A soil column device for pollutant migration in plastic concrete and its test method

Abstract

The invention discloses a pollutant migration soil column device for plastic concrete and a test method thereof. It belongs to the field of geotechnical test technology; air is compressed by a compressor and enters a gas storage tank, and high-pressure gas passes through an air filter; an electrical proportional valve is controlled by inputting an electrical signal to realize the control of the output air pressure; the regulated air pressure is input into a gas-liquid conversion device to realize the conversion of air pressure to hydraulic pressure; the upper part of the liquid-contaminated liquid conversion device contains polluted liquid, and the lower part is connected to the gas-liquid conversion device to realize the conversion of oil to polluted liquid; the polluted liquid concentration preparation device is provided with a pure solvent, a low-concentration solution storage tank, and a high-concentration solution storage tank, and the preparation of any pollutant concentration is realized by the control of a flow pump; the upper part of the soil column shower device is connected to the polluted liquid, the plastic concrete soil sample is contained in the soil column, and the lower part is connected to a pressure difference sensor and a liquid storage chamber; the invention realizes the migration of pollutants in plastic concrete under different water heads (especially high water heads and extremely high water heads).

Description

Technical Field

[0001] The present invention belongs to the field of geotechnical testing technology, and relates to a pollutant migration soil column device for plastic concrete and a test method thereof, and in particular, to a pollutant migration test in plastic concrete (soil or concrete with a very low permeability coefficient), and more particularly to a pollutant migration test device under different water heads (high water heads or extremely high water heads), which can explore the migration laws of pollutants under different high water heads. Background Art

[0002] Anti-pollution barriers are set up at the bottom and around the solid waste landfill to prevent the infiltration and diffusion of leachate from polluting the surrounding groundwater and soil. Plastic concrete, as a commonly used anti-pollution barrier material, has been used in the management of solid waste landfills. The migration of pollutants in the anti-pollution barrier is affected by various physical, chemical and biological reactions. It is a complex process, including convection, molecular diffusion, mechanical dispersion, adsorption, dissolution, precipitation and other effects. Usually, when evaluating the service performance of the anti-pollution barrier, the migration of pollutants is simplified to the problem of convection, diffusion and adsorption of pollutants. In order to obtain the convection, diffusion and adsorption parameters of pollutants in the anti-pollution barrier material, the commonly used method is to use indoor tests. Soil column test is an effective method to obtain the above parameters. Since the permeability coefficient of the plastic concrete anti-pollution barrier is very low, the migration speed of pollutants in it is very slow. The conventional soil column shower test uses a Marsh flask as a constant water head method, which can no longer meet the requirements of the test. In order to quickly and accurately obtain the parameters of pollutants in the plastic concrete anti-pollution barrier, a device that can stably provide a constant higher water head is required. At the same time, in order to explore the migration of pollutants in plastic concrete under different higher water heads, it is necessary to independently control the upstream water head and conduct multiple groups of tests at the same time.

[0003] At present, in domestic pollutant migration tests, few people have explored the migration of pollutants in extremely low permeability specimens (plastic concrete or concrete) under extremely high water heads. There is a lack of test equipment to explore the migration of pollutants in extremely low permeability specimens under extremely high water heads, and there is a lack of test instruments specifically for plastic concrete. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a soil column device for the migration of pollutants in plastic concrete and a test method thereof, which uses an air compressor, an air storage tank, an electrical proportional valve and an air-liquid conversion tank to achieve high-precision intelligent control of the upstream water head of the soil column shower device and provide extremely high water head pressure, and explore the migration of pollutants in plastic concrete under different water heads (including extremely high water heads). At the same time, a sensor is used downstream of the soil column device to monitor the changes in the shower liquid in real time.

[0005] Technical solution: The present invention provides a soil column device for pollutant migration in plastic concrete.

[0006] It includes an air supply device, an air pressure control device, an air-liquid conversion device, a liquid-contaminated liquid conversion device, a contaminated liquid concentration adjustment device, a soil column shower device and an effluent liquid storage monitoring device;

[0007] The air supply device comprises an air compressor (1) and an air storage tank (3), wherein interconnected high-pressure air pipes are installed on the air compressor (1) and the air storage tank (3), and a variable diameter adapter (2) is installed between the interconnected high-pressure air pipes;

[0008] A vent pipe (25) is installed at the output end of the gas storage tank (3); the other end of the vent pipe (25) is connected to the gas-liquid conversion device through the gas pressure control device;

[0009] A pressure reducing valve (4) and an air filter (5) are also respectively installed on the ventilation pipe (25).

[0010] Furthermore, the air pressure control device comprises a potentiometer (8), a single-pole double-throw switch (9), an electric proportional valve (10), a three-way connector (11) and a valve (12);

[0011] The gas-liquid conversion device comprises at least three gas-liquid conversion cylinders (13);

[0012] The three gas-liquid conversion cylinders (13) are respectively connected to the ventilation pipe (25) through pipelines.

[0013] A valve (12) is installed between the gas-liquid conversion cylinder (13) and the pipeline, and a three-way connector (11) is installed between the other end of the pipeline and the ventilation pipe (25);

[0014] An electric proportional valve (10) is installed on each of the three pipelines and the connected vent pipe (25), one end of the electric proportional valve (10) is installed on the pipeline, the other end of the electric proportional valve (10) is installed on the vent pipe (25), and a potentiometer (8) is installed on the extended end thereof via a single-pole double-throw switch (9);

[0015] The three single-pole double-throw switches (9) are respectively connected to one end of a computer (22) for controlling and collecting display data through installed wired lines to form a main line;

[0016] A pipeline is installed at the other end of the three gas-liquid conversion cylinders (13), and the other end of the pipeline is connected to the liquid-contaminated liquid conversion device;

[0017] An instrument case (14) is installed outside the air pressure control device and the air-liquid conversion device, an oil filling tank support frame (7) is installed on the instrument case (14), and an oil filling tank (6) is installed on the oil filling tank support frame (7).

[0018] A main water pipe is installed at the bottom end of the oil filling tank (6). The main water pipe passes through the box through three branched sub-water pipes and is respectively connected to the pipelines of the gas-liquid conversion cylinder (13).

[0019] Furthermore, the gas-liquid conversion cylinder (13) comprises a cylindrical gas-liquid conversion device body (31), and a gas-liquid conversion device stainless steel upper cover (27) and a gas-liquid conversion device stainless steel lower cover (28) are respectively installed at two ends of the gas-liquid conversion device body (31), and bolt holes are opened on the gas-liquid conversion device stainless steel upper cover (27) and the gas-liquid conversion device stainless steel lower cover (28), and tension bolts (29-1) are passed through the bolt holes, and the tension bolts (29-1) are installed on the gas-liquid conversion device stainless steel upper cover (27) and the gas-liquid conversion device stainless steel lower cover (28) through sleeve fixing screws (30-1);

[0020] An O-type sealing ring (32-1) is also installed at the connection between the stainless steel upper cover (27) of the gas-liquid conversion device, the stainless steel lower cover (28) of the gas-liquid conversion device and the column (31) of the gas-liquid conversion device.

