River flood risk dynamic assessment and unmanned precise dredging equipment and method
By using unmanned dredging equipment with split, integrated, or hybrid hardware architectures, combined with grid-based topographic mapping and PID closed-loop control, dynamic assessment of river flood risk and precise dredging have been achieved. This solves the problems of insufficient monitoring, poor equipment coordination, and significant pollution in existing technologies, thereby improving the efficiency and stability of river management.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- FUJIAN PROVINCIAL INVESTIGATION DESIGN & RES INST OF WATER CONSERVANCY & HYDROPOWER
- Filing Date
- 2026-05-08
- Publication Date
- 2026-06-09
AI Technical Summary
Existing river dredging operations suffer from problems such as low monitoring frequency, reliance on manual experience, poor equipment coordination, significant pollution, extensive operations, and high costs, making it impossible to achieve precise, targeted dredging and dynamic assessment of river flood risks.
The unmanned dredging equipment adopts a split, integrated or hybrid hardware architecture, combined with grid-based topographic mapping, dual-threshold quantization judgment and PID closed-loop control. Through unmanned high-frequency mapping unit, intelligent analysis and decision-making unit and unmanned precision dredging unit, it can achieve ±2cm accuracy in excavation depth control and closed-loop transportation, preserve the original soil layer of the riverbed, and use a re-measurement and re-dredging mechanism to ensure the dredging effect.
It has enabled efficient and precise river dredging operations, improved the flood discharge capacity of rivers, reduced treatment costs, avoided soil disturbance and secondary pollution, adapted to different river conditions, and improved operational efficiency and equipment stability.
Smart Images
Figure CN122175385A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of water conservancy and river management technology, specifically to a dynamic assessment of river flood risk and an unmanned precision dredging device and method. Background Technology
[0002] River siltation directly reduces the cross-sectional area of flow, decreasing flood control and drainage capacity, and is a core issue in flood control management of plain river networks and other waterways. River dredging, as a primary means of siltation control, has gradually integrated underwater mapping and unmanned equipment operation technologies to replace traditional manual labor. Rivers with different hydrological conditions have varying requirements for the accuracy, timeliness, and ecological protection of dredging operations. In routine flood control management, it is necessary to simultaneously complete underwater topographic monitoring, siltation risk assessment, and targeted dredging operations. There is a clear practical application need within the industry for dredging technologies that integrate data collection, risk assessment, and precise operation.
[0003] Current river dredging operations suffer from several technical shortcomings. Manual inspections and periodic surveys are infrequent, failing to identify early signs of siltation. Dredging decisions rely heavily on personnel experience, lacking quantifiable standards. Conventional dredging equipment employs full-section excavation, easily disturbing the original riverbed soil and damaging the aquatic environment. Furthermore, surveying and dredging equipment operate independently, preventing data sharing and collaboration. The lack of standardized post-operation review processes leads to incomplete dredging or over-excavation, and mud transport is prone to leakage and pollution. Unmanned equipment lacks sufficient collaborative control capabilities, hindering on-demand, targeted dredging based on flood risk, resulting in high overall treatment costs. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a dynamic assessment system for river flood risk and an unmanned, precise dredging device and method. This invention utilizes three compatible hardware architectures—split-type, integrated, and hybrid—combined with gridded topographic mapping, dual-threshold quantification, and PID closed-loop control to establish a dynamic assessment system for river flood risk and an unmanned, precise dredging system. An unmanned high-frequency mapping unit collects underwater topographic data, an intelligent analysis and decision-making unit performs data calculations and issues dredging commands, an unmanned precise dredging unit controls the excavation depth with an accuracy of ±2cm, and an onshore sludge treatment unit transports and processes the sludge in a closed system. Throughout the operation, the original riverbed soil layer is preserved to avoid soil disturbance and secondary pollution, and a re-surveying and re-excavation mechanism ensures the dredging effect. This invention solves the problems of poor coordination, extensive operation, and significant pollution associated with traditional dredging equipment. It is adaptable to different river conditions, improves dredging efficiency, stabilizes river flood control capacity, and reduces the overall investment in river management.
