vector that the laser emission device needs to adjust at the predicted time point, with the unit of degree; τ is the system response delay time, with the unit of second, and the range is 0.05 - 0.2; M c is the compensation coefficient matrix, with the dimension of 3×3; H p (t + τ) is the wave height value at the predicted time point, with the unit of meter; H(t) is the current wave height value, with the unit of meter; is the unit vector of the target direction; K v is the velocity feedback gain coefficient, and the range is 0.1 - 1; is the angle change rate, with the unit of degree / second; K a is the acceleration feedback gain coefficient, and the range is 0.01 - 0.1; is the angle change acceleration, with the unit of degree / second² 2 . The purpose of this step is to establish a dynamic fluctuation compensation system, eliminate the influence of water surface fluctuations on the laser positioning system, and improve the positioning accuracy. The compensation algorithm adopts a prediction-correction model, predicts the wave state within the next 0.5 seconds based on the previous wave data, and adjusts the laser emission angle in advance. The angle compensation amount adjusts the attitude of the laser emission device in real time through a servo motor, the compensation frequency is not less than 10 Hz, and the motor response time is less than 50 ms.

[0172] The specific implementation method of step S08 is to install an attitude sensor on the square steel support system, using a high-precision six-axis inertial measurement unit, which includes a three-axis accelerometer and a three-axis gyroscope. The measurement range of the accelerometer is ±16g, and the resolution is 0.002g; the measurement range of the gyroscope is ±2000 degree / second, and the resolution is 0.07 degree / second. The sampling frequency of the sensor is 200 Hz to ensure that high-frequency micro-vibrations can be captured. The sensor signal is processed by the Kalman filter algorithm to filter out random noise and extract the true displacement signal. The attitude data is transmitted to the control unit through the CAN bus, and the transmission delay is less than 5 ms. The control unit uses an ARM Cortex-M7 processor with an operating frequency of 400 MHz to process the attitude data in real time and calculate the displacement change. The stability feedback index is defined as the reciprocal of the displacement change rate per unit time, and the larger the value, the more stable the support. When the stability feedback index is lower than 30, the system issues a warning; when it is lower than 20, the positioning operation is paused and continued after the support is stable. The system also includes a temperature compensation module to eliminate the influence of temperature changes on the thermal expansion of the sensor and the support. Based on the change trend of the attitude data, the system can predict the change of the support stability within the next few seconds and take measures in advance to ensure the positioning accuracy. The mathematical expression of the stability evaluation equation is as follows:

[0173]

[0174] In the formula, S i is the system stability index, dimensionless, ranging from 0 to 1; E b is the positioning error before compensation, in millimeters, ranging from 1 to 50; E a is the positioning error after compensation, in millimeters, ranging from 0.1 to 10; T r is the system response time, in seconds, ranging from 0.05 to 0.5; T max is the maximum allowable response time, in seconds, with a value of 1; D is the environmental disturbance intensity, dimensionless, ranging from 0.1 to 1; D max is the maximum tolerable disturbance intensity, dimensionless, with a value of 1; A c is the cumulative error amount, in millimeters, ranging from 0 to 10; A max is the maximum allowable cumulative error, in millimeters, with a value of 10; α, β, γ, δ are weight coefficients, with values of 0.4, 0.2, 0.3, and 0.1 respectively; R s is the reliability score, dimensionless, ranging from 0 to 1; E thr is the error threshold, in millimeters, with a value of 5; D thr is the disturbance threshold, dimensionless, with a value of 0.8; λ is the time decay coefficient, with a value of 0.01; t is the running time, in hours. The purpose of this step is to establish a real-time monitoring system to dynamically evaluate the stability of the support and provide stability guarantee for precise positioning.

