Device and method for dynamic leaching experiment on formation and evolution of groundwater in unsaturated zone

Abstract

The present invention belongs to the field of hydrogeology and specifically discloses an apparatus and method for conducting dynamic leaching experiments to study the formation and evolution of groundwater in an unsaturated zone. The apparatus includes a water supply tank, a liquid outlet valve, a liquid outlet pipe, a spray, an organic glass experimental column, a solid sample sampling port, a filter layer, a liquid sample sampling valve, an organic glass bottom column, a circulating water tank, a peristaltic pump, and an experimental bench. The method conducts circulating leaching experiments and conventional leaching experiments on solid samples at different locations, dynamically simulating the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock formations during lateral and vertical flow after infiltration into the unsaturated zone, thereby studying the formation mechanism of groundwater in the unsaturated zone. The present invention can study the lateral runoff and vertical infiltration of groundwater in the unsaturated zone by conducting circulating leaching experiments and conventional leaching experiments, respectively, to more comprehensively understand the formation and evolution of groundwater in the unsaturated zone.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogeology, and in particular relates to a device and method for dynamic leaching experiments suitable for studying the formation and evolution laws of groundwater in unsaturated zones. Background Art

[0002] The rock layers below the surface, above the water table, are called the unsaturated zone. This zone serves as a hub for the exchange of moisture and energy between atmospheric and surface water and saturated groundwater. Therefore, studying the formation and evolution of groundwater in the unsaturated zone is a crucial component of research into the transformation and formation of different water bodies. However, research on water-rock interactions during the infiltration of atmospheric or surface water through the unsaturated zone to recharge groundwater is relatively limited, and existing studies have mostly focused on static simulations. In reality, completely static water-rock interactions do not exist.

[0003] In order to solve the above problems, it is urgent to invent a device and technology for dynamic leaching experiments suitable for studying the formation and evolution laws of groundwater in the unsaturated zone. Summary of the Invention

[0004] The purpose of the present invention is to provide a device and method for dynamic leaching experiments suitable for studying the formation and evolution laws of unsaturated zone groundwater. By conducting cyclic leaching experiments and ordinary leaching experiments, the lateral runoff and vertical infiltration of unsaturated zone groundwater can be studied respectively, so as to more comprehensively understand the formation and evolution laws of unsaturated zone groundwater.

[0005] The technical solution for achieving the purpose of the present invention is as follows: a device for dynamic leaching experiment on the formation and evolution law of groundwater in an unsaturated zone, the device comprising a water supply tank, a liquid outlet valve, a liquid outlet pipe, a spray, a plexiglass experimental column, a solid sample sampling port, a filter layer, a liquid sample sampling valve, a plexiglass bottom column and an experimental bench, the bottom of the water supply tank is installed on the left table of the experimental bench, the right side of the water supply tank is connected to one end of the liquid outlet valve, the other end of the liquid outlet valve is connected to one end of the liquid outlet pipe, and the other end of the liquid outlet pipe is connected to the inlet of the spray; the spray nozzle cover is on the top of the plexiglass experimental column, and a solid sample sampling port is opened on the side wall of the plexiglass experimental column; a filter layer is laid inside the bottom of the plexiglass experimental column, an plexiglass bottom column is provided outside the bottom of the plexiglass experimental column, a liquid sample sampling port is opened on the side wall of the plexiglass bottom column, and a liquid sample sampling port is installed on the liquid sample sampling port.

[0006] A water tank top cover is provided on the top of the water supply tank.

[0007] A water tank cleaning valve is provided at the bottom of the water supply tank.

[0008] A circulating water tank is provided in the frame on the right side of the experimental bench and below the organic glass bottom column. The circulating water tank is connected to the organic glass experimental column through a connecting hose.

[0009] A circulation valve is provided at the bottom of the organic glass experimental column. The circulation valve is connected to one end of a connecting hose, and the other end of the connecting hose is communicated with the circulation valve through a thread.

[0010] A circulating water tank top cover is provided on the top of the circulating water tank, and one end of the connecting hose passes through the circulating water tank top cover and is inserted into the circulating water tank.

[0011] An automatic float valve is installed inside the circulating water tank.

[0012] A peristaltic pump is provided between the circulating water tank and the water supply tank.

[0013] The peristaltic pump is installed in the frame at the bottom left side of the experimental bench.

[0014] The inlet of the peristaltic pump is connected to the circulating water tank through a circulating pipe.

