A simulation test device for screening water pressure load of a well wall structure and a method of using the same

Abstract

The application discloses a kind of simulation test devices of screen well wall structure water pressure load and its use method, it is related to mine construction engineering field.Can simulate the water pressure environment that well wall is suffered in screen well wall engineering in field under laboratory conditions, to determine the relationship between well wall outside water pressure distribution and each pipeline seepage flow in multiple working conditions;Meanwhile, a kind of method based on simulation test results deduces well wall outside water pressure distribution and each drainage pipeline flow relationship in field working condition is proposed.The simulation test device includes fan-shaped box, water storage tank, water pump and constant pressure device sequentially communicated to form loop.The simulation test device and its use method provided by the application can provide basic experimental research tool for the determination of screen well wall outside water pressure, to provide basic theoretical basis for screen well wall pressure relief hole design, and lay a foundation for the safe operation of deep vertical shaft well wall structure.

Description

Technical Field

[0001] This invention relates to the field of mining construction engineering. Background Technology

[0002] Coal, metals, and other mineral resources are mostly found in deep strata. As shallow resources are gradually depleted, the development of mineral resources towards deeper strata has become an inevitable trend. Deep shafts, as the vital passage to deep strata, are an important prerequisite for the exploitation of deep mineral resources. However, with the continuous increase in mining depth, the groundwater pressure on the shaft walls increases significantly, leading to a sharp increase in shaft wall thickness when designed according to current specifications, exceeding 8 meters in some projects.

[0003] The water pressure load on the outer side of the well wall structure is closely related to the amount of water flowing into the well from the surrounding rock. When there is no water inflow from the surrounding rock, the outer side of the well wall will bear the full hydrostatic pressure of the groundwater; however, as the amount of water flowing into the well from the surrounding rock increases, the water pressure load on the well wall will significantly decrease. Invention patent ZL201410471081.3, "A Well Wall Structure for a Mine Vertical Shaft Screen and Its Controllable Drainage Method," proposes a method of pre-burying drainage pipes behind the well wall during construction and actively draining water through connecting pipes to reduce the water pressure load on the well wall. This screen well wall structure, through the reasonable arrangement of drainage pipes, effectively reduces the water pressure on the outer side of the well wall by utilizing the active drainage effect within the pipes, while preventing the amount of water flowing into the well from the surrounding rock from exceeding the allowable value specified in the standard. This results in a reduction in the thickness of the well wall.

[0004] For the design of well screen wall structures, in order to accurately assess the impact of the drainage process on the water pressure on the well wall, it is necessary to clarify the quantitative relationship between the degree of water pressure reduction on the outside of the well wall (i.e., the ratio of the external water pressure to the original water pressure) and the drainage flow rate of the drainage pipe. However, at present, there is a lack of clear quantitative understanding of this relationship, which to some extent restricts the engineering application of well screen wall structures in high water pressure formations. Summary of the Invention

[0005] To address the above problems, this invention proposes a simulation test device and its method for testing the water pressure load on the well wall structure of a screen well. This device can simulate the water pressure environment experienced by the well wall in a field screen well project under laboratory conditions, thereby determining the relationship between the water pressure distribution on the outside of the well wall and the seepage flow of each pipe under various working conditions. At the same time, this invention proposes a method for extrapolating the relationship between the water pressure distribution on the outside of the well wall and the flow of each drainage pipe under field working conditions based on the simulation test results.

[0006] The technical solution of the present invention is as follows: the simulation test device includes a sector-shaped box 1, a water storage tank 11, a water pump 14 and a pressure regulating device 16 connected in sequence to form a loop;

[0007] One side of the fan-shaped box 1 is open, and a detachable panel 4 is installed on one side of the open side. Several outlet pipes 7 connected to the water storage tank 11 are installed on the other side, and a filter screen 6 is provided on one side of the outlet pipe 7. An inlet pipe 18 connected to the pressure regulating device 16 is fixedly installed on the detachable panel 4. A permeable support 3 is also provided in the fan-shaped box 1, and a rock and soil medium 2 is placed between the permeable support 3 and the filter screen 6.

