Seabed Sand Mining Pit Repair Control Method and System Based on Marine Dredged Mud

Abstract

This application relates to the technical field of seabed sand mining pit restoration, and discloses a control method and system for seabed sand mining pit restoration based on marine dredged mud. The method includes: conducting surveying and mapping and environmental analysis of the seabed sand mining pit, obtaining three-dimensional terrain data and improving the dredged mud; formulating a filling plan based on data analysis and establishing a transportation system combining barges and pipelines; filling materials in layers and carrying out ramming and grouting; constructing a three-layer protection structure, adding gabion cages and energy dissipation devices in high-risk areas; evaluating the restoration effect through a monitoring network and forming an evaluation database. This application uses marine dredged mud as the main material, realizes the efficient and stable restoration of the seabed sand mining pit through scientific improvement treatment and layered filling technology, combined with multi-level protection measures and a perfect monitoring and evaluation system.

Description

Technical Field

[0001] This application relates to the technical field of seabed sand mining pit restoration, and particularly to a control method and system for seabed sand mining pit restoration based on marine dredged mud. Background Art

[0002] Seabed sand mining activities are widely carried out due to engineering requirements such as construction and reclamation. However, this behavior has caused a large number of seabed sand mining pits, seriously damaging the marine ecosystem and seabed topography. Traditional seabed sand mining pit restoration methods mainly include natural restoration methods, artificial filling methods, and combined methods, etc. The natural restoration method relies on the natural sedimentation process to slowly fill the sand mining pit, with a long cycle and being uncontrollable; the artificial filling method usually uses materials such as sand and gravel to directly fill the pit, with high costs and large resource consumption; the combined method combines artificial measures and natural processes, but lacks a systematic technical solution. At the same time, with the increase in marine dredging projects, a large amount of dredged mud needs to be disposed of. Traditional methods such as marine dumping and landfill on land not only occupy resources but may also cause secondary pollution.

[0003] The main deficiencies in the existing technology are as follows: First, there is a lack of a systematic solution for using dredged mud to restore sand mining pits, and the recycling of resources cannot be achieved; second, the stability of the filling material is poor, and it is easily washed away under marine hydrodynamic conditions, resulting in an unsustainable restoration effect; third, the improvement treatment of the filling material during the restoration process is insufficient, which may lead to the release of pollutants; fourth, the protection measures are imperfect and cannot cope with the differential hydrodynamic conditions in different regions; fifth, there is a lack of an effective monitoring and evaluation system, making it difficult to scientifically evaluate the restoration effect and conduct timely maintenance. These problems have severely restricted the effect and popularization of seabed sand mining pit restoration work. Summary of the Invention

[0004] This application provides a control method and system for seabed sand mining pit restoration based on marine dredged mud, which is used to use marine dredged mud as the main material, and through scientific improvement treatment and layered filling technology, combined with multi-level protection measures and a perfect monitoring and evaluation system, to achieve the efficient and stable restoration of seabed sand mining pits.

[0005] In a first aspect, the present application provides a method for controlling the repair of a seabed sand mining pit based on marine dredged mud. The method for controlling the repair of a seabed sand mining pit based on marine dredged mud includes: conducting topographic surveying and environmental sample collection and analysis on the seabed sand mining pit to obtain three-dimensional topographic data of the sand mining pit, and improving the marine dredged mud to obtain repair materials; analyzing a filling plan based on the three-dimensional topographic data and the repair materials to generate a target filling plan, and constructing a transportation system that combines barge transportation and pipeline transportation; filling the repair materials into the sand mining pit in layers of bottom layer, middle layer, and surface layer based on the transportation system, and performing vibration compaction and underwater grouting treatment on each layer of filling body to obtain a filling structure; constructing a three-layer protection structure on the surface of the filling structure, and adding gabion cages and energy dissipation structures in high-scour-risk areas to obtain an erosion-resistant surface system; evaluating the repair effect of the erosion-resistant surface system according to a preset monitoring network to obtain a repair effect evaluation database.

[0006] In a second aspect, the present application provides a control system for repairing a seabed sand mining pit based on marine dredged mud. The control system for repairing a seabed sand mining pit based on marine dredged mud includes:

[0007] A collection module for conducting topographic surveying and environmental sample collection and analysis on the seabed sand mining pit to obtain three-dimensional topographic data of the sand mining pit, and improving the marine dredged mud to obtain repair materials;

[0008] An analysis module for analyzing a filling plan based on the three-dimensional topographic data and the repair materials to generate a target filling plan, and constructing a transportation system that combines barge transportation and pipeline transportation;

[0009] A filling module for filling the repair materials into the sand mining pit in layers of bottom layer, middle layer, and surface layer based on the transportation system, and performing vibration compaction and underwater grouting treatment on each layer of filling body to obtain a filling structure;

[0010] A construction module for constructing a three-layer protection structure on the surface of the filling structure, and adding gabion cages and energy dissipation structures in high-scour-risk areas to obtain an erosion-resistant surface system;

[0011] An evaluation module for evaluating the repair effect of the erosion-resistant surface system according to a preset monitoring network to obtain a repair effect evaluation database.

[0012] In a third aspect, there is provided a control device for repairing a seabed sand mining pit based on marine dredged mud, including: a memory and at least one processor, wherein instructions are stored in the memory; the at least one processor calls the instructions in the memory so that the control device for repairing a seabed sand mining pit based on marine dredged mud executes the above-mentioned method for controlling the repair of a seabed sand mining pit based on marine dredged mud.

[0013] In a fourth aspect, a computer-readable storage medium is provided, in which instructions are stored, and when they run on a computer, the computer is made to execute the above-described method for controlling the repair of a seabed sand mining pit based on marine dredged mud.

[0014] In the technical solution provided by this application, the steps of conducting topographic surveying and environmental sample collection and analysis on the seabed sand mining pit have constructed a comprehensive and accurate three-dimensional topographic model and an environmental assessment system, providing an accurate data basis for subsequent repair. At the same time, targeted improvement treatment is carried out on marine dredged mud, realizing the resource utilization of dredged mud and solving the problem of dredged mud disposal; based on the three-dimensional topographic data and repair materials, the filling scheme is analyzed, and artificial intelligence algorithms are applied to simulate and predict the hydrodynamic conditions and sediment migration laws, generating a target filling scheme for a specific environment, and constructing a precisely positioned transportation system, greatly improving the construction accuracy and efficiency; the layered filling technology is combined with vibration compaction and underwater grouting treatment to form a filling body with stable structure, enhancing the overall bearing capacity and anti-deformation ability; the three-layer protection structure design is combined with gabion cages and energy dissipation structures in high-risk areas, constructing an all-round anti-erosion surface system, significantly improving the anti-scour ability and long-term stability of the repaired area under extreme hydrodynamic conditions; the pre-set monitoring network is combined with data processing algorithms to realize the scientific evaluation and dynamic management of the repair effect. Through the intelligent processing of a large amount of spatial data, the accurate analysis and prediction of complex seabed environments are realized, improving the pertinence and scientific nature of the scheme. In the anti-scour performance assessment, a correlation model between hydrodynamic parameters and material properties is established, realizing the precise matching of protection requirements in different regions, and an anomaly detection algorithm is applied in the monitoring data processing to improve the data quality and early warning accuracy. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for description in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic diagram of an embodiment of the method for controlling the repair of a seabed sand mining pit based on marine dredged mud in an embodiment of this application;

[0017] Figure 2 It is a schematic diagram of an embodiment of the control system for the repair of a seabed sand mining pit based on marine dredged mud in an embodiment of this application;

[0018] Figure 3 It is a schematic block diagram of the structure of the device for controlling the repair of a seabed sand mining pit based on marine dredged mud in an embodiment of the present invention. Detailed implementation manners

[0019] An embodiment of the present application provides a method and system for controlling the repair of a seabed sand mining pit based on marine dredged mud. Terms such as "first", "second", "third", "fourth", etc. (if any) in the specification, claims and the above-mentioned drawings of the present application are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments described here can be implemented in an order other than those illustrated or described here. In addition, the term "including" or "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or devices.

[0020] For ease of understanding, the specific process of the embodiment of the present application is described below. Please refer to Figure 1 An embodiment of the method for controlling the repair of a seabed sand mining pit based on marine dredged mud in the embodiment of the present application includes:

[0021] Step S101: Conduct topographic surveying and environmental sample collection and analysis on the seabed sand mining pit to obtain three-dimensional topographic data of the sand mining pit, and perform improvement treatment on the marine dredged mud to obtain repair materials;

[0022] Step S102: Analyze the filling scheme based on the three-dimensional topographic data and the repair materials to generate a target filling scheme, and construct a transportation system that combines barge transportation and pipeline transportation;

[0023] Step S103: Fill the repair materials into the sand mining pit in layers of bottom layer, middle layer, and surface layer based on the transportation system, and perform vibration compaction and underwater grouting treatment on each layer of filling body to obtain a filling structure;

[0024] Step S104: Construct a three-layer protection structure on the surface of the filling structure, and add gabion cages and energy dissipation structures in high-scour-risk areas to obtain an erosion-resistant surface system;

[0025] Step S105: Evaluate the repair effect of the erosion-resistant surface system according to the preset monitoring network to obtain a repair effect evaluation database.

[0026] It can be understood that the execution subject of the present application can be a control system for repairing a seabed sand mining pit based on marine dredged mud, or a terminal or a server. Specifically, it is not limited here. The embodiment of the present application is described by taking the server as the execution subject as an example.