[0015] The peristaltic pump is connected to the water supply tank through a liquid return pipe.

[0016] A peristaltic pump control switch is provided on the left middle frame of the experimental bench. One end of the peristaltic pump control switch is connected to the control end of the peristaltic pump through a cable, and the other end of the peristaltic pump control switch is connected to the power supply through a cable.

[0017] The filter layers are composed of a nylon layer, a quartz sand layer and a nylon layer from top to bottom.

[0018] The side wall of the organic glass experimental column is evenly spaced from top to bottom with a plurality of solid sample sampling ports.

[0019] The bottom of the organic glass experimental column and the top of the organic glass bottom column are connected via a connecting flange.

[0020] A method for dynamic leaching experiment on the formation and evolution of groundwater in an unsaturated zone, the method specifically comprising the following steps:

[0021] Step 1: Select the sampling location in the study area and collect solid samples at the sampling point;

[0022] Step 2: measuring and analyzing the solid samples collected at different locations in the above step 1;

[0023] Step 3: Conducting a cyclic leaching experiment on the solid samples collected and analyzed at different locations in Step 2 above, dynamically simulating the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock formations during lateral runoff after infiltration into the unsaturated zone;

[0024] Step 4: Perform a common leaching experiment on the solid samples collected and analyzed at different locations in step 2 using the above-mentioned dynamic leaching experimental device to dynamically simulate the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock layer during the vertical infiltration process after infiltration of the unsaturated zone, and study the formation mechanism of groundwater in the unsaturated zone.

[0025] The step 3 is as follows:

[0026] Step 3.1. Place the solid sample into the organic glass experimental column of the dynamic leaching experimental device and fill the water supply tank with deionized water;

[0027] Step 3.2: The water supply tank supplies deionized water to the organic glass experimental column;

[0028] Step 3.3: Start the peristaltic pump, and the deionized water flowing out of the organic glass experimental column is circulated and leached in the dynamic leaching experimental device in turn;

[0029] Step 3.4: regularly open the liquid sample sampling valve to perform liquid sample sampling and testing, thereby dynamically simulating the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock layer during the lateral runoff process after the infiltration of atmospheric water or surface water into the unsaturated zone.

[0030] The step 3.1 is specifically as follows: a solid sample is placed in a plexiglass experimental column of a dynamic leaching experimental device, and deionized water is placed in a water supply tank of the dynamic leaching experimental device to carry out a circulating leaching experiment.

[0031] The step 3.2 is specifically as follows: open the liquid outlet valve, close the liquid sample sampling valve, open the circulation valve, and the deionized water in the water supply tank flows through the liquid outlet pipe and sprays into the organic glass experimental column.

[0032] The specific steps of step 3.3 are as follows: turn on the peristaltic pump control switch, start the peristaltic pump, and filter the deionized water in the organic glass experimental column through the filter layer under the action of the peristaltic pump. After filtration, the deionized water flows through the organic glass bottom column, the connecting hose, the circulating water tank, the circulating pipe, the peristaltic pump, the return pipe and enters the water supply tank, and then repeat steps 3.2 to 3.3 to realize the circulating leaching.

[0033] The step 3.4 is specifically as follows: at regular intervals, the peristaltic pump stops working, the liquid sample sampling valve is opened, the reacted liquid sample is taken out, and the collected reacted liquid sample is sealed and stored in a polyethylene sampling bottle.

[0034] The step 4 is specifically as follows:

[0035] Step 4.1, cleaning the dynamic leaching experimental device after the reaction in step 3;

[0036] Step 4.2: Place the solid sample into the organic glass experimental column of the dynamic leaching experimental device, fill the water supply tank with deionized water, and conduct a normal leaching experiment;

[0037] Step 4.3: The water supply tank supplies deionized water to the organic glass experimental column; the deionized water flowing out of the organic glass experimental column is leached normally in the dynamic leaching experimental device;

[0038] Step 4.4: Open the liquid sample sampling valve regularly to conduct liquid sample sampling and testing, thereby dynamically simulating the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock formations during the vertical infiltration process after infiltration into the unsaturated zone, and studying the formation mechanism of groundwater in the unsaturated zone.

[0039] The step 4.3 is as follows: open the liquid outlet valve, open the liquid sample sampling valve, and close the circulation valve; the deionized water in the water supply tank enters the organic glass experimental column through the liquid outlet pipe and sprays, and flows into the organic glass bottom column after being filtered through the filter layer.

