Aquifer blockage indoor simulation experimental device and use method

Abstract

The present invention relates to the field of hydrogeology and environmental science experimental technology, and specifically to an indoor simulation experimental device for aquifer blockage and a method for using the device. An indoor simulation experimental device for aquifer blockage comprises a controller, a simulation sand box, a water supply device, a drainage device, a simultaneous sampling device, and a pressure measuring device; the method for using the device comprises the steps of simultaneously sampling water samples, real-time monitoring of the pressure and deformation of the aquifer, and sampling through a sampling tube after the reinjection experiment is completed. The present invention can simulate the spatial variation characteristics and laws of aquifer blockage during the artificial reinjection of aquifers, and analyze the mechanism of aquifer blockage.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogeology and environmental science experiments, and in particular to an indoor simulation experiment device for aquifer blockage and a use method thereof. Background Art

[0002] With the continuous growth of the world population, the rapid development of social economy and the increasing water demand have led to an increasing contradiction between water supply and demand. Groundwater pollution, groundwater environment deterioration and environmental geological problems have continued to occur. When the natural recharge of groundwater is far less than the actual extraction, the water level of the underground aquifer continues to decline, forming a groundwater drop funnel, and even causing geological disasters such as ground subsidence. The sustainable utilization of groundwater resources faces huge challenges. While reducing the amount of groundwater extraction, the artificial recharge of groundwater aquifers can accelerate the realization of the balance of groundwater extraction and recharge in local areas. Although artificial recharge of aquifers has many advantages, the blockage of aquifers caused by the recharge process seriously affects the recharge efficiency, maintenance cost and service life. Indoor simulation experiments are an important method for analyzing the dynamic characteristics of the artificial recharge of groundwater aquifers and the blockage mechanism. However, at present, most groundwater recharge devices are based on one-dimensional sand columns, which cannot simulate the blockage of aquifers in actual recharge projects, which brings inconvenience to related research and engineering technology problem solving. Therefore, it is of great significance to design an experimental sand box to simulate aquifer blockage during artificial recharge of aquifers, analyze the spatial variation characteristics and laws of aquifer blockage, and reveal the mechanism of aquifer blockage. Summary of the invention

[0003] The invention provides an indoor simulation experimental device for aquifer blockage and a method for using the device. The invention can simulate the spatial variation characteristics and laws of aquifer blockage during artificial recharge of aquifers and analyze the aquifer blockage mechanism.

[0004] To achieve the above object, the technical solution of the present invention is:

[0005] An indoor simulation experimental device for aquifer blockage comprises a controller, a simulation sand box, a water supply device, a drainage device, a simultaneous sampling device, and a pressure measuring device. A simulation area is formed in the simulation sand box by two longitudinally arranged partitions. Aquifers and aquicludes are formed in the simulation area by fillers. A recharge well is formed on one side of the simulation area. The water supply device is connected to the recharge well. A water outlet bin is formed on the other side of the simulation area. The water outlet bin is connected to the drainage device. Two side walls of the simulation area except the partition are formed by the side walls of the simulation sand box. A plurality of pressure measuring holes are evenly arranged on one side wall. The pressure measuring holes are connected to the pressure measuring device. The other side wall is connected to the pressure measuring device. A plurality of water sampling holes are evenly arranged on the wall, and the water sampling holes are connected to the simultaneous sampling device. A plurality of water inlet holes are evenly distributed on the partition facing the recharging well side, and a plurality of water outlet holes are evenly distributed on the partition facing the water outlet bin side. The water inlet holes, water outlet holes, water sampling holes, and pressure measuring holes are all provided with metal filters. A plurality of sampling tube guide holes are arranged in sequence at the top of the simulation sand box relative to the simulation area. The controller is electrically connected to the power supply and is configured to control the water supply device, the drainage device, the simultaneous sampling device, and the pressure measuring device. The pressure measuring device is connected to a data collection and processing mechanism via a wire.

[0006] Preferably, the simulation sand box is a cubic box, the side walls and top wall of the box are made of transparent acrylic material, the two partitions are arc-shaped plates and are parallel to each other, the simulation area is an arc-shaped area, and the two ends of one partition are sealed and fixedly connected to the inner sides of the relative corners of the simulation sand box, and there are 40 pressure measuring holes and water sampling holes, respectively. The 40 pressure measuring holes, 40 water sampling holes, a number of water inlet holes, and a number of water outlet holes are arranged in a matrix, and a number of sampling tube guide holes are arranged uniformly along the radial direction of the arc-shaped area.

[0007] Preferably, the simulation area is composed of a submerged aquifer, a first impermeable layer, a first confined aquifer, a second impermeable layer, and a second confined aquifer from top to bottom in sequence through fillers.

[0008] Preferably, the water supply device includes a water supply tank, a cart, a first flow sensor, and a first pump body. A cart is provided at the bottom of the water supply tank. The water supply tank is connected to the top of the recharge well through a first connecting pipe. The first connecting pipe is provided with a first pump body and a first flow sensor. The first pump body and the first flow sensor are electrically connected to the controller through wires, respectively.

