High-precision leveling construction method for deepwater foundation trench gravel pier

Abstract

The invention discloses a deepwater foundation trench gravel pier high-precision leveling construction method, and belongs to the technical field of ocean engineering construction. The method solves the problems that the efficiency is low, the precision is poor, the risk is high, the state of the throwing and filling body cannot be evaluated in real time and the dynamic underwater environment is difficult to deal with due to the fact that the deep water foundation trench depends on diver operation. According to the technical scheme, a construction ship is accurately positioned and parked; a leveling frame with an inertial navigation and sonar altimeter is put down, and remote hydraulic leveling is carried out; a telescopic riprapping funnel integrated with a camera and a flow velocity sensor is put down for riprapping, and the length of a guide pipe and riprapping point positions are automatically adjusted based on elevation, flatness, flow velocity and tide level data collected in real time; the high-frequency vibration slicking mechanism is automatically controlled to slick stones; and finally scanning and accepting. The method is mainly used for high-precision leveling construction of large-area gravel foundations (such as immersed tube tunnel foundations and gravity type wharf foundation beds) in the deepwater environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of offshore engineering construction. More particularly, the present application relates to a high-precision leveling construction method for deep-water foundation trench rockfill piers, which is particularly suitable for high-precision leveling construction of large-area rockfill foundations such as immersed tube tunnel foundations and gravity wharf beds. BACKGROUND

[0002] In the field of deep-water foundation trench rockfill pier construction, the traditional leveling method has long relied on underwater operations by divers. Divers need to dive into deep water environments and use their naked eyes and underwater measuring tools to judge and measure the surface conditions of the rockfill body. This method has several obvious limitations. First, manual underwater measurement is low in efficiency, and the measurement results are significantly affected by the individual experience of the diver, underwater visibility, and physical condition, resulting in strong subjectivity and poor repeatability of the measurement data, making it difficult to ensure accuracy. Second, surface command personnel cannot directly perceive the real-time state of underwater rockfill, and can only rely on verbal descriptions or intermittent communication from divers to make decisions. This experience-based remote operation lacks objective data support and makes it difficult to achieve real-time optimization and adjustment of construction parameters.

[0003] The traditional method lacks real-time and quantitative evaluation means for the shape of the underwater rockfill body. During construction, it is not possible to continuously obtain elevation and flatness data of the rockfill surface, and only after the completion of a single pier construction can a workboat be used to carry a multi-beam sounding system for post-scan detection. If the detection finds that the flatness does not meet the standard, remedial measures need to be taken, which not only significantly increases the construction cost, but also causes delays in the construction period. This post-detection mode makes the construction process uncontrollable and makes it difficult to achieve true process quality control.

[0004] Another outstanding problem is that the traditional construction method is difficult to effectively respond to the influence of the deep-water dynamic environment. The underwater flow velocity, direction, and tidal level change constantly, which will have a significant impact on the falling trajectory and accumulation shape of the rockfill. However, the throwing rate of the stone is traditionally set as a fixed value based on experience, and cannot be dynamically adjusted according to the change in water flow velocity, resulting in the rockfill being easily dispersed under strong water flow or being piled up too high in weak water flow environment, causing poor uniformity and uneven density of the rockfill body, directly affecting the overall stability and long-term durability of the rockfill pier.

[0005] Therefore, there has been a long-felt need in the art for a leveling construction method for large-area deep-water foundation trench rockfill piers that can overcome the above limitations to achieve high-precision construction control of the shape of the underwater rockfill body. SUMMARY

[0006] It is an object of the present application to solve at least the above problems and to provide at least the advantages described later.

[0007] In order to achieve the purposes and other advantages according to the present application, a deep water foundation groove caisson high-precision leveling construction method is provided, comprising: S1, the construction ship is moved to the design axis position of the construction pier based on the RTK-GPS positioning signal and is anchored and positioned; S2, the leveling frame carrying the inertial navigation unit and the sonar height measuring instrument is lowered to above the foundation groove construction pier position on the seabed, the distance between the leveling frame and the foundation groove bottom surface is monitored in real time by the sonar height measuring instrument during the lowering, after being lowered to the foundation bed surface, the three-dimensional attitude data fed back by the inertial navigation unit and the height data fed back by the sonar height measuring instrument are used to remotely and hydraulically synchronously control the multiple supporting legs of the leveling frame through the control console, so that the top surface reaches the design elevation and is kept horizontal; S3, the telescopic riprap hopper is lowered, the guide pipe of the hopper is integrated with an underwater camera and a flow rate sensor, the distance between the hopper outlet and the foundation bed surface is adjusted to 1.0-2.0m, and the riprap is thrown into the leveling frame through the hopper; during the riprapping, the riprap diffusion and accumulation image is captured by the underwater camera and is processed to obtain the riprapping surface elevation and flatness data; the flow rate sensor monitors the flow rate of the hopper outlet; the tide level sensor monitors the tide level; the integrated control system receives the riprapping surface elevation, flatness, flow rate and tide level data, automatically adjusts the guide pipe length based on the tide level and the real-time riprapping surface elevation, so that the vertical distance between the hopper outlet and the riprapping surface is maintained at 1.0-2.0m, and the riprapping point position is adjusted based on the flatness data to supplement the riprapping material to the low-lying area; S4, after the stone covers the top surface of the leveling frame, the high-frequency vibration scraping mechanism integrated in the leveling frame is started to scrape off the stone exceeding the top surface; the start and stop and operation of the high-frequency vibration scraping mechanism are automatically controlled by the integrated control system, and the steps include: the integrated control system receives the real-time flatness data processed by the underwater camera, and when the average elevation of the riprapping surface reaches the design elevation of the top surface of the leveling frame and the real-time flatness data change rate is lower than the preset threshold, a start instruction is automatically sent; the high-frequency vibration scraping mechanism reciprocally scrapes at a fixed speed along the preset track, and the operation is automatically stopped when the integrated control system monitors that the deviation of the top surface flatness of the pier body is not more than the preset difference threshold.

