Digital twinborn simulation method and device for pumping underground salt water to prevent seawater invasion

Abstract

The invention provides a digital twinborn simulation method and a digital twinborn simulation device for pumping underground salt water to prevent seawater intrusion, and belongs to the technical field of seawater intrusion, and the method comprises the following steps: S1, measuring a corresponding value through a physical simulation device, and obtaining physical drainage basin information corresponding to the nature by utilizing a proportionality coefficient and conversion; s2, constructing a multi-temporal-spatial-scale and multi-dimensional digital twinborn model; s3, constructing a digital twinborn model; s4, performing cyclic cross recombination on the data features based on a cyclic cross fusion mechanism, and performing fusion processing on the recombined features by adopting a Gaussian mixture process; and S5, operating the digital twinborn model in the virtual environment, simulating a seawater intrusion condition under a real condition in nature, and realizing disaster monitoring in a physical drainage basin range. According to the method, the digital twinborn technology is fully utilized, real-time synchronization of the physical entity and the virtual model is realized, early warning is provided for possible geological disasters, and decision support is provided for orderly development and utilization of underground water.

Description

Technical Field

[0001] The present invention belongs to the technical field of seawater intrusion, and specifically relates to a digital twin simulation method and device for extracting groundwater to prevent and control seawater intrusion. Background Art

[0002] Seawater intrusion into groundwater refers to the phenomenon that the groundwater level in coastal areas drops sharply due to excessive exploitation of groundwater, the hydrodynamic balance between seawater and freshwater is destroyed, and the salt-fresh water interface moves toward the land. Seawater intrusion increases the osmotic pressure of irrigation groundwater, soil salinization, and the scrapping of irrigation wells, resulting in a decrease in paddy field area, an increase in dry field area, a decrease in the area of ​​irrigated farmland, and an increase in wasteland area. Groundwater is an important source of water for agricultural irrigation, industry, mining, and cities. Once seawater intrusion occurs, it will have an adverse impact on human society. Therefore, the prevention and control of seawater intrusion into groundwater has many positive significances and far-reaching impacts.

[0003] With the continuous development of groundwater system research and the continuous improvement of the simulation degree of groundwater numerical models, the construction of more refined management models requires the development of advanced optimization technologies to solve the management problems of complex groundwater systems. Water resource management problems have evolved from traditional single-objective optimization to multi-objective optimization, and from deterministic optimization problems to stochastic optimization problems. The management models related to groundwater systems often have the characteristics of nonlinearity, non-convexity, randomness, high-dimensional decision variables and multi-objective variables. The existing seawater intrusion simulation methods have the defects of poor detection accuracy and poor timeliness, making it difficult to establish high-precision simulation models and difficult to promote and apply them on a large scale. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, a digital twin simulation method and device for extracting groundwater to prevent seawater intrusion are provided.

[0005] The technical solution adopted by the present invention to solve its technical problem is: This technical solution proposes a digital twin simulation method for extracting groundwater to prevent seawater intrusion, including the following steps: S1: Build a physical simulation device for seawater intrusion, measure the corresponding values ​​through the physical simulation device, and use the proportional coefficient and conversion to obtain the corresponding physical basin information in nature; S2: Feedback the physical watershed information to the watershed virtual twin, build an integrated sky-ground water conservancy perception network, and build a multi-dimensional digital twin model with multiple spatiotemporal scales based on the watershed virtual twin and the integrated sky-ground water conservancy perception network; S3: Build a digital twin model, which includes a watershed information data model, a geographic information reference model, and a multi-dimensional visualization model. The original data in the data model is extracted from data features at multiple spatiotemporal scales and dimensions according to unified data standards and business application requirements. S4: The data features are cyclically cross-reorganized based on the cyclic cross-fusion mechanism, and the reorganized features are fused using a mixed Gaussian process. The fused features are input into the calibration model for calibration, and the digital twin model is calibrated through piecewise linear regression. The calibration process includes multiple rounds of simulation and actual data comparison. S5: Run the digital twin model in a virtual environment to simulate seawater intrusion under real natural conditions. Combined with the hydrological data collected by the integrated sky-ground water conservancy sensing network, the underground reservoir capacity, storage volume, river infiltration and exploitable volume of the physical basin can be predicted, and disaster monitoring within the physical basin can be achieved.

[0006] Preferably, in S2, the integrated sky-ground water conservancy perception network includes the hydrology, water resources, water conservancy projects, soil and water conservation, rivers and lakes, economic, social and ecological environmental information of the physical watershed; the integrated sky-ground water conservancy perception network is capable of sensing the digital terrain of the underlying surface of the watershed, vegetation coverage, water-blocking structures in the river channel, river beach occupation, large hydrological sections and underwater terrain of river sections.

