An experimental device and method for simulating water pumping in an inclined borehole

Abstract

The application provides an experimental device and method for simulating a tilted borehole pumping experiment, and relates to the field of hydrogeology, and comprises a sand box part, a water tank part, a pressure measuring tube part and a pumping well part. The sand box part simulates an aquifer, and in the experiment, the simulation of the spatial distribution of the stratum in the actual situation is realized by controlling the particle size and combination of the filler; the water tank part adjusts the water level at both ends of the sand box, and controls the flow state of the groundwater in the sand box by adjusting the relative height of the two side water tanks; the pressure measuring tube part measures the size of the water head pressure of the aquifer at different positions in the sand box, and depicts the flow field of the sand box in the pumping experiment; and the pumping well part is composed of different angle boreholes by the water pump and the filter pipe according to different experimental purposes. The experimental device can be used to obtain the water level change rate and the drawdown funnel scale of the aquifer when the pumping experiment is carried out in different angle boreholes, and can monitor the disturbance state of the flow field in real time.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydrogeology, in particular to an experimental device and method for simulating inclined borehole pumping experiment BACKGROUND

[0002] In the process of solving practical problems such as tunnel gushing water prediction and prevention, geothermal water exploitation and operation, etc., hydrogeological research often relies on the application of rock-soil experimental technology to accurately obtain key hydrogeological parameters such as the flow characteristics of groundwater and the permeability of rock-soil mass, thereby providing a scientific basis for engineering decision-making. The permeability coefficient is usually obtained by using the method of borehole pumping test. Compared with vertical boreholes, inclined boreholes can control more strata with fewer boreholes in areas with complex geological structures. When the strata are located under rivers or streams, it is difficult to carry out vertical borehole pumping test, but inclined boreholes can be drilled to the required strata on both sides of the river or stream. For sensitive ground objects, inclined wells can also be used for corresponding avoidance. The current technical background of inclined hole pumping test directly uses the Dupuit and Thiem formula of vertical well pumping test for parameter calculation in the indoor calculation stage, and lacks effective verification of the parameter calculation method by indoor experiment. In summary, the inclined borehole pumping test has certain research significance. SUMMARY

[0003] Starting from the actual needs encountered in the fields of tunnel gushing water prediction and prevention, geothermal water exploitation, etc., in order to study the disturbance law of inclined borehole pumping test on groundwater flow field and analyze the differences between inclined well and vertical well pumping experiments, the present application provides a convenient and safe experimental device and experimental method for vertical well and inclined well pumping experiments.

[0004] An experimental device for simulating inclined borehole pumping experiment, the experimental device comprising a sand box part A, a water tank part B, a pressure measuring pipe part C and a water pumping pump part D;

[0005] The sand box part A comprises a sand box water stop plate, a sand box water permeable plate, a pressure measuring point, a vertical well, an inclined well and an isolation plate. The sand box water stop plate and the sand box water permeable plate are located at both ends of the sand box part A, and the vertical well and the inclined well are located in the middle of the sand box part A. The sand box part A is used to simulate the aquifer. By controlling the particle size and combination relationship of the filler in the sand box part A, the simulation of the spatial distribution of the strata in the actual situation is realized.

[0006] The water tank part B comprises a left water tank B1 and a right water tank B2, and the sand box part A is connected with the left water tank B1 and the right water tank B2 on both sides respectively. The left water tank B1 comprises a left water tank main body, a left water tank height adjusting screw rod,

[0007] The left sand box inlet valve and the right water tank B2 include the right water tank body, the right water tank height adjustment screw, and the right sand box inlet valve; the water level at both ends of the sand box is adjusted by the water tank part B, and the flow state of groundwater in the sand box is controlled by adjusting the relative height of the two water tanks;

[0008] The pressure gauge section C is used to measure the water head pressure at different locations in the aquifer within the sand box, thus characterizing the flow field within the sand box during the pumping experiment.

[0009] The pumping well section D includes a vertical shaft pumping pipe, an inclined shaft pumping pipe, a pumping pump, and a pumping pump outlet pipe; the pumping well section D is connected to the vertical shaft through the vertical shaft pumping pipe and to the inclined shaft through the inclined shaft pumping pipe; the pumping well section D is used to form boreholes with different inclination angles by pumping pumps and filter pipes according to different experimental purposes.