[0008] Preferably, it further comprises: S5, after the riprapping and leveling of a single riprap pier are completed, the leveling frame and the telescopic riprap hopper are lifted; S6, the working boat carrying the multi-beam sounding system is used to scan, detect and accept the constructed riprap pier; S7, steps S1-S6 are repeated to construct the next construction pier position until the construction of all construction pier positions is completed.

[0009] Preferably, before the leveling frame lowering step, the multi-beam sounding system carried by the working boat is used to fully cover the seabed groove for scanning and measuring, and the seabed groove excavation surface elevation is reviewed.

[0010] Preferably, the size of the rock fragments used in the rock throwing step is 10-50 mm, and the gradation is continuous.

[0011] Preferably, in step S3, the integrated control system dynamically adjusts the conveying rate of the stone based on the real-time flow rate data at the outlet of the funnel monitored by the flow rate sensor. Specifically, the integrated control system has a pre-stored correspondence table of flow rate and conveying rate, which specifies the conveying rate values of the stone corresponding to different flow rate intervals; the integrated control system queries the correspondence table and automatically adjusts the stone conveying rate to the corresponding target value according to the interval in which the real-time flow rate falls.

[0012] Preferably, the integrated control system is also provided with a data recording and remote transmission module, which is used to record the sensor data, control instructions and equipment state information throughout the construction process, and to transmit the sensor data, control instructions and equipment state information to the shore-based monitoring center in real time through a satellite communication link.

[0013] Preferably, in step S2, the bottom of each leg of the leveling frame is provided with a pressure sensor. After the top surface of the leveling frame is adjusted to the design elevation and kept level, the integrated control system continuously monitors the pressure data at the bottom of each leg. If the pressure value of a single leg decreases by more than a first pre-set threshold value, while the pressure values of one or more other legs increase by more than a second pre-set threshold value, and the horizontal inclination data of the leveling frame fed back by the inertial navigation unit exceeds a third pre-set threshold value, the integrated control system determines that the foundation under the leg has been destabilized or eroded, and the integrated control system issues an alarm and automatically suspends the subsequent rock throwing operation.

[0014] Preferably, in step S3, the specific steps of real-time acquisition of the elevation and flatness data of the filling surface include continuously capturing underwater video streams during the rock throwing process at a pre-set frame rate threshold through the underwater high-definition camera integrated on the telescopic rock throwing funnel duct, and transmitting the video streams to the integrated control system in real time through armored optical cables. The integrated control system sequentially performs the following processing on the received image sequences: Each frame of image is processed to enhance the image contrast and edge features, including histogram equalization and scattering effect elimination based on physical model; Based on binocular vision or structured light three-dimensional reconstruction algorithm, the same feature points in the left and right images are matched, and the three-dimensional point cloud data set representing the current filling surface morphology is calculated through triangulation method; The three-dimensional point cloud data is registered with the design coordinate system of the leveling frame, and a continuous digital elevation model is generated through gridding processing and interpolation algorithm; Based on the digital elevation model, the average elevation of the entire filling area and the flatness data representing the degree of surface undulation are calculated in real time.

[0015] The present application at least includes the following beneficial effects: First, the present application effectively overcomes the problem that traditional deep water leveling operation relies on manual work and precision is difficult to guarantee. Through integration of multi-source sensors and automatic control technology, data-driven management of the whole process of riprap and leveling is realized. Precise positioning of the construction ship and intelligent leveling of the leveling frame provide a stable reference for subsequent operations; dynamic adjustment of riprap parameters and position based on real-time sensing data significantly improves riprap uniformity; automatic start-stop control of the scraping mechanism ensures that the high standard of the pier top flatness is achieved. This method converts invisible underwater construction into a visible, controllable and optimized digital process, greatly reducing manual intervention and reducing operation risk, providing reliable foundation construction quality assurance for deep water infrastructure.

[0016] Second, the present application avoids the risk of leveling frame leveling failure caused by uneven base from the source. By performing full-coverage accurate measurement on the seabed foundation groove before the leveling frame is lowered, real and comprehensive base elevation data are obtained, providing a reliable basis for accurate calibration of the leveling frame. This measure effectively prevents secondary adjustment or even project rework caused by base inconsistency with design, improves the first adjustment success rate, and ensures the stability of the reference for subsequent riprap and leveling operations, laying a solid foundation for the entire high-precision construction from the initial stage.

[0017] Third, the present application ensures the internal structure quality of the rubble pier body from the material level. By strictly controlling the particle size range of the rubble and ensuring the continuity of the gradation, particles of different sizes can be embedded and extruded with each other and effectively fill the voids during the riprap falling and water flow impact process, thereby forming a whole with high density and uniform structure. This optimized material property provides a stable working base for subsequent scraping operations, significantly improves the overall stability and load bearing capacity of the formed pier body, and avoids weak and uneven settlement of the pier body caused by material separation.

