A coastal groundwater-surface water monitoring and sampling device adaptive to tidal fluctuation and experimental method thereof

Abstract

The application discloses a kind of coastal groundwater-surface water monitoring sampling device and experimental method of adaptation tidal fluctuation, including carrying platform, amphibious mobile track system located below carrying platform, positioning navigation system located on carrying platform, buoyancy adjusting wing plate system symmetrically located on the both sides of carrying platform, groundwater monitoring sampling system located on carrying platform, surface water monitoring sampling system located on carrying platform, sample separation and preservation system located in carrying platform, visual monitoring system located on carrying platform and control system located in carrying platform, wherein control system is respectively electrically connected with amphibious mobile track system, positioning navigation system, buoyancy adjusting wing plate system, groundwater monitoring sampling system, surface water monitoring sampling system, sample separation and preservation system and visual monitoring system.The application realizes synchronous, layered sampling of groundwater and surface water at different sites in coastal zone within full tidal cycle.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering technology, and in particular to a coastal groundwater-surface water monitoring and sampling device and its experimental method that are adapted to tidal fluctuations. Background Technology

[0002] The coastal zone is the area where land and ocean interact most intensely, and tides are a key driving force controlling the exchange of groundwater and surface water and the transport of materials within the coastal zone. With the rapid industrialization and urbanization of coastal areas, the problem of land-based pollutants entering the ocean through groundwater flows is becoming increasingly prominent. Accurate monitoring of the hydrodynamic exchange processes between groundwater and surface water in the coastal zone and the spatiotemporal distribution patterns of pollutants is of significant scientific value and practical importance for coastal water resource protection, ecological restoration, and sustainable development.

[0003] However, the coastal environment is extremely complex. The same location can experience drastically different states with tidal fluctuations, such as exposed mudflats, partial submersion, and complete submersion, posing a significant challenge to monitoring. Currently, monitoring of coastal groundwater and surface water mainly relies on fixed monitoring wells and manual sampling methods. While fixed monitoring wells allow for long-term observation, they only reflect single-point conditions and are insufficient to characterize the spatial heterogeneity of coastal groundwater and surface water. Furthermore, they are costly to construct and difficult to maintain. Although manual sampling allows for multi-point sampling, it requires substantial manpower and resources and is limited by tidal cycles. Staff must arrive at sampling points during specific tidal periods, making it difficult to conduct simultaneous multi-point sampling within the optimal time window and accurately characterize the dynamic process of groundwater-surface water exchange under tidal influence. In addition, manual sampling poses safety risks in silty tidal flats and deeper water areas, and its sampling efficiency is low with poor data representativeness.

[0004] Existing mobile monitoring or sampling equipment has limited functionality: unmanned monitoring vessels (CN120942496A, CN119459984A) cannot adapt to water level changes caused by tides and cannot operate on exposed mudflats after the tide recedes; while ordinary tracked sampling devices (CN106769213A) are prone to sinking on soft silty beaches, and once submerged by the rising tide, they often cannot continue to work. Summary of the Invention

[0005] Purpose of the invention: The first purpose of this invention is to provide a coastal groundwater-surface water monitoring and sampling device that adapts to tidal fluctuations. This invention can achieve mobile monitoring and sampling at different locations in the coastal zone under tidal fluctuation conditions, and can also maintain a stable sampling depth at different tidal levels.

[0006] The second objective of this invention is to provide an experimental method for a coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations, which enables synchronous and stratified sampling of groundwater and surface water at different locations in the coastal zone throughout the entire tidal cycle, and quantitatively inverts the groundwater-surface water exchange flux based on the monitoring data.

[0007] Technical Solution: To achieve the above objectives, the present invention provides a coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations, comprising a transport platform, an amphibious mobile tracked system located below the transport platform, a positioning and navigation system located on the transport platform, a buoyancy adjustment wing plate system symmetrically located on both sides of the transport platform, a groundwater monitoring and sampling system located on the transport platform, a surface water monitoring and sampling system located on the transport platform, a sample separation and preservation system located within the transport platform, a visual monitoring system located on the transport platform, and a control system located within the transport platform. The control system is electrically connected to the amphibious mobile tracked system, the positioning and navigation system, the buoyancy adjustment wing plate system, the groundwater monitoring and sampling system, the surface water monitoring and sampling system, the sample separation and preservation system, and the visual monitoring system.

[0008] Optionally, the transport platform includes a box that is divided into a power compartment, a control compartment, and a sample compartment from bottom to top by a waterproof partition, and the power compartment is equipped with multiple lithium battery packs.

[0009] Optionally, the amphibious mobile tracked system includes a left drive unit and a right drive unit with identical structures and symmetrical arrangement, and adaptive webbed tracks respectively wound around the left drive unit and the right drive unit. The left drive unit and the right drive unit respectively include a waterproof servo motor fixed to the bottom of the transport platform, a planetary reduction gearbox connected to the output shaft of the waterproof servo motor, a drive wheel connected to the output shaft of the planetary reduction gearbox, and a driven wheel fixed to the bottom of the transport platform via a fixed shaft. The adaptive webbed tracks are wound around the drive wheel and the driven wheel. The outer surface of the adaptive webbed tracks is provided with webbed grooves spaced longitudinally. Retractable webbed propulsion plates are installed in the webbed grooves via torsion spring hinges.

[0010] Optionally, the positioning and navigation system includes an RTK-GPS module located at the top of the carrier platform, an inertial navigation unit located inside the carrier platform, and a depth sensor located at the bottom of the carrier platform, wherein the RTK-GPS module, the inertial navigation unit, and the depth sensor are electrically connected to the main controller.

[0011] Optionally, the buoyancy adjustment wing plate system includes a hinged base fixed to the side of the transport platform, a rectangular metal frame hinged to the hinged base, a limiting traction steel wire rope with one end connected to the side wall of the transport platform and the other end connected to the rectangular metal frame, a straight bracket located in the middle of the rectangular metal frame, a retractable airbag fixed to the straight bracket, an air pump located inside the transport platform, an air pipe with a two-way air valve, and a magnetic locking device located above the side wall of the transport platform for storing the vertical rectangular metal frame.

[0012] Optionally, the groundwater monitoring and sampling system includes a horizontal installation platform fixed to the transport platform, a multi-section telescopic electric push rod fixed to the horizontal installation platform and capable of vertical extension and retraction, a pore water inlet tube located at the telescopic end of the multi-section telescopic electric push rod, a pore water inlet located at the end of the pore water inlet tube, a stainless steel filter screen covering the outside of the pore water inlet and filled with a quartz sand filter element, and a flexible thin tube connected to the pore water inlet, extending from the top of the pore water inlet tube, laid along the outside of the multi-section telescopic electric push rod, passing through the transport platform, and connected to the sample separation and preservation system.

[0013] Optionally, the surface water monitoring and sampling system includes a protective net fixed to the upper front end of the transport platform, a short inlet pipe located on the protective net and passing through the transport platform and connected to the sample separation and preservation system, and a one-way check valve located on the short inlet pipe.