[0010] Based on the lithological characteristics of the strata, sand samples with different particle size distributions and permeability properties are filled into a sand box. This experimental device enables a scaled-down simulation of the strata in the engineering area. By acquiring the rate of change of water level and the size of the drawdown cone during pumping experiments in boreholes with different inclination angles, the device can monitor the disturbance to the flow field in real time. By conducting sand box pumping experiments, the flow state of groundwater in the sand box is monitored and analyzed, thereby obtaining dynamic distribution data of the flow field and analyzing the differences and patterns of flow field distribution.

[0011] An experimental method for simulating an inclined borehole pumping experiment, implemented based on the aforementioned experimental apparatus, includes the following steps:

[0012] ① Device installation

[0013] Connect the main body of the left water tank to the sand tank via the left water tank sand tank connecting pipe; connect the main body of the right water tank to the sand tank via the right water tank sand tank connecting pipe; connect the pressure measuring pipes at the pressure measuring points in the order from top to bottom and from left to right, and arrange them on the pressure measuring panel.

[0014] ② Sand sample loading

[0015] After the device is installed, sand of the required particle size is sieved through a sand and gravel sieve. The sand is then filled into the sand box on both sides of the isolation plate (6). During filling, the sand should be compacted layer by layer. Different sand filling methods are required to simulate different aquifer conditions. This experiment uses three sand filling modes: uniformly spreading sand and gravel of the same particle size throughout the sand box to simulate homogeneous isotropic aquifer conditions; horizontally filling sand and gravel of different particle sizes into the sand box to simulate horizontally distributed strong and weak interlayered aquifer conditions; and tilting sand and gravel of different particle sizes into the sand box to simulate non-horizontal aquifer conditions. The sand sample is bounded by the permeable plate, the panel where the pressure measuring point is located, and the isolation plate.

[0016] ③ After the sand sample is filled, adjust the height adjustment screws of the left and right water tanks to make the main bodies of the left and right water tanks at the same height. Open the water inlet valves of the left and right sand tanks. The water tank supplies water to the main bodies of the left and right water tanks through the water inlets of the left and right water tanks. The water in the tanks flows to the sand tanks through the connecting pipes of the left and right water tanks, respectively. Under the control of the acrylic perforated plate and the mesh of the permeable plate, the water aquifer of the sand sample is filled with water. When the water level of the aquifer on the left and right sides of the sand tank reaches the height of the overflow plate of the left and right water tanks, respectively, the water level of the left and right water tanks no longer rises. At this time, the water in the left and right water tanks flows out from the overflow outlet of the left and right water tanks, respectively, passing over the overflow plate of the left and right water tanks, respectively, thereby controlling the water level on both sides of the sand tank to remain constant. The permeable plates on the left and right sides are the constant head boundary, and the isolation plate and the panel where the pressure measuring point is located are the water-proof boundary.

[0017] ④ Use a water pump to pump water from the vertical shaft and the inclined shaft. Connect the power supply to the water pump, insert the vertical shaft pumping pipe and the inclined shaft pumping pipe into the vertical shaft and the inclined shaft respectively, set the water pumping flow rate, and start the water pump to pump water from the vertical shaft and the inclined shaft. The water in the vertical shaft and the inclined shaft is discharged through the water pump outlet pipe.

[0018] ⑤ Regularly observe the pressure measuring panel and record the water head of the vertical and inclined wells. Analyze the similarities and differences in the water head change patterns of the vertical and inclined wells during the pumping process. When the water level in the vertical and inclined wells remains stable, observe the pressure measuring panel and record the water head data of the pressure measuring tube. Based on the principle of interpolation, characterize the water head lines and streamlines of the sand box, and analyze whether there are differences in the flow fields of the vertical and inclined wells. If there are no differences, it means that the disturbance of the sand box flow field by the inclined well pumping experiment and the vertical well pumping experiment is consistent. In this case, the permeability coefficient of the aquifer can be obtained directly by the parameter determination method of the vertical well pumping experiment. If there are differences, the correction method and correction coefficient for the parameter determination of the inclined well pumping experiment can be derived by utilizing the difference in the flow fields of the vertical well pumping experiment and the inclined well pumping experiment. The correction method and correction coefficient may differ for different geological structures. Use this device to simulate different geological structures, and finally scale up the laboratory model to the engineering area to realize the parameter determination work of the inclined well pumping experiment in the project.