[0018] Fourth, the present application can accurately determine the best time for starting and stopping scraping by continuously monitoring the flatness data and its change rate, and integrating the control system to avoid precision loss caused by early or late operation. The scraping mechanism runs at a constant speed along the preset track to ensure the consistency and full coverage of the operation. Full-process automatic control completely replaces the high-risk and low-efficiency underwater manual operation, eliminates human factor interference, significantly improves the scraping precision, efficiency and operation safety, and ensures that the pier top flatness meets the high standard once.

[0019] Fifth, the application can real-time perceive water flow changes and automatically adjust the amount of stone delivery by establishing a matching relationship between flow rate and riprap rate, effectively suppressing the phenomenon of stone dispersion caused by strong water flow and avoiding excessive accumulation under weak water flow. This dynamic adjustment strategy ensures that the stone can still be accurately deposited in the target area in a changing environment, significantly improving the uniformity and density of the riprap body and ensuring the final construction quality of the riprap body from the process control level.

[0020] Sixth, the application integrates dispersed construction data into a structured information stream with time sequence markers and realizes real-time remote monitoring of the shore base through a satellite link, completely breaking down the information barriers of offshore construction. Management personnel can fully grasp the situation on the scene, timely discover and handle abnormalities, and the complete electronic log provides a valuable data basis for subsequent quality analysis, responsibility definition and process optimization, greatly improving the modernization level and decision-making efficiency of offshore engineering management.

[0021] Seventh, the application can acutely identify signs of instability or erosion of the foundation under the support leg through fusion analysis of pressure sensors and attitude data, and automatically suspend operation and issue an alarm before an accident occurs. This active safety mechanism based on multi-parameter logical judgment changes the traditional passive post-remedy to active pre-prevention, effectively avoiding equipment overturning and engineering quality accidents, and providing reliable technical support for safe and efficient construction in complex seabed geological conditions.

[0022] Eighth, the application converts underwater video streams into high-precision digital elevation models through image processing and computer vision algorithms, realizing real-time, objective and quantitative evaluation of the elevation and flatness of the riprapping surface. This system completely replaces subjective judgment relying on the experience of divers, provides accurate data input for the automatic decision of the integrated control system, and ensures the timeliness and scientificity of construction parameter adjustment, which is a technical cornerstone for realizing high-precision intelligent control throughout the process.

[0023] Other advantages, objects and features of the application will be partially embodied in the following description, and partially understood by those skilled in the art through research and practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The workflow schematic diagram of one of the technical solutions of the application. DETAILED DESCRIPTION

[0025] The application will be further described in detail below with examples, so that those skilled in the art can implement it with reference to the description.

[0026] It should be noted that the experimental methods in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial sources unless otherwise specified. It should be particularly noted that the method provided by the present application is mainly aimed at gravel foundations with large construction area and high flattening precision, such as foundation cushion of immersed tunnel, riprap bed of gravity wharf, etc. For gravel cushion piers with small area (usually less than 10 m 2 ), such as some submarine pipeline support points, due to the large differences in construction technology, precision requirements and economy, the construction equipment and process can be simplified according to the actual situation, and the present application will not be described hereinafter.

[0027] As shown in Figure 1 , the present application provides a high-precision leveling construction method for deep-water foundation trench gravel piers, which proposes a systematic solution to the technical problems of difficult leveling of the top surface of the foundation trench gravel pier and significant influence of the marine environment. The traditional construction method mainly relies on underwater visual observation and manual measurement by divers, which not only has low efficiency and is difficult to ensure precision, but also has high risk for divers. The water surface commander cannot real-time master the state of underwater riprap, and can only rely on experience to operate, and cannot dynamically adjust the construction parameters according to the actual situation. In addition, the traditional method cannot quantitatively evaluate the elevation and flatness of the underwater filling body in real time, and can only be detected after the construction is completed, which is difficult to cope with the influence of dynamic environmental factors such as water flow and tidal level, resulting in difficulty in controlling the riprap precision.

[0028] The implementation of the method of the present application first accurately positions the RTK-GPS positioning system carried by the construction ship to the design pier axis, and anchors and positions. Then, the leveling frame equipped with an inertial navigation unit and a sonar height meter is lowered to the predetermined position of the seabed trench. During the lowering process, the sonar height meter continuously monitors the distance between the leveling frame and the bottom of the trench to ensure safe lowering. After the leveling frame is positioned, the three-dimensional attitude data fed back by the inertial navigation unit and the height data of the sonar height meter are used to remotely adjust the multiple legs of the leveling frame through the deck console hydraulic system, so that the top surface is accurately adjusted to the design elevation and kept horizontal.

[0029] Then, the telescopic riprap hopper integrated with an underwater camera and a flow rate sensor is lowered, and the distance between the outlet and the foundation surface is adjusted to be within 1.0-2.0 m. During the riprap process, the underwater camera captures the image of the spread and accumulation of gravel in real time, and the elevation and flatness data of the filling surface are extracted in real time through the image processing system. The flow rate sensor synchronously monitors the flow rate change at the outlet of the hopper. The integrated control system comprehensively receives the elevation, flatness and flow rate data, and automatically adjusts the length of the riprap guide pipe according to the real-time tidal level change and the elevation of the filling surface, dynamically maintains the distance between the outlet and the gravel surface within the set range. At the same time, the system controls the riprap point position by the ship anchoring positioning system according to the flatness data, supplements the stone material to the identified low-lying area, and realizes real-time feedback and optimization of the filling process.

[0030] After the stone covers the top surface of the leveling frame, start the high-frequency vibration leveling mechanism integrated on the leveling frame to remove the excess stone. After completing the construction of a single pier, hoist the leveling frame and the stone dumping hopper, and finally use a workboat to carry a multi-beam depth measurement system to conduct comprehensive scanning detection and acceptance of the constructed stone pier.