[0014] Optionally, the sample separation and preservation system includes a first multi-channel peristaltic pump connected to a surface water monitoring and sampling system via a silicone hose, a second multi-channel peristaltic pump connected to a groundwater monitoring and sampling system via a silicone hose, a first electric three-way valve array connected to the first multi-channel peristaltic pump, a second electric three-way valve array connected to the second multi-channel peristaltic pump, a first sample collection tray connected to the first electric three-way valve array, a second sample collection tray connected to the second electric three-way valve array, and a waste liquid discharge outlet connected to the first and second electric three-way valve arrays. The first sample collection tray is provided with multiple surface water sample bottles, and the second sample collection tray is provided with multiple groundwater sample bottles.

[0015] Optionally, the visual monitoring system includes LED lights located on the front face and left and right sides of the transport platform, a rotating camera located on the front face of the transport platform, and an image transmission module located inside the transport platform.

[0016] The control system includes a human-machine interface controller and a main controller, a data acquisition unit, a wireless communication module, a first servo driver, a second servo driver, a third servo driver, a fourth servo driver, a fifth servo driver, and a sixth servo driver located in the transport platform. The main controller is connected to each servo driver, the image transmission module, the data acquisition unit, and the wireless communication module via a CAN bus.

[0017] The main controller controls the movement of the left and right tracks of the amphibious mobile tracked system through the first and second servo drives respectively; the main controller controls the buoyancy adjustment wing plate system to adjust buoyancy through the third servo drive; the main controller controls the groundwater monitoring and sampling system to perform sampling through the fourth servo drive; the main controller controls the sample separation and preservation system to perform surface water sample separation and preservation through the fifth servo drive; and the main controller controls the sample separation and preservation system to perform groundwater sample separation and preservation through the sixth servo drive.

[0018] The experimental method for a coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations, as described in this invention, includes the following steps: After the sampling device reaches the target area of ​​the coastal zone and enters the water, the depth sensor of the positioning and navigation system detects the water depth data and transmits it to the main controller of the control system. The main controller determines that it is in underwater mode. The webbed propulsion plates of the amphibious mobile track system unfold into a vertical state under the action of the torsion spring return force. When the track rotates, the webbed propulsion plates push the water to generate thrust and realize underwater maneuvering. The target suspension depth is set through the human-machine interface controller. According to the deviation between the actual depth fed back by the depth sensor and the target depth, the main controller adjusts the inflation and deflation of the retractable airbag in real time to make the device stably suspend at the target suspension depth. Surface moisture sampling based on tidal time series was first performed by setting up a first sample collection tray. Several surface water sample bottles, numbered as follows: Set on the second sample collection tray Each groundwater sample bottle is numbered. ,in The number is consistent with the number of key hydrodynamic stages within the tidal half-cycle; For the During the second sampling, once the tide reaches the target stage and the device stabilizes underwater, the second sampling is initiated via the human-machine interface controller. In the second surface water sampling, the main controller first controls the first electric three-way valve array via the fifth servo driver. The three-way valve of the channel is switched to the waste discharge direction, and the first multi-channel peristaltic pump is started to extract water samples for pipeline flushing, expelling residual air and previous residual water samples from the waste liquid outlet; after flushing, the three-way valve is switched to the collection direction, and surface water is sampled by the surface water monitoring and sampling system, and finally injected into the surface water sample bottle at the corresponding position on the first sample collection tray; when the injected volume reaches the target volume, the main controller stops the first multi-channel peristaltic pump and closes the three-way valve, completing the surface water sample collection at this depth; during sampling, the main controller reads the current reading of the depth sensor and records it. This value represents the actual water depth of the surface water cover device at that moment. After each surface water sampling, the device performs time-series synchronous sampling at the same location, achieving synchronous paired sampling of groundwater and surface water; for the first... In the second sampling, the main controller, via the fourth servo driver, controls the pore water inlet of the groundwater monitoring and sampling system to extend downwards to the groundwater sampling depth. To conduct groundwater sampling, the main controller starts the second multi-channel peristaltic pump. The groundwater sample first passes through the second electric three-way valve array... The three-way valve in the channel is used to flush the pipeline, and then the flow direction is switched to the collection direction. The groundwater sample of the target volume is injected into the groundwater sample bottle on the second sample collection tray, and the sampling is completed. During each surface water and groundwater sample collection process, the main controller synchronously records the sampling time. Sampling location Surface water depth Surface water sample bottle number and groundwater sample bottle number And it is stored in the main controller in the form of structured data packets; Quantitative inversion of tidal-driven groundwater-surface water exchange flux was performed based on time-series paired sampling data. First, sample bottles were retrieved and sent to the laboratory for salinity and water quality parameter analysis. The salinity analysis results of the surface water sample bottles were recorded as follows: The salinity analysis results of groundwater sample bottle 7061-i are recorded as follows: Combined with sampling time and surface water depth Obtain time-series paired dataset ; Obtaining aquifer porosity Aquifer control volume terrestrial freshwater background salinity Sediment permeability coefficient and mass transfer coefficient , Utilizing surface water depth By calculating the tidal-driven groundwater flux through the rate of tidal level change, the instantaneous tidal-driven water flux can be directly estimated. and subscript Represents the direction in which seawater enters the tidal flat during high tide; subscript This indicates the direction in which water flows out of the lower aquifer of the tidal flat during low tide. First, according to the records Calculate the average tide level within the monitoring period using individual tide level and water depth data: , Then, based on Darcy's law, the first The vertical Darcy flow velocity at the sediment-water interface at each sampling time point is: , in The sediment permeability coefficient, This refers to the groundwater sampling depth. The head difference that drives the seepage; The instantaneous volumetric water flux driven by tides is obtained by multiplying the seepage velocity by the exchange interface area. , in The area of ​​the interface between surface water and groundwater within the monitoring range of the device; according to The positive and negative signs distinguish the direction of seepage: when Right now During high tide, seawater seeps into the aquifer, resulting in an instantaneous water flux. , ; when Right now During low tide, the aquifer water is discharged, thus obtaining the instantaneous water flux. , ; Quantify the total volume and salt exchange flux of groundwater-surface water in the coastal zone, and determine the depth below the monitoring point of the device. The aquifer within the specified range is defined as the control volume. According to the principle of solute mass conservation, the dynamic change of groundwater salinity within the control volume is controlled by the following processes: tidal-driven seawater infiltration carries surface water salts into the aquifer, and tidal-driven groundwater discharge carries aquifer salts out of the aquifer. The mathematical expression of the continuity equation is: , The physical meaning is: terrestrial groundwater discharge flux Carrying concentration Fresh water is introduced into the control volume, while an equal volume of water with a concentration of [missing information] is introduced. The water from the aquifer is pushed out, and the net effect is to dilute the salt content of the aquifer. In the time intervals , The above continuous equation is discretized using the forward difference method: , Discharge flux of terrestrial groundwater Quantitative inversion was performed to obtain the terrestrial groundwater discharge flux. Then calculate the total salt exchange flux between groundwater and surface water in each time period. The calculation formula is: .