[0007] Preferably, the multi-dimensional digital twin model of multiple time and space scales includes macroscale, mesoscale and microscale; The macro scale includes vector map data, satellite remote sensing image maps and DEM elevation map data; The mesoscale includes satellite remote sensing images, refined manual model data, oblique photography model data and high-precision DEM data; The micro scale includes water conservancy IoT equipment and reservoir dams. Through BIM technology, the equipment model is established and detailed display is realized.

[0008] Preferably, in S3, the watershed information data model includes organizing and collating different information based on knowledge graph technology, constructing association relationships, indicator relationships, and spatial relationships between physical watershed entities through nodes and logical relationships between nodes, forming a data model and a knowledge graph, and integrating related data resources through a unified data model and knowledge graph; The geographic information reference model includes a set of standardized geographic information parsing and storage methods for complex multi-source geographic information. The standardization of geographic information includes the definition of geographic information interoperability, basic data types, modeling rules, and semantics of real-world phenomena. The multi-dimensional visualization model applies various spatial and temporal information of the physical world to build a high-fidelity visual physical model. Through BIM technology, it provides real-time rendering and visualization for simulation based on the temporal and spatial characteristics of the geographical distribution patterns and development process of various elements of joint scheduling, and provides high-fidelity digital mapping of physical space in multiple dimensions and time and space scales.

[0009] Preferably, in S4, the mixed Gaussian process realizes weighted fusion of data, and the formula is as follows: (1) In the formula, F fused represents the fused features, N is the total number of Gaussian components, w i Indicates i The weights of the Gaussian components, represents a Gaussian distribution, F rec are input features, m i , S i Respectively represent i The mean and covariance matrix of the Gaussian components.

[0010] Preferably, use fusion features F fused As input, the groundwater reservoir capacity, storage variable, river infiltration and exploitable volume of the physical watershed are predicted by the piecewise linear regression model, and the predicted output of the physical watershed is obtained as follows: (2) In the formula, y pred represents the predicted output, M is the total number of basis functions used in the model, a j Indicates j The coefficients of the basis functions are used to adjust the contribution of the basis functions to the predicted values. b j Indicates j The bias term of the basis function is used to adjust the output of the basis function. F fused,j Indicates j The fused features; By calculating the error between the predicted output and the actual output, the calibration loss function is obtained: (3) In the formula, L calrepresents the calibration loss function, y real Indicates the actual output, y pred represents the predicted value; Using the gradient descent algorithm to minimize the calibration loss function, the formula for the updated digital twin model parameters is as follows: (4) In the formula, i and i ´ respectively represent the parameters of the digital twin model before and after the update, or represents the learning rate, ▽ θ L cal Represents the gradient of the calibration loss function with respect to the digital twin model parameters.

[0011] A digital twin simulation device for extracting underground salt water to prevent seawater intrusion is used to execute the above-mentioned digital twin simulation method for extracting underground salt water to prevent seawater intrusion. The physical simulation device includes a test sand box, and baffles with uniform holes are respectively connected to both ends of the test sand box. The baffle divides the test sand box into a seawater chamber and a freshwater chamber located on both sides, and a test water chamber located in the middle. The two sides of the test water chamber are connected to the seawater chamber and the freshwater chamber through the holes arranged respectively, and also includes, A constant head mechanism for maintaining the water level balance in the seawater chamber; A pumping mechanism for pumping water from the test water chamber; A pressure measuring mechanism for measuring the pressure of a test water chamber.

[0012] Preferably, the fixed water head mechanism includes a water tank and a water bucket, a baffle is fixedly connected inside the water tank, the baffle divides the water tank into an overflow tank and a fixed water tank, the seawater chamber is connected to the fixed water tank through a joint; the overflow tank is connected to the water bucket through a connecting pipe, a submersible pump is connected inside the water bucket, and the submersible pump can pump the water in the bucket into the fixed water tank.

[0013] Preferably, a water stop plate for sealing the joint is slidably connected inside the joint, the water stop plate is connected to the joint via a tension spring, the seawater chamber is connected to a fixed pipe, a piston is slidably connected inside the fixed pipe, the piston is connected to a magnet that has an attractive effect on the water stop plate, and the magnetic force of the magnet is greater than the elastic force of the tension spring.

[0014] Preferably, a switch that can control the operation of the submersible pump is connected to the fixed tube, and the switch is located on one side of the piston. The piston is connected to the fixed tube through a spring, and the piston is fixedly connected to a sleeve. The sleeve is threadedly connected to a screw, and the screw is connected to the magnet. The water stop plate is connected to a one-way valve that only allows water to flow from the fixed water tank into the seawater chamber.

[0015] Compared with the prior art, the present invention has the following advantages: This application makes full use of digital twin technology to achieve real-time synchronization between physical entities and virtual models, calibrates the digital twin model through piecewise linear regression, uses fusion features as input, and calibrates model parameters through multiple rounds of simulation and actual data comparison to better match the actual situation and ensure the accuracy of the model. It can provide early warning for possible geological disasters and provide decision-making support for the orderly development and utilization of groundwater.

