A hydraulic tunnel long-term water flow simulated environment test device and test method

Abstract

The present invention discloses a long-term water-passing simulated environment test device and test method for a hydraulic tunnel. The test device includes a physical model test chamber, a water-passing circulation device, a model bidirectional pressurizing device, and a data acquisition system. The water-passing device includes a water supply tank, a water storage tank, a transparent glass tube, and a flow control valve; the water-passing circulation device includes a water pressure automatic control system and a circulation pump; the data acquisition system includes a stress-strain monitoring device, a non-metallic ultrasonic detector, a water pressure gauge, a flow meter, and other data acquisition instruments. The test method includes the production and installation of test specimens, the installation of data acquisition instruments, and the collection and processing of data. The implementation steps include the assembly of the water-passing device and the water-passing circulation device, the installation of the data acquisition system, and the collection, processing, and analysis of data. The present invention can simulate the water-passing changes in the tunnel during the operation period according to the long-term water-passing environment of the hydraulic tunnel, and then study the influence of long-term water-passing on the surrounding rock and lining structure of the hydraulic tunnel wall.

Description

Technical Field

[0001] The invention relates to the field of tunnel engineering, in particular to a test device and a test method for simulating the operating environment of a water diversion tunnel, which are suitable for studying the long-term stability and durability of surrounding rocks and lining structures of tunnel engineering under the action of a water environment. Background Art

[0002] In recent years, with the construction of a large number of water supply and distribution projects, the areas involved are becoming wider and wider, and the geological conditions faced are becoming more and more complex. When encountering areas with good geological conditions, the tunnel design will adopt a non-lining support form. When the surrounding rock stability is poor, targeted lining support is required. During the excavation of the tunnel, the rock mass unloads toward the air surface, the surrounding rock loosens and deforms, and many fine joints and cracks are generated inside it; in addition, the tunnel is flooded for a long time during the operation period, and the cracks provide a natural seepage channel for water seepage. In addition, the surrounding rock of the tunnel vault, arch bottom, and cave wall is eroded by water flow, and the hydrophilic minerals of the surrounding rock are continuously dissolved, and the bonding force between particles is weakened. Under the influence of different water flow velocities and flow rates, the erosion of the surrounding rock by water will be further aggravated. If the tunnel adopts reinforced concrete lining support, due to the uneven surface of the concrete spraying layer and the acidity and alkalinity of the groundwater, long-term water erosion will have different degrees of impact on the durability of the lining structure, leading to a series of tunnel stability problems.

[0003] At present, the main research methods for the effects of long-term water flow in tunnels on the stability of surrounding rocks and the durability of lining structures are numerical simulation and indoor tests. Numerical simulation has the advantages of fast solution speed, low cost, and comprehensive data monitoring, but the fluid-solid coupling is complex and difficult, and the calculation model needs to be simplified, which makes it difficult to restore the actual working conditions of the project, and the accuracy of the calculation results is not supported by relevant data. Indoor tests are aimed at studying the long-term stability of tunnel water flow, mainly focusing on rock creep and rock seepage creep. This method has several shortcomings: ① The creep servo system is expensive, the strain gauge requires high sensitivity, and the system is difficult to maintain in the later stage; ② In rock creep tests, long-term stable pressure is required. Affected by the working principle of the servo system, the fluctuation of the hydraulic system has a great influence on the accuracy of the test results; ③ In the process of rock seepage creep test, when the confining pressure is greater than the pore pressure, it is difficult for water to flow through the rock specimen, and it is difficult to simulate long-term seepage. Only low confining pressure and high pore pressure seepage creep tests can be achieved. In addition, indoor tests are mainly focused on the research of 50×100mm standard rock specimens, and there are few related studies on model tests; ④ It is difficult for rock block tests to consider stress boundary conditions and water flow conditions at the same time. Summary of the invention