[0019] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The present invention provides foldable webbed propulsion plates on the surface of the track and uses the spring force of torsion springs to realize the automatic retraction and extension of the webbed plates. This allows the same track to provide traction on the mudflats and propulsion underwater, without the need for additional propellers. This greatly simplifies the structure, reduces costs and failure rates, and achieves amphibious mobility. (2) The present invention controls the deployment and retraction of the wing plate by inflating and deflating the airbag. In the mudflat mode, the wing plate is deployed to increase the ground area and prevent sinking into the mud. In the underwater mode, the buoyancy of the airbag is used to achieve precise depth control. One set of mechanisms solves the two problems of preventing sinking and constant depth suspension at the same time. (3) The present invention can operate continuously in three states: low tide exposed mudflats, shallow intertidal zone and high tide deep water. By adapting to different tide levels through the buoyancy adjustment system, it can continuously monitor and sample the same location throughout the entire tidal cycle to obtain complete tidal process data. (4) The present invention is equipped with both a groundwater sampling system and a surface water sampling system, which can simultaneously collect groundwater and overlying surface water samples at different depths at the same location and at the same time, and obtain complete profile data of the groundwater-surface water exchange interface, providing a data basis for quantitative inversion of groundwater-surface water exchange flux. (5) Through the visual monitoring system and human-computer interaction controller, the operator can remotely control the device to operate in dangerous intertidal zones and deep water areas from a safe position on the shore, avoiding the safety risks of manual wading sampling. It is especially suitable for high-risk environments such as silty tidal flats, high flow velocity, and deep water. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the bottom cross-section of the present invention; Figure 3 This is a partial enlarged view of the amphibious mobile tracked system of the present invention; Figure 4 This is a diagram of the power compartment of the present invention; Figure 5 This is a diagram of the control cabin of the present invention; Figure 6 This is a schematic diagram of the sample separation and preservation system of the present invention; Figure 7 This is a schematic diagram of the groundwater monitoring and sampling system of the present invention; The transport platform 1, power compartment 101, lithium battery pack 1011, inverter 1012, wires 1013, control compartment 102, and sample compartment 103 are all included. Amphibious mobile tracked system 2, left drive unit 201, right drive unit 202, adaptive webbed track 203, waterproof servo motor 2011, planetary reduction gearbox 2012, drive wheel 2013, fixed shaft 2014, driven wheel 2015, webbed groove 2031, torsion spring hinge 2032, webbed propulsion plate 2033, arc-shaped baffle 2034; Positioning and navigation system 3, RTK-GPS module 301, inertial navigation unit 302, depth sensor 303; 4. Buoyancy adjustment wing plate system, 401. Hinged base, 402. Rectangular metal frame, 402. Stainless steel rotating shaft, 402. Limiting traction steel wire rope, 403. I-shaped bracket, 404. Circular mounting hole, 404. Retractable airbag, 405. Inflation pump, 406. Air pipe, 4061. Two-way air valve, 407. Magnetic locking device, 408. 5. Groundwater monitoring and sampling system, 501. Horizontal installation platform, 502. Multi-section telescopic electric push rod, 503. Pore water inlet, 503. Stainless steel filter screen, 5031. Quartz sand filter element, 5032. Flexible fine tube, 504. Surface water monitoring and sampling system 6, stainless steel protective mesh cover 601, inlet short pipe 602, one-way check valve 603; Sample separation and preservation system 7, first multi-channel peristaltic pump 701, second multi-channel peristaltic pump 702, first electric three-way valve array 703, second electric three-way valve array 704, first sample collection tray 705, surface water sample bottle 7051, second sample collection tray 706, groundwater sample bottle 7061, silicone tubing 707, waste liquid discharge outlet 708; Visual monitoring system 8, LED lighting 801, rotating camera 802, image transmission module 803; Control system 9, main controller 901, data acquisition unit 902, wireless communication module 903, first servo driver 904, second servo driver 905, third servo driver 906, fourth servo driver 907, fifth servo driver 908, sixth servo driver 909, human-machine interaction controller 9010. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0022] like Figures 1 to 7 As shown, the present invention provides a coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations, comprising a transport platform 1, an amphibious mobile tracked system 2, a positioning and navigation system 3, a buoyancy adjustment wing plate system 4, a groundwater monitoring and sampling system 5, a surface water monitoring and sampling system 6, a sample separation and preservation system 7, a visual monitoring system 8, and a control system 9.

[0023] like Figure 4 As shown, the main body of the transport platform 1 is a pressure-resistant, sealed stainless steel box structure. The box is placed vertically and has external dimensions of 1500mm (length) × 700mm (width) × 600mm (height). The interior of the box is divided into a power compartment 101, a control compartment 102, and a sample compartment 103 by three layers of waterproof partitions. The power compartment 101 is located at the bottom of the transport platform box, with a height of 200mm, and houses three lithium battery packs 1011, an inverter 1012, and multiple electrical wires 1013. The lithium battery packs 1011 use lithium iron phosphate batteries and power the entire device through the inverter 1012 and the multiple electrical wires 1013.

[0024] like Figure 5As shown, the control cabin 102 is located in the middle of the transport platform housing, with a height of 150mm. It houses the main controller 901, data acquisition unit 902, wireless communication module 903, first servo driver 904, second servo driver 905, third servo driver 906, fourth servo driver 907, fifth servo driver 908, sixth servo driver 909, inertial navigation unit 302, image transmission module 803, and air pump 406. The main controller 901 is an embedded industrial computer, fixed in the control cabin 102, and connected to each servo driver, inertial navigation unit 302, image transmission module 803, data acquisition unit 902, and wireless communication module 903 via a CAN bus. Waterproof cable perforations are provided on the side wall of the control cabin 102, and the perforations are sealed with waterproof connectors. The sample chamber 103 is located at the top of the transport platform housing, with a height of 250mm. It houses the sample separation and preservation system 7, first sample collection tray 705, and second sample collection tray 706. The sample collection trays all adopt a stainless steel frame structure, and each sample collection tray can hold 6 surface water sample bottles 7051 and groundwater sample bottles 7061. The top of the sample chamber 103 is equipped with a cover for easy replacement of sample bottles after sampling.

[0025] like Figure 2 and Figure 3 As shown, the amphibious mobile tracked system 2 is located at the bottom of the transport platform 1 and consists of a left drive unit 201, a right drive unit 202, and two adaptive webbed tracks 203. The left drive unit 201 and the right drive unit 202 are structurally identical and independent, each containing a waterproof servo motor 2011, a planetary reduction gearbox 2012, a drive wheel 2013, a fixed shaft 2014, and a driven wheel 2015. The waterproof servo motor 2011 is a DC brushless motor with a waterproof and corrosion-resistant casing. The output shaft of the planetary reduction gearbox 2012 is connected to the drive wheel 2013 to transmit torque. The driven wheel 2015 is mounted on the bottom of the transport platform 1 via the fixed shaft 2014. Both the drive wheel 2013 and the driven wheel 2015 have a diameter of 200mm and toothed grooves on their surfaces to mesh with the tracks. The adaptive webbed tracks 203 have a total length of 300mm and a width of 150mm and are fitted onto the drive wheel 2013 and the driven wheel 2015. The track body is made of seawater-resistant neoprene rubber. A web-like groove 2031 is formed every 400mm longitudinally along the track surface. A foldable web-like propulsion plate 2033 is mounted within the web-like groove 2031 via a torsion spring hinge 2032. The web-like propulsion plate 2033 is made of corrosion-resistant glass fiber reinforced nylon, with streamlined edges to reduce water resistance. The torsion spring hinge 2032 is made of stainless steel torsion spring, ensuring that the web-like propulsion plate 2033 remains in a 90-degree perpendicular unfolded position to the track surface when no external force is applied. An arc-shaped baffle 2034 is installed on the outer side of the drive sprocket 2013. The curvature of the baffle perfectly matches the outer circumference of the drive sprocket 2013. The baffle is made of stainless steel plate with a thickness of 3mm.