[0031] Compared with traditional methods, the present application significantly improves the accuracy and efficiency of underwater stone dumping and leveling through multi-sensor integration, real-time data feedback and automatic control, reduces the dependence on divers, improves the safety of operations, and effectively addresses the challenges brought by deep water dynamic environment.

[0032] The underwater high-definition camera integrated in the telescopic stone dumping hopper conduit continuously collects underwater video streams of stone accumulation and diffusion during the stone dumping process at a certain frame rate. These image data are transmitted in real time to the integrated control system on the deck of the construction ship through armored optical cable, and the following processing steps are performed: 1. Image preprocessing: Preprocess each received frame of image, including eliminating color distortion and scattering effect caused by water, enhancing contrast, and reducing noise points, to obtain clearer stone particle outlines.

[0033] 2. Feature point matching and three-dimensional point cloud generation: Use three-dimensional reconstruction algorithms such as binocular vision or structured light. If binocular cameras are used, match the same feature points in the images taken by the two cameras, and calculate the positions of these points in three-dimensional space by triangulation method. Finally, a three-dimensional point cloud dataset representing the current dumping surface morphology is generated.

[0034] 3. Digital elevation model establishment: Register and align the generated three-dimensional point cloud data with the design coordinate system of the leveling frame. Then, grid the discrete point cloud data to generate a continuous digital elevation model. The digital elevation model accurately reflects the elevation of each point on the dumping surface relative to the reference surface of the leveling frame.

[0035] 4. Data extraction and analysis: Based on the digital elevation model, calculate and output two key indicators in real time: one is the average elevation of the entire dumping area; the other is the flatness data, such as maximum height difference or root mean square error, which is used to measure the degree of surface fluctuation.

[0036] According to the change of tidal level and the elevation of the real-time dumping surface, automatically adjust the length of the telescopic stone dumping hopper conduit, drive the hydraulic actuator to act through real-time sensing, data fusion and logical judgment, and the control steps include: 1. Data acquisition and fusion: Continuously receive data from two independent sources: one is the real-time tidal level data sent by the tidal level sensor installed on the ship side; the other is the average elevation data of the dumping area calculated by the above image processing.

[0037] 2. Calculate the target length of the duct: The built-in control logic calculates the absolute water depth position that the duct outlet needs to maintain according to the following formula: Target outlet water depth = Real-time tidal level - (Average elevation of the dumping area + Preset hover height), where the preset hover height is a fixed value set by the engineer, ranging from 1.0-2.0m, aiming to optimize the trajectory of the rock falling and reduce dispersion. Then, according to the target outlet water depth and the fixed installation position of the rock dumping hopper on the ship, the target length required for the duct is calculated.

[0038] 3. Length adjustment execution: Compare the calculated target length with the current measured length of the duct. If there is a deviation, send a command to the hydraulic station to drive the hydraulic cylinder adjusting the telescopic duct to extend or shorten the duct until its actual length matches the target length. This process is automatically repeated according to the tidal rise and fall and the lifting of the dumping surface in all-weather construction, ensuring that the duct outlet is always dynamically maintained at the ideal height.

[0039] Based on real-time flatness data, the anchoring positioning system of the construction ship is controlled to move to adjust the rock dumping point, the operation steps include: 1. Flatness analysis and low-lying area identification: The integrated control system analyzes the real-time generated digital elevation model, and visually displays the high and low areas on the dumping surface through color rendering or contour identification. It automatically identifies areas with an elevation lower than the design elevation and a deviation exceeding the allowed threshold (e.g. 3cm), and marks them as "low-lying areas" to be supplemented.

[0040] 2. Generate rock dumping point compensation instructions: For each identified low-lying area, calculate its centroid's two-dimensional plane coordinates in the grading frame coordinate system. Then convert the coordinates into offset and direction relative to the construction ship.

[0041] 3. Fine-tune the ship's position: The integrated control system sends the compensation instructions to the anchoring positioning system of the construction ship (such as the DGPS dynamic positioning system or the full-rotation thruster system). The anchoring positioning system controls the cables or thrusters of the construction ship to make small-scale precise movements in the anchored state, aligning the outlet of the telescopic rock dumping hopper with the center coordinates of the identified low-lying area.

[0042] 4. Pointed rock dumping: After the construction ship moves into position, control the rock conveying system to dump rock in a specific, quantitative manner to the low-lying area. After the supplement is completed, the image processing system scans the area again to verify the supplement effect. If it still does not meet the requirements, repeat steps 2-4 until the flatness of the area meets the requirements.

[0043] Through the cyclic operation of the above three processes, high precision and high efficiency of rock dumping in deep water environment can be ensured.

[0044] In another embodiment of the present application, a high-precision leveling construction method for a deep-water foundation trench rockfill pier is provided. The rockfill used in the construction is sieved and proportioned, and the particle size is strictly controlled between 10-50 mm, and the gradation is ensured to be continuous. In the specific implementation, in the selected rockfill material, the particles with a particle size of 10-20 mm account for about 30%, the particles with a particle size of 20-40 mm account for about 50%, and the particles with a particle size of 40-50 mm account for about 20%. The continuously graded rockfill mixture is filled by a telescopic rockfill hopper. During the water flow impact and falling process, the rockfill particles of different particle sizes are embedded and extruded with each other, effectively reducing the voids between the particles, thereby forming a rockfill pier body with better integrity and more uniform internal structure. The subsequent scraping operation acts on a foundation bed with higher integrity, significantly improving the compactness and stability of the top surface of the finally formed rockfill pier.