[0019] ⑥ Stop pumping. When the sand box reaches the initial state again, adjust the pumping flow rate and start pumping. When the water level in the vertical shaft and the inclined shaft is stable, observe the pressure measuring panel, record the pressure head data, and characterize the head line and streamline of the sand box according to the principle of interpolation. Analyze whether there are differences in the flow field between the vertical shaft and the inclined shaft.

[0020] ⑦ Adjust the height adjustment screw of the left water tank to lower the height of the left water tank, causing the water level on the left side of the sand tank to drop. After the water level stabilizes, repeat steps ④-⑥. Adjust the height adjustment screw of the left water tank to restore the water level of the left water tank to be level with the right side. Adjust the height adjustment screw of the right water tank to lower the height of the right water tank, causing the water level on the right side of the sand tank to drop. Repeat steps ④-⑥.

[0021] Considering the actual needs of hydrogeological engineering, sand samples with different particle size distributions and permeability characteristics are filled into sand boxes according to the lithological characteristics of the strata. The experimental device is used to simulate the strata of the engineering area at a scaled-down ratio. By carrying out sand box pumping experiments, the flow state of groundwater in the sand box is monitored and analyzed, thereby obtaining dynamic distribution data of the flow field and analyzing the differences and changes in the flow field distribution.

[0022] The beneficial effects of this invention are as follows: This invention considers the actual needs of hydrogeological engineering, utilizing geological profile data obtained through geophysical exploration (geophysical exploration) and drilling techniques. Based on the lithological characteristics of the strata, sand samples with different particle size distributions and permeability characteristics are filled into a sand box, achieving a proportionally scaled-down simulation of the strata in the engineering area. By controlling the particle size and combination relationship of the filling material, the spatial distribution of the strata in actual conditions is simulated. The water tank section adjusts the water levels at both ends of the sand box, controlling the flow state of groundwater in the sand box by adjusting the relative height of the two water tanks. The piezometer section measures the water head pressure at different locations in the aquifer within the sand box, characterizing the flow field of the sand box during pumping experiments. The pumping well section consists of boreholes with different inclination angles, composed of a pump and filter pipe, depending on the experimental purpose. This is used to obtain the rate of water level change and the size of the drawdown cone within the aquifer during pumping experiments at different inclination angles, and to monitor the disturbance to the flow field in real time. By conducting sandbox pumping experiments, the flow state of groundwater within the sandbox is monitored and analyzed to obtain dynamic distribution data of the flow field. This data is then further expanded to the entire engineering area through scale transformation and spatial interpolation techniques, providing more accurate simulation results for hydrogeological analysis and engineering geological evaluation. This provides scientific and quantitative decision support for engineering hydrogeological risk assessment, groundwater resource management, and seepage prevention design. Attached Figure Description

[0023] Figure 1 This is a structural diagram of an experimental apparatus and method for simulating inclined borehole pumping experiments proposed in this invention.

[0024] Figure 2 This is a top view of an experimental apparatus and method for simulating inclined borehole pumping experiments proposed in this invention.

[0025] Figure 3 This is a three-dimensional diagram of an experimental apparatus and method for simulating inclined borehole pumping experiments proposed in this invention.

[0026] Figure 4This is a diagram of the two-layer structure of the permeable plate in this invention.

[0027] Figure 5 This is a uniform sand filling method with isotropic properties.

[0028] Figure 6 This is an anisotropic horizontal sand filling method.

[0029] Figure 7 It is an anisotropic inclined sand filling method. Detailed Implementation

[0030] Example 1

[0031] An experimental apparatus for simulating inclined borehole pumping experiments, such as Figure 1 As shown, the experimental setup includes a sand box section A, a water tank section B, a pressure measuring tube section C, and a water pump section D. The sand box section A includes a sand box baffle plate 1, a sand box permeable plate 2, a pressure measuring point 3, a vertical well 4, an inclined well 5, an isolation plate 6, and moving wheels 7. The water tank section B includes a left water tank B1 and a right water tank B2. The left water tank B1 includes a left water tank body 8, a left water tank height adjusting screw 9, and a left sand box inlet valve 10. The right water tank B2 is the same as the left water tank B1, including a right water tank body 11, a right water tank height adjusting screw 12, and a right sand box inlet valve 13. The pressure measuring tube section C includes a pressure measuring panel 14 and a pressure measuring tube 15. The water pump section D includes a vertical well pumping pipe 16, an inclined well pumping pipe 17, a water pump 18, and a water pump outlet pipe 19.

