Anti-silting construction method for port foundation bed

Abstract

The invention discloses a port foundation bed anti-back-silting construction method which comprises the steps that an adjustable grid plate sludge intercepting assembly composed of a wave-shaped grid plate and a hydraulic lifting stand column is erected on the periphery of a foundation bed construction area, and the wave-shaped grid plate is obliquely arranged on the hydraulic lifting stand column and composed of protruding parts and sunken parts which are alternately arranged; a flow guide device formed by connecting three groups of V-shaped flow guide units in series is arranged at the position 20 m away from the front side of the wave-shaped grid plate in the incident flow direction, and a rotatable base at the bottom of the flow guide device adjusts the flow guide angle according to the tide direction; a sludge thickness monitoring device is mounted on the back flow surface of the wave-shaped grid plate, and the hydraulic lifting stand column is controlled to lift the wave-shaped grid plate according to the monitoring condition; and after the lifting operation of the wave-shaped grid plate is completed, a jet flow type dredging ship is adopted for conducting fixed-point dredging along the back flow face, and a mud-water mixture is conveyed to an onshore treatment station. The method is mainly used for anti-silting construction of the port foundation bed.

Description

Technical Field

[0001] The present invention relates to the technical field of port engineering construction, and more specifically, to a port subgrade anti-silting construction method. Background Art

[0002] During the construction and maintenance of port projects, the problem of port bed siltation has been a serious problem for engineering personnel, posing a significant threat to the normal operation and structural stability of the port. The port bed has been in a complex marine environment for a long time. The flow of seawater, tidal changes and the movement of seabed sediment make the bed very prone to silting. Once silting occurs, the silt on the surface of the bed will continue to accumulate, which not only reduces the bearing capacity of the bed and affects the stability of port buildings, but also may cause the channel to become shallower, hinder the normal passage of ships, and increase the dredging cost and maintenance difficulty of the port. Conventional anti-siltation measures are not very effective in dealing with complex marine environments. For example, the simple interception devices used in the early days were fixed in structure and could not be adjusted according to changes in tides and water currents, making it difficult to effectively prevent the backflow of silt. At different tidal periods, the direction and speed of water flow vary greatly, and the fixed interception devices cannot adapt to such dynamic changes, causing some silt to bypass the interception devices and continue to deposit in the bed area. As for the monitoring of silt thickness, the traditional method relies on manual regular testing, which is not only inefficient, but also has large errors in the test results, and cannot accurately obtain the thickness information of the silt on the bed surface in real time. This makes it difficult for engineering personnel to take effective dredging measures in time, causing the silt accumulation problem to gradually worsen. In addition, in the dredging process, the previous dredging ship operation method lacked pertinence and failed to form an effective coordination with the bed anti-resilting system. During the dredging process, either the dredging was incomplete, leaving a large amount of silt on the bed surface, or the dredging was excessive, causing damage to the bed structure. It may also cause secondary pollution, and the pollutants originally deposited on the bed will be re-suspended in the seawater. In the process of solving the problem of port bed siltation, engineers are faced with many technical challenges. On the one hand, the complexity and variability of the marine environment make it difficult for any single anti-siltation technology to cope with all situations. To achieve effective control of water flow and silt movement, it is necessary to comprehensively consider multiple factors and develop a set of anti-siltation systems that can dynamically adapt to changes in the marine environment. On the other hand, how to achieve real-time and accurate monitoring of bed siltation, and how to organically combine monitoring data with anti-siltation and silt removal measures, are also urgent issues to be solved. In addition, it is equally challenging to develop silt removal technology that can both efficiently remove silt and avoid negative impacts on the bed and the marine environment. In summary, the problem of port bed siltation is serious, and the existing anti-siltation and dredging technologies have many shortcomings. There is an urgent need for a more efficient, intelligent and environmentally friendly port bed anti-siltation construction method to cope with the complex marine environment and ensure the safe operation and sustainable development of the port. Summary of the invention

[0003] Another purpose of the present invention is that the silting of the port bed will affect its stability and subsequent use. The existing anti-silting means are difficult to systematically solve the problems of silting monitoring, interception and cleaning. This technology aims to construct a comprehensive construction method covering interception, diversion, monitoring and silting, and effectively prevent and control the silting of the port bed.

[0004] If the diversion device is not designed properly, it will not be able to guide the water flow efficiently, thus reducing the anti-silting effect. This technology aims to improve its ability to guide the water flow and enhance the overall anti-silting effect by optimizing the structure and parameters of the diversion device.

[0005] If the materials and components of the guide device have poor performance, they are prone to corrosion and damage, shortening the service life and increasing maintenance costs. This technology aims to improve the durability and reliability of the guide device by selecting high-quality materials and optimizing component design.

[0006] If the anti-corrosion coating is not effective, the guide device is prone to corrosion. This technology aims to enhance the anti-corrosion performance of the guide device by designing a multi-layer composite structure anti-corrosion coating and optimizing the construction and curing process.

[0007] If the performance and preparation process of the fluorosilicone modified acrylate hydrophobic layer are not perfect, it will affect the hydrophobic and protective effects of the anti-corrosion coating. This technology aims to optimize its composition structure and preparation process to improve the hydrophobic performance and protective ability of the coating.

[0008] If the adjustable grid plate silt interception assembly is not properly installed, it is difficult to effectively intercept silt, and problems such as settlement and scouring may occur during the construction process. This technology aims to standardize the installation process of the adjustable grid plate silt interception assembly and improve its interception effect and stability.

[0009] If the construction parameters cannot be reasonably converted based on terrain data, it is impossible to arrange anti-siltation facilities in a targeted manner. This technology aims to optimize the arrangement of anti-siltation facilities by constructing a construction parameter conversion method based on three-dimensional terrain data.

