CN219568718U - A simulation device for preventing and controlling seawater intrusion in multiphase aquifers - Google Patents

Abstract

The utility model discloses a simulation device for preventing and controlling seawater intrusion in a multiphase aquifer, which belongs to the technical field of experimental devices, and comprises a transparent box body, and the inner cavity of the box body is separated into a salt water box and a sand box arranged in sequence by a porous partition plate And the fresh water tank, the salt water inlet is opened on the left box plate of the salt water tank, and the fresh water inlet is opened on the right box plate of the fresh water tank; the simulated barrier, the simulated barrier includes a water injection well simulated pipe and/or a water barrier simulated slab and/or underground dam simulation slab; salt water constant head circulation device; fresh water constant head circulation device. The simulation device provided by the utility model obtains economical and practical hydraulic pressure by exploring the influence of the depth of the water barrier, the height of the underground dam, the distance between the water barrier and the underground dam, and the water injection position of the water injection well on the inhibition of seawater intrusion in the multiphase aquifer. Barrier and hybrid physical barrier construction options. The materials for the simulation device are easy to obtain and process, and the simulation accuracy of the actual site aquifer, seawater and freshwater is high.

Description

A simulation device for preventing and controlling seawater intrusion in multiphase aquifers

technical field

The utility model relates to a simulation device for preventing and controlling seawater intrusion in a multiphase aquifer, belonging to the technical field of experimental devices.

Background technique

Construction of hydraulic barriers and mixed physical barriers are important engineering measures to prevent seawater intrusion. Among them, the hydraulic barrier prevents seawater intrusion by raising the groundwater level, which is easy to operate and requires relatively little manpower and material resources. The mixed physical barrier is composed of an impervious partition wall and a semi-permeable underground dam. The mixed physical barrier has relatively low permeability and can prevent seawater intrusion by cutting off the seawater intrusion channel. When the water injection flow rate is the same, the location of the water injection is different, or the depth of the diaphragm wall, the height of the underground dam, and the distance between the diaphragm wall and the underground dam in the site will all lead to different effects of hydraulic barriers and mixed physical barriers in preventing seawater intrusion. Furthermore, the combined use of hydraulic barriers and mixed physical barriers can more effectively prevent seawater intrusion, but how to design the two measures to achieve the optimal prevention and control plan needs to be tried and verified.

As a physical model for simulating seawater intrusion, the sandbox device can obtain the optimal solution for preventing seawater intrusion by simulating various barriers. The traditional sandbox model is only filled with one medium, which cannot accurately describe the aquifer distribution of the actual site. In addition, the hydraulic pressure of the seawater and freshwater models established by the traditional sand box device deviates greatly from the actual situation, resulting in low simulation accuracy of the device.

The utility model aims to provide a device for simulating hydraulic barriers and mixed physical barriers to prevent and control seawater intrusion in multiphase aquifers to solve the deficiencies in the prior art.

It should be noted that the above content belongs to the scope of the inventor's technical cognition and does not necessarily constitute the prior art.

Utility model content

In order to solve the problems existing in the prior art, the utility model provides a simulation device for preventing and controlling seawater intrusion in multiphase aquifers. By exploring the depth of the water-retaining wall, the height of the underground dam, and the distance between the water-retaining wall and the underground dam, note that Effect of well injection location on inhibition of seawater intrusion in multiphase aquifers.

The utility model realizes above-mentioned object by taking following technical scheme:

A simulation device for preventing seawater intrusion in a multiphase aquifer, comprising:

Transparent box body, the inner cavity of the box body is divided into salt water tank, sand box and fresh water tank arranged in sequence from left to right by two porous partitions, and the holes on the porous partitions are attached with filter screen, the sand box is filled with a medium that simulates the lithology of the site formation, and several salt water inlets are opened on the left box plate of the salt water tank, and several salt water inlets are opened on the right box plate of the fresh water tank. fresh water inlet;

The simulated barrier includes a water injection well simulation pipe and/or a diaphragm wall simulation board and/or an underground dam simulation board, the lower end of the water injection well simulation pipe is inserted into the upper part of the sand box, and the underground dam simulation board The lower end is inserted into the bottom of the sand box, and the lower end of the water partition wall simulation board is inserted into the upper part of the sand box;

A salt water constant head circulation device, the salt water constant head circulation device communicates with the salt water inlet through a connecting pipe;

A fresh water constant water head circulation device, the fresh water constant water head circulation device communicates with the fresh water inlet through a connecting pipe.