[0026] The positioning and navigation system 3 consists of a high-precision RTK-GPS module 301, an inertial navigation unit 302, and a depth sensor 303. The high-precision RTK-GPS module 301 is installed inside a transparent waterproof cover at the center of the top of the transport platform 1. The RTK-GPS module 301 is connected to the main controller 901, transmitting latitude, longitude, and UTC time data in real time. The inertial navigation unit 302 is installed inside the control cabin 102 and connected to the main controller 901 via a bus. It measures the device's attitude angles (pitch angle, roll angle, yaw angle), acceleration, and angular velocity, providing feedback for motion control. The depth sensor 303 is a pressure-type depth gauge, installed at the center of the bottom of the transport platform 1. The depth sensor 303 calculates water depth using pressure values, and the signal from the depth sensor 303 is acquired by the data acquisition unit 902 and transmitted to the main controller 901.

[0027] The buoyancy adjustment wing plate system 4 is symmetrically installed on the left and right side walls of the transport platform 1, and consists of a hinged base 401, a rectangular metal frame 402, a limiting traction steel wire rope 403, a straight bracket 404, a retractable airbag 405, an air pump 406, a two-way air valve 407, and a magnetic locking device 408. The structures on the left and right sides are identical, achieving symmetrical buoyancy adjustment. The hinged base 401 is made of stainless steel sheet welded into an L-shaped structure and is fixed to the outer surface of the side wall of the transport platform 1. The rectangular metal frame 402 is made of hollow aluminum alloy square tube welded together, with an external dimension of 1500mm in length × 700mm in width, a square tube cross-section of 20mm × 20mm, and a wall thickness of 2mm. One long side of the rectangular metal frame 402 is connected to the hinged base 401 through a stainless steel pivot 4021, and the two ends of the pivot are supported by bearing seats to ensure flexible rotation of the frame. A straight bracket 404 is welded inside the rectangular metal frame 402. The two ends of the straight bracket 404 are fixedly connected to the middle of the two long sides of the rectangular metal frame 402 by welding. Two circular mounting holes 4041 are provided on the straight bracket 404. The retractable airbag 405 is a cylindrical rubber airbag made of neoprene rubber. The two retractable airbags 405 are fixed in the two mounting holes 4041 of the straight bracket 404, with the airbag axis perpendicular to the frame plane. Two air pumps 406 are installed inside the control cabin 102 and connected to the retractable airbags 405 and the two-way air valve 407 respectively via air pipes 4061. The air pipes 4061 are made of polyurethane hoses. The air pipes 4061 extend from the control cabin 102 and connect to the four airbags on the left and right side wing panels respectively. A two-way air valve 407 is installed in the air pipe 4061 circuit. When the main controller 901 issues an air intake or exhaust command, the two-way air valve 407 opens, and gas passes through the two-way air valve 407 and enters or exits the retractable airbag 405 through the inflation pump 406. The main controller 901 controls the start and stop of the inflation pump 406 and the opening and closing of the two-way air valve 407 through the third servo driver 906. A magnetic locking device 408 is installed on the upper part of the outer surface of the side wall of the transport platform 1 (corresponding to the upper frame position of the rectangular metal frame 402 when it is vertically stored) to adsorb and fix the rectangular metal frame 402 in the stored state. One end of the limiting traction steel wire rope 403 is fixed to the outer long side of the rectangular metal frame 402 away from the rotating axis, and the other end is connected to the upper part of the side wall of the transport platform 1. The maximum release length of the limiting traction wire rope 403 is set such that when the rectangular metal frame 402 is flipped down and unfolded to be perpendicular to the side wall of the transport platform 1 at 90 degrees (i.e., in a horizontal state), the wire rope is just taut, forming a suspension limiting structure similar to a suspension bridge.When the device needs to deploy the wing panels, the main controller 901 controls the air pump 406 to inflate the retractable airbag 405. The airbag expands and presses against the side wall of the transport platform 1, generating an outward thrust to overcome the attraction force of the magnetic locking device 408. When the magnetic attraction force weakens and breaks due to displacement, the rectangular metal frame 402 flips downward around the pivot 4021 under its own gravity until it is taut and suspended in the horizontal deployment position by the limiting traction steel cable 403.

[0028] like Figure 7 As shown, the groundwater monitoring and sampling system 5 is installed above the tail of the transport platform 1 and consists of a horizontal installation platform 501, a multi-section telescopic electric actuator 502, a pore water inlet 503, and a flexible capillary tube 504. The horizontal installation platform 501 is a rectangular steel plate structure. It is fixed to the tail of the transport platform 1, with its surface placed horizontally. The multi-section telescopic electric actuator 502 is a four-section electric actuator, consisting of four sleeve-type telescopic rods, each 350mm long. The total length of the actuator is 350mm when fully retracted and 1400mm when fully extended. The first fixed section of the multi-section telescopic electric actuator 502 is fixed to the upper surface of the horizontal installation platform 501, with its axis perpendicular to the plane of the platform and its extension direction vertically downwards. The fourth section, the thinnest telescopic section, is located below the horizontal installation platform 501 and extends downwards away from it. The pore water inlet 503 of the pore water inlet tube is located at the tip of the fourth section, the thinnest of the multi-section telescopic electric push rod 502. The outside of the pore water inlet 503 is covered with a 200-mesh stainless steel filter screen 5031, forming a rectangular filter screen cover with a height of 25mm. This cover effectively filters out sediment particles while allowing pore water to enter freely. The inside of the filter screen is filled with a quartz sand filter element 5032 to further intercept fine particles. The push rod motor power cable is connected to the fourth servo driver 907 of the main controller 901 via a waterproof connector. The pore water inlet 503 is connected to a flexible thin tube 504. The flexible thin tube 504 extends from the top of the pore water inlet tube and runs along the outside of the multi-section telescopic electric push rod 502. It is secured to the outer wall of the push rod with several plastic cable ties to prevent the flexible thin tube from sagging or tangling during the extension and retraction of the push rod. The flexible capillary tube 504 passes through a pre-drilled hole in the tail frame of the transport platform 1, enters the interior of the transport platform 1, and runs along the internal wiring channel to the sample chamber 103. Finally, it connects to the second multi-channel peristaltic pump 702 inside the sample chamber 103 via a silicone hose 707. The flexible capillary tube 504 has sufficient slack within the extension range of the push rod and is laid in an S-shaped serpentine manner to ensure that the capillary tube is not stretched when the push rod is fully extended and does not accumulate excessively when the push rod is fully retracted.