[0032] like Figure 2 , Figure 3 As shown, the left water tank body 8 includes a left water tank inlet 20, a left water tank sand box connecting pipe 21, a left overflow plate 22, and a left overflow outlet 23; the right water tank body 11 includes a right water tank inlet 24, a right water tank sand box connecting pipe 25, a right overflow plate 26, and a right overflow outlet 27; the water tank is connected to the water tank inlet via a water pipe to replenish the water tank, and the water tank is connected to the sand box via the water tank sand box connecting pipe. By controlling the sand box inlet valve, the sand box is filled with water. The water level in the water tank reaches the overflow plate and no longer rises. The overflowing water flows out from the overflow outlet, thereby controlling the water head in the water tank to remain constant.

[0033] like Figure 3 As shown, the height of the water tanks on the left and right sides is controlled by the height adjustment screw 9 of the left water tank and the height adjustment screw 12 of the right water tank. The screws are marked with scales. By adjusting the height of the water tanks on both sides, the distribution and change of the flow field in the sand box after pumping water under different conditions are simulated, and the flow field difference of the sand box in the vertical well pumping experiment and the inclined well pumping experiment are compared.

[0034] like Figure 4As shown, the sand box permeable plate 2 includes an acrylic perforated plate 28 and a mesh 29, wherein the mesh allows water to pass through but not sand, ensuring that the sand is sealed in the sand box, while water can enter the sand box through the sand box permeable plate 2.

[0035] Pressure measuring points 3 are evenly distributed on the front and back of the sand box, and pressure measuring tubes are connected to the measuring points. The water head values ​​at different depths and cross-sections in the sand box are obtained by reading the pressure measuring tubes, which can characterize the flow field distribution in the sand box. The pressure measuring tubes are connected in the following order: from top to bottom and from left to right. Figure 1 This is the connection method for the first column of pressure measuring points; after connection, the pressure measuring pipes connected to the pressure measuring points in the column of pressure measuring points in the pressure measuring panel are a group, each representing the water head on a cross section. The water head value of a certain plane in different groups from left to right can reflect the distribution of the flow field in the sand box; pressure measuring points are set along a straight line at the bottom of the sand box, one of which passes through the bottom of the pumping well and is used to determine the well water level. The pressure measuring pipes connected to the pressure measuring points at the bottom of the sand box are placed at the end of the pressure measuring panel.

[0036] The sand box is divided into two parts by a partition plate 6: a vertical shaft pumping sand box and an inclined shaft pumping sand box. Pressure measuring points are set on both sides of the vertical shaft and the inclined shaft and connected to pressure measuring pipes. The pressure pipe head can characterize the flow field and can be used to test the flow field distribution of the vertical shaft and the inclined shaft pumping experiment.

[0037] Different aquifer conditions can be simulated by changing the particle size and filling method of the sand sample in the sand box. Figure 5 The sand and gravel of the same particle size are evenly spread throughout the sand box to simulate the conditions of a homogeneous isotropic aquifer.

[0038] Figure 6 Different particle sizes of sand and gravel were layered and horizontally loaded into a sand box to simulate the conditions of horizontally distributed strong and weak interlayered aquifers.

[0039] Figure 7 Different particle sizes of sand and gravel were layered and tilted into a sand box to simulate the conditions of a non-horizontal aquifer.

[0040] Example 2

[0041] Conduct a simulated inclined borehole pumping experiment following these steps:

[0042] ①For example Figure 1 As shown, prepare the experimental setup. Connect the left water tank body 8 to the sand tank via the left water tank-sand tank connecting pipe 16; connect the right water tank body 11 to the sand tank via the right water tank-sand tank connecting pipe 25; connect the pressure measuring pipes at pressure measuring point 3 in a top-to-bottom and left-to-right order, as shown. Figure 1 This is the connection method for the first column of pressure test points. Connect all pressure test points in all columns in sequence according to this connection method.