[0008] The simulation test device also includes an external water pressure sensor 12 and an internal water pressure sensor 5. The external water pressure sensor 12 is located between the detachable panel 4 and the water-permeable support 3. There are multiple internal water pressure sensors 5, which are located on one side of the filter screen 6.

[0009] Each outlet pipe 7 is also equipped with an outlet pipe valve 8 and a flow meter 9.

[0010] Furthermore, the fan-shaped housing 1 is also provided with a side opening 19 for leading out the wires of the water pressure sensor 12 on the outside of the housing and the water pressure sensor 5 on the inside of the housing.

[0011] Furthermore, the pressure regulating device 16 is a device that provides a constant pressure water source. The pressure regulating device 16 is connected to the water pump 14 for water replenishment and pressure control, thereby applying a constant water pressure outside the rock and soil medium 2 to simulate the original water pressure of the surrounding rock.

[0012] Furthermore, the simulation test device also includes the data acquisition system, which is used to centrally collect the relevant electrical signals of the water pressure sensor 12 on the outside of the tank, the water pressure sensor 5 on the inside of the tank, and the flow meter 9, and save the converted specific water pressure, flow rate, and other results to the computer.

[0013] The method for using the simulation test device for water pressure load on the well wall structure of a sieve well is as follows:

[0014] Step 1: Setting up the experimental system;

[0015] Arrange the filter screen at the outlet pipe position inside the fan-shaped box. Arrange the water pressure sensor inside the box in an array. The arrangement of the water pressure sensor inside the box should cover the area where the outlet pipe is located. Then, lead the sensor wire out from the side opening of the fan-shaped box.

[0016] The soil and rock medium is filled into the fan-shaped box, and then the soil and rock medium is supported by a permeable baffle.

[0017] A water pressure sensor is placed on the outside of the fan-shaped box to test the water pressure at the inlet of the fan-shaped box. The sensor wire is led out from the side opening of the fan-shaped box.

[0018] Install the detachable panel on the outside of the fan-shaped box. The panel is bolted to the fan-shaped box, and a sealing ring needs to be installed on the contact surface between the panel and the fan-shaped box.

[0019] The pipeline connecting the inlet pipe of the sector-shaped box to the pressure regulating device, the pipeline connecting several outlet pipes of the sector-shaped box to the water storage tank, and the pipeline being equipped with a flow meter and valves; the pipeline connecting the water storage tank to the water pump, and the pipeline connecting the water pump to the pressure regulating device; the pipeline connecting the water pressure sensor wires, the data acquisition instrument and the computer to form a data acquisition system;

[0020] Step 2: Water pressure-discharge rate relationship test;

[0021] Open all valves on the connecting pipeline, and the sector-shaped box gradually fills with water under the action of the pressure regulating device. After passing through the soil and rock medium, the water flows out from the outlet pipe of the sector-shaped box. Turn on the water pump, and the water pump draws water from the water storage tank to replenish the pressure regulating device to control the pressure.

[0022] The discharge process in the experiment can be carried out in the form of single-hole pressure relief, double-hole pressure relief, and multi-hole pressure relief. The single-hole pressure relief mode refers to opening the valve on a single outlet pipe and closing the valves on the other outlet pipes. The double-hole pressure relief mode involves opening the valves on two adjacent outlet pipes as needed and closing the valves on the other outlet pipes. The multi-hole pressure relief mode involves opening the valves on multiple outlet pipes, and generally all the valves on the array outlet pipes can be opened.

[0023] During the test, opening the valve on the outlet pipe to different degrees can control the discharge flow rate. The water pressure inside and outside the sector box and the discharge flow rate of each outlet pipe are recorded by the data acquisition instrument.