[0010] If the dredging vessel cannot plan the operation path according to the risk level, it will lead to low dredging efficiency or incomplete dredging. This technology aims to improve the dredging efficiency and quality by establishing a dredging vessel operation path planning method based on risk level.

[0011] In order to achieve these purposes and other advantages according to the present invention, a port bed anti-silting construction method is provided, comprising the following steps: S1. An adjustable grating silt interception assembly is set up outside the base bed construction area. The adjustable grating silt interception assembly includes a wavy grating and a hydraulic lifting column. The wavy grating is composed of alternately arranged protrusions and recesses. The height of the protrusion is 60 cm, the depth of the recess is 40 cm, and the center distance between adjacent protrusions is 80 cm. The wavy grating is tilted on the hydraulic lifting column, and the lower end of the hydraulic lifting column is anchored under the seabed; S2. Install a silt thickness monitoring device on the backflow surface of the corrugated grating. The silt thickness monitoring device includes a laser thickness gauge, an acoustic Doppler velocity profiler and a turbidity sensor arranged at intervals. A laser thickness gauge is installed every 15 m. The turbidity sensor is installed 0.8 m above the laser thickness gauge. The sampling frequency of the turbidity sensor is 2 times per minute. The acoustic Doppler velocity profiler is installed in the depression of the grating to monitor the bottom water flow velocity in real time. When the laser thickness gauge detects that the silt thickness on the bed surface reaches 25 cm, the bottom water flow velocity is less than 0.3 m / s, and the turbidity of the water body is more than 50%, start the hydraulic lifting column to lift the corrugated grating as a whole by 40 cm. After lifting, the bottom of the corrugated grating maintains a gap of 20 cm with the seabed surface for 6 hours; S3. After the lifting operation of the corrugated grating is completed, a jet dredging vessel is used to perform fixed-point dredging along the back flow surface of the corrugated grating, and the mud-water mixture discharged by the jet dredging vessel is transported to an onshore processing station through a pipeline.

[0012] Preferably, in step S1, the installation of the adjustable grid sludge interception assembly comprises the following steps: A1. Start seabed topography scanning 24 hours before construction, use a multi-beam echo sounder to map the 50 m range around the base bed with a 0.5 m × 0.5 m grid accuracy, generate three-dimensional topographic scanning data, and mark high turbulence areas with velocity gradients > 0.3 m / s / m; A2. According to the 3D terrain scanning data, the corrugated grating is arranged on the downstream side of the high turbulence area. The axis of the corrugated grating forms a dynamic angle of β=5°~35° with the direction of maximum flow velocity. The spacing D between adjacent corrugated gratings is calculated according to the formula D=2H2+1.5H1, and the minimum spacing is not less than 4 m, where H2 is the water depth and H1 is the wave crest height of the corrugated grating. A3. Hydraulic lifting columns are constructed by vibration pile sinking method. The pile sinking rate is controlled at 0.5m / min. The penetration change is monitored in real time. When the penetration ΔS is ≤ 2cm for 10 consecutive hits, pile sinking is terminated. A4. The installation of the corrugated grating is divided into three levels of loading and debugging: a1. During the initial installation, adjust the inclination angle of the corrugated grid to θ1 = 55° ± 1°, maintain it for 12 hours and use a total station to monitor Measure the subgrade settlement; a2. In the secondary loading stage, the inclination angle of the corrugated grid is adjusted to θ2 = 60° ± 0.5°, the laser thickness gauge and turbidity sensor are started to monitor the siltation, and the acoustic Doppler velocity profiler is simultaneously activated to continuously scan the bottom flow velocity of the back flow surface; a3, in the third-level loading stage, the inclination angle of the corrugated grating is adjusted to θ3 = 65° ± 0.3°. When the acoustic Doppler current profiler detects that the standard deviation of the back flow velocity σ ≤ 0.1 m / s and lasts for 30 minutes, the inclination angle of the corrugated grating is fixed; A5. Dynamic control during construction period includes: b1. During the bedrock dumping operation, the wave-shaped grating is raised by 20 cm every day during the low tide period for 2 hours, and the peak of the low tide velocity is used to flush the bottom sediment; b2. When the multi-beam scanning depth sounder finds that the depth of the scour pit at the front of the wavy grid is greater than 1m, the lateral reinforcement of the pile foundation is triggered, and the jet grouting pressure is ≥2 MPa and the slurry diffusion radius is ≥0.8 m; b3. 6 hours before the dredging ship starts operation, the corrugated grating is lowered to 90% of the designed elevation to form a 2 m wide diversion channel. The dredging ship sails along the center line of the channel at a constant speed of 0.8 m / s.

[0013] Preferably, in step S1, a guide device is arranged 20 m in front of the wavy grating in the flow direction, the guide device is composed of three groups of V-shaped guide units connected in series, the V-shaped guide unit is welded by two arc-shaped guide wing plates, the curvature radius of the guide wing plates is consistent with the wave crest radius of the wavy grating, the opening angle of a single V-shaped guide unit is 120 degrees, the unit spacing is 1.5 times the length of the guide unit, and a rotatable base is arranged at the bottom of the guide unit, and the rotatable base adjusts the guide angle according to the tidal direction.

[0014] Preferably, the thickness of the guide wing plate is 1 / 25 of the wave crest height H1 of the corrugated grating plate and is not less than 15 mm.