[0016] The physical simulation device proposed in the present application can adjust the water level of the seawater chamber by adjusting the height of the water tank. When the seawater chamber rises, only when the seawater chamber rises to a certain height and the magnet moves a sufficient distance will the water baffle open to allow the water in the seawater chamber to flow into the fixed water tank. When the seawater chamber descends, only when it descends to a certain extent will the piston drive the switch to work and the submersible pump to work to replenish the seawater chamber with water, thereby preventing small-range movement from affecting the simulation of seawater intrusion, and at the same time allowing the seawater chamber to always maintain a sufficiently suitable water level. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 It is the overall flow chart of the present invention; Figure 2 It is a schematic diagram of the overall structure of the present invention; Figure 3 It is a schematic diagram of the structure of the joint part in the present invention.

[0018] Description of reference numerals: 1 test sand box; 2 pumping mechanism; 3 head-fixing mechanism; 4 pressure measuring mechanism; 5 fresh water chamber; 6 sea water chamber; 7 baffle; 8 water tank; 9 water-blocking plate; 10 bucket; 11 submersible pump; 12 peristaltic pump; 13 pressure measuring tube; 14 graduation paper; 15 test water chamber; 16 fixed water tank; 17 overflow tank; 18 fixed pipe; 19 joint; 20 water stop plate; 21 tension spring; 22 piston; 23 sleeve; 24 screw; 25 magnet; 26 spring; 27 switch. DETAILED DESCRIPTION

[0019] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0020] like Figure 1-Figure 3 As shown, this embodiment proposes a digital twin simulation method for extracting underground salt water to prevent seawater intrusion, including the following steps: S1: Build a physical simulation device for seawater intrusion, measure the corresponding values ​​through the physical simulation device, and use the proportional coefficient and conversion to obtain the corresponding physical basin information in nature; S2: Feedback the physical watershed information to the watershed virtual twin, build an integrated sky-ground water conservancy perception network, and build a multi-dimensional digital twin model with multiple spatiotemporal scales based on the watershed virtual twin and the integrated sky-ground water conservancy perception network; S3: Build a digital twin model, which includes a watershed information data model, a geographic information reference model, and a multi-dimensional visualization model. The original data in the data model is extracted from data features at multiple spatiotemporal scales and dimensions according to unified data standards and business application requirements. S4: The data features are cyclically cross-reorganized based on the cyclic cross-fusion mechanism, and the reorganized features are fused using a mixed Gaussian process. The fused features are input into the calibration model for calibration, and the digital twin model is calibrated through piecewise linear regression. The calibration process includes multiple rounds of simulation and actual data comparison. S5: Run the digital twin model in a virtual environment to simulate seawater intrusion under real natural conditions. Combined with the hydrological data collected by the integrated sky-ground water conservancy sensing network, the underground reservoir capacity, storage volume, river infiltration and exploitable volume of the physical basin can be predicted, and disaster monitoring within the physical basin can be achieved.

[0021] In S2, the integrated sky-ground water conservancy perception network includes the hydrology, water resources, water conservancy projects, soil and water conservation, rivers and lakes, economic, social and ecological environmental information of the physical watershed. The integrated sky-ground water conservancy perception network can perceive the digital terrain of the underlying surface of the watershed, vegetation coverage, river water-blocking buildings, river beach occupation, large hydrological sections and underwater terrain of river sections.

[0022] Data is the core element of digital twins. It originates from physical entities, operating systems, sensors, etc., and covers simulation models, environmental data, physical object design data, maintenance data, operating data, etc., and runs through the entire operation process of physical objects. As a data storage platform, digital twins collect various types of raw data and then fuse and process the data to drive the dynamic operation of various parts of the simulation model and effectively reflect various business processes. Therefore, data is the blood of digital twin applications. Without multi-dimensional fusion data, digital twin applications lose their power source.

[0023] This application constructs a real-life physical simulation device to reproduce the panoramic and full-factor situation of the watershed in a refined manner, integrates the data resources of the existing information systems of various water conservancy departments, combines the CIM base with dynamic simulation and deduction capabilities, and organically combines information, technology, equipment and water conservancy management needs. It covers multiple business areas such as watershed overview, watershed flood control monitoring, reservoir monitoring, water conservancy scheduling, etc., fully empowers user business applications, and effectively improves the efficiency of cross-departmental decision-making and resource coordination in water conservancy.

[0024] The integrated sky-ground water conservancy sensing network can timely and accurately collect information on the hydrology, water resources, water conservancy projects, soil and water conservation, rivers and lakes, economic, social and ecological environment of the physical river basin, and comprehensively grasp the digital terrain of the underlying surface of the river basin, vegetation coverage, river water-blocking buildings, river beach occupation, large hydrological sections and underwater terrain of important river sections, providing a basis for "from real to virtual" and supporting the operation of the digital twin river basin.

