A pressurized seepage device for simulating migration of pollutants in a frozen soil barrier

Abstract

The application discloses a pressurized seepage device for simulating migration of pollutants in a frozen soil barrier, and belongs to the field of geotechnical engineering equipment. The device solves the problems of inconvenient pressure control and long test time of the artificial frozen soil barrier pressurized seepage device in the prior art. In the application, a cavity is arranged in the container shell, and the cavity is filled with a frozen barrier; a reserved sampling hole in communication with the cavity is formed on the surface of the container shell; a seepage bin is fixedly installed in the cavity and wrapped by the frozen barrier; a cavity two is formed in the seepage bin; a seepage through hole in communication with the cavity two is formed on the surface of the seepage bin; a pollutant pressurized circulating device is in communication with the cavity two of the seepage bin through a pipeline; and the pollutant pressurized circulating device pressurizes and perfuses pollutant liquid into the cavity two of the seepage bin. The application has the advantages that the liquid pressurized mode can be used to accurately control the pressure and quickly obtain the barrier effect and service ability of the artificial frozen soil barrier.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of pressure seepage device for simulating the migration of pollutants in frozen soil barrier, belong to geotechnical engineering equipment field. BACKGROUND

[0002] Compared with bentonite, cement soil, geomembrane and other permanent barriers, frozen soil barrier is a good temporary barrier, using site geotechnical as raw material, without secondary pollution, and in the end of engineering, frozen soil barrier can be removed by natural warming. Frozen soil barrier has good impermeability, high strength, corrosion resistance, radiation resistance and other properties, contains mineral composition with strong adsorption capacity for pollutants, and has little impact on the environment. In the long run, frozen barrier can significantly reduce the release rate of pollutants, has long-term stability, and is a pollution barrier material with great development prospect.

[0003] Frozen soil barrier has low permeability, and pollutants migrate slowly in it, but as a new type of barrier, it is extremely important to evaluate its service ability and barrier ability. At the same time, under the condition of negative temperature, it is difficult to simulate the migration of pollutants in frozen soil barrier. Ordinary constant gravity test cannot quickly simulate the service ability and barrier ability. There are few tests on artificial frozen soil barrier at home and abroad. When studying the service ability and barrier ability of frozen soil barrier, the effective barrier to the migration of pollutants in frozen soil is the most critical problem. If conventional constant gravity test is selected, it cannot meet the rapid simulation under low temperature and low permeability conditions.

[0004] Traditional constant head and variable head pressurizing device is not suitable for the study of artificial frozen soil barrier, partly because the pressure that can be applied is small, and the time for pollutants to break through the barrier and the effect of the barrier on pollutants cannot be quickly simulated. Another part is that when the traditional pressurized permeation is carried out, pollutants will flow around the place where the barrier and the device are connected, resulting in barrier failure. SUMMARY

[0005] The present application provides a kind of pressure seepage device for simulating the migration of pollutants in frozen soil barrier, adopts liquid pressurization mode, can more accurately control pressure and quickly get the barrier effect and service ability of artificial frozen soil.

[0006] The technical scheme adopted by the present application is a kind of pressure seepage device for simulating the migration of pollutants in frozen soil barrier, comprising

[0007] The container shell (15) is internally provided with a cavity, and the frozen barrier (16) is filled in the cavity. The surface of the container shell (15) is provided with a reserved sampling hole (14) in communication with the cavity.

[0008] The seepage bin (19) is fixedly installed in the cavity one of the container shell (15) and is wrapped by the frozen barrier (16); the seepage bin (19) is internally constructed with a cavity two, and the surface of the seepage bin (19) is constructed with seepage through holes in communication with the cavity two;

[0009] The contaminant pressurized circulation device is in communication with the cavity two of the seepage bin (19) through a pipeline, and the contaminant pressurized circulation device pressurizes and fills the contaminant liquid into the cavity two of the seepage bin (19).