[0024] Step 3: On-site engineering simulation;

[0025] Based on the water pressure data inside and outside the sector-shaped tank obtained in the experiment, the distribution of the water pressure reduction coefficient inside the tank is calculated. Specifically, the water pressure measured outside the tank is used as a reference value. The water pressure data inside the tank is divided by this reference value, and the resulting dimensionless water pressure is the water pressure reduction coefficient.

[0026] The experimental setup itself is a scaled-down model corresponding to the engineering site, with a geometric scaling ratio of λ. L That is, the ratio of the prototype size to the test model size; the cross-sectional area of ​​the drainage pipe on the inner side of the well wall corresponding to the engineering site is... , ,…., (Total N); In the experimental setup, the areas of the inner outlet pipes are s1, s2, ..., s NSince these areas in the engineering site and test apparatus are relatively small compared to the overall area, the field and test are approximately similar. If the permeability coefficient of the soil and rock material at the engineering site is k², then the scaling factor for the permeability coefficient is λ. k =k2 / k1;

[0027] The water pressure reduction factor in the engineering site is defined as the water pressure at each location outside the well wall divided by the in-situ water pressure of the distant formation. If the same water pressure reduction factor distribution is generated at the engineering site as in the experiment, the flow rate of each drainage pipe at the engineering site needs to be set to... , i =1,2,…, N.

[0028] The beneficial effects of this invention are as follows:

[0029] This invention provides a basic experimental setup and data conversion method for analyzing the water pressure load on the well wall structure of a screen well. Using this experimental setup, the relationship between the water pressure reduction coefficient distribution inside the fan-shaped box and the outlet pipe seepage flow combination under various modes such as single-hole, double-hole, and multi-hole can be obtained. It also provides a method for extrapolating engineering field scenarios based on the experimental results.

[0030] The simulation test device and its usage method proposed in this invention can provide a basic experimental research tool for determining the water pressure on the outside of the screen well wall, thereby providing a basic theoretical basis for the design of the pressure relief hole in the screen well wall and laying the foundation for the safe operation of the deep vertical well wall structure. Attached Figure Description

[0031] Figure 1 It is a test device system for water pressure load on the well wall structure of a sieve well;

[0032] Figure 2 It is a diagram of a sector-shaped box;

[0033] In the diagram: 1-fan-shaped box; 2-soil and rock medium; 3-permeable support; 4-removable panel; 5-water pressure sensor inside the box; 6-filter screen; 7-outlet pipe; 8-outlet pipe valve; 9-flow meter; 10-connecting pipe between the fan-shaped box and the water storage tank; 11-water storage tank; 12-water pressure sensor outside the box; 13-connecting pipe between the water storage tank and the water pump; 14-water pump; 15-connecting pipe between the water pump and the pressure regulating device; 16-pressure regulating device; 17-connecting pipe between the pressure regulating device and the fan-shaped water tank; 18-inlet pipe; 19-side opening. Detailed Implementation

[0034] To clearly illustrate the technical features of the present invention, the present invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0035] Deep shaft construction is of great significance for the development of coal, metals, and other mineral resources in my country. As shaft construction progresses deeper, the groundwater pressure on the shaft walls increases significantly, posing a severe challenge to the design of deep shaft wall structures. Screen shaft wall structures are a type of shaft wall structure that reduces water pressure on the outside of the shaft wall by pre-installing drainage pipes to actively divert groundwater. To conduct rational design of screen shaft wall structures, it is necessary to clarify the relationship between the water pressure on the shaft wall and the discharge flow rate of each drainage pipe during the drainage process; however, currently, there is a lack of relevant equipment and methods for determining this relationship.

[0036] This invention proposes a small-sized and simple scaled-down testing device and engineering data conversion method for novel screen well wall structures. The testing system has high controllability and repeatability for complex pressure relief and seepage processes in well walls, is applicable to different engineering scales and working conditions, and has good versatility. It provides a reliable basis for the engineering design and construction of screen well wall structures and helps to reduce the engineering risks related to screen well wall structures.