[0021] Furthermore, the liquid-contaminated liquid conversion device comprises a liquid-contaminated liquid conversion cylinder (16), the liquid-contaminated liquid conversion cylinder (16) comprises an upper column (37) of the liquid-contaminated liquid conversion device and a lower column (38) of the liquid-contaminated liquid conversion device, and a stainless steel upper cover (33) of the liquid-contaminated liquid conversion device and a stainless steel lower cover (34) of the liquid-contaminated liquid conversion device are respectively mounted on the upper column (37) of the liquid-contaminated liquid conversion device and the lower column (38) of the liquid-contaminated liquid conversion device;

[0022] Bolt holes are provided on the stainless steel upper cover (33) of the liquid-contaminated liquid conversion device and the stainless steel lower cover (34) of the liquid-contaminated liquid conversion device, and two tension bolts (29-2) are passed through the bolt holes. The two tension bolts (29-2) are installed on the stainless steel upper cover (33) of the liquid-contaminated liquid conversion device and the stainless steel lower cover (34) of the liquid-contaminated liquid conversion device through two sleeve fixing screws (30-2);

[0023] An exhaust hole is also arranged on the stainless steel upper cover (33) of the liquid-contaminated liquid conversion device, and an exhaust hole screw plug (35) is arranged in the exhaust hole;

[0024] A flexible isolation membrane (36) that does not chemically react with pollutants is installed between the upper column (37) of the liquid-contaminated liquid conversion device and the lower column (38) of the liquid-contaminated liquid conversion device;

[0025] O-rings 2 (32-2) are sleeved at the connection points between the liquid-contaminated liquid conversion device stainless steel upper cover (33), the liquid-contaminated liquid conversion device stainless steel lower cover (34) and the liquid-contaminated liquid conversion device upper column (37) and the liquid-contaminated liquid conversion device lower column (38).

[0026] Furthermore, the contaminated liquid concentration adjusting device comprises a contaminated liquid mixing box (57), one end of the contaminated liquid mixing box (57) is connected to a high-concentration contaminated liquid injection tank (24) via a pipeline, the other end of the contaminated liquid mixing box (57) is connected to a solvent injection tank (53) via a pipeline, and the center end of the contaminated liquid mixing box (57) is connected to a low-concentration contaminated liquid injection tank (52) via a pipeline;

[0027] A flow pump (54) is installed at the connection between the pipeline and the high-concentration polluted liquid injection tank (24), the solvent injection tank (53) and the low-concentration polluted liquid injection tank (52);

[0028] At least two solution agitators (55) are also installed inside the contaminated liquid mixing box (57);

[0029] A main pipeline is also installed at the bottom of the polluted liquid mixing box (57), and the extended end of the main pipeline is connected to three liquid pipes (26) through a four-way joint (15), and the other ends of the three liquid pipes (26) are connected to the soil column shower device (17);

[0030] A thin pipe is also installed at the upper end of the liquid-contaminated liquid conversion cylinder (16), the other end of the thin pipe is respectively installed on the three liquid-passing pipes (26), and valves (12-2) are respectively installed at the connection between the thin pipe and the liquid-passing pipe (26);

[0031] A solution two-way valve (56) is also installed on the main pipeline.

[0032] Furthermore, the soil column shower device (17) comprises a soil column shower device stainless steel base (40), a soil column shower device column (47) is installed on the stainless steel base (40), and a soil column shower device stainless steel upper cover (39) is installed on the top of the soil column shower device column (47);

[0033] A bottom connecting belt (60) connected to the stainless steel base (40) of the soil column shower device is installed at the bottom of the soil column shower device column (47), and at least three fixing bolt holes are also opened on the bottom connecting belt (60) and the stainless steel base (40) of the soil column shower device;

[0034] A fixing connecting bolt (43) is passed through the fixing bolt hole, and a fixing screw (30-4) is sleeved on the fixing connecting bolt (43);

[0035] A support column (41) for supporting the soil column shower device (17) is also provided at the bottom end of the stainless steel base (40);

[0036] A valve three (12-3) is also installed on the stainless steel upper cover (39) of the soil column shower device, and a pressure gauge (46) is also installed on one side of the valve three (12-3);

[0037] A groove with a height of 1 cm is also installed at the center of the stainless steel base (40) of the soil column shower device.

[0038] A drainage belt (44) and a permeable stone (42) are arranged inside the groove.

[0039] Small holes are provided at the bottom drainage belt (44), the stainless steel base (40) of the soil column shower device and the center of the groove, and water outlets (45) are provided at the small holes;

[0040] A second water stop clamp (59) is also installed at the water outlet (45);

[0041] An O-shaped sealing ring (32-3) is also installed between the permeable stone (42) and the stainless steel base (40) of the soil column shower device;

[0042] A plastic concrete soil sample (21) is filled inside the soil column shower device column (47), and a crystal glaze glue (58) is coated between the plastic concrete soil sample (21) and the soil column shower device column (47).

[0043] Furthermore, a test platform (23) is installed at the lower end of the instrument box (14) including the air pressure control device and the air-liquid conversion device and the liquid-contaminated liquid conversion device, and an effluent liquid storage monitoring device is installed on the side wall of one side of the test platform (23);

[0044] The effluent storage monitoring device is connected to the second water stop clamp (59) of the water outlet (45) of the soil column shower device (17) through a pipeline.

[0045] Furthermore, the effluent storage monitoring device comprises a slender glass tube (19) arranged on the test platform (23), and a differential pressure sensor (20) is connected to the bottom end of the slender glass tube (19) through a three-way connector (11-2) installed thereon;

[0046] The other end of the water outlet (45) is connected to the second three-way connector (11-2) of the elongated glass tube (19);

[0047] The lower end of the elongated glass tube (19) is connected to an outflow liquid storage chamber (18) through a liquid flow tube, and a water stop clamp (51) is clamped on the liquid flow tube;

[0048] A conductivity sensor (48), a pH sensor (49) and a chloride ion concentration measuring sensor (50) are respectively installed at one end of the effluent storage chamber (18);

[0049] The conductivity sensor (48), pH sensor (49) and chloride ion concentration measuring sensor (50) are respectively connected to the other end of the computer (22) for controlling and collecting display data through connected wired lines.

[0050] Furthermore, a test method for a pollutant migration soil column device for plastic concrete, the specific operating steps are as follows:

[0051] (1) Assemble the pollutant migration test device, connect the various pipes of the device, and check the air tightness of the connections between the various parts of the device and the entire device;

[0052] (2) disassemble the soil column shower device (17), wash it in clean water and then wipe it dry;

[0053] (3) Close the water stop clamp 2 (59) under the stainless steel base (40) of the soil column shower device (17), place a permeable stone (42) and a filter paper on the base, and place the O-ring 3 (32-3) around the permeable stone (42);

[0054] (4) Fix the bottom connecting belt (60) of the soil column shower device column (47) to the stainless steel base (40) of the soil column shower device by fixing the connecting bolts (43) and the set fixing screws (30-4), fix the soil column shower device column (47) to the stainless steel base (40), fill the prepared plastic concrete soil sample (21) into the soil column shower device column (47), and use a tool to mix each section to evenly distribute the plastic concrete soil sample (21) until the required height is reached;

[0055] (5) The upper cover (39) of the soil column shower device, the column body (47) of the soil column shower device and the stainless steel base (40) of the soil column shower device are connected and fixed as a whole by tension bolts (29-3) and tension screws (30-3), and the soil column shower device (17) is placed in a curing room with a temperature of 20° C. and a humidity of 95% for curing for a prescribed time;

[0056] (6) Pushing the solid plastic concrete soil sample (21) after curing out of the soil column shower device column (47), applying crystal glaze glue (58) around the plastic concrete soil sample (21), and then pushing the plastic concrete soil sample (21) back into the original position in the soil column shower device (17), leaving it for three days to wait for the colloid to solidify;

[0057] (7) Inject the hydraulic oil from the bottom of the gas-liquid conversion device and stop when the oil reaches 90% of the conversion device;

[0058] (8) By calculation, the flow rates of the three flow pumps (54) of the polluted liquid concentration adjusting device are set, and polluted liquids of different concentrations are mixed in the polluted liquid mixing box (57) to obtain polluted liquids of a fixed target concentration;

[0059] (9) Inject the prepared contaminated liquid into the upper part of the conversion device through the upper valve of the liquid-contaminated liquid conversion device until all the air in the upper part of the device is exhausted;

[0060] Check the connecting pipe and exhaust all the air in it;

[0061] (10) Connect the water inlet of the soil column shower device (17) to the liquid-contaminated liquid device, adjust the electric proportional valve through the computer (22) that controls and collects display data, set the target water head size, start the air supply device, inject the pollutant solution into the three soil column shower devices (17), and exhaust the air in the column through the exhaust hole of the upper cover and then close the exhaust hole;

[0062] (11) The amount of water discharged from the drain pipe is recorded by a differential pressure sensor (20), and the chemical parameters of the liquid in the corresponding liquid storage chamber are measured by a conductivity, pH, and ion concentration measuring instrument to complete the migration test of pollutants in the plastic concrete soil sample (21) under different water heads; the liquid in the polluted liquid mixing box (57) is collected through a sealed test tube for later detection needs;

[0063] (12) After the test is completed, the soil column shower device (17) is removed, and the plastic concrete soil sample (21) is pushed out from the soil column shower device column (47) using an automatic hydraulic jacking device. The pollutant content at different depths is measured, and the polluted liquid in the liquid-polluted liquid conversion cylinder is taken out and placed in a chemical collection barrel for centralized treatment.