[0043] ② After the apparatus is installed, sand of the required particle size is sieved through a sand sieve. The sand is then filled into the sand box on both sides of the isolation plate 6, ensuring compaction layer by layer. Different sand filling methods are required to simulate different aquifer conditions. This experiment uses three sand filling modes: uniformly spreading sand of the same particle size throughout the sand box to simulate homogeneous isotropic aquifer conditions; horizontally filling the sand box with layers of sand of different particle sizes to simulate horizontally distributed aquifer conditions with alternating strong and weak layers; and tilting the sand box with layers of sand of different particle sizes to simulate non-horizontal aquifer conditions. The sand sample is bounded by the permeable plate 2, the panel containing the pressure measuring point 3, and the isolation plate 6.

[0044] ③ After the sand sample is filled, adjust the height adjustment screws 9 and 12 of the left and right water tanks to make the main bodies 8 and 11 of the left and right water tanks at the same height. Open the water inlet valves 10 and 13 of the left and right sand tanks. The water tank supplies water to the main bodies 8 and 11 of the left and right water tanks through the water inlet 20 and 24 of the left and right water tanks, respectively. The water in the tanks is then supplied to the sand tanks through the connecting pipes 21 and 25 of the left and right water tanks. The sand box flows and, under the control of the acrylic perforated plate 28 and the mesh 29 of the permeable plate 2, fills the aquifer of the sand sample with water. When the water level on the left and right sides of the aquifer reaches the height of the overflow plate 22 on the left side and the overflow plate 26 on the right side, respectively, the water level on both sides stops rising. At this time, the water in the left and right sides overflows the overflow plate 22 on the left side and the overflow plate 26 on the right side and flows out from the overflow outlet 23 on the left side and the overflow outlet 27 on the right side, respectively, thus controlling the water level on both sides of the sand box to remain constant. The permeable plates 2 on the left and right sides are constant head boundaries, and the panel where the isolation plate 6 and the pressure measuring point 3 are located are water-proof boundaries.

[0045] ④ Use water pump 18 to pump water from the vertical shaft and the inclined shaft. Connect the power supply to the water pump, insert the vertical shaft pumping pipe 16 and the inclined shaft pumping pipe 17 into the vertical shaft and the inclined shaft respectively, set the water pumping flow rate, and start the water pump to pump water from the vertical shaft and the inclined shaft. The water in the vertical shaft and the inclined shaft is discharged through the water pump outlet pipe 19.

[0046] ⑤ Once the water levels in the vertical and inclined shafts have stabilized, observe the pressure measurement panel, record the pressure head data, and characterize the head lines and streamlines of the sand box based on the principle of interpolation. Analyze whether there are differences in the flow fields between the vertical and inclined shafts. If there are no differences, it indicates that the disturbance to the sand box flow field is consistent between the inclined and vertical shaft pumping experiments. In this case, the method for determining the aquifer permeability coefficient using the inclined shaft pumping test can be directly adopted. If there are differences, the correction method and correction coefficient for the inclined shaft pumping parameter determination can be derived by utilizing the difference in flow fields between the vertical and inclined shaft pumping tests. The correction method and correction coefficient may differ for different geological structures. This device is used to simulate different geological structures, and finally, the laboratory model is scaled up proportionally and applied to the engineering area to realize the parameter determination work of the inclined shaft pumping test in the project.

[0047] When discrepancies exist, this device corrects the parameters obtained from the vertical shaft pumping test to obtain accurate relevant parameters. For example, after filling with sand, the permeability coefficient of the sand sample is calculated using the vertical shaft pumping formula. Then, the permeability coefficient of the sand sample in the inclined shaft experiment is directly calculated using the vertical shaft parameter calculation method. Since different sand samples may have different (or no) differences, multiple experiments are needed to find the corresponding patterns. Using these patterns in conjunction with the vertical shaft parameter calculation, the final required parameters can be obtained. For example, when calculating parameters for a certain type of sand sample using the inclined shaft experiment, it is necessary to multiply the result by a certain factor after using the vertical shaft formula. However, the specific factor is unknown before the experiment. Through multiple experiments using this device, the corresponding factor pattern can be obtained. By multiplying the vertical shaft formula by this factor, the final parameters of the inclined shaft pumping test can be obtained.

[0048] ⑥ Stop pumping. When the sand box reaches its initial state again, adjust the pumping flow rate and start pumping. When the water level in the vertical shaft and the inclined shaft remains stable, observe the pressure measuring panel, record the pressure head data, and characterize the head lines and streamlines of the sand box according to the principle of interpolation. Analyze whether there are differences in the flow field between the vertical shaft and the inclined shaft.