[0015] Preferably, in step A1, after obtaining the three-dimensional terrain data, converting the three-dimensional terrain data into construction parameters specifically includes the following steps: c1. Use a multi-beam depth sounder to conduct a full coverage scan of the 50 m range outside the base bed, generate 0.5 m×0.5 m grid three-dimensional terrain data, with an elevation measurement accuracy of ±2 cm and a data acquisition density of ≥200 points / m²; c2. Based on the three-dimensional terrain data, the velocity gradient field is calculated through the fluid mechanics model, and the high turbulence area with velocity gradient > 0.3 m / s / m is marked and classified into risk levels: Level I risk area: flow velocity gradient is 0.3-0.5 m / s / m, the spacing of the diversion units is S=1.2L, where L is the length of the diversion unit; Level II risk area: flow velocity gradient is 0.5-0.8 m / s / m, additional diversion units are installed, and the spacing between diversion units is S=0.8L; Level III risk area: The flow velocity gradient is greater than 0.8 m / s / m. Additional diversion units are installed. The spacing between diversion units is S=0.6L. Anti-scour gabions are pre-buried and the anti-scour gabions are filled with block stone protection bottom layer. c3. Convert the three-dimensional terrain data and velocity gradient field into construction control parameters by: According to the risk level area divided by c2, the direction of the wavy grating axis is dynamically adjusted. The wavy grating axis and the water flow direction form a deviation angle of 5° to 15° in the level I risk area, the deviation angle in the level II risk area is increased to 15° to 25°, and the deviation angle in the level III risk area is set to 25° to 35°, and the projection of the wavy grating covers the pre-buried gabion bottom protection area; According to the risk level areas divided by C2, the anchoring depth of the hydraulic lifting columns is adjusted. In the level I risk area, the anchoring depth of the hydraulic lifting columns is 2.5 times the water depth; in the level II risk area, the anchoring depth of the hydraulic lifting columns is increased by 10% compared with that in the level I risk area; in the level III risk area, the anchoring depth of the hydraulic lifting columns is increased by 20% compared with that in the level I risk area.

[0016] Preferably, based on the risk level, the dredging vessel navigation system loads the risk area level generated by c2 in real time, and adjusts the operation path of the dredging vessel according to the risk area level, specifically: Level I risk area: The dredging vessel dredges parallel to the boundary line of the back flow surface of the wavy grating 1.5 m outward, and the speed of the dredging vessel is set at 1.0 m / s±0.1 m / s; Level II risk area: The dredging vessel dredges along the projection line of the concave part of the wave-shaped grid plate, and the speed of the dredging vessel is reduced to 0.8 m / s±0.1 m / s; Level III risk area: The dredging vessel uses the pre-buried gabion bottom layer as the center for spiral dredging. The speed limit of the dredging vessel is 0.6m / s±0.1m / s. The suction pipe of the dredging vessel is kept at a safe distance of 0.3m from the surface of the anti-scouring gabion. Among them, when the laser thickness gauge detects that the silt thickness gradient on the dredging path is greater than 5 cm / m, the dredging ship is triggered to automatically increase the operation track, and the path spacing is reduced to 50% of the original design.

[0017] The present invention has at least the following beneficial effects: First, the present invention constructs a comprehensive construction method that integrates interception, diversion, monitoring and silt removal. The adjustable grid plate silt interception assembly can effectively block silt, the diversion device guides the water flow to reduce silt accumulation, and the monitoring device provides real-time feedback on the silt status so that the grid plate can be lifted in time and silt removal operations can be carried out. This whole set of processes greatly improves the efficiency of anti-silting, ensures the stability of the base bed, extends the service life of port facilities, and reduces the cost of later maintenance; by optimizing the structure and parameters of the diversion device, it can better cooperate with the wavy grid plate. The arc-shaped guide wing plate and the specific guide groove design can guide the water flow more effectively. The dynamic compensation based on the PID algorithm can adjust the diversion angle in real time to adapt to tidal and water flow changes, improve the ability to control the water flow, further enhance the overall anti-silting effect, and reduce the deposition of silt in the base bed area.

[0018] Second, the present invention uses duplex stainless steel to make the diversion wing plate, and optimizes the components such as the hydraulic rotating base, which improves the durability and reliability of the diversion device; standardizes the installation process of the adjustable grid plate silt interception assembly, and makes the arrangement of the wavy grid plate and the hydraulic lifting column more scientific through seabed terrain scanning and reasonable parameter setting. The three-level loading and debugging ensures the stability of the grid plate, and the dynamic regulation during the construction period can respond to various construction problems in a timely manner, improves the interception effect and stability of the interception system, and ensures the smooth progress of the construction process.

[0019] Third, the present invention converts construction parameters based on three-dimensional terrain data, and can reasonably arrange anti-siltation facilities according to different risk levels. Dynamically adjust the axial direction of the wave-shaped grating and the anchoring depth of the hydraulic lifting column to make the anti-siltation system more targeted, improve the efficiency and effect of the layout of anti-siltation facilities, and reduce engineering costs; plan the operation path of the dredging ship based on the risk level to make the dredging operation more targeted. Adjusting the speed and operation mode of the dredging ship according to different risk levels can improve the efficiency and quality of dredging, avoid the problem of insufficient or excessive dredging, and at the same time ensure the safety of the dredging process and reduce damage to the base bed and anti-scouring gabions.

[0020] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0022] The present invention provides a port bed anti-silting construction method. The adjustable grating silt interception assembly in the present invention refers to a device composed of a wavy grating and a hydraulic lifting column, which is used to intercept silt backflow. The diversion device is a device installed in the flow direction of the wavy grating to guide the water flow and reduce the deposition of silt in the bed area. The silt thickness monitoring device is composed of a laser thickness gauge, an acoustic Doppler flow profiler and a turbidity sensor, which can monitor the silt thickness on the bed surface, the bottom water flow velocity and the turbidity of the water body in real time.