[0064] Beneficial effects: Compared with the prior art, the present invention has the following features: 1) The present invention provides a soil column device for the migration of pollutants in plastic concrete, including an air supply device, an air pressure control device, an air-liquid conversion device, a liquid-to-contaminated liquid conversion device, a contaminated liquid concentration adjustment device, a soil column shower device, and a shower liquid collection and monitoring device. The air pressure is regulated by the air pressure control device, and high-precision control of the hydraulic pressure is achieved; 2) Due to the use of a compressor, an air storage tank, and an air filter, a higher and more stable pressure can be provided. For plastic concrete, a soil with a very low permeability coefficient, the present invention can provide high head pressure, and can simulate the migration of pollutants in plastic concrete under high head in the laboratory, which is more in line with the actual situation; 3) In the present invention, each shower soil column is provided with an air pressure control device to realize independent control of multiple soil columns, and multiple groups of shower tests under different heads can be carried out simultaneously; 4) The gas-liquid conversion device, liquid-contaminated liquid conversion device and soil column shower device of the present invention are all made of high-strength corrosion-resistant stainless steel upper and lower covers fixed by tension bolts, which have higher strength and can ensure the safety and sealing of the device under high pressure in the column; 5) The liquid is contaminated liquid conversion device of the present invention, which isolates ordinary liquid and contaminated liquid through a flexible isolation membrane of inert material, and empties the upper air through the exhaust hole, so that the contaminated liquid is always isolated from the air, ensuring that the chemical composition in the contaminated liquid remains unchanged for a long time; 6) The contaminated liquid of the present invention can The contaminated liquid of different concentrations is automatically mixed by a flow pump, and the flow rate of the flow pump is controlled to configure the contaminated liquid. The desired concentration of the contaminated liquid is obtained after sufficient stirring in the contaminated liquid mixing box, thereby realizing high-precision configuration and dynamic allocation of the contaminated liquid of the target concentration; 7) The differential pressure sensor of the detection system of the present invention calculates the liquid outflow rate by measuring the differential pressure of the outflowing liquid, which is more accurate than manual readings; 8) The side wall of the soil column shower device of the present invention that contacts the plastic concrete is bonded with crystal glaze glue, which can ensure the adhesion and sealing between the column and the plastic concrete column, effectively prevent the contaminated liquid from measuring the flow, and facilitate the removal after the test without damaging the sample; 9) The effluent storage chamber of the present invention is provided with a conductivity sensor, a pH sensor and a chloride ion sensor, which are transmitted to a computer through a data line, and the conductivity, pH and chloride ion concentration changes in the effluent can be obtained, which is simpler and more accurate than manual operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0066] Figure 2 It is a structural schematic diagram of a gas-liquid conversion cylinder, a stainless steel upper cover of the gas-liquid conversion device, and a stainless steel lower cover of the gas-liquid conversion device in the gas-liquid conversion device of the present invention;

[0067] Figure 3It is a structural schematic diagram of the tension bolts, fixing screws, the column of the gas-liquid conversion device and the O-ring in the gas-liquid conversion device of the present invention;

[0068] Figure 4 It is a structural schematic diagram of a liquid-contaminated liquid conversion cylinder, a liquid-contaminated liquid conversion device stainless steel upper cover, a liquid-contaminated liquid conversion device stainless steel lower cover and a venting hole screw plug in the liquid-contaminated liquid conversion device of the present invention;

[0069] Figure 5 It is a structural schematic diagram of a flexible isolation membrane that does not chemically react with pollutants, an upper column of the liquid-contaminated liquid conversion device, and a lower column of the liquid-contaminated liquid conversion device in the liquid-contaminated liquid conversion device of the present invention;

[0070] Figure 6 It is a schematic diagram of the components of each device in the polluted liquid concentration adjustment device of the present invention;

[0071] Figure 7 This is a schematic diagram of the components of the soil column shower device of the present invention. Figure 1 ;

[0072] Figure 8 This is a schematic diagram of the components of the soil column shower device of the present invention. Figure 2 ;

[0073] Fig. 9 This is a schematic diagram of the components of the soil column shower device of the present invention. Figure 3 ;

[0074] Fig.10 This is a schematic diagram of the components of the soil column shower device of the present invention. Figure 4 ;

[0075] Fig.11 It is a schematic diagram of the components of the effluent storage monitoring device of the present invention;

[0076] Fig.12 It is a schematic diagram of a flow rate setting scheme for three flow pumps in a polluted liquid concentration adjustment device in an embodiment of the present invention;

[0077] In the figure, 1 is an air compressor; 2 is a variable diameter adapter; 3 is an air storage tank; 4 is a pressure reducing valve; 5 is an air filter; 6 is an oil filling tank; 7 is an oil filling tank support frame; 8 is a potentiometer; 9 is a single-pole double-throw switch; 10 is an electric proportional valve; 11 is a three-way connector 1; 11-2 is a three-way connector 2; 12 is a valve 1; 12-2 is a valve 2; 12-3 is a valve 3; 13 is a gas-liquid conversion cylinder; 14 is an instrument box; 15 is a four-way connector; 16 is a liquid-contaminated liquid conversion cylinder; 17 is a soil column shower device; 18 is an effluent storage chamber; 19 is a fine long glass tube; 20 is a differential pressure sensor; 21 is a plastic concrete soil sample; 22 is a computer for controlling and collecting display data; 23 is a test platform; 24 is a high-concentration contaminated liquid injection tank; 25 is a vent pipe; 26 is a liquid pipe; 27 is a stainless steel upper cover of a gas-liquid conversion device; 28 is a stainless steel lower cover of a gas-liquid conversion device; 29-1 is a tension bolt 1; 29-2 is a tension bolt 2; 29-3 is a tension bolt 3; 30-1 is a fixing screw 1; 30-2 is a fixing screw 2; 30-3 is a fixing screw 3; 30-4 is a fixing screw 4; 31 is the column of the gas-liquid conversion device; 32-1 is an O-ring 1; 32-2 is an O-ring 2; 32-3 is an O-ring 3; 33 is a stainless steel upper cover of the liquid-contaminated liquid conversion device; 34 is a stainless steel lower cover of the liquid-contaminated liquid conversion device; 35 is a vent plug; 36 is a flexible isolation membrane that does not chemically react with pollutants; 37 is the upper column of the liquid-contaminated liquid conversion device; 38 is the lower column of the liquid-contaminated liquid conversion device; 39 is a stainless steel upper cover of the soil column shower device; 40 is a stainless steel base of the soil column shower device; 41 is a support column; 42 is Permeable stone; 43 is the fixing connecting bolts between the column and the base; 44 is the bottom drainage belt; 45 is the water outlet; 46 is the pressure gauge; 47 is the column of the soil column shower device; 48 is the conductivity sensor; 49 is the pH sensor; 50 is the chloride ion concentration measurement sensor; 51 is the water stop clamp; 52 is the low-concentration polluted liquid injection tank; 53 is the solvent injection tank; 54 is the flow pump; 55 is the solution agitator; 56 is the solution two-way valve; 57 is the polluted liquid mixing box; 58 is the crystal glaze glue; 59 is the second water stop clamp; 60 is the bottom connecting belt of the column of the soil column shower device. DETAILED DESCRIPTION

