Test method and device for simulating riverbed percolation and water collection

Abstract

The invention relates to a set of test method for simulating riverbed percolation water collection, which adopts a set of test device for simulating riverbed percolation water collection, and comprises the following steps: S1, primarily selecting various filter material types and thicknesses meeting engineering requirements through a calibration test; s2, selecting the type, thickness and combination sequence of the inverted filter material, and verifying through a simple simulation test to form an inverted filter material design scheme; and S3, arranging the selected filter materials in a simulation test box device according to the selected thickness and combination sequence, simulating the upper river water flow velocity, carrying out large-scale test analysis, and verifying whether the design scheme of the filter materials meets the engineering requirements or not. The test device for simulating riverbed percolation and water collection comprises a calibration test column device, a simulation test column device and a simulation test box device. According to the application, the actual operation effect of the selected inverted filter can be verified through a set of indoor tests, a basis is provided for the design of the inverted filter of the water collecting gallery, and the problems existing in the arrangement of the existing percolation water collecting inverted filter are solved.

Description

Technical Field

[0001] The present application relates to the field of municipal water supply and drainage, and specifically to a set of test methods and devices for simulating riverbed infiltration and water extraction. Background Art

[0002] Riverbed infiltration water extraction involves burying a water collection corridor within the riverbed gravel. As the river water (or riverbed undercurrent) partially seeps through the water collection corridor, the turbidity of the water gradually decreases due to the filtering effect of the riverbed gravel, and the water eventually flows into the water collection corridor. Based on the operational experience of similar domestic projects, the key to the success of riverbed infiltration water extraction lies in the gravel filter layer installed around the water collection corridor. The filter layer must first have a certain filtering and turbidity removal function, capable of filtering the river's high turbidity water during rainy and flood periods into low-turbidity water. At the same time, the filter layer must also have a certain water permeability, that is, it must be able to meet the water intake requirements and avoid excessive siltation in the filter layer due to the collection of high turbidity water during rainy and flood periods, thereby affecting the water collection capacity of the water collection corridor. The turbidity removal and water permeability functions of the sand and gravel filter layer around the water collection corridor are contradictory. Generally speaking, the larger the particle size of the sand and gravel in the filter layer, the stronger its water permeability, but the worse the turbidity removal effect; conversely, the smaller the particle size of the sand and gravel in the filter layer, the better its turbidity removal effect, but the lower its water permeability.

[0003] Chinese patent CN113404121A proposes a natural riverbed infiltration water extraction integrated system and its design method. The natural riverbed infiltration water extraction integrated system is an integrated water extraction system formed by arbitrarily combining at least two water extraction methods including tube well water extraction, large well water extraction, radial well water extraction, infiltration channel water extraction, sunken artificial filter water extraction, and reverse infiltration water extraction. The present invention selects two or more water extraction methods based on the actual conditions of the natural riverbed to combine into a new type of system water extraction method, thereby realizing efficient, low-cost, and large-scale exploitation of natural riverbed subsurface water. The integrated system is suitable for river sections with various complex geological conditions. It mainly breaks the limitations of traditional, single water extraction methods on geological conditions and construction conditions, effectively expands water production, and ensures excellent water quality. Through sensors and Internet of Things technology, it works in conjunction with the control backwash system to form a highly automated integrated water extraction system. However, the design of its sand and gravel filtration is based on the practical experience of similar engineering operations. No systematic physical model test research has been conducted on the infiltration and water intake effect of the sand and gravel filtration layer. As a result, the water quality of the water collection corridor is too high due to improper setting of the surrounding filtration layer, or the filtration layer is excessively silted up in a short period of time, affecting the water collection volume. Summary of the Invention

[0004] This application provides a set of physical test methods and devices for simulating riverbed infiltration and water extraction, which can test the turbidity removal effect and water permeability of a sand and gravel filter layer composed of filter materials of different particle sizes and thicknesses, and can simulate the operation of the selected filter layer under the actual operation scenario of the project, providing an experimental basis for the design of infiltration and water collection projects.

[0005] To achieve the above objectives, this application adopts the following technical solutions:

[0006] A test method for simulating riverbed infiltration and water collection includes the following steps:

[0007] S1. Use the calibration test column device to test the filtration and turbidity removal capabilities of filter media of different particle sizes and thicknesses, and preliminarily select the types and thicknesses of filter media that meet the project needs through the test;

[0008] S2. Combine various filter materials that meet the project requirements after preliminary selection through testing and load them into a simulated test column device. Test the overall infiltration and water extraction function of the combined materials to select the type, thickness, and combination order of the filter materials and form a filter material design plan.

