Device and method for testing clogging mechanism of relief well under condition of bidirectional alternation of unclogging current and turbidity current

Abstract

The invention provides a device and a method for testing the clogging mechanism of a relief well under the condition of bidirectional alternation of unclogging current and turbidity current. The device comprises a test tank base, an organic glass tank fixed on the test tank base, a sample bottom support plate arranged at the bottom of the organic glass tank, a porous well pipe mounted on the sample bottom support plate, an inverted filter layer fixing frame mounted on the outer wall of the porous well pipe, and an inverted filter layer sample fixed in the inverted filter layer fixing frame, the inverted filter sample is divided into at least three parts by partition plate clamping grooves, a sample bottom support plate is supported on a test tank base by a bottom support plate annular bracket, a bottom water tank is formed between the sample bottom support plate and the test tank base, and clear water is introduced into the bottom water tank through a bottom water inlet pipe; the top of the porous well pipe is covered with a sample cover plate, the top of the organic glass groove is covered with a top fixing cover, and a top muddy water groove is formed between the sample cover plate and the top fixing cover and used for containing muddy water. According to the invention, test and quantitative analysis of the inverted filter clogging evolution process of the relief well can be realized.

Description

Technical Field

[0001] The invention relates to the field of test instruments and test methods, in particular to a device and method for testing the clogging mechanism of a pressure relief well under the condition of bidirectional alternation of clear and turbid flow. Background Art

[0002] Piping is the most common hazard of levees in the Yangtze River Basin during the flood season, accounting for more than 50% of the hazards during each flood, and its harm is huge. Pressure relief wells are one of the most effective measures to eliminate the hidden dangers of piping during the flood season of levee projects. Compared with other seepage control measures (such as vertical anti-seepage walls or single blown fill and cover measures), it has the advantages of significant effect, low cost, high flexibility, small footprint, and less impact on the environment. At present, levee pressure relief wells have played a huge role in flood control and disaster reduction in important dangerous sections of levees in my country.

[0003] In the prior art, the drainage and pressure relief effect of the dike pressure relief well is obvious in the initial stage of completion. As the service life is prolonged, the filter layer of the pressure relief well is prone to siltation, resulting in reduced permeability of the filter layer, which causes the flow of the pressure relief well to gradually decrease, or even complete failure, causing the danger of dike pipe burst to occur again. Although the pressure relief well with replaceable filter element has been developed in recent years, the wellhead of the pressure relief well is usually lower than the ground behind the dike, and it is difficult to form a wellhead closure. During non-flood season or flood season rainfall, muddy water is easy to flow back into the pressure relief well, which is easy to form siltation. Therefore, the siltation of the filter layer of the pressure relief well is an objective existence and difficult to avoid.

[0004] During the service of the embankment pressure relief well, whenever the water level of the outer river is high during the flood season (or flood period), the pressure relief well will automatically overflow with water, which is opposite to the direction of muddy water backflow. The overflowing groundwater is clean water, which has a reverse flushing effect on the filter layer blocked by backflow, which is equivalent to flushing with clean water to slow down the development of siltation. There is still a lack of research on this issue.

[0005] One method in the prior art is to use a test flume to inject muddy water in a siltation test study of a dike pressure relief well, and then test the permeability change of the filter material or filter layer to study the siltation mechanism of muddy water backflow;

[0006] One test in the prior art is a chemical clogging test, which mainly uses glucose water to continuously drip and immerse the filter layer of the background water body to test the chemical clogging substances and evolution process of the filter layer;

[0007] There is also a method of using a water tank to flow turbid water through the filter material or filter material, and then testing the clogging state or permeability of the filter material or material after the water supply is cut off.

[0008] In summary, the main problems existing in the existing clogging test devices and methods are:

[0009] 1. Conventional permeability test equipment cannot achieve the clean water reverse flushing effect, and cannot test and quantify the effect of clean water flushing the filter layer on siltation reduction throughout the process;

[0010] 2. The existing test equipment and methods cannot realize the modular installation of the filter layer, and cannot realize the quantitative analysis of the clogging state and degree of the filter layer during the test;

[0011] 3. When conventional testing instruments and methods are used, it is impossible to achieve the reverse intermittent alternating effects of muddy water and clean water on the filter layer during the test, and it is impossible to test the degree of clogging evolution of the filter layer under the coupling of the two effects.