[0078] In order to more clearly illustrate the technical solution of the present invention, the technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings:

[0079] The pollutant migration soil column device for plastic concrete described in the present invention comprises an air supply device, an air pressure control device, an air-liquid conversion device, a liquid-polluted liquid conversion device, a polluted liquid concentration adjustment device, a soil column shower device and an effluent storage monitoring device;

[0080] The air supply device is fixedly installed on a flat ground. Air enters the air compressor 1 through the air inlet, and the high-pressure gas obtained by the air compressor enters the air storage tank 3 through the high-pressure air pipe. The high-pressure gas in the air storage tank 3 passes through the air outlet and enters the air filter 5 for filtration, and then passes through the pressure reducing valve 4 to preliminarily adjust its pressure.

[0081] The air pressure control device includes an electric proportional valve 10, a single-pole double-throw switch 9, a potentiometer 8 and a computer 22 for controlling and collecting display data. The switch is connected to the computer 22, and the pressure target value of the electric proportional valve 10 is set by the computer 22, or the switch is connected to the potentiometer 8, and the target value is manually adjusted by the potentiometer 8 (alternative control scheme);

[0082] The gas-liquid conversion device has a control valve at the upper and lower parts, the upper valve controls the upper part to be connected to the atmosphere or the regulated air pressure, and the lower valve controls the connection to the hydraulic oil storage chamber or the liquid-contaminated liquid conversion device;

[0083] The liquid-contaminated liquid conversion device has a valve at the top for controlling the connection between the contaminated liquid mixing box 57 and the shower equipment, a valve at the bottom for connecting the liquid in the gas-liquid conversion device, an exhaust hole at the top for exhausting air, and an inert flexible isolation membrane 36 in the middle of the conversion device to realize the transmission of the lower self-hydraulic pressure to the upper contaminated liquid hydraulic pressure;

[0084] The contaminated liquid concentration preparation device comprises a contaminant-free solvent, a low-concentration contaminated liquid solution and a high-concentration contaminated liquid storage tank, and the contaminant preparation to the target concentration is achieved through the control of the flow pump 54;

[0085] The soil column shower device is provided with a valve, the upper valve is connected to the polluted liquid, the lower valve is connected to the pressure difference sensor 20 and the effluent liquid storage chamber 18, and is connected to the liquid-polluted liquid conversion device through a connecting pipe. The test tube outlet at the bottom of the shower device is connected to a drain pipe, and a pressure difference sensor 20 is provided at the drain pipe to measure the volume of the connected liquid. The water stop clamp 51 is opened, and the effluent enters the effluent liquid storage chamber 18. Each effluent liquid storage chamber 18 is provided with a conductivity sensor 48, a pH sensor 49 and a chloride ion concentration measurement sensor 50.

[0086] Furthermore, the compressor in the air supply device is placed on a flat ground with a relatively large open space to meet the conditions for heat dissipation and air intake.

[0087] Furthermore, the high-pressure air outlet of the air compressor 1 in the air supply device is connected together with the high-pressure pipe of the air compressor 1 and the air inlet pipe of the air storage tank 3 through a variable diameter adapter 2 to ensure good air tightness.

[0088] Furthermore, the gas storage tank 3 in the gas supply device is equipped with a pressure gauge and a safety valve. The pressure gauge is used to measure the air pressure in the pipe in real time, and the safety valve is used to quickly release pressure in an emergency. The capacity of the gas storage tank 3 must be above 30L to ensure the stability of the gas supply pressure.

[0089] Furthermore, the air filter 5 in the air supply device has a filtering accuracy of 5 μm, and the number of the air filter 5 should be two or more to ensure the filtering of the gas.

[0090] Furthermore, the air pressure control device includes an electrical proportional valve 10, a single-pole double-throw switch 9, a potentiometer 8 and a computer for inputting control signals (a computer 22 for controlling and collecting display data); the pressure setting range of the electrical proportional valve 10 is 0.005-1MPa, and the adjustment accuracy is 0.1kpa, which can meet the high-precision adjustment of different water heads (high, medium and low water heads), and the error head is within 1cm.

[0091] Furthermore, the switch of the air pressure control device is connected to a computer (a computer 22 for controlling and collecting display data), and the electrical proportional valve 10 is controlled by the computer; when the computer fails, the switch can be connected to the potentiometer 8, and the potentiometer 8 can be rotated to adjust and set the target pressure value of the electrical proportional valve 10.

[0092] Furthermore, there is a valve at the top and bottom of the gas-liquid conversion device; the upper valve controls the upper part of the gas-liquid conversion device to connect to the air pressure adjusted by the electrical proportional valve 10 or to the atmosphere, and the lower valve controls the lower part of the gas-liquid conversion device to connect to the hydraulic oil storage chamber or the liquid-contaminated liquid conversion device.

[0093] Furthermore, the hydraulic oil in the gas-liquid conversion device is high-quality anti-wear hydraulic oil.

[0094] Furthermore, the liquid-contaminated liquid conversion device is composed of an inert (non-reactive with the contaminated liquid) flexible isolation membrane (a flexible isolation membrane 36 that does not chemically react with the contaminants) at the upper and lower parts; the lower area is connected to the hydraulic oil, and the upper area is pre-loaded with the prepared contaminated liquid; the lower part of the device is equipped with a valve to control the input of the upstream hydraulic oil; the upper part of the device is equipped with a valve to control the connection to the contaminated liquid mixing box or the soil column shower device 17.

[0095] Furthermore, the upper cover of the liquid-contaminated liquid conversion device is provided with an exhaust hole with a diameter of 2 mm and a sealing screw plug, which is used to completely exhaust the air in the upper area containing the contaminated liquid to prevent the components in the air from reacting with the pollutants in the contaminated liquid.

[0096] Furthermore, the pollutant-free solvent in the polluted liquid concentration adjusting device is deionized water if the pollutant is an inorganic substance; and is an organic solvent if the pollutant is an inorganic substance.

[0097] Furthermore, the flow rate setting schemes of the three flow pumps in the pollution liquid concentration adjustment device are as Fig.12 described;

[0098] If c < c2, then q1 = 0, q2 = 1, q3 = c / c2 - c; if c2 < c < c1, then q1 = (c - c2) / (c1 - c), q2 = 1, q3 = 0, where c1 is the high-concentration pollutant concentration, c2 is the low-concentration pollutant concentration, q1 is the high-concentration pollutant flow rate, q2 is the low-concentration pollutant flow rate, and q3 is the solvent flow rate.

[0099] Furthermore, the soil column shower device 17 includes a stainless steel upper cover 39, a column body 47, a bottom stainless steel base 40, and upper and lower connecting bolts and fixing screws; the upper cover is circular, with a pressure gauge 46, a valve, and an exhaust hole on the upper part, three anchor bolt holes on the edge, the lower base is concave in the middle and convex at the edge, and an annular groove is provided at the outermost edge of the middle concave part to place an O-ring.

[0100] Furthermore, the column body 47 of the soil column shower device 17 of the soil column shower device is made of transparent acrylic material, with a height of 0.5 m - 1.5 m, an outer diameter of 12 - 25 cm, and an inner diameter of 10 - 20 cm; a bottom connecting belt 60 is provided at the bottom edge of the column body, which is connected to the column body 47 of the soil column shower device, and six screw holes are provided.