[0010] The seepage bin (19) is externally spherical, the cavity two of the seepage bin (19) is spherical, and the seepage through holes are uniformly constructed on the external wall of the seepage bin (19);

[0011] The external wall of the container shell (15) is spherical, the cavity one of the container shell (15) is spherical, and the seepage bin (19) is located at the central position of the cavity one of the container shell (15).

[0012] The seepage bin (19) is externally spherical, the cavity two of the seepage bin (19) is spherical, and the seepage through holes are uniformly constructed on the external wall of the seepage bin (19);

[0013] The seepage bin (19) is externally spherical, the cavity two of the seepage bin (19) is spherical, and the seepage through holes are uniformly constructed on the external wall of the seepage bin (19);

[0014] The contaminant pressurized circulation device comprises a liquid outlet pipe (20), a liquid inlet pipe (21), a waste liquid recovery device (5) and a cold bath device (11);

[0015] One end of the liquid outlet pipe (20) penetrates through the top end of the container shell (15), the top end of the seepage bin (19) and extends to the lower section inside the seepage bin (19), and the other end of the liquid outlet pipe (20) is connected with the waste liquid recovery device (5);

[0016] One end of the liquid inlet pipe (21) penetrates through the top end of the container shell (15), the top end of the seepage bin (19) and extends to the upper section inside the seepage bin (19), and the other end of the liquid inlet pipe (21) is connected with the cold bath device (11).

[0017] The optimized pressure seepage device for simulating the migration of pollutants in the frozen soil barrier is provided with a valve (8) for controlling the liquid flow in the liquid outlet pipe (20) in the middle section of the liquid outlet pipe (20), and a valve (9) for controlling the liquid flow in the liquid inlet pipe (21) in the middle section of the liquid inlet pipe (21).

[0018] The optimized pressure seepage device for simulating the migration of pollutants in the frozen soil barrier further comprises a temperature acquisition instrument (2), and the detection end of the temperature acquisition instrument (2) is located in the frozen barrier (16).

[0019] The optimized pressure seepage device for simulating the migration of pollutants in the frozen soil barrier is provided with a valve (8) for controlling the liquid flow in the liquid outlet pipe (20) in the middle section of the liquid outlet pipe (20), and a valve (9) for controlling the liquid flow in the liquid inlet pipe (21) in the middle section of the liquid inlet pipe (21).

[0020] The application has the following advantages:

[0021] In the technical scheme of the application, the pollutant liquid is injected into the seepage bin (19) by the pollutant pressurization and circulation device, and the injected pollutant liquid is pressurized by the pollutant pressurization and circulation device, so that the pollutant liquid seeps out of the seepage bin (19) and pressurizedly penetrates into the frozen barrier (16). After the pollutant liquid pressurizedly penetrates for a period of time, sampling is performed from the frozen barrier (16) through the reserved sampling hole (14), the concentration of the pollutant is detected, and the penetration of the pollutant liquid in the frozen barrier (16) can be measured. Through the above-mentioned manner, pressure seepage can be performed to explore the ability of the artificial frozen soil barrier to block pollutants and the service life. In the application, the concentric spheres are used to maximize the seepage area and minimize the reverse seepage area, thereby maximizing the control of the seepage of the pollutant liquid. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The figure is a structural schematic diagram of the application;

[0023] Figure 2 The figure is a connection structure schematic diagram of the pressurization system of the application. DETAILED DESCRIPTION

[0024] The technical features of the present application are further described below in conjunction with the drawings and specific embodiments.

[0025] As shown in the drawings, the present application is a kind of pressure seepage device for simulating the migration of pollutants in frozen soil barrier, comprising a container shell (15), a seepage bin (19), a pollutant pressurized circulation device and a freeze-thaw incubator (4).