Optionally, the simulation device for preventing and controlling seawater intrusion in multiphase aquifers provided by the utility model also includes two removable baffles, which can be blocked when the two baffles are attached to the two porous partitions The openings in the porous separator.

Optionally, the simulation device for preventing and controlling seawater intrusion in multiphase aquifers provided by the utility model also includes a pressure measuring device, the back side of the sand box is provided with a pressure measuring hole, and a filter screen is attached to the pressure measuring hole. , the pressure measuring device communicates with the pressure measuring hole through a connecting pipe.

In one of the embodiments, the pressure measuring device includes a plurality of transparent pressure measuring tubes, the pressure measuring tubes are vertically fixed on the mounting plate, and the mounting plate is provided with a scale bar, and the upper nozzle of each pressure measuring tube Open setting, the lower nozzle is connected with the corresponding pressure measuring hole through the connecting pipe.

In one of the embodiments, the salt water constant head circulation device includes a salt water storage tank, a salt water transfer box, a first partition is inserted in the salt water transfer box, and the top of the first partition is lower than the salt water transfer box. The top of the water transfer box, the first partition divides the salt water transfer box into two chambers, and the bottoms of the two chambers are respectively provided with a salt water supply port and a salt water return port, and the salt water supply port passes through The connecting pipe communicates with the salt water inlet of the salt water tank, and the salt water return port communicates with the salt water storage tank through the connecting pipe, and the salt water storage tank is also provided with salt water supply through the connection pipe through the salt water pump and the salt water transfer box The chambers of the mouth communicate.

In one embodiment, the fresh water constant head circulation device includes a first fresh water storage tank and a fresh water transfer box, a second partition is inserted in the fresh water transfer case, and the top of the second partition is lower than the fresh water transfer case. The second partition divides the fresh water transfer box into two chambers, and the bottom of the two chambers are respectively provided with a fresh water supply port and a fresh water return port, and the fresh water supply port is connected to the fresh water tank through a connecting pipe The inlet port is connected, the fresh water return port is connected to the first fresh water storage tank through the connecting pipe, and the first fresh water storage tank is also connected to the chamber with the fresh water supply port in the fresh water transfer box through the connecting pipe through the first fresh water pump.

Specifically, the upper end of the water injection well simulation pipe communicates with the second fresh water storage tank through the second fresh water pump through the connecting pipe.

In one embodiment, the medium in the flask includes coarse sand, fine sand, and silt from bottom to top.

Preferably, a grid of 1cm×1cm is drawn on the front panel of the sand box.

In one of the specific implementations, the sand box and the porous partition adopt plexiglass plates, the material of the filter screen is acrylic resin material, and the material of the water separation wall simulation board and the underground dam simulation board is acrylic resin material ;

The fresh water inlet, the salt water inlet, the fresh water supply port, the fresh water return port, the salt water supply port and the salt water return port are all provided with valves;

The salt water in the salt water tank is mixed with dyeing agent.

The beneficial effects of this application include but are not limited to:

In order to solve the above-mentioned technical problems, the utility model provides a simulation device for preventing and controlling seawater intrusion in multiphase aquifers by hydraulic barriers and mixed physical barriers. , the influence of the water injection position of the injection well on the inhibition of seawater intrusion in the multiphase aquifer, and the economical and practical hydraulic barrier and mixed physical barrier construction scheme are obtained to inhibit the seawater intrusion in the actual site. The materials for the simulation device are easy to obtain and process, and the simulation accuracy of the actual site aquifer, seawater and freshwater is high.