[0040] The step 4.4 is specifically as follows: at regular intervals, the liquid sample sampling valve is opened to take out the post-reaction liquid sample, and the collected post-reaction liquid sample is sealed and stored in a polyethylene sampling bottle.

[0041] The beneficial technical effects of the present invention are as follows: the present invention can dynamically simulate the lateral runoff of groundwater in the unsaturated zone through the cyclic leaching experiment module, and can dynamically simulate the vertical infiltration of groundwater through the unsaturated zone through the conventional leaching experiment module, thereby comprehensively and systematically revealing the formation and evolution of groundwater in the unsaturated zone in a more realistic and comprehensive manner. The present invention can perform both cyclic leaching experiments and conventional leaching experiments by turning the peristaltic pump 18 on and off, achieving the effect of multiple uses of a single device. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic structural diagram of a device for dynamic leaching experiments provided by the present invention.

[0043] In the figure: 1-water supply tank top cover, 2-water supply tank, 3-liquid outlet valve, 4-liquid outlet pipe, 5-spray, 6-plexiglass experimental column, 7-solid sample sampling port, 8-filter layer, 9-connecting flange, 10-liquid sample sampling valve, 11-plexiglass bottom column, 12-circulation valve, 13-connecting hose, 14-circulating water tank top cover, 15-automatic float valve, 16-circulation pipe, 17-circulating water tank, 18-peristaltic pump, 19-return liquid pipe, 20-experimental bench, 21-peristaltic pump control switch, 22-water supply tank cleaning valve. DETAILED DESCRIPTION

[0044] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0045] like Figure 1 As shown, the present invention provides a device for a dynamic leaching experiment, which includes a water supply tank 2, an organic glass experimental column 6, an organic glass bottom column 11, a circulating water tank 17, a peristaltic pump 18, a test bench 20, and a water supply tank top cover 1, a liquid outlet valve 3, a liquid outlet pipe 4, a spray 5, a solid sample sampling port 7, a filter layer 8, a connecting flange 9, a liquid sample sampling valve 10, a circulating valve 12, a connecting hose 13, a circulating water tank top cover 14, an automatic float valve 15, a circulating pipe 16, a return pipe 19, a peristaltic pump control switch 21, and a water supply tank cleaning valve 22.

[0046] A water tank top cover 1 is provided on the top of the water supply tank 2, and the two are fixedly connected by bolts; the bottom of the water supply tank 2 is fixed to the left table of the experimental bench 20 by bolts; a water tank cleaning valve 21 is provided at the bottom of the water supply tank 2, and one end of the water tank cleaning valve 21 is fixedly connected to the bottom cleaning port of the water supply tank 2 by a thread; the left return liquid port of the water supply tank 2 is connected to one end of the return liquid pipe 19, and the two are fixedly connected by a clamping ring; the right liquid outlet of the water supply tank 2 is fixedly connected to one end of the liquid outlet valve 3 by bolts, and the other end of the liquid outlet valve 3 is fixedly connected to one end of the liquid outlet pipe 4 by a thread, and the other end of the liquid outlet pipe 4 is connected to the inlet of the spray 5, and the two are fixedly connected by bolts.

[0047] The nozzle cover of the spray 5 is on the top of the organic glass experimental column 6; the side wall of the organic glass experimental column 6 is evenly spaced from top to bottom with three solid sample sampling ports 7, and a filter layer 8 is laid inside the bottom of the organic glass experimental column 6. The filter layer 8 has three layers in total, and the filter layer 8 is a nylon layer, a quartz sand layer, and a nylon layer from top to bottom; the bottom of the organic glass experimental column 6 is fixedly connected to the top of the organic glass bottom column 11 located outside its bottom through a connecting flange 9 and bolts.

[0048] A liquid sample sampling port is opened on the side wall of the organic glass bottom column 11, and a liquid sample sampling valve 10 is installed on the liquid sample sampling port, and the two are fixedly connected by threads. A circulation valve 12 is installed at the bottom of the organic glass bottom column 11 and the two are fixedly connected by threads. The bottom of the organic glass bottom column 11 is fixed on the right side table of the experimental bench 20.