[0009] S3. Install the selected various filter materials in the simulation test box according to the selected thickness and combination order, simulate the upper river flow rate, conduct test analysis, and verify whether the filter material design scheme meets the project needs.

[0010] Furthermore, the specific steps of S1 are as follows: first, the filter material to be tested for turbidity removal ability is loaded into the calibration test column device. To improve the test efficiency, two calibration test columns can be loaded with different types of filter materials and tested at the same time; by adding soil and water into the water supply tank and stirring with a calibration stirrer to prepare test water with different turbidities, the water is then pumped into the calibration test column by a calibration submersible pump, and after the overflow stabilizes, the timing is started and water samples are taken in sequence. Different heights of the calibration test column represent different thicknesses of the filter material. During the test, water samples are taken at intervals of 2 minutes, 5 minutes and 10 minutes along different heights of the calibration test column, and then the sampling interval is always 10 minutes until the turbidity of the outlet water stabilizes and sampling is stopped, the turbidity detection data is recorded, and a statistical chart is formed; by analyzing the calibration test charts of various filter materials, the turbidity removal ability of different filter materials under different thickness conditions is obtained, and combined with the water intake turbidity requirements required by the project, various filter material types and thicknesses that meet the project needs are preliminarily selected.

[0011] Furthermore, the specific steps of S2 are as follows: first, the various preliminarily selected filter materials are combined according to different thicknesses and sequentially loaded into the simulation test column device; after the test starts, the simulated stirrer stirs the simulated water supply tank to form test water of different turbidities, and keeps the solution concentration stable, the simulated submersible pump is connected to the simulation test column for water supply, the simulated submersible pump pump speed is adjusted to stabilize the water supply flow rate and flow rate, and the flow rate of the simulated peristaltic pump is adjusted to be the same as that of the simulated submersible pump, and the simulated water outlet at the bottom of the second simulation test column is tested for turbidity and water volume every 2 minutes, 5 minutes and 10 minutes, and then the sampling interval is always 10 minutes until the turbidity and water volume of the water outlet are stable, and the test is stopped, the turbidity detection data and water volume data are recorded, and statistical charts are formed; by analyzing the charts, it is judged whether the preliminarily selected filter material design scheme meets the project needs. If it does not meet the requirements, the filter material particle size and thickness are adjusted, and the test is repeated; the type, thickness and combination order of the filter material are selected through the simulation test column test;

[0012] The overall infiltration water intake function described in S2 includes the water quality and water quantity of the intake water.

[0013] Furthermore, the specific steps of S3 are:

[0014] First, the selected various filter materials are combined according to the planned thickness and loaded into the simulation test chamber device in sequence; after the test starts, the test chamber agitator stirs the test chamber water supply tank to form test water with different turbidities and maintain a stable solution concentration; the test chamber submersible pump water supply is connected to the simulation test chamber, and the pump speed of the test chamber submersible pump is adjusted to stabilize the water supply flow rate and flow rate. At the same time, the opening of the water inlet of the first simulation test chamber is adjusted so that the water flow on the top surface of the filter material in the test chamber reaches the design flow rate, and the pump speed of the peristaltic pump of the test chamber is adjusted so that the water levels in the two test chambers can be kept stable respectively. The turbidity and water volume of the outlet water are tested at the water outlet at the bottom of the second simulation test chamber every 2 minutes, 5 minutes and 10 minutes, and then the sampling interval is always 10 minutes. The test is stopped until the turbidity and water volume of the outlet water are stable, and the turbidity test data and water volume data are recorded and statistical charts are formed; by analyzing the charts, it is verified whether the filter material design scheme meets the project needs.

[0015] A test device for simulating riverbed infiltration and water collection, including a calibration test column device;

[0016] The calibration test column device includes two calibration test columns and a calibration water supply tank. The calibration test columns are provided with calibration water outlets, which are arranged at intervals, and a calibration water inlet is provided on the top. The calibration water supply tank is provided with a calibration agitator and a calibration submersible pump, and the calibration submersible pump is connected to the two calibration water inlets respectively through a calibration water inlet pipe.

[0017] Preferably, the calibration test column is marked with scales at different heights, and each calibration test column has at least two calibration outlets. The height difference between the two calibration outlets can be obtained by observing the scales to facilitate sampling of water outlets from filter layers of different thicknesses.