[0025] Real-time connection and interaction: It is composed of business network, industrial control network, government network, Internet, sensor network and communication protocol, input and output equipment, security facilities and related technologies, realizing efficient connection and transmission, collaborative interactive control and synchronous iterative optimization between physical simulation device, virtual river basin, digital empowerment service, twin river basin data and twin river basin knowledge. Among them, the virtual river basin is the digital mirror of the physical river basin, which is the virtual twin of the digital twin river basin, and the physical simulation device is the physical twin of the digital twin river basin.

[0026] The multi-dimensional digital twin model with multiple spatiotemporal scales includes macroscale, mesoscale and microscale; The macro scale includes vector map data, satellite remote sensing image maps and DEM elevation map data; The mesoscale includes satellite remote sensing images, refined manual model data, oblique photography model data and high-precision DEM data; The micro scale includes water conservancy IoT equipment and reservoir dams. Through BIM technology, the equipment model is established and detailed display is realized.

[0027] In S3, the watershed information data model includes organizing and sorting different information based on knowledge graph technology, building the association relationship, indicator relationship, and spatial relationship between physical watershed entities through nodes and logical relationships between nodes, forming a data model and knowledge graph, and integrating related data resources through a unified data model and knowledge graph; The geographic information reference model includes a set of standardized geographic information parsing and storage methods for complex multi-source geographic information. The standardization of geographic information includes the definition of geographic information interoperability, basic data types, modeling rules, and semantics of real-world phenomena. The multi-dimensional visualization model applies various spatial and temporal information of the physical world to build a high-fidelity visual physical model. Through BIM technology, it provides real-time rendering and visualization for simulation based on the temporal and spatial characteristics of the geographical distribution patterns and development process of various elements of joint scheduling, and provides high-fidelity digital mapping of physical space in multiple dimensions and time and space scales.

[0028] All sensitive data must be desensitized before being used in the system. Data desensitization specifically includes steps such as terrain data desensitization, longitude and latitude desensitization of water conservancy projects, desensitization of basic information such as personnel, and real-time coordinate conversion processing.

[0029] In S4, by enhancing the correlation between different modes, feature fusion is made more complex and sophisticated, the expressiveness of the digital twin model is improved, the reorganized features are fused, and a mixed Gaussian process is used to achieve weighted fusion of data to further improve the accuracy and reliability of the features. The formula is as follows: (1) In the formula, F fused represents the fused features, N is the total number of Gaussian components, w i Indicates i The weights of the Gaussian components, represents a Gaussian distribution, F rec are input features, m i , S i Respectively represent i The mean and covariance matrix of the Gaussian components are obtained by comprehensively processing the features of different modes to obtain a more accurate and stable feature representation.

[0030] Use Fusion Features F fusedAs input, the groundwater reservoir capacity, storage variable, river infiltration and exploitable volume of the physical watershed are predicted by the piecewise linear regression model, and the predicted output of the physical watershed is obtained as follows: (2) In the formula, y pred represents the predicted output, M is the total number of basis functions used in the model, a j Indicates j The coefficients of the basis functions are used to adjust the contribution of the basis functions to the predicted values. b j Indicates j The bias term of the basis function is used to adjust the output of the basis function. F fused,j Indicates j The fused features; By calculating the error between the predicted output and the actual output, the calibration loss function is obtained: (3) In the formula, L cal represents the calibration loss function, y real Indicates the actual output, y pred represents the predicted value; Using the gradient descent algorithm to minimize the calibration loss function, the formula for the updated digital twin model parameters is as follows: (4) In the formula, i and i ´ respectively represent the parameters of the digital twin model before and after the update, or represents the learning rate, ▽ θ L cal Represents the gradient of the calibration loss function relative to the parameters of the digital twin model. The model parameters are adjusted through calibration to better match the actual situation and ensure the accuracy of the model.

[0031] The digital twin simulation device for extracting underground salt water to prevent seawater intrusion is used to execute the above-mentioned digital twin simulation method for extracting underground salt water to prevent seawater intrusion. The physical simulation device includes a test sand box 1, and baffles 7 with uniform holes are respectively connected to both ends of the test sand box 1. The baffle 7 divides the test sand box 1 into a seawater chamber 6 and a freshwater chamber 5 located on both sides, and a test water chamber 15 located in the middle.

[0032] The two sides of the test water chamber 15 are connected to the seawater chamber 6 and the freshwater chamber 5 through arranged holes, and also include a constant head mechanism 3 for maintaining the water level balance of the seawater chamber 6; a pumping mechanism 2 for pumping water from the test water chamber 15; and a pressure measuring mechanism 4 for measuring the pressure of the test water chamber 15.