[0027] Specifically, a multi-beam sonar and a side-scan sonar system are used to map the seabed sand mining pits. The multi-beam sonar measures the water depth data at different positions by emitting multiple acoustic beams and receiving echo signals; the side-scan sonar scans the seabed by emitting fan-shaped acoustic beams to obtain the bottom sediment reflection intensity information. The navigation speed of the survey vessel is controlled at 3 - 5 knots to ensure data accuracy. The collected original bathymetric data is processed by marine geographic information system software to remove noise points, supplement missing data and perform coordinate transformation, generating three-dimensional terrain data of the sand mining pit, including key parameters such as pit depth, slope, and area. At the same time, multiple bottom sediment sampling points are set inside and around the sand mining pit, and bottom sediment samples with a depth of up to 30 cm are collected for laboratory analysis to determine environmental quality parameters such as grain size distribution, organic matter content, and heavy metal content. When treating the dredged mud, multiple representative samples are first taken for physical property and chemical composition analysis to determine physical parameters such as moisture content, density, and plasticity index, as well as the content of heavy metals and organic pollutants, and classified and rated to obtain the characteristics data of the dredged mud. Different treatment agents are added according to the type of pollution: solidifying agents and stabilizing agents are added to the dredged mud polluted by heavy metals to cause chelation reactions between heavy metal ions and stabilizing agents, reducing their mobility; oxidants and catalysts are added to the dredged mud with high organic pollutant content to promote the decomposition of organic pollutants. Finally, aggregate and fiber materials are added to enhance the strength, and permeable materials and modifiers are added to adjust the drainage performance to obtain the repair material.

[0028] Based on the three-dimensional terrain data, the hydrodynamic conditions in the sand mining pit area are analyzed to analyze the influence degree of local tidal currents, waves, ocean currents and other factors on the filling materials. Through hydrodynamic calculations, the incipient velocity and transport law of sediments under different water flow conditions are determined, and combined with the physical characteristics of the repair materials, the stability parameters required for the filling materials in each area are calculated. The sand mining pit is divided into filling units according to the filling area zoning scheme, and the filling thickness, material ratio and construction time sequence of each unit are determined. The filling principle of "first deep then shallow, first inside then outside" is adopted. First, the deepest part of the pit bottom is filled, gradually expanding towards the pit wall and the edge, and a settlement space of 10 - 15% is reserved. The transportation route and method of the repair materials are designed. When the distance between the storage location of the repair materials and the sand mining pit exceeds 10 kilometers, a combination of barge transportation and pipeline transportation is used. The barge is equipped with a GPS positioning system and an automatic bathymetric system. The pipeline system is made of wear-resistant materials, with a pipe diameter of not less than 300 mm, and an adjustable diffuser is designed at the end to control the release speed and range.

[0029] The repair materials are filled into the sand mining pit in layers through a transportation system. When filling the bottom layer, the repair materials mixed with aggregate are directionally placed into the deepest part of the sand mining pit, with a filling thickness of 1.5 - 2.5 meters. Then, underwater vibration compaction equipment is used for vibration treatment, and the vibration frequency and amplitude are adjusted according to the density of the filling materials to increase the compactness of the filling body. The middle layer is filled with the repair materials mixed with a curing agent in a partitioned and segmented manner, with a thickness of 0.8 - 1.2 meters, forming a stepped filling structure to enhance the interlayer bonding. The underwater grouting treatment is carried out on the middle layer filling body. The grouting points are arranged in a grid pattern with a spacing of 2 - 3 meters, and the grouting pressure is controlled at 0.2 - 0.3 MPa to form a grid-shaped reinforcement system. The surface layer is filled with a mixed material of improved dredged mud and fine sand, with a thickness of 0.5 - 0.8 meters. The area in contact with the pit wall is connected by grid anchors, which penetrate into the pit wall by 0.5 - 1 meter to prevent the filling body from separating from the pit wall. A three-layer protection structure is constructed. First, a mixture of fine sand and clay with a fine particle size is prepared as the transition layer material and laid on the surface of the filling structure to form a transition protection layer with a thickness of 0.2 - 0.3 meters. An anti-scour test is carried out on the transition protection layer to measure the material loss rate under simulated water flow conditions and calculate the anti-scour performance index. Gravel and cementitious materials are mixed and covered on the transition protection layer to form the middle protection layer with a thickness of 0.3 - 0.5 meters. When the anti-scour performance index is lower than the set threshold, the proportion of the cementitious material is increased for reinforcement treatment. Natural materials similar to the surrounding seabed environment are selected to cover the middle protection layer to form the surface protection layer with a thickness of 0.3 - 0.4 meters, so that the surface smoothly transitions to the elevation of the surrounding seabed. High-scour risk areas are identified through the analysis of water flow effects. In these areas, gabion cages with a size of 1 m × 1 m × 0.5 m are laid, filled with hard stones with a particle size of 50 - 100 mm. The gabion cages are tightly connected by connecting wires, and the edges are buried more than 0.5 meters into the bottom layer. An energy dissipation device composed of riprap or concrete blocks is set up to divert and reduce the energy of the incoming water flow.

[0030] Evaluate the repair effect through a pre - installed monitoring network. Install settlement monitoring points, water flow monitoring devices and pore pressure sensors at key positions to collect settlement data, water flow parameters and pore water pressure data. Process the monitoring data, eliminate outliers, and calculate the settlement rate, water flow velocity change and pressure change trend. For example, the data recorded by the settlement monitoring points show that the settlement rate gradually decreases from the initial 8 mm / day to 3 mm / day within 28 days after filling, and the total settlement is about 120 mm, within the range of the reserved settlement; the pore water pressure data show that the pressure gradually stabilizes, indicating that the consolidation process is proceeding normally. Measure the surface morphology change through underwater sonar scanning, calculate the erosion depth and scope, and evaluate the integrity of the protection structure. According to the stability determination and anti - erosion effect evaluation, grade the repaired area, and mark the areas that need to be strengthened or reinforced. Integrate the monitoring data, stability determination results, anti - erosion effect evaluation and subsequent maintenance area identification to construct a repair effect evaluation database, including time - series data and spatial distribution data, which is convenient for long - term tracking and evaluation of the repair effect.

[0031] In the embodiment of the present application, the steps of topographic surveying and mapping and environmental sample collection and analysis of the seabed sand - mining pit have constructed a comprehensive and accurate three - dimensional topographic model and environmental assessment system, providing an accurate data basis for subsequent repair. At the same time, targeted improvement treatment of marine dredged mud has realized the resource utilization of dredged mud and solved the problem of dredged mud disposal; based on the three - dimensional topographic data and repair materials for filling scheme analysis, applying artificial intelligence algorithms to simulate and predict the hydrodynamic conditions and sediment migration laws, generating a target filling scheme for a specific environment, and constructing a precisely positioned transportation system, greatly improving the construction accuracy and efficiency; the layered filling technology combined with vibration compaction and underwater grouting treatment has formed a filling body with stable structure, enhancing the overall bearing capacity and anti - deformation ability; the three - layer protection structure design combined with the application of gabion cages and energy - dissipating structures in high - risk areas has constructed an all - round anti - erosion surface system, significantly improving the anti - scouring ability and long - term stability of the repaired area under extreme hydrodynamic conditions; the combination of the pre - installed monitoring network and data - processing algorithms has realized the scientific evaluation and dynamic management of the repair effect. Through the intelligent processing of a large amount of spatial data, accurate analysis and prediction of complex seabed environments have been achieved, improving the pertinence and scientificity of the scheme. An association model between hydrodynamic parameters and material properties has been established in the anti - scouring performance evaluation, realizing the precise matching of protection requirements in different regions, and applying anomaly detection algorithms in the monitoring data processing to improve the data quality and warning accuracy.

[0032] In a specific embodiment, the process of executing step S101 may specifically include the following steps:

[0033] The multi-beam sonar system and side-scan sonar system are used to survey the seabed sand mining pits. The survey data is processed by performing three-dimensional modeling through marine geographic information system software to obtain three-dimensional terrain data;

[0034] Multiple bottom sediment sample collection points are set inside and around the sand mining pits. Bottom sediment samples at a specific depth are collected from each point, and the samples are analyzed in the laboratory to obtain environmental quality parameters;

[0035] Based on the terrain data and environmental quality parameters, a state evaluation index system for the sand mining pits is constructed, and the sand mining pits are evaluated by region to obtain the division of repair priorities and difficulty levels;

[0036] The physical properties of the dredged mud samples are detected and the chemical compositions are analyzed. The dredged mud is classified and rated according to the engineering applicability index and environmental safety index to obtain the characteristics data of the dredged mud;

[0037] According to the characteristics data of the dredged mud, a solidification and stabilization agent is added to the heavy metal-polluted dredged mud for solidification and stabilization treatment, and an oxidant and a catalyst are added to the organic-polluted dredged mud for chemical oxidation treatment to obtain harmless dredged mud;

[0038] Aggregate and fiber materials are added to the harmless dredged mud for strength enhancement treatment, and permeability materials and modifiers are added to adjust the drainage performance to obtain repair materials.

[0039] Specifically, the multi-beam sonar system is a marine exploration device that emits multiple sound beams through an array transmitter and receives the echo reflected from the seabed. Multiple water depth points on a survey line on the seabed can be obtained in one scan, forming a fan-shaped measurement area. The side-scan sonar system emits fan-shaped sound beams to both sides of the seabed, receives the reflected signals from different positions on the seabed, and obtains information on the seabed topography and bottom sediment type. During the survey, the survey vessel sails at a stable speed of 3-5 knots, keeping the distance between survey lines not exceeding 3 times the water depth to ensure that the data coverage rate reaches over 90%. The collected original survey data includes information such as water depth values, geographic coordinates, and reflection intensities, and needs to be processed through marine geographic information system software, including steps such as data cleaning, noise filtering, coordinate transformation, and data interpolation. First, the outliers that deviate significantly from the surrounding points are removed, then the Kriging interpolation method is used to fill the data blank areas, and finally, a three-dimensional terrain model of the sand mining pit is constructed by the Triangulated Irregular Network (TIN) method to accurately calculate parameters such as the area, volume, maximum depth, and slope of the sand mining pit.