[0029] The surface water monitoring and sampling system 6 is fixed to the upper front end of the transport platform 1 and consists of a stainless steel protective mesh cover 601, a short inlet pipe 602, and a one-way check valve 603. The stainless steel protective mesh cover 601 is hemispherical, 130mm in diameter, with a wire diameter of 0.8mm, and is made of stainless steel. The protective mesh cover 601 is fixed to a pre-drilled mounting hole on the front face of the transport platform 1. The short inlet pipe 602 is made of stainless steel, with an inner diameter of 10mm, an outer diameter of 14mm, and a length of 80mm. One end of the short inlet pipe 602 is located in the center inside the protective mesh cover 601, and the other end passes through the front wall of the transport platform 1, with the perforation sealed by a waterproof quick-connect fitting. Inside the platform, the short inlet pipe 602 is connected to the first multi-channel peristaltic pump 701 inside the sample chamber 103 via a silicone hose 707. The one-way check valve 603 is installed inside the short inlet pipe 602, and its valve core uses a silicone rubber spherical structure.

[0030] like Figure 6As shown, the sample separation and preservation system 7 is installed inside the sample chamber 103 of the transport platform and consists of a first multi-channel peristaltic pump 701, a second multi-channel peristaltic pump 702, a first electric three-way valve array 703, a second electric three-way valve array 704, a first sample collection tray 705, a second sample collection tray 706, a silicone hose 707, and a waste liquid discharge outlet 708. The first multi-channel peristaltic pump 701 uses a 6-channel peristaltic pump head, and its input end is connected to the inlet pipe 602 of the surface water monitoring and sampling system 6 via the silicone hose 707. The second multi-channel peristaltic pump 702 uses a 6-channel peristaltic pump head with the same specifications as the first multi-channel peristaltic pump 701. Its input end is connected to the flexible thin tube 504 of the groundwater monitoring and sampling system 5 via the silicone hose 707. The output ends of the first multi-channel peristaltic pump 701 and the second multi-channel peristaltic pump 702 are both connected to six silicone hoses 707, each corresponding to an electric three-way valve. The first electric three-way valve array 703 and the second electric three-way valve array 704 each consist of six electric three-way valves, each with one inlet and two outlets: a waste outlet and a collection outlet. The waste liquid outlet 708 is a common outlet formed by converging the waste outlets of the twelve three-way valves, passing through the side wall of the sample chamber 103 and leading to the outside of the transport platform 1. The first sample collection tray 705 and the second sample collection tray 706 are both stainless steel trays with six regularly arranged circular grooves on their surface. The first sample collection tray 705 is used to hold surface water sample bottles 7051, and the second sample collection tray 706 is used to hold groundwater sample bottles 7061. The sample bottles are made of polyethylene, with screw caps for sealing the bottle opening. The collection port of the electric three-way valve is connected to the corresponding sample vial via a silicone tubing 707, with the end of the tubing extending into the bottom of the vial. The main controller 901 controls the start / stop and speed of each channel of the first multi-channel peristaltic pump 701 via the fifth servo driver 908, and simultaneously controls the corresponding three-way valve to switch the flow path direction; the main controller 901 controls the start / stop and speed of each channel of the second multi-channel peristaltic pump 702 via the sixth servo driver 909, and simultaneously controls the corresponding three-way valve to switch the flow path direction.

[0031] The visual monitoring system 8 consists of LED lights 801, a rotating camera 802, and an image transmission module 803. Three LED lights 801 are installed on the front face and left and right sides of the transport platform 1, respectively. The LED lights 801 are controlled by the main controller 901. The rotating camera 802 is installed in the center of the front face of the transport platform 1. The camera housing is a stainless steel pressure-resistant cover, and the front of the cover has a tempered glass transparent window. The camera has a 360° continuous horizontal rotation range and a pitch range of -45° to +45°. The image transmission module 803 uses digital wireless image transmission technology and is installed inside the control cabin 102, connected to the rotating camera 802 via a cable. The image transmission receiver is integrated into the human-machine interface controller 9010, and the receiver outputs an HDMI signal to the controller's display screen.

[0032] The control system 9 includes a main controller 901, a data acquisition unit 902, a wireless communication module 903, a first servo driver 904, a second servo driver 905, a third servo driver 906, a fourth servo driver 907, a fifth servo driver 908, a sixth servo driver 909, and a human-machine interface controller 9010. The main controller 901 is an embedded industrial computer. It connects to the first to sixth servo drivers via a CAN bus, to the sensors of the positioning and navigation system 3 via a serial port, and to the wireless communication module 903 via an Ethernet port. The data acquisition unit 902 connects to the main controller 901 via an I2C bus. The data acquisition unit 902 is used to acquire analog signals such as those from the depth sensor 303 and battery voltage. The wireless communication module 903 is a wireless communication module connected to the main controller 901 via an Ethernet connection. The human-machine interface controller 9010 is a handheld remote control terminal equipped with a color touchscreen display. The human-machine interface controller 9010 has a built-in wireless transceiver module, which is paired with the wireless communication module 903 of the main controller 901. The human-computer interaction controller 9010 also integrates an image transmission and receiving module to receive real-time images from the rotating camera 802 and display them on the screen.

[0033] An experimental method for a coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations, according to the present invention, includes the following steps: (1) When the sampling device reaches the target area of ​​the coastal zone, the power is turned on through the human-machine interaction controller 9010, the main controller 901 performs a system self-test to confirm that the sampling device is working normally; the RTK-GPS module 301 obtains the current position coordinates, the inertial navigation unit 302 completes attitude initialization, and the depth sensor 303 calibrates the zero point; the visual monitoring system 8 is started, and the surrounding environment is observed through the human-machine interaction controller 9010. (2) The human-machine interface controller 9010 sends a movement command. The main controller 901 controls the waterproof servo motors 2011 on the left and right sides to drive the adaptive webbed track 203 through the first servo driver 904 and the second servo driver 905, so as to realize the device's forward, backward and turning movements. When the device walks on hard ground or tidal flats, the webbed propulsion plate 2033 is pressed into the webbed groove 2031 by the ground reaction force, and the outer surface of the track remains flat, relying on friction to provide traction. When the device enters the soft silt area, the buoyancy adjustment wing plate system 4 is activated. The main controller 901 controls the air pump 406 to inflate the retractable airbag 405 through the third servo driver 906. The rectangular metal frame 402 unfolds from the vertical state to the horizontal state, increasing the ground area and preventing the device from sinking. The device moves to the predetermined sampling point position according to GPS navigation. (3) When the device enters the water body, the depth sensor 303 detects the water depth data and transmits it to the main controller 901. The main controller 901 determines that it is in underwater mode. The webbed propulsion plate 2033 unfolds into a vertical state under the action of the torsion spring. When the track rotates, the webbed propulsion plate 2033 pushes the water body to generate thrust and realize underwater maneuvering. The target suspension depth is set by the human-machine interaction controller 9010. According to the deviation between the actual depth fed back by the depth sensor 303 and the target depth, the inflation and deflation of the retractable airbag 405 is adjusted in real time to make the device stably suspend at the target suspension depth and prepare for surface water sampling. (4) Surface water sampling is carried out based on tidal time series. First, six surface water sample bottles 7051 are set on the first sample collection tray 705, which are numbered SW-1, SW-2, SW-3, SW-4, SW-5 and SW-6 respectively. Six groundwater sample bottles 7061 are set on the second sample collection tray 706, which are numbered GW-1, GW-2, GW-3, GW-4, GW-5 and GW-6 respectively. The design of six sample vials is based on the following scientific considerations: In coastal areas of my country, the tidal pattern is predominantly semi-diurnal, with a complete high-low tidal half-cycle lasting approximately 6.2 hours. To fully characterize the dynamic process of groundwater-surface water exchange driven by tides, it is necessary to cover six key hydrodynamic stages within the tidal half-cycle, collecting a pair of synchronous samples of surface water and groundwater at each stage; the six sampling time points evenly divide the half-tidal cycle into five time intervals. The mathematical constraints satisfy the minimum of 5 independent equations required for solving the subsequent discretized mass conservation equation; the temporal correspondence between the 6 surface water sample bottles and the tidal phase is shown in Table 1, where, ; Table 1. Correspondence between 6 surface water sampling bottles and tidal phases