[0033] The test sand box 1 is made of a 1.2 cm thick acrylic transparent plate. One side can directly observe the seepage phenomenon, and the other side can be installed with a pressure tube or a pressure gauge at a corresponding position to observe the change of liquid pressure during the test. The test water chamber 15 has a length of 160 cm, a width of 10 cm, and a height of 70 cm. The test water chamber 15 is used to fill the washed quartz sand, and a 1 cm*1 cm scale grid is engraved on the front to record the seawater intrusion interface process line during the test.

[0034] The constant water head mechanism 3 includes a water tank 10, the specifications of the water tank 10 are 20 cm in length, 8 cm in width, and 30 cm in height. A baffle 9 is fixedly connected inside the water tank 10, and the baffle 9 is 15 cm high. The baffle 9 divides the water tank 10 into an overflow tank 17 and a constant water tank 16. The constant water tank 16 is connected to the seawater chamber 6 through a connecting pipe, and the connecting pipe is specifically a PU pipe.

[0035] Water outlet valves are set at intervals of 15 cm from bottom to top on the left side of the seawater chamber 6. The lowest tap water valve is connected to the seawater chamber 6 through an 8*6 mm PU tube to control the seawater level during the test. The seawater level can be adjusted by adjusting the height of the water tank 10.

[0036] The fixed water head mechanism 3 also includes a water bucket 10, and the overflow tank 17 is connected to the water bucket 10 through a connecting pipe. A submersible pump 11 with a head of 1.5 m is connected to the water bucket 10. The submersible pump 11 can pump the water in the water bucket 10 into the fixed water tank 16. When the water in the fixed water tank 16 exceeds the fixed water level, the water flow automatically overflows to the overflow tank 17 on the left.

[0037] The length, width and height of the seawater chamber 6 and the freshwater chamber 5 are the same. The freshwater chamber 5 is used to simulate the landward boundary conditions. Water outlet valves are set every 15 cm from top to bottom on the right side of the freshwater chamber 5 to flush the artificial aquifer after the test. A drain pipe is set at the 40 cm valve to maintain the fresh water level at 40 cm during the test.

[0038] The pressure measuring mechanism 4 includes a side pressure plate, which is a PVC white board with a length of 120 cm and a width of 100 cm. A 100 cm long scale paper 14 is pasted on the white board. A group of 9 scale papers 14 are divided into 4 groups. Small holes are provided on the upper and lower sides of the side pressure plate for fixing the pressure measuring tube. The material of the pressure measuring tube is a 6*4 mm acrylic glass tube, which is connected to the pressure measuring port of the test water chamber 15. Compared with traditional PVC tubes, the acrylic glass tube has the functions of being straight and easy to install, and the error caused by manual reading is much smaller than that of traditional PVC tubes.

[0039] Pressure measuring ports and pumping wells are arranged at intervals of 15 cm on the left and right and 10 cm on the top and bottom of the back of the test water chamber 15. The pressure measuring ports are connected to the pressure measuring tube of the pressure measuring plate through a 6*4 mm PU tube. The pumping mechanism 2 includes a peristaltic pump 12, and the pumping well is connected to the peristaltic pump 12 through a silicone tube. The aquifer in the test water chamber 15 can be pumped at a constant flow rate during the test.

[0040] The surface of the baffle 7 and the sides of the test water chamber 15 are paved with filtering units that prevent quartz sand from passing through without affecting the flow of water. The filtering units are geotextiles or screens. The specifications of the baffle 7 are 10 cm long, 10 cm wide, and 10 cm high. A 100-mesh stainless steel screen is laid on the back of the test water chamber 15 to prevent quartz sand from entering the organic glass tube and pumping well of the pressure plate during the test.

[0041] The seawater chamber 6 is connected to a joint 19, and the connecting pipe connected to the fixed water tank 16 is connected to the joint 19. A water stop plate 20 is slidably connected in the joint 19 for sealing the joint 19. The water stop plate 20 is connected to the joint 19 through a tension spring 21. The tension spring 21 is located on the outside of the joint 19. The tension spring 21 can be sleeved on the water stop plate 20. The upper end of the tension spring 21 is connected to the water stop plate 20, and the lower end is connected to the outer wall of the joint 19. Under the elastic force of the tension spring 21, the water stop plate 20 puts the joint 19 in a sealed state.

[0042] The seawater chamber 6 is connected to a fixed pipe 18, in which a piston 22 is slidably connected. The piston 22 is connected to a magnet 25 that has an attractive effect on the water stop plate 20. The magnetic force of the magnet 25 is greater than the elastic force of the tension spring 21. The piston 22 is connected to the fixed pipe 18 through a spring 26.

[0043] A switch 27 for controlling the operation of the submersible pump 11 is connected inside the fixed pipe 18. The switch 27 is located on one side of the piston 22. The piston 22 is fixedly connected with a sleeve 23. The sleeve 23 is threadedly connected with a screw 24. The screw 24 is connected to a magnet 25. The water stop plate 20 is connected with a one-way valve that only allows water to flow from the fixed water tank 16 into the seawater chamber 6. The one-way valve allows water to flow in only one direction.