[0040] After completing the topographic survey, multiple bottom sediment sample collection points need to be set inside and around the sand mining pit. The layout of the points follows the principle of representativeness. Usually, several points are set at the bottom of the pit, on the pit wall, and in the surrounding area. The spacing between the points is determined according to the area of the sand mining pit, generally 50 - 100 meters. A grab sampler or a gravity corer is used to collect bottom sediment samples with a depth of not less than 30 cm from each point, and the weight of each sample is about 2 kg. The collected samples are sealed and sent to the laboratory for analysis. The analysis items include particle size distribution (measured by a laser particle size analyzer), organic matter content (measured by the potassium dichromate oxidation method), heavy metal content (measured by atomic absorption spectrophotometry or inductively coupled plasma mass spectrometry), etc. The data obtained through analysis are the environmental quality parameters, which are used to evaluate the bottom sediment environmental status of the sand mining pit. Based on the three-dimensional topographic data and environmental quality parameters, a state evaluation index system for the sand mining pit is constructed to conduct a zonal evaluation of the sand mining pit. The index system includes two major categories: topographic indexes and environmental indexes. Topographic indexes include the depth recovery coefficient (the ratio of the maximum depth of the sand mining pit to the depth of the surrounding natural seabed), the slope stability coefficient (the ratio of the slope of the sand mining pit to the critical stable slope), etc. Environmental indexes include the bottom sediment quality index (the comprehensive evaluation value of the heavy metal pollution degree), the water quality status index (the comprehensive evaluation value of parameters such as dissolved oxygen and turbidity), etc. By assigning weights to each index and calculating the comprehensive score, a zonal evaluation of the sand mining pit is carried out, which is divided into high-priority areas (areas with large depth, steep slope, and serious environmental pollution), medium-priority areas, and low-priority areas. At the same time, the repair difficulty level is determined according to the topographic complexity and bottom sediment conditions.

[0041] Comprehensive quality testing of marine dredged mud samples is the key to ensuring the performance of the repair materials. First, collect at least 5 representative dredged mud samples, and the weight of each sample is not less than 2 kg. Conduct physical property tests on the samples, including water content (measured by the drying method), particle size distribution (measured by sieving method and hydrometer method), density (measured by the pycnometer method), plasticity index and liquidity index (measured by the limit water content method), etc. At the same time, conduct chemical composition analysis to determine the organic matter content, nutrient element content, sulfide content, pH value, etc. Of particular importance is to conduct an environmental risk assessment to detect the heavy metal content (copper, lead, zinc, cadmium, mercury, arsenic, etc.) and the concentration of persistent organic pollutants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, etc.) in the dredged mud. Classify and rate the dredged mud according to the engineering applicability indexes (strength, compressibility, permeability, etc.) and environmental safety indexes (pollutant content, biological toxicity, etc.) to obtain the characteristic data of the dredged mud.

[0042] According to the dredged mud characteristic data, differential improvement treatments are adopted for different types of pollution. For dredged mud with severe heavy metal pollution, solidification / stabilization technology is used for treatment. Solidifying agents (such as cement, lime, fly ash, etc., with an addition ratio of 5 - 10%) and stabilizing agents (such as modified clay, zeolite, etc., with an addition ratio of 3 - 5%) are added to the dredged mud, and they are fully mixed through a special mixing device, with the reaction time controlled within 24 - 48 hours. The solidification / stabilization process reduces the bioavailability and mobility of pollutants through mechanisms such as physical encapsulation (encapsulating pollutants within the solidified body), chemical fixation (chemical reactions occur between pollutants and stabilizing agents to form poorly soluble compounds), and ion exchange (heavy metal ions are adsorbed by stabilizing agents). For dredged mud with a high content of organic pollutants, chemical oxidation technology is adopted. Oxidants (such as hydrogen peroxide, persulfate, etc., with an addition ratio of 3 - 5%) and catalysts (such as iron salts, manganese salts, etc., with an addition ratio of 0.5 - 1%) are added to promote the oxidation and decomposition of organic pollutants. At the same time, a pH regulator is added to maintain the reaction system within the optimal pH range (usually neutral or weakly alkaline). The strength of the harmlessly treated dredged mud is enhanced and its drainage performance is adjusted. Aggregates (such as sand, crushed stone, etc., with an addition ratio of 5 - 15%) and fiber materials (such as polypropylene fiber, glass fiber, etc., with an addition ratio of 3 - 7%) are added to improve the shear strength and stability of the dredged mud through the skeleton effect and fiber reinforcement. At the same time, permeable materials (such as sand, zeolite, etc., with an addition ratio of 5 - 10%) and modifiers (such as cement, lime, etc., with an addition ratio of 2 - 3%) are added to improve the drainage performance of the dredged mud and accelerate the consolidation process. After the above series of treatments, the dredged mud is transformed into an engineering material that meets the requirements for the repair of submarine sand mining pits, and its shear strength, stability, erosion resistance, and environmental compatibility all reach the design standards.

[0043] In a specific embodiment, the process of executing step S102 may specifically include the following steps:

[0044] Analyze the hydrodynamic conditions in the sand mining pit area for the three-dimensional terrain data, calculate the influence degrees of tidal current, wave, and ocean current on the filling material, and obtain the hydrodynamic influence evaluation result;

[0045] Calculate the sediment migration law based on the hydrodynamic influence evaluation result, and combine with the physical properties of the repair material to determine the stability parameters of the filling material in each area, and obtain the filling area zoning plan;

[0046] Divide the sand mining pit into multiple filling units according to the filling area zoning plan, determine the specific filling thickness, material ratio, and construction time for each filling unit, and obtain the project implementation plan;

[0047] Optimize the project implementation plan, calculate the connection method between each filling unit, and obtain the target filling plan with reserved settlement space;

[0048] Determine the optimal transportation route based on the spatial relationship between the storage location of the repair material and the sand excavation pit, design the barge specifications, loading capacity and positioning system, and obtain the marine transportation plan;

[0049] Design the pipeline transportation system based on the marine transportation plan, determine the pipe diameter, flow velocity, transportation pressure and diffuser parameters, and construct a transportation system combining barge transportation and pipeline transportation.

[0050] Specifically, extract the geometric characteristic parameters of the sand excavation pit, including pit depth distribution, slope change and surface roughness, etc., and at the same time collect the local hydrological and meteorological data to obtain the basic data of tidal current, wave and ocean current. The tidal current data includes the maximum flow velocity, flow direction and tidal cycle; the wave data includes the significant wave height, wave period and wave direction; the ocean current data includes the flow velocity, flow direction and vertical distribution characteristics. Combine these hydrological parameters with the three-dimensional terrain data of the sand excavation pit, and use hydrodynamic numerical simulation technology to construct a hydrodynamic model of the seabed sand excavation pit area. During the simulation calculation, the sand excavation pit area is discretized into a large number of grid cells, and the hydrodynamic control equations are applied to each cell, and the flow field and wave field distributions of the entire area are obtained by solving. The calculation results are expressed as parameters such as the flow velocity, flow direction, wave height and wave direction of each grid point under different filling stages. By comparing the changes in hydrodynamic parameters before and after filling, evaluate the impact degree of filling on the hydrodynamic environment, and form the hydrodynamic impact evaluation result.

[0051] Based on the hydrodynamic impact evaluation result, further calculate and analyze the sediment migration law. First, determine the starting condition of the sediment, that is, when the water flow force exceeds the critical starting force of the sediment, the critical state when the sediment begins to move. For sediments with different particle sizes and densities, their critical starting flow velocities are different. Combine the physical characteristic parameters of the repair material (such as particle size, density, cohesion, etc.) with the hydrodynamic simulation results, and calculate the starting probability and transport intensity of the filling material in each area under the action of water flow. For areas with a high starting probability, the filling material is easily scoured by the water flow, and the stability parameters need to be improved; for areas with a large transport intensity, secondary erosion is likely to occur after filling, and protective measures need to be strengthened. By comprehensively considering the hydrodynamic conditions and sediment characteristics, determine the stability parameters of the filling material in each area, including the minimum particle size requirement, minimum density requirement and structural strength requirement, etc., and form the filling area zoning plan.

[0052] According to the filling area zoning plan, the sand mining pit is divided into multiple filling units. The division principle is based on the similarity of the bottom depth, slope change and hydrodynamic conditions. The area of each filling unit is controlled within 5000 square meters to ensure the controllability of the filling process. Detailed engineering parameters are formulated for each filling unit, including the filling thickness (determined according to the difference between the target restoration elevation and the current elevation), the material ratio (adjusting the proportion of aggregate, curing agent and fiber material according to the stability parameter requirements of this area), and the construction time (considering the curing time of the material and the connection sequence of adjacent units). The filling thickness is larger in the bottom area of the pit and gradually decreases in the pit wall area, forming a smoothly transitional terrain. The material ratio increases the proportion of aggregate and curing agent in the area with strong hydrodynamic action to improve the anti-scouring ability. The construction time arrangement follows the principle of "from deep to shallow, from inside to outside", and considers the tidal cycle and seasonal meteorological conditions, avoiding adverse construction periods such as storm surges.

[0053] When optimizing the project implementation plan, key considerations include the connection method between filling units and the settlement reservation problem. The stepped filling method is adopted for the connection between units, and the height difference between adjacent units is controlled within 0.5 meters, forming a gentle slope transition to avoid local scouring caused by terrain drops. At the same time, consider the consolidation settlement effect under the action of the self-weight of the filling material and seawater immersion. By analyzing the compression index and consolidation coefficient of the filling material, the expected settlement amount is calculated. Generally, the reserved settlement space is 1.1 - 1.2 times the expected final settlement amount, usually 10 - 15% of the total filling thickness. The optimized filling plan also considers the treatment of boundary conditions. A smooth transition section is designed at the junction of the sand mining pit and the surrounding natural seabed, with a slope not exceeding 1:10, to prevent the formation of new terrain fractures.