[0012] Therefore, in the prior art, there is no device or method that can test and quantify the development and change process of filter layer clogging under the conditions of alternating reverse action of clear water and muddy water. Summary of the invention

[0013] In view of the above-mentioned defects or shortcomings in the prior art, the present invention provides a device and method for testing the clogging mechanism of pressure relief wells under the condition of two-way alternation of clear and turbid flow, which solves the shortcomings of the current common clogging test devices that cannot achieve the two-way alternation of clear and turbid water flow and cannot quantify the entire clogging process. The device and method have small size and are easy to install.

[0014] A device for testing the clogging mechanism of a pressure relief well under the condition of bidirectional alternation of clear and turbid flow comprises: a test tank base, an organic glass tank fixed to the test tank base, a sample bottom support plate arranged at the bottom of the organic glass tank, a porous well pipe installed on the sample bottom support plate, a filter layer fixing frame installed on the outer wall of the porous well pipe, and a filter layer sample fixed in the filter layer fixing frame, wherein the filter layer sample is divided into at least three parts by a partition plate slot, the sample bottom support plate is supported on the test tank base by a bottom support plate annular bracket, a bottom water tank is formed between the sample bottom support plate and the test tank base, and the bottom water tank is connected to clean water through a bottom water inlet pipe; the top of the porous well pipe is covered by a sample cover plate, the top of the organic glass tank is covered by a top fixed cover, a top turbid water tank is formed between the sample cover plate and the top fixed cover, and the top turbid water tank is used to connect turbid water.

[0015] Furthermore, it also includes a water outlet pipe connected to the bottom of the bottom water tank, the water outlet pipe is connected through the test tank base and is controlled by the water outlet pipe control valve.

[0016] Furthermore, the bottom water inlet pipe is connected to the side wall of the bottom water tank and is controlled by a bottom water inlet valve.

[0017] Furthermore, the side wall of the bottom water tank is connected to the bottom overflow pipe, and the bottom overflow pipe is provided with a bottom overflow valve.

[0018] Furthermore, it also includes a turbid water system connected to the top fixed cover, the turbid water system is controlled by a turbid water regulating valve to control water inlet, and the turbid water enters the organic glass tank through the turbid water system, the top fixed cover, and the top turbid water tank, and then enters the porous well pipe through the hole in the middle of the sample cover plate. The amount of turbid water inflow is regulated by the turbid water regulating valve.

[0019] Furthermore, the side wall of the top turbid water tank is connected to the top overflow pipe.

[0020] Furthermore, the filter layer sample is divided into 6 parts by partition grooves.

[0021] A method for testing the clogging mechanism of a pressure relief well under the condition of bidirectional alternation of clear and turbid flow, characterized in that the method is carried out using the above-mentioned device, and the method comprises the following steps:

[0022] Step 1: The turbid water in the turbid water system is mixed with mud and enters the porous well pipe through the turbid water regulating valve and the sample cover hole, and then flows into the filter layer sample. Part of the turbid water is filtered through the filter layer, and the mud is deposited in the filter layer sample. The turbid water regulating valve is closed, the sample cover is opened, and one of the filter layer samples in the partition card slot is taken out for quantitative analysis to obtain the turbid water clogging amount and water permeability attenuation of the filter layer sample at this time;

[0023] Step 2: During the test, the turbid water regulating valve, the outlet pipe control valve and the bottom overflow valve are closed. The clean water bottom inlet pipe is adjusted by the bottom inlet valve and enters the filter layer sample to form a backwashing effect. The water overflows from the top of the porous well pipe into the top overflow pipe overflow test system. The bottom inlet valve is closed, the sample cover is opened, and another filter layer sample in the partition card slot is taken out for quantitative analysis to obtain the turbid water clogging amount and water permeability attenuation of the filter layer sample at this time, and the influence of the clean water flushing time and number on the clogging amount and water permeability of the filter layer sample is quantitatively analyzed;

[0024] Step 3: Repeat steps 1 and 2 with different turbid water flow time, turbidity, clean water flow time and frequency, etc., until all the filter layer samples in the partition card slot are taken out for analysis, and obtain the relationship curve between a certain turbid water flow time, clean water flushing frequency or time and the permeability attenuation and clogging amount of the filter layer sample.