[0049] 18 is connected to the water supply tank 20 via a pipe 16. The water supply tank 20 is connected to the water supply tank 20 via a pipe 17. The water supply tank 20 is connected to the water supply tank 20 via a pipe 16. The water supply tank 20 is connected to the water supply tank 20 via a pipe 17. The water supply tank 20 is connected to the water supply tank 20 via a pipe 16. The water supply tank 20 is connected to the water supply tank 20 via a pipe 16. The water supply tank 20 is connected to the water supply tank 20 via a pipe 16. The water supply tank 20 is connected to the water supply tank 20 via a pipe 16. The water supply tank 20 is connected to the water supply tank 20 via a pipe 16.

[0050] The working principle of the device for dynamic leaching experiment provided by the present invention is as follows:

[0051] According to the needs of different scenarios, select leachate that can meet the experimental requirements and solid sediment samples that are suitable for the experimental requirements.

[0052] Close the water tank cleaning valve 22, load the prepared leachate into the water tank 2, and close the water tank cover 1. Place the nylon cloth and quartz sand of the filter layer 8 into the organic glass test column 6 as required. Seal the three solid sample ports 7 with rubber stoppers. Then, layer the prepared solid sediment samples into the organic glass test column 6, and cover the top of the organic glass test column 6 with the spray nozzle 5.

[0053] At this time, two types of leaching experiments can be carried out, one is the circulating leaching experiment, and the other is the ordinary leaching experiment, which are introduced in detail below.

[0054] Circulation leaching experiment: Start the circulation leaching experiment, turn on the peristaltic pump control switch 21, open the liquid outlet valve 3, close the liquid sample sampling valve 10, open the circulation valve 12, and perform circulation leaching according to the experimental design. Open the liquid sample sampling valve 10 regularly according to the experimental requirements for sampling. At the end of the experiment, take samples from the solid sample sampling port 7 for subsequent research and analysis.

[0055] Ordinary leaching experiment: Start the ordinary leaching experiment, open the liquid outlet valve 3, open the liquid sample sampling valve 10, close the circulation valve 12, and take liquid samples regularly according to the experimental requirements. At the end of the experiment, take samples from the solid sample sampling port 7 for subsequent research and analysis.

[0056] After the experiment is finished, clean the entire experimental device and use it again in the next experiment.

[0057] The present invention provides a method for dynamic leaching experiment of formation and evolution law of groundwater in unsaturated zone, which specifically comprises the following steps:

[0058] Step 1: Select the sampling location in the study area and collect solid samples at the sampling point

[0059] Previous geological, hydrogeological, and satellite image data of the study area were collected, and field surveys were conducted based on the collected data. Representative upstream, midstream, and downstream valleys in the study area were selected as sampling locations, and sediments from these three sampling locations were taken as solid samples for the dynamic leaching experiment. After collecting the solid samples, the three sediments were air-dried, cleaned, and bagged under the same natural conditions for storage.

[0060] Step 2: Measure the solid samples at different locations collected in step 1 above and perform X-ray diffraction analysis and scanning electron microscopy analysis.

[0061] X-ray diffraction analysis was performed on the sediment solid samples collected in step 1 above from different locations in the upstream, midstream, and downstream valleys of the study area to measure the mineral composition and content of the sediment solid samples at different locations. Scanning electron microscopy was also performed to analyze the microstructure of the sediment solid samples at different locations. Step 3: A cyclic leaching experiment was conducted on the solid samples collected and analyzed at different locations in step 2 above using the dynamic leaching experimental device described above to dynamically simulate the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock formations during lateral runoff after infiltration into the unsaturated zone.

[0062] The solid sediment samples collected and analyzed in step 2 above from the upper, middle and lower reaches of the valley were subjected to a cyclic leaching experiment. Deionized water was used as the liquid sample, and the experimental device was Figure 1 The dynamic leaching experimental device shown has a reaction time of 14 days, and liquid samples are taken once every 24 hours. The experiment is carried out at normal temperature and pressure. Step 3 specifically includes:

[0063] Step 3.1: Place a solid sample into the organic glass experimental column 6 of the dynamic leaching experimental device, and fill the water supply tank 2 with deionized water to carry out a circulating leaching experiment. The specific steps of step 3.1 are as follows:

[0064] Prepare 3 sets Figure 1 As shown in the dynamic leaching experimental device, solid sediment samples from the upstream, midstream and downstream of the valley are respectively loaded into the organic glass experimental columns 6 of the three sets of dynamic leaching experimental devices, and deionized water is respectively loaded into the water supply tanks 2 of the three sets of dynamic leaching experimental devices to carry out a circulating leaching experiment.