[0054] According to the spatial relationship between the storage location of the repair materials and the sand mining pit, the best transportation route is designed. Consideration factors include transportation distance, water depth conditions, waterway conditions and avoiding sensitive areas, etc. When the transportation distance exceeds 10 kilometers, the combined method of barge transportation and pipeline transportation is more economical and efficient. The barge design should consider the load capacity, navigation stability and positioning accuracy. The load capacity is determined according to the single filling volume and round-trip time. Generally, a flat-bottom barge with a load capacity of 200 - 500 cubic meters is selected; the navigation stability requires that the hull can withstand certain wind and wave conditions; the positioning accuracy is achieved by equipping with a GPS positioning system and a dynamic positioning system, and the positioning accuracy reaches ±1 meter. After the barge arrives at the designated filling position, it needs to be accurately positioned and anchored stably to prevent drifting during the unloading process.

[0055] When designing a conveying pipeline system based on a maritime transportation plan, key parameters need to be determined, including pipe diameter, flow velocity, conveying pressure, and diffuser parameters. The pipe diameter is selected based on the conveying volume and distance, and generally, pipes with a diameter of 300 - 500 mm are used. The flow velocity is controlled at 2 - 3 m / s to avoid pipe wear and prevent sediment blockage at low flow velocities. The conveying pressure is calculated based on the elevation difference, conveying distance, and material properties. Generally, a high-pressure conveying pump needs to be equipped, and the pressure reaches 0.8 - 1.2 MPa. The pipe material is selected as a wear-resistant and corrosion-resistant composite material. The pipeline laying takes into account the stability under the action of waves and water flow, and regular inspections and maintenance are carried out to prevent leakage. The diffuser design is the key to ensuring the uniform distribution of the filling material. The release speed and diffusion range are controlled through multiple outlets, and the number and diameter of the outlets are determined according to the filling unit area.

[0056] In a specific embodiment, the process of executing step S103 may specifically include the following steps:

[0057] Use the transportation system to direct the repair material of the mixed aggregate to the deepest part of the sand excavation pit to form the bottom filling material. The filling thickness is controlled according to the depth gradient of the sand excavation pit to obtain the bottom filling body.

[0058] Vibrate the bottom filling body using underwater vibration compaction equipment. The vibration frequency and amplitude are adjusted according to the density of the filling material, and the surface after compaction is leveled to obtain a dense bottom foundation.

[0059] Transport the repair material mixed with the curing agent to above the bottom foundation in sections by the transportation system to form the middle filling body. A specific gradient change is maintained between the middle filling body and the bottom foundation to obtain a stepped filling structure.

[0060] Perform underwater grouting treatment on the stepped filling structure. The grouting points are arranged in a grid pattern. The grouting pressure and time are determined according to the size of the filling area and material properties to obtain a middle layer solidified body with a firmly connected interior.

[0061] Transport the improved dredged mud and fine sand mixture to the surface of the middle layer solidified body, control the surface layer thickness and surface flatness, and perform grid anchoring treatment on the area in contact with the pit wall to obtain a filling structure anchored and connected to the pit wall.

[0062] Specifically, using the transportation system to direct the repair material of the mixed aggregate to the deepest part of the sand excavation pit is the first step of bottom filling. The directed placement technology refers to the technology of accurately placing specific materials at the predetermined position by precisely controlling the placement position and placement method. In actual operation, after the barge arrives at the designated filling area, the precise position is determined through the GPS positioning system and the underwater acoustic positioning system. The end of the placement pipe keeps an appropriate distance from the seabed, generally 3 - 5 meters, to avoid material dispersion caused by too far distance or seabed disturbance caused by too close distance. The bottom filling material is a mixture of dredged mud and aggregate. The aggregate is mainly gravel with a particle size of 5 - 20 mm, and the mixing ratio is the mass ratio of dredged mud to aggregate of 7:3. The filling thickness is controlled according to the depth gradient of the sand excavation pit. The filling thickness is larger at the deepest part of the pit bottom, generally 1.5 - 2.5 meters, and gradually decreases towards the pit wall, forming a filling body that smoothly transitions with the natural terrain. During the filling process, the filling height is monitored in real time through an echo sounder, and the placement is stopped when the designed thickness is reached, controlling the filling accuracy within ±10 cm. The underwater vibration compaction equipment is a mechanical equipment dedicated to compacting underwater loose materials, mainly composed of a vibration source, a ram plate, and a control system. The mechanical vibration generated by the vibration source is transmitted to the filling body through the ram plate, causing the particles of the filling material to rearrange, reducing the porosity, and increasing the density. The vibration frequency and amplitude are two key parameters that need to be adjusted according to the density of the filling material. For filling materials with a larger density (such as mixtures with a high proportion of aggregate), the vibration frequency is set lower, generally 20 - 30 Hz, and the amplitude is larger, 5 - 8 mm; for filling materials with a smaller density, the vibration frequency is set higher, 30 - 40 Hz, and the amplitude is smaller, 3 - 5 mm. The compaction process is carried out along a grid-like route, with a grid spacing of 1.5 - 2 meters, ensuring that the entire filling area is covered. The vibration time at each point is 30 - 60 seconds. After compaction, the underwater leveling equipment is used to level the surface, eliminating local protrusions and depressions, and controlling the surface height difference within ±5 cm, forming a uniform and flat bottom foundation.

[0063] Transporting the repair material mixed with the curing agent to above the underlying foundation in zones and sections through the transportation system is the main process of the middle layer filling. The middle layer filling material is a mixture of dredged mud and the curing agent. The curing agent is mainly composed of cement, fly ash, and reactive lime, with a mixing ratio of 3:5:2, and the mixing ratio with the dredged mud is dredged mud:curing agent = 9:1 (mass ratio). The middle layer filling is carried out in a zonal and sectional manner. The entire filling area is divided into several filling units, and the area of each unit is approximately 500 - 1000 square meters. The purpose of zonal filling is to control the filling volume each time, ensure uniform distribution of the material, and have sufficient time for curing. The filling thickness is controlled within 0.8 - 1.2 meters, and the height difference between adjacent filling areas does not exceed 0.5 meters, forming a stepped filling structure. The design purpose of the stepped structure is to increase the interlayer contact area, improve the interlayer bonding strength, and prevent interlayer slip. A specific gradient change is maintained between the middle layer filling body and the underlying foundation, that is, the middle layer edge gradually thins, forming a wedge-shaped transition zone with the bottom layer to enhance the overall stability.

[0064] Underwater grouting treatment of the stepped filling structure is an important measure to improve the internal strength of the filling body. Underwater grouting refers to the technology of injecting a specific slurry into the underwater structure through grouting equipment to fill the pores and improve the overall strength and impermeability. The grouting points are arranged in a grid pattern with a grid spacing of 2 - 3 meters, covering the entire middle - layer filling body. The grouting slurry is composed of ultra - fine cement, water glass, and retarder. The particle size of the ultra - fine cement is less than 20 microns, which has good fluidity and permeability; water glass is used as an early - strength agent to accelerate the setting of the slurry; the retarder controls the setting time to ensure that the slurry can fully penetrate into the filling body. The grouting pressure is controlled at 0.2 - 0.3 MPa. Excessive pressure will cause damage to the filling body, while too low pressure will not allow the slurry to fully penetrate. The grouting time is determined according to the size of the filling area and material properties, generally 15 - 30 minutes for each grouting point until the slurry overflows from adjacent grouting points, indicating that the area is completely saturated. Through grouting treatment, a grid - shaped reinforcement system is formed, significantly improving the overall strength and erosion resistance of the middle - layer filling body. Transporting the improved dredged mud and fine - sand mixture to the surface of the middle - layer solidified body is the key process of surface filling. The surface - filling material is specially improved dredged mud, adding 10 - 15% fine sand (particle size 0.1 - 2 mm), 5 - 8% shell debris, and 3 - 5% organic matter (such as seaweed residues) to simulate the natural seabed sediment environment. The surface material is transported in a low - pressure and low - disturbance manner to prevent damage to the underlying structure. The surface thickness is controlled at 0.5 - 0.8 meters, and the thickness uniformity is controlled within ±5 cm. After the surface filling is completed, an underwater leveling device is used to finely level the surface to ensure that the surface is flush with or slightly lower than the surrounding natural seabed by 5 - 10 cm, reserving space for subsequent natural sedimentation. For the area in contact with the pit wall, the grille anchoring technology is used for treatment. Grille anchoring refers to the technology of installing stainless - steel grille anchorages on the pit wall to firmly connect the filling body to the pit wall. The spacing of the anchorages is 3 - 5 meters, penetrating 0.5 - 1 meter into the pit wall, forming an anchoring connection with the filling body to prevent the filling body from separating from the pit wall and enhancing the overall stability.

[0065] In a specific embodiment, the process of executing step S104 may specifically include the following steps:

[0066] According to the surface characteristics and hydrodynamic conditions of the filling structure, a mixture of fine - sand and clay with a fine particle size is prepared as the transition - layer material, and the transition - layer material is laid on the surface of the filling structure to obtain a transition protection layer;

[0067] Judge whether the transition protection layer meets the bottom - layer connection requirements. If it meets, gravel and cementing material are mixed to cover the transition protection layer to form a middle - layer protection layer, obtaining a stable structure;

[0068] Judge the erosion resistance performance of the middle protective layer. If the erosion resistance performance index is lower than the set threshold, increase the proportion of the cementitious material for reinforcement treatment; if the erosion resistance performance index is higher than the threshold, select natural materials to cover the middle protective layer to obtain a three-layer protective structure;

[0069] Conduct a water flow action analysis on the filling structure, calculate the water flow velocity and erosion intensity in each area. When the erosion intensity exceeds the bearing capacity of the protective layer, it is determined as a high erosion risk area to obtain a distribution map of the protective reinforcement area;

[0070] Judge the position and scope of the protective reinforcement area. When it is located at the pit edge and the water flow concentration area, lay a gabion cage structure, bury the cage edge into the bottom layer, and connect the cages through connecting lines to obtain an erosion-resistant structure;

[0071] Judge the water flow velocity around the erosion-resistant structure. When the velocity exceeds the critical value, set up an energy dissipation device composed of riprap or concrete blocks to divert and reduce the energy of the incoming water flow to obtain an erosion-resistant surface system.