[0023] S1. When implementing the port bed anti-silting construction, the first step is to set up an adjustable grating silt interception assembly outside the bed construction area. The adjustable grating silt interception assembly includes a wavy grating and a hydraulic lifting column. The wavy grating is composed of alternating raised parts and recessed parts. The raised part protrudes 60 cm in height, the recessed part is 40 cm deep, and the center distance between adjacent raised parts is 80 cm. You can choose a hydraulic lifting column that is suitable for the marine environment, anchor its lower end under the seabed, and then install the wavy grating on the hydraulic lifting column in an inclined state. With this design, the wavy grating can disrupt the water flow and effectively intercept silt.

[0024] S2. Install a silt thickness monitoring device on the backflow surface of the wavy grating. Install a laser thickness gauge every 15 m, and install a turbidity sensor 0.8 m above each laser thickness gauge. The turbidity sensor samples twice per minute. Install an acoustic Doppler velocity profiler in the depression of the grating to monitor the bottom water flow velocity in real time. When the laser thickness gauge detects that the silt thickness on the surface of the base bed reaches 25 cm, and the bottom water flow velocity (obtained by the acoustic Doppler velocity profiler) is less than 0.3 m / s, and the turbidity of the water body reaches more than 50%, start the hydraulic lifting column to lift the wavy grating as a whole by 40 cm. After lifting, the bottom of the wavy grating maintains a gap of 20 cm with the seabed surface for 6 hours, so that part of the water flows through the gap to carry away the silt.

[0025] S3. After the lifting operation of the corrugated grating is completed, a jet dredging vessel is used to perform fixed-point dredging along the backflow surface of the corrugated grating. The jet dredging vessel uses high-pressure water flow to impact the sludge to suspend it, and then sucks the mud-water mixture through the sludge suction device and transports it to the onshore treatment station through a pipeline for treatment; The wavy grating is made of duplex stainless steel, which is composed of austenite and ferrite, and has good strength and corrosion resistance. When water flows through, the raised and recessed parts change the direction and speed of the water flow, causing turbulence in the water flow, reducing the ability of the water flow to carry silt, and thus intercepting silt. According to the principles of hydrodynamics, this irregular shape increases the resistance of the water flow and promotes the sedimentation of silt; during long-term use, the wavy grating is regularly cleaned with an underwater robot or an unmanned submersible equipped with a high-pressure water gun to remove attached organisms; The cylinder of the hydraulic lifting column is made of nickel-based alloy, with a nickel content of no less than 62%. Nickel-based alloy has long been widely used in the field of marine engineering due to its excellent corrosion resistance in many corrosive environments. At the same time, the wavy grid is installed obliquely on the hydraulic lifting column. The two cooperate with each other to effectively disperse the impact of seawater when intercepting silt, reduce the direct impact on the lifting column, reduce the risk of structural damage, and ensure stability when used in seawater. Through the silt thickness monitoring device and dynamic regulation during the construction period, the working status of the hydraulic lifting column can be understood in real time. If abnormalities are found, such as displacement or corrosion caused by seawater scouring, timely measures can be taken to repair or adjust it to ensure its continuous and stable operation in seawater. The laser emitted by the laser thickness gauge adopts pulse code modulation, which makes the laser signal more anti-interference. At the receiving end, digital signal processing technology is used to reduce noise and enhance the reflected light signal. The laser thickness gauge uses nano coating, which can effectively prevent seawater and microorganisms from contacting the surface of the equipment, greatly extending the service life of the protective layer. Nano coating has been successfully applied to some marine monitoring equipment, significantly reducing the corrosion rate of the equipment.

[0026] Turbidity sensors are relatively mature, and their working principles mainly include optical scattering method, transmission method, etc. These technologies can measure seawater turbidity more accurately. Compared with some high-end marine monitoring equipment, turbidity sensors are relatively low in cost and will not bring excessive economic pressure to the project when deployed on a large scale. This allows turbidity sensors to be widely deployed in different locations in port bed monitoring to obtain more comprehensive seawater turbidity data and improve the accuracy and reliability of monitoring. Turbidity sensors use remote control technology, and technicians can calibrate the sensors on shore through wireless communication and adjust the calibration parameters in real time.

[0027] Acoustic Doppler current profiler (ADCP) can accurately measure the velocity and direction of seawater at different depths. In the port area, the water flow is complex and changeable. Factors such as tides, wind and waves, and ship navigation will affect the water flow state. ADCP can obtain these dynamically changing water flow data in real time to help staff understand the three-dimensional structure of the water flow around the port bed. During the tidal change process, ADCP can accurately monitor the changes in water flow velocity at different depths during high tide and low tide. The technology of acoustic Doppler current profiler is quite mature and has been widely used in marine scientific research, marine engineering, and water conservancy engineering. Its measurement principle is based on the Doppler effect. It calculates the water flow velocity by transmitting and receiving sound waves, and has high accuracy and reliability. For noise and outliers in the original data, common data processing software (such as MATLAB, etc.) provides a variety of filtering algorithms, such as median filtering, mean filtering, etc. Selecting a suitable filtering method according to the characteristics of the data can effectively remove noise and outliers; in terms of analyzing velocity data at different depths, you can refer to existing oceanographic research results and methods.