[0175] The specific implementation method of step S09 is to determine the pile foundation construction reference plane according to the laser beam projection route formed by the main laser emission device and the auxiliary laser emission device. First, adjust the three laser emission devices so that the laser beams intersect at the theoretical pile position. Use a high-resolution CCD camera to capture the laser point position image, and the image resolution is not less than 5 million pixels. Extract the precise coordinates of the laser points through an image processing algorithm, and the algorithm uses Gaussian fitting technology with a positioning accuracy better than 0.2 millimeters. Measure the intersection coordinates of the laser beam and the pile surface to form a set of spatial positioning points. Calculate the pile body central axis equation according to the point set coordinates, and use the least squares method to fit the spatial straight line. Its mathematical expression is as follows:

[0176]

[0177]

[0178] In the formula, is the parametric equation of the spatial straight line; is the position vector of a point on the straight line; is the straight line direction vector; E is the sum of squared errors; is the position vector of the i-th measurement point; is the distance from the point to the straight line; n is the number of measurement points. The pile body verticality calculation formula is as follows:

[0179]

[0180] Wherein, V is the verticality error of the pile body, with the unit of percentage; is the vector in the axial direction of the pile body; is the unit vector (0, 0, 1) in the vertical direction. During the process of the pile body entering the water, continuously monitor the change of the laser point position, and calculate the position and verticality of the pile body in real time. When the pile body deviates from the designed position by more than 5 mm, the system issues a deviation warning to guide the operator to make adjustments. The verticality error of the pile body should be controlled within 0.3%, that is, the horizontal deviation within every 100 m height does not exceed 300 mm. The closed-loop control strategy is adopted during the water entry positioning process, and the position of the pile body is continuously corrected according to the real-time monitoring data. The final pile foundation construction accuracy target is that the plane position error is less than 10 mm and the verticality error is less than 0.2%. The purpose of this step is to achieve the high-precision spatial positioning of the pile foundation and ensure that the pile foundation construction quality meets the design requirements.

[0181] In addition, in a further specific implementation manner of this embodiment, step S08 also considers combining the mathematical model of the bracket stability with the real-time monitoring system to establish a feedforward-feedback composite control system based on model prediction, dynamically evaluate the bracket stability and predict the change trend, so as to provide a more reliable stability guarantee for precise positioning. Specifically, the specific implementation manner of step S08 is to install attitude sensors on the square steel bracket system, and adopt a high-precision six-axis inertial measurement unit, including a three-axis accelerometer and a three-axis gyroscope. The measuring range of the accelerometer is ±16g, and the resolution is 0.002g; the measuring range of the gyroscope is ±2000 degrees / second, and the resolution is 0.07 degrees / second. The sampling frequency of the sensor is 200 Hz to ensure that high-frequency micro-vibrations can be captured. The sensor signals are processed by the Kalman filter algorithm to filter out random noise and extract the real displacement signals. The attitude data is transmitted to the control unit through the CAN bus, and the transmission delay is less than 5 ms. The control unit uses an ARM Cortex-M7 processor with an operating frequency of 400 MHz to process the attitude data in real time and calculate the displacement change. Input the collected real-time data into the mathematical model of the bracket stability established in step S05, that is: Predict the possible displacement changes of the bracket in the short term in the future by solving this equation. Calculate the stable feedback index based on the prediction results. This index is defined as the weighted product of the reciprocal of the displacement change rate per unit time and the prediction accuracy of the bracket stability mathematical model. The larger the value, the more stable the bracket. When the stable feedback index is lower than 30, the system issues a warning; when it is lower than 20, the positioning operation is paused and continues after the bracket is stable. The system also includes a temperature compensation module to eliminate the influence of temperature changes on the thermal expansion of sensors and brackets. Based on the prediction results of the bracket stability mathematical model, the system can predict the change trend of bracket stability 3 to 5 seconds in advance and take measures in advance to ensure the positioning accuracy. The mathematical expression of the stability evaluation equation is as follows:

[0182]

[0183] In the formula, the newly added P a is the prediction accuracy of the bracket stability mathematical model, dimensionless, with a range of 0 to 1; P max is the maximum value of the prediction accuracy, dimensionless, with a value of 1; η is the prediction accuracy weight coefficient, with a value of 0.2; μ is the prediction influence coefficient in the reliability score, with a value of 0.15.

[0184] To better understand and implement the present invention, the following provides Example 2 of a specific application scenario of the present invention: In the construction of an offshore wind farm project in a certain sea area, the water-based pile foundation positioning method of the present invention is used to perform high-precision positioning and installation of a wind power pile foundation with a diameter of 6 meters. The water depth in this sea area is about 20 meters, the annual wave height is between 0.5 and 1.8 meters, and the maximum water flow velocity can reach 2.5 m / s, with extremely high requirements for the pile foundation positioning accuracy.