[0044] When the water level in the fixed water tank 16 becomes high, the water in the fixed water tank 16 can flow into the seawater chamber 6 through the one-way valve. When the water in the seawater chamber 6 is high, due to the action of the one-way valve, the water will not flow into the fixed water tank 16 through the one-way valve, so that the water can only flow in one direction, so that the seawater chamber 6 can flow to the test water chamber 6 better, and the simulation of seawater intrusion can be better realized.

[0045] Among them, the spring 26 is sleeved on the sleeve 23, the sleeve 23 and the fixed tube 18 are slidably connected, the right end of the spring 26 is connected to the piston 22, and the left end is connected to the fixed tube 18. Under the elastic force of the spring 26, the piston 22 can move to the right end of the fixed tube 18. At this time, the magnet 25 is located on one side of the water stop plate 20 and will not cooperate with the water stop plate 20. The upper end of the water stop plate 20 is an iron block, which is convenient for cooperation with the magnet 25.

[0046] The switch 27 can be specifically a proximity switch or a push switch. The switch 27 and the submersible pump 11 are connected to a controller. When it is a proximity switch, when the piston 22 moves to one side of the proximity switch, the proximity switch receives a signal, and the submersible pump 11 is controlled to work through the controller. The switch 27 can be slidably connected to the fixed tube 18. The switch 27 is connected to a small iron block, and the switch 27 can be driven to slide in the fixed tube 18 through an external magnet to adjust the position of the switch 27.

[0047] A proximity switch is a position switch that can be operated without direct mechanical contact with moving parts. When the piston 22 approaches the sensing surface of the switch to the action distance, the switch can be activated without mechanical contact or any pressure, thereby driving the controller to provide control instructions.

[0048] The method of use includes the following steps: S1: Put the wet quartz sand into the test water chamber 15, and compact the quartz sand while putting it in; S2: Discharge water into the test water chamber 15 and adjust the water level in the test water chamber 15 to a specified height; S3: Colored seawater is put into the water bucket 10, and the submersible pump 11 starts to work, so that the colored seawater in the water bucket 10 is pumped into the fixed water tank 16, and the seawater chamber 6 and the test water chamber 15 are separated by a water-proof baffle, and the fresh water in the seawater chamber 6 is replaced by colored seawater, and the water level of the colored seawater is higher than the water level of the test water chamber 15; S4: The test water chamber 15 is connected to the pumping mechanism 2 and the pressure measuring mechanism 4 respectively. The pumping mechanism 2 works to pump water from the test water chamber 15. The pumping mechanism 2 adopts a point-like pumping method to conduct a physical simulation test of seawater intrusion under different pumping intensities and well layout methods; S5: Use a soluble marker pen to draw the salt-fresh water interface on the test sand box 1, record the migration of the salt-fresh water interface at each stage during the test, and draw the seawater intrusion interface process line during the test.

[0049] In the seawater intrusion simulation, when the water in the seawater chamber 6 tends to be stable, the water in the seawater chamber 6 pushes the piston 22 to move, compressing the spring 26. By rotating the screw 24, the distance between the magnet 25 and the water stop plate 20 is adjusted. Through the external magnet, the position of the switch 27 in the fixed tube 18 is adjusted, thereby adjusting the determination of the fluctuation range of the seawater chamber 6.

[0050] When the water level in the seawater chamber 6 increases, the water pressure increases, driving the piston 22 to move to the left, and the piston 22 drives the magnet 25 to move. When the magnet 25 moves to the side of the water stop plate 20, it means that the water level exceeds the threshold. The magnet 25 drives the water stop plate 20 to rise, and the water in the seawater chamber 6 can flow into the fixed water tank 16 through the joint 19.

[0051] When the water level in the seawater chamber 6 decreases, the water pressure decreases, and the spring 26 drives the piston 22 to move to the right. After the piston 22 and the switch 27 cooperate, the submersible pump 11 works. The submersible pump 11 pumps the water in the bucket 10 into the fixed water tank 16, and then flows into the seawater chamber 6 to replenish the seawater chamber 6, preventing a small range of movement from affecting the simulation of seawater intrusion, and at the same time allowing the seawater chamber 6 to always maintain a sufficiently suitable water level.

[0052] Since a large amount of glue is required to bond the test sand box 1, the observation of the toe angle of the seawater intrusion interface is unclear. The wall thickness of the test sand box 1 accounts for 1.2 cm at the bottom. At the same time, due to the side wall effect (the side wall effect means that the gap between the filler and the tower wall is larger than the gap in the middle of the filler layer, so the liquid is easy to flow to the tower wall and affect the mass transfer effect), the water flow at the bottom of the sand box and the side wall of the sand box moves faster than the inside of the aquifer. Therefore, when selecting data, the position and length of the toe angle of the seawater intrusion interface are read 2 cm above the bottom of the test sand box 1. In addition, in order to prevent the deformation and cracking of the sand box caused by the saturation of quartz sand during the test, a detachable stainless steel frame is installed at the bottom and main body of the test sand box 1.