[0028] By adopting this technical solution, the present invention constructs a complete port bed anti-silting system through the above series of construction steps. The system can monitor the silting condition of the bed in real time, and effectively reduce the amount of silting of the bed through various means such as interception and silting, ensure the stability of the bed, reduce maintenance costs, extend the service life of port facilities, and ensure the normal operation of the port; the present invention installs wavy gratings, hydraulic lifting columns, laser thickness gauges, acoustic Doppler flow profilers, and turbidity sensors. The wavy gratings cooperate with the hydraulic lifting columns to effectively intercept silt and reduce the amount of silting of the port bed. The laser thickness gauge, acoustic Doppler flow profiler, and turbidity sensor monitor in real time, accurately grasp the silt accumulation situation, make the silting operation more targeted, avoid unnecessary silting work, and reduce the frequency and cost of silting. In the long run, it can significantly reduce the human, material and financial inputs required for port maintenance; reducing the siltation of the base bed can reduce the risk of erosion and damage to the foundation of port buildings, enhance the stability of port facilities, extend the service life of facilities such as docks and piers, and reduce the number of repairs and reconstructions of facilities; accurate monitoring and efficient anti-siltation measures ensure the smooth passage of waterways, reduce ship waiting time and navigation obstacles, improve port cargo throughput capacity, and increase port operating income; unified construction standards and processes can improve construction efficiency and reduce construction time and labor costs in large-scale applications. For example, the installation of corrugated gratings and hydraulic lifting columns, large-scale construction can achieve standardized operations and reduce construction risks and costs. Although the initial equipment installation and system construction costs are high, in the long run, the reduced maintenance costs and increased operating income far exceed the initial investment.

[0029] In another technical solution, a multi-beam echo sounder is a device that can measure the underwater topography and quickly obtain water depth data over a large area. Penetration refers to the depth to which the pile body enters the soil under the action of the hammer.

[0030] In step S1, the installation of the adjustable grid sludge interception assembly includes the following steps: A1. 24 hours before construction, start the multi-beam echo sounder to survey the 50m range around the base bed with a grid accuracy of 0.5 m×0.5 m, generate three-dimensional terrain scanning data, and mark the flow velocity gradient greater than 0.3 m / s / m as a high turbulence area.

[0031] A2. According to the 3D terrain scanning data, the corrugated grating is arranged on the downstream side of the high turbulence area, and the axis of the corrugated grating forms a dynamic angle of 5° to 35° with the direction of maximum flow velocity. The spacing between adjacent corrugated gratings is determined according to the water depth H2 and the crest height H1 of the corrugated grating, and the minimum spacing is not less than 4 m; A3. Hydraulic lifting columns are constructed by vibration pile driving method. The pile driving rate is controlled at 0.5 m / min. The penetration change is monitored in real time. When the penetration ΔS is ≤ 2 cm for 10 consecutive hits, the pile driving is terminated. A4. The installation of the corrugated grating is divided into three levels of loading and debugging: a1. During the initial installation, adjust the inclination angle θ2 of the corrugated grid to 55°, with an allowable error of 1°, maintain for 12 hours, and use a total station to monitor the subgrade settlement; a2. In the secondary loading stage, the inclination angle θ2 of the corrugated grid is adjusted to 60°, with an error of 0.5° allowed. The laser thickness gauge and turbidity sensor are started to monitor the siltation, and the acoustic Doppler velocity profiler is activated to continuously scan the bottom flow velocity of the back flow surface; a3, the third-level loading stage, the inclination angle θ2 of the corrugated grating is adjusted to 65°, with an allowable error of 0.3°. When the acoustic Doppler velocity profiler detects that the standard deviation of the back flow velocity σ≤0.1 m / s and lasts for 30 min, the inclination angle of the corrugated grating is fixed; A5. Dynamic control during construction period includes: b1. During the bedrock dumping operation, the wave-shaped grating is raised by 20 cm every day during the low tide period for 2 hours, and the peak of the low tide velocity is used to flush the bottom sediment; b2. When the multi-beam scanning depth sounder finds that the depth of the scour pit at the front of the wavy grid exceeds 1 m, the lateral reinforcement of the pile foundation is triggered, the jet grouting pressure is not less than 2 MPa, and the slurry diffusion radius is not less than 0.8 m; b3. 6 hours before the dredging ship starts operation, the corrugated grating is lowered to 90% of the designed elevation to form a 2m wide diversion channel. The dredging ship sails along the center line of the channel at a constant speed of 0.8 m / s.

[0032] By adopting this technical solution, the present invention improves the stability and interception effect of the adjustable grid silt interception assembly by standardizing the installation process of the adjustable grid silt interception assembly and implementing dynamic regulation during the construction period, thereby ensuring the smooth progress of the construction process and reducing construction risks.