[0045] In the traditional construction, a single particle size or a broken gradation rockfill is commonly used, and the single particle size rockfill with a particle size range of 20-40 mm is filled under the same deep water environment and current conditions. Due to the lack of fine particles to fill the voids between coarse particles and the lack of a sufficient proportion of coarse particles to form a skeleton, the filling body itself has a large porosity. During the filling process, especially under the action of water flow, the rockfill particles lack embedding force and are prone to relative displacement and separation. The internal structure of the formed rockfill pier body is loose, the compactness differs significantly in different areas, and the overall stability is poor.

[0046] In another embodiment of the present application, in the traditional deep-water foundation trench rockfill pier leveling construction, the scraping operation completely relies on the manual operation of divers underwater. The diver needs to dive underwater and manually control the scraping equipment to perform the scraping operation by observing and judging the elevation and flatness of the rockfill pier top surface with the naked eye and experience. This method is greatly affected by underwater visibility, diver physical strength and experience, the scraping precision is difficult to guarantee, the efficiency is low, and the diver faces high safety risks for long-term operation in a deep-water high-pressure environment. The surface command personnel cannot real-time master the underwater scraping progress and effect, and can only make decisions through intermittent feedback of the diver, and the overall construction process is poorly controllable.

[0047] In this embodiment, the scraping operation is automatically controlled by the integrated control system, and completely without the intervention of divers underwater. The start, operation and stop of the high-frequency vibration scraping mechanism integrated on the screed frame are all automatically managed by the integrated control system. The integrated control system continuously receives real-time flatness data processed by the underwater camera, and when it is monitored that the average elevation of the filling surface reaches the design elevation of the top surface of the screed frame, and the change rate of the real-time flatness data is less than 1 cm / s (preset change rate threshold) for 30 s continuously, the system automatically sends a start instruction to the high-frequency vibration scraping mechanism. The high-frequency vibration scraping mechanism immediately performs reciprocating scraping operation along the preset track of the screed frame at a fixed speed. The integrated control system continuously monitors the flatness data during the scraping process, and when the flatness deviation of the top surface of the pier body is not greater than 30 mm (preset difference threshold), the system automatically stops the scraping operation.

[0048] Compared with the traditional manual operation mode relying on divers, the present application realizes the automation of the entire scraping process through the integrated control system, eliminates the uncertainty of human operation, and significantly improves the scraping accuracy and consistency. At the same time, the underwater operation of divers is avoided, the construction risk is greatly reduced, and the overall construction efficiency and safety are improved.

[0049] In another embodiment of the present application, in the traditional deep water foundation trench rubble pier filling construction, the conveying rate of stone is usually set as a fixed value according to experience. During the construction process, the operator cannot real-time perceive the change of water flow velocity at the outlet of the telescopic filling hopper. When the current velocity increases, the rubble thrown at a fixed rate will be strongly scoured by the water flow, causing part of the rubble, especially the fine particles, to be carried by the water flow to a position far away from the target area, resulting in loss of stone and uneven distribution. On the contrary, when the current velocity decreases, the stone at a fixed rate may be excessively accumulated below the outlet, forming a local bump. This unevenness problem of the filling body caused by the change of water flow is difficult to avoid in the traditional method, directly affecting the compactness and overall stability of the rubble pier body.

[0050] The present embodiment realizes the dynamic adjustment of the stone conveying rate through the integrated control system. During the construction process, the flow rate sensor integrated on the telescopic filling hopper conduit continuously monitors the real-time flow rate data at the outlet of the hopper, and transmits the data to the integrated control system in real time. The integrated control system internally pre-stores a set of corresponding relationship table of flow rate and conveying rate, which defines the optimal stone conveying rate value corresponding to different flow rate intervals.

[0051] After receiving the real-time flow rate data, the integrated control system immediately queries the built-in corresponding relationship table, judges the interval to which the current flow rate belongs, and automatically adjusts the rate of the stone conveying system to the target value corresponding to the interval. For example, when the water flow speed is monitored to increase, the system will correspondingly reduce the conveying rate to reduce the impact of water flow on the falling gravel; when the water flow speed decreases, the system will increase the conveying rate to ensure the efficiency of the riprap and avoid over-high accumulation.

[0052] The entire process is fully automated and does not require human intervention, and can respond to dynamic changes in the water flow environment in real time. Compared with the traditional construction method of using a fixed riprap rate, the present application effectively suppresses the dispersion of gravel under the action of water flow by real-time sensing of water flow changes and intelligent adjustment of riprap parameters, ensuring that the stone can be more accurately deposited in the target area, thereby significantly improving the uniformity of the fill body and the overall construction quality.

[0053] In another embodiment of the present application, in the construction of a conventional deep-water foundation groove riprap pier, there are significant defects in the recording and management of construction data. Various key data, such as height data from a sonar height meter, attitude data from an inertial navigation unit, image data from an underwater camera, flow rate data from a flow rate sensor, and tide level data from a tide level sensor, are usually recorded by separate systems. These data are often stored in local devices on the construction vessel and managed in a scattered and offline manner. The operator needs to manually record the construction log and align the data from different sources in the later stage. This mode leads to missing, asynchronous and non-uniform data recording. More importantly, all these valuable construction process information is isolated in the offshore construction site, and the shore-based project management and technical team cannot obtain timely information. They have no idea about the real-time position of the construction vessel, the leveling state of the leveling frame, the progress of the riprap operation, and the current sea condition. They can only get an overview through the irregular radio reports from the ship personnel. Once there is a quality problem, it is extremely difficult to trace back the cause afterwards, because there is a lack of continuous, complete and time-stamped data records to restore the real construction scene. Remote monitoring and real-time decision guidance are out of the question. The entire construction process is almost a "black box" for a modern project management, and there is a huge management blind spot and quality risk.