[0072] Specifically, when formulating the transition layer material according to the surface characteristics and hydrodynamic conditions of the filling structure, it is first necessary to analyze the physical characteristics of the filling structure surface and the hydrodynamic conditions of the water area where it is located. The surface characteristics include particle size composition, surface roughness, permeability, etc., which are obtained through on-site sampling analysis; the hydrodynamic conditions include wave height, flow velocity, flow direction, tidal cycle, etc., which are obtained through hydrological observations. According to these data, formulate a suitable transition layer material, which is mainly composed of fine sand with a particle size of 0.1 - 0.5 mm and clay mixed in a mass ratio of 7:3. The fine sand provides a skeleton support effect, and the clay fills the particle gaps and provides cohesion. The moisture content of the prepared mixture is controlled at 25 - 30% to ensure that the material has appropriate fluidity and plasticity. Lay this mixture evenly on the surface of the filling structure through a conveying pipeline with a thickness of 0.2 - 0.3 m, ensure that there is no blank area on the coverage surface, and control the thickness error within ±2 cm to form a transition protective layer.

[0073] The judgment criteria include three aspects: bonding strength, permeability, and uniformity. Cylindrical samples with a diameter of 10 cm are taken at different positions by the core sampling method for indoor bonding strength testing to determine the interfacial bonding strength between the transition protective layer and the underlying filling structure; the permeability coefficient of the transition protective layer is determined through in-situ permeability tests; the uniformity of the thickness distribution of the transition layer is detected by ultrasonic scanning technology. When the bonding strength reaches the design value (generally 30 - 50 kPa), the permeability coefficient is not greater than 1×10^-5 cm / s, and the thickness uniformity is good (coefficient of variation less than 15%), it is determined that the transition protective layer meets the requirements for bottom layer connection. After meeting the requirements, the middle protective layer material is prepared by mixing gravel with a particle size of 5 - 20 mm and a cementing material (such as modified asphalt, epoxy resin, etc.) in a mass ratio of 8:2. The cementing material plays a role in bonding the gravel particles and preventing the loss of fine particles. The mixed material is evenly covered on the transition protective layer with a thickness of 0.3 - 0.5 m to form the middle protective layer, obtaining a preliminary stable structure.

[0074] The anti-scour performance refers to the ability of the protective structure to resist material loss under the action of water flow, which is expressed by the anti-scour performance index. The anti-scour performance index is obtained through a flume scour test. The specific method is to simulate the in-situ water flow conditions (flow velocity, water depth, waves, etc.) in a laboratory flume, conduct timed scouring on the protective layer material sample, measure the material loss per unit time, calculate the loss rate, and then determine the anti-scour performance index according to the ratio of the loss rate to the critical loss rate. The critical loss rate is the maximum allowable material loss rate during the design service life, usually determined according to the engineering design standards. When the anti-scour performance index is lower than the set threshold (usually 1.2), it indicates that the anti-scour ability of the protective layer is insufficient, and it is necessary to increase the proportion of the cementing material for reinforcement treatment. The reinforcement treatment is achieved by increasing the proportion of the cementing material to 25 - 30%, or replacing it with a high-strength cementing material. If the anti-scour performance index is higher than the threshold, natural materials similar to the surrounding seabed environment (such as sandy, gravelly, or shell debris on the local seabed) are selected to cover the middle protective layer with a thickness of 0.3 - 0.4 m to form the surface protective layer, enabling the repaired area to naturally transition to the surrounding seabed environment and completing the construction of the three-layer protective structure.

[0075] The analysis of the water flow effect on the filling structure is the basis for identifying high-scour-risk areas. The water flow effect analysis obtains data through two methods: one is on-site observation, using an Acoustic Doppler Current Profiler (ADCP) to measure the water flow field around the filling area under different tidal levels and seasonal conditions to obtain parameters such as flow velocity and flow direction; the other is numerical simulation, based on a three-dimensional Computational Fluid Dynamics (CFD) model, inputting the topographic data after the sand mining pit is filled and the local hydrological conditions into the model to simulate the water flow distribution under different working conditions. By analyzing and processing these data, the water flow velocity and scour intensity of each area are calculated. The scour intensity calculation considers the comprehensive influence of water flow velocity, bottom shear stress, wave action, and topographic factors. When the calculated scour intensity exceeds the bearing capacity of the protective layer (i.e., the critical incipient stress of the material), this area is determined as a high-scour-risk area. All high-scour-risk areas are marked on the plan of the filling area to form a distribution map of the areas requiring enhanced protection, providing spatial guidance for subsequent enhanced protection measures.

[0076] Judging the location and scope of the areas requiring enhanced protection is the basis for determining the layout of the gabion cage structure. By analyzing the distribution map of the areas requiring enhanced protection and combining the topographic features and hydrodynamic conditions, the location characteristics of each high-scour-risk area are judged. When the high-scour-risk area is located at the pit edge (i.e., the transition zone between the sand mining pit and the natural seabed) or in areas with concentrated water flow (such as topographic depressions, water flow convergence channels, etc.), the gabion cage structure is used for protection. A gabion cage is a wire mesh box woven from high-strength steel wires or synthetic materials, filled with stones inside to form an integral structure, with high scour resistance and flexibility. The size of the gabion cage is usually 1 m × 1 m × 0.5 m, the mesh size is 6 cm × 8 cm, and hard stones with a particle size of 50 - 100 mm are filled. When laying, it is arranged according to the shape of the risk area, and the cages are firmly connected by connecting wires to form an overall protective net. At the contact with the bottom layer, the edge of the cage is buried at least 0.5 m deep into the bottom layer to prevent the water flow from scouring downward and causing the structure to become unstable. After laying, an underwater inspection is carried out to ensure that there is no deformation, disconnection, or filler loss in the cage structure, forming an effective anti-scour structure.

[0077] Judging the water flow velocity around the anti-erosion structure is the basis for determining whether an energy dissipation device needs to be set up. Based on the data obtained from the foregoing water flow action analysis, the water flow velocity distribution information in the area around the anti-erosion structure is extracted. According to the design code for hydraulic protection structures, the critical velocity value under the local environment is determined. The critical velocity refers to the minimum velocity at which obvious erosion begins to occur around the anti-erosion structure under the action of this velocity, and it is usually determined through engineering experience and test data. When the actual velocity exceeds the critical value, an energy dissipation device needs to be set up to control the velocity. The energy dissipation device mainly includes two forms: one is the rockfill structure, which is formed by piling up irregularly shaped stones, and the particle size of the stones is generally 200-500 mm, and the stacking height is 0.6-1.0 m; the other is the concrete block, which is a standardized concrete component, such as energy dissipation blocks in the shape of hexagons, quadrangular pyramids, etc., and the weight of a single block is 50-200 kg. The energy dissipation device is set on the upstream side in the direction of the incoming flow. By changing the water flow path, generating eddies and frictional losses, the purpose of reducing the water flow energy and lowering the velocity is achieved. The layout of the energy dissipation device should consider the water flow direction, intensity and variation law to form a protection system that matches the water flow characteristics. Through careful design and fine construction, a complete anti-erosion surface system is finally formed to effectively protect the filling structure from water flow scouring and erosion.

[0078] In a specific embodiment, the process of performing the step of constructing the three-layer protection structure may specifically include the following steps:

[0079] Take a sample of the middle-layer protection layer for anti-erosion test, measure the loss amount per unit time of the protection layer material under water flow scouring, calculate the material loss rate, and obtain the basic anti-erosion data;

[0080] Compare and analyze the basic anti-erosion data with the results of the hydrodynamic impact evaluation, calculate the anti-erosion performance index of the middle-layer protection layer in different regions, and obtain the anti-erosion performance distribution map;

[0081] Determine the anti-erosion performance threshold according to the material mechanical properties and engineering experience values, compare the anti-erosion performance index with the threshold, mark the regions where the index is lower than the threshold, and obtain the distribution of the reinforcement regions;

[0082] Increase the proportion of the cementitious material in the middle-layer protection layer of the reinforcement region, determine the addition amount of the cementitious material according to the difference between the anti-erosion performance index and the threshold in different regions, and supplement and add the cementitious material to obtain the reinforced middle-layer protection layer;

[0083] Select natural materials that match the surrounding seabed environment as the surface layer material, determine the particle size and thickness of the surface layer material according to the water depth, wave conditions and seabed type, form a design scheme for the surface layer protection layer, and obtain the surface layer formula;

[0084] Evenly cover the surface of the middle protective layer with the materials of the surface layer formula, and control the covering thickness and flatness to make the surface smoothly transition to the seabed elevation around, thus obtaining a three-layer protective structure.

[0085] Specifically, sampling the middle protective layer for the anti-scour test is the first step to obtain the basic anti-scour data. The specific operation is to take multiple representative samples from the laid middle protective layer. The sample size is usually 30 cm × 30 cm × the actual thickness of the protective layer. The sampling positions should cover different water depth areas and terrain feature areas to ensure the representativeness of the samples. The taken samples are sent into a special flume scouring test device, which can simulate the hydrodynamic conditions of the actual sea area, including parameters such as flow velocity, wave and water depth. The test conditions are set as the extreme hydrodynamic conditions of the local sea area, such as the maximum flow velocity and wave height once in a hundred years. Under the set conditions, conduct a continuous 72-hour scouring test on the samples, take out the samples to weigh every 6 hours, and record the change of the sample weight over time. By calculating the weight loss of the samples per unit time, the material loss rate is obtained, with the unit of kg / m² / day. This data directly reflects the anti-scour ability of the protective layer material under the action of water flow. The lower the loss rate, the stronger the anti-scour ability.