[0025] The present invention can test and quantitatively analyze the clogging evolution process of the filter layer of the dike pressure relief well under the action of muddy water backflow and clear water self-overflow flushing in the flood season. It has important value and significance for analyzing and predicting the effect and life of the dike pressure relief well, has good application prospects, and fills the gaps at home and abroad. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a test device for the clogging mechanism of a pressure relief well under the condition of bidirectional alternation of clear and turbid flow according to the present invention;

[0027] Figure 2 yes Figure 1 Sectional schematic diagram of part A;

[0028] Figure 3 yes Figure 1 Middle section B schematic diagram;

[0029] Figure 4 yes Figure 1 Schematic diagram of the structure of the sample cover;

[0030] Figure 5 yes Figure 1 Schematic diagram of the structure of the bottom support plate of the medium specimen.

[0031] Figure 6 The figure is a graph showing the relationship between the water permeability attenuation, muddy water clogging amount, and clean water flushing frequency and time of the filter layer sample according to the embodiment of the present invention.

[0032] In the figure: 1-plexiglass tank; 2-sample cover plate; 3-filter layer fixing frame; 4-porous well pipe; 5-filter layer sample; 6-partition slot; 7-sample bottom support plate; 8-bottom support plate ring bracket; 9-bottom water tank; 10-test tank base; 11-outlet pipe; 12-outlet pipe control valve; 13-bottom inlet pipe; 14-bottom inlet valve; 15-bottom overflow pipe; 16-bottom overflow valve; 17-top fixed cover; 18-top overflow pipe; 19-turbid water regulating valve; 20-turbid water system. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention.

[0034] Please refer to Figure 1-5 The embodiment of the present invention provides a device for testing the clogging mechanism of a pressure relief well under the condition of bidirectional alternation of clear and turbid flow, including a porous well pipe 4, a filter layer sample 5, a sample bottom support plate 7, a bottom support plate annular bracket 8, a bottom water tank 9, a test tank base 10, a water outlet pipe 11, a water outlet pipe control valve 12, a bottom water inlet pipe 13, a bottom water inlet valve 14, a bottom overflow pipe 15, a bottom overflow valve 16, a top fixed cover 17, a top overflow pipe 18, and a turbid water regulating valve 19.

[0035] Please also read Figure 3The filter layer sample 5 is fixed in the filter layer fixing frame 3 and attached to the outer wall of the porous well pipe 4. The filter layer sample 5 is divided into at least three parts by the partition slot 6. The porous well pipe 4 is connected to the sample bottom support plate 7, and the sample bottom support plate 7 is supported on the test tank base 10 by the bottom support plate annular bracket 8. The top of the porous well pipe 4 is covered by the sample cover plate 2 and then placed in the organic glass tank 1 as a whole. The organic glass tank 1 is installed on the test tank base 10, and a bottom water tank 9 is formed between the sample bottom support plate 7 and the test tank base 10. The water outlet pipe 11 connected to the bottom of the bottom water tank 9 is connected through the test tank base 10 and is controlled by the water outlet pipe control valve 12. The bottom water inlet pipe 13 is connected to the side wall of the bottom water tank 9 and is controlled by the bottom water inlet valve 14. The bottom overflow pipe 15 is connected to the other side wall of the bottom water tank 9 and is controlled by the bottom overflow valve 16; the top of the organic glass tank 1 is covered by a top fixed cover 17, and a top turbid water tank is formed between the sample cover plate 2 and the top fixed cover 17. The side wall of the top turbid water tank is connected to the top overflow pipe 18, and the turbid water system 20 is connected to the top fixed cover 17 and is controlled by the turbid water regulating valve 19.