Description of drawings

The drawings described here are used to provide a further understanding of the application and constitute a part of the application. The schematic embodiments and descriptions of the application are used to explain the application and do not constitute an improper limitation to the application. In the attached picture:

Fig. 1 is the structural representation of the simulation device of preventing and controlling seawater intrusion in the multiphase aquifer provided by the utility model;

Fig. 2 is the schematic diagram of sand box and porous partition;

In the figure, 110, salt water tank; 111, salt water inlet; 120, sand box; 121, coarse sand; 122, fine sand; 123, silt; 124, pressure measuring hole; 130, fresh water tank; 131, fresh water inlet mouth;

200. Porous partition;

310, water injection well simulation pipe; 311, second fresh water storage tank; 320, water partition wall simulation board; 330, underground dam simulation board;

400. Salt water fixed head circulation device; 410. Salt water storage barrel; 420. Salt water transfer box; 430. First partition; 441. Salt water supply port; 442. Salt water return port;

500. Fresh water fixed water head circulation device; 510. First fresh water storage tank; 520. Fresh water transfer box; 530. Second partition; 541. Fresh water supply port; 542. Fresh water return port;

600, a pressure measuring device; 610, a pressure measuring tube; 620, a mounting plate; 630, a scale bar.

Detailed ways

In order to clearly illustrate the technical features of this solution, the utility model will be described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

It should be noted that many specific details are set forth in the following description in order to fully understand the utility model, however, the utility model can also be implemented in other ways different from those described here. Therefore, the protection scope of the present utility model is not limited by the specific embodiments disclosed below.

As shown in Figures 1 and 2, the simulation device for preventing and controlling seawater intrusion in multiphase aquifers provided by the utility model includes a transparent box, a salt water constant head circulation device, and a fresh water constant head circulation device.

Specifically, the inner cavity of the box body is divided into a salt water tank 110, a sand tank 120 and a fresh water tank 130 arranged in sequence from left to right by two porous partitions 200. The sand box 120 is filled with a medium simulating the lithology of the site formation, and a simulated barrier is inserted into the medium. In actual application, the sand box 120 is filled with medium according to the lithology of the site formation. Preferably, the medium in the sand box 120 includes coarse sand 121, fine sand 122, and silt sand 123 from bottom to top, which can be used to simulate multi-phase aquifers, making the simulation results more realistic, and overcoming the previous sand box models that only fill one medium, which cannot accurately describe the defects of the actual site aquifer distribution.

In the actual natural environment, in the salty and fresh water mixed area, due to the difference in density, the water flow is clearly stratified: the freshwater runoff with lower density is located in the upper layer and drains downward, and the seawater with higher density is in the lower layer. The interface generates shear force, and the shear force is balanced with the slope of the water, so that the salt water intrudes into the estuary in a wedge shape, that is, the salt water wedge. In the simulation device provided by the utility model, the salt water in the salt water tank 110 infiltrates into the sand box 120 to the right through the aperture on the porous partition, and the fresh water in the fresh water tank 130 infiltrates into the sand box 120 to the left through the aperture on the porous partition. , after the brackish-fresh water interface migrates to a steady state, the saltwater wedge is simulated.

The simulation barrier includes a water injection well simulation pipe 310 and/or a diaphragm wall simulation board 320 and/or an underground dam simulation board 330, the lower end of the water injection well simulation pipe 310 is inserted into the upper part of the sand box 120, and the lower end of the underground dam simulation board 330 is inserted into the At the bottom of the sand box 120 , the lower end of the water partition wall simulation board 320 is inserted into the upper part of the sand box 120 . When simulating a hydraulic barrier, a water injection well simulation pipe 310 is inserted into the sand box 120 . When one of the partition wall simulation board 320 and the underground dam simulation board 330 is selected to be inserted into the sand box 120, a single physical barrier is simulated, and when both are inserted simultaneously, a mixed physical barrier is simulated.

There are several salt water inlets 111 on the left box plate of the salt water tank 110, and the salt water constant head circulation device 400 is connected with the salt water inlets 111 through connecting pipes; Fresh water enters the port 131, and the fresh water constant water head circulation device 500 communicates with the fresh water inlet 131 through a connecting pipe. In this way, constant head water supply to the salt water tank 110 and the fresh water tank 130 is realized, and the simulation accuracy of sea water and fresh water is improved.