[0009] Preferably, the drainage device includes an electric lifting water head control device and a tailwater storage tank, the electric lifting water head control device includes a linear drive mechanism arranged longitudinally on the outer surface of the side wall of the simulated sand box, the linear drive mechanism is connected to a second pump body, the water inlet end of the second pump body is upward and connected to a U-shaped tube, one end of the U-shaped tube is connected to the second pump body, and the other end is inserted into the water outlet bin, a grating ruler is arranged longitudinally on the side wall of the water outlet bin, the outer wall of one end of the U-shaped tube located in the water outlet bin is connected to the reading head of the grating ruler, and the U-shaped tube is located at one end in the water outlet bin. The outer wall on the other side is connected to a guide rod extending downward in the longitudinal direction through a connecting plate. The upper end fixed sleeve of the guide rod is provided with an annular pressure sensor, and the lower end sliding sleeve is provided with a buoyancy block. An extrusion spring is provided between the buoyancy block and the working end of the annular pressure sensor and located on the outer periphery of the guide rod. In the initial state, the bottom end of the buoyancy block is flush with one end of the U-shaped tube located in the water outlet bin. The water outlet end of the second pump body is connected to the tailwater storage tank through a second connecting pipe. The annular pressure sensor, grating scale, second pump body, and linear drive mechanism are electrically connected to the controller through wires.

[0010] Preferably, the simultaneous sampling device includes a vacuum pump, a third connecting pipe, a fourth connecting pipe, a bracket, and a transverse pipe. The bracket is composed of two vertical pipes, and both ends of the vertical pipe facing the vacuum pump are closed. A number of transverse pipes are sequentially connected between the two vertical pipes from top to bottom. The end of the transverse pipe facing the vacuum pump is connected to the vertical pipe on the same side. A first connecting pipe is provided on the pipe wall of each transverse pipe facing the simulated sand box. The first connecting pipe is connected to the water sampling hole through a fourth connecting pipe. Solenoid valves are respectively provided at both ends of the transverse pipe. A second connecting pipe is provided on the pipe wall of the vertical pipe facing the vacuum pump. The vacuum pump is connected to the second connecting pipe through the third connecting pipe. A pressure control valve is provided on the third connecting pipe. A third connecting pipe is provided under each transverse pipe. A sampling bottle is connected to the lower end of the third connecting pipe. A second flow sensor is also provided on the third connecting pipe. The solenoid valve, vacuum pump, and second flow sensor are electrically connected to the controller through wires.

[0011] Preferably, the pressure measuring device includes a fifth connecting pipe, a pressure measuring plate, and a pressure measuring tube. A plurality of pressure measuring tubes are distributed longitudinally on the side pressure plate, and each pressure measuring tube is connected to the pressure measuring hole through the fifth connecting pipe. The inner ports of the pressure measuring hole and the water sampling hole are provided with cannulas extending into the simulated sand box, and the cannulas have the same length.

[0012] Preferably, the pressure measuring tubes are added with insoluble color reagents, namely speckles, and the data collection and processing mechanism includes a digital speckle meter and a computer. The digital speckle meter obtains the pressure change information of the pressure measuring tube by digitally processing the speckle image. The computer is electrically connected to the digital speckle meter and draws a pressure measurement data curve through a preset program.

[0013] A method for using an indoor simulation experimental device for aquifer blockage includes the following steps:

[0014] Step 1: Preparation: Lay the aquifer (with sand as filler) and the aquiclude (with clay as filler) in the simulation area of ​​the simulated sand box as required, and configure the water source as required; Test the water quality and microbial community characteristics of the water source, as well as the mineral composition, structure and microbial community characteristics of the aquifer medium before the experiment, so as to facilitate comparative analysis of the aquifer blockage mechanism after the experiment;

[0015] Step 2, prepare an indoor simulation experimental device for aquifer blockage, fully connect all devices, and ensure that all components are intact and usable;

[0016] Step 3, adjust the electric water level controller, set the water level of the water outlet tank according to the experimental requirements, the water supply tank starts to supply water, and the water supply flow rate is controlled by the first flow sensor and the first pump body;

[0017] Step 4: When the pressure data in the piezometric tube is observed to be stable, the digital speckle meter and the computer are turned on to start recording the pressure data, and then the artificial recharging of the aquifer is continued, and the pressure data is continued to be recorded;

[0018] Step 5, water sample collection, according to the experimental design, water samples are sampled at different time periods; when sampling, the vacuum pump and the electromagnetic valves on the side of each horizontal tube facing the vacuum pump are turned on, and after the sampling bottle is evacuated, the electromagnetic valve on the other side is opened, and the water samples at each water sampling hole flow into each sampling bottle at the same time. After the data detected by the second flow sensor shows that the sampling bottle is loaded with a certain amount of water sample, the electromagnetic valves and vacuum pumps at both ends of the horizontal tube are closed, and each sampling bottle is manually removed. After sampling, the water quality and microbial community characteristics of the water sample are tested;

[0019] Step 6: After the reinjection experiment is completed, the water supply is stopped, the digital speckle analyzer and the computer are turned off, and a sampling tube is inserted longitudinally from the sampling tube guide hole at the top of the simulated sand box. Sand and soil from each aquifer are collected through the sampling tube, and the sand and soil from the aquifers are stored in sections to test their structure, mineral composition, and microbial community characteristics.