[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: On the one hand, a dynamic assessment and unmanned precision dredging device for river flood risk, the device includes an unmanned high-frequency mapping unit, an intelligent analysis and decision-making unit, an unmanned precision dredging unit, and an onshore sludge treatment and disposal unit, wherein the unmanned high-frequency mapping unit, the unmanned precision dredging unit, and the onshore sludge treatment and disposal unit are all bidirectionally connected to the intelligent analysis and decision-making unit;
[0006] The unmanned high-frequency mapping unit is a lightweight unmanned vessel without a dredging mechanism. The vessel is equipped with a multibeam echo sounder, an RTK-GNSS module and an inertial navigation system, which are used to collect underwater topographic data of the river channel in a grid and construct a measured three-dimensional topographic model.
[0007] The intelligent analysis and decision-making unit is deployed on a shore-based or cloud server and has a built-in terrain registration module, siltation thickness calculation model, flood risk assessment model and dual threshold judgment module, which are used for terrain data processing and dredging task instructions.
[0008] The unmanned precision dredging unit is an unmanned dredging vessel with dynamic positioning function. The hull integrates a variable depth sluice suction mechanism, a mud pump system, an obstacle detection module and a sealed conveying interface. The variable depth sluice suction mechanism consists of a depth sensor, a lifting cylinder and a PID closed-loop control module. The depth sensor and the lifting cylinder are connected by a signal.
[0009] The onshore sludge treatment and disposal unit is sealed and connected to a closed conveying interface via a flexible floating pipe, and is used to receive and process dredging sludge.
[0010] Furthermore, the digging depth control accuracy of the variable depth auger suction mechanism is ±2cm, and the depth sensor collects the vertical position of the auger suction head in real time and feeds it back to the PID closed-loop control module.
[0011] Furthermore, the dredging equipment adopts a split, integrated, or hybrid architecture; the split architecture means that the surveying unit and the dredging unit are on separate carriers, the integrated architecture means that the surveying and dredging modules are integrated on the same carrier, and the hybrid architecture means that a single surveying unit coordinates with multiple dredging units.
[0012] Furthermore, the dynamic positioning system of the unmanned precision dredging unit is bound to the RTK-GNSS module for positioning, and the obstacle detection module is linked to the navigation control and PID closed-loop control modules for bidirectional data linkage.
[0013] Furthermore, the mud pump output end is coaxially and sealed to the sealed conveying interface, and the flexible floating pipe, the sealed conveying interface, and the onshore sludge treatment and disposal unit are all detachably and sealed to form a leak-free conveying channel throughout the entire process.
[0014] On the other hand, a method for dynamic assessment of river flood risk and unmanned precision dredging, the specific steps of which are as follows:
[0015] S100 controls the unmanned high-frequency mapping unit to cruise in full coverage according to the preset grid unit, collect underwater topographic data and build a measured topographic model;
[0016] S200: Register the measured terrain model with the standard terrain model coordinates and compare the elevations, and calculate the siltation thickness and flood risk index grid by grid.
[0017] S300: Execute dual threshold linkage judgment. Only when the flood risk index is greater than the risk threshold and the siltation thickness is greater than the dredging thickness threshold, will the high-risk area be locked. If either condition is not met, return to S100 to continue monitoring.
[0018] S400: Based on the coordinates and obstacle data of high-risk areas, generate a full-coverage navigation path and a depth control matrix that corresponds one-to-one with the grid accumulation thickness;
[0019] The S500 controls the unmanned dredging unit to navigate along the path, using the depth control matrix as the target value and the depth sensor as the feedback value for PID closed-loop adjustment, and stops after dredging to the standard riverbed elevation.
[0020] S600: The mud is transported to the onshore unit via a mud pump and a flexible floating pipe in a closed manner to complete solid-liquid separation.
[0021] S700: After dredging, a re-measurement is triggered to recalculate the siltation thickness and flood risk. If the target is not met, a supplementary dredging task is generated and steps S400 to S600 are repeated. If the target is met, the archived data is stored.
[0022] Furthermore, the formula for calculating the sediment thickness in step S200 is as follows:
[0023]
[0024] in, For the first river channel The accumulation thickness of grid cell number 1; For the first river channel Standard design riverbed elevation for grid cell number 1; For the first river channel The measured current riverbed elevation of grid cell number i; i is the longitudinal grid number of the river channel; j is the transverse grid number of the river channel.