[0033] In another technical solution, the hydraulic rotating base is a device installed at the bottom of the diversion unit to adjust the angle of the diversion unit, which is composed of a double-acting hydraulic cylinder and an angle feedback encoder; the PID control algorithm is a commonly used control algorithm that can dynamically compensate the diversion angle according to the real-time flow rate value; In step S1, a diversion device is arranged 20 m in front of the wavy grid in the flow direction. The diversion device is composed of three groups of V-shaped diversion units connected in series, the opening angle of a single V-shaped diversion unit is 120 degrees, and the unit spacing is 1.5 times the length of the diversion unit. A rotatable base is installed at the bottom of the diversion unit, and the base is equipped with a device that can time according to tidal changes, and adjust the diversion angle according to the tidal direction (the adjustment interval of the diversion angle is determined according to the characteristics of the local tidal cycle, such as in the semi-diurnal tidal zone, the diversion angle is adjusted every 6 hours, such as in the full-day tidal zone, the diversion angle is adjusted every 12 hours), thereby guiding the water flow and reducing the amount of silt transported to the base bed area; The V-shaped guide unit of the guide device is welded from two arc-shaped guide wings. The curvature radius of the guide wing must be consistent with the wave crest radius of the corrugated grating, so that the guide device and the corrugated grating can better cooperate and improve the guiding effect of the water flow; A hydraulic rotating base is installed at the bottom of the guide unit. The double-acting hydraulic cylinder in the hydraulic rotating base is responsible for driving the guide unit to rotate and adjust the guide angle. The angle feedback encoder monitors the angle of the guide unit in real time and feeds the information back to the control system. The guide unit spacing is set to 2 times the guide unit length. The guide unit length L and the wave crest height H1 of the wavy grating meet the requirement that L is 3 times H1. When adjusting the diversion angle, a dynamic compensation mechanism based on the PID control algorithm is used. The control system calculates the compensation amount based on the real-time flow velocity value monitored by the acoustic Doppler flow profiler, and the compensation amount is 0.15 times the real-time flow velocity value. By controlling the extension and contraction of the double-acting hydraulic cylinder, the diversion angle can be accurately adjusted, so that the diversion device can better adapt to the dynamic changes of the water flow; During the implementation process, the two arc-shaped guide wings of the V-shaped guide unit are rolled and formed with duplex stainless steel (duplex stainless steel is a stainless steel composed of austenite and ferrite, with good strength and corrosion resistance). The thickness of the wing is determined by 1 / 25 of the wave crest height H1 of the corrugated grid, and the thickness shall not be less than 15 mm. With the characteristics of duplex stainless steel, the durability and corrosion resistance of the guide wing are effectively enhanced; The double-acting hydraulic cylinder of the hydraulic rotating base is equipped with an energy storage compensation module (the energy storage compensation module is installed on the double-acting hydraulic cylinder and can store and replenish hydraulic oil to ensure the stable operation of the cylinder). The accumulator volume is 1.2 times the stroke volume of the hydraulic cylinder. The surface of the piston rod of the hydraulic cylinder is laser-clad with a nickel-based tungsten carbide coating, which greatly improves the wear resistance of the piston rod. The working pressure of the hydraulic cylinder is set to 12 MPa to ensure that it can stably push the guide unit to adjust the angle; The length L of the guide unit is 3 times the height H1 of the wave crest of the wavy grating, and the unit spacing S is based on 2 times of L, with an allowable error range of 0.1 times L. On the frontal surface of the guide vane, an isosceles trapezoidal groove with a top width of 10 mm, a bottom width of 15 mm, and a depth of 8 mm is opened. The groove spacing is 0.6 times the height H1 of the wave crest of the wavy grating, with an allowable error of 0.01 times H1. The groove axis is deflected 12° relative to the normal of the guide vane, with an allowable error of 0.5°. The water-based anti-corrosion coating in the groove is composed of a nano-ceramic bottom layer and a graphene-modified surface layer. The nano-ceramic bottom layer enhances the adhesion of the coating, and the graphene-modified surface layer improves the anti-corrosion performance of the coating. The diversion device can effectively guide the flow of seawater, change the direction and speed of the flow, and reduce the deposition of silt in the port bed area; the diversion device, the corrugated grating, the silt thickness monitoring device, etc. together constitute a complete anti-silting system. In conjunction with the corrugated grating, the diversion device guides the water flow to pass through the grating more smoothly, enhancing the interception effect of the grating on silt. When the monitoring device detects an abnormal situation, the diversion device can adjust the angle according to the feedback, optimize the water flow state, and improve the anti-silting performance of the entire system. In practical applications, this collaborative working mode can effectively cope with the complexity of the seawater environment and improve the efficiency and reliability of anti-silting; the design and manufacturing technology of the diversion device is relatively mature and has been widely used in marine engineering, water conservancy engineering and other fields. Its structural design and material selection have a relatively complete theoretical and practical basis. For example, in the construction of some large cross-sea bridges, the diversion device is used to guide the water flow and protect the bridge pier foundation from scouring. Although the installation of diversion devices requires a certain amount of initial investment, in the long run, the benefits they bring are significant. Effectively reducing silt accumulation can reduce port dredging costs and avoid damage to port facilities and maintenance costs caused by bed siltation. It can improve port operating efficiency, reduce ship waiting time, and increase cargo throughput. In large-scale applications, as production and installation technologies mature, unit costs can be further reduced, improving cost-effectiveness.

[0034] By adopting this technical solution, the present invention improves the ability to guide water flow and enhances the anti-silting effect by optimizing the structure and parameters of the diversion device. The dynamic compensation mechanism based on the PID algorithm enables the diversion device to adjust the diversion angle in real time according to the change of water flow, reduce the deposition of silt in the bed area, and further ensure the stability of the port bed; the present invention greatly improves the durability and reliability of the diversion device by selecting high-quality materials, optimizing component design and coating structure, reducing the frequency of equipment maintenance and replacement, and can also operate stably in complex marine environments and continue to play an anti-silting role.

[0035] In another technical solution, the fluid mechanics model is a mathematical model based on the principles of fluid mechanics, which is used to simulate the movement of water flow. The risk level is a classification of the risk of siltation in the bed area based on the flow velocity gradient.

[0036] c1. Use a multi-beam depth sounder to conduct a full coverage scan of the 50 m range outside the base bed to generate 0.5 m×0.5 m grid three-dimensional terrain data. The elevation measurement accuracy is controlled at ±2 cm, and the data acquisition density is not less than 200 points / m²; c2. Based on the three-dimensional terrain data, the velocity gradient field is calculated with the help of fluid mechanics model, and the velocity gradient greater than 0.3 m / s / m is marked as a high turbulence area, and the risk level is divided: in the level I risk area with a velocity gradient of 0.3 - 0.5 m / s / m, the spacing between the diversion units is 1.2 times the length of the diversion unit; in the level II risk area with a velocity gradient of 0.5 -0.8 m / s / m, additional diversion units are added, and the spacing between the diversion units is 0.8 times the length of the diversion units; in the level III risk area with a velocity gradient greater than 0.8 m / s / m, additional diversion units are also added, and the spacing between the diversion units is 0.6 times the length of the diversion units, and anti-scour gabions are pre-buried, and the block stone protective base layer is filled in the anti-scour gabions.