[0020] Step 7: Based on the relevant data on water pressure, mineral composition, and microbial community characteristics obtained during the experiment, combined with the mineral composition, structure, and microbial community characteristics of the aquifer obtained before the experiment, analyze the spatial variation characteristics and laws of aquifer blockage to further reveal the aquifer blockage mechanism.

[0021] Preferably, in the step 3, the method for setting the water level in the water outlet bin according to the experimental requirements is: the controller starts the linear drive mechanism based on the data of the grating ruler, and moves one end of the U-shaped tube located in the water outlet bin to the required set water level height. When the water level is higher than the set water level, the buoyancy block floats up and applies pressure to the annular pressure sensor through the extrusion spring. The controller starts the second pump body based on the pressure information of the annular pressure sensor to pump excess water in the water outlet bin to the tail water collection tank.

[0022] Preferably, in the steps 1, 5, 6 and 7, measuring water quality refers to: measuring one or more of K+, Na+, Ca2+, Mg2+, SO42-, HCO3-, Cl- and NO3-, NH4+, COD and BOD in the water; measuring mineral composition refers to: measuring the type and content of one or more components in quartz, chalcedony, calcite, dolomite, aragonite and gypsum in the sample; measuring mineral structure refers to: measuring the shape, size and morphology characteristics of minerals in the sample; microbial community characteristics refer to: diversity, composition and structural characteristics of bacterial communities.

[0023] Preferably, in step 7, the method for analyzing the spatial variation characteristics and laws of aquifer blockage is as follows: analyzing the changes in the spatial permeability of the aquifer through the spatial distribution characteristics of the pressure data to reveal the spatial variation of blockage in the aquifer; revealing the impact of chemical blockage on aquifer blockage by analyzing the change characteristics of the recharge water quality and the water quality in the aquifer and in the tail water; revealing the impact of microbial blockage on aquifer blockage by analyzing the changes in the diversity composition and structural characteristics of the microbial community; and comprehensively analyzing to reveal the spatial variation characteristics and laws of aquifer blockage during artificial recharge of the aquifer.

[0024] The present invention provides an indoor simulation experimental device for aquifer blockage and a method for using the same, which has the following beneficial effects:

[0025] The present invention can simulate the spatial variation characteristics and laws of aquifer blockage during artificial recharge of aquifers, analyze the aquifer blockage mechanism, and provide a theoretical basis for solving related research and engineering technical problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0027] Figure 2 It is a structural schematic diagram of the electric lifting water head control device of the present invention.

[0028] Figure 3 It is a schematic diagram of the local structure of location A of the present invention.

[0029] In the figure: 1-simulated sand box, 2-electric lifting and water head control device, 201-second pump body, 202-U-shaped tube, 203-grating ruler, 204-reading head, 205-connecting plate, 206-guide rod, 207-extrusion spring, 208-annular pressure sensor, 209-buoyancy block, 3-electric switch, 4-linear drive mechanism, 401-screw, 402-guide rail, 403-fixed plate, 404-drive motor, 405-moving seat, 5-diving aquifer, 6-first impermeable layer, 7-first pressure aquifer, 8-sampling tube guide hole, 9-surface sand, 10-recharge well, 11-pressure measuring hole, 12 —second aquifer, 13—second pressure-bearing aquifer, 14—tailwater storage tank, 15—second connecting pipe, 16—pressure plate, 17—pressure tube, 18—insoluble color reagent, 19—pressure plate bracket, 20—fifth connecting pipe, 21—digital speckle meter, 22—computer, 23—water supply tank, 24—trolley, 25—first flow sensor, 26—first connecting pipe, 27—vacuum pump, 28—water storage barrel, 29—faucet, 30—pressure control valve, 31—cross pipe, 32—fourth connecting pipe, 33—water sampling hole, 34—sampling bottle, 35—second flow sensor, 36—water outlet bin, 37—bracket. DETAILED DESCRIPTION

[0030] The following describes in detail the implementation mode of the present invention in a step-by-step manner. The description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0031] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “top”, “bottom”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the purpose of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, and a specific direction structure and operation, and therefore cannot be understood as a limitation on the present invention.