[0185] First, select three relatively fixed and well-visible positions in the construction area to establish positioning reference points, which are located in the northeast, northwest, and southwest directions of the planned pile foundation installation, about 150 meters away from the pile position. The three points form an irregular triangle. Use an RTK-GNSS receiver combined with a Leica TS30 high-precision total station to determine the coordinates of the reference points through the multi-observation method (6 observations per point). The specific measurement results are as Figure 2 shown. Figure 2 gives the overall structural schematic diagram of the water-based pile foundation positioning system. The system mainly consists of three major parts: the positioning reference point system, the square steel bracket system, and the laser positioning system. The positioning reference point system consists of three non-collinear fixed reference points, which are respectively installed around the construction water area. The precise coordinate positions of these three reference points are clearly marked in the figure. They are connected by dotted lines to form the first inclined vector system, constituting a three-dimensional spatial reference network. Each reference point is supported by a strong bracket, and a waterproof fixing device is provided at the bottom of the bracket to ensure stability in the water surface environment. A reflection mark is installed on the top of the reference point for precise measurement by the total station, and the absolute coordinate data is stored in the system database. The square steel bracket system is located Figure 2Center: A vertical square steel is 117 mm higher than the designed elevation of the pile top, with a cross-section of 16 mm × 16 mm. Two parallel square steels are fixed at a 90° angle to the vertical square steel, each 83 mm away from the pile edge. A weighted base is provided at the bottom of the square steel support to improve the overall stability. In the figure, the laser positioning system consists of three laser emission devices: The main laser emission device is installed on the top of the vertical square steel and is designed with a precision adjustment mechanism that can perform fine angle adjustment with an accuracy of 0.01°. Two auxiliary laser emission devices are respectively installed on the tops of the two parallel square steels, and all three devices are designed with waterproof and moisture-proof features. In the figure, the laser beam projection paths are marked with different colored lines to form a third inclined vector positioning system. The intersection point of the three laser lines is the precise positioning point of the pile body, and the relative position relationship between this point and the pile body is shown in the figure. The system is also equipped with multiple sensor devices: The attitude sensor installed on the square steel support monitors the minute displacement changes of the support in real time with an accuracy of 0.1 mm; The water surface fluctuation monitor collects water area fluctuation data and constructs a water surface fluctuation influence index matrix; The meteorological parameter collection device collects environmental data such as wind speed, wind direction, and air pressure to provide inputs for fluctuation prediction. The data transmission lines and the layout positions of the signal processing unit are marked in the figure. The electric control part of the system is located in a waterproof box and includes a main controller, a data processing unit, a communication module, etc., and is connected to the construction command center through a wireless network. The motor drive system of the laser emission device automatically adjusts the laser emission angle according to the calculation results of the fluctuation influence compensation function matrix to eliminate the influence of water surface fluctuations.

[0186] The measurement results are shown in Table 1:

[0187] Table 1 Measurement Results of the Coordinates of the Positioning Reference Points

[0188] Reference Point Number X Coordinate (m) Y Coordinate (m) Z Coordinate (m) Standard Deviation (mm) BP01 2537.462 4628.135 3.782 2.3 BP02 2295.874 4592.451 3.924 2.1 BP03 2318.657 4358.278 3.865 2.5

[0189] According to the coordinates of the reference points, calculate the first inclined vector system:

[0190] Install laser emission devices at the three reference points, adjust the elevation angle to 72°, and make the three laser beams intersect at the target pile position by adjusting the horizontal azimuth angle. The parameter settings of the laser devices are shown in Table 2:

[0191] Table 2 Parameter Settings of the Laser Emission Devices

[0192] Reference Point Number Laser Wavelength (nm) Power (mW) Elevation Angle (°) Azimuth Angle (°) BP01 635 5 72.00 238.74 BP02 635 5 72.00 143.26 BP03 635 5 72.00 37.82

[0193] 48 hours before construction, deploy wave monitoring buoys in the construction water area to collect water surface fluctuation data. Through fast Fourier transform and principal component analysis, extract the water surface fluctuation characteristics and establish a water surface fluctuation influence index matrix. Some results are shown in Table 3:

[0194] Table 3 Water Surface Fluctuation Influence Index Matrix (Partial Data)