[0101] Furthermore, the side wall of the column body 47 of the soil column shower device in contact with the plastic concrete soil sample 21 is bonded with crystal glaze glue 58.

[0102] Furthermore, three acrylic support columns 41 and a water outlet 45 are provided at the lower part of the base of the soil column device; three anchor tension bolts are provided in each support column; there are fixing screws on the upper part of the base, which are initially connected to the bottom of the column body and fixed with screws; from bottom to top in the middle of the upper part of the base are a bottom drainage belt 44 and permeable stones 42, and an annular groove is provided around the permeable stones 42 to set an O-ring.

[0103] Furthermore, a differential pressure sensor 20 and a graduated slender glass tube 19 are provided at the water outlet 45 of the soil column shower device; a valve is provided downstream of the differential pressure sensor 20, and the valve controls the outflow liquid to enter the outflow liquid storage chamber 18; a pH sensor 49, a conductivity sensor 48, and a chloride ion concentration measurement sensor 50 are provided in the outflow liquid storage chamber 18, which can measure the chemical properties of the collected liquid.

[0104] Furthermore, the upper and lower covers of the gas-liquid conversion device, the upper and lower covers of the liquid-pollution liquid conversion device, and the upper cover base of the soil column shower are all made of 306 stainless steel material, with the characteristics of high strength and corrosion resistance.

[0105] A test method for a pollutant migration soil column device for plastic concrete as described in any one of the above; comprising the following steps:

[0106] Step 1: Assemble the pollutant migration test device, connect the various pipes of the device, and check the air tightness of the connections of various parts of the device and the entire device;

[0107] Step 2, disassemble the soil column shower device 17, put it into clean water to clean it and then wipe it dry;

[0108] Step 3, close the water stop clamp 2 59 under the base 40 of the soil column shower device, place a permeable stone 42 and a filter paper on the base 40 of the soil column shower device, and place an O-shaped sealing ring around the permeable stone;

[0109] Step 4, fix the connection part at the bottom of the soil column shower device column 47 to the soil column shower device column 47 by bolts, fill the configured plastic concrete soil sample 21 into the soil column shower device column 47, and use tools to mix each time a section is filled to make the plastic concrete soil sample 21 evenly distributed until the required height is reached;

[0110] Step 5, place the soil column shower device 17 in a curing room with a temperature of 20°C and a humidity of 95% and cure for a specified time;

[0111] Step 6: Push the plastic concrete soil sample 21 after curing out of the soil column shower device column 47, apply the crystal glaze glue 58 around the soil column shower device column 47, and then push the soil column shower device column 47 into the original position in the soil column shower device 17, and leave it for three days to wait for the colloid to solidify;

[0112] Step 7, inject the hydraulic oil from the bottom of the gas-liquid conversion device and stop when the injection reaches 90% of the conversion device;

[0113] Step 8: By calculation, the flow rates of the three flow pumps 54 of the polluted liquid concentration adjusting device are set, and polluted liquids of different concentrations are mixed in the polluted liquid mixing box 57 to obtain polluted liquids of a configured fixed target concentration;

[0114] Step 9, inject the prepared contaminated liquid into the upper part of the conversion device through the upper valve of the liquid-contaminated liquid conversion device until all the air in the upper part of the device is exhausted; check the connecting pipe and exhaust all the air in the connecting pipe;

[0115] Step 10, connect the water inlet of the soil column shower device 17 to the liquid-contaminated liquid device, adjust the electrical proportional valve 10 through the computer, set the target water head size, start the air supply device, inject the pollutant solution into the three soil column shower device cylinders 47, and exhaust the air in the column through the exhaust hole of the stainless steel upper cover 39 of the soil column shower device and then close the exhaust hole;

[0116] Step 11, the amount of water discharged from the drain pipe is recorded by the differential pressure sensor 20, the chemical parameters of the liquid in the corresponding effluent storage chamber 18 are measured by the conductivity, pH, and ion concentration measuring instruments, and the migration test of pollutants in the plastic concrete soil sample 21 under different water heads is completed; the liquid in the effluent storage chamber 18 is collected by a sealed test tube for later detection needs;

[0117] Step 12, after the test is completed, the soil column shower device 17 is removed, and the plastic concrete soil sample 21 is pushed out from the column 47 of the soil column shower device using an automatic hydraulic jacking device, and the pollutant content at different depths is measured, and the polluted liquid in the liquid-contaminated liquid conversion cylinder is taken out and placed in a chemical collection barrel for centralized treatment.

[0118] Specifically, Figures 1 to 11 As shown, the present invention provides a pollutant migration test device suitable for plastic concrete, including an air supply device, three air pressure control devices, three gas-liquid conversion devices, three liquid-pollutant conversion devices, a pollutant concentration adjustment device, three soil column shower devices, three effluent storage monitoring devices and a computer 22 for inputting, collecting and displaying data;

[0119] The air supply device is composed of an air compressor 1, a variable diameter adapter 2, an air storage tank 3, two air filters 5 and a pressure reducing valve 4 connected to each other through a pressure hose 25; the air pressure control device is controlled by an electric proportional valve 10, a single-pole double-throw switch 9, a potentiometer 8 and a computer 22 for inputting signals through circuit connection, and the lower end of each control device is connected to a gas-liquid conversion cylinder 13 through a valve 12 and a pressure hose (ventilation pipe 25), and the upper end of each control device is connected to the high-pressure gas in the air storage tank 3 through a three-way connector 11 and a ventilation pipe 25;

[0120] The gas-liquid conversion device is composed of two upper and lower valves 12 and a gas-liquid conversion cylinder 13. The upper part of the gas-liquid conversion cylinder 13 is connected by the upper valve control. The gas regulated by the electric proportional valve 10 enters the upper part of the cylinder through the upper valve 12, and the liquid enters the liquid-contaminated liquid conversion device through the lower valve 12 under the action of gas pressure.

[0121] The liquid-contaminated liquid conversion device is formed by connecting a liquid-contaminated liquid conversion cylinder 16, a valve 12 and a four-way joint 15 through a hydraulic hose (liquid pipe 26). The lower end joint and the liquid enter the lower part of the liquid-contaminated liquid conversion cylinder from the lower end of the gas-liquid conversion device, push the flexible isolation membrane (flexible isolation membrane 36 that has no chemical reaction with the pollutants), and the contaminated liquid in the upper cylinder body enters the soil column shower device 17;

[0122] The polluted liquid concentration preparation device is composed of a high-concentration polluted liquid injection tank 24, a low-concentration polluted liquid injection tank 52, a solvent injection tank 53, a flow pump 54, a solution agitator 55 and a polluted liquid mixing box 57. The flow rate of the flow pump 54 under different tanks is set by calculation, and the high-concentration polluted liquid, the low-concentration polluted liquid and the solvent flow into the polluted liquid mixing box 57. Under the stirring of the solution agitator 55, the target concentration of polluted liquid is obtained; the soil column shower device 17 of the polluted liquid is composed of a stainless steel upper cover 39 of the soil column shower device, an acrylic soil column shower device The device column 47, the soil column shower device stainless steel base 40, tension bolts, fixing screws and crystal glaze glue 58 are composed. The polluted liquid enters the column through the upper end interface of the soil column shower device 17, passes through the plastic concrete sample 21, the permeable stone 42, the filter paper and the bottom drainage belt 44 in turn, enters the pressure difference sensor 20 and the slender glass pavilion 19 through the outflow liquid interface 45, opens the water stop clamp 51, and the outflow liquid enters the storage chamber 18. Each liquid storage chamber 18 is provided with a concentration measuring instrument that can detect the conductivity, pH and chloride ion concentration of the liquid concentration therein.