[0036] The embodiment of the present invention also provides a method for testing the clogging mechanism of a relief well under the condition of bidirectional alternation of clear and turbid flow, which is carried out using the above-mentioned device. The method comprises the following steps:

[0037] Step 1: The turbid water mixed with mud in the turbid water system 20 enters the porous well pipe 4 through the turbid water regulating valve 19 and the holes of the sample cover plate 2, and then flows into the filter layer sample 5. Part of the turbid water is filtered through the filter layer, and the mud is deposited in the filter layer sample 5. During the test, the filter layer sample 5 will have water permeability attenuation due to clogging. In order to quantitatively analyze the turbid water clogging amount in the filter layer sample and the degree of water permeability attenuation of the filter layer test, the turbid water regulating valve 19 can be closed, the sample cover plate 2 can be opened, and one of the filter layer samples 5 in the partition card slot 6 can be taken out for quantitative analysis to obtain the turbid water clogging amount and water permeability attenuation of the filter layer sample 5 at this time;

[0038] Step 2: In order to analyze the flushing effect of the overflow pressure relief well of the high water level pressure relief well during flood or flood season on siltation, the turbid water regulating valve 19, the outlet pipe control valve 12 and the bottom overflow valve 16 are closed during the test, and the clean water bottom water inlet pipe 13 is adjusted by the bottom water inlet valve 14 and enters the filter layer sample 5 to form a backwashing effect. The water overflows from the top of the porous well pipe 4 and enters the top overflow pipe 18 to overflow the test system. In order to quantitatively analyze the influence of the duration and number of clean water flushing on the siltation amount and water permeability of the filter layer sample 5, the bottom water inlet valve 14 can be closed, the sample cover plate 2 can be opened, and another filter layer sample 5 in the partition card slot 6 can be taken out for quantitative analysis to obtain the turbid water siltation amount and water permeability attenuation of the filter layer sample 5 at this time;

[0039] Step 3: According to the needs of quantitative analysis, different turbid water flow time, turbidity; clean water flow time, frequency, etc. can be used to repeat step 1 and step 2 until all 6 filter layer samples 5 in the partition card slot 6 are taken out for analysis, and the relationship curve between a certain turbid water flow time, clean water flushing frequency or time and the permeability attenuation and siltation amount of the filter layer sample 5 can be obtained, see Figure 6 .

[0040] The present invention can finally obtain a curve diagram showing the relationship between the water permeability attenuation, muddy water clogging amount, and clean water flushing frequency and time of the filter layer sample 5, as shown in FIG. Figure 6 shown.

[0041] The present invention is mainly used to study the clogging of turbid water backflow in dike pressure relief wells and the self-overflow flushing of clear water in flood season, and to reveal the clogging evolution mechanism of the filter layer of the pressure relief wells. It has important value and significance for quantitative test analysis and prediction of the effect and life of the pressure relief wells, and also provides theoretical and support for flood control and disaster reduction of dikes, and has good application prospects.

[0042] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A device for testing the clogging mechanism of pressure relief wells under the condition of alternating clear and turbid flow in both directions, characterized in that: include: A test tank base (10), an organic glass tank (1) fixed to the test tank base (10), a sample bottom support plate (7) arranged at the bottom of the organic glass tank (1), a porous well pipe (4) installed on the sample bottom support plate (7), a filter layer fixing frame (3) installed on the outer wall of the porous well pipe (4), and a filter layer sample (5) fixed in the filter layer fixing frame (3), wherein the filter layer sample (5) is divided into at least three parts by a partition plate slot (6), and the sample bottom support plate (7) is composed of a bottom The support plate annular bracket (8) is supported on the test tank base (10); a bottom water tank (9) is formed between the sample bottom support plate (7) and the test tank base (10); the bottom water tank (9) is connected to clean water through a bottom water inlet pipe (13); the top of the porous well tube (4) is covered by a sample cover plate (2); the top of the organic glass tank (1) is covered by a top fixed cover (17); a top turbid water tank is formed between the sample cover plate (2) and the top fixed cover (17); the top turbid water tank is used to connect turbid water.