[0032] An indoor simulation experimental device for aquifer blockage, such as Figure 1-3As shown, it includes a controller (a commonly used device, not shown in the figure), a simulation sand box 1, a water supply device, a drainage device, a simultaneous sampling device, and a pressure measuring device. The simulation sand box 1 is formed with two longitudinally arranged partitions to form a simulation area, and the simulation area is formed with aquifers and aquicludes by fillers. One side of the simulation area constitutes a recharge well 10, and the water supply device is connected to the recharge well 10. The other side of the simulation area constitutes a water outlet bin 36, and the water outlet bin 36 is connected to the drainage device. The two side walls of the simulation area except the partition are composed of the side walls of the simulation sand box 1, and a plurality of pressure measuring holes 11 are evenly arranged on one side wall, and the pressure measuring holes 11 are connected to the pressure measuring device. A plurality of water sampling holes 11 are evenly arranged on the other side wall. Hole 33, the water sampling hole 33 is connected to the simultaneous sampling device, a plurality of water inlet holes are evenly distributed on the baffle plate facing the recharging well 10 side (a common structure, not shown in the figure), a plurality of water outlet holes are evenly distributed on the baffle plate facing the water outlet bin 36 side (a common structure, not shown in the figure), the water inlet hole, the water outlet hole, the water sampling hole 33, and the pressure measuring hole 11 are all provided with metal filter screens, a plurality of sampling tube guide holes 8 are arranged in sequence at the top of the simulation sand box 1 relative to the simulation area, the controller is electrically connected to the power supply, and is configured to control the water supply device, the drainage device, the simultaneous sampling device, and the pressure measuring device, and the pressure measuring device is connected to a data collection and processing mechanism through a wire.

[0033] like Figure 1 As shown, the simulation sand box 1 is a cubic box, the side walls and top wall of the box are made of transparent acrylic material, the two partitions are arc-shaped plates and are parallel to each other, the simulation area is an arc-shaped area, and the two ends of one partition are sealed and fixedly connected to the inner sides of the relative corner edges of the simulation sand box 1, and there are 40 pressure measuring holes 11 and water sampling holes 33 respectively. The 40 pressure measuring holes 11, 40 water sampling holes 33, a number of water inlet holes, and a number of water outlet holes are arranged in a matrix, and a number of sampling tube guide holes 8 are uniformly arranged in sequence along the radial direction of the arc-shaped area.

[0034] like Figure 1 As shown, the simulation area is formed from top to bottom by fillers in turn into a submerged aquifer 5, a first impermeable layer 6, a first confined aquifer 7, a second impermeable layer 12, and a second confined aquifer 13. Figure 1 As shown, a surface layer of sand 9 is also provided on the top of the submerged aquifer 5 .

[0035] like Figure 1As shown, the water supply device includes a water supply tank 23, a trolley 24, a first flow sensor 25, and a first pump body (a commonly used structure, not shown in the figure). A trolley 24 is provided at the bottom of the water supply tank 23 for easy movement. The water supply tank 23 is connected to the top of the recharge well 10 through a first connecting pipe 26. The first connecting pipe 26 is provided with a first pump body and a first flow sensor 25. The first pump body and the first flow sensor 25 are electrically connected to the controller through wires.

[0036] like Figure 1-3 As shown, the drainage device includes an electric lifting water head control device and a tailwater storage tank, the electric lifting water head control device includes a linear drive mechanism 4 arranged longitudinally on the outer surface of the side wall of the simulated sand box 1, the linear drive mechanism 4 is connected to the second pump body 201, the water inlet end of the second pump body 201 is upward and connected to a U-shaped tube 202, one end of the U-shaped tube 202 is connected to the second pump body 201, and the other end is inserted into the water outlet bin 36, a grating ruler 203 is longitudinally arranged on the side wall of the water outlet bin 36, the outer wall of one end of the U-shaped tube 202 located in the water outlet bin 36 is connected to the reading head 204 of the grating ruler 203, and the outer wall of the other side of one end of the U-shaped tube 202 located in the water outlet bin 36 is connected to the reading head 204 of the grating ruler 203. The wall is connected to a guide rod 206 extending downward in the longitudinal direction through a connecting plate 205. The upper end of the guide rod 206 is fixedly sleeved with an annular pressure sensor 208, and the lower end is slidingly sleeved with a buoyancy block 209. An extrusion spring 207 is sleeved between the buoyancy block 209 and the working end of the annular pressure sensor 208 and located on the outer periphery of the guide rod 206. In the initial state, the bottom end of the buoyancy block 209 is flush with one end of the U-shaped tube 202 located in the water outlet bin 36. The water outlet end of the second pump body 201 is connected to the tailwater storage tank 14 through the second connecting pipe 15. The annular pressure sensor 208, the grating ruler 203, the second pump body 201, and the linear drive mechanism are electrically connected to the controller through wires respectively.

[0037] In this embodiment, the linear drive mechanism 4 may be a ball screw structure or other devices in the prior art that can achieve related functions, such as Figure 2 As shown, the ball screw structure (the specific structural principle is not described in detail) includes: a screw 401, a guide rail 402, a fixed plate 403, a drive motor 404, and a moving seat 405. The drive motor drives the moving seat to drive the second pump body to move up and down along the guide rail, so that the water suction end of the U-shaped tube 202 can be adjusted up and down in the water outlet bin. Combined with the grating ruler, the water level in the water outlet bin can be accurately controlled.