[0034] For the i-th sampling, When the tide reaches the target stage, and the device stabilizes underwater, the operator initiates the i-th surface water sampling via the human-machine interface controller 9010. The specific steps are as follows: Pipeline flushing: The main controller 901 controls the three-way valve of the i-th channel in the first electric three-way valve array 703 to switch to the waste discharge direction through the sixth servo driver 909, and starts the first multi-channel peristaltic pump 701 to draw water sample at a flow rate of 100mL / min for pipeline flushing for 30 seconds, so that the residual air and the previous residual water sample are discharged from the waste liquid outlet 708 to ensure that the current sample is not cross-contaminated.

[0035] Formal Sampling: After rinsing, the three-way valve is switched to the collection direction, and the pump flow rate is reduced to 50 mL / min; the water sample flows sequentially through the stainless steel protective mesh cover 601, the inlet short pipe 602, the one-way check valve 603, and the silicone hose 707, and is finally injected into the surface water sample bottle 7051-i at the corresponding position on the first sample collection tray 705; when the injected volume reaches 200 mL, the main controller 901 stops the first multi-channel peristaltic pump 701 and closes the three-way valve, completing the surface water sample collection at this depth; Depth recording: During sampling, the main controller 901 reads the current reading of the depth sensor 303 and records it as... This value is the actual water depth of the surface water cover device at that moment, which directly reflects the tide level. If it is necessary to collect surface water profile samples at different depths at the same time, step (3) can be repeated after the above operation to adjust the suspension depth and inject the water sample into the reserved spare bottle position.

[0036] (5) After each surface water sampling is completed, the device immediately performs time-synchronous sampling at the same site to achieve synchronous pairing of groundwater and surface water sampling. For the i-th sampling, the main controller 901 sends an extension command to the multi-section telescopic electric push rod 502 through the fourth servo driver 907. The push rod extends vertically downward, driving the pore water inlet 503 to penetrate into the sediment to a depth of about 700 mm. After the push rod stops, the pore water enters the pore water inlet 503 after double filtration through the stainless steel filter screen 5031 and the quartz sand filter element 5032. The main controller 901 starts the second multi-channel peristaltic pump 702. The water sample flows through the flexible thin tube 504 and the silicone hose 707. First, it flushes the pipeline for 30 seconds through the i-th channel three-way valve of the second electric three-way valve array 704. Then, it switches to the collection direction and injects 200 mL of groundwater sample into the groundwater sample bottle 7061-i on the second sample collection tray 706. After the sampling is completed, the push rod retracts and resets.

[0037] Groundwater sampling depth in this invention Fixed parameters for the device design, The depth was determined based on the typical thickness of the active exchange layer of shallow pore water in the intertidal zone of coastal my country. All six groundwater samples were taken at the same depth to ensure the spatial comparability of concentration data at different tidal stages. The correspondence between the six groundwater sample bottles and the sampling time is shown in Table 2.

[0038] Table 2. Correspondence between 6 groundwater sample bottles and sampling time

[0039] (6) During each surface water and groundwater sample collection process, the main controller 901 synchronously records the sampling time. Sampling location The data, including surface water depth, surface water sample bottle number, and groundwater sample bottle number, are stored in the memory of the main controller 901 in the form of structured data packets and uploaded to the cloud server via the wireless communication module 903. Each sample bottle corresponds to a specific sample bottle, ensuring seamless integration of subsequent laboratory analysis data with on-site sensor data. The sampling time... This refers to the UTC time recorded by the RTK-GPS module 301, representing the absolute time of the i-th sample, used to calculate the time interval. As a time variable in the formula Discrete values; sampling positions This refers to the latitude and longitude coordinates recorded by the RTK-GPS module 301, representing the spatial coordinates of the device at the i-th sampling point, used to confirm that all 6 samplings were conducted at the same monitoring station; surface water depth. This refers to the depth data recorded by the depth sensor 303, representing the tidal depth at the i-th sampling point, used to calculate the rate of tidal level change. Used to estimate tidal-driven flux and Surface water sample bottle number Corresponding sample vial 7051-i, used for obtaining samples after laboratory analysis. Groundwater sample bottle number Corresponding sample vial 7061-i, used for obtaining samples after laboratory analysis. ; (7) Quantitative inversion of tidal-driven groundwater-surface water exchange flux based on time-series paired sampling data, specifically including the following steps: (7.1) Twelve sample bottles were retrieved, including six surface water sample bottles and six groundwater sample bottles, and sent to the laboratory for water quality parameter analysis. Taking salinity as an example, the laboratory analysis results are assigned as follows: The salinity analysis results of surface water sample bottle SW-i are denoted as The salinity analysis results of the groundwater sample bottle GW-i are recorded as follows: Unit: g / L; combined with sampling time and surface water depth Obtain time-series paired dataset ; (7.2) Obtaining the porosity of the aquifer Aquifer control volume terrestrial freshwater background salinity Sediment permeability coefficient and mass transfer coefficient , Among them, the porosity of the aquifer Sediment samples collected on-site can be analyzed in a laboratory, or values ​​can be obtained by referring to existing geological survey data for the area. Typical silty mudflats... ; Aquifer control volume The calculation formula is: , in The area of ​​the interface between surface water and groundwater within the monitoring range of the device, in m², can be estimated based on the projected area of ​​the device or the sampling influence radius; This refers to the groundwater sampling depth. ; Background salinity of terrestrial freshwater This represents the background salinity of terrestrial freshwater, and is typically a constant value close to 0. Sediment permeability The permeability coefficient of the coastal aquifer, in m / s, is obtained through the following methods: determining the permeability of sediment cores collected in the field using constant or variable head permeability tests in the laboratory; or referring to existing hydrogeological survey data and literature values ​​of similar sediments in the area. This parameter is used in step (7.3) to estimate the tidal-driven instantaneous water flux based on Darcy's law. Mass transfer coefficient The effective mass transfer coefficient at the sediment-water interface characterizes the proportion of cross-interface transport caused by hydrodynamic changes; it is obtained through laboratory measurements or by referring to literature values ​​of similar coastal sediments.