[0065] Step 3.2: The water supply tank 2 supplies deionized water to the organic glass experimental column 6. The specific steps of step 3.2 are as follows:

[0066] Open the liquid outlet valve 3, close the liquid sample sampling valve 10, open the circulation valve 12, and the deionized water in the water supply tank 2 enters the organic glass experimental column 6 through the liquid outlet pipe 4 and the spray 5;

[0067] Step 3.3: Start the peristaltic pump 18, and the deionized water flowing out of the organic glass experimental column 6 is circulated and leached in the dynamic leaching experimental device in turn; the specific steps of step 3.3 are as follows:

[0068] Turn on the peristaltic pump control switch 21, the peristaltic pump 18 starts, and the deionized water in the organic glass experimental column 6 is filtered through the filter layer 8 under the action of the peristaltic pump 18. After filtration, the deionized water flows through the organic glass bottom column 11, the connecting hose 13, the circulating water tank 17, the circulating pipe 16, the peristaltic pump 18, the return liquid pipe 19 and enters the water supply tank 2, and then continues to repeat steps 3.2 to 3.3 to realize circular leaching.

[0069] Function of automatic float valve 15: During the cyclic leaching test, as peristaltic pump 18 is turned on, the leachate in circulating water tank 17 gradually decreases, and the water level gradually drops until automatic float valve 15 floats to the bottom of circulating water tank 17, at which point peristaltic pump 18 automatically shuts off. As the leachate in circulating water tank 17 gradually increases, automatic float valve 15 gradually rises, and peristaltic pump 18 reopens. This cycle repeats, automatically performing the cyclic leaching test.

[0070] Step 3.4: Timely open the liquid sample sampling valve 10 to perform liquid sample sampling and testing, thereby dynamically simulating the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock formation during lateral runoff after infiltration into the unsaturated zone. The specific steps of step 3.4 are as follows:

[0071] A post-reaction liquid sample was collected every 24 hours. The specific steps were as follows: Every 24 hours, peristaltic pump control switch 21 was turned off, peristaltic pump 18 stopped operating, and liquid sample valve 10 was opened to collect a post-reaction liquid sample, i.e., a deionized water sample. This was repeated for a total of 14 days. The post-reaction liquid samples collected daily were sealed and stored in polyethylene sampling bottles, and their hydrochemical composition was tested. This dynamically simulated the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock formation during lateral runoff after infiltration into the unsaturated zone.

[0072] When testing the water chemical composition of liquid samples, the ICS-1100 ion chromatograph was used to determine the K + 、Na + , Ca 2+ Mg 2+ , using 883Basic IC plus ion chromatograph to determine Cl in liquid samples - 、SO42- 、F - 、NO3 - , using AT-510 automatic titrator to determine CO3 in liquid samples 2- 、HCO3 - .

[0073] After 14 days, the experiment is finished, the peristaltic pump control switch 21 is turned off, the peristaltic pump 18 stops working, and the solid sample is taken out from the solid sample sampling port 7 for subsequent research and analysis.

[0074] Subsequent analysis of the solid samples included using a Panalytical X'Pert PRO X-ray diffractometer to measure the composition and relative content of the minerals contained in the solid samples, primarily including quartz, feldspar, calcite, gypsum, and other minerals. A Nova Nano SEM450 scanning electron microscope was used to observe the microscopic morphology of the solid samples.

[0075] Step 4: Clean the dynamic leaching experimental device after the reaction in step 3, and use the above-mentioned dynamic leaching experimental device to conduct a common leaching experiment on the solid samples at different locations collected and analyzed in step 2. Dynamically simulate the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock layer during the vertical infiltration process after infiltration of the unsaturated zone to study the formation mechanism of groundwater in the unsaturated zone.