During the experiment, salt water needs to be injected into the salt water tank 110, fresh water is injected into the sand box 120, and after fresh water is injected into the fresh water tank 130, the hydraulic connection between the sand box 120, the salt water tank 110 and the fresh water tank 130 is opened. Therefore, in the process of injecting water into the salt water tank 110 , the sand tank 120 and the fresh water tank 130 , it is necessary to block the openings on the porous partition 200 and open the openings when hydraulic connection is established. In order to facilitate the above operations, in a preferred embodiment, the simulation device for preventing and controlling seawater intrusion in multiphase aquifers provided by the utility model also includes two removable baffles, and the two baffles are respectively attached to two The openings on the porous separator 200 can be blocked when it is placed on the porous separator 200. The baffle adopts an impermeable board body, such as an acrylic board.

Specifically, the salt water constant head circulation device 400 includes a salt water storage tank 410, a salt water transfer box 420, a first partition 430 is inserted in the salt water transfer box 420, and the top of the first partition 430 is lower than the salt water transfer box 420. On the top of the box 420, the first partition 430 divides the salt water transfer box 420 into two chambers, and the bottom of the two chambers is respectively provided with a salt water supply port 441 and a salt water return port 442, and the salt water supply port 441 passes through The connecting pipe communicates with the salt water inlet 111 of the salt water tank 110, the salt water return port 442 communicates with the salt water storage tank 410 through the connection tube, and the salt water storage tank 410 is also connected to the salt water transfer box 420 through the connection pipe through the salt water pump and the salt water transfer box 420. The chambers of the water supply port 441 communicate.

The fresh water fixed water head circulation device 500 includes a first fresh water storage tank 510, a fresh water transfer box 520, and a second partition 530 is inserted in the fresh water transfer box 520, and the top of the second partition 530 is lower than the top of the fresh water transfer box 520. Two partitions 530 divide the fresh water transfer box 520 into two chambers. The bottoms of the two chambers are respectively provided with a fresh water supply port 541 and a fresh water return port 542. The fresh water supply port 541 is connected to the fresh water inlet of the fresh water tank 130 through a connecting pipe. 131, the fresh water return port 542 communicates with the first fresh water storage tank 510 through the connecting pipe, and the first fresh water storage tank 510 also communicates with the chamber where the fresh water supply port 541 is set in the fresh water transfer box 520 through the connecting pipe through the first fresh water pump.

During operation, the first fresh water pump pumps the fresh water in the first fresh water storage tank 510 into the chamber where the fresh water supply port 541 is opened in the fresh water transfer box 520, and the salt water pump pumps the salt water in the salt water storage tank 410 into the salt water The transfer box 420 is provided with a salt water supply port 441 in the chamber. When the water level in the chamber where the fresh water supply port 541 is opened in the fresh water transfer box 520 reaches the top of the second partition 530, the re-entered water will overflow into the chamber where the fresh water return port 542 is opened, and then return to the first fresh water storage tank through the connecting pipe 510 in. In this way, a constant water level is formed in the chamber in which the fresh water water supply port 541 is opened in the fresh water transfer box 520, so as to realize constant water supply of fresh water. Similarly, the salt water in the salt water transfer box 420 also forms a constant water level, so as to realize the constant head water supply of salt water.

Further, the upper end of the water injection well simulation pipe 310 communicates with the second fresh water storage tank 311 through the connecting pipe through the second fresh water pump, and the water in the second fresh water storage tank 311 is injected into the water injection well simulation pipe 310 through the second fresh water pump.

Further, the simulation device for preventing and controlling seawater intrusion in multi-phase aquifers provided by the utility model also includes a pressure measuring device 600, the back side of the sand box 120 is provided with a pressure measuring hole 124, and a filter is attached to the pressure measuring hole 124. The pressure measuring device 600 communicates with the pressure measuring hole 124 through a connecting pipe.

In one specific embodiment, the pressure measuring device 600 includes a plurality of transparent pressure measuring tubes 610, the pressure measuring tubes 610 are vertically fixed on the mounting plate 620, and a scale bar 630 is attached on the mounting plate 620 close to the pressure measuring tubes 610, It is convenient to measure the liquid level in the pressure measuring tube 610. The upper nozzle of each pressure measuring tube 610 is open, and the lower nozzle is connected to the corresponding pressure measuring hole 124 through a connecting pipe.

The transfer box 420 in salt water and the transfer box 520 in fresh water are placed on the height-adjustable bracket. The water level of the transfer box 420 in salt water is consistent with that of the salt water tank 110. The height of the transfer box 520 is adjusted through the bracket.