[0054] The present embodiment has a data recording and remote transmission module built into the integrated control system. This module, as a core component of the integrated control system, automatically and continuously collects and records all sensor data during the entire construction process, all control instructions issued by the integrated control system, and the state information of the key equipment. All this information is given a uniform time stamp and packaged into a structured data file. Subsequently, through a satellite communication link with wide coverage, these packaged data are transmitted in real time and continuously to the shore-based monitoring center far away.

[0055] At the shore-based monitoring center, these data are received and parsed by specialized software. Management personnel can watch in real time through large display screens the precise position of the construction vessel, the three-dimensional attitude of the screed, the real-time digital elevation model of the dumped fill surface, the flow rate at the hopper outlet, the current tide level, and the stone delivery rate, and all other key parameters. The entire construction scene is transparently presented in a visual and digital manner. Any abnormal data or operation can be discovered at the first time. All data transmitted to the shore base are simultaneously permanently stored, forming a complete set of electronic construction logs that can be retrieved and traced at any time. Every step of operation and every parameter of any one rubble mound from the beginning to acceptance are recorded completely, providing a data basis for subsequent quality analysis, efficiency optimization, and responsibility definition.

[0056] Compared with the traditional method, the present embodiment upgrades the construction data management from the traditional mode of dispersion, offline, and post-repair to the digital management mode of centralization, online, and real-time transparency. It completely breaks down the information barrier between offshore construction and land management, enabling shore-based personnel to master the construction status as if they were on site, achieving real remote visual monitoring and full-process quality tracing, and greatly improving the modern management level and controllability of large-scale offshore engineering construction.

[0057] In another embodiment of the present application, the screed is seated and leveled by the legs. If there is a local weak layer under the seabed trench excavation surface, or the stability of the trench edge decreases due to excavation disturbance, then during the leveling of the screed or subsequent dumping and scraping operations, the legs of the screed may settle unevenly. This will directly damage the levelness and design elevation of the leveled screed, causing the entire high-precision construction process to fail, and even causing equipment safety accidents such as overturning of the screed. Even if the “elevation” of the trench excavation surface is rechecked by multi-beam sounding, it is only topographic information and cannot obtain the “mechanical properties” (bearing capacity, compactness) of the soil below the seabed. The construction vessel is in an unknown state at this point, which is a risky operation of blindly lowering the screed.

[0058] In traditional deepwater caisson construction, the stability of the leveling frame after sitting on the seabed completely depends on the prior measurement of the seabed topography and the experience of the operator. The operator cannot know the actual bearing capacity of the seabed under each leg of the leveling frame in real time. After the leveling frame is leveled, the operator has no idea whether the legs are sinking or the foundation is being eroded during the entire rock throwing and scraping operation. Once the soil layer under a certain leg has a local weak zone or a cavity is formed due to water erosion, the leg will suddenly sink, causing the entire leveling frame to tilt. This tilt not only immediately destroys the design elevation and levelness that have been adjusted, making all previous high-precision rock throwing and scraping operations meaningless, but also more dangerously, it can cause uneven stress on the leveling frame structure and cause the entire leveling frame to overturn, causing serious equipment safety accidents. Since all operations are carried out in deep water, post-remediation and equipment salvage will be extremely difficult and costly. The traditional method lacks effective early warning and immediate response mechanisms for such risks.

[0059] The present embodiment constructs a real-time foundation stability monitoring system through pressure sensors installed at the bottom of each leg of the leveling frame and an inertial navigation unit provided with the leveling frame. When the leveling frame is leveled, the integrated control system begins to continuously read the readings of each pressure sensor and the horizontal inclination data of the inertial navigation unit. The integrated control system has multiple preset thresholds, such as a first preset threshold corresponding to an abnormal decrease in leg pressure, a second preset threshold corresponding to an abnormal increase in pressure of other legs, and a third preset threshold corresponding to the maximum horizontal inclination allowed by the leveling frame. During construction, if the integrated control system detects that the pressure value of a certain leg decreases by more than the first preset threshold in a short period of time, while the pressure values of one or more adjacent legs increase by more than the second preset threshold, and the horizontal inclination data fed back by the inertial navigation unit also exceeds the third preset threshold, the system will immediately make a logical judgment. This combination of pressure redistribution accompanied by a change in posture clearly indicates that the foundation under the leg is losing stability.

[0060] Once the foundation is determined to be unstable, the integrated control system will automatically pause the current rock throwing or scraping operation and send an emergency alarm to the operator on the ship's deck console through the audible and visual alarm. The operator can quickly identify the risk location and type based on the alarm information. Compared to the traditional method of passively detecting after an accident occurs, the present embodiment allows the construction team to timely interrupt the operation at the incipient stage of the accident, thereby avoiding equipment damage and engineering quality accidents, and gaining valuable time for subsequent remedial measures.

