A device and method for testing the plugging mechanism of a pressure-reducing well under bidirectional and alternating clear and turbid flow conditions

Abstract

The application provides a device and method for testing the plugging mechanism of a pressure-reducing well under the condition of bidirectional and alternate clear water and turbid water, which comprises a test tank base, a plexiglass tank fixed to the test tank base, a sample bottom support plate arranged at the bottom of the plexiglass tank, a multi-hole well pipe installed on the sample bottom support plate, a filter layer fixing frame installed on the outer wall of the multi-hole well pipe, and a filter layer sample fixed in the filter layer fixing frame. The filter layer sample is divided into at least three parts by a partition slot. The sample bottom support plate is supported on the test tank base by a bottom support plate annular support, and a bottom water tank is formed between the sample bottom support plate and the test tank base. The bottom water tank is connected to clear water through a bottom water inlet pipe. The top of the multi-hole well pipe is covered by a sample cover plate, and the top of the plexiglass 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 for connecting to turbid water. The application can realize the test and quantitative analysis of the plugging evolution process of the filter layer of the pressure-reducing well.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of experimental instruments and experimental methods, and particularly relates to a kind of silt flow bidirectional alternate condition under the clogging mechanism test device and method of pressure relief well. BACKGROUND

[0002] Dyke piping is the most common danger of dyke in flood season in Yangtze River Basin, and accounts for more than 50% of the proportion of danger during flood period, which is very harmful. Pressure relief well is one of the most effective measures to eliminate piping danger in flood season for current dyke engineering. Compared with other seepage control measures (such as vertical cutoff wall or single dredger cover), it has the advantages of significant effect, low cost, great flexibility, small occupation, and less impact on environment. At present, dyke pressure relief well has played a huge benefit in flood control and disaster reduction in important dyke danger sections in China.

[0003] In the prior art, the drainage pressure reduction effect of dyke pressure relief well is obvious at the initial stage of completion, and with the extension of service, the filter layer of the pressure relief well is prone to clogging, which reduces the permeability of the filter layer and causes the flow of the pressure relief well to gradually decrease, and even completely fails, so that the dyke piping danger occurs again. Although the filter core replaceable pressure relief well has been developed in recent years, the well mouth of the pressure relief well is usually lower than the ground behind the dyke, and it is difficult to form a closed well mouth, so muddy water is easy to flow into the pressure relief well during non-flood season or rainfall in flood season, and clogging is easy to occur. Therefore, the filter layer clogging of the pressure relief well is objective and difficult to avoid.

[0004] During the service process of the dyke pressure relief well, the pressure relief well will automatically overflow water when the water level of the outer river is high during flood season (or flood period), which is opposite to the direction of the muddy water flowing into the pressure relief well. The self-overflowing groundwater belongs to clear water, which has a reverse flushing effect on the filter layer with backflow clogging, which is equivalent to clear water flushing to slow down the development of clogging. The research on this problem is still blank.

[0005] In the prior art, one method is to inject muddy water into a test tank during the clogging test research of the dyke pressure relief well, and then test the permeability change of the filter material or filter layer, so as to study the muddy water backflow clogging mechanism.

[0006] One test in the prior art belongs to chemical clogging test, which mainly uses glucose water to continuously drip and soak the filter layer in the background water body, and tests the chemical clogging substances and evolution process of the filter layer.

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

[0008] In summary, the existing problems of the clogging test device and method are mainly as follows:

[0009] 1. The conventional permeability test equipment cannot realize the reverse flushing effect of clear water, and cannot test and quantify the influence of clear water flushing on filter layer clogging in the whole process.

[0010] 2. Existing test equipment and methods cannot achieve modular installation of the filter layer, and cannot achieve quantitative analysis of the filter layer clogging status and degree during the test;

[0011] 3. When conventional testing instruments and methods are used, it is impossible to achieve the reverse intermittent alternating effect of muddy water and clear 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 equipment 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 deficiencies in the prior art, the present invention provides a device and method for testing the clogging mechanism of pressure relief wells under the conditions of bidirectional alternation of clear and turbid flow, which solves the shortcomings of the current common clogging test devices that cannot achieve bidirectional alternation of clear and turbid water flow and cannot quantitatively test the entire clogging process. It has a small size and is easy to install.

[0014] A device for testing the clogging mechanism of a pressure relief well under conditions of bidirectional alternating 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. The filter layer sample is divided into at least three parts by a partition 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. Clean water is introduced into the bottom water tank through a bottom water inlet pipe. The top of the porous well pipe is covered by a sample cover plate, and the top of the organic glass tank is covered by a top fixing cover. A top turbid water tank is formed between the sample cover plate and the top fixing cover. The top turbid water tank is used to receive 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 the water inlet, the turbid water passes through the turbid water system, the top fixed cover, and the top turbid water trough into the organic glass 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 adjusted by the turbid water regulating valve.