[0004] The purpose of the present invention is to provide a simulation device and test method for simulating the operation environment of a tunnel, which can restore the internal operation environment of the tunnel and realize long-term water flow in the physical model of the tunnel. By collecting the longitudinal wave velocity of the physical model under the influence of different water flow durations, different water flow rates, and different acidity and alkalinity of groundwater, and microscopically analyzing the physical model specimens before and after water flow, the stability of the tunnel surrounding rock under long-term water flow conditions is analyzed from the perspective of wave velocity degradation, component loss, and the evolution law of microstructure.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A long-term water-flow test device for a simulated environment tunnel includes a physical model test chamber, a water-flow device, a bidirectional pressurizing device, a circulation device, and a data acquisition system. The water-flow device includes a water supply tank, a water storage tank, a transparent glass tube, a rubber sealing plug, and a flow control valve; the circulation device includes a circulation pump and a water pressure automatic control system; the data acquisition system includes a stress gauge, a strain gauge, a non-metallic ultrasonic detector, a pressure gauge, and a flow meter acquisition instrument.

[0007] Furthermore, according to the tunnel engineering excavation and lining design data, the tunnel physical model is prefabricated into a model specimen with bare rock without support or with lining, and the model is made according to the cross-sectional shape of the engineering tunnel. The lining in the model can be cast and formed with concrete of different grades according to the engineering setting. After the physical model is made, the lining is prefabricated according to the size of the model tunnel, and the stress and strain monitoring device is buried during the prefabrication process.

[0008] Furthermore, based on the engineering geological and hydrological data, the composition and acidity and alkalinity of the engineering groundwater are understood and tested, and a test water source matching the engineering groundwater is prepared.

[0009] Furthermore, the height of the water supply tank was set, and the surrounding rock physical model specimen was sealed and connected to the water tank through a transparent glass tube and a rubber plug. A flow meter and a pressure gauge were installed at both ends of the specimen. The water flow velocity in the transparent glass tube was calculated by the flow rate, and the water pressure at the inlet and outlet was directly read.

[0010] Furthermore, the water pressure automatic control system is equipped with a controller and an alarm device. When the pressure monitored by the pressure gauge exceeds the normal pressure range of the equipment, the alarm device sends an alarm signal, and the water pressure automatic control system and the circulation pump will automatically cut off power to ensure safe operation of the equipment.

[0011] Furthermore, a filter is installed at the connection between the water storage tank and the transparent glass tube to filter and collect the debris particles generated during the test. The water storage tank and the transparent glass tube are connected by threads for easy disassembly and cleaning.

[0012] Furthermore, the steel plate of the bidirectional pressurizing device is placed in close contact with the physical model test cavity, and the physical model specimen is pressurized to a set pressure through a hydraulic jack, and the pressure is continuously stabilized to simulate the ground stress field of the tunnel surrounding rock.

[0013] Furthermore, the water supply tank is filled with water, and the water pressure automatic control system realizes different water flow rates through the physical model test cavity through different pressures, simulating the working environment of the hydraulic tunnel during operation; the monitoring system monitors the stress, strain, longitudinal wave velocity, and water flow rate of the physical model test cavity with long-term water flow, and analyzes and studies the stability and durability of the physical model test cavity.

[0014] The present invention also provides a tunnel long-term water flow test device and test method, which are characterized by comprising the following test steps:

[0015] Step 1: Preparation of tunnel physical model, including:

[0016] According to the tunnel engineering excavation and lining design data, the physical model of the tunnel is prefabricated into a model specimen with no support bare rock or lining. According to the set scale ratio, the external dimensions of the model specimen, the size of the internal tunnel and lining, and the size of the transparent glass tube are determined.