[0053] In S1, quartz sand was placed in the test water chamber 15 and compacted with a stainless steel plate (60 cm × 9.5 cm × 1 cm), and the compaction was as close as possible to the state of the actual aquifer in the field. This test was a single phreatic aquifer with a sand layer thickness of 46 cm.

[0054] The refined quartz sand used is white crystalline with a particle size of 30-40 mesh. Before putting it into the sand box, the quartz sand is repeatedly washed with running water to wash away impurities and dust in the quartz sand so that the particle size distribution is uniform. The quartz sand is screened using 30 mesh, 35 mesh and 40 mesh quartz sand screens respectively.

[0055] In S2, since the tap water itself contains a small amount of air, a large amount of air will also be introduced into the test water chamber 15 during the process of draining water into the test water chamber 15. Therefore, during the test draining process, a small flow rate should be allowed to slowly flow into the test water chamber 15 to prevent large bubbles from entering the test drained water. After draining the water, let it stand for a while and adjust the water level of the sand box until it stabilizes at 40 cm.

[0056] In S3, the fresh water in the seawater chamber 6 was replaced by colored seawater with a water level of 41 cm, and the seawater intrusion process began. At 270 min, the salt-fresh water interface reached a stable state for the first time (the piezometric tube water head and interface morphology remained unchanged within 60 min).

[0057] Since Cl- is the most stable constant ion in seawater, the seawater in this experiment is to add pure NaCl and dye to tap water. The test uses pure NaCl with a concentration of 25 g / L; the dye is carmine (1-(4-sulfonic acid-1-naphthylazo)-2-hydroxy-6,8-naphthalene disulfonic acid trisodium salt). The mutual interference between sodium chloride and carmine during the test can be ignored, and carmine is a food dye with low pollution and strong coloring properties. It does not react with NaCl and quartz sand and is easy to wash, so carmine is used as a colorant in this experiment. In order to ensure that the solute is fully dissolved, a certain amount of colored seawater is prepared for the test before the test.

[0058] In S4, the test ends when the salt-fresh water interface reaches a stable state again (the water head and interface morphology of the piezometer tube remain unchanged within 60 min).

[0059] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A digital twin simulation method for extracting groundwater to prevent seawater intrusion, characterized in that: The following steps are involved: S1: Build a physical simulation device for seawater intrusion, measure the corresponding values ​​through the physical simulation device, and use the proportional coefficient and conversion to obtain the corresponding physical basin information in nature; S2: Feedback the physical watershed information to the watershed virtual twin, build an integrated sky-ground water conservancy perception network, and build a multi-dimensional digital twin model with multiple spatiotemporal scales based on the watershed virtual twin and the integrated sky-ground water conservancy perception network; S3: Build a digital twin model, which includes a watershed information data model, a geographic information reference model, and a multi-dimensional visualization model. Extract data features of multiple spatiotemporal scales and dimensions from the original data in the digital twin model according to unified data standards and business application requirements; S4: The data features are cyclically cross-reorganized based on the cyclic cross-fusion mechanism, and the reorganized features are fused using a mixed Gaussian process. The fused features are input into the calibration model for calibration, and the digital twin model is calibrated through piecewise linear regression. The calibration process includes multiple rounds of simulation and actual data comparison. S5: Run the digital twin model in a virtual environment to simulate seawater intrusion under real natural conditions. Combined with the hydrological data collected by the integrated sky-ground water conservancy sensing network, the underground reservoir capacity, storage volume, river infiltration and exploitable volume of the physical basin can be predicted, and disaster monitoring within the physical basin can be achieved.

2. The digital twin simulation method for extracting groundwater to prevent seawater intrusion according to claim 1 is characterized in that: In S2, the integrated sky-ground water conservancy perception network includes the hydrology, water resources, water conservancy projects, soil and water conservation, rivers and lakes, economic, social and ecological environmental information of the physical watershed. The integrated sky-ground water conservancy perception network can perceive the digital terrain of the underlying surface of the watershed, vegetation coverage, river water-blocking buildings, river beach occupation, large hydrological sections and underwater terrain of river sections.

3. The digital twin simulation method for extracting groundwater to prevent seawater intrusion according to claim 1 is characterized in that: The multi-dimensional digital twin model with multiple spatiotemporal scales includes macroscale, mesoscale and microscale; The macro scale includes vector map data, satellite remote sensing image maps and DEM elevation map data; The mesoscale includes satellite remote sensing images, refined manual model data, oblique photography model data and high-precision DEM data; The micro scale includes water conservancy IoT equipment and reservoir dams. Through BIM technology, the equipment model is established and detailed display is realized.