[0037] Specifically, such as Figure 1 , 2 As shown, it includes: a sector-shaped box 1, a pressure regulating device 16, a water pump 14, a soil and rock medium 2, a permeable baffle 3, a filter screen 6, water pressure sensors 5 and 12, a flow meter 9, a water storage tank 11, a data acquisition system, and connecting pipes 10, 13, 15, and 17.

[0038] The sector-shaped box 1 is a box with a horizontal cross-section in the shape of a sector and a certain height, which can be made of metal. The sector-shaped box 1 mainly holds the soil and rock medium 2 to simulate the surrounding rock within a certain influence range outside the well wall. The surrounding rock outside the well wall is originally a ring-shaped area; due to symmetry, a portion of the area, such as a sector-shaped area of ​​20˚~30˚, can be used to simulate this. This makes the test box 1 smaller, saving space and materials required for the experiment. During the experiment, the sector-shaped box 1 is placed horizontally, with the inner side of the soil and rock medium 2 corresponding to the outer side of the well wall, and the outer side of the soil and rock medium 2 being the boundary of the influence circle of the well wall's surrounding rock. The outer part of the sector-shaped box 1 is a detachable panel 4, which can be disassembled to fill with the soil and rock medium 2. The disassembled panel 4 is bolted to the box 1, and a sealing ring is provided at the connection point. A water inlet pipe 18 needs to be installed on the detachable panel 4, which is connected to a pressure regulating device 16 to provide a constant pressure water source. Several outlet pipes 7 are installed inside the fan-shaped box 1. The specific arrangement can be based on the actual situation of the drainage pipes in the well wall of the screen well, and can be arranged in rows and columns, such as... Figure 2 The enclosure is designed with 3 rows and 3 columns. An opening 19 needs to be provided on one side of the fan-shaped housing to allow the wires of water pressure sensors 5 and 12 to be routed out.

[0039] The pressure regulating device 16 is a device that provides a constant pressure water source by connecting the water inlet pipe 18 to the detachable panel 4 on the sector-shaped box 1. The pressure regulating device 16 can be a pressure tank, elevated water tank, etc., and needs to be connected to a water pump 14 for water replenishment and pressure control. The pressure regulating device 16 applies a constant water pressure to the outside of the rock and soil medium 2 in the sector-shaped box 1 to simulate the original water pressure of the surrounding rock.

[0040] The water pump 14 is mainly used to draw water from the water storage tank 11 and pump the water to the pressure regulating device 16 through the connecting pipe 13. If a pressure regulating tank is used, the start and stop of the water pump 14 are controlled according to the gas pressure in the pressure regulating tank. When the gas pressure is lower than the lower limit, water is added to the pressure regulating tank. When the gas pressure gradually rises to the upper limit, the water pump 14 stops.

[0041] The soil-rock medium 2 is a soil-rock mass filled in the sector-shaped box 1 to simulate the surrounding rock of the well wall. The soil-rock medium 2 does not need to be completely filled in the sector-shaped box 1; to prevent collapse, a permeable baffle 3 is used for support. The permeability coefficient k1 of the soil-rock medium 2 needs to be determined experimentally; this parameter is required when simulating the engineering site.

[0042] The permeable support plate 3 is placed inside the fan-shaped box 1 to support the soil and rock medium 2. Since the fan-shaped box 1 is placed horizontally, the soil and rock medium 2 may collapse, requiring the support plate for protection. The support plate 3 itself has good permeability, allowing water to pass through.

[0043] The filter screen 6 is installed at the outlet of each outlet pipe 7 inside the fan-shaped housing 1 for filtration. Water flow can carry soil particles 2 into the outlet, potentially causing blockage of the outlet pipe 7. The filter screen 6 serves to allow water to pass through while impeding particle flow, thus preventing blockage.

[0044] The water pressure sensors 5 and 12 are used to test the water pressure at representative locations within the sector-shaped housing 1. Water pressure sensor 12 is positioned on the outside of the soil and rock medium 2, and the measured value at this location represents the original water pressure. Water pressure sensor 5 is positioned on the inside of the soil and rock medium 2, and can be arranged in rows or columns. The arrangement range of water pressure sensor 5 needs to cover the area of ​​the outlet pipe 7 of the sector-shaped housing 1, such as in a 6-row, 6-column arrangement. Alternatively, it can be arranged at specific locations as needed.