[0018] Preferably, according to the order of use, after the calibration test column device is used, the simulation test column device is also used;

[0019] The simulation test column device includes two simulation test columns and a simulation water supply tank. The bottom of the simulation test column is provided with a simulation water outlet, and the top is provided with a simulation water inlet. The simulation water supply tank is provided with a simulation stirrer and a simulation submersible pump.

[0020] The two simulation test columns are respectively a first simulation test column and a second simulation test column;

[0021] The simulated submersible pump is connected to the simulated water inlet of the first simulated test column through a simulated water inlet pipe, and the simulated water outlet at the bottom of the first simulated test column is connected to the simulated water inlet of the second simulated test column through a simulated connecting pipe.

[0022] Preferably, a simulated peristaltic pump is provided on the simulated connecting pipe between the first simulated test column and the second simulated test column, and scales are marked at different heights along the simulated test column to facilitate marking the thickness of each layer of filter material in the test column.

[0023] Preferably, according to the order of use, after using the simulation test column device, the simulation test box device is also used;

[0024] The simulation test chamber device includes two simulation test chambers and a test chamber water supply tank. The two simulation test chambers are respectively a first simulation test chamber and a second simulation test chamber. The first simulation test chamber is provided with a test chamber water outlet and a test chamber water inlet. The test chamber water supply tank is provided with a test chamber agitator and a test chamber submersible pump.

[0025] The test box submersible pump is connected to the test box water inlet of the first simulation test box through the test box water inlet pipe, and the test box water outlet of the first simulation test box is connected to the test box water inlet of the second simulation test box through the test box connecting pipe;

[0026] The size of the simulation test box is larger than that of the simulation test column.

[0027] Preferably, a test box peristaltic pump is provided on the test box connecting pipe between the first simulation test box and the second simulation test box, and scales are marked at different heights on the upper edges of the first simulation test box and the second simulation test box to facilitate marking the thickness of each layer of filter material in the first simulation test box and the second simulation test box;

[0028] A water outlet is provided on the top of the first simulation test box opposite to the water inlet of the test box, and the elevation of the water outlet is lower than the water inlet of the test box;

[0029] The water inlet of the second simulation test chamber is provided with no less than two water inlet branches in parallel.

[0030] Beneficial effects of the present invention:

[0031] At present, there are many engineering cases in China that use riverbed water collection corridors for infiltration water extraction, but the design of their sand and gravel filtration is based on the practical experience of similar engineering operations. There has been no systematic physical model test research on the infiltration water extraction effect of the sand and gravel filtration layer, resulting in the water collection corridor having excessive turbidity due to improper setting of the surrounding filtration layer, or the filtration layer being excessively silted up in a short period of time, thereby affecting the water collection volume. This application can verify the actual operating effect of the selected filtration layer in the laboratory, provide a basis for the design of the filtration layer of the water collection corridor, and solve the current problem that the turbidity of the water collected in the water collection corridor is too high due to improper setting of the surrounding filtration layer, or the filtration layer is excessively silted up in a short period of time, thereby affecting the water collection volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic structural diagram of a calibration test column device according to the present invention;

[0033] Figure 2 This is a schematic structural diagram of a simulation test column device according to the present invention;

[0034] Figure 3 This is a structural diagram of the simulation test box device of the present invention;

[0035] Figure 4 The total SS removal rate diagram under different filter media and thickness conditions;

[0036] Figure 5 This is a line graph showing the change of infiltration rate over time under 3000NTU influent turbidity.

[0037] In the attached drawings, 1-1 is a rated water supply tank, 1-2 is a rated test column, 1-3 is a rated agitator, 1-4 is a rated submersible pump, 1-5 is a rated water inlet pipe, 1-6 is a rated water inlet, 1-7 is a rated water outlet, and 1-8 is a rated column filter layer;

[0038] 2-1 simulated water supply tank, 2-2 first simulated test column, 2-3 second simulated test column, 2-4 simulated agitator, 2-5 simulated submersible pump, 2-6 simulated water inlet pipe, 2-7 simulated water inlet, 2-8 simulated connecting pipe, 2-9 simulated peristaltic pump, 2-10 simulated water outlet, 2-11 simulated column filter layer;