[0017] Step 2: Install the model specimen, including:

[0018] The bottom of the bidirectional pressurizing device and the single side wall steel plate are fixed by fixing nuts, and the physical model test cavity is fixedly placed in the test bench of the bidirectional pressurizing device. When the test starts, a hydraulic jack is used to transfer force to the steel plate through the pressurizing piston and piston rod, and the horizontal and vertical loads required for the test are applied to the physical model test cavity to simulate the geostress field of the hydraulic tunnel.

[0019] Step 3: Install the water tank, including:

[0020] The water supply tank and water storage tank are set up at a fixed height and position, and are sealed in series through transparent glass tubes with rubber plugs to prevent water leakage under the operating water pressure of the equipment. A flow control valve is installed on the transparent glass tubes at the lower end of the water storage tank and the water supply tank to facilitate the control of the test process.

[0021] Step 4: Install the circulation equipment, including:

[0022] The water pressure automatic control system is connected in series between the water supply tank and the physical model test chamber through a transparent glass tube. The test water flow rate is controlled by adjusting the working pressure of the water pressure automatic control system. The circulation pump is connected in series between the water storage tank and the water supply tank through a transparent glass tube to achieve water reuse.

[0023] Step 5: Install the data acquisition system, including:

[0024] During the prefabrication process, a fixed surrounding rock stress and strain monitoring device is installed on the free surface inside the model. Two flow meters and a pressure gauge are installed at each end of the physical model test chamber, and the third pressure gauge is installed at the tail of the circulating pump. The flow meter is used to read the flow inside the physical model test chamber during the test, and the pressure gauge is used to monitor the equipment operating pressure during the test to ensure that the equipment operates under normal pressure.

[0025] Step 6: Apply pressure with a bidirectional pressure device, including:

[0026] The physical model test cavity is placed close to the steel plates on the side walls and top of the bidirectional pressurizing device. The steel plates are squeezed by hydraulic jacks to apply horizontal and vertical loads to the model. When the preset pressure is reached, the pressurizing is stopped. The steel plates are fixed and the pressure is stabilized by the pressurizing piston and piston rod to simulate the in-situ stress field of the engineering tunnel.

[0027] Step 7: Prepare the water source for the test, including:

[0028] According to the engineering geological and hydrological data, the composition and acidity and alkalinity of the engineering groundwater are tested, and a test water source matching the composition and acidity and alkalinity of the engineering groundwater is prepared.

[0029] Step 8: Test water cycle, including:

[0030] Fill the water supply tank with water, open the flow control valve, and let the water flow through the water pressure automatic control system (2). The pressure pump is controlled by the pressure automatic control instrument panel to adjust the different water flow rates required for the test to pass through the tunnel physical model specimen inside the physical model test chamber. Turn on the circulation pump to circulate water to the water supply tank, so as to achieve the effect of long-term water flow in the physical model test chamber to simulate its operating environment.

[0031] Step 9: Experimental data processing and analysis, including:

[0032] The stress, strain, water flow rate, model longitudinal wave velocity and other data of the model specimen recorded by the data acquisition system during the long-term water circulation process are processed by computer. At the same time, the entire test is basically visualized, and the water penetration and model surrounding rock cracking during the test process can be observed to obtain the long-term durability and stability evolution law of the model specimen for analysis and research.

[0033] Compared with the current research methods and solutions on the effects of long-term water flow in tunnels on the stability of surrounding rocks and the durability of lining structures, the beneficial effects of the present invention are:

[0034] (1) The test model can be prefabricated into a model specimen of bare rock without support or with lining according to the tunnel engineering excavation and lining design data, and the model can be made according to the cross-sectional shape of the engineering tunnel, and the lining structure can use raw materials with concrete grades matching the engineering;

[0035] (2) The water source used in the test can be the original project groundwater, or the project groundwater composition and acidity and alkalinity tests can be carried out based on the engineering geological and hydrological data, and the test water source matching the project groundwater composition can be prepared;

[0036] (3) Use a bidirectional pressure device to apply horizontal and vertical loads to the tunnel physical model to restore the ground stress field of the tunnel surrounding rock;

[0037] (4) The test equipment realizes the automation of the whole test process and safety monitoring through the water pressure automatic control system and circulation pump, and can achieve long-term water flow under different flow rate conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is an overall diagram of the test device of the present invention.