[0026] The container shell (15) is arranged in the freeze-thaw incubator (4), and the seepage bin (19) is installed in the container shell (15). The cavity of the container shell (15) is a spherical cavity, the outer wall of the seepage bin (19) is spherical, and the cavity of the container shell (15) and the outer wall of the seepage bin (19) are arranged as concentric spheres. The seepage holes are uniformly constructed on the outer wall of the seepage bin (19). The large ball of the container shell (15) and the small ball of the seepage bin (19) are filled with frozen barrier (16).

[0027] The liquid outlet pipe (20) and the liquid inlet pipe (21) pass through the support pipe (17), the end of the liquid outlet pipe (20) extends to the bottom of the seepage bin (19), which facilitates the removal of the contaminated liquid after the test. The liquid outlet pipe (20) and the liquid inlet pipe (21) are connected to the waste liquid recovery device (5) and the cold bath device (11) respectively, and the cold bath device (11) can provide constant temperature for the contaminated liquid. The pressurized delivery and extraction of the liquid outlet pipe (20) and the liquid inlet pipe (21) are operated through the pressurized system (10), and the valve one (8) for controlling the liquid flow in the liquid outlet pipe (20) is arranged in the middle of the liquid outlet pipe (20), and the valve two (9) for controlling the liquid flow in the liquid inlet pipe (21) is arranged in the middle of the liquid inlet pipe (21). The liquid outlet flow of the liquid outlet pipe (20) and the liquid inlet flow of the liquid inlet pipe (21) are controlled by the valve one (8) and the valve two (9) respectively.

[0028] The pressurized delivery and extraction of the liquid outlet pipe (20) and the liquid inlet pipe (21) are operated through the pressurizing system (10); the pressurizing system comprises a water pump group (101), a one-way valve (102), an accumulator pump (103), a water pressure gauge (104), a water pressure sensor (105), a pressure regulating valve (106), a backwater throttle valve (107), a water bath temperature controller (108), and a filter element (109); the filter element (109), the water bath temperature controller (108), the water pump group (101), and the one-way valve (102) are sequentially arranged on the liquid inlet pipe (21) along the liquid inlet direction of the liquid inlet pipe (21); the accumulator pump (103) is communicated with the liquid outlet pipe (20) through a pipeline, and the backwater throttle valve (107), the pressure regulating valve (106), the water pressure sensor (105), and the water pressure gauge (104) are sequentially arranged between the liquid inlet end of the liquid outlet pipe (20) and the accumulator pump (103) along the liquid outlet direction of the liquid outlet pipe (20). After the solution is cooled, the pressure is controlled through the pressure regulating valve 106 and the backwater throttle valve 107, the water pressure gauge 104 and the pressure sensor 105 are arranged on the hydraulic pipeline, and the real-time pressure of the solution can be collected through the pressure sensor 105.

[0029] The seepage bin (19), the frozen barrier (16), and the container shell (15) are arranged as concentric spheres. The large sphere is a cavity for limiting the shape of the frozen soil barrier (16) inside the container shell (15), the small sphere is provided with the seepage bin (19), and the space between the large sphere and the small sphere is the frozen soil barrier (16). Through the liquid outlet pipe (20) and the liquid inlet pipe (21), the pressurized contaminated liquid in the seepage bin (19) can seep into the frozen soil barrier, which can effectively avoid the flow around the contaminated liquid.

[0030] The seepage bin (19) is a storage and seepage device for the solution, and the support pipe (17) supports the seepage bin (19) to avoid extrusion and damage of the seepage bin (19) due to the self-weight pressure of the upper soil and the frost heaving pressure.

[0031] The support pipe (17) is filled with a heat preservation material with good heat preservation performance, which can avoid freezing of the liquid in the pipe during artificial freezing. The liquid outlet pipe 20 and the liquid inlet pipe 21 are also wrapped with a heat preservation material.

[0032] The outer wall of the container shell (15) can be a spherical surface. The cavity two of the seepage bin (19) can be a spherical cavity, which facilitates uniform seepage of the liquid in the seepage bin (19) to the surrounding.