[0123] The air supply device is composed of an air compressor 1, a variable diameter adapter 2, an air tank 3, two air filters 5 and a pressure reducing valve 4 connected to each other through a pressure hose; the air is compressed by the compressor 1 and enters the air tank 3 through the variable diameter interface 2 and the pressure hose; the air tank 3 is provided with a pressure gauge to monitor the air pressure inside the tank in real time; the air filter 5 is installed at the outlet of the air tank 3 to filter the compressed gas in the tank; the pressure reducing valve 4 is installed between the two air filters 5 or downstream of the two air filters 5 to achieve preliminary regulation of the gas pressure; the gas after filtration and pressure reduction is divided into three ways through two three-way joints to enter the upstream of the electric proportional valve 10.

[0124] Each of the air pressure control devices is provided with two control methods, namely, a common mode and a backup mode; the common mode: the single-pole double-throw switch 9 is connected to a computer (computer 22 for controlling and collecting display data), and a control signal is input into the computer to realize precise control of the electric proportional valve 10;

[0125] Backup method: connect the single-pole double-throw switch 9 to the potentiometer 8, and change the output of the electrical signal by rotating the potentiometer 8 to control the electrical proportional valve 10; in addition to the above two methods, a single-chip microcomputer combination key control can be set, and the control method is not limited.

[0126] Each gas-liquid conversion cylinder is composed of a gas-liquid conversion cylinder upper cover 27, a gas-liquid conversion cylinder lower cover 28, an acrylic transparent column 31, two O-shaped sealing rings 32, four tension bolts 29 and eight screws 30. The two sealing rings are respectively placed at the contact point between the upper and lower covers and the column, and are fixed by four tension bolts 29 and eight screws 30 to form a sealed space.

[0127] The gas-liquid conversion device is composed of two upper and lower valves and a gas-liquid conversion cylinder 13; the upper valve is rotated to the right, the upper part of the gas-liquid conversion cylinder is connected to the air pressure adjusted by the electric proportional valve 10, and the gas-liquid conversion cylinder is rotated to the left to connect to the atmosphere; the lower valve is rotated to the right, the lower part of the gas-liquid conversion cylinder is connected to the lower part of the liquid-contaminated liquid conversion cylinder, and it is rotated to the left to connect to the tap water injection tank 6 for adding water.

[0128] Each of the liquid-contaminated liquid conversion cylinders is composed of a stainless steel upper cover 33 of the liquid-contaminated liquid conversion cylinder, a stainless steel lower cover 34 of the liquid-contaminated liquid conversion cylinder, a flexible isolation membrane 36 that does not react chemically with pollutants, an upper column 37 of the liquid-contaminated liquid conversion device, a lower column 38 of the liquid-contaminated liquid conversion device, an upper exhaust hole screw plug 35, 2 O-rings, 4 tension bolts and 8 screws; the joints of the upper column 37 of the liquid-contaminated liquid conversion device and the lower column 38 of the liquid-contaminated liquid conversion device are specially designed to fix the edge of the flexible isolation membrane 36 that does not react chemically with pollutants at the joint of the upper and lower columns. By setting an O-ring at the contact between the column and the upper and lower covers, and by tension bolts and screws, all components are fixed together to form two upper and lower isolated closed cavities.

[0129] The upper valve of each liquid-contaminated liquid conversion cylinder controls the outflow direction of the contaminated liquid. Rotate the valve to the left, connect the contaminated liquid mixing box 57 through the four-way connector 15 and the infusion hose 26, the contaminated liquid mixing box 57 is connected to the high-concentration contaminated liquid injection tank 24, the low-concentration contaminated liquid injection tank 52, and the solvent injection tank 53. The three injection tanks are respectively connected to the flow pump 54 below, and the flow rate of different solutions is controlled by the flow pump 54. After the contaminated liquid mixing box 57 is fully stirred by the solution agitator 55, the required concentration of contaminated liquid can be automatically prepared; open the exhaust hole, and when the upper cavity is completely filled with contaminated liquid, tighten the exhaust hole screw plug 35; the adjusted air pressure pushes the liquid in the air pressure conversion cylinder into the lower part of the liquid-contaminated liquid conversion cylinder 16, and the lower liquid in the cylinder passes through the flexible isolation membrane, pushing the upper contaminated liquid into the soil column shower device with a fixed head pressure.

[0130] The soil column shower device 17 is composed of a soil column shower device stainless steel cover 39, an acrylic soil column shower device column 47, and a soil column shower device stainless steel base 40; the soil column shower device stainless steel cover 39 includes a cover body, a valve, a pressure gauge 46, an exhaust hole screw plug 33 and an O-ring;

[0131] A connecting belt with a protruding outer ring is provided at the bottom of the acrylic soil column shower device column 47, and six screw holes are provided on each connecting belt, three of which are tension bolt holes, and three are connection bolt holes 43 between the column and the base; the stainless steel base 40 of the soil column shower device includes a stainless steel base body, three supporting columns 41, a permeable stone 42, 3 connecting bolts, a drainage belt 44, an outflow port 45, tension bolts and fixing screws; the polluted liquid enters the soil column shower device 17 with a fixed head pressure, and the exhaust hole is closed after filling to ensure that the pollutants in the polluted liquid have no chemical reaction, and enters the plastic concrete sample 21 with a constant head; in order to ensure the integrity of the sample, a filter paper and a permeable stone 42 are placed at the bottom of the sample, and a bottom drainage belt 44 is provided to facilitate the outflow of the outflow liquid.

[0132] The effluent storage monitoring device includes a differential pressure sensor 20, a slender glass tube 19, a three-way joint, a liquid storage chamber 18, a conductivity sensor 48, a pH sensor 49, a chloride ion concentration measuring sensor 50 and a water stop clamp 51; the pressure difference is obtained through the differential pressure sensor 20 and the slender glass tube 19 to calculate the outflow volume; the water stop clamp 51 is opened, and the effluent enters the liquid storage chamber 18, and the changes in the chemical properties of the effluent are monitored in real time through the conductivity sensor 48, the pH sensor 49, the chloride ion concentration measuring sensor 50 and the calculation 2.

[0133] Example 1, a method for a pollutant migration soil column device for plastic concrete is as follows:

[0134] 1) After assembling and connecting all parts of the test device, connect the upper and lower valves of the gas-liquid conversion cylinder to the electrical proportional valve 9 and the liquid-contaminated liquid conversion cylinder 16 respectively, connect the upper valve of the liquid-contaminated liquid conversion cylinder 16 to the soil column shower device 17, and close the water stop clamp 51 at the bottom of the soil column shower device 17; set the pressure of the three electrical proportional valves to 20 kPa, start the air compressor 1, observe the pressure gauge 46 on the gas storage tank 2 and the soil column shower device 17, and judge the internal sealing of the whole device;

[0135] 2) The soil column shower device 17 is separated into a soil column shower device stainless steel upper cover 39, an acrylic soil column shower device column 47, and a soil column shower device stainless steel base 40, and the above three parts are cleaned with clean water and wiped dry.

[0136] 3) Close the water stop clamp 51 under the base of the soil column shower device, place a permeable stone 42 and a filter paper on the base, and place an O-ring around the permeable stone 42;

[0137] 4) Fix the shower device column 47 to the base 40 through the bottom connection part and the fixing bolts 43, and fill the prepared plastic concrete 21 into the soil column shower device column 47. After each filling, use a glass rod to stir the plastic concrete to make it evenly distributed until the required height is reached.