[0025] The formula for calculating the flood risk index is:
[0026]
[0027] in, The river flood risk index This refers to the actual flood discharge capacity of the river channel under siltation conditions. This refers to the theoretical flood discharge capacity of a river under standard design conditions.
[0028] Furthermore, the dual threshold determination in step S300 employs the following logic:
[0029]
[0030]
[0031] in, To preset the flood risk warning threshold, The value is 0.7; To preset the dredging start thickness threshold, The value is 0.3m; both conditions must be met simultaneously for dredging to begin.
[0032] Furthermore, in step S500, the PID closed-loop control strictly adjusts the excavation depth of the cutter head with the depth control matrix as the target value and the real-time data collected by the depth sensor as the feedback value. The cutter head stops excavating when it reaches the standard riverbed elevation, preserving the original soil layer of the riverbed.
[0033] Furthermore, in step S700, the resurvey uses the same gridded path, the same grid size, and the same standard terrain model as in step S100 for comparison. The supplementary excavation task regenerates the navigation path and depth control matrix based on the siltation thickness and flood risk data after the resurvey.
[0034] Compared with existing technologies, this dynamic assessment of river flood risk and unmanned precision dredging equipment and method has the following advantages:
[0035] I. This invention utilizes a modular and multi-architecture compatible hardware layout, combined with a variable suction chaff extraction structure featuring deep closed-loop feedback, to construct an integrated collaborative equipment system encompassing surveying, decision-making, dredging, and disposal. The equipment is equipped with a high-precision positioning and detection module, achieving centimeter-level control of excavation depth. A detachable, sealed conveying structure ensures leak-free mud transfer, while simultaneously differentiating between surveying and dredging functions, reducing idle energy consumption. This hardware configuration is adaptable to various river conditions, solving the problems of limited functionality and poor coordination inherent in traditional equipment. It precisely matches the operational needs of silted areas, reduces ineffective work areas, and improves operational stability and efficiency.
[0036] II. This invention utilizes a method combining gridded topographic mapping and dual-threshold quantification, along with PID closed-loop control and a re-survey and supplementary excavation mechanism, to achieve precise dredging operations driven by flood risk. The method uses the standard riverbed elevation as the operational boundary, fully preserving the original riverbed soil layer. Operational parameters are dynamically adjusted based on real-time data. After dredging, a unified standard is used to complete topographic verification, forming a closed-loop data process. This operational logic avoids riverbed soil disturbance, prevents secondary pollution, and enables routine monitoring of siltation hazards, ensuring stable river flood discharge capacity and reducing overall investment in river management.
[0037] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description
[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.
[0039] Figure 1 This is a block diagram of the overall architecture of the dredging system of the present invention;
[0040] Figure 2 This is a flowchart illustrating the logic control of the dredging method of the present invention.
[0041] Figure 3 This is a schematic diagram of the steps in the dredging method of the present invention;
[0042] Figure 4 This is a schematic diagram of the unmanned precision dredging vessel of the present invention;
[0043] Figure 5 This is a schematic diagram of the onshore sludge treatment and disposal unit of the present invention. Detailed Implementation
[0044] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.
[0045] This embodiment discloses a dynamic assessment of river flood risk and an unmanned precision dredging device and method. The device can adopt three hardware architectures: split type, integrated type, and hybrid type. The whole system consists of an unmanned high-frequency mapping unit, an intelligent analysis and decision-making unit, an unmanned precision dredging unit, and an onshore sludge treatment and disposal unit.
[0046] The operation is based on gridded underwater topographic data collection. Three sets of core mathematical formulas are used to calculate the siltation thickness and flood risk. A risk warning threshold of 0.7m and a dredging start thickness threshold of 0.3m are set. Combined with PID closed-loop control, the excavation depth is adjusted with an accuracy of ±2cm. After dredging, standardized re-measurement is carried out. Areas that do not meet the standards are re-excavated. The original soil layer of the riverbed is preserved throughout the operation. The mud is transported and treated using closed pipelines.