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

[0020] Further, the anti-filter layer sample is divided into six parts by the partition card slot.

[0021] A method for testing the plugging mechanism of a pressure relief well under the condition of bidirectional alternating clear and turbid water flow, characterized in that the above device is used, and the method comprises the following steps:

[0022] Step 1: The turbid water in the turbid water system is mixed with the mud, enters the multi-hole well pipe through the turbid water adjusting valve through the sample cover plate hole, and then flows into the anti-filter layer sample. Part of the turbid water is filtered through the anti-filter layer, and the mud is accumulated in the anti-filter layer sample. The turbid water adjusting valve is closed, the sample cover plate is opened, one of the anti-filter layer samples in the partition card slot is taken out, and quantitative analysis is performed to obtain the turbid water plugging amount and the water permeability attenuation amount of the anti-filter layer sample at this time.

[0023] Step 2: In the test, the turbid water adjusting valve, the water outlet pipe control valve and the bottom overflow valve are closed, the clear water bottom inlet pipe is adjusted through the bottom inlet valve, the anti-washing effect is formed in the anti-filter layer sample, the water is overflowed into the top overflow pipe through the top overflow pipe, and the test system is overflowed. The bottom inlet valve is closed, the sample cover plate is opened, the other anti-filter layer sample in the partition card slot is taken out, and quantitative analysis is performed to obtain the turbid water plugging amount and the water permeability attenuation amount of the anti-filter layer sample at this time. The influence of the clear water flushing time and frequency on the plugging amount and the water permeability of the anti-filter layer sample is quantitatively analyzed.

[0024] Step 3: Different turbid water water passing time, turbidity, clear water water passing time and frequency are used to repeat steps 1 and 2 until all the anti-filter layer samples in the partition card slot are taken out and analyzed. The relationship curve between the turbid water water passing time, the clear water flushing frequency or time and the water permeability attenuation and the plugging amount of the anti-filter layer sample is obtained.

[0025] The present application can realize the test and quantitative analysis of the plugging evolution process of the anti-filter layer of the pressure relief well under the conditions of turbid water backflow plugging and clear water self-overflow flushing in the flood season. It has important value and significance for analyzing and predicting the effect and service life of the pressure relief well of the dike, and has good application prospect, and fills the blank at home and abroad. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a structural schematic view of the pressure relief well plugging mechanism test device under the condition of bidirectional alternating clear and turbid water flow of the present application;

[0027] Figure 2 is Figure 1 is a sectional view of part A in the present application;

[0028] Figure 3 is Figure 1 is a sectional view of part B in the present application;

[0029] Figure 4 is Figure 1 Structure diagram of the sample cover plate in the pilot test;

[0030] Figure 5 is Figure 1 Structure diagram of the sample bottom support plate in the pilot test.

[0031] Figure 6 The relationship curve between the water permeability attenuation of the anti-filtration layer sample, the silted amount of turbid water and the flushing frequency and time of the sample according to the embodiment of the application.

[0032] In the figure: 1 - organic glass tank; 2 - sample cover plate; 3 - anti-filtration layer fixing frame; 4 - porous well pipe; 5 - anti-filtration layer sample; 6 - partition card slot; 7 - sample bottom support plate; 8 - bottom support plate annular support; 9 - bottom water tank; 10 - test tank base; 11 - water outlet pipe; 12 - water outlet pipe control valve; 13 - bottom water inlet pipe; 14 - bottom water 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 solutions in the application will be described clearly and completely below in combination with the drawings in the application.

[0034] Please refer to Figures 1-5 The embodiment of the application provides a test device for the plugging mechanism of a reduced pressure well under the condition of bidirectional and alternate clear water and turbid water, which comprises a porous well pipe 4, an anti-filtration layer sample 5, a sample bottom support plate 7, a bottom support plate annular support 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 refer to Figure 3The anti-filter layer sample 5 is fixed in the anti-filter layer fixing frame 3 and adheres to the outer wall of the porous well pipe 4, and the anti-filter layer sample 5 is divided into at least three parts by the partition card slot 6. The porous well pipe 4 is connected with the sample bottom support plate 7, the sample bottom support plate 7 is supported on the test tank base 10 by the bottom support plate annular support 8, the top of the porous well pipe 4 is covered by the sample cover plate 2 and then is placed in the organic glass tank 1 as a whole. The organic glass tank 1 is installed on the test tank base 10, and the sample bottom support plate 7 and the test tank base 10 form the bottom water tank 9, the water outlet pipe 11 which is communicated with the bottom of the bottom water tank 9 is connected out of the test tank base 10 and is controlled by the water outlet pipe control valve 12, the bottom water inlet pipe 13 is connected with 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 with 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 the top fixing cover 17, the sample cover plate 2 and the top fixing cover 17 form the top turbid water tank, the side wall part of the top turbid water tank is connected with the top overflow pipe 18, the turbid water system 20 is connected with the top fixing cover 17 and is controlled by the turbid water adjusting valve 19.