[0049] ⑦ Adjust the left water tank height adjusting screw 9 to lower the left water tank height, causing the water level on the left side of the sand tank to drop. Once the water level stabilizes, repeat steps ④-⑥. Adjust the left water tank height adjusting screw 9 to restore the left water tank water level to be level with the right side. Adjust the right water tank height adjusting screw 11 to lower the right water tank height, causing the water level on the right side of the sand tank to drop. Repeat steps ④-⑥.

[0050] Considering the practical needs of hydrogeological engineering, the experimental device utilizes geological profile data obtained through geophysical exploration and drilling techniques. Based on the lithological characteristics of the strata, sand samples with different particle size distributions and permeability characteristics are filled into a sand box to achieve a proportionally scaled-down simulation of the strata in the engineering area. By controlling the particle size and combination of the filling material, irregular wedge-shaped impermeable materials are placed within the sand samples in the sand box to simulate the presence of impermeable layers in the actual geological structure, thus simulating the spatial distribution of strata in reality. Through sand box pumping experiments, the flow state of groundwater within the sand box is monitored and analyzed to obtain dynamic distribution data of the flow field. This data is further expanded to the entire engineering area through scale transformation and spatial interpolation techniques, providing relatively accurate simulation results for hydrogeological analysis and engineering geological evaluation. This provides scientific and quantitative decision support for engineering hydrogeological risk assessment, groundwater resource management, and seepage prevention design.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An experimental method for simulating an inclined borehole pumping experiment, based on an experimental device for simulating an inclined borehole pumping experiment, the experimental device comprising a sand box section A, a water tank section B, a pressure measuring pipe section C, and a pumping section D; the sand box section A includes a sand box baffle plate (1), a sand box permeable plate (2), a pressure measuring point (3), a vertical shaft (4), an inclined shaft (5), and an isolation plate (6), the sand box baffle plate (1) and the sand box permeable plate (2) being located at both ends of the sand box section A, and the vertical shaft (4) and the inclined shaft (5) being located in the middle of the sand box section A; the sand box section A is used to simulate an aquifer. By controlling the particle size and combination relationship of the filling material in the sand box section A, the actual spatial distribution of the strata is simulated; the water tank section B includes a left water tank B1 and a right water tank B2, and the left water tank B1 and the right water tank B2 are connected to the two sides of the sand box section A respectively; the left water tank B1 includes a left water tank body (8), a left water tank height adjustment screw (9), and a left sand box inlet valve (10), and the right water tank B2 includes a right water tank body (11), a right water tank height adjustment screw (12), and a right sand box inlet valve (13); through the water tank section Section B adjusts the water levels at both ends of the sand box, controlling the flow state of groundwater in the sand box by adjusting the relative height of the two water tanks; Section C is used to measure the magnitude of the water head pressure at different locations of the aquifer in the sand box, characterizing the flow field of the sand box in the pumping experiment; Section D includes a vertical shaft pumping pipe (16), an inclined shaft pumping pipe (17), a pumping pump (18), and a pumping pump outlet pipe (19); Section D is connected to the vertical shaft (4) through the vertical shaft pumping pipe (16) and to the inclined shaft (5) through the inclined shaft pumping pipe (17); Section D is used to adjust the water levels at both ends of the sand box according to different experimental purposes. A water pump and filter pipe are used to form boreholes with different inclination angles; sand samples with different particle size distributions and permeability characteristics are filled into a sand box according to the lithological characteristics of the strata, and the experimental device is used to achieve a scaled-down simulation of the strata in the engineering area; by obtaining the rate of change of water level and the size of the drawdown cone in the aquifer during pumping experiments in boreholes with different inclination angles, the disturbance of the flow field during the experiment can be monitored in real time; by conducting sand box pumping experiments, the flow state of groundwater in the sand box is monitored and analyzed, thereby obtaining dynamic distribution data of the flow field, and analyzing the differences and changes in the flow field distribution. Its characteristics are: The experimental method includes the following steps: ① Device installation The main body (8) of the left water tank is connected to the sand box through the left water tank sand box connecting pipe (16); the main body (11) of the right water tank is connected to the sand box through the right water tank sand box connecting pipe (25); the pressure measuring pipe (15) is connected at the pressure measuring point (3) in the order from top to bottom and from left to right, and arranged on the pressure measuring panel (14); ② Sand sample loading After the device is installed, the sand of the required particle size is sieved through a sand and gravel sieve. The sand is then filled into the sand box on both sides of the isolation plate (6). The sand is compacted layer by layer during filling. Different sand filling methods are required to simulate different aquifer conditions. This experiment