Preferably, a grid of 1 cm×1 cm is drawn on the front box plate of the sand box 120, which is convenient for measuring the insertion depth and spacing distance of the water injection well simulation pipe 310, the water partition wall simulation plate 320, and the underground dam simulation plate 330.

Usually, valves are arranged on the fresh water inlet 131, the salt water inlet 111, the fresh water supply port 541, the fresh water return port 542, the salt water supply port 441, and the salt water return port 442, so as to control the timing of water intake.

Usually, the sand box 120 and the porous partition 200 are made of plexiglass, the filter screen is made of acrylic resin, the injection well simulation pipe 310 is made of acrylic pipe; the water partition wall simulation board 320 and the underground dam simulation board 330 are made of acrylic resin Material; the first partition 430 and the second partition 530 adopt acrylic board.

The connecting pipe adopts a rubber tube or a silicone tube. The first fresh water pump is a submersible pump, and the second fresh water pump is preferably a peristaltic pump.

The simulation device and working process provided by the utility model will be described below in the form of specific embodiments.

Example:

In this embodiment, the dimensions of the sand box 120 are: 1.4m in length, 0.1m in width, and 0.5m in height; the dimensions of the porous partition 200 are: 0.1m in length, 0.5m in height, and 0.01m in thickness.

The pressure measuring holes 124 provided on the back box plate of the sand box 120 are 5 rows and 10 columns, totally 50 holes.

The thicknesses of coarse sand, fine sand and silt sand are 18cm, 12cm and 15cm respectively.

The size of the transfer box 420 in salt water and the transfer box 520 in fresh water is: the length, width and height are all 30cm.

A valve is provided at a height of 20 cm on the right side of the fresh water tank 130; a valve is provided at a height of 20 cm on the left side of the salt water tank 110.

The height of the first partition 430 and the second partition 530 is 20 cm.

The water injection well simulation pipes 310 are 40 cm long, 1 cm in diameter, and 20 in number; the lower ends of the water injection well simulation pipes 310 are inserted into different depths of the sand box 120 to simulate the influence of different water injection positions on seawater intrusion.

Dividing wall simulation boards 320 and underground dam simulation boards 330 with heights of 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, 35 cm, and 40 cm were prepared.

The installation board 620 is made of PVC board, 1m long and 0.8m wide; 36 piezometer tubes 610 are fixed on the installation board 620, the piezometer tubes 610 are 1m long and 4mm in diameter; the measurable length of the scale bar 630 is 1m.

The salt water in the salt water tank 110 is a NaCl solution with a concentration of 25g/L, which is used to simulate seawater samples; a dye is mixed into the salt water with a concentration of 5g/L, which is convenient for observing the range of seawater intrusion. Specifically, the dyeing agent is carmine dyeing agent.

The working process of the simulation device provided in this embodiment is as follows:

(1) Insert the two baffles against the porous partition 200 into the sand box 120 respectively, so that the openings on the porous partition 200 are blocked, and then fill the sand box 120 with a medium, every 1-2 cm thick, Compact once;

(2) Slowly add water to the sand box 120, control the speed of adding water to prevent the medium from being washed up, and stop adding water when the water level of the sand box 120 reaches 41 cm;

(3) Utilize the first fresh water pump in the first fresh water storage barrel 510 to pump fresh water to the chamber where the fresh water transfer box 520 is provided with the fresh water supply port 541, open the valve on the fresh water inlet 131 and the fresh water supply port 541, and fresh water flows into Fresh water tank 130; open the valve on the fresh water return port 542, when the fresh water level in the chamber of the fresh water supply port 541 reaches the top of the second dividing plate 530, the fresh water pumped in will enter the chamber provided with the fresh water return port 542 , and then return to the fresh water storage tank through the connecting pipe, so as to realize the constant head water intake of the fresh water tank 130;