[0039] 3-1 test chamber water supply tank, 3-2 first simulation test chamber, 3-3 second simulation test chamber, 3-4 test chamber agitator, 3-5 test chamber submersible pump, 3-6 test chamber water inlet pipe, 3-7 test chamber water inlet, 3-8 test chamber top water outlet, 3-9 test chamber connecting pipe, 3-10 test chamber peristaltic pump, 3-11 test chamber water outlet, 3-12 test chamber filter layer. DETAILED DESCRIPTION

[0040] A set of physical test equipment for simulating riverbed infiltration and water extraction includes three test devices: a calibration test column, a simulation test column and a simulation test box. The calibration test column device is used to test the filtering and turbidity removal capabilities of sand and gravel filter media of different particle sizes and thicknesses. Through the calibration test column test, various types and thicknesses of filter media that meet the needs of the project can be preliminarily selected; the simulation test column device is used to combine the different types of filter media preliminarily selected through the calibration test column test according to the preliminarily selected thickness in the simulation test column, and test the overall infiltration and water extraction function (including water quality and water quantity) after the combination. Through the simulation test column device test, the type, thickness and combination order of the filter media can be basically selected; the simulation test box device test is used to install the basically selected various filter media according to the basically selected thickness and combination order in a larger-scale simulation test box. Due to the large cross-sectional size of the simulation test box, the side wall effect of the simulation test column during the test can be eliminated, and the flow rate of the upper river water can be simulated, which is closer to the actual project. Through the simulation test box test, the rationality of the design of the filter layer around the water collection corridor can be effectively verified, and the filter layer design scheme can be finally determined. The following is a description of the calibration test column device (see Figure 1 ), simulation test column device (see Figure 2 ) and simulation test chamber device (see Figure 3 ) experiments are described separately.

[0041] (1) Calibration test column device test

[0042] The calibration test column device includes two calibration test columns 1-2 and a calibration water supply tank 1-1. The calibration test columns 1-2 are provided with calibration water outlets 1-7, which are arranged at intervals. A calibration water inlet 1-6 is provided on the top. The calibration water supply tank 1-1 is provided with a calibration agitator 1-3 and a calibration submersible pump 1-4. The calibration submersible pump 1-4 is connected to the two calibration water inlets 1-6 through a calibration water inlet pipe 1-5. The calibration test columns 1-2 are marked with scales at different heights, and each calibration test column 1-2 has at least two calibration water outlets 1-7.

[0043] The calibration test column 1-2 consists of two test columns. Before the test, they are filled with filter media of different particle sizes for turbidity removal capacity calibration. Calibration outlets 1-7 are set at regular intervals along the height direction to facilitate water sampling from the filter layers 1-8 of the calibration columns with different thicknesses. Rubber hoses are wrapped around the calibration outlets 1-7, and spring clips control the water outlet switch. Figure 1 .

[0044] After the test begins, soil and a calibration mixer 1-3 are added to the calibration water supply tank 1-1 to prepare test water with different turbidities. Water is then pumped through the calibration submersible pump 1-4, and then pumped through the calibration water inlet pipe 1-5 and injected into the calibration test column 1-2 through the calibration water inlet 1-6. After the overflow stabilizes, the timer starts and water samples are collected in sequence. During the test, water samples are taken from the calibration outlet 1-7 at different heights along the calibration test column 1-2 (representing different thicknesses of the calibration column filter layer 1-8) at intervals of 2 minutes, 5 minutes, and 10 minutes (later sampling intervals are all 10 minutes). Sampling is stopped until the turbidity of the outlet water stabilizes, the turbidity test data is recorded, and statistical charts are formed. By analyzing the charts and combining the water turbidity requirements required by the project, various filter media types and thicknesses that meet the project needs are preliminarily selected.

[0045] Taking the emergency water source project (surface water) in the main urban area of Shijiazhuang as an example, when designing a large-scale riverbed infiltration and water collection structure, in order to determine the setting of the filter layer, an infiltration and water collection test was carried out in the design stage. In the test stage of calibration test column 1-2, fine sand (0.35-0.5mm), coarse sand (0.5-2mm), small gravel (2-4mm), medium gravel (4-8mm), and large gravel (8-32mm) were selected as the calibration column filter layer to conduct turbidity removal capacity calibration test. In this test, the two calibration test columns 1-2 are both 1.0m high and 0.1m in diameter. A calibration outlet 1-7 is set every 0.1m in the height direction, which can meet the calibration test of two types of filter materials at the same time. During the test, the thickness of each filter layer was selected into five types: 10cm, 30cm, 50cm, 70cm, and 90cm. The test results show that the turbidity removal capacity (SS removal rate) of various filter materials under different thickness conditions is as follows: Figure 4 shown.