[0047] The specific implementation process is as follows:
[0048] This equipment features three hardware deployment options to suit different river conditions. In the split-type architecture, the unmanned high-frequency mapping unit and the unmanned precision dredging unit use separate equipment, suitable for long-term monitoring of large-scale rivers. In the integrated architecture, the underwater mapping module and the dredging module are installed on the same unmanned vessel, suitable for rapid dredging of small-scale rivers. In the hybrid architecture, one unmanned high-frequency mapping unit works simultaneously with multiple unmanned precision dredging units, suitable for concentrated dredging of contiguous river networks. In all three deployment methods, all equipment establishes two-way wireless communication with the intelligent analysis and decision-making unit, enabling real-time transmission of collected data and synchronous transmission of control commands. Figure 1 As shown, the entire dredging system consists of an unmanned high-frequency mapping unit, an intelligent analysis and decision-making unit, an unmanned precision dredging unit, and an onshore sludge treatment and disposal unit. Each unit achieves data interaction and command transmission through a communication module.
[0049] The unmanned high-frequency mapping unit is equipped with a multibeam echo sounder, an RTK-GNSS module, and an inertial navigation system to continuously collect underwater elevation and spatial positioning data. The unmanned precision dredging unit is equipped with a dynamic positioning system. The hull houses a variable depth sluice suction mechanism, a mud pump system, an obstacle detection module, and a sealed delivery interface. The variable depth sluice suction mechanism consists of a depth sensor, a lifting cylinder, and a PID closed-loop control module. The depth sensor is connected to the lifting cylinder, and the equipment's dredging depth control accuracy is ±2cm. Figure 4 As shown, the unmanned precision dredging unit mainly includes a control module, a positioning module, a communication module, a sludge storage facility, and a variable depth suction mechanism, capable of independently completing dredging operations and data transmission. The obstacle detection module transmits data bidirectionally with the navigation control module and the PID closed-loop control module, adjusting the navigation route and the working status of the suction mechanism in real time. The output end of the sludge pump system is coaxially and fixedly sealed to the sealed conveying interface. The flexible floating pipe's two ends are detachably and sealed to the sealed conveying interface and the onshore sludge treatment and disposal unit, forming a fully enclosed sludge conveying pipeline. Figure 5As shown, the onshore sludge treatment and disposal unit is equipped with a power supply module, control module, positioning module, communication module, sludge-water separation facility, supernatant treatment system, and sludge storage facility, which can complete the reception, separation, and storage of sludge.
[0050] The intelligent analysis and decision-making unit is installed on the shore-based server and includes a terrain registration module, a siltation thickness calculation model, a flood risk assessment model, and a dual-threshold judgment module to control the orderly implementation of the entire operation process. For example... Figure 2 As shown, after the operation is started, it first enters the routine monitoring program. The intelligent analysis and decision unit sends a cruise command to control the unmanned high-frequency mapping unit to complete the full-area cruise of the river along the preset grid unit. Simultaneously, it collects underwater topographic elevation, ship positioning coordinates and attitude correction data. All raw data are transmitted to the intelligent analysis and decision unit in real time. The system integrates the data and generates the current measured three-dimensional topographic model of the river.
[0051] The intelligent analysis and decision-making unit aligns the measured 3D terrain model with the preset standard terrain model in terms of coordinates and compares their elevations, then calculates the corresponding values one by one according to the vertical and horizontal grid divisions. The siltation thickness is calculated using the following formula:
[0052]
[0053] in, For the first river channel The accumulation thickness of grid cell number 1; For the first river channel Standard design riverbed elevation for grid cell number 1; For the first river channel The measured current riverbed elevation of grid cell number i; i is the longitudinal grid number of the river channel; j is the transverse grid number of the river channel.
[0054] The formula for calculating the flood risk index is:
[0055]
[0056] in, The river flood risk index This refers to the actual flood discharge capacity of the river channel under siltation conditions. The theoretical flood discharge capacity of the river under standard design conditions is calculated, and the two sets of calculation results are simultaneously stored in the system's local database.
[0057] The system uses a dual-threshold determination formula to decide whether to initiate dredging. The determination formula is as follows:
[0058]
[0059]
[0060] in, To preset the flood risk warning threshold, The value is 0.7; To preset the dredging start thickness threshold, The value is 0.3m. The system locks the spatial coordinates of the corresponding grid area and generates a dredging operation command only when both sets of judgment conditions are met simultaneously. If either set of conditions is not met, the system continues to carry out routine monitoring of the river topography and does not initiate dredging operations.