[0086] Comparing the anti-scour foundation data with the results of hydrodynamic impact assessment is a necessary step in evaluating the performance of the protective layer under actual use conditions. The results of hydrodynamic impact assessment include parameters such as water flow velocity, wave height, and wave period at each point in the restoration area. By comparing these parameters with the anti-scour test conditions, a relationship function of material loss rate under different hydrodynamic conditions can be established. The specific operation is to spatially match the location information of the sampling points with the grid points in the hydrodynamic impact assessment to establish a set of hydrodynamic parameters for each sample point, and then obtain the hydrodynamic distribution of the entire restoration area through interpolation. The material loss rate of each sample is correlated with the hydrodynamic parameters at the corresponding location to establish a functional relationship between the loss rate and the hydrodynamic parameters. Based on this relationship and combined with the hydrodynamic distribution of the entire restoration area, the anti-scour performance index of the middle protective layer in different areas is calculated. The anti-scour performance index is defined as the ratio of the critical loss rate of the protective layer material to the predicted loss rate, and the critical loss rate refers to the maximum material loss rate allowed within the design service life. The calculated anti-scour performance index is plotted on the plan of the restoration area in the form of contour lines to form an intuitive anti-scour performance distribution map, clearly showing the anti-scour performance status of each area. Determining the anti-scour performance threshold based on the material mechanical properties and engineering experience values is the basis for judging whether the protective layer needs to be reinforced. The anti-scour performance threshold is determined by comprehensively considering multiple factors, including the physical and mechanical properties of the protective material (such as particle size, density, cohesion, etc.), design service life, engineering safety level, and accumulated engineering experience values. For general marine engineering, the anti-scour performance threshold is usually set at 1.2 - 1.5, that is, the predicted loss rate should not be greater than 67% - 83% of the critical loss rate, providing sufficient safety redundancy for the system. The anti-scour performance index calculated for each area is compared with the set threshold. When the index is lower than the threshold, the area is marked as an area that needs to be reinforced. All areas that need to be reinforced are marked on the plan of the restoration area to form a reinforcement area distribution map, which is used to guide subsequent reinforcement work. This method based on the comparison of performance index and threshold can accurately identify weak links and implement targeted reinforcement measures, ensuring both the protection effect and saving engineering costs.

[0087] Increasing the proportion of the cementitious material in the middle protective layer of the reinforced area is an effective means to improve the anti-scouring performance. The cementitious material refers to the material that can bond loose particles into an integral structure, such as epoxy resin, modified asphalt, cement-based materials, etc. The specific operation of increasing the proportion of the cementitious material is to determine the supplementary addition amount of the cementitious material according to the difference between the anti-scouring performance index and the threshold value in different areas. The larger the difference, the higher the proportion of the cementitious material to be added. The calculation formula is: Supplementary addition ratio = Basic addition ratio × (Threshold value / Index - 1) × Adjustment coefficient, where the basic addition ratio is the proportion of the cementitious material in the initial design, generally 15% - 20%; the adjustment coefficient is a parameter determined according to the type of the cementitious material and environmental conditions, generally 1.1 - 1.3. After calculating the proportion of the cementitious material to be supplemented in each area, the supplementary addition is carried out according to the area division. The supplementary addition adopts the surface perfusion method. First, the liquid cementitious material is evenly sprayed on the surface of the protective layer, and the self-weight and pressure are used to assist the penetration of the cementitious material into the interior of the protective layer. After the cementitious material is cured, an integral structure is formed. After reinforcement, the protective layer is sampled and tested to confirm that the anti-scouring performance index has been increased above the threshold value, and the reinforced middle protective layer is formed. Selecting natural materials matching the surrounding seabed environment as the surface layer material is an important measure to achieve seamless connection between the repaired area and the natural seabed. The selection of the surface layer material should be based on a detailed investigation of the surrounding seabed environment, including the bottom sediment type, grain size composition, mineral composition, etc. Through multi-point sampling and laboratory analysis, the bottom sediment characteristic data of the surrounding seabed are obtained. At the same time, the influence of water depth, wave conditions and seabed type on the surface layer material is considered. The water depth affects the light intensity and water pressure, and thus affects the stability of the material; the wave conditions determine the anti-scouring ability required by the material; the seabed type determines the physical and chemical properties that the surface layer material should possess. Considering these factors comprehensively, the particle size range and thickness of the surface layer material are determined. Generally speaking, the particle size should be close to or slightly larger than the particle size of the natural sediment on the surrounding seabed to provide sufficient stability; the thickness is determined according to the wave conditions and water depth, generally 0.3 - 0.6 meters. According to the above parameters, a surface layer protection layer design scheme is formed, including material composition, particle size range, thickness distribution, etc., and finally a specific surface layer formula is obtained.

[0088] Before covering, the surface of the middle protective layer is cleaned to remove loose objects and impurities to ensure good adhesion between the surface layer and the middle layer. The covering method adopts the partition and layer laying method, dividing the entire repair area into several construction units, and each unit evenly lays the surface material according to the designed thickness. During the laying process, the thickness is measured in real time to ensure that the covering thickness meets the design requirements and the thickness error is controlled within ±5 cm. After the covering is completed, the surface is finely leveled using underwater leveling equipment to ensure that the surface flatness meets the design requirements. Special attention is paid to the transition area between the repair area and the surrounding natural seabed. A gradual thickness design is adopted to make a smooth transition between the surface of the repair area and the surrounding seabed elevation. The width of the transition zone is generally 5-10 meters, and the slope is not greater than 1:10, to avoid the formation of obvious terrain drop and prevent water disturbance and scouring caused by local terrain changes. Through this series of fine operations, a three-layer protective structure with complete structure and coordinated functions is finally formed, providing long-term and stable protection for the filling body.

[0089] In a specific embodiment, the process of executing step S105 may specifically include the following steps:

[0090] Install settlement monitoring points, water flow monitoring equipment and pore pressure sensors at key locations of the anti-erosion surface system to collect settlement data, water flow parameters and pore water pressure data to obtain raw monitoring data;

[0091] Process the raw monitoring data, remove abnormal values, calculate the sedimentation rate, water flow velocity change and pressure change trend, and obtain the processed monitoring data;

[0092] Compare the processed monitoring data with the design standard value to determine whether the settlement of the filling body exceeds the reserved settlement amount and whether the pore water pressure reaches a stable state, and obtain the stability determination result;

[0093] Underwater sonar scanning of the anti-erosion surface system measures changes in surface morphology, calculates erosion depth and range, determines the integrity of the protective structure, and obtains an anti-erosion effect evaluation;

[0094] According to the stability determination results and anti-erosion effect evaluation, the repair area is graded and assessed, and the areas that need to be reinforced or strengthened are marked to obtain subsequent maintenance area identification;

[0095] The monitoring data, stability determination results, anti-erosion effect evaluation and subsequent maintenance area identification are integrated and stored, and an information system containing time series data and spatial distribution data is established to obtain a restoration effect evaluation database.

[0096] Specifically, installing monitoring equipment at key locations of the anti-erosion surface system is the basis for obtaining engineering status data. The selection of key locations is based on the topographic characteristics and hydrodynamic conditions of the filling area, usually including the center point of the filling area, the edge transition zone, the area with large terrain drop, and the water flow concentration area. The settlement monitoring point is a special device for measuring the vertical displacement of the filling body. It consists of a settlement plate, a measuring pole and a signal transmission device. It is installed at different depths inside the filling body or on the surface. Generally, 1-2 are arranged per 1,000 square meters, and the number is appropriately increased in areas where the filling thickness changes significantly. The water flow monitoring equipment is mainly an acoustic Doppler current profiler (ADCP), which measures the water flow velocity and direction through the ultrasonic Doppler effect. It is installed in areas with strong water flow. The measurement range covers all layers of the water body. The collection frequency is once an hour, and the parameters such as water flow velocity, flow direction and wave height are recorded. The pore pressure sensor is an instrument for measuring the pore water pressure inside the filling body. It is buried at different depths of the filling body. Each settlement monitoring point corresponds to 2-3 pore pressure sensors to form a vertical measurement profile. The collection frequency is once an hour. The data collected by these monitoring devices are transmitted to the data receiving terminal in real time through the underwater communication system, forming an original data set containing time, location, and measurement values. Processing the raw monitoring data is a necessary step in analyzing the performance of the filling body. First, data cleaning is performed to eliminate outliers. The 3σ rule is used to determine outliers, that is, data points that deviate from the mean value ±3 times the standard deviation are considered abnormal and eliminated. For settlement data, the settlement curve of each monitoring point over time is calculated, and the settlement rate is calculated using the difference method in millimeters per day. The settlement rate calculation formula is: settlement rate = (current settlement - previous settlement) / (current time - previous time). For water flow data, the mean, maximum and direction change characteristics of the flow velocity at different water depths of each monitoring point are calculated, and the flow velocity change trend and extreme value occurrence time within the tidal cycle are analyzed. For pore water pressure data, the pressure change trend with time and depth is calculated, and the drainage during the consolidation process is analyzed. By processing these data, key indicator values that can reflect the engineering status of the filling body are obtained to form a processed monitoring data set. Comparing the processed monitoring data with the design standard value is an important part of judging the status of the project. The design standard value is the allowable range of various indicators determined according to theoretical calculations and empirical values during the engineering design stage, including reserved settlement, maximum allowable settlement rate, pore water pressure dissipation rate, etc. The comparison process first checks whether the settlement of the filling body exceeds the reserved settlement. The reserved settlement is usually 10-15% of the total thickness of the filling. Compare the measured maximum settlement with the reserved settlement. When the measured value is less than 80% of the reserved value, it is judged to be in the safe range; when the measured value reaches 80%-100% of the reserved value, it is judged to be in the warning range; when the measured value exceeds the reserved value, it is judged to be in the over-standard range.Secondly, analyze the changing trend of the settlement rate. Under normal circumstances, the settlement rate should gradually decrease over time and tend to be stable. When the settlement rates measured three times in a row are all less than the set threshold (usually 0.5 mm / day), it is determined that the settlement has entered the stable stage. Thirdly, analyze the pore water pressure data and calculate the pressure dissipation rate, which is the ratio of the decrease in pore water pressure to the initial excess hydrostatic pressure. When the pressure dissipation rate reaches over 90% and the pressure value tends to be stable, it is determined that the consolidation process is basically completed. Through these comparative analyses, the comprehensive determination result of the stability of the filling body is obtained.