[0046] (2) Simulation test column device test

[0047] The simulation test column device includes two simulation test columns and a simulation water supply tank 2-1, the two simulation test columns are respectively a first simulation test column 2-2 and a second simulation test column 2-3; a simulation water outlet 2-10 is provided at the bottom of the simulation test column, and a simulation water inlet 2-7 is provided at the top; the simulation water supply tank 2-1 is provided with a simulation stirrer 2-4 and a simulation submersible pump 2-5;

[0048] The simulated submersible pump 2-5 is connected to the simulated water inlet 2-7 of the first simulated test column 2-2 via a simulated water inlet pipe 2-6. The simulated water outlet 2-10 at the bottom of the first simulated test column 2-2 is connected to the simulated water inlet 2-7 of the second simulated test column 2-3 via a simulated connecting pipe 2-8. A simulated peristaltic pump 2-9 is installed on the simulated connecting pipe 2-8 between the first simulated test column 2-2 and the second simulated test column 2-3. The simulated test columns are provided with scales.

[0049] The simulation test column device test is used to simulate the filtration effect of the primary filter layer. Considering that the thickness of the filter layer is generally large, in order to reduce the height of the simulation test column, the device is divided into two parts, the first simulation test column 2-2 and the second simulation test column 2-3. The simulated connecting pipe 2-8 and the simulated peristaltic pump 2-9 are used in the middle to connect the two parts, so that the left and right simulation test columns can simulate the actual thickness of the filter layer. Wrap the rubber hose around the simulated water outlet 2-10 at the bottom of the second simulation test column 2-3 on the left, and the spring clip controls the water outlet switch. Before the test begins, the primary filter material is filled in layers according to the primary thickness to form a simulated column filter layer 2-11. Schematic diagram of the test device Figure 2 .

[0050] After the test begins, simulated agitator 2-4 stirs a 1000L water tank to create test water of varying turbidity while maintaining a stable solution concentration. Simulated submersible pump 2-5 pumps water from simulated water supply tank 2-1 through simulated inlet pipe 2-6 and into the first simulated test column 2-2 via simulated water inlet 2-7. The pumping speed of simulated submersible pump 2-5 is adjusted to stabilize the water supply flow rate and flow rate. At simulated outlet 2-10 at the bottom of the second simulated test column 2-3, the turbidity and volume of the outlet water are measured at intervals of 2 minutes, 5 minutes, and 10 minutes (later testing intervals are 10 minutes). Testing is stopped until both turbidity and volume are stable. Turbidity and volume data are recorded and statistically graphed. Analysis of the graphs determines whether the initially selected filter media design meets the project requirements. If not, the filter media particle size and thickness of the simulated column filter layer can be adjusted and the test repeated. Testing the simulated test column apparatus allows for the selection of the filter media type, thickness, and combination sequence.

[0051] When conducting the simulation test column device test for the emergency water source project (surface water) in the main urban area of Shijiazhuang City, based on the test results of the calibration test column device and combined with the distribution of sand and gravel in the project area, the filter media types and thicknesses initially selected from top to bottom are 2.0m thick fine sand (0.35-0.2mm), 0.5m thick (0.5-2mm) coarse sand, 0.5m thick small gravel (2-4mm), 0.5m thick medium gravel (4-8mm), and 0.5m large gravel (8-32mm). The effective height of the first and second simulation test columns in this test was 2.0m. The first simulation test column 2-2 was filled with 2.0m thick fine sand (0.35-0.2mm); the second simulation test column 2-3 was filled with 0.5m thick coarse sand (0.5-2mm), 0.5m thick small gravel (2-4mm), 0.5m thick medium gravel (4-8mm), and 0.5m thick large gravel (8-32mm) from top to bottom. The test was then carried out. The turbidity value of the test water was less than 5.0NTU, which met the water quality requirements. However, the comprehensive permeability coefficient of the entire filter layer after combination was only 0.8×10 -3 cm / s, which did not meet the water collection requirements. The reason was that the thickness of the fine material was too large. The filter material combination was adjusted and the simulation test column test was repeated, and relatively ideal test results were obtained. The test effluent turbidity value was less than 5.0 NTU, and the comprehensive permeability coefficient of the filter layer was 0.73×10 -2 cm / s, which can meet the water collection requirements. The adjusted filter material combination is: 1.2m thick coarse sand (0.5-2mm), 0.5m thick small gravel (2-4mm), 0.5m thick medium gravel (4-8mm), and 1.5m thick large gravel (8-32mm).