uses three sand filling modes: uniformly spreading sand and gravel of the same particle size throughout the sand box to simulate homogeneous isotropic aquifer conditions; horizontally filling sand and gravel of different particle sizes into the sand box to simulate horizontally distributed strong and weak interlayered aquifer conditions; and tilting sand and gravel of different particle sizes into the sand box to simulate non-horizontal aquifer conditions. The sand sample is bounded by the permeable plate (2), the pressure measuring point (3) panel, and the isolation plate (6). ③ After the sand sample is filled, adjust the height adjustment screws (9) of the left water tank and (12) of the right water tank so that the main body (8) of the left water tank and the main body (11) of the right water tank are at the same height. Open the water inlet valve (10) of the left sand tank and the water inlet valve (13) of the right sand tank. The water tank supplies water to the main body (8) of the left water tank and the main body (11) of the right water tank through the water inlet (20) of the left water tank and the water inlet (24) of the right water tank. The water in the tank flows to the sand tank through the connecting pipe (21) of the left water tank and the connecting pipe (25) of the right water tank, and flows through the acrylic of the permeable plate (2). Under the control of the perforated plate (28) and the mesh (29), the sand sample aquifer is filled with water. When the water level on the left and right sides of the aquifer reaches the height of the overflow plate (22) on the left side and the overflow plate (26) on the right side respectively, the water level on the left and right sides no longer rises. At this time, the water in the left and right sides overflows the overflow plate (22) on the left side and the overflow plate (26) on the right side and flows out from the overflow outlet (23) on the left side and the overflow outlet (27) on the right side respectively, thereby controlling the water level on both sides of the sand box to remain constant. The permeable plates (2) on the left and right sides are the constant head boundary, and the panels where the isolation plate (6) and the pressure measuring point (3) are located are the water-proof boundary. ④ Use a water pump (18) to pump water from the vertical shaft and the inclined shaft. Connect the power supply to the water pump, insert the vertical shaft pumping pipe (16) and the inclined shaft pumping pipe (17) into the vertical shaft and the inclined shaft respectively, set the water pumping flow rate, and start the water pump to pump water from the vertical shaft and the inclined shaft. The water in the vertical shaft and the inclined shaft is discharged through the water pump outlet pipe (19). ⑤ Observe the pressure measuring panel (14) regularly and record the head size of the vertical shaft and the inclined shaft. Analyze the similarities and differences in the head change patterns of the vertical shaft and the inclined shaft during the pumping process. When the water level in the vertical shaft and the inclined shaft is stable, observe the pressure measuring panel, record the head data of the pressure measuring tube, and characterize the head lines and streamlines of the sand box according to the principle of interpolation. Analyze whether there are differences in the flow fields of the vertical shaft and the inclined shaft. If there are no differences, it means that the disturbance of the sand box flow field by the inclined shaft pumping experiment and the vertical shaft pumping experiment is consistent. In the actual project, the permeability coefficient of the aquifer can be obtained by directly using the vertical shaft pumping experiment parameter calculation method. If there are differences, the difference in the flow fields of the vertical shaft pumping experiment and the inclined shaft pumping experiment can be used to derive the correction method and correction coefficient for the inclined shaft pumping parameter calculation. The correction method and correction coefficient may differ for different geological structures. Use this device to simulate different geological structures and finally enlarge the laboratory model to the engineering area on a proportional scale to realize the parameter calculation work of the inclined shaft pumping experiment in the project. ⑥ Stop pumping. When the sand box reaches the initial state again, modify the pumping flow rate of the pump and start pumping. When the water level in the vertical shaft and the inclined shaft is stable, observe the pressure measuring panel (14), record the head data of the pressure measuring tube (15), and depict the head line and streamline of the sand box according to the principle of interpolation. Analyze whether there is a difference in the flow field between the vertical shaft and the inclined shaft. ⑦ Adjust the left water tank height adjustment screw (9) to lower the left water tank height, causing the water level on the left side of the sand tank to drop. After the water level stabilizes, repeat steps ④-⑥. Adjust the left water tank height adjustment screw (9) to restore the water level on the left water tank to be level with the right side. Adjust the right water tank height adjustment screw (11) to lower the right water tank height, causing the water level on the right side of the sand tank to drop. Repeat steps ④-⑥. Considering the actual needs of hydrogeological engineering, sand samples with different particle size distributions and permeability characteristics are filled into sand boxes according to the lithological characteristics of the strata. The experimental device is used to simulate the strata of the engineering area at a scaled-down ratio. By carrying out sand box pumping experiments, the flow state of groundwater in the sand box is monitored and analyzed, thereby obtaining dynamic distribution data of the flow field and analyzing the differences and changes in the flow field distribution.