4. The digital twin simulation method for extracting groundwater to prevent seawater intrusion according to claim 1 is characterized in that: In S3, the watershed information data model includes organizing and sorting different information based on knowledge graph technology, building the association relationship, indicator relationship, and spatial relationship between physical watershed entities through nodes and logical relationships between nodes, forming a data model and knowledge graph, and integrating related data resources through a unified data model and knowledge graph; The geographic information reference model includes a set of standardized geographic information parsing and storage methods for complex multi-source geographic information. The standardization of geographic information includes the definition of geographic information interoperability, basic data types, modeling rules, and semantics of real-world phenomena. The multi-dimensional visualization model applies various spatial and temporal information of the physical world to build a high-fidelity visual physical model. Through BIM technology, it provides real-time rendering and visualization for simulation based on the temporal and spatial characteristics of the geographical distribution patterns and development process of various elements of joint scheduling, and provides high-fidelity digital mapping of physical space in multiple dimensions and time and space scales.

5. The digital twin simulation method for extracting groundwater to prevent seawater intrusion according to claim 1 is characterized in that: In S4, the mixed Gaussian process realizes the weighted fusion of data, and the formula is as follows: （1） In the formula, F fused represents the fused features, N is the total number of Gaussian components, w i Indicates i The weights of the Gaussian components, represents a Gaussian distribution, F rec are input features, μ i , Σ i Respectively represent i The mean and covariance matrix of the Gaussian components.

6. The digital twin simulation method for extracting groundwater to prevent seawater intrusion according to claim 5 is characterized in that: Use Fusion Features F fused As input, the groundwater reservoir capacity, storage variable, river infiltration and exploitable volume of the physical watershed are predicted by the piecewise linear regression model, and the predicted output of the physical watershed is obtained as follows: （2） In the formula, y pred represents the predicted output, M is the total number of basis functions used in the model, a j Indicates j The coefficients of the basis functions are used to adjust the contribution of the basis functions to the predicted values. b j Indicates j The bias term of the basis function is used to adjust the output of the basis function. F fused,j Indicates j The fused features; By calculating the error between the predicted output and the actual output, the calibration loss function is obtained: （3） In the formula, L cal represents the calibration loss function, y real Indicates the actual output, y pred represents the predicted value; Using the gradient descent algorithm to minimize the calibration loss function, the formula for the updated digital twin model parameters is as follows: （4） In the formula, θ and θ ´ respectively represent the parameters of the digital twin model before and after the update, η represents the learning rate, ▽ θ L cal Represents the gradient of the calibration loss function with respect to the digital twin model parameters.

7. A digital twin simulation device for extracting underground salt water to prevent seawater intrusion, characterized in that: The digital twin simulation method for extracting underground salt water to prevent seawater intrusion according to any one of claims 1 to 6 is used to implement the physical simulation device, comprising a test sand box, wherein both ends of the test sand box are respectively connected to baffles with uniformly distributed holes, wherein the baffles divide the test sand box into a seawater chamber and a freshwater chamber located on both sides, and a test water chamber located in the middle, wherein both sides of the test water chamber are respectively connected to the seawater chamber and the freshwater chamber through holes arranged thereon, and further comprising: A constant head mechanism for maintaining the water level balance in the seawater chamber; A pumping mechanism for pumping water from the test water chamber; A pressure measuring mechanism for measuring the pressure of a test water chamber.

8. The digital twin simulation device for extracting underground salt water to prevent seawater intrusion according to claim 7 is characterized in that: The fixed water head mechanism includes a water tank and a water bucket. A baffle is fixedly connected inside the water tank. The baffle divides the water tank into an overflow tank and a fixed water tank. The seawater chamber is connected to the fixed water tank through a joint. The overflow tank is connected to the water bucket through a connecting pipe. A submersible pump is connected inside the water bucket. The submersible pump can pump the water in the bucket into the fixed water tank.

9. The digital twin simulation device for extracting underground salt water to prevent seawater intrusion according to claim 8 is characterized in that: A water stop plate for sealing the joint is slidably connected inside the joint, and the water stop plate is connected to the joint through a tension spring. The seawater chamber is connected to a fixed pipe, and a piston is slidably connected inside the fixed pipe. The piston is connected to a magnet that has an attractive effect on the water stop plate, and the magnetic force of the magnet is greater than the elastic force of the tension spring.

10. The digital twin simulation device for extracting underground salt water to prevent seawater intrusion according to claim 9 is characterized in that: A switch that can control the operation of the submersible pump is connected inside the fixed pipe, and the switch is located on one side of the piston. The piston is connected to the fixed pipe through a spring, and the piston is fixedly connected to a sleeve. The sleeve is threadedly connected to a screw, and the screw is connected to the magnet. The water stop plate is connected to a one-way valve that only allows water to flow from the fixed water tank into the seawater chamber.

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