[0033] In this embodiment, the temperature change in the frozen soil barrier (16) is monitored by collecting the temperature in the frozen soil barrier (16). The implementation is that the detection end of the temperature collector (2) is connected with the thermocouple, the thermocouple is placed in the frozen barrier (16), the output end of the temperature collector (2) is connected with the data input end of the electronic computer (1), the temperature in the frozen soil barrier (16) is collected by the temperature collector (2) and monitored by the electronic computer (1).

[0034] The support base (12) is arranged at the lower end of the container shell (15) and is fixed to the bottom of the container shell (15) by welding or bolt fixing. The lower end of the container shell (15) is provided with a through hole three for filling frozen soil. The middle part of the support base (12) is provided with a through hole four for filling frozen soil. After the support base (12) is installed at the lower end of the container shell (15), the through hole three is opposite to the through hole four, and the through hole three and the through hole four form a filling hole (22) for filling frozen soil into the container shell (15).

[0035] The container shell (15) is made of metal material with good heat conductivity. The sampling hole (14) is arranged on the surface of the container shell (15) according to the size and position as needed, so that sampling can be conveniently performed from the sampling hole (14) during the experiment. The filling hole (22) and the sampling hole (14) can be closed by using a piston.

[0036] In order to facilitate the installation of the seepage chamber (19) inside the container shell (15), the container shell (15) is arranged in the form of two hemispheres abutting each other. The flange is arranged at the abutting position of the two hemispheres and is fixed by bolts. When the seepage chamber (19) and the support pipe (17) are installed, the two hemispheres are opened, and then the two hemispheres are fixed by the flange and the bolts after installation.

[0037] The use steps of the pressurized seepage device for simulating the migration of pollutants in the frozen soil barrier in this embodiment are as follows:

[0038] I. Connect the thermocouple with the temperature collector (2) and the electronic computer (1), close the sampling hole (14) of the container shell (15), and check the sealing performance. Wrap the seepage chamber (19) with gauze to prevent the soil from being pressed into the seepage chamber (19) by self-weight pressure or frost heaving pressure. The soil sample is prepared according to the experimental scheme. After preparation, the soil sample is filled according to the size of the device. A thermocouple is placed at an appropriate position every certain distance in the lower half of the frozen soil barrier (16) to record the temperature change of the soil sample during freezing.

[0039] II. Close all valves, open the freeze mode of the freeze-thaw thermostat (4), set the freezing temperature, and open the temperature acquisition instrument (2) to collect temperature data. The thickness of the frozen soil is determined by the temperature data. When the temperature of the thermocouple changes little, the frozen soil barrier is basically stable.

[0040] III. Keep the freezing temperature, open the cold bath device (11), adjust the cold bath temperature, open valve two (9), and deliver the contaminated liquid to the infiltration chamber (19) through the pressurization system (10). After a period of time, pressurize the contaminated liquid to reach the specified pressure. The pressurization process can be continued by increasing the input flow and reducing the output flow, or increasing the input pressure, etc.

[0041] IV. Allow the contaminant to undergo a period of pressure infiltration. Stop the delivery of the contaminated liquid through the pressurization system (10), close valve two (9), and sample the frozen soil barrier (16) through the sampling hole (14). Then, save the samples layer by layer for concentration detection. After sampling through the sampling hole (14), backfill the sampling hole (14) with low-permeability material.

[0042] V. If the contaminant is detected in the outermost layer, the barrier is destroyed. If there is no contaminant or the contaminant is located farther from the outermost layer, continue to pressurize the infiltration, and then detect the concentration from another sampling hole after a period of time.

[0043] Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples. Changes, modifications, additions, or substitutions made by ordinary skilled persons within the essential scope of the present application should be within the protection scope of the present application.