[0195] Time Period Serial Number Main Wave Height (m) Main Period (s) Wave Direction Angle (°) Wave Intensity Index 1 0.72 3.5 135 0.52 2 0.85 3.2 132 0.61 3 1.03 2.8 128 0.73 4 0.94 3.1 130 0.67 5 0.78 3.6 138 0.55

[0196] Build a square steel support system around the target pile position. The vertical square steel is 117 mm higher than the designed elevation of the pile top, and the distance between the two parallel square steels from the pile edge is 83 mm each. Use square steel of Q345B material with a specification of 100×100×8 mm. Conduct static and dynamic tests on the support system and establish a mathematical model for the stability of the support. Among them, the mass matrix, stiffness matrix, and damping matrix are obtained according to finite element analysis. The main parameters are: mass proportional damping coefficient α = 0.12; stiffness proportional damping coefficient β = 0.0025; resistance coefficient C d = 1.95.

[0197] Test the stability of the support under different water flow conditions and calculate the stability index. The results are shown in Table 4:

[0198] Table 4 Test results of the support stability index under different water flow conditions

[0199]

[0200] Install a main laser emission device (green laser, wavelength 532 nm, power 30 mW) on the top of the vertical square steel, and install auxiliary laser emission devices (red laser, wavelength 650 nm, power 20 mW) on the two parallel square steels respectively to form a third inclined vector positioning system.

[0201] Based on the water surface fluctuation influence index matrix, construct a 5×5 fluctuation influence compensation function matrix, and calculate the laser angle compensation amount through the hydrodynamic fluctuation compensation equation. The refractive index parameters are set as: air refractive index n1 = 1.0003, seawater refractive index n2 = 1.344. The historical data parameters used in the fluctuation prediction equation are set as: number of historical data points n = 10, historical data time interval δt = 15 s, wind speed influence coefficient b = 0.02, air pressure change rate influence coefficient c = -0.05.

[0202] Install a six-axis inertial measurement unit on the square steel support system. The sensor accuracy parameters are shown in Table 5:

[0203] Table 5 Attitude sensor accuracy parameters

[0204] Sensor Type Measurement Range Resolution Sampling Frequency (Hz) Triaxial Accelerometer ±16g 0.002g 200 Triaxial Gyroscope ±2000° / s 0.07° / s 200

[0205] Use the Kalman filter algorithm to process the sensor data. The weight coefficients of the stability evaluation equation are set as: α = 0.4, β = 0.2, γ = 0.3, δ = 0.1. The stability feedback index threshold is set as: warning threshold 30, pause threshold 20.

[0206] During the pile positioning process, a high-resolution CCD camera (8 million pixels) is used to capture the position of the laser points, and the precise coordinates of the laser points are extracted through Gaussian fitting technology. According to the intersection coordinates of the laser beam and the pile, the least squares method is used to fit the space line to determine the central axis of the pile. During the actual construction process, the pile positioning accuracy reached 8.2 mm, and the perpendicularity error was 0.17%.

[0207] Compared with the traditional on-water pile foundation positioning method, the present invention has significant technological progress. The traditional method mainly relies on GPS, underwater sonar or manual measurement by divers for pile foundation positioning. The measurement accuracy can usually only reach the centimeter level (10 - 30 cm), and the accuracy further decreases under bad sea conditions; the perpendicularity control usually relies on empirical judgment, and the accuracy is difficult to guarantee. In addition, the traditional method lacks an effective compensation mechanism for the influence of water surface fluctuations and water flow, resulting in the positioning accuracy being greatly affected by environmental factors. While the present invention realizes the positioning accuracy of millimeter level (<10 mm) and the perpendicularity control within 0.2% by establishing a multi-inclination vector system, a mathematical model of bracket stability and a compensation function matrix for the influence of fluctuations. Especially the application of the mathematical model of bracket stability enables the system to adapt to different water flow conditions and still maintain stable operation when the water flow speed reaches 2.5 m / s, greatly expanding the construction operation time window. The introduction of the compensation function matrix for the influence of fluctuations enables the system to predict and dynamically compensate for the influence of water surface fluctuations on laser positioning, ensuring precise positioning can still be carried out under the sea condition with a wave height of 1.5 m. These technological innovations significantly improve the installation efficiency of offshore wind power pile foundations, reduce construction risks, and provide reliable technical support for the construction of offshore wind farms.