[0138] 5) Fix the stainless steel upper cover 39 of the soil column shower device to the upper part of the acrylic soil column shower device column 47 by tension bolts and screws, and put the soil column shower device 17 into a standard curing room with a temperature of 20° C. and a humidity of 95% for curing for the prescribed time of 28 days;

[0139] 6) Push the plastic concrete soil sample 21 after curing out of the column 47 of the soil column shower device, apply the crystal glaze glue 58 around the sample, and then push the column 47 of the soil column shower device into the original position in the soil column shower device 17, and leave it for three days to wait for the crystal glaze glue 58 to solidify;

[0140] 7) Setting the flow rates of the flow pump 54 for the high-concentration polluted liquid 10000 mg / L and the low-concentration polluted liquid 5000 mg / L to 1 mL / s and 1 mL / s respectively, mixing the two concentrations of polluted liquid in the polluted liquid mixing box 57 to obtain a polluted liquid with a target concentration of 7500 mg / L;

[0141] 8) Open the upper and lower valves of the gas-liquid conversion cylinder 13, connect the upper valve to the atmosphere, and connect the lower valve to the water injection tank 6. Inject hydraulic oil into the gas-liquid conversion cylinder 13 under the action of its own weight, and stop when the injection reaches 90% of the conversion device; 2+ The polluted liquid is added with pollutants and injected into the high-concentration polluted liquid injection tank 24, the upper valve of the liquid-polluted liquid conversion cylinder 16 is opened, the exhaust hole screw plug 35 is removed, and the polluted liquid is injected until the air in the upper part of the device is exhausted and the upper cavity is filled, and the exhaust hole screw plug 35 is tightened to close the exhaust hole; check the connecting hose (liquid pipe 26) and exhaust all the air in the connecting pipe;

[0142] 9) Open the valve of the stainless steel upper cover 39 of the soil column shower device, connect it to the liquid-contaminated liquid conversion cylinder 16 through a pipeline, and open the exhaust hole of the stainless steel upper cover 39 of the soil column shower device; according to the test plan, determine that the three target water heads are 5m, 10m and 15m respectively, and the corresponding target pressures are 50kPa, 100kPa and 150kPa respectively. Connect the single-pole double-throw switch 9 to the computer 22 that controls and collects display data, and set the target pressure values ​​of the three electrical proportional valves 9 to 50kPa, 100kPa and 150kPa respectively. Start the air compressor 1, inject the pollutant solution into the three soil columns, and tighten the exhaust hole screw plug 35 after exhausting the air in the column through the exhaust hole of the upper cover, observe the pressure gauge 46 of the stainless steel upper cover 39 of the soil column shower device, and compare whether the internal pressure of the soil column is the same as the set pressure;

[0143] 10) The amount of water discharged is measured by the differential pressure sensor 20. Every 1 hour, the water stop clamp 51 is opened, and the effluent enters the effluent storage chamber 18 from the slender glass tube 19. The chemical parameter changes of the effluent in the storage chamber are measured by the conductivity sensor 48, the pH sensor 49 and the chloride ion concentration measuring instrument 50 to complete the migration test of pollutants in plastic concrete under different water heads; the liquid in the liquid storage chamber 18 is collected through a sealed test tube for later detection needs;

[0144] 11) After the test is completed, the soil column shower device 17 is removed, the plastic concrete soil sample 21 is taken out from the column 47 of the soil column shower device, the heavy metal content at different depths is measured, and the contaminated liquid in the liquid-contaminated liquid conversion cylinder 16 is taken out and placed in a chemical collection barrel for centralized treatment.

[0145] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A soil column device for pollutant migration in plastic concrete, characterized in that: It includes an air supply device, an air pressure control device, an air-liquid conversion device, a liquid-contaminated liquid conversion device, a contaminated liquid concentration adjustment device, a soil column shower device and an effluent liquid storage monitoring device; The air supply device comprises an air compressor (1) and an air storage tank (3), wherein interconnected high-pressure air pipes are installed on the air compressor (1) and the air storage tank (3), and a variable diameter adapter (2) is installed between the interconnected high-pressure air pipes; A vent pipe (25) is installed at the output end of the gas storage tank (3); the other end of the vent pipe (25) is connected to the gas-liquid conversion device through the gas pressure control device; A pressure reducing valve (4) and an air filter (5) are also respectively installed on the ventilation pipe (25); The air pressure control device comprises a potentiometer (8), a single-pole double-throw switch (9), an electric proportional valve (10), a three-way connector (11) and a valve (12); The gas-liquid conversion device comprises at least three gas-liquid conversion cylinders (13); The three gas-liquid conversion cylinders (13) are respectively connected to the ventilation pipe (25) through pipelines. A valve (12) is installed between the gas-liquid conversion cylinder (13) and the pipeline, and a three-way connector (11) is installed between the other end of the pipeline and the ventilation pipe (25); An electric proportional valve (10) is installed on each of the three pipelines and the connected ventilation pipe (25), one end of the electric proportional valve (10) is installed on the pipeline, the other end of the electric proportional valve (10) is installed on the ventilation pipe (25), and a potentiometer (8) is installed on the extended end thereof via a single-pole double-throw switch (9); The three single-pole double-throw switches (9) are respectively connected to one end of a computer (22) for controlling and collecting display data through installed wired lines to form a main line; A pipeline is installed at the other end of the three gas-liquid conversion cylinders (13), and the other end of the pipeline is connected to the liquid-contaminated liquid conversion device; An instrument case (14) is installed outside the gas pressure control device and the gas-liquid conversion device, an oil filling tank support frame (7) is installed on the instrument case (14), and an oil filling tank (6) is installed on the oil filling tank support frame (7). A main water pipe is installed at the bottom end of the oil filling tank (6), and the main water pipe passes through the box through three branched sub-water pipes and is respectively connected to the pipelines of the gas-liquid conversion cylinder (13).

2. The pollutant migration soil column device for plastic concrete according to claim 1 is characterized in that: The gas-liquid conversion cylinder (13) comprises a cylindrical gas-liquid conversion device body (31), a gas-liquid conversion device stainless steel upper cover (27) and a gas-liquid conversion device stainless steel lower cover (28) are respectively installed at two ends of the gas-liquid conversion device body (31), bolt holes are opened on the gas-liquid conversion device stainless steel upper cover (27) and the gas-liquid conversion device stainless steel lower cover (28), a tension bolt (29-1) is passed through the bolt hole, and the tension bolt (29-1) is installed on the gas-liquid conversion device stainless steel upper cover (27) and the gas-liquid conversion device stainless steel lower cover (28) through a sleeve fixing screw (30-1); An O-type sealing ring (32-1) is also installed at the connection between the stainless steel upper cover (27) of the gas-liquid conversion device, the stainless steel lower cover (28) of the gas-liquid conversion device and the column (31) of the gas-liquid conversion device.

3. The pollutant migration soil column device for plastic concrete according to claim 1, characterized in that: The liquid-contaminated liquid conversion device comprises a liquid-contaminated liquid conversion cylinder (16), the liquid-contaminated liquid conversion cylinder (16) comprises a liquid-contaminated liquid conversion device upper column (37) and a liquid-contaminated liquid conversion device lower column (38), and a liquid-contaminated liquid conversion device stainless steel upper cover (33) and a liquid-contaminated liquid conversion device stainless steel lower cover (34) are respectively mounted on the liquid-contaminated liquid conversion device upper column (37) and the liquid-contaminated liquid conversion device lower column (38); Bolt holes are provided on the liquid-contaminated liquid conversion device stainless steel upper cover (33) and the liquid-contaminated liquid conversion device stainless steel lower cover (34), and two tension bolts (29-2) are passed through the bolt holes. The two tension bolts (29-2) are installed on the liquid-contaminated liquid conversion device stainless steel upper cover (33) and the liquid-contaminated liquid conversion device stainless steel lower cover (34) through two sleeve fixing screws (30-2); An exhaust hole is also installed on the stainless steel upper cover (33) of the liquid-contaminated liquid conversion device, and an exhaust hole screw plug (35) is installed in the exhaust hole; A flexible isolation membrane (36) that does not chemically react with pollutants is installed between the upper column (37) of the liquid-contaminated liquid conversion device and the lower column (38) of the liquid-contaminated liquid conversion device; O-rings 2 (32-2) are sleeved at the connection points between the liquid-contaminated liquid conversion device stainless steel upper cover (33), the liquid-contaminated liquid conversion device stainless steel lower cover (34), the liquid-contaminated liquid conversion device upper column (37), and the liquid-contaminated liquid conversion device lower column (38).