2. The device for testing the clogging mechanism of pressure relief wells under the condition of bidirectional alternation of clear and turbid flow as claimed in claim 1, characterized in that: It also includes a water outlet pipe (11) connected to the bottom of the bottom water tank (9). The water outlet pipe (11) is connected to the test tank base (10) and is controlled by a water outlet pipe control valve (12).

3. The device for testing the clogging mechanism of pressure relief wells under the condition of bidirectional alternation of clear and turbid flow as claimed in claim 1, characterized in that: The bottom water inlet pipe (13) is connected to the side wall of the bottom water tank (9) and is controlled by a bottom water inlet valve (14).

4. The device for testing the clogging mechanism of pressure relief wells under the condition of bidirectional alternation of clear and turbid flow as claimed in claim 1, characterized in that: The side wall of the bottom water tank (9) is connected to a bottom overflow pipe (15), and a bottom overflow valve (16) is provided on the bottom overflow pipe (15).

5. The device for testing the clogging mechanism of pressure relief wells under the condition of bidirectional alternation of clear and turbid flow as claimed in claim 1, characterized in that: It also includes a turbid water system (20) connected to the top fixed cover (17), wherein the turbid water system (20) is controlled by a turbid water regulating valve (19) to control water inlet. The turbid water enters the organic glass tank (1) through the turbid water system (20), the top fixed cover (17), and the top turbid water tank, and then enters the porous well pipe (4) through the hole in the middle of the sample cover plate (2). The amount of turbid water inflow is regulated by the turbid water regulating valve (19).

6. The device for testing the clogging mechanism of pressure relief wells under the condition of bidirectional alternation of clear and turbid flow as claimed in claim 1, characterized in that: The side wall of the top turbid water tank is connected to the top overflow pipe (18).

7. The device for testing the clogging mechanism of pressure relief wells under the condition of bidirectional alternation of clear and turbid flow as claimed in claim 1, characterized in that: The filter layer sample (5) is divided into six parts by the partition plate slot (6).

8. A method for testing the clogging mechanism of pressure relief wells under the condition of alternating clear and turbid flow in both directions, characterized in that: The method is carried out using the device according to any one of claims 1 to 7, and comprises the following steps: Step 1: The turbid water in the turbid water system (20) is mixed with mud and enters the porous well pipe (4) through the turbid water regulating valve (19) and the holes of the sample cover plate (2), and then flows into the filter layer sample (5). Part of the turbid water is filtered through the filter layer, and the mud is deposited in the filter layer sample (5). The turbid water regulating valve (19) is closed, the sample cover plate (2) is opened, and one of the filter layer samples (5) in the partition card slot (6) is taken out for quantitative analysis to obtain the turbid water clogging amount and permeability attenuation amount of the filter layer sample (5) at this time; Step 2: During the test, the turbid water regulating valve (19), the outlet pipe control valve (12) and the bottom overflow valve (16) are closed, and the clean water bottom inlet pipe (13) is regulated by the bottom inlet valve (14) and enters the filter layer sample (5) to form a backwashing effect. The water overflows from the top of the porous well pipe (4) and enters the top overflow pipe (18) to overflow the test system. The bottom inlet valve (14) is closed, the sample cover (2) is opened, and another filter layer sample (5) in the partition card slot (6) is taken out for quantitative analysis to obtain the turbid water clogging amount and water permeability attenuation of the filter layer sample (5) at this time, and quantitatively analyze the influence of the clean water flushing time and number of times on the clogging amount and water permeability of the filter layer sample (5); Step 3: Repeat the test of steps 1 and 2 with different turbid water flow time, turbidity, clean water flow time, frequency, etc. until all the filter layer samples (5) in the partition plate slot (6) are taken out for analysis, and obtain the relationship curve between a certain turbid water flow time, clean water flushing frequency or time and the permeability attenuation and siltation amount of the filter layer sample (5).

Images