[0061] The intelligent analysis and decision-making unit integrates the coordinates of high-risk areas with real-time water obstacle data collected by the obstacle detection module to plan a full-coverage navigation route for the unmanned dredging vessel. Simultaneously, it combines the siltation thickness values of each grid unit to generate depth control data for the suction head, corresponding one-to-one with the grid location. The navigation route and depth control data are simultaneously sent to the unmanned precision dredging unit. For example... Figure 3 As shown, the dredging operation is carried out in sequence according to the steps of data collection, risk quantification, dual threshold determination, path planning, precise execution, coordinated response, effect verification and iteration.
[0062] After receiving instructions, the unmanned precision dredging unit automatically travels to the target work area and moves at a constant speed along the planned navigation route. The PID closed-loop control module uses depth control data as the adjustment standard and the real-time data of the dredger head position collected by the depth sensor as a reference to continuously adjust the extension and retraction length of the lifting cylinder, thereby changing the vertical digging depth of the dredger head. Excavation stops immediately after the dredger head reaches the standard riverbed elevation, preserving the original soil layer of the riverbed throughout the operation to prevent damage to the original soil structure.
[0063] The sludge generated during dredging operations is pressurized and transported by ship-mounted sludge pumps, and then transported in a fully enclosed manner through flexible floating pipes. After being transported to the onshore sludge treatment and disposal unit, the sludge undergoes solid-liquid separation treatment. The separated water is discharged centrally, and the separated solid sludge is stored and treated centrally.
[0064] After dredging is completed, the system automatically initiates a resurveying operation. The unmanned high-frequency mapping unit uses the same grid route, grid size, and terrain comparison standards as the initial survey to collect secondary topographic data of the work area. Based on the resurvey data, the system recalculates the siltation thickness and flood risk index. If the calculated values do not meet the safety standards, the system generates a supplementary dredging task, replans the navigation route and depth control data, and carries out supplementary dredging operations. When the calculated values meet the safety standards, the resurvey data is synchronously stored in the topographic database of the intelligent analysis and decision-making unit, and the system completes the storage and organization of all operational data.
[0065] This embodiment fully implements three hardware architectures: split, integrated, and hybrid, to meet the operational needs of rivers of different sizes. A depth control accuracy of ±2cm allows for strict control of the excavation range, while a fully enclosed conveying structure prevents mud leakage. Dual threshold value determination accurately delineates the work area, PID closed-loop control adjusts the working depth based on the siltation thickness of each grid, and the re-measurement and data storage process ensures the quality of dredging operations. The entire operational process, including data acquisition, numerical calculation, and equipment operation steps, is clearly defined and can be stably applied to dredging operations in various types of waterways.
[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. A dynamic assessment device for river flood risk and unmanned precision dredging, characterized in that, The equipment includes an unmanned high-frequency mapping unit, an intelligent analysis and decision-making unit, an unmanned precision dredging unit, and an onshore sludge treatment and disposal unit. The unmanned high-frequency mapping unit, the unmanned precision dredging unit, and the onshore sludge treatment and disposal unit are all bidirectionally connected to the intelligent analysis and decision-making unit. The unmanned high-frequency mapping unit is a lightweight unmanned vessel without a dredging mechanism. The vessel is equipped with a multibeam echo sounder, an RTK-GNSS module and an inertial navigation system, which are used to collect underwater topographic data of the river channel in a grid and construct a measured three-dimensional topographic model. The intelligent analysis and decision-making unit is deployed on a shore-based or cloud server and has a built-in terrain registration module, siltation thickness calculation model, flood risk assessment model and dual threshold judgment module, which are used for terrain data processing and dredging task instructions. The unmanned precision dredging unit is an unmanned dredging vessel with dynamic positioning function. The hull integrates a variable depth dredging mechanism, a mud pump system, an obstacle detection module and a sealed conveying interface. The variable depth dredging mechanism consists of a depth sensor, a lifting cylinder and a PID closed-loop control module. The depth sensor and the lifting cylinder are connected by a signal. The onshore sludge treatment and disposal unit is sealed and connected to a closed conveying interface via a flexible floating pipe, and is used to receive and process dredging sludge.
2. The river flood risk dynamic assessment and unmanned precision dredging equipment according to claim 1, characterized in that, The digging depth control accuracy of the variable depth auger suction mechanism is ±2cm. The depth sensor collects the vertical position of the auger suction head in real time and feeds it back to the PID closed-loop control module.