Claims

1. A pressurized seepage device for simulating the transport of pollutants within a frozen soil barrier, characterized in that: include The container shell (15) and the freeze-thaw constant temperature chamber (4) are provided with a cavity inside the container shell (15) and a freezing barrier (16) is filled in the cavity. A reserved sampling hole (14) communicating with the cavity is constructed on the surface of the container shell (15). The seepage chamber (19) is fixedly installed in the cavity one of the container shell (15) and is wrapped by the freezing barrier (16); the inside of the seepage chamber (19) is constructed with a cavity two, and the surface of the seepage chamber (19) is constructed with seepage holes communicating with the cavity two. The pollutant pressurization and circulation device is connected to the cavity two of the seepage chamber (19) through a pipeline. The pollutant pressurization and circulation device pressurizes and injects pollutant liquid into the cavity two of the seepage chamber (19). The outer wall of the seepage chamber (19) is spherical, the cavity of the seepage chamber (19) is a spherical cavity, and the seepage holes are uniformly constructed on the outer wall of the seepage chamber (19); The outer wall of the container shell (15) is spherical, and the cavity of the container shell (15) is a spherical cavity; the seepage chamber (19) is located at the center of the cavity of the container shell (15); The outer shell of the container (15) is placed inside the freeze-thaw constant temperature chamber (4).

2. The pressurized seepage device for simulating pollutant transport within a frozen soil barrier according to claim 1, characterized in that: A support pipe (17) is provided between the container shell (15) and the seepage chamber (19). The support pipe (17) is a stainless steel pipe. The support pipe (17) passes through the top of the container shell (15) and is fixed to the container shell (15). One end of the support pipe (17) located inside the container shell (15) is fixedly connected to the seepage chamber (19).

3. The pressurized seepage device for simulating pollutant transport within a frozen soil barrier according to claim 1, characterized in that: The pollutant pressurized circulation device includes an outlet pipe (20), an inlet pipe (21), a waste liquid recovery device (5), and a cold bath device (11). One end of the outlet pipe (20) passes through the top of the container shell (15), the top of the seepage chamber (19) and extends to the lower part of the seepage chamber (19), and the other end of the outlet pipe (20) is connected to the waste liquid recovery device (5); One end of the liquid inlet pipe (21) passes through the top of the container shell (15), the top of the permeation chamber (19) and extends to the upper part of the permeation chamber (19), and the other end of the liquid inlet pipe (21) is connected to the cold bath device (11).

4. The pressurized seepage device for simulating pollutant transport within a frozen soil barrier according to claim 3, characterized in that: The middle section of the outlet pipe (20) is equipped with a valve 1 (8) to control the flow rate of liquid in the outlet pipe (20), and the middle section of the inlet pipe (21) is equipped with a valve 2 (9) to control the flow rate of liquid in the inlet pipe (21).

5. The pressurized seepage device for simulating pollutant transport within a frozen soil barrier according to claim 1, characterized in that: It also includes a temperature acquisition device (2), the detection end of which is located inside the freezing barrier (16).

6. The pressurized seepage device for simulating pollutant transport within a frozen soil barrier according to claim 3, characterized in that: The pressurized delivery and extraction of the liquid outlet pipe (20) and liquid inlet pipe (21) are operated by a pressurization system; the pressurization system includes a water pump group (101), a one-way valve (102), a storage pump (103), a water pressure gauge (104), a water pressure sensor (105), a pressure regulating valve (106), a return water throttling valve (107), a water bath thermostat (108), and a filter element (109); the filter element (109) and the water bath thermostat (108) are also mentioned. The water pump set (101) and the one-way valve (102) are arranged sequentially on the inlet pipe (21) along the inlet direction; the energy storage pump (103) is connected to the outlet pipe (20) through a pipeline; the return water throttling valve (107), the pressure regulating valve (106), the water pressure sensor (105), and the water pressure gauge (104) are arranged sequentially between the inlet end of the outlet pipe (20) and the energy storage pump (103) along the outlet direction.

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