[0039] Figure 2 It is a cross-sectional view of the physical model of the tunnel of the present invention.

[0040] Figure 3a It is a schematic diagram of the internal structure of the pressure control integrated system in the present invention.

[0041] Figure 3b It is a cross-sectional view of the pressure control integrated system in the present invention.

[0042] Figure 4a It is a schematic diagram of a water tank in the present invention.

[0043] Figure 4b It is the internal cross-sectional view of the water tank in the present invention.

[0044] Figure 5 Schematic diagram of the bidirectional pressurizing device in the present invention

[0045] Among them, 1-physical model test chamber; 11-lining; 12-surrounding rock stress and strain monitoring device; 2-water pressure automatic control system; 21-pressure automatic control instrument panel; 22-pressure pump; 23-built-in water tank; 3-water storage tank; 31-filter screen; 32-water pipeline; 4-water supply tank; 41-transparent glass tube; 42-flow control valve; 5-circulation pump; 6-bidirectional pressurizing device; hydraulic jack-61; steel plate-62; pressurizing piston 63; piston rod-64; fixing nut-65; 7-flow meter; 8-pressure gauge; 9-non-metallic ultrasonic detector. DETAILED DESCRIPTION

[0046] The following is a further detailed description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. The embodiments described below are only a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] like Figure 1-5 As shown, a tunnel simulated environment long-term water flow test device of the present invention comprises a physical model test chamber 1, a water pressure automatic control system 2, a water storage tank 3, a water supply tank 4, a circulation pump 5; a two-way pressurizing device 6; a flow meter 7; a pressure gauge 8; and a non-metallic ultrasonic detector 9;

[0048] like Figure 2 As shown, linings 11 of different strength grades can be prefabricated inside the physical model test cavity 1, and surrounding rock stress and strain monitoring devices 12 are buried before prefabrication to monitor and collect surrounding rock stress and displacement data during the test.

[0049] Figure 3a , 3b As shown, the water pressure automatic control system 2 includes a pressure automatic control instrument panel 21, a pressure pump 22, and a built-in water tank 23. The water can be circulated under different flow rate conditions through the control of the automatic control instrument panel 21. The water pressure automatic control system 2 is equipped with a controller and an alarm device. When the pressure monitored by the pressure gauge exceeds the normal pressure range of the equipment, the alarm device sends an alarm signal, and the water pressure automatic control system and the circulation pump will automatically cut off the power to ensure the safe operation of the equipment.

[0050] Figure 4a , 4b As shown, the water storage tank 3 includes a filter screen 31, a drain pipe 32, and a flow control valve 42. The physical model debris generated during the test is filtered and collected through the filter screen 32. When the equipment operates abnormally, the flow control valve 42 can be opened to release water and pressure through the drain pipe 32 to ensure the safety of the equipment.

[0051] Figure 5 As shown, the bidirectional pressurizing device 6 includes a hydraulic jack 61, a steel plate 62, a pressurizing piston 63, a piston rod 64, and a fixing nut 65. The bottom and the single side wall steel plate 62 are fixed, and the bidirectional pressurizing device 6 is placed in the physical model test chamber 1. The hydraulic jack 61, the pressurizing piston 63, and the piston rod 64 transmit force to the steel plate 62 to apply the horizontal and vertical loads required for the test, simulating the ground stress field of the hydraulic tunnel.

[0052] A test method for a tunnel long-term water flow test device comprises the following test steps:

[0053] Step 1: Preparation of tunnel physical model, including:

[0054] According to the tunnel engineering excavation and lining design data, the tunnel physical model is selected to be prefabricated into a model specimen without support bare rock or with lining. According to the set scale ratio, the external dimensions of the model specimen, the dimensions of the internal tunnel and lining 11, and the dimensions of the transparent glass tube 41 are determined.