[0040] (7.3) The surface water depth continuously recorded by the depth sensor 303 in step (6) By calculating the tidal-driven groundwater flux through the rate of tidal level change, the instantaneous tidal-driven water flux can be directly estimated. and The subscript "in" represents the direction of seawater entering the tidal flat during high tide, and the subscript "out" represents the direction of water discharge from the lower aquifer of the tidal flat during low tide. The specific steps to establish the relationship between sensor data and formula parameters are as follows: First, calculate the average tide level during the monitoring period based on the six tide level and water depth data recorded in step (6): , Then, based on Darcy's law, the vertical Darcy flow velocity at the sediment-water interface at the nth sampling time point is: , in The sediment permeability coefficient, This refers to the groundwater sampling depth. , The head difference that drives the seepage; The instantaneous volumetric water flux driven by tides is obtained by multiplying the seepage velocity by the exchange interface area. The unit is m³ / s: , in The area of ​​the interface between surface water and groundwater within the monitoring range of the device, in m². according to The positive and negative signs distinguish the direction of seepage: when Right now During high tide, seawater seeps into the aquifer, resulting in an instantaneous water flux. , ; when Right now During low tide, the aquifer water is discharged, thus obtaining the instantaneous water flux. , ; (7.4) Quantify the total water volume and salt exchange flux of coastal groundwater-surface water, and determine the depth below the monitoring point of the device. The aquifer within the specified range is defined as the control volume. According to the principle of solute mass conservation, the dynamic change of groundwater salinity within the control volume is controlled by the following processes: tidal-driven seawater infiltration carries surface water salts into the aquifer, and tidal-driven groundwater discharge carries aquifer salts out of the aquifer. The mathematical expression of the continuity equation is: , The physical meaning is: terrestrial groundwater discharge flux Carrying concentration Fresh water is introduced into the control volume, while an equal volume of water with a concentration of [missing information] is introduced. The water from the aquifer is pushed out, and the net effect is the dilution of the aquifer salinity; when At that time, this item was simplified to ; In the i-th time interval , The above continuous equation is discretized using the forward difference method: , Terrestrial groundwater discharge flux (i.e., the terrestrial freshwater component of SGD discharged from the seabed) is a key groundwater flux that is extremely difficult to measure directly in coastal hydrogeological research; after discretizing the six sets of time-series paired data obtained in this invention with the above-mentioned mass conservation equation, it is possible to achieve... Quantitative inversion; Obtaining terrestrial groundwater discharge flux Then, the total salt exchange flux between groundwater and surface water was further calculated for each time period. The calculation formula is: , The above method is also applicable to other water quality parameters (dissolved oxygen, nutrient concentration, etc.), and the laboratory analysis results need to be replaced with the corresponding values. and The value is sufficient.

[0041] This device and implementation method enable precise quantification of water-salt exchange flux in the coastal zone, providing a scientific basis for coastal ecological environment protection and groundwater resource management.

Claims

1. A coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations, characterized in that, The system includes a transport platform (1), an amphibious mobile tracked system (2) located below the transport platform (1), a positioning and navigation system (3) located on the transport platform (1), a buoyancy adjustment wing plate system (4) symmetrically located on both sides of the transport platform (1), a groundwater monitoring and sampling system (5) located on the transport platform (1), a surface water monitoring and sampling system (6) located on the transport platform (1), a sample separation and preservation system (7) located inside the transport platform (1), a visual monitoring system (8) located on the transport platform (1), and a control system (9) located inside the transport platform (1). The control system (9) is electrically connected to the amphibious mobile tracked system (2), the positioning and navigation system (3), the buoyancy adjustment wing plate system (4), the groundwater monitoring and sampling system (5), the surface water monitoring and sampling system (6), the sample separation and preservation system (7), and the visual monitoring system (8), respectively.

2. The coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations according to claim 1, characterized in that, The transport platform (1) includes a box that is divided into a power compartment (101), a control compartment (102) and a sample compartment (103) from bottom to top by a waterproof partition. The power compartment (101) is equipped with multiple sets of lithium battery packs (1011).

3. The coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations according to claim 1, characterized in that, The amphibious mobile tracked system (2) includes a left drive unit (201) and a right drive unit (202) with identical structures and symmetrical arrangement, and adaptive webbed tracks (203) respectively wound around the left drive unit (201) and the right drive unit (202). The left drive unit (201) and the right drive unit (202) respectively include a waterproof servo motor (2011) fixed to the bottom of the transport platform (1), a planetary reduction gearbox (2012) connected to the output shaft of the waterproof servo motor (2011), and a... The planetary reduction gearbox (2012) has a drive wheel (2013) connected to its output shaft and a driven wheel (2015) fixed to the bottom of the transport platform (1) via a fixed shaft (2014). The adaptive webbed track (203) is wound around the drive wheel (2013) and the driven wheel (2015). The outer surface of the adaptive webbed track (203) is provided with webbed grooves (2031) spaced longitudinally. A retractable webbed propulsion plate (2033) is installed in the webbed groove (2031) via a torsion spring hinge (2032).

4. The coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations according to claim 1, characterized in that, The positioning and navigation system (3) includes an RTK-GPS module (301) located on the top of the carrier platform, an inertial navigation unit (302) located inside the carrier platform (1), and a depth sensor (303) located at the bottom of the carrier platform. The RTK-GPS module (301), the inertial navigation unit (302), and the depth sensor (303) are electrically connected to the main controller (901).

5. The coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations according to claim 1, characterized in that, The buoyancy adjustment wing plate system (4) includes a hinged base (401) fixed to the side of the transport platform, a rectangular metal frame (402) hinged to the hinged base (401), a limiting traction steel wire rope (403) with one end connected to the side wall of the transport platform and the other end connected to the rectangular metal frame (402), a straight bracket (404) located in the middle of the rectangular metal frame (402), a retractable airbag (405) fixed on the straight bracket (404), an air pump (406) located in the transport platform (1), an air pipe (4061) with a two-way air valve (407), and a magnetic locking device located above the side wall of the transport platform for storing the vertical rectangular metal frame (402).

6. The coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations according to claim 1, characterized in that, The groundwater monitoring and sampling system (5) includes a horizontal installation platform (501) fixed to the transport platform, a multi-section telescopic electric push rod (502) fixed on the horizontal installation platform (501) and capable of vertical extension and retraction, a pore water inlet pipe located at the telescopic end of the multi-section telescopic electric push rod (502), a pore water inlet (503) located at the end of the pore water inlet pipe, a stainless steel filter screen (5031) covering the outside of the pore water inlet (503) and filled with a quartz sand filter element (5032), and a flexible thin tube (504) connected to the pore water inlet, extending from the top of the pore water inlet pipe, laid along the outside of the multi-section telescopic electric push rod, and passing through the transport platform to connect with the sample separation and preservation system (7).

7. The coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations according to claim 1, characterized in that, The surface water monitoring and sampling system (6) includes a protective net cover (601) fixed to the upper front end of the transport platform (1), a short water inlet pipe (602) located on the protective net cover (601) and connected to the sample separation and preservation system (7) through the transport platform, and a one-way check valve (603) located on the short water inlet pipe (602).

8. The coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations according to claim 1, characterized in that, The sample separation and preservation system (7) includes a first multi-channel peristaltic pump (701) connected to the surface water monitoring and sampling system (6) via a silicone hose (707), a second multi-channel peristaltic pump (702) connected to the groundwater monitoring and sampling system (5) via a silicone hose (707), a first electric three-way valve array (703) connected to the first multi-channel peristaltic pump (701), a second electric three-way valve array (704) connected to the second multi-channel peristaltic pump (702), a first sample collection tray (705) connected to the first electric three-way valve array (703), a second sample collection tray (706) connected to the second electric three-way valve array (704), and a waste liquid discharge outlet (708) connected to the first electric three-way valve array (703) and the second electric three-way valve array (704). The first sample collection tray (705) is provided with multiple surface water sample bottles (7051), and the second sample collection tray (706) is provided with multiple groundwater sample bottles (7061).