[0037] c3. Convert the three-dimensional terrain data and velocity gradient field into construction control parameters by: According to the risk level area, the direction of the wavy grating axis is dynamically adjusted. In the level I risk area, the wavy grating axis forms a 5° to 15° deviation angle with the water flow direction. In the level II risk area, the deviation angle increases to 15° to 25°. In the level III risk area, the deviation angle is set to 25° to 35°, and the wavy grating projection covers the pre-buried gabion bottom protection area. At the same time, adjust the anchoring depth of the hydraulic lifting column. In the level I risk area, the anchoring depth is 2.5 times the water depth. In the level II risk area, the anchoring depth is increased by 10% compared with the level I risk area. In the level III risk area, the anchoring depth is increased by 20% compared with the level I risk area.

[0038] By adopting this technical solution, the present invention converts construction parameters based on three-dimensional terrain data, realizes the targeted arrangement of anti-siltation facilities, improves the adaptability of the anti-siltation system to different risk areas, improves the anti-siltation effect, and reduces engineering costs.

[0039] In another technical solution, the dredging ship navigation system is a system that provides navigation services for the dredging ship and guides the dredging ship to perform dredging operations according to a predetermined path. The silt thickness gradient refers to the change in silt thickness per unit length.

[0040] Based on the risk level, the dredging ship navigation system loads the risk area level generated by C2 in real time and adjusts the operation path of the dredging ship according to the risk area level, specifically: In the level I risk area, the dredging boat extends 1.5 m outward along the boundary line of the back flow surface of the wave-shaped grating plate and dredges in parallel. The boat speed is set at 1.0 m / s, with an allowable error of 0.1 m / s. In the risk area of ​​level II, the dredging vessel shall carry out dredging operations along the projection line of the concave part of the wavy grating plate in a serpentine path (a serpentine path is a path shape similar to the crawling trajectory of a snake, mainly a movement trajectory that turns back and forth left and right (or up and down) in a plane. For example, the dredging vessel swings left and right along the projection line of the concave part of the wavy grating plate, like a zigzag shape). The ship speed is reduced to 0.8 m / s, and an error of 0.1 m / s is allowed; In the Level III risk area, the dredging vessel uses a spiral path (a spiral path is a path shape that rotates around a center point and moves toward or away from the center. It is a continuous curve, like the shape of a spring) with the pre-buried gabion protective layer as the center for dredging operations. The ship speed is limited to 0.6m / s, and an error of 0.1m / s is allowed. The dredging vessel's sludge suction pipe maintains a safe distance of 0.3m from the surface of the anti-scour gabion.

[0041] Among them, when the laser thickness gauge detects that the silt thickness gradient on the dredging path exceeds 5 cm / m, it triggers the dredging ship to automatically increase the operation track, and the path spacing is reduced to 50% of the original design.

[0042] By adopting this technical solution, the present invention adjusts the operating path of the dredging ship based on the risk level, making the dredging operation more targeted, improving the dredging efficiency and quality, avoiding the problems of insufficient or excessive dredging, ensuring the safety of the dredging operation, and reducing the damage to the base bed and anti-scouring gabions.

[0043] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A port bed anti-silting construction method, characterized in that: The following steps are involved: S1. An adjustable grating silt interception assembly is set up outside the base bed construction area. The adjustable grating silt interception assembly includes a wavy grating and a hydraulic lifting column. The wavy grating is composed of alternately arranged protrusions and recesses. The height of the protrusion is 60 cm, the depth of the recess is 40 cm, and the center distance between adjacent protrusions is 80 cm. The wavy grating is tilted on the hydraulic lifting column, and the lower end of the hydraulic lifting column is anchored under the seabed; S2. Install a silt thickness monitoring device on the backflow surface of the corrugated grating. The silt thickness monitoring device includes a laser thickness gauge, an acoustic Doppler velocity profiler and a turbidity sensor arranged at intervals. A laser thickness gauge is installed every 15 m. The turbidity sensor is installed 0.8 m above the laser thickness gauge. The sampling frequency of the turbidity sensor is 2 times per minute. The acoustic Doppler velocity profiler is installed in the depression of the grating to monitor the bottom water flow velocity in real time. When the laser thickness gauge detects that the silt thickness on the bed surface reaches 25 cm, the bottom water flow velocity is less than 0.3 m / s, and the turbidity of the water body is more than 50%, start the hydraulic lifting column to lift the corrugated grating as a whole by 40 cm. After lifting, the bottom of the corrugated grating maintains a gap of 20 cm with the seabed surface for 6 hours; S3. After the lifting operation of the corrugated grating is completed, a jet dredging vessel is used to perform fixed-point dredging along the back flow surface of the corrugated grating, and the mud-water mixture discharged by the jet dredging vessel is transported to an onshore processing station through a pipeline.