4. The pollutant migration soil column device for plastic concrete according to claim 1, characterized in that: The contaminated liquid concentration adjusting device comprises a contaminated liquid mixing box (57), one end of the contaminated liquid mixing box (57) is connected to a high-concentration contaminated liquid injection tank (24) via a pipeline, the other end of the contaminated liquid mixing box (57) is connected to a solvent injection tank (53) via a pipeline, and the center end of the contaminated liquid mixing box (57) is connected to a low-concentration contaminated liquid injection tank (52) via a pipeline; A flow pump (54) is installed at the connection between the pipeline and the high-concentration polluted liquid injection tank (24), the solvent injection tank (53) and the low-concentration polluted liquid injection tank (52); At least two solution agitators (55) are also installed inside the contaminated liquid mixing box (57); A main pipeline is also installed at the bottom of the polluted liquid mixing box (57), and the extended end of the main pipeline is connected to three liquid pipes (26) through a four-way joint (15), and the other ends of the three liquid pipes (26) are connected to the soil column shower device (17); A thin pipe is also installed at the upper end of the liquid-contaminated liquid conversion cylinder (16), the other end of the thin pipe is respectively installed on the three liquid-passing pipes (26), and valves (12-2) are respectively installed at the connection between the thin pipe and the liquid-passing pipe (26); A solution two-way valve (56) is also installed on the main pipeline.

5. The pollutant migration soil column device for plastic concrete according to claim 4, characterized in that: The soil column shower device (17) comprises a soil column shower device stainless steel base (40), a soil column shower device column (47) is mounted on the stainless steel base (40), and a soil column shower device stainless steel upper cover (39) is mounted on the top of the soil column shower device column (47); A bottom connecting belt (60) connected to the soil column shower device stainless steel base (40) is installed at the bottom of the soil column shower device column (47), and at least three fixing bolt holes are also opened on the bottom connecting belt (60) and the soil column shower device stainless steel base (40); A fixing connecting bolt (43) is passed through the fixing bolt hole, and a fixing screw (30-4) is sleeved on the fixing connecting bolt (43); A support column (41) for supporting the soil column shower device (17) is also provided at the bottom end of the stainless steel base (40); A valve three (12-3) is also installed on the stainless steel upper cover (39) of the soil column shower device, and a pressure gauge (46) is also installed on one side of the valve three (12-3); A groove with a height of 1 cm is also installed at the center of the stainless steel base (40) of the soil column shower device. A drainage belt (44) and a permeable stone (42) are installed inside the groove. Small holes are provided in communication with each other at the bottom drainage belt (44), the stainless steel base (40) of the soil column shower device, and the center of the groove, and water outlets (45) are provided in communication with each other at the small holes; A second water stop clamp (59) is also installed at the water outlet (45); An O-shaped sealing ring (32-3) is also installed between the permeable stone (42) and the stainless steel base (40) of the soil column shower device; A plastic concrete soil sample (21) is filled inside the soil column shower device column (47), and a crystal glaze glue (58) is applied between the plastic concrete soil sample (21) and the soil column shower device column (47).

6. The pollutant migration soil column device for plastic concrete according to claim 1, characterized in that: A test platform (23) is also installed at the lower end of the instrument box (14) including the gas pressure control device and the gas-liquid conversion device and the liquid-contaminated liquid conversion device, and an effluent liquid storage monitoring device is installed on the side wall of one side of the test platform (23); The effluent storage monitoring device is connected to the second water stop clamp (59) of the water outlet (45) of the soil column shower device (17) through a pipeline.

7. The pollutant migration soil column device for plastic concrete according to claim 6, characterized in that: The effluent storage monitoring device comprises a slender glass tube (19) arranged on the test platform (23), and a differential pressure sensor (20) is connected to the bottom end of the slender glass tube (19) via a two-way connector (11-2) installed thereon; The other end of the water outlet (45) is connected to the second three-way connector (11-2) of the slender glass tube (19); The lower end of the slender glass tube (19) is connected to an outflow liquid storage chamber (18) via a liquid flow tube, and a water stop clamp (51) is clamped on the liquid flow tube; A conductivity sensor (48), a pH sensor (49) and a chloride ion concentration measuring sensor (50) are respectively installed at one end of the effluent storage chamber (18); The conductivity sensor (48), pH sensor (49) and chloride ion concentration measuring sensor (50) are respectively connected to the other end of a computer (22) for controlling and collecting display data via connected wired lines.

8. A test method for a pollutant migration soil column device for plastic concrete as claimed in any one of claims 1 to 7, characterized in that: The specific steps are as follows: (1) Assemble the pollutant migration test device, connect the various pipes of the device, and check the connections between the various parts of the device and the air tightness of the various parts of the entire device; (2) Disassemble the soil column shower device (17), wash it in clean water and then wipe it dry; (3) Close the water stop clamp 2 (59) under the stainless steel base (40) of the soil column shower device (17), place a permeable stone (42) and a filter paper on the base, and place the O-ring 3 (32-3) around the permeable stone (42); (4) Fix the bottom connecting belt (60) of the soil column shower device column (47) to the stainless steel base (40) of the soil column shower device by fixing the connecting bolts (43) and the set fixing screws (30-4), fix the soil column shower device column (47) to the stainless steel base (40), fill the prepared plastic concrete soil sample (21) into the soil column shower device column (47), and use a tool to mix each section to evenly distribute the plastic concrete soil sample (21) until the required height is reached; (5) The upper cover (39) of the soil column shower device, the column body (47) of the soil column shower device and the stainless steel base (40) of the soil column shower device are connected and fixed as a whole by means of tension bolts (29-3) and tension screws (30-3), and the soil column shower device (17) is placed in a curing room at a temperature of 20° C. and a humidity of 95% for curing for a prescribed time; (6) Pushing the solid plastic concrete soil sample (21) after curing out of the soil column shower device column (47), applying crystal glaze glue (58) around the plastic concrete soil sample (21), and then pushing the plastic concrete soil sample (21) into the original position in the soil column shower device (17), leaving it for three days to wait for the colloid to solidify; (7) Inject the hydraulic oil from the bottom of the gas-liquid conversion device and stop when it reaches 90% of the conversion device; (8) setting the flow rates of the three flow pumps (54) of the polluted liquid concentration adjusting device by calculation, mixing polluted liquids of different concentrations in the polluted liquid mixing box (57) to obtain polluted liquids of a fixed target concentration; (9) Inject the prepared contaminated liquid into the upper part of the conversion device through the upper valve of the liquid-contaminated liquid conversion device until all the air in the upper part of the device is exhausted; Check the connecting pipe and exhaust all the air in it; (10) Connect the water inlet of the soil column shower device (17) to the liquid-contaminated liquid device, adjust the electric proportional valve through the computer (22) for controlling and collecting display data, set the target water head size, start the air supply device, inject the pollutant solution into the three soil column shower devices (17), and exhaust the air in the column through the exhaust hole of the upper cover and then close the exhaust hole; (11) The amount of water discharged from the drain pipe is recorded by a differential pressure sensor (20), and the chemical parameters of the liquid in the corresponding liquid storage chamber are measured by a conductivity, pH, and ion concentration measuring instrument to complete the migration test of pollutants in the plastic concrete soil sample (21) under different water heads; the liquid in the polluted liquid mixing box (57) is collected through a sealed test tube for later testing needs; (12) After the test is completed, the soil column shower device (17) is removed, and the plastic concrete soil sample (21) is pushed out from the soil column shower device column (47) using an automatic hydraulic jacking device. The pollutant content at different depths is measured, and the polluted liquid in the liquid-polluted liquid conversion cylinder is taken out and placed in a chemical collection barrel for centralized treatment.

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