[0076] The solid sediment samples collected and analyzed in step 2 were used for the general leaching experiment. The liquid samples were also deionized water, and the experimental device was Figure 1 The dynamic leaching experimental device shown has a reaction time of 14 days, and liquid samples are taken once every 24 hours. The experiment is carried out at normal temperature and pressure. Step 4 specifically includes:

[0077] Step 4.1: Clean the three sets of samples after the reaction in step 3. Figure 1 The specific steps of step 4.1 are as follows:

[0078] Open the water supply tank cleaning valve 22 of the dynamic leaching experimental device, inject cleaning liquid into the water supply tank 2, open the liquid outlet valve 3, liquid sample sampling valve 10, and circulation valve 12, turn on the peristaltic pump control switch 21, start the peristaltic pump 8, and use the cleaning liquid to clean the water supply tank 2, liquid outlet valve 3, liquid outlet pipe 4, spray 5, solid sample sampling port 7, filter layer 8, connecting flange 9, liquid sample sampling valve 10, organic glass bottom column 11, circulation valve 12, connecting hose 13, circulating water tank 17, circulation pipe 16, peristaltic pump 18, and return liquid pipe 19 in turn to complete the cleaning of the dynamic leaching experimental device.

[0079] After the experiment, the dynamic leaching experimental device was cleaned with deionized water.

[0080] Step 4.2: Place the solid sample into the organic glass experimental column 6 of the dynamic leaching experimental device, fill the water supply tank 2 with deionized water, and conduct a normal leaching experiment; the specific steps of step 4.2 are as follows:

[0081] Solid sediment samples from the upper, middle and lower reaches of the valley were placed in the organic glass experimental columns 6 of the three sets of dynamic leaching devices respectively, and deionized water was placed in the water supply tank 2 to carry out ordinary leaching experiments.

[0082] Step 4.3: The water supply tank 2 supplies deionized water to the organic glass experimental column 6; the deionized water flowing out of the organic glass experimental column 6 is leached normally in the dynamic leaching experimental device; the specific steps of step 4.3 are as follows:

[0083] Open the liquid outlet valve 3, open the liquid sample sampling valve 10, and close the circulation valve 12; the deionized water in the water supply tank 2 enters the organic glass experimental column 6 through the liquid outlet pipe 4 and the spray 5, and flows into the organic glass bottom column 11 after being filtered through the filter layer 8.

[0084] Step 4.4: Timely open the liquid sample sampling valve 10 to perform liquid sample sampling and testing, thereby dynamically simulating the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock formation during the vertical infiltration process after infiltration into the unsaturated zone, and studying the formation mechanism of unsaturated zone groundwater. The specific steps of step 4.4 are as follows:

[0085] A sample of the post-reaction liquid, specifically a deionized water sample, was collected every 24 hours for 14 days. The samples were sealed and stored in polyethylene sampling bottles, and their hydrochemical composition was analyzed. This allowed for a dynamic simulation of the water-rock interaction between atmospheric or surface water and the unsaturated zone during vertical infiltration, allowing for the study of the formation mechanism of groundwater in the unsaturated zone.

[0086] When testing its water chemical composition, the ICS-1100 ion chromatograph was used to determine the K + 、Na + , Ca 2+ Mg 2+ , using 883Basic IC plus ion chromatograph to determine Cl in liquid samples - 、SO4 2- 、F - 、NO3 - , using AT-510 automatic titrator to determine CO3 in liquid samples 2- 、HCO3 - .

[0087] Step 5: After the experiment, clean the three sets of dynamic leaching experimental devices.

[0088] After 14 days, the experiment was completed and the solid sample was taken out from the solid sample sampling port 7. Then, the three sets of dynamic leaching experimental devices were cleaned using the method in step 4.1 above.

[0089] The solid sample removed from solid sample sampling port 7 was analyzed as follows: A Panalytical X'Pert PRO X-ray diffractometer was used to measure the composition and relative content of the minerals contained in the solid sample, primarily including quartz, feldspar, calcite, gypsum, and other minerals. A Nova Nano SEM450 scanning electron microscope was used to observe the microscopic morphology of the solid sample.

[0090] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Any content not described in detail in the present invention may be adapted from existing technologies.