[0045] The flow meter 9 is used to test the flow rate on the outlet pipe 7. A flow meter 9 needs to be installed on each outlet pipe 7 inside the sector housing 1. The flow meter 9 can test the actual water flow rate in the water pipe. A valve 8 needs to be installed on the flow meter 9 pipe. The water flow rate can be controlled by changing the opening degree of the valve 8.

[0046] The water storage tank 11 is a tank that collects the water flow from the outlet pipe 7 of the fan-shaped tank 1. The water in the water storage tank 11 also provides a water source for the subsequent pressure regulating device 16. The water pump 14 will draw water from the water storage tank 11 and replenish the pressure regulating device 16.

[0047] The data acquisition system is a system that centrally collects relevant electrical signals from water pressure sensors 5 and 12, flow meter 9, etc., and saves the converted results such as water pressure and flow rate to a computer. A common data acquisition system consists of a Datataker data acquisition instrument, a computer, etc.

[0048] The connecting pipes 10, 13, 15, and 17 mainly include pipe 10 connecting the water outlet pipe 7 of the sector-shaped housing 1 to the water storage tank 11, pipe 13 connecting the water storage tank 11 to the water pump 14, pipe 15 connecting the water pump 14 to the pressure regulating device 16, and pipe 17 connecting the pressure regulating device 16 to the sector-shaped housing 1. The connecting pipes can be metal pipes or heat-fused pipes.

[0049] A simulation test device for water pressure load on a well wall structure and its usage method are disclosed below:

[0050] Step 1: Setting up the experimental system;

[0051] A filter screen 6 is installed at the outlet pipe 7 inside the sector-shaped housing 1 to prevent water flow from carrying soil particles that could clog the outlet pipe 7. Water pressure sensors 5 are arranged in an array inside the sector-shaped housing 1, covering the area where the outlet pipe 7 is located. The sensor wires are then led out from the opening 19 on the side of the sector-shaped housing 1. Soil medium 2 is filled into the sector-shaped housing 1, and then supported by a permeable baffle 3 to prevent it from collapsing when the sector-shaped housing 1 is placed horizontally. A water pressure sensor 12 is installed on the outside of the sector-shaped housing 1 to test the water pressure at the inlet. The sensor wire is led out from the opening 19 on the side of the sector-shaped housing 1. A detachable panel 4 is installed on the outside of the sector-shaped housing 1. This panel 4 is bolted to the sector-shaped housing 1, and a sealing ring is installed on the contact surface between the panel 4 and the sector-shaped housing 1.

[0052] Pipe 17 connects the inlet pipe 18 of the sector-shaped housing 1 to the pressure regulating device 16; pipe 10 connects several outlet pipes 7 of the sector-shaped housing 1 to the water storage tank 11, and a flow meter 9 and a valve 8 are installed on this connecting pipe; pipe 13 connects the water storage tank 11 to the water pump 14, and pipe 15 connects the water pump 14 to the pressure regulating device 16. Water pressure sensors 5 and 12 are connected to wires, a data acquisition instrument, and a computer to form a data acquisition system.

[0053] Step 2: Water pressure-discharge rate relationship test;

[0054] Open all valves on the connecting pipeline. Under the action of the pressure regulating device 16, the sector-shaped box 1 gradually fills with water. After passing through the soil and rock medium 2, the water flows out from the outlet pipe 7 of the sector-shaped box 1. Turn on the water pump 14, which draws water from the water storage tank 11 to replenish the pressure regulating device 16, thereby controlling the pressure. The water storage tank 11 must be filled with sufficient water. The discharge process in the experiment can be carried out in the mode of single-hole pressure discharge, double-hole pressure discharge, and multi-hole pressure discharge. The single-hole pressure discharge mode refers to opening the valve 8 on a single outlet pipe 7 and closing the valves 8 on the other outlet pipes 7. The double-hole pressure discharge mode involves opening the valves 8 on two adjacent outlet pipes 7 as needed, while closing the valves 8 on the other outlet pipes 7. The multi-hole pressure discharge mode involves opening the valves 8 on multiple outlet pipes 7, and generally all the valves 8 on the array of outlet pipes 7 can be opened.