[0036] The embodiment of the present application also provides a kind of under pressure well jamming mechanism test method under the condition of clear turbid flow bidirectional alternation, it is carried out using above device, and the method comprises the following steps:

[0037] Step 1: muddy water in turbid water system 20 is mixed with mud, enters porous well pipe 4 through sample cover plate 2 hole via turbid water adjusting valve 19, then flows into anti-filter layer sample 5, part of muddy water is filtered by anti-filter layer, mud is deposited in anti-filter layer sample 5, and anti-filter layer sample 5 will be attenuated in permeability due to jamming in test process, in order to quantitatively analyze muddy water jamming amount in anti-filter layer sample and attenuation degree of permeability of anti-filter layer test, turbid water adjusting valve 19 can be closed, sample cover plate 2 is opened, and one of anti-filter layer sample 5 in partition card slot 6 is taken out to carry out quantitative analysis to obtain muddy water jamming amount and permeability attenuation amount of anti-filter layer sample 5 at this time.

[0038] Step 2: in order to analyze the washing effect of under pressure well overflow on jamming of under pressure well in flood or high water level period, turbid water adjusting valve 19, water outlet pipe control valve 12 and bottom overflow valve 16 are closed in test, clear water bottom water inlet pipe 13 is adjusted by bottom water inlet valve 14, enters anti-filter layer sample 5 to form backwashing effect, water is overflowed into top overflow pipe 18 through the top of porous well pipe 4 and is overflowed from test system, in order to quantitatively analyze the influence of clear water washing time, frequency and the like on jamming amount and permeability of anti-filter layer sample 5, bottom water inlet valve 14 can be closed, sample cover plate 2 is opened, and another anti-filter layer sample 5 in partition card slot 6 is taken out to carry out quantitative analysis to obtain muddy water jamming amount and permeability attenuation amount of anti-filter layer sample 5 at this time.

[0039] Step 3: According to the needs of quantitative analysis research, different turbid water passing time, turbidity, clear water passing time and frequency can be used to repeat steps 1 and 2 until the 6 anti-filtration layer samples 5 in the partition card slot 6 are all taken out for analysis, that is, the relationship curve of certain turbid water passing time, clear water flushing frequency or time and the water permeability attenuation and siltation amount of the anti-filtration layer sample 5 can be obtained, see Figure 6 .

[0040] The application finally obtains the relationship curve diagram of the water permeability attenuation of the anti-filtration layer sample 5, the muddy water siltation amount and the clear water flushing frequency and time, as shown in Figure 6 .

[0041] The application is mainly used for studying the muddy water backflow siltation of the dike pressure relief well and the self-overflow flushing effect of clear water in the flood season, revealing the siltation evolution mechanism of the anti-filtration layer of the pressure relief well, and has important value and significance for quantitative test analysis and prediction of the effect and service life of the pressure relief well, and provides theory and support for dike flood control and disaster reduction, and has good application prospect.

[0042] The above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto, any change or replacement within the technical range disclosed by the application can be easily thought by any person skilled in the art, which should be covered in the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A device for testing the clogging mechanism of relief wells under conditions of alternating clear and turbid flow, 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) provided 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 slot (6), and the sample bottom support plate (7) is provided at the bottom. The support plate annular bracket (8) is supported 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), and the bottom water tank (9) is connected to clean water through the bottom water inlet pipe (13); the top of the porous well pipe (4) is covered by the sample cover plate (2), and the top of the organic glass tank (1) is covered by the top fixed cover (17), and a top turbid water tank is formed between the sample cover plate (2) and the top fixed cover (17), and the top turbid water tank is used to connect turbid water.

2. The device for testing the clogging mechanism of relief wells under conditions of alternating 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 through the test tank base (10) and is controlled by the water outlet pipe control valve (12).

3. The device for testing the clogging mechanism of relief wells under conditions of alternating 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 relief wells under conditions of alternating 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 relief wells under conditions of alternating clear and turbid flow as claimed in claim 1, characterized in that: The invention 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). The turbid water passes through the turbid water system (20), the top fixed cover (17), and the top turbid water tank and enters the organic glass tank (1). Then, the turbid water enters the porous well pipe (4) through the hole in the middle of the sample cover plate (2). The amount of turbid water flowing in is regulated by the turbid water regulating valve (19).

6. The device for testing the clogging mechanism of relief wells under conditions of alternating 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 relief wells under conditions of alternating 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 relief wells under conditions of alternating clear and turbid flow, 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 flows through the turbid water regulating valve (19) and the sample cover (2) hole into the porous well pipe (4), 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 (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) into the top overflow pipe (18) and overflows 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 permeability attenuation amount 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 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 card 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 clogging amount of the filter layer sample (5).

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