Utilize the salt water pump in the salt water storage tank 410 to pump the salt water into the salt water transfer box 420 and open the chamber with the salt water supply port 441, open the valves on the salt water inlet 111 and the salt water supply port 441, and the salt water flows into Salt water tank 110; open the valve on the salt water return port 442, when the salt water level in the chamber of the salt water supply port 441 reaches the top of the first partition 430, the salt water pumped in will enter the salt water The chamber of the water return port 442 is then returned to the salt water storage tank through the connecting pipe, so that the fixed water head of the salt water tank 110 can be fed into the water;

(4) pull out two baffle plates, make hydraulic connection between sand box 120 and salt water tank 110, fresh water tank 130, start to carry out simulation test, added carmine dyeing agent in salt water, is convenient to observe the situation of salt water intrusion;

(5) After the interface between salt water and fresh water migrated to a stable state, after recording the position of the salt water wedge front in the initial state, in the fresh water area, the horizontal direction of the salt water wedge front increased by 10cm, and the heights were 5cm, 15cm, and 25cm. , 35cm place, place the water injection well simulation pipe 310, the water injection flow rate of the water injection well simulation pipe 310 is 200ml/min;

When simulating a composite physical barrier, in the salt water wedge region in the medium of the sand box 120, a 40cm-high water partition wall simulation board 320 is inserted to a certain depth to simulate a water partition wall, and the depths of the water partition wall simulation board 320 inserted into the medium are respectively It is 20cm, 22cm, 24cm, 26cm, 28cm, 30cm, the underground dam simulation board 330 that height is 10cm, 15cm, 20cm, 25cm, 30cm, 35cm is inserted into the bottom of the sand box 120 to simulate the underground dam, the level of the water barrier and the underground dam The distances are 4cm, 5cm, 6cm, 7cm, 8cm, 9cm, 10cm.

After the injection well simulation pipe 310 injects water, the diaphragm wall simulation plate 320 and the underground dam simulation plate 330 are inserted, the brackish-fresh water interface reaches a new stable state. At this time, the position of the salt water wedge front arrives is recorded, and compared with the salt water in the initial state For the position of the wedge front, calculate the seawater intrusion regression coefficient (R), which characterizes the repelling degree of the saltwater wedge, which is the effectiveness of hydraulic barriers and mixed physical barriers in preventing seawater intrusion. Calculate R under the above scenarios separately, and the scenario with the largest R is the optimal position and height of hydraulic barriers and mixed physical barriers to prevent seawater intrusion.

The rollback factor (R) is:

In the formula: L ₀ —the distance from the front of the salt water wedge to the coastline under the initial stable condition;

L—the distance from the front of the saltwater wedge to the coastline when the hydraulic barrier and the mixed physical barrier are set up and stabilized again.

In this way, by using the simulation device provided by the utility model, by setting different simulation situations, specifically, by setting water injection wells in different positions, water partition walls with different depths, underground dams with different heights, and water partition walls with different distances from the underground Dam, looking for the optimal solution of hydraulic barrier and mixed physical barrier to prevent seawater intrusion. Carrying out this simulation before the actual construction of prevention and control measures can verify that the constructed physical barriers can effectively prevent seawater intrusion.

In describing the present invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal" , "Top", "Bottom", "Inner", "Outer", "Axial", "Radial", "Circumferential" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, It is only for the convenience of describing the present invention and simplifying the description, but does not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

In this utility model, unless otherwise clearly specified and limited, terms such as "installation", "communication", "connection" and "fixation" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connection, or integration; it can be mechanical connection, electrical connection, or communication; it can be direct communication, or indirect communication through an intermediary, and it can be the internal communication of two components or the interaction of two components relation. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present utility model according to specific situations.

The above-mentioned specific implementation manners cannot be used as limitations on the protection scope of the present utility model. For those skilled in the art, any substitution, improvement or transformation made to the implementation manners of the present utility model shall fall within the protection scope of the utility model.

The parts of the utility model that are not described in detail are the known techniques of those skilled in the art.