[0055] During the experiment, opening valve 8 on outlet pipe 7 to different degrees can control the discharge flow rate. The water pressure inside and outside the sector box 1 and the discharge flow rate data of each outlet pipe 7 are recorded by the data acquisition instrument.

[0056] Step 3: On-site engineering simulation;

[0057] Based on the water pressure data of the inside and outside of the sector-shaped tank 1 obtained in the experiment, the distribution of the water pressure reduction coefficient inside the tank is calculated. Specifically, the water pressure measured on the outside of the tank is used as a reference value. The water pressure data inside the tank is divided by this reference value, and the resulting dimensionless water pressure is the water pressure reduction coefficient.

[0058] The experimental setup itself is a scaled-down model corresponding to the engineering site, with a geometric scaling ratio of λ. L This refers to the ratio of the prototype size to the test model size. The cross-sectional area of ​​the drainage pipe inside the well wall corresponding to the engineering site is... , ,…., (Total N); In the experimental setup, the areas of the inner outlet pipe 7 are s1, s2, ..., s... N Since these areas in the engineering site and test setup are relatively small compared to the overall area, the field and test are approximately similar. If the permeability coefficient of the soil and rock material at the engineering site is k², then the scaling factor for the permeability coefficient is λ. k =k2 / k1.

[0059] The water pressure reduction factor in the engineering site is defined as the water pressure at each location outside the well wall divided by the in-situ water pressure of the distant formation. If the same water pressure reduction factor distribution is generated at the engineering site as in the experiment, the flow rate of each drainage pipe at the engineering site needs to be set as follows: , i =1,2,…,N.

[0060] There are many specific ways to implement this invention. The above description is only a preferred embodiment of this invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of this invention, and these improvements should also be considered within the scope of protection of this invention.

Claims

1. A simulation test device for water pressure load on a well wall structure, characterized in that, The simulation test device includes a sector-shaped box (1), a water storage tank (11), a water pump (14), and a pressure regulating device (16) that are connected in sequence to form a loop. The fan-shaped box (1) has an open side, with a detachable panel (4) installed on one side of the open side, and several outlet pipes (7) connected to the water storage tank (11) installed on the other side. A filter screen (6) is provided on one side of the outlet pipe (7). An inlet pipe (18) connected to the pressure regulating device (16) is fixedly installed on the detachable panel (4). A permeable support (3) is also provided in the fan-shaped box (1), and a soil medium (2) is placed between the permeable support (3) and the filter screen (6). The simulation test device also includes an external water pressure sensor (12) and an internal water pressure sensor (5). The external water pressure sensor (12) is located between the detachable panel (4) and the water-permeable support (3). There are multiple internal water pressure sensors (5), which are located on one side of the filter screen (6). Each outlet pipe (7) is also equipped with an outlet pipe valve (8) and a flow meter (9).

2. The simulation test device for water pressure load on a well wall structure according to claim 1, characterized in that, The fan-shaped box (1) is also provided with a side opening (19) for leading out the wires of the water pressure sensor (12) on the outside of the box and the water pressure sensor (5) on the inside of the box.

3. The simulation test device for water pressure load on a well wall structure according to claim 1, characterized in that, The pressure regulating device (16) is a device that provides a constant pressure water source. The pressure regulating device (16) is connected to a water pump (14) for water replenishment and pressure control, thereby applying a constant water pressure outside the rock and soil medium (2) to simulate the original water pressure of the surrounding rock.