[0097] Underwater sonar scanning of the anti-erosion surface system is a direct means to evaluate the integrity of the protective structure. Underwater sonar scanning uses a multi-beam bathymetric system or a side-scan sonar system to conduct full-coverage scanning of the repair area to obtain high-precision terrain data. The scanning is carried out along equally spaced survey lines, and the line spacing is no more than twice the water depth to ensure that the data overlap rate reaches over 50% and the scanning resolution reaches 10 cm or higher. Compare the terrain data obtained from the scanning with the reference terrain data at the completion of the repair, calculate the change in surface elevation, and draw an isogram of the change amount to visually display the eroded or silted areas. The erosion depth refers to the vertical distance by which the surface has dropped and is calculated by the difference between the current elevation and the reference elevation; the erosion range refers to the area where the erosion depth exceeds the set threshold (generally 5 cm). Based on the distribution characteristics of the erosion depth and range, judge the integrity status of the protective structure. When the maximum erosion depth is less than 20% of the designed protective layer thickness and the erosion range accounts for no more than 10% of the total area, it is judged to be in good condition; when the maximum erosion depth reaches 20%-50% of the designed protective layer thickness, or the erosion range accounts for 10%-30% of the total area, it is judged to be in a state that requires attention; when the maximum erosion depth exceeds 50% of the designed protective layer thickness, or the erosion range accounts for more than 30% of the total area, it is judged to be in a state that requires repair. Through this quantitative evaluation method, objectively evaluate the anti-erosion effect. Based on the stability determination result and the anti-erosion effect evaluation, grading the repair area is an important step in guiding later maintenance. The grading uses the matrix method, combining the stability determination and the anti-erosion evaluation results to form a comprehensive rating matrix. The stability determination result is divided into three levels: stable, basically stable, and unstable; the anti-erosion effect evaluation is divided into three levels: good, requiring attention, and requiring repair. The combination of the two forms nine states, which are further simplified into five levels: excellent, good, average, poor, and very poor. Areas in the excellent level do not require maintenance measures; areas in the good level require regular observation; areas in the average level require increased monitoring frequency and formulation of preventive maintenance plans; areas in the poor level require timely local reinforcement or strengthening; areas in the very poor level require immediate implementation of comprehensive repair. On the plan of the repair area, mark each level area with different colors to form an intuitive identification map of the subsequent maintenance area to guide the priority order and resource allocation of the maintenance work.

[0098] Integrating and storing monitoring data, stability determination results, anti-erosion effect evaluation, and subsequent maintenance area identification to establish a repair effect evaluation database is the guarantee for long-term scientific management. The database is designed with a hierarchical structure, including four levels: the original data layer, the processed data layer, the evaluation result layer, and the decision support layer. The original data layer stores the original data collected by monitoring devices, including information such as timestamps, device IDs, and measurement values; the processed data layer stores various index values after data processing, such as settlement rates and pressure dissipation rates; the evaluation result layer stores the stability determination results and anti-erosion effect evaluation results; the decision support layer stores the grading evaluation results and maintenance suggestions. The database supports two data organization methods: time series data organization, which stores the parameter change processes of each monitoring point in chronological order for trend analysis; spatial distribution data organization, which stores the state parameters of each area according to spatial positions for spatial analysis. The database provides query, statistics, analysis, and visualization functions, supports multi-dimensional data display and warning functions, and automatically triggers warnings and pushes relevant information when monitoring parameters exceed preset thresholds. Through this systematic data management, scientific monitoring and management of the entire life cycle of the repair project are achieved.

[0099] The above describes the method for controlling the repair of submarine sand mining pits based on marine dredged mud in the embodiments of the present application. Next, the control system for repairing submarine sand mining pits based on marine dredged mud in the embodiments of the present application will be described. Please refer to Figure 2 , an embodiment of the control system for repairing submarine sand mining pits based on marine dredged mud in the embodiments of the present application includes:

[0100] A collection module 201, configured to perform topographic mapping and environmental sample collection and analysis on the submarine sand mining pit to obtain three-dimensional topographic data of the sand mining pit, and perform improvement treatment on the marine dredged mud to obtain repair materials;

[0101] An analysis module 202, configured to analyze the filling scheme based on the three-dimensional topographic data and the repair materials, generate a target filling scheme, and construct a transportation system combining barge transportation and pipeline transportation;

[0102] A filling module 203, configured to fill the repair materials into the sand mining pit in layers of bottom, middle, and surface based on the transportation system, and perform vibration compaction and underwater grouting treatment on each layer of filling body to obtain a filling structure;

[0103] A construction module 204, configured to construct a three-layer protection structure on the surface of the filling structure, and add gabion cages and energy dissipation structures in high-scour-risk areas to obtain an anti-erosion surface system;

[0104] An evaluation module 205, configured to evaluate the repair effect of the anti-erosion surface system according to a preset monitoring network to obtain a repair effect evaluation database.

[0105] Through the collaborative cooperation of the above-mentioned various components, the steps of topographic surveying and environmental sample collection and analysis of the seabed sand mining pit have constructed a comprehensive and accurate three-dimensional topographic model and environmental assessment system, providing an accurate data basis for subsequent restoration. At the same time, targeted improvement treatment is carried out on marine dredged mud, realizing the resource utilization of dredged mud and solving the problem of dredged mud disposal; based on the three-dimensional topographic data and restoration materials, the filling scheme is analyzed, and artificial intelligence algorithms are applied to simulate and predict the hydrodynamic conditions and sediment migration laws, generating a target filling scheme for the specific environment, and constructing a precisely positioned transportation system, greatly improving the construction accuracy and efficiency; the layered filling technology is combined with vibration compaction and underwater grouting treatment to form a filling body with stable structure, enhancing the overall bearing capacity and anti-deformation ability; the three-layer protection structure design is combined with the application of gabion cages and energy dissipation structures in high-risk areas to construct an all-round anti-erosion surface system, significantly improving the anti-scouring ability and long-term stability of the restoration area under extreme hydrodynamic conditions; the pre-set monitoring network is combined with data processing algorithms to realize the scientific evaluation and dynamic management of the restoration effect. Through the intelligent processing of a large amount of spatial data, the accurate analysis and prediction of the complex seabed environment are realized, improving the pertinence and scientificity of the scheme. In the anti-scouring performance evaluation, a correlation model between hydrodynamic parameters and material properties is established, realizing the precise matching of protection requirements in different regions, and an anomaly detection algorithm is applied in the monitoring data processing to improve the data quality and early warning accuracy.

[0106] Above Figure 2 The restoration control system of the seabed sand mining pit based on marine dredged mud in the embodiments of the present invention is described in detail from the perspective of modular functional entities. Next, the restoration control equipment of the seabed sand mining pit based on marine dredged mud in the embodiments of the present invention is described in detail from the perspective of hardware processing.

[0107] Figure 3FIG. 0 is a schematic structural diagram of a control device for repairing a seabed sand mining pit based on marine dredged mud provided by an embodiment of the present invention. The control device 300 for repairing a seabed sand mining pit based on marine dredged mud may vary greatly due to different configurations or performances, and may include one or more processors (central processing units, CPUs) 310 (for example, one or more processors) and a memory 320, and one or more storage media 330 for storing application programs 333 or data 332 (for example, one or more mass storage device terminals). Among them, the memory 320 and the storage media 330 may be transient storage or persistent storage. The program stored in the storage media 330 may include one or more modules (not shown in the figure), and each module may include a series of instruction operations on the control device 300 for repairing a seabed sand mining pit based on marine dredged mud. Further, the processor 310 may be configured to communicate with the storage media 330 and execute a series of instruction operations in the storage media 330 on the control device 300 for repairing a seabed sand mining pit based on marine dredged mud to implement the steps of the above-mentioned method for controlling the repair of a seabed sand mining pit based on marine dredged mud.

[0108] The control device 300 for repairing a seabed sand mining pit based on marine dredged mud may further include one or more power supplies 340, one or more wired or wireless network interfaces 350, one or more input / output interfaces 360, and / or one or more operating systems 331, such as Windows Serve, Mac OS X, Unix, Linux, FreeBSD, and so on. Those skilled in the art can understand that Figure 3 the shown structural diagram of the control device for repairing a seabed sand mining pit based on marine dredged mud does not constitute a limitation on the control device for repairing a seabed sand mining pit based on marine dredged mud provided by the present invention, and may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0109] The present invention also provides a computer-readable storage medium. The computer-readable storage medium may be a non-volatile computer-readable storage medium, or may also be a volatile computer-readable storage medium. Instructions are stored in the computer-readable storage medium. When the instructions are run on a computer, the computer is caused to execute the steps of the method for controlling the repair of a seabed sand mining pit based on marine dredged mud.

[0110] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described systems, systems, and units may refer to the corresponding processes in the foregoing method embodiments and will not be described herein again.

[0111] When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to enable a seabed sand mining pit repair control device based on marine dredged mud (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs.

[0112] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for controlling the restoration of a seabed sand mining pit based on marine dredged mud, characterized in that, The method includes: Performing topographic surveying and environmental sample collection and analysis on the seabed sand mining pit to obtain three-dimensional topographic data of the sand mining pit, and improving the marine dredged mud to obtain a repair material; Based on the three-dimensional topographic data and the repair material, performing filling scheme analysis to generate a target filling scheme, and constructing a transportation system combining barge transportation and pipeline transportation, including: analyzing the hydrodynamic conditions in the sand mining pit area for the three-dimensional topographic data, calculating the influence degrees of tidal current, waves, and ocean current on the filling material to obtain a hydrodynamic influence evaluation result; calculating the sediment migration law based on the hydrodynamic influence evaluation result, and combining with the physical properties of the repair material to determine the stability parameters of the filling material in each area to obtain a filling area zoning scheme; dividing the sand mining pit into multiple filling units according to the filling area zoning scheme, determining the specific filling thickness, material ratio, and construction time for each filling unit to obtain a project implementation plan; optimizing the project implementation plan, calculating the connection method between each filling unit to obtain a target filling scheme with reserved settlement space; determining the best transportation route according to the spatial relationship between the storage location of the repair material and the sand mining pit, designing the barge specifications, loading capacity, and positioning system to obtain an offshore transportation plan; designing a pipeline transportation system based on the offshore transportation plan, determining the pipe diameter, flow velocity, transportation pressure, and diffuser parameters to construct a transportation system combining barge transportation and pipeline transportation; Based on the transportation system, filling the repair material into the sand mining pit in layers of bottom layer, middle layer, and surface layer, and performing vibration compaction and underwater grouting treatment on each layer of filling body to obtain a filling structure; Constructing a three-layer protection structure on the surface of the filling structure, and adding gabion cages and energy dissipation structures in high-scour-risk areas to obtain an erosion-resistant surface system; Evaluating the repair effect of the erosion-resistant surface system according to a pre-set monitoring network to obtain a repair effect evaluation database.