Claims (10)

1. An analog device for controlling seawater intrusion in a multiphase aquifer, comprising:

the device comprises a transparent box body, wherein the inner cavity of the box body is divided into a salty water tank, a sand box and a fresh water tank which are sequentially arranged from left to right through two porous partition boards, a filter screen is attached to an orifice of the porous partition boards, a medium simulating the lithology of a ground stratum is filled in the sand box, a plurality of salty water inlet ports are formed in a left box plate of the salty water tank, and a plurality of fresh water inlet ports are formed in a right box plate of the fresh water tank;

the simulation barrier comprises a water injection well simulation pipe and/or a water-proof wall simulation plate and/or an underground dam simulation plate, wherein the lower end of the water injection well simulation pipe is inserted into the upper part of the sand box, the lower end of the underground dam simulation plate is inserted into the bottom of the sand box, and the lower end of the water-proof wall simulation plate is inserted into the upper part of the sand box;

the brine fixed head circulation device is communicated with the brine inlet through a connecting pipe;

the fresh water constant head circulation device is communicated with the fresh water inlet through a connecting pipe.

2. A simulation device for controlling seawater intrusion in a multiphase aquifer according to claim 1 further comprising two removable baffles capable of sealing the apertures in the porous barrier when the two baffles are respectively in contact with the two porous barriers.

3. The simulator for preventing and treating seawater intrusion in a multiphase aquifer of claim 1, further comprising a pressure measuring device, wherein a pressure measuring hole is formed in a back box plate of the sand box, a filter screen is attached to the pressure measuring hole, and the pressure measuring device is communicated with the pressure measuring hole through a connecting pipe.

4. A simulation device for preventing and controlling seawater intrusion in a multiphase aquifer according to claim 3, wherein the pressure measuring device comprises a plurality of transparent pressure measuring tubes, the pressure measuring tubes are vertically fixed on a mounting plate, scale bars are arranged on the mounting plate, and an upper tube orifice and a lower tube orifice of each pressure measuring tube are arranged in an open manner and are connected with corresponding pressure measuring holes through connecting tubes.

5. The simulation device for preventing and controlling seawater invasion in a multiphase aquifer according to claim 1, wherein the brine fixed head circulation device comprises a brine storage barrel and a brine transfer box, a first partition plate is inserted in the brine transfer box, the top of the first partition plate is lower than the top of the brine transfer box, the first partition plate divides the brine transfer box into two chambers, a brine water supply port and a brine water return port are respectively formed in the bottoms of the two chambers, the brine water supply port is communicated with a brine inlet of the brine tank through a connecting pipe, the brine water return port is communicated with the brine storage barrel through a connecting pipe, and the brine storage barrel is further communicated with a chamber in which the brine water supply port is formed in the brine transfer box through a brine pump through a connecting pipe.

6. The simulation device for preventing and controlling seawater invasion in a multiphase aquifer according to claim 1, wherein the fresh water fixed head circulation device comprises a first fresh water storage barrel and a fresh water transfer box, a second partition plate is inserted in the fresh water transfer box, the top of the second partition plate is lower than the top of the fresh water transfer box, the second partition plate divides the fresh water transfer box into two chambers, a fresh water supply port and a fresh water return port are respectively formed in the bottoms of the two chambers, the fresh water supply port is communicated with a fresh water inlet of the fresh water tank through a connecting pipe, the fresh water return port is communicated with the first fresh water storage barrel through the connecting pipe, and the first fresh water storage barrel is further communicated with a chamber provided with the fresh water supply port through the first fresh water pump and the fresh water transfer box through the connecting pipe.

7. The simulation device for preventing and controlling seawater intrusion in a multiphase aquifer according to claim 1, wherein the upper end of the water injection well simulation pipe is communicated with the second fresh water storage bucket through a second fresh water pump by a connecting pipe.

8. A simulation device for controlling seawater intrusion in a multiphase aquifer according to claim 1, wherein the medium in the flask comprises coarse sand, fine sand, silt from bottom to top.

9. A simulation apparatus for controlling seawater intrusion in a multiphase aquifer according to claim 1, wherein a grid of 1cm x 1cm is drawn on the frontal plate of the flask.

10. The simulation device for preventing and controlling seawater intrusion in a multiphase aquifer according to claim 1, wherein the sand box and the porous partition plate are made of organic glass plates, the filter screen is made of acrylic resin materials, and the waterproof wall simulation plate and the underground dam simulation plate are made of acrylic resin materials;

the fresh water inlet, the salt water inlet, the fresh water supply port, the fresh water return port, the salt water supply port and the salt water return port are all provided with valves;

and a coloring agent is mixed in the salty water tank.