[0052] (3) Simulation test chamber device test

[0053] The size of the simulation test box is larger than that of the simulation test column.

[0054] The simulation test chamber device includes two simulation test chambers and a test chamber water supply tank 3-1. The two simulation test chambers are respectively a first simulation test chamber 3-2 and a second simulation test chamber 3-3. The first simulation test chamber 3-2 is provided with a first test chamber water outlet 3-8 and a test chamber water inlet 3-7. The top of the first simulation test chamber 3-2 is provided with a test chamber water outlet 3-8 opposite to the test chamber water inlet 3-7, and the test chamber water outlet 3-8 is lower in elevation than the test chamber water inlet 3-7. The test chamber water inlet 3-7 of the second simulation test chamber is provided with at least two water inlet branches in parallel. The test chamber water supply tank 3-1 is provided with a test chamber agitator 3-4 and a test chamber submersible pump 3-5.

[0055] The test box submersible pump 3-5 is connected to the first test box water inlet 3-7 of the first simulation test box 3-2 through a simulated water inlet pipe, and the first test box water outlet 3-7 is connected to the test box water inlet of the second simulation test box 3-3 through a test box connecting pipe 3-9. A test box peristaltic pump 3-10 is provided on the test box connecting pipe 3-9 between the first simulation test box 3-2 and the second simulation test box 3-3. Scales are provided on the first simulation test box 3-2 and the second simulation test box 3-3 for marking the thickness of each layer of filter material in the first simulation test box 3-2 and the second simulation test box 3-3.

[0056] The simulation test box device test is used to simulate the filtration effect of the basically selected inverse filter layer under the real infiltration boundary conditions. Considering that the actual set inverse filter layer thickness is generally large, in order to reduce the height of the test box, the large test box is divided into two parts. The test boxes on the left and right sides are the first simulation test box 3-2 and the second simulation test box 3-3. The test box peristaltic pump 3-10 and the test box connecting pipe 3-9 are used in the middle of the two simulation test boxes to connect the first simulation test box 3-2 and the second simulation test box 3-3 at the head and tail, and enter the second simulation test box 3-3 through the first test box outlet 3-8. The surface of the first simulation test box 3-2 simulates the riverbed water flow, and the water flow rate can be changed by adjusting the opening of the test box water inlet 3-7. Before the test starts, the pre-selected filter material is filled in layers according to the pre-selected thickness. Schematic diagram of the test box test device Figure 3 .

[0057] After the test begins, the test chamber agitator 3-4 stirs the 2000L water tank to create test water of varying turbidity while maintaining a stable solution concentration. The test chamber submersible pump 3-5 pumps water from the test chamber water supply tank 3-1 through the test chamber water inlet 3-7 into the first simulation test chamber 3-2 via the test chamber water inlet pipe 3-6. The pumping speed of the test chamber submersible pump 3-5 is adjusted to stabilize the water supply flow rate and flow rate. The turbidity and water volume of the outlet water are tested at the second test chamber outlet 3-11 at the bottom of the second simulation test chamber 3-3 at intervals of 2 minutes, 5 minutes, and 10 minutes (later testing intervals are all 10 minutes). The test is terminated until both the turbidity and water volume are stable. The turbidity and water volume data are recorded and statistically graphed. By analyzing the graphs, it is verified whether the filter material design meets the project requirements.