[0038] like Figure 1As shown, the simultaneous sampling device includes a vacuum pump 27, a third connecting pipe, a fourth connecting pipe 32, a bracket 37, and a transverse pipe 31. The bracket 37 is composed of two vertical pipes, and both ends of the vertical pipe facing the vacuum pump 27 are closed. A plurality of transverse pipes 31 are sequentially connected between the two vertical pipes from top to bottom. One end of the transverse pipe 31 facing the vacuum pump 27 is connected to the vertical pipe on the same side. A first connecting pipe is provided on the pipe wall of each transverse pipe 31 facing the simulated sand box 1. The first connecting pipe is connected to the water sampling hole 33 through the fourth connecting pipe 32. Both ends of the transverse pipe 31 are connected to the water sampling hole 33. A solenoid valve (a common structure, not shown in the figure) is respectively provided, a second connecting pipe (not shown in the figure) is provided on the vertical pipe wall facing the vacuum pump 27, the vacuum pump 27 is connected to the second connecting pipe through a third connecting pipe (not marked in the figure), a pressure control valve 30 is provided on the third connecting pipe, a third connecting pipe is respectively provided under each horizontal pipe 31, a sampling bottle 34 is connected to the lower end of the third connecting pipe, and a second flow sensor 35 is also provided on the third connecting pipe, the solenoid valve, the vacuum pump 27, and the second flow sensor 35 are respectively electrically connected to the controller through wires; Figure 1 As shown, a faucet 29 is provided at the bottom of the vertical pipe near the vacuum pump, and a water storage bucket 28 is provided below the faucet 29;

[0039] In the present embodiment, it should be noted that simultaneous sampling is particularly important for the blockage analysis of aquifers. The reason is that when the pressure data detected by the pressure measuring tube is stable, it means that the water infiltration flow state in the aquifer has become stable. However, due to the existence of blockage, the water quality of the water collected by adjacent water sampling holes will be very different. For example, the concentration of a certain type of mineral in the water sample collected in the left water sampling hole is much lower than the detection data of the water sample collected in the adjacent right water sampling hole, which means that there is a more serious blockage in the aquifer between the two water sampling holes, and the severity of the blockage can be judged according to the size of the concentration difference; however, if the water samples are not sampled at the same time, the following problem will occur: that is, water infiltration occurs between the two adjacent water sampling holes due to the time difference in sampling, and the data collected by the two are not the data at the same time. There is a possibility that due to the time difference, there is no significant difference in mineral concentration in the water samples collected by the two or the difference is greater than the actual value, which can easily lead to a misjudgment of the degree of blockage of the aquifer. Since the blockage degree of the aquifer is a dynamic process, sampling at each preset time is of great significance for judging the blockage state of the aquifer and the evolution trend of the blockage state. At the same time, since the present invention is provided with 40 water sampling holes, a wide range of monitoring and analysis can be performed on the blockage of the aquifer, so that the law of aquifer blockage can be studied through simulation experiments.

[0040] like Figure 1As shown, the pressure measuring device includes a fifth connecting pipe 20, a pressure measuring plate 16, and a pressure measuring tube 17. A plurality of pressure measuring tubes 17 are longitudinally distributed on the side pressure plate 16. Each pressure measuring tube 17 is connected to the pressure measuring hole 11 through the fifth connecting pipe 20. The inner ports of the pressure measuring hole 11 and the water sampling hole 33 are provided with cannulas (not shown) extending into the simulation sand box 1. The cannulas have the same length.

[0041] In this embodiment, the purpose of providing the cannula is to avoid the collected water sample being the water sample in the gap between the filler and the side wall of the simulated sand box, which would result in loss of identification significance due to the mutual circulation between the water samples; similarly, it also avoids the detected pressure being the pressure in the gap between the filler and the simulated sand box, which would result in the measured pressure value losing practical significance due to the circulation of water in the gap.

[0042] like Figure 1 As shown, the pressure measuring tube 17 is added with an insoluble color reagent 18, namely, speckle, and the data collection and processing mechanism includes a digital speckle instrument and a computer. The digital speckle instrument obtains the pressure change information of the pressure measuring tube by digitally processing the speckle image. The computer is electrically connected to the digital speckle instrument and draws a pressure measurement data curve through a preset program;

[0043] In this embodiment, by setting up 40 pressure measuring holes, the pressure and deformation of the aquifer between adjacent pressure measuring holes can be monitored, and the local blockage of the aquifer can be analyzed based on the pressure difference and deformation. Furthermore, through the pressure difference and deformation at the aquifer connected to the 40 pressure measuring holes, the blockage and deformation of the aquifer can be analyzed over a large range. By continuously monitoring the pressure and deformation, the spatial variation characteristics and laws of the aquifer blockage can be simulated, further revealing the blockage mechanism of the aquifer.