Claims

1. A device for dynamic leaching experiment on the formation and evolution of groundwater in unsaturated zone, characterized by: The device comprises a water supply tank (2), a liquid outlet valve (3), a liquid outlet pipe (4), a spray (5), an organic glass experimental column (6), a solid sample sampling port (7), a filter layer (8), a liquid sample sampling valve (10), an organic glass bottom column (11) and an experimental stand (20). The bottom of the water supply tank (2) is installed on the left side of the experimental stand (20). The right side of the water supply tank (2) is connected to one end of the liquid outlet valve (3). The other end of the liquid outlet valve (3) is connected to one end of the liquid outlet pipe (4). The other end of the liquid outlet pipe (4) is connected to the inlet of the spray (5). The nozzle of the spray (5) is covered on the top of the organic glass experimental column (6). The side wall of the organic glass experimental column (6) is provided with a solid sample sampling port (7). The bottom of the organic glass experimental column (6) is provided with a filter layer (8). The bottom of the organic glass experimental column (6) is provided with an organic glass bottom column (11). The side wall of the organic glass bottom column (11) is provided with a liquid sample sampling port. A liquid sample sampling valve (10) is installed on the sample sampling port; a water tank top cover (1) is provided on the top of the water supply tank (2), and a water tank cleaning valve (22) is provided on the bottom of the water supply tank (2); a circulating water tank (17) is provided in the frame on the right side of the experimental bench (20) and below the organic glass bottom column (11), and the circulating water tank (17) is connected to the organic glass experimental column (6) through a connecting hose (13); a circulating valve (12) is provided at the bottom of the organic glass experimental column (6), and the circulating valve (12) is connected to one end of the connecting hose (13), and the other end of the connecting hose (13) is connected to the circulating valve (12) through a thread; a circulating water tank top cover (14) is provided on the top of the circulating water tank (17), and one end of the connecting hose (13) passes through the circulating water tank top cover (14) and is inserted into the circulating water tank (17); an automatic float valve (15) is installed inside the circulating water tank (17); a peristaltic pump (18) is provided between the circulating water tank (17) and the water supply tank (2).

2. The device for dynamic leaching experiment of formation and evolution law of unsaturated zone groundwater according to claim 1, characterized in that: The peristaltic pump (18) is installed in the frame at the bottom left side of the experimental bench (20).

3. The device for dynamic leaching experiment of formation and evolution law of unsaturated zone groundwater according to claim 2, characterized in that: The inlet of the peristaltic pump (18) is connected to the circulating water tank (17) via a circulating pipe (16).

4. The device for dynamic leaching experiment of formation and evolution of groundwater in unsaturated zone according to claim 3, characterized in that: The peristaltic pump (18) is connected to the water supply tank (2) via a liquid return pipe (19).

5. The device for dynamic leaching experiment of formation and evolution law of unsaturated zone groundwater according to claim 4, characterized in that: A peristaltic pump control switch (21) is provided on the left middle frame of the experimental bench (20), one end of the peristaltic pump control switch (21) is connected to the control end of the peristaltic pump (18) through a cable, and the other end of the peristaltic pump control switch (21) is connected to the power supply through a cable.

6. The device for dynamic leaching experiment of formation and evolution of groundwater in unsaturated zone according to claim 5, characterized in that: The filter layer (8) is composed of a nylon layer, a quartz sand layer, and a nylon layer from top to bottom.

7. The device for dynamic leaching experiment of formation and evolution of groundwater in unsaturated zone according to claim 6, characterized in that: The side wall of the organic glass experimental column (6) is evenly spaced from top to bottom with a plurality of solid sample sampling ports (7).

8. The device for dynamic leaching experiment on formation and evolution of groundwater in unsaturated zone according to claim 7, characterized in that: The bottom of the organic glass experimental column (6) and the top of the organic glass bottom column (11) are connected via a connecting flange (9).