3. The river flood risk dynamic assessment and unmanned precision dredging equipment according to claim 1, characterized in that, The dredging equipment adopts a split, integrated, or hybrid architecture; the split type has separate carriers for the surveying unit and the dredging unit, the integrated type integrates the surveying and dredging modules into the same carrier, and the hybrid type has a single surveying unit cooperating with multiple dredging units.
4. The river flood risk dynamic assessment and unmanned precision dredging equipment according to claim 1, characterized in that, The dynamic positioning system of the unmanned precision dredging unit is bound to the RTK-GNSS module for positioning, and the obstacle detection module is linked to the navigation control and PID closed-loop control modules for bidirectional data linkage.
5. The river flood risk dynamic assessment and unmanned precision dredging equipment according to claim 1, characterized in that, The mud pump output end is coaxially and sealed to the sealed conveying interface. The flexible floating pipe, the sealed conveying interface, and the onshore sludge treatment and disposal unit are all detachably and sealed to form a leak-free conveying channel throughout the entire process.
6. A method for dynamic assessment of river flood risk and unmanned precision dredging, the method being applicable to the river flood risk dynamic assessment and unmanned precision dredging equipment described in any one of claims 1-5, characterized in that, The method includes: S100 controls the unmanned high-frequency mapping unit to cruise in full coverage according to the preset grid unit, collect underwater topographic data and build a measured topographic model; S200: Register the measured terrain model with the standard terrain model coordinates and compare the elevations, and calculate the siltation thickness and flood risk index grid by grid. S300: Execute dual threshold linkage judgment. Only when the flood risk index is greater than the risk threshold and the siltation thickness is greater than the dredging thickness threshold, will the high-risk area be locked. If either condition is not met, return to S100 to continue monitoring. S400: Based on the coordinates and obstacle data of high-risk areas, generate a full-coverage navigation path and a depth control matrix that corresponds one-to-one with the grid accumulation thickness; The S500 controls the unmanned dredging unit to navigate along the path, using the depth control matrix as the target value and the depth sensor as the feedback value for PID closed-loop adjustment, and stops after dredging to the standard riverbed elevation. S600: The mud is transported to the onshore unit via a mud pump and a flexible floating pipe in a closed manner to complete solid-liquid separation. S700: After dredging, a re-measurement is triggered to recalculate the siltation thickness and flood risk. If the target is not met, a supplementary dredging task is generated and steps S400 to S600 are repeated. If the target is met, the archived data is stored.
7. The method for dynamic assessment of river flood risk and unmanned precision dredging according to claim 6, characterized in that, The formula for calculating the siltation thickness in step S200 is as follows: ； in, For the first river channel The accumulation thickness of grid cell number 1; For the first river channel Standard design riverbed elevation for grid cell number 1; For the first river channel The measured current riverbed elevation of grid cell number i; i is the longitudinal grid number of the river channel; j is the transverse grid number of the river channel. The formula for calculating the flood risk index is: ； in, The river flood risk index This refers to the actual flood discharge capacity of the river channel under siltation conditions. This refers to the theoretical flood discharge capacity of a river under standard design conditions.
8. The method for dynamic assessment of river flood risk and unmanned precision dredging according to claim 6, characterized in that, The dual threshold determination in step S300 uses the following logic: ； ； in, To preset the flood risk warning threshold, The value is 0.7; To preset the dredging start thickness threshold, The value is 0.3m; both conditions must be met simultaneously for dredging to begin.
9. The method for dynamic assessment of river flood risk and unmanned precision dredging according to claim 6, characterized in that, In step S500, the PID closed-loop control strictly adjusts the excavation depth of the cutter head with the depth control matrix as the target value and the real-time data collected by the depth sensor as the feedback value. The cutter head stops excavating when it reaches the standard riverbed elevation, preserving the original soil layer of the riverbed.
10. The method for dynamic assessment of river flood risk and unmanned precision dredging according to claim 6, characterized in that, In step S700, the resurvey uses the same gridded path, grid size, and standard terrain model as step S100 for comparison. The dredging task regenerates the navigation path and depth control matrix based on the siltation thickness and flood risk data after the resurvey.