[0044] A method for using an indoor simulation experimental device for aquifer blockage, such as Figure 1-3 As shown, the following steps are included:

[0045] Step 1, preparation work, laying the aquifer (whose filler is sand) and the aquiclude (whose filler is clay) in the simulation area of ​​the simulated sand box 1 as required, and configuring the water supply source as required; before the experiment, test the water quality of the water supply source, the characteristics of the microbial community, and the mineral composition, structure and microbial community characteristics of the aquifer medium, so as to facilitate comparative analysis of the aquifer blockage mechanism after the experiment;

[0046] Step 2, prepare an indoor simulation experimental device for aquifer blockage, fully connect all devices, and ensure that all components are intact and usable;

[0047] Step 3, adjust the electric water level controller, set the water level of the water outlet tank according to the experimental requirements, the water supply tank starts to supply water, and the water supply flow rate is controlled by the first flow sensor and the first pump body;

[0048] Step 4: When the pressure data in the pressure measuring tube is stable, the digital speckle meter and the computer are turned on to start recording the pressure data, and then the artificial recharging of the aquifer is continued, and the pressure data is continued to be recorded;

[0049] Step 5, water sample collection, according to the experimental design, water samples are sampled at different time periods; when sampling, the vacuum pump and the electromagnetic valves on the side of each horizontal tube facing the vacuum pump are turned on, and after the sampling bottle is evacuated, the electromagnetic valve on the other side is opened, and the water samples at each water sampling hole flow into each sampling bottle at the same time. After the data detected by the second flow sensor shows that the sampling bottle is loaded with a certain amount of water sample, the electromagnetic valves and vacuum pumps at both ends of the horizontal tube are closed, and each sampling bottle is manually removed. After sampling, the water quality and microbial community characteristics of the water sample are tested;

[0050] Step 6: After the reinjection experiment is over, stop the water supply, turn off the digital speckle analyzer and the computer, insert a sampling tube (not shown in the figure, an empty tube structure with a detachable outer wall, such as a tube wall made of two semicircular tubes) longitudinally from the sampling tube guide hole 8 at the top of the simulated sand box 1, collect sand and soil from each aquifer through the sampling tube, store the extracted aquifer sand and soil in sections, and test its structure, mineral composition, and microbial community characteristics;

[0051] Step 7: Based on the relevant data on water pressure, mineral composition, and microbial community characteristics obtained during the experiment, combined with the mineral composition, structure, and microbial community characteristics of the aquifer obtained before the experiment, analyze the spatial variation characteristics and laws of aquifer blockage to further reveal the aquifer blockage mechanism.

[0052] like Figure 1-3 As shown, in the step 3, the method for setting the water level of the water outlet bin according to the experimental requirements is: the controller starts the linear drive mechanism based on the data of the grating ruler, and moves one end of the U-shaped tube located in the water outlet bin to the required set water level height. When the water level is higher than the set water level, the buoyancy block floats up and applies pressure to the annular pressure sensor through the extrusion spring. The controller starts the second pump body based on the pressure information of the annular pressure sensor to pump excess water in the water outlet bin 36 to the tail water collection tank.

[0053] like Figure 1-3 As shown, in the steps 1, 5, 6 and 7, measuring water quality refers to: measuring K in water + 、Na + , Ca 2+ Mg 2+ 、SO4 2- 、HCO3 - , Cl - and NO3 - NH4 +, COD, BOD to measure water quality; measuring mineral composition refers to: measuring the type and content of one or more components in quartz, chalcedony, calcite, dolomite, aragonite and gypsum in the sample; measuring mineral structure refers to: measuring the shape, size and morphology of minerals in the sample; microbial community characteristics refer to: bacterial community diversity, composition and structural characteristics.

[0054] like Figure 1-3 As shown, in the step 8, the method for analyzing the spatial variation characteristics and laws of aquifer blockage is as follows: analyzing the changes in the spatial permeability of the aquifer through the spatial distribution characteristics of the pressure data, revealing the spatial variation of blockage in the aquifer; revealing the impact of chemical blockage on aquifer blockage by analyzing the change characteristics of the recharge water quality and the water quality in the aquifer and in the tail water; revealing the impact of microbial blockage on aquifer blockage by analyzing the changes in the diversity composition and structural characteristics of the microbial community; and comprehensively analyzing to reveal the spatial variation characteristics and laws of aquifer blockage during artificial recharge of the aquifer.