[0058] During the simulation test chamber test of the Shijiazhuang City Main Urban Area Emergency Water Source Project (surface water), based on the results of the simulation test column test, the filter media combinations selected, from top to bottom, were: 1.2m thick coarse sand (0.5-2mm), 0.5m thick small gravel (2-4mm), 0.5m thick medium gravel (4-8mm), and 1.5m thick large gravel (8-32mm). The first and second simulation test chambers 3-2 and 3-3 used in this experiment were both 2.0m high, 2m long, and 1m wide. The filter media were loaded into the first and second simulation test chambers 3-2 and 3-3 in this order. The first simulation test chamber contained a filter media composition of 1.2m thick coarse sand (0.5-2mm) and 0.5m thick small gravel (2-4mm) from top to bottom, with the free water surface above the coarse sand to simulate river flow velocity. The second simulation test chamber contained a filter media composition of 0.5m thick medium gravel (4-8mm) and 1.5m thick large gravel (8-32mm) from top to bottom. The test yielded an effluent turbidity value of less than 5.0 NTU, meeting effluent quality requirements. However, with higher influent turbidity (3000 NTU), the permeability coefficient of filter layer 3-12 in the test chamber declined rapidly, reaching essentially zero after 100 hours of operation, indicating that filter layer 3-12 was completely clogged with sediment from the high-turbidity water. The reason was analyzed to be that the sediment in the high turbidity water was directly deposited on the surface of the filter layer 3-12 of the test box, causing serious clogging. Subsequently, a layer of 0.5m thick porous volcanic rock gravel (40-60mm) was added on the top of the filter layer 3-12 of the test box to absorb the sediment in the water, and the thickness of large gravel (8-32mm) was reduced to 1.0m. After the adjustment, the filter material combination in the first simulation test box was 0.5m thick porous volcanic rock gravel (40-60mm) and 1.2m thick 0.5-2mm coarse sand from top to bottom. Above the porous volcanic rock gravel was the free water surface, simulating the flow velocity of the river channel; the filter material combination in the second simulation test box was 0.5m thick small gravel (2-4mm), 0.5m thick medium gravel (4-8mm), and 1.0m large gravel (8-32mm) from top to bottom. Then the simulated water tank test was carried out again. The turbidity value of the test water was less than 5.0 NTU, which met the water quality requirements. The permeability coefficient of the test tank filter layer 3-12 reached stability after a period of decay. After the siltation of the test tank filter layer 3-12 stabilized, the permeability coefficient was 20% to 25% of the pre-siltation value. Figure 5 .

[0059] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. A test method for simulating riverbed infiltration and water collection, characterized in that: The following steps are involved: S1. Use the calibration test column device to test the filtration and turbidity removal capabilities of filter media of different particle sizes and thicknesses, and preliminarily select the types and thicknesses of filter media that meet the project needs through the test; S2. Combine various filter materials that meet the project requirements after preliminary selection through testing and load them into a simulated test column device. Test the overall infiltration and water extraction function of the combined materials to select the type, thickness, and combination order of the filter materials and form a filter material design plan. S3. Install the selected various filter materials in the simulation test box according to the selected thickness and combination order, simulate the upper river flow rate, conduct test analysis, and verify whether the filter material design scheme meets the project needs.

2. The test method for simulating riverbed infiltration and water collection according to claim 1, characterized in that: The specific steps of S1 are as follows: first, the filter material to be tested for turbidity removal capacity is loaded into the calibration test column device, and two calibration test columns are loaded with different types of filter materials, and the tests are carried out simultaneously; by adding soil and water into the water supply tank and stirring with a calibration stirrer to prepare test water with different turbidities, the water is then pumped into the calibration test column by a calibration submersible pump, and after the overflow stabilizes, the timing is started and water samples are taken in sequence. Different heights of the calibration test column represent different thicknesses of the filter material. During the test, water samples are taken at intervals of 2 minutes, 5 minutes and 10 minutes along different heights of the calibration test column, and then the sampling interval is always 10 minutes. Sampling is stopped until the turbidity of the outlet water stabilizes, the turbidity detection data is recorded, and a statistical chart is formed; by analyzing the calibration test charts of various filter materials, the turbidity removal capacity of different filter materials under different thickness conditions is obtained, and combined with the water intake turbidity requirements required by the project, various filter material types and thicknesses that meet the project needs are preliminarily selected.

3. The test method for simulating riverbed infiltration and water collection according to claim 1, characterized in that: The specific steps of S2 are as follows: first, the various preliminarily selected filter materials are combined according to different thicknesses and sequentially loaded into the simulation test column device; after the test starts, the simulated stirrer stirs the simulated water supply tank to form test water of different turbidities and keeps the solution concentration stable; the simulated submersible pump is connected to the simulation test column for water supply, the pump speed of the simulated submersible pump is adjusted to stabilize the water supply flow rate and flow rate, and the flow rate of the simulated peristaltic pump is adjusted to be the same as that of the simulated submersible pump; the turbidity and water volume of the outlet water are tested at the simulated outlet at the bottom of the second simulation test column every 2 minutes, 5 minutes and 10 minutes, and then the sampling interval is always 10 minutes until the turbidity and water volume of the outlet water are stable, and the test is stopped, the turbidity test data and water volume data are recorded, and statistical charts are formed; by analyzing the charts, it is judged whether the preliminarily selected filter material design scheme meets the project needs. If it does not meet the requirements, the filter material particle size and thickness are adjusted and the test is repeated; the type, thickness and combination order of the filter material are selected through the simulation test column test; The overall infiltration water intake function described in S2 includes the water quality and water quantity of the intake water.