9. The coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations according to claim 1, characterized in that, The visual monitoring system (8) includes LED lights (801) located on the front face and left and right sides of the carrier platform (1), a rotating camera (802) located on the front face of the carrier platform (1), and an image transmission module (803) located inside the carrier platform (1). The control system (9) includes a human-machine interaction controller (9010) and a main controller (901), a data acquisition unit (902), a wireless communication module (903), a first servo driver (904), a second servo driver (905), a third servo driver (906), a fourth servo driver (907), a fifth servo driver (908), and a sixth servo driver (909) located in the carrier platform (1). The main controller (901) is connected to each servo driver, the image transmission module (803), the data acquisition unit (902), and the wireless communication module (903) respectively via a CAN bus. The main controller (901) controls the movement of the left and right tracks of the amphibious mobile tracked system (2) through the first servo driver (904) and the second servo driver (905), respectively; the main controller (901) controls the buoyancy adjustment wing plate system (4) to adjust buoyancy through the third servo driver (906); the main controller (901) controls the groundwater monitoring and sampling system (5) to sample through the fourth servo driver (907); the main controller (901) controls the sample separation and preservation system (7) to separate and preserve surface water samples through the fifth servo driver (908); the main controller (901) controls the sample separation and preservation system (7) to separate and preserve groundwater samples through the sixth servo driver (909).

10. An experimental method for a coastal groundwater-surface water monitoring and sampling device adapted to tidal fluctuations, characterized in that, Includes the following steps: After the sampling device reaches the target area of ​​the coastal zone and enters the water, the depth sensor (303) of the positioning and navigation system (3) detects the water depth data and transmits it to the main controller (901) of the control system (9). The main controller (901) determines that it is in underwater mode. The webbed propulsion plate (2033) of the amphibious mobile track system (2) unfolds into a vertical state under the action of the torsion spring return force. When the track rotates, the webbed propulsion plate (2033) pushes the water to generate thrust and realizes underwater maneuvering. The target suspension depth is set by the human-machine interaction controller (9010). According to the deviation between the actual depth fed back by the depth sensor (303) and the target depth, the main controller (901) adjusts the inflation and deflation of the retractable airbag (405) in real time to make the device stably suspend at the target suspension depth. When sampling surface moisture based on tidal time series, first set up the first sample collection tray (705) Several surface water sample bottles, numbered as follows: Set on the second sample collection tray (706) Several groundwater sample bottles, each numbered... ,in The number is consistent with the number of key hydrodynamic stages within the tidal half-cycle; For the During the second sampling, once the tide reaches the target stage and the device stabilizes underwater, the second sampling is initiated via the human-machine interface controller (9010). In the second surface water sampling, the main controller (901) first controls the first electric three-way valve array (703) through the fifth servo driver (908). The three-way valve of the channel is switched to the waste discharge direction, and the first multi-channel peristaltic pump (701) is started to draw water samples for pipeline flushing, and the residual air and the previous residual water sample are discharged from the waste liquid discharge port (708). After rinsing, the three-way valve is switched to the collection direction. Surface water is sampled by the surface water monitoring and sampling system (6) and finally injected into the surface water sample bottle at the corresponding position on the first sample collection tray (705). When the injected volume reaches the target volume, the main controller (901) stops the first multi-channel peristaltic pump (701) and closes the three-way valve to complete the surface water sample collection at this depth. During sampling, the main controller (901) reads the current reading of the depth sensor (303) and records it as... This value represents the actual water depth of the surface water cover device at that moment. After each surface water sampling, the device performs time-series synchronous sampling at the same location, achieving synchronous paired sampling of groundwater and surface water; for the first... In the second sampling, the main controller (901) controls the pore water inlet (503) of the groundwater monitoring and sampling system (5) to extend downward to the groundwater sampling depth via the fourth servo driver (907). To perform groundwater sampling, the main controller (901) starts the second multi-channel peristaltic pump (702). The groundwater sample first passes through the second electric three-way valve array (704). The three-way valve in the channel is used to flush the pipeline, and then the flow direction is switched to the collection direction. The groundwater sample of the target volume is injected into the groundwater sample bottle on the second sample collection tray (706) and the sampling is completed. During each surface water and groundwater sample collection process, the main controller (901) synchronously records the sampling time. Sampling location Surface water depth Surface water sample bottle number and groundwater sample bottle number And stored in the main controller (901) in the form of structured data packets; Quantitative inversion of tidal-driven groundwater-surface water exchange flux was performed based on time-series paired sampling data. First, sample bottles were retrieved and sent to the laboratory for salinity and water quality parameter analysis. The salinity analysis results of the surface water sample bottles were recorded as follows: The salinity analysis results of groundwater sample bottle 7061-i are recorded as follows: Combined with sampling time and surface water depth Obtain time-series paired dataset ; Obtaining aquifer porosity Aquifer control volume terrestrial freshwater background salinity Sediment permeability coefficient and mass transfer coefficient , Utilizing surface water depth By calculating the tidal-driven groundwater flux through the rate of tidal level change, the instantaneous tidal-driven water flux can be directly estimated. and subscript Represents the direction in which seawater enters the tidal flat during high tide; subscript This indicates the direction in which water flows out of the lower aquifer of the tidal flat during low tide. First, according to the records Calculate the average tide level within the monitoring period using individual tide level and water depth data: ， Then, based on Darcy's law, the first The vertical Darcy flow velocity at the sediment-water interface at each sampling time point is: ， in The sediment permeability coefficient, This refers to the groundwater sampling depth. The head difference that drives the seepage; The instantaneous volumetric water flux driven by tides is obtained by multiplying the seepage velocity by the exchange interface area. ， in The area of ​​the interface between surface water and groundwater within the monitoring range of the device; according to The positive and negative signs distinguish the direction of seepage: when Right now During high tide, seawater seeps into the aquifer, resulting in an instantaneous water flux. ， ； when Right now During low tide, the aquifer water is discharged, thus obtaining the instantaneous water flux. ， ； Quantify the total volume and salt exchange flux of groundwater-surface water in the coastal zone, and determine the depth below the monitoring point of the device. The aquifer within the specified range is defined as the control volume. According to the principle of solute mass conservation, the dynamic change of groundwater salinity within the control volume is controlled by the following processes: tidal-driven seawater infiltration carries surface water salts into the aquifer, and tidal-driven groundwater discharge carries aquifer salts out of the aquifer. The mathematical expression of the continuity equation is: ， The physical meaning is: terrestrial groundwater discharge flux Carrying concentration Fresh water is introduced into the control volume, while an equal volume of water with a concentration of [missing information] is introduced. The water from the aquifer is pushed out, and the net effect is to dilute the salt content of the aquifer. In the time intervals , The above continuous equation is discretized using the forward difference method: ， Discharge flux of terrestrial groundwater Quantitative inversion was performed to obtain the terrestrial groundwater discharge flux. Then calculate the total salt exchange flux between groundwater and surface water in each time period. The calculation formula is: 。

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