[0061] In another embodiment of the present application, in the traditional deep water foundation trench rubble pier construction, the form of the underwater filling body is seriously dependent on the artificial observation and post-detection of divers. Divers need to dive underwater, observe and judge the rubble accumulation by naked eye and experience, and obtain limited elevation point data through manual measurement tools. This method is greatly affected by underwater visibility, diver physical strength and subjective experience, and cannot comprehensively, objectively and continuously quantify the evaluation of the filling surface form. The surface command personnel can only make decisions based on the intermittent and qualitative description of the divers, and cannot obtain accurate elevation and flatness data in real time. After the construction is completed, a work boat carrying a multi-beam depth sounding system is needed to scan and accept, and once the unqualified area is found, the remediation cost is extremely high and the construction period is seriously delayed. During the whole process, the adjustment of construction parameters is seriously lagging behind, and cannot respond to the dynamic influence of water flow and tidal level changes during the filling process, resulting in poor control precision of the flatness of the finally formed rubble pier top surface, which is difficult to meet the high standard installation requirements.

[0062] In the present embodiment, the specific implementation of real-time acquisition of elevation and flatness data of the filling surface is as follows: After the construction ship completes positioning and stays in position, the telescopic rubble hopper integrated with an underwater high-definition camera is lowered to the pier site construction area. The underwater high-definition camera has a preset frame rate threshold (frame rate of 10-30 frames / second) fixed collection frequency, which continuously obtains underwater video images formed by the falling, diffusion and accumulation of rubble during the rubble filling process. Video image data is uploaded in real time to the integrated control system on the deck of the construction ship through armored communication optical cable.

[0063] The integrated control system has an image processing unit, which sequentially performs the following operations on each received image: First, image preprocessing is performed. Preprocessing includes histogram equalization processing, which expands the contrast range of the image by redistributing the intensity values of the pixels in the image, making the light and dark details in the image more distinct. Preprocessing also includes scattering effect elimination processing based on a physical optical model, which digitally corrects the color distortion and blurring of the image by establishing a model of light attenuation and scattering in water, to restore the true color and clarity of the image, so that the outline and texture features of the rubble particles in the water are enhanced, facilitating subsequent machine recognition and matching.

[0064] The pre-processed images are fed into a three-dimensional reconstruction module. This module employs a binocular vision three-dimensional reconstruction algorithm. The implementation of this algorithm relies on a pair of binocular cameras that have been calibrated beforehand. The calibration parameters include the intrinsic parameters of the cameras, such as focal length, principal point coordinates, and distortion coefficients, as well as the extrinsic parameters, i.e., the relative position and pose between the two cameras. The algorithm first extracts feature points from both left and right images using a feature description algorithm such as SIFT or ORB to identify key points in the images. Then, feature point matching is performed, i.e., pairing feature points extracted from the previous camera image with those extracted from the subsequent camera image to find homonymous feature points representing the same physical point. For each pair of successfully matched feature points, their coordinates in three-dimensional space are calculated using the triangulation method. The calculation process of the triangulation method is based on the perspective projection model of the two cameras and their relative geometric relationship, and the real three-dimensional position is calculated by solving the pixel coordinate difference (i.e., disparity) of the feature points in the two images. All calculated three-dimensional points converge to form a dense three-dimensional point cloud dataset representing the current surface morphology of the embankment.

[0065] Then, a digital elevation model is established. The integrated control system aligns the generated three-dimensional point cloud data with the design coordinate system inherent to the grading machine. The alignment process is achieved by finding the correspondence between the point cloud data and the known control points in the design coordinate system, and calculating an optimal spatial transformation matrix (usually containing rotation and translation). After alignment, the system performs gridding processing on the discrete three-dimensional point cloud data, dividing the embankment area into regular grid cells. For each grid cell, if it contains multiple three-dimensional points, the average elevation is taken; if there are no data points in the grid cell (i.e., there is a gap), an interpolation algorithm such as inverse distance weighted interpolation or Kriging interpolation is used to calculate the elevation value of the grid cell based on the elevation values of the surrounding grid points. Through this process, a continuous digital elevation model covering the entire embankment area is generated. This digital elevation model is a two-dimensional matrix, and each element value in the matrix represents the elevation at that grid point.

[0066] Finally, data extraction is performed. Based on the generated digital elevation model, the integrated control system calculates the overall average elevation of the embankment area in real time, which is the arithmetic mean of the elevations of all grid points in the model. At the same time, the system calculates the flatness data to represent the degree of surface undulation, such as calculating the deviation of all grid point elevations from the average elevation and taking the root mean square value of these deviations as the flatness evaluation index, or directly finding the highest and lowest points in the model and calculating their difference as the maximum height difference.

[0067] Compared with the foregoing traditional method, the embodiment completely replaces the backward method of relying on the naked eye observation and manual measurement of divers by an automatic computer vision and image processing system. It converts the invisible dumping process under water into a digital elevation model graph on a large screen of a shore-based monitoring center, which can be observed in real time and quantified accurately, realizes the process controllability and real-time optimization of construction quality. Management personnel can instruct the integrated control system to automatically adjust the dumping point or construction parameters according to the real-time feedback of the elevation and flatness data, so as to ensure that each rockfill mound top surface can reach the high-precision flatness standard required by the design at one time, and avoid the huge cost and time loss caused by subsequent remediation.