4. The simulation test device for water pressure load on a well wall structure according to claim 1, characterized in that, The simulation test device also includes the data acquisition system, which is used to collect the relevant electrical signals of the water pressure sensor (12) on the outside of the box, the water pressure sensor (5) on the inside of the box, and the flow meter (9), and save the converted specific water pressure, flow rate and other results to the computer system.

5. A method of using the simulation test device for water pressure load on the well wall structure of a screen well as described in claim 1, characterized in that, Follow these steps: Step 1: Setting up the experimental system; Arrange the filter screen at the outlet pipe position inside the fan-shaped box. Arrange the water pressure sensor inside the box in an array. The arrangement of the water pressure sensor inside the box should cover the area where the outlet pipe is located. Then, lead the sensor wire out from the side opening of the fan-shaped box. The soil and rock medium is filled into the fan-shaped box, and then the soil and rock medium is supported by a permeable baffle. A water pressure sensor is placed on the outside of the fan-shaped box to test the water pressure at the inlet of the fan-shaped box. The sensor wire is led out from the side opening of the fan-shaped box. Install the detachable panel on the outside of the fan-shaped box. The panel is bolted to the fan-shaped box, and a sealing ring needs to be installed on the contact surface between the panel and the fan-shaped box. The pipeline connecting the inlet pipe of the sector-shaped box to the pressure regulating device, the pipeline connecting several outlet pipes of the sector-shaped box to the water storage tank, and the pipeline being equipped with a flow meter and valves; the pipeline connecting the water storage tank to the water pump, and the pipeline connecting the water pump to the pressure regulating device; the pipeline connecting the water pressure sensor wires, the data acquisition instrument and the computer to form a data acquisition system; Step 2: Water pressure-discharge rate relationship test; Open all valves on the connecting pipeline, and the sector-shaped box gradually fills with water under the action of the pressure regulating device. After passing through the soil and rock medium, the water flows out from the outlet pipe of the sector-shaped box. Turn on the water pump, and the water pump draws water from the water storage tank to replenish the pressure regulating device to control the pressure. The discharge process in the experiment can be carried out in the form of single-hole pressure relief, double-hole pressure relief, and multi-hole pressure relief. The single-hole pressure relief mode refers to opening the valve on a single outlet pipe and closing the valves on the other outlet pipes. The double-hole pressure relief mode involves opening the valves on two adjacent outlet pipes as needed and closing the valves on the other outlet pipes. The multi-hole pressure relief mode involves opening the valves on multiple outlet pipes, and generally all the valves on the array outlet pipes can be opened. During the test, opening the valve on the outlet pipe to different degrees can control the discharge flow rate. The water pressure inside and outside the sector box and the discharge flow rate of each outlet pipe are recorded by the data acquisition instrument. Step 3: On-site engineering simulation; Based on the water pressure data inside and outside the sector-shaped tank obtained in the experiment, the distribution of the water pressure reduction coefficient inside the tank is calculated. Specifically, the water pressure measured outside the tank is used as a reference value. The water pressure data inside the tank is divided by this reference value, and the resulting dimensionless water pressure is the water pressure reduction coefficient. The experimental setup itself is a scaled-down model corresponding to the engineering site, with a geometric scaling ratio of λ. L That is, the ratio of the prototype size to the test model size; the cross-sectional area of ​​the drainage pipe on the inner side of the well wall corresponding to the engineering site is... , ,…., (Total N); In the experimental setup, the areas of the inner outlet pipes are s1, s2, ..., s N Since these areas in the engineering site and test apparatus are relatively small compared to the overall area, the field and test are approximately similar. If the permeability coefficient of the soil and rock material at the engineering site is k², then the scaling factor for the permeability coefficient is λ. k =k2 / k1; The water pressure reduction factor in the engineering site is defined as the water pressure at each location outside the well wall divided by the in-situ water pressure of the distant formation. If the same water pressure reduction factor distribution is generated at the engineering site as in the experiment, the flow rate of each drainage pipe at the engineering site needs to be set to... , i =1,2,…, N.

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