[0208] It should be noted that the detailed explanations of the variables involved in the present invention are shown in Tables 6 and 7 below.

[0209] Table 6 Explanation Table of Variables (Part 1)

[0210]

[0211] Table 7 Explanation Table of Variables (Part 2)

[0212]

[0213]

[0214] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention.

Claims

1. A method for positioning a pile foundation in water, characterized in that, Including: Establishing a waterborne positioning reference point, setting three positioning reference points around the construction area to form a first inclined vector system, and using a total station to measure and determine the absolute coordinates of each reference point; installing a three-dimensional laser emitting device on the positioning reference point, adjusting the laser horizontal elevation angle of the three-dimensional laser emitting device to ensure that the laser beam forms a second inclined vector; calculating a water surface fluctuation influence index matrix; building a square steel support system; calculating a stability index; installing a main laser emitting device and an auxiliary laser emitting device to form a third inclined vector positioning system; constructing a fluctuation influence compensation function matrix, and dynamically adjusting the angles of the main laser emitting device and the auxiliary laser emitting device through a hydrodynamic fluctuation compensation equation; Establishing a stable feedback index monitoring system; constructing a pile position construction reference plane according to the laser beams projected by the main laser emitting device and the auxiliary laser emitting device, and guiding the pile body to be positioned into the water.

2. The water-based pile foundation positioning method according to claim 1, wherein The calculating of the water surface fluctuation influence index matrix includes: collecting the fluctuation data of the construction water area within 48 hours, establishing a sampling point matrix at 15-minute intervals, and calculating the fluctuation influence range.

3. The method for positioning an underwater pile foundation according to claim 2, wherein The calculating of the stability index includes: dynamically measuring the displacement of the square steel support system under different water flow conditions, and establishing a mathematical model for the stability of the support.

4. The method for positioning the underwater pile foundation according to claim 3, wherein, The installing of the main laser emitting device and the auxiliary laser emitting device includes: installing the main laser emitting device on the top of the vertical square steel, and installing two auxiliary laser emitting devices on the parallel square steels respectively.

5. The method for positioning a water-based pile foundation according to claim 4, wherein The establishing of the stable feedback index monitoring system includes: installing attitude sensors on the square steel support system, collecting the minute displacement data of the square steel support system in real time, and adjusting the laser positioning accuracy.

6. The method for positioning a water-based pile foundation according to claim 5, wherein, The first inclined vector system refers to the space vector system formed by the three positioning reference points set around the waterborne pile foundation construction area. The three positioning reference points are not on the same straight line. By measuring the spatial geometric relationship between the three positioning reference points and the position of the target pile, the spatial parameters required for accurate positioning are calculated.

7. The method for positioning the underwater pile foundation according to claim 6, wherein The second inclined vector refers to the straight line vector formed by the laser beam emitted from the positioning reference point in space, which is used to indicate the accurate position of the pile foundation in three-dimensional space, and ensure the verticality and plane position accuracy of the pile foundation.

8. The method for positioning a water-based pile foundation according to claim 7, wherein The third inclined vector positioning system refers to the three-dimensional space positioning network formed by the main laser emitting device and the auxiliary laser emitting device. The main laser emitting device and the auxiliary laser emitting device simultaneously emit lasers to form three space straight lines, and the intersection point thereof is the accurate position point of the pile foundation. The accurate positioning of the pile foundation is achieved by controlling the position of the intersection point of the three space straight lines.

9. The method for positioning a water-based pile foundation according to claim 8, wherein The water surface fluctuation influence index matrix refers to the mathematical model describing the influence degree of the water surface fluctuation on the positioning system of the main laser emitting device and the auxiliary laser emitting device. The water surface fluctuation influence index matrix includes two dimensions: wave height factor and frequency factor. The water surface fluctuation influence index matrix is constructed by calculating the laser offset under different wave conditions, and is used for the calculation of the fluctuation influence compensation function matrix.

10. The method for positioning a water-based pile foundation according to claim 9, characterized in that, The stability index refers to a quantitative parameter for evaluating the ability of the square steel support system to maintain stability under the action of water flow and waves. The stability index is calculated from the relationship between the displacements of each point of the square steel support system and the external force. The higher the value, the better the stability of the square steel support system, providing a reliable basis for the positioning system of the main laser emission device and the auxiliary laser emission device.

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