Claims

1. An indoor simulation experimental device for aquifer blockage, characterized by: The invention comprises a controller, a simulation sand box, a water supply device, a drainage device, a simultaneous sampling device and a pressure measuring device. The simulation sand box is provided with two longitudinally arranged partitions to form a simulation area. The simulation area is provided with fillers to form an aquifer and an aquiclude. One side of the simulation area forms a recharging well. The water supply device is connected to the recharging well. The other side of the simulation area forms a water outlet bin. The water outlet bin is connected to the drainage device. The two side walls of the simulation area except the partition are formed by the side walls of the simulation sand box. A plurality of pressure measuring holes are evenly arranged on one of the side walls. The pressure measuring hole is connected to the pressure measuring device, and a plurality of water sampling holes are evenly arranged on the other side wall. The water sampling holes are connected to the simultaneous sampling device. A plurality of water inlet holes are evenly distributed on the baffle plate facing the recharging well side, and a plurality of water outlet holes are evenly distributed on the baffle plate facing the water outlet bin side. The water inlet holes, water outlet holes, water sampling holes, and pressure measuring holes are all provided with metal filters. A plurality of sampling tube guide holes are arranged in sequence at the top of the simulation sand box and at a position opposite to the simulation area. The controller is electrically connected to the power supply and is equipped with The device is configured to control the water supply device, the drainage device, the simultaneous sampling device, and the pressure measuring device. The pressure measuring device is connected to a data collection and processing mechanism through a wire. The simultaneous sampling device includes a vacuum pump, a third connecting pipe, a fourth connecting pipe, a bracket, and a transverse pipe. The bracket is composed of two vertical pipes. The two ends of the vertical pipe facing the vacuum pump are closed. A plurality of transverse pipes are sequentially connected between the two vertical pipes from top to bottom. One end of the transverse pipe facing the vacuum pump is connected to the vertical pipe on the same side. A first connecting pipe is provided on the pipe wall of each transverse pipe facing the simulated sand box. The first connecting pipe is connected to the water sampling hole through a fourth connecting pipe. Solenoid valves are provided at both ends of the transverse pipe. A second connecting pipe is provided on the pipe wall of the vertical pipe facing the vacuum pump. The vacuum pump is connected to the second connecting pipe through a third connecting pipe. A pressure control valve is provided on the third connecting pipe. A third connecting pipe is provided under each transverse pipe. A sampling bottle is connected to the lower end of the third connecting pipe. A second flow sensor is also provided on the third connecting pipe. The solenoid valve, the vacuum pump, and the second flow sensor are electrically connected to the controller through wires.

2. The indoor simulation experimental device for aquifer blockage according to claim 1, characterized in that: The simulation sand box is a cubic box, the side walls and top wall of the box are made of transparent acrylic material, the two partitions are arc-shaped plates and are parallel to each other, the simulation area is an arc-shaped area, and the two ends of one partition are sealed and fixedly connected to the inner side of the relative corner edges of the simulation sand box, and there are 40 pressure measuring holes and water sampling holes respectively, 40 pressure measuring holes, 40 water sampling holes, a number of water inlet holes, and a number of water outlet holes are arranged in a matrix, and a number of sampling tube guide holes are uniformly arranged in the radial direction of the arc-shaped area in sequence; The simulation area is composed of a submerged aquifer, a first impermeable layer, a first pressure-bearing aquifer, a second impermeable layer, and a second pressure-bearing aquifer in sequence from top to bottom through fillers.

3. The indoor simulation experimental device for aquifer blockage according to claim 2, characterized in that: The water supply device comprises a water supply tank, a cart, a first flow sensor, and a first pump body. A cart is provided at the bottom of the water supply tank. The water supply tank is connected to the top of the recharging well through a first connecting pipe. A first pump body and a first flow sensor are provided on the first connecting pipe. The first pump body and the first flow sensor are electrically connected to the controller through wires respectively. The drainage device includes an electric lifting water head control device and a tailwater storage tank. The electric lifting water head control device includes a linear drive mechanism arranged longitudinally on the outer surface of the side wall of the simulated sand box. The linear drive mechanism is connected to a second pump body. The water inlet end of the second pump body faces upward and is connected to a U-shaped tube. One end of the U-shaped tube is connected to the second pump body, and the other end is inserted into the water outlet bin. A grating ruler is arranged longitudinally on the side wall of the water outlet bin. The outer wall of one end of the U-shaped tube located in the water outlet bin is connected to the reading head of the grating ruler. The other end of the U-shaped tube located in the water outlet bin is connected to the reading head of the grating ruler. The outer wall of the side is connected to a guide rod extending downward in the longitudinal direction through a connecting plate, the upper end fixed sleeve of the guide rod is provided with an annular pressure sensor, the lower end sliding sleeve is provided with a buoyancy block, and an extrusion spring is provided between the buoyancy block and the working end of the annular pressure sensor and located on the outer peripheral sleeve of the guide rod. In the initial state, the bottom end of the buoyancy block is flush with one end of the U-shaped tube located in the water outlet bin, the water outlet end of the second pump body is connected to the tailwater storage tank through a second connecting pipe, and the annular pressure sensor, grating scale, second pump body, and linear drive mechanism are electrically connected to the controller through wires.