9. A method for conducting a dynamic leaching experiment on the formation and evolution of groundwater in an unsaturated zone using the dynamic leaching experimental device according to any one of claims 4 to 8, characterized in that: The method specifically comprises the following steps: Step 1: Select a sampling location in the study area and collect solid samples at the sampling point; Step 1 is as follows: We collected historical geological, hydrological, and satellite imagery data from the study area and conducted field research based on the collected data. We selected representative sampling locations in the upper, middle, and lower reaches of the valley in the study area. Sediments from these three sampling locations were collected as solid samples for the dynamic leaching experiment. After collecting the solid samples, the three sediments were air-dried, cleaned, and stored in bags under the same natural conditions. Step 2: Measure and analyze the solid samples collected at different locations in Step 1. Step 2 is as follows: The sediment solid samples collected in step 1 above from different locations in the study area, including the upstream, midstream, and downstream valleys, were subjected to X-ray diffraction analysis to measure the mineral composition and content of the sediment solid samples at different locations. Scanning electron microscopy analysis was also performed to analyze the microstructure of the sediment solid samples at different locations. Step 3: Perform a cyclic leaching experiment on the solid samples collected and analyzed at different locations in Step 2 to dynamically simulate the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock formation during lateral runoff after the infiltration of atmospheric water or surface water into the unsaturated zone. Step 3 is specifically as follows: Step 3.1, a solid sample is placed in the organic glass experimental column (6) of the dynamic leaching experimental device, and deionized water is placed in the water supply tank (2); Step 3.2, the water supply tank (2) supplies deionized water into the organic glass experimental column (6); Step 3.3, starting the peristaltic pump (18), and the deionized water flowing out of the organic glass experimental column (6) is circulated and leached in the dynamic leaching experimental device in turn; Step 3.4, regularly opening the liquid sample sampling valve (10) to perform liquid sample sampling and testing, thereby dynamically simulating the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock layer during the lateral runoff process after the atmospheric water or surface water infiltrates the unsaturated zone; Step 4: Conduct a common leaching experiment on the solid samples collected and analyzed at different locations in Step 2 using the above-mentioned dynamic leaching experimental device to dynamically simulate the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock formation during the vertical infiltration process after infiltration of the unsaturated zone, and study the formation mechanism of groundwater in the unsaturated zone. The specific details of Step 4 are as follows: Step 4.1, cleaning the dynamic leaching experimental device after the reaction in step 3; Step 4.2: Place a solid sample into the organic glass experimental column (6) of the dynamic leaching experimental device, and place deionized water into the water supply tank (2) to carry out a normal leaching experiment; Step 4.3, the water supply tank (2) supplies deionized water to the organic glass experimental column (6); the deionized water flowing out of the organic glass experimental column (6) is leached normally in the dynamic leaching experimental device; Step 4.4, regularly open the liquid sample sampling valve (10) to conduct liquid sample sampling and testing, thereby dynamically simulating the water-rock interaction between atmospheric water or surface water and the unsaturated zone rock layer during the vertical infiltration process after infiltration into the unsaturated zone, and studying the formation mechanism of unsaturated zone groundwater.

10. The method for dynamic leaching experiment on formation and evolution of groundwater in unsaturated zone according to claim 9, characterized in that: The step 3.1 is specifically as follows: a solid sample is placed in the organic glass experimental column (6) of the dynamic leaching experimental device, and deionized water is placed in the water supply tank (2) of the dynamic leaching experimental device to carry out a circulating leaching experiment.

11. The method for dynamic leaching experiment of formation and evolution of groundwater in unsaturated zone according to claim 10, characterized in that: The specific steps of step 3.2 are as follows: open the liquid outlet valve (3), close the liquid sample sampling valve (10), open the circulation valve (12), and the deionized water in the water supply tank (2) enters the organic glass experimental column (6) through the liquid outlet pipe (4) and the spray (5).

12. The method for dynamic leaching experiment of formation and evolution of groundwater in unsaturated zone according to claim 11, characterized in that: The step 3.3 is specifically as follows: turn on the peristaltic pump control switch (21), the peristaltic pump (18) is started, and the deionized water in the organic glass experimental column (6) is filtered through the filter layer (8) under the action of the peristaltic pump (18). After filtration, the deionized water flows through the organic glass bottom column (11), the connecting hose (13), the circulating water tank (17), the circulating pipe (16), the peristaltic pump (18), the return pipe (19) and enters the water supply tank (2), and then continues to repeat steps 3.2 to 3.3 to achieve cyclic leaching.

13. The method for dynamic leaching experiment of formation and evolution of groundwater in unsaturated zone according to claim 12, characterized in that: The step 3.4 is specifically as follows: at regular intervals, the peristaltic pump (18) stops working, the liquid sample sampling valve (10) is opened, the reaction liquid sample is taken out, and the collected reaction liquid sample is sealed and stored in a polyethylene sampling bottle.

14. The method for dynamic leaching experiment on formation and evolution of groundwater in unsaturated zone according to claim 13, characterized in that: The specific steps of step 4.3 are as follows: open the liquid outlet valve (3), open the liquid sample sampling valve (10), and close the circulation valve (12); the deionized water in the water supply tank (2) enters the organic glass experimental column (6) through the liquid outlet pipe (4) and the spray (5), and flows into the organic glass bottom column (11) after being filtered through the filter layer (8).

15. The method for dynamic leaching experiment on formation and evolution of groundwater in unsaturated zone according to claim 14, characterized in that: The step 4.4 is specifically as follows: at regular intervals, the liquid sample sampling valve (10) is opened to take out the post-reaction liquid sample, and the collected post-reaction liquid sample is sealed and stored in a polyethylene sampling bottle.

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