[0055] Step 2: Install the model specimen, including:

[0056] The bottom of the bidirectional pressurizing device 6 and the single side wall steel plate 62 are fixed by fixing nuts 65, and the physical model test chamber 1 is fixedly placed in the test bench of the bidirectional pressurizing device 6. When the test starts, the hydraulic jack 61 is used to transfer the force to the steel plate 62 through the pressurizing piston 63 and the piston rod 64, and the horizontal and vertical loads required for the test are applied to the physical model test chamber 1 to simulate the ground stress field of the hydraulic tunnel.

[0057] Step 3: Install the water tank, including:

[0058] The water supply tank 4 and the water storage tank 3 are set up at a fixed height and position, and are sealed in series through a transparent glass tube 41 using a rubber plug to prevent water leakage under the operating water pressure of the equipment. A flow control valve 42 is installed on each of the transparent glass tubes 41 at the lower ends of the water storage tank 3 and the water supply tank 4 to facilitate the control of the test process.

[0059] Step 4: Install the circulation equipment, including:

[0060] The water pressure automatic control system 2 is connected in series between the water supply tank 4 and the physical model test chamber 1 through a transparent glass tube 41, and the test water flow rate is controlled by adjusting the working pressure of the water pressure automatic control system 2. The circulation pump 5 is connected in series between the water storage tank 3 and the water supply tank 4 through a transparent glass tube 41 to achieve water reuse.

[0061] Step 5: Install the data acquisition system, including:

[0062] During the prefabrication of the lining 11, a fixed surrounding rock stress and strain monitoring device 12 is installed on the free surface inside the model. Two flow meters 7 and a pressure gauge 8 are installed at each end of the physical model test chamber 1, and the third pressure gauge is installed at the tail of the circulating pump. The flow meter 7 is used to read the flow inside the physical model test chamber 1 during the test, and the pressure gauge 8 is used to monitor the equipment operating pressure during the test to ensure that the equipment operates under normal pressure.

[0063] Step 6: Apply pressure with a bidirectional pressure device, including:

[0064] The physical model test chamber 1 is placed close to the steel plate 62 on the side wall and top of the bidirectional pressurizing device 6, and the steel plate 62 is squeezed by the hydraulic jack 61 to apply horizontal and vertical loads to the model. When the preset pressure is reached, the pressurizing is stopped, and the steel plate 62 is fixed and the pressure is stabilized by the pressurizing piston 63 and the piston rod 64 to simulate the in-situ stress field of the engineering tunnel.

[0065] Step 7: Prepare the water source for the test, including:

[0066] According to the engineering geological and hydrological data, the composition and acidity and alkalinity of the engineering groundwater are tested, and a test water source matching the composition and acidity and alkalinity of the engineering groundwater is prepared.

[0067] Step 8: Test water cycle, including:

[0068] Fill the water supply tank 4 with water, open the flow control valve 42, and the water flows through the water pressure automatic control system 2 to control the operation of the pressure pump 22 through the pressure automatic control instrument panel 21. The different water flow rates required for the test are adjusted to pass through the tunnel physical model specimen inside the physical model test chamber 1. Turn on the circulation pump 5 to circulate the water to the water supply tank 4, so as to achieve the effect of long-term water flow in the physical model test chamber 1 to simulate its operating environment.

[0069] Step 9: Experimental data processing and analysis, including:

[0070] The stress, strain, water flow rate, model longitudinal wave velocity and other data of the model specimen recorded by the data acquisition system during the long-term water circulation process are processed by computer. At the same time, the entire test is basically visualized, and the water penetration and model surrounding rock cracking during the test process can be observed to obtain the long-term durability and stability evolution law of the model specimen for analysis and research.