4. The test method for simulating riverbed infiltration and water collection according to claim 1, characterized in that: The specific steps of S3 are: First, the selected various filter materials are combined according to the planned thickness and loaded into the simulation test chamber device in sequence; after the test starts, the test chamber agitator stirs the test chamber water supply tank to form test water with different turbidities and maintain a stable solution concentration; the test chamber submersible pump water supply is connected to the simulation test chamber, and the pump speed of the test chamber submersible pump is adjusted to stabilize the water supply flow rate and flow rate. At the same time, the opening of the water inlet of the first simulation test chamber is adjusted so that the water flow on the top surface of the filter material in the test chamber reaches the design flow rate, and the pump speed of the peristaltic pump of the test chamber is adjusted so that the water levels in the two test chambers can be kept stable respectively. The turbidity and water volume of the outlet water are tested at the water outlet at the bottom of the second simulation test chamber every 2 minutes, 5 minutes and 10 minutes, and then the sampling interval is always 10 minutes. The test is stopped until the turbidity and water volume of the outlet water are stable, and the turbidity test data and water volume data are recorded and statistical charts are formed; by analyzing the charts, it is verified whether the filter material design scheme meets the project needs.

5. The test device for simulating riverbed infiltration and water collection used in the test method for simulating riverbed infiltration and water collection according to any one of claims 1 to 4, characterized in that: Includes calibration test column apparatus; The calibration test column device includes two calibration test columns and a calibration water supply tank. The calibration test columns are provided with calibration water outlets, which are arranged at intervals, and a calibration water inlet is provided on the top. The calibration water supply tank is provided with a calibration agitator and a calibration submersible pump, and the calibration submersible pump is connected to the two calibration water inlets respectively through a calibration water inlet pipe.

6. The test device for simulating riverbed infiltration and water collection according to claim 5, characterized in that: The calibration test column is marked with scales at different heights, and each calibration test column has at least two calibration water outlets.

7. The test device for simulating riverbed infiltration and water collection according to claim 6, characterized in that: According to the order of use, after using the calibration test column device, the simulation test column device is also used; The simulation test column device includes two simulation test columns and a simulation water supply tank. The bottom of the simulation test column is provided with a simulation water outlet, and the top is provided with a simulation water inlet. The simulation water supply tank is provided with a simulation stirrer and a simulation submersible pump. The two simulation test columns are respectively a first simulation test column and a second simulation test column; The simulated submersible pump is connected to the simulated water inlet of the first simulated test column through a pipeline, and the simulated water outlet at the bottom of the first simulated test column is connected to the simulated water inlet of the second simulated test column through a simulated connecting pipeline.

8. The test device for simulating riverbed infiltration and water collection according to claim 7, characterized in that: A simulated peristaltic pump is provided on the simulated connecting pipe between the first simulated test column and the second simulated test column. Scales are marked at different heights on the upper edge of the simulated test column to mark the thickness of each layer of filter material in the first simulated test column and the second simulated test column.

9. The test device for simulating riverbed infiltration and water collection according to claim 8, characterized in that: According to the order of use, after using the simulation test column device, the simulation test box device is also used; The simulation test chamber device includes two simulation test chambers and a test chamber water supply tank. The two simulation test chambers are respectively a first simulation test chamber and a second simulation test chamber. The first simulation test chamber is provided with a test chamber water outlet and a test chamber water inlet. The test chamber water supply tank is provided with a test chamber agitator and a test chamber submersible pump. The test box submersible pump is connected to the test box water inlet of the first simulation test box through the test box water inlet pipe, and the test box water outlet of the first simulation test box is connected to the test box water inlet of the second simulation test box through the test box connecting pipe; The size of the simulation test box is larger than that of the simulation test column.

10. The test device for simulating riverbed infiltration and water collection according to claim 9, characterized in that: A test box peristaltic pump is provided on the test box connecting pipe between the first simulation test box and the second simulation test box. Scales are marked at different heights on the upper edges of the first simulation test box and the second simulation test box for marking the thickness of each layer of filter material in the first simulation test box and the second simulation test box. A water outlet is provided on the top of the first simulation test box opposite to the water inlet of the test box, and the elevation of the water outlet is lower than the water inlet of the test box; The water inlet of the second simulation test chamber is provided with no less than two water inlet branches in parallel.

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