2. The port bed anti-silting construction method according to claim 1, characterized in that: In step S1, the installation of the adjustable grid plate silt interception assembly includes the following steps: A1. Start seabed topography scanning 24 hours before construction, use a multi-beam echo sounder to map the 50 m range around the base bed with a 0.5 m × 0.5 m grid accuracy, generate three-dimensional topographic scanning data, and mark high turbulence areas with velocity gradients > 0.3 m / s / m; A2. According to the 3D terrain scanning data, the corrugated grating is arranged on the downstream side of the high turbulence area. The axis of the corrugated grating forms a dynamic angle of β=5°~35° with the direction of maximum flow velocity. The spacing D between adjacent corrugated gratings is calculated according to the formula D=2H2+1.5H1, and the minimum spacing is not less than 4 m, where H2 is the water depth and H1 is the wave crest height of the corrugated grating. A3. Hydraulic lifting columns are constructed by vibration pile sinking method. The pile sinking rate is controlled at 0.5m / min. The penetration change is monitored in real time. When the penetration ΔS is ≤ 2cm for 10 consecutive hits, pile sinking is terminated. A4. The installation of the corrugated grating is divided into three levels of loading and debugging: a1. During the initial installation, adjust the inclination angle of the corrugated grid to θ1 = 55° ± 1°, maintain it for 12 hours and use a total station to monitor Measure the subgrade settlement; a2. In the secondary loading stage, the inclination angle of the corrugated grid is adjusted to θ2 = 60° ± 0.5°, the laser thickness gauge and turbidity sensor are started to monitor the siltation, and the acoustic Doppler velocity profiler is simultaneously activated to continuously scan the bottom flow velocity of the back flow surface; a3, in the third-level loading stage, the inclination angle of the corrugated grating is adjusted to θ3 = 65° ± 0.3°. When the acoustic Doppler current profiler detects that the standard deviation of the back flow velocity σ ≤ 0.1 m / s and lasts for 30 minutes, the inclination angle of the corrugated grating is fixed; A5. Dynamic control during construction period includes: b1. During the bedrock dumping operation, the wave-shaped grating is raised by 20 cm every day during the low tide period for 2 hours, and the peak of the low tide velocity is used to flush the bottom sediment; b2. When the multi-beam scanning depth sounder finds that the depth of the scour pit at the front of the wavy grid is greater than 1m, the lateral reinforcement of the pile foundation is triggered, and the jet grouting pressure is ≥2 MPa and the slurry diffusion radius is ≥0.8 m; b3. 6 hours before the dredging ship starts operation, the corrugated grating is lowered to 90% of the designed elevation to form a 2 m wide diversion channel. The dredging ship sails along the center line of the channel at a constant speed of 0.8 m / s.

3. The port bed anti-silting construction method according to claim 1, characterized in that: In step S1, a guide device is arranged 20 m in front of the wavy grating in the flow direction, the guide device is composed of three groups of V-shaped guide units connected in series, the V-shaped guide unit is welded by two arc-shaped guide wing plates, the curvature radius of the guide wing plates is consistent with the wave crest radius of the wavy grating, the opening angle of a single V-shaped guide unit is 120 degrees, the unit spacing is 1.5 times the length of the guide unit, and a rotatable base is arranged at the bottom of the guide unit, and the rotatable base adjusts the guide angle according to the tidal direction.

4. The port bed anti-silting construction method according to claim 3, characterized in that: The thickness of the guide wing plate is 1 / 25 of the wave crest height H1 of the corrugated grid plate and is not less than 15 mm.

5. The port bed anti-silting construction method according to claim 4, characterized in that: In step A1, after obtaining the three-dimensional terrain data, the three-dimensional terrain data is converted into construction parameters, which specifically includes the following steps: c1. Use a multi-beam depth sounder to scan the entire 50 m range around the base bed, generate 0.5 m × 0.5 m grid three-dimensional terrain data, with an elevation measurement accuracy of ±2 cm and a data acquisition density of ≥200 points / m²; c2. Based on the three-dimensional terrain data, the velocity gradient field is calculated through the fluid mechanics model, and the high turbulence area with velocity gradient > 0.3 m / s / m is marked and classified into risk levels: Level I risk area: flow velocity gradient is 0.3-0.5 m / s / m, the spacing of the diversion units is S=1.2L, where L is the length of the diversion unit; Level II risk area: flow velocity gradient is 0.5-0.8 m / s / m, additional diversion units are installed, and the spacing between diversion units is S=0.8L; Level III risk area: The flow velocity gradient is greater than 0.8 m / s / m. Additional diversion units are installed. The spacing between diversion units is S=0.6L. Anti-scour gabions are pre-buried and the anti-scour gabions are filled with block stone protection bottom layer. c3. Convert the three-dimensional terrain data and velocity gradient field into construction control parameters by: According to the risk level area divided by c2, the direction of the wavy grating axis is dynamically adjusted. The wavy grating axis and the water flow direction form a deviation angle of 5° to 15° in the level I risk area, the deviation angle in the level II risk area is increased to 15° to 25°, and the deviation angle in the level III risk area is set to 25° to 35°, and the projection of the wavy grating covers the pre-buried gabion bottom protection area; According to the risk level areas divided by C2, the anchoring depth of the hydraulic lifting columns is adjusted. In the level I risk area, the anchoring depth of the hydraulic lifting columns is 2.5 times the water depth; in the level II risk area, the anchoring depth of the hydraulic lifting columns is increased by 10% compared with that in the level I risk area; in the level III risk area, the anchoring depth of the hydraulic lifting columns is increased by 20% compared with that in the level I risk area.

6. The port bed anti-silting construction method according to claim 5, characterized in that: Based on the risk level, the dredging ship navigation system loads the risk area level generated by C2 in real time and adjusts the operation path of the dredging ship according to the risk area level, specifically: Level I risk area: The dredging vessel dredges parallel to the boundary line of the back flow surface of the wavy grating 1.5 m outward, and the speed of the dredging vessel is set at 1.0 m / s±0.1 m / s; Level II risk area: The dredging vessel dredges along the projection line of the concave part of the wave-shaped grid plate, and the speed of the dredging vessel is reduced to 0.8 m / s±0.1 m / s; Level III risk area: The dredging vessel uses the pre-buried gabion bottom layer as the center for spiral dredging. The speed limit of the dredging vessel is 0.6 m / s±0.1 m / s. The suction pipe of the dredging vessel is kept at a safe distance of 0.3m from the surface of the anti-scouring gabion. Among them, when the laser thickness gauge detects that the silt thickness gradient on the dredging path is greater than 5 cm / m, the dredging ship is triggered to automatically increase the operation track, and the path spacing is reduced to 50% of the original design.