4. The indoor simulation experimental device for aquifer blockage as claimed in claim 3, characterized in that: The pressure measuring device includes a fifth connecting pipe, a pressure measuring plate, and a pressure measuring tube. A plurality of pressure measuring tubes are distributed longitudinally on the pressure measuring plate. Each pressure measuring tube is connected to the pressure measuring hole through the fifth connecting pipe. The inner ports of the pressure measuring hole and the water sampling hole are provided with cannulas extending into the simulated sand box, and the cannulas have the same length.

5. The indoor simulation experimental device for aquifer blockage according to claim 4, characterized in that: Insoluble color reagents are added to the pressure measuring tubes. The data collection and processing mechanism includes a digital speckle meter and a computer. The digital speckle meter obtains pressure change information of the pressure measuring tube by digitally processing the speckle image. The computer is electrically connected to the digital speckle meter and draws a pressure measurement data curve through a preset program.

6. The method for using the indoor simulation experimental device for aquifer blockage as claimed in claim 5, characterized in that: The steps include: Step 1: Preparation: Lay the aquifer and aquiclude in the simulation area of ​​the simulated sand box as required, and configure the water source as required; Test the water quality of the water source, the characteristics of the microbial community, and the mineral composition, structure and microbial community characteristics of the aquifer medium before the experiment, so as to facilitate comparative analysis of the aquifer blockage mechanism after the experiment; Step 2, prepare an indoor simulation experimental device for aquifer blockage, fully connect all devices, and ensure that all components are intact and usable; Step 3, adjust the electric water level controller, set the water level of the water outlet tank according to the experimental requirements, the water supply tank starts to supply water, and the water supply flow rate is controlled by the first flow sensor and the first pump body; Step 4: When the pressure data in the piezometric tube tends to be stable, the digital speckle meter and the computer are turned on to start recording the pressure data, and then the artificial recharging of the aquifer is continued, and the pressure data is continued to be recorded; Step 5, water sample collection, according to the experimental design, water samples are sampled at different time periods; when sampling, the vacuum pump and the electromagnetic valves on the side of each horizontal tube facing the vacuum pump are turned on, and after the sampling bottle is evacuated, the electromagnetic valve on the other side is opened, and the water samples at each water sampling hole flow into each sampling bottle at the same time. After the data detected by the second flow sensor shows that the sampling bottle is loaded with a certain amount of water sample, the electromagnetic valves and vacuum pumps at both ends of the horizontal tube are closed, and each sampling bottle is manually removed. After sampling, the water quality and microbial community characteristics of the water sample are tested; Step 6: After the reinjection experiment is completed, the water supply is stopped, the digital speckle analyzer and the computer are turned off, and a sampling tube is inserted longitudinally from the sampling tube guide hole at the top of the simulated sand box. Sand and soil from each aquifer are collected through the sampling tube, and the sand and soil from the aquifers are stored in sections to test their structure, mineral composition, and microbial community characteristics. Step 7: Based on the relevant data on water pressure, mineral composition, and microbial community characteristics obtained during the experiment, combined with the mineral composition, structure, and microbial community characteristics of the aquifer obtained before the experiment, analyze the spatial variation characteristics and laws of aquifer blockage to further reveal the aquifer blockage mechanism.

7. The method for using the indoor simulation experimental device for aquifer blockage according to claim 6, characterized in that: In the step 3, the method for setting the water level of the water outlet bin according to the experimental requirements is: the controller starts the linear drive mechanism based on the data of the grating ruler, and moves one end of the U-shaped tube located in the water outlet bin to the required set water level height. When the water level is higher than the set water level, the buoyancy block floats up and applies pressure to the annular pressure sensor through the extrusion spring. The controller starts the second pump body based on the pressure information of the annular pressure sensor to pump excess water in the water outlet bin to the tail water storage tank.

8. The method for using the indoor simulation experimental device for aquifer blockage according to claim 7, characterized in that: In the steps 1, 5, 6 and 7, measuring water quality refers to: measuring one or more of K+, Na+, Ca2+, Mg2+, SO42-, HCO3-, Cl- and NO3-, NH4+, COD and BOD in the water; measuring mineral composition refers to: measuring the type and content of one or more components of quartz, chalcedony, calcite, dolomite, aragonite and gypsum in the sample; measuring mineral structure refers to: measuring the shape, size and morphology of minerals in the sample; microbial community characteristics refer to: diversity, composition and structural characteristics of bacterial communities.

9. The method for using the indoor simulation experimental device for aquifer blockage according to claim 8, characterized in that: In step 7, the method for analyzing the spatial variation characteristics and laws of aquifer blockage is as follows: analyzing the changes in the spatial permeability of the aquifer through the spatial distribution characteristics of pressure data to reveal the spatial variation of blockage in the aquifer; revealing the impact of chemical blockage on aquifer blockage by analyzing the change characteristics of the recharge water quality and the water quality in the aquifer and in the tail water; revealing the impact of microbial blockage on aquifer blockage by analyzing the changes in the diversity composition and structural characteristics of the microbial community; and comprehensively analyzing to reveal the spatial variation characteristics and laws of aquifer blockage during artificial recharge of the aquifer.

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