[0068] Although the embodiments of the present application have been disclosed as above, they are not limited to the application listed in the specification and the embodiments, and can be applied to various fields suitable for the present application, and additional modifications can be easily made by those skilled in the art, and therefore the present application is not limited to specific details and examples shown and described herein, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. A deep water foundation trench rubble pier high-precision leveling construction method, characterized in that, The method comprises the following steps: S1, the construction ship moves to the design axis position of the construction pier position based on the RTK-GPS positioning signal and anchors; S2, the leveling frame carrying the inertial navigation unit and the echo sounder height measuring instrument is lowered to the top of the seabed trench construction pier, and the distance between the echo sounder height measuring instrument and the trench bottom is monitored in real time during the lowering; after being lowered to the base surface, the three-dimensional attitude data fed back by the inertial navigation unit and the height data fed back by the echo sounder height measuring instrument are used to remotely and hydraulically synchronously control the multiple supporting legs of the leveling frame through the control console, so that the top surface reaches the design elevation and remains horizontal; S3, the telescopic riprap hopper is lowered, the guide pipe of which is integrated with an underwater camera and a flow rate sensor, the distance between the hopper outlet and the base surface is adjusted to 1.0-2.0m, and the riprap is thrown into the leveling frame through the hopper; during the riprapping, the underwater camera captures the image of the spread and accumulation of the riprap and processes it to obtain the elevation and flatness data of the riprapping surface; the flow rate sensor monitors the flow rate at the hopper outlet; the tide level sensor monitors the tide level; the integrated control system receives the elevation, flatness, flow rate and tide level data of the riprapping surface, automatically adjusts the length of the guide pipe according to the tide level and the real-time riprapping surface elevation, and maintains the vertical distance between the hopper outlet and the riprapping surface at 1.0-2.0m; based on the flatness data, the ship anchoring positioning system is moved to adjust the riprapping point and supplement the riprap to the low-lying area; S4, after the riprap covers the top surface of the leveling frame, the high-frequency vibration scraping mechanism integrated in the leveling frame is started to scrape off the riprap exceeding the top surface; The start and stop and operation of the high-frequency vibration scraping mechanism are automatically controlled by the integrated control system, and the steps include: the integrated control system receives the real-time flatness data processed by the underwater camera, and when the average elevation of the riprapping surface reaches the design elevation of the top surface of the leveling frame and the real-time flatness data changes at a rate lower than a preset threshold, the integrated control system automatically sends a start command; the high-frequency vibration scraping mechanism reciprocally scrapes along the preset track at a fixed speed, and the integrated control system automatically stops the operation when the flatness deviation of the top surface of the pier body is not more than a preset difference threshold.

2. The high-precision construction method of a deep-water foundation caisson rock pier according to claim 1, characterized in that, Further comprising: S5, after the riprapping and leveling of a single riprap pier are completed, the leveling frame and the telescopic riprap hopper are lifted; S6, the working boat carrying the multi-beam sounding system is used to scan, detect and accept the constructed riprap pier; S7, steps S1-S6 are repeated to construct the next construction pier, until all the pier positions are constructed.

3. The high-precision construction method of a deep-water foundation caisson rock pier according to claim 1, characterized in that, Before the leveling frame is lowered, the multi-beam sounding system carried by the working boat is used to fully cover the seabed trench and recheck the elevation of the seabed trench excavation surface.

4. The high-precision construction method of a deep-water foundation caisson rock pier according to claim 1, characterized in that, In the riprapping step, the riprap particle size used is 10-50mm, and the gradation is continuous.

5. The high-precision construction method of a deep-water foundation caisson rock pier according to claim 1, characterized in that, In step S3, the integrated control system dynamically adjusts the conveying rate of the riprap based on the real-time flow rate data monitored by the flow rate sensor, specifically: the integrated control system has a corresponding relationship table of flow rate and conveying rate pre-stored therein, and the corresponding relationship table specifies the conveying rate value of the riprap corresponding to different flow rate intervals; the integrated control system queries the corresponding relationship table, automatically adjusts the conveying rate of the riprap to the corresponding target value according to the interval in which the real-time flow rate is located.

6. The high-precision construction method of a deep-water foundation caisson rock pier according to claim 1, characterized in that, The integrated control system is also provided with a data recording and remote transmission module, which is used to record the sensor data, control instructions and equipment state information during the whole construction process, and transmit the sensor data, control instructions and equipment state information to the shore-based monitoring center in real time through a satellite communication link.

7. The high-precision construction method of a deep-water foundation caisson rock pier according to claim 1, characterized in that, In step S2, the bottom of each leg of the screed is provided with a pressure sensor. After the top surface of the screed is adjusted to the design elevation and kept level, the integrated control system continuously monitors the pressure data of the bottom of each leg. If the decrease in the pressure value of a single leg exceeds a first preset threshold, while the increase in the pressure value of one or more other legs exceeds a second preset threshold, and the horizontal inclination data of the screed fed back by the inertial navigation unit exceeds a third preset threshold, the integrated control system determines that the foundation under the leg has been destabilized or eroded, and issues an alarm and automatically suspends the subsequent rock throwing operation.

8. The high-precision construction method of a deep-water foundation caisson rock pier according to claim 7, characterized in that, In step S3, the specific steps of obtaining the elevation and flatness data of the filling surface in real time include continuously collecting underwater video streams during the rock throwing process at a preset frame rate threshold through the underwater high-definition camera integrated on the telescopic rock throwing funnel conduit, and transmitting the video streams to the integrated control system in real time through the armored optical cable. The integrated control system sequentially performs the following processing on the received image sequence: Processing each frame of image includes histogram equalization and scattering effect elimination based on physical model to enhance image contrast and edge features; Based on binocular vision or structured light three-dimensional reconstruction algorithm, matching the same name feature points in left and right images, and calculating and generating three-dimensional point cloud data set representing the current filling surface morphology through triangulation method; Registering the three-dimensional point cloud data with the design coordinate system of the screed, and generating a continuous digital elevation model through gridding processing and interpolation algorithm; Based on the digital elevation model, calculating the average elevation of the whole filling area and the flatness data representing the degree of surface fluctuation in real time.

Images