2. The experimental method for simulating inclined borehole pumping as described in claim 1, characterized in that: The left water tank body (8) includes a left water tank inlet (20), a left water tank sand box connecting pipe (21), a left overflow plate (22), and a left overflow outlet (23). The left overflow plate (22) is located between the left water tank inlet (20) and the left overflow outlet (23). The left water tank body (8) is connected to the sand box part A through the left water tank sand box connecting pipe (21). The left water tank sand box connecting pipe (21) is equipped with a left sand box inlet valve (10). The right water tank body (11) includes a right water tank inlet (24), a right water tank sand box connecting pipe (25), a right overflow plate (26), and a right overflow outlet (27); the right overflow plate (26) is located between the right water tank inlet (24) and the right overflow outlet (27); the right water tank body (11) is connected to the sand box part A through the right water tank sand box connecting pipe (25); the right water tank sand box connecting pipe (25) is equipped with a right sand box inlet valve (13); The water tank is connected to the water tank inlet via a water pipe to replenish the water tank. The water tank is connected to the sand tank via a water tank sand tank connecting pipe. By controlling the sand tank inlet valve, the sand tank is filled with water. Once the water level in the water tank reaches the height of the overflow plate, it stops rising. The overflowing water flows out from the overflow outlet, thereby keeping the water head in the water tank constant.

3. The experimental method for simulating inclined borehole pumping as described in claim 1, characterized in that: The height of the water tanks on the left and right sides is controlled by the height adjustment screw (9) of the left water tank and the height adjustment screw (12) of the right water tank, which are marked with scales. Adjusting the height of the water tanks on both sides is used to simulate the distribution and change of the flow field in the sand tank after pumping water under different initial conditions, and then compare the flow field differences between the vertical well pumping experiment and the inclined well pumping experiment.

4. The experimental method for simulating inclined borehole pumping as described in claim 1, characterized in that: Sand box section A is equipped with sand box permeable plates (2) on both the left and right sides. The sand box permeable plate (2) includes an acrylic perforated plate (28) and a mesh (29). The mesh (29) allows water to pass through but not sand, which is used to ensure that the sand is sealed in the sand box, while water can enter the sand box through the sand box permeable plate (2). Water from the water tanks on the left and right sides enters the sand box section A through the left water tank sand box connecting pipe (21) and the right water tank sand box connecting pipe (25), and fills the sand sample in the sand box with water through the sand box permeable plate (2).

5. The experimental method for simulating inclined borehole pumping as described in claim 1, characterized in that: The pressure measuring tube section C includes a pressure measuring panel (14) and a pressure measuring tube (15). Multiple pressure measuring points (3) are provided on the front, back and bottom of the sand box. The pressure measuring points (3) are connected to the pressure measuring tubes (15) and arranged in an orderly manner in the pressure measuring panel (14). The head value of different pressure measuring points (3) is obtained by reading the pressure measuring tube data, and the flow field of the sand box in the pumping test is characterized.

6. The experimental method for simulating an inclined borehole pumping experiment as described in claim 5, characterized in that: The isolation plate (6) divides the sand box section A into two parts: the vertical shaft pumping sand box and the inclined shaft pumping sand box; read the water head value of the pressure measuring pipe (15) connected to the pressure measuring point of the sand box, obtain the flow field distribution of the vertical shaft and the inclined shaft pumping experiment, and use it to analyze the differences and changes in the flow field distribution of the vertical shaft pumping sand box and the inclined shaft pumping sand box.

7. The experimental method for simulating inclined borehole pumping as described in claim 1, characterized in that: The sand box section A also includes a moving wheel (7), which allows the sand box section A to move freely so that the distance between the experimental devices can be adjusted at any time to conduct experiments better.

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