2. The method for controlling the repair of a seabed sand mining pit based on marine dredged mud according to claim 1, wherein The performing topographic surveying and environmental sample collection and analysis on the seabed sand mining pit to obtain three-dimensional topographic data of the sand mining pit, and improving the marine dredged mud to obtain a repair material includes: Using a multi-beam sonar system and a side-scan sonar system to survey the seabed sand mining pit, and performing three-dimensional modeling processing on the survey data through marine geographic information system software to obtain three-dimensional topographic data; Setting multiple bottom sediment sample collection points inside and around the sand mining pit, collecting bottom sediment samples at a specific depth from each point, and performing laboratory analysis on the samples to obtain environmental quality parameters; According to the topographic data and the environmental quality parameters, constructing an evaluation index system for the state of the sand mining pit, and performing zonal evaluation on the sand mining pit to obtain the division of repair priority and difficulty level; Performing physical property detection and chemical composition analysis on the dredged mud sample, classifying and rating the dredged mud according to engineering applicability indicators and environmental safety indicators to obtain dredged mud characteristic data; According to the dredged mud characteristic data, adding a solidifying agent and a stabilizing agent to the heavy metal-polluted dredged mud for solidification and stabilization treatment, and adding an oxidizing agent and a catalyst to the organic-polluted dredged mud for chemical oxidation treatment to obtain harmless dredged mud; The harmless dredged mud is added with aggregate and fiber materials for strength enhancement treatment, and permeability materials and modifiers are added for drainage performance adjustment to obtain a repair material.

3. The method for controlling the repair of a seabed sand mining pit based on marine dredged mud according to claim 1, wherein Based on the transportation system, the repair material is filled into the sand excavation pit in layers of bottom layer, middle layer, and surface layer, and vibration compaction and underwater grouting treatment are carried out on each layer of filling body to obtain a filling structure, including: Using the transportation system, the repair material mixed with aggregate is directionally placed at the deepest part of the sand excavation pit to form the bottom filling material, and the filling thickness is controlled according to the depth gradient of the sand excavation pit to obtain the bottom filling body; The bottom filling body is vibrated using underwater vibration compaction equipment, and the vibration frequency and amplitude are adjusted according to the density of the filling material, and the surface after compaction is leveled to obtain a dense bottom foundation; The repair material mixed with a curing agent is transported through the transportation system in sections by area above the bottom foundation to form the middle filling body, and a specific gradient change is maintained between the middle filling body and the bottom foundation to obtain a stepped filling structure; Underwater grouting treatment is carried out on the stepped filling structure, and the grouting points are arranged in a grid pattern, and the grouting pressure and grouting time are determined according to the size of the filling area and the material properties to obtain a firmly internally connected middle layer reinforcement; The mixture of improved dredged mud and fine sand is transported to the surface of the middle layer reinforcement, the surface layer thickness and surface flatness are controlled, and the grid anchoring treatment is carried out on the area in contact with the pit wall to obtain a filling structure anchored and connected to the pit wall.

4. The method for controlling the repair of a seabed sand mining pit based on marine dredged mud according to claim 1, wherein A three-layer protection structure is constructed on the surface of the filling structure, and gabion cages and energy dissipation structures are added in areas with high scouring risk to obtain an erosion-resistant surface system, including: According to the surface characteristics and hydrodynamic conditions of the filling structure, a mixture of fine sand and clay with a specific particle size is prepared as the transition layer material, and the transition layer material is laid on the surface of the filling structure to obtain a transition protection layer; Judge whether the transition protection layer meets the bottom connection requirements. If it meets, gravel and cementing material are mixed and the transition protection layer is covered to form the middle protection layer to obtain a stable structure; Judge the anti-scouring performance of the middle protection layer. If the anti-scouring performance index is lower than the set threshold, the proportion of the cementing material is increased for reinforcement treatment; if the anti-scouring performance index is higher than the threshold, natural materials are selected to cover the middle protection layer to obtain a three-layer protection structure; Analyze the water flow action on the filling structure, calculate the water flow velocity and scouring intensity in each area, and when the scouring intensity exceeds the bearing capacity of the protection layer, it is determined as a high scouring risk area to obtain a distribution map of the protection strengthening area; Judge the position and range of the protection strengthening area. When it is located at the pit edge and the water flow concentration area, a gabion cage structure is laid, and the edge of the cage is buried in the bottom layer, and the cages are connected by connecting lines to obtain an anti-scouring structure; Judge the water flow velocity around the anti-scouring structure. When the velocity exceeds the critical value, a dissipation device composed of rockfill or concrete blocks is set up to carry out diversion and energy dissipation treatment on the incoming water flow to obtain an erosion-resistant surface system.

5. The method for controlling the repair of a seabed sand mining pit based on marine dredged mud according to claim 4, wherein The anti-scour performance of the middle protective layer is judged. If the anti-scour performance index is lower than the set threshold, the proportion of cementing material is increased for reinforcement. If the anti-scour performance index is higher than the threshold, natural materials are selected to cover the middle protective layer to obtain a three-layer protective structure, including: Take samples of the middle protective layer for anti-scouring test, measure the loss of protective layer materials per unit time under water scouring, calculate the material loss rate, and obtain the basic anti-scouring data; Compare and analyze the anti-scour basic data with the hydrodynamic impact assessment results, calculate the anti-scour performance index of the middle protective layer in different areas, and obtain an anti-scour performance distribution map; Determine the anti-scour performance threshold value according to the mechanical properties of the material and the engineering experience value, compare the anti-scour performance index with the threshold value, mark the area with an index lower than the threshold value, and obtain the distribution of the reinforced area; The proportion of cementing material is increased in the middle protective layer of the reinforced area, the amount of cementing material added is determined according to the difference between the anti-scour performance index and the threshold value in different areas, and the cementing material is supplemented to obtain the reinforced middle protective layer; Select natural materials that match the surrounding seabed environment as surface materials, determine the particle size and thickness of the surface materials according to the water depth, wave conditions and seabed type, form a surface protective layer design plan, and obtain the surface formula; The material of the surface layer formula is evenly covered on the surface of the middle protective layer, and the covering thickness and flatness are controlled to make a smooth transition between the surface and the surrounding seabed elevation, thereby obtaining a three-layer protective structure.

6. The method for controlling the repair of a seabed sand mining pit based on marine dredged mud according to claim 1, wherein The repair effect evaluation of the anti-erosion surface system is performed according to the preset monitoring network to obtain a repair effect evaluation database, including: Install settlement monitoring points, water flow monitoring equipment and pore pressure sensors at key locations of the anti-erosion surface system to collect settlement data, water flow parameters and pore water pressure data to obtain raw monitoring data; Processing the raw monitoring data, removing abnormal values, calculating sedimentation rate, water flow velocity change and pressure change trend, and obtaining processed monitoring data; Comparing the processed monitoring data with the design standard value to determine whether the settlement of the filling body exceeds the reserved settlement amount and whether the pore water pressure reaches a stable state, thereby obtaining a stability determination result; Underwater sonar scanning of the anti-erosion surface system measures changes in surface morphology, calculates erosion depth and range, determines the integrity of the protective structure, and obtains an anti-erosion effect evaluation; According to the stability determination results and anti-erosion effect evaluation, the repair area is graded and assessed, and the area that needs to be reinforced or strengthened is marked to obtain the subsequent maintenance area identification; The monitoring data, stability determination results, anti-erosion effect evaluation and subsequent maintenance area identification are integrated and stored, an information system including time series data and spatial distribution data is established, and a restoration effect evaluation database is obtained.

7. A seabed sand mining pit restoration control system based on marine dredged mud, characterized in that, Used to implement the seabed sand pit repair control method based on marine dredging mud as described in any one of claims 1 to 6, the seabed sand pit repair control system based on marine dredging mud comprises: The collection module is used to conduct topographic mapping and environmental sample collection and analysis of the seabed sand mining pits, obtain the three-dimensional topographic data of the sand mining pits, and improve the marine dredged mud to obtain restoration materials; An analysis module for analyzing a filling scheme based on the three-dimensional terrain data and the repair material, generating a target filling scheme, and constructing a transportation system combining barge transportation and pipeline transportation; A filling module for filling the repair material into the sand excavation pit layer by layer according to the bottom layer, the middle layer, and the surface layer based on the transportation system, and performing vibration compaction and underwater grouting treatment on each layer of filling body to obtain a filling structure; A construction module for constructing a three-layer protection structure on the surface of the filling structure, and adding gabion cages and energy dissipation structures in high-scour-risk areas to obtain an erosion-resistant surface system; An evaluation module for evaluating the repair effect of the erosion-resistant surface system according to a preset monitoring network to obtain a repair effect evaluation database.

8. A control device for repairing a seabed sand mining pit based on marine dredged mud, characterized in that, It includes a memory and a processor. The memory stores a computer program that can run on the processor. When the processor executes the computer program, it implements the method for controlling the repair of the seabed sand excavation pit based on marine dredged mud according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is run by the processor, the processor is caused to execute the method for controlling the repair of the seabed sand excavation pit based on marine dredged mud according to any one of claims 1 to 6.

Images