Claims

1. A hydraulic tunnel long-term water flow simulated environment test device, characterized in that: The invention comprises a physical model test chamber (1), a circulation device, a data acquisition system, a water storage tank (3), a water supply tank (4), a transparent glass tube (41), a flow control valve (42) and a bidirectional pressurizing device (6). The circulation device comprises a water pressure automatic control system (2) and a circulation pump (5). The data acquisition system comprises a surrounding rock stress and strain monitoring device (12), a flow meter (7), a pressure gauge (8) and a non-metallic ultrasonic detector (9). After the height of the water supply tank (4) is set up, the water pressure automatic control system (2) is placed below the water supply tank (4) and connected with the transparent glass tube (41). After the physical model test chamber (1) is fixed inside the bidirectional pressurizing device (6), it is placed behind the water pressure automatic control system (2) and connected with the transparent glass tube (41). 1) is connected to the water pressure automatic control system (2); after the installation is completed, a water storage tank (3), a circulation pump (5), and a water supply tank (4) are connected in sequence using a transparent glass tube (41); the circulation pump (5) is sealed and connected in series between the water storage tank (3) and the water supply tank (4); the flow control valve (42) is installed on the transparent glass tube (41) at the lower end of the water storage tank (3) and the water supply tank (4); the flow meter (7) and the pressure gauge (8) are installed at both ends of the physical model test chamber (1) and a pressure gauge (8) is installed at the end of the circulation pump (5) to read the water flow rate during the test and the internal operating pressure of the monitoring equipment. The interior of the test device is sealed and impermeable and a certain pressure is stabilized to ensure that water flows through the physical model test chamber (1) at a required flow rate to simulate the water flow environment inside the tunnel.

2. A hydraulic tunnel long-term water flow simulated environment test device according to claim 1, characterized in that: The tunnel physical model inside the physical model test chamber (1) is prefabricated into a model specimen of bare rock without support or containing lining according to tunnel engineering excavation and lining design data, and the model is manufactured according to the cross-sectional shape of the engineering tunnel. The external dimensions of the model specimen, the dimensions of the internal tunnel and lining (11), and the dimensions of the transparent glass tube (41) are prefabricated according to actual engineering and test requirements. During the process of prefabricating the lining (11), a fixed surrounding rock stress and strain monitoring device (12) is installed on the free surface inside the model.

3. A hydraulic tunnel long-term water flow simulated environment test device according to claim 1, characterized in that: The water pressure automatic control system (2) is equipped with a pressure automatic control instrument panel (21) and a pressure pump (22). The water pressure automatic control system (2) is equipped with an automatic control program to realize automatic control of different water pressures, different flow rates and the progress of the test during the test.

4. A hydraulic tunnel long-term water flow simulated environment test device according to claim 1, characterized in that: The water storage tank (3) is connected to a drain pipe and a valve. When the pressure gauge (8) of the test device shows that the internal pressure is abnormal, water is discharged and pressure is released through the drain pipe (32) and the flow control valve (42) at the bottom of the water storage tank (3).

5. According to the hydraulic tunnel long-term water flow simulated environment test device described in claim 4, a filter screen (31) is arranged inside the water tank to filter and collect debris generated in the physical model test chamber (1) during the test to ensure the safe operation of the test device.

6. A hydraulic tunnel long-term water flow simulated environment test device according to claim 1, characterized in that: The transparent glass tube (41) is connected in series with various components of the device by sealing using rubber stoppers.

7. A hydraulic tunnel long-term water flow simulated environment test device according to claim 1, characterized in that: The bidirectional pressurizing device (6) comprises a hydraulic jack (61), a steel plate (62), a pressurizing piston (63), a piston rod (64), and a fixing nut (65). The bottom of the bidirectional pressurizing device (6) and the single-side wall steel plate (62) are fixed by the fixing nut (65). The physical model test chamber (1) is placed in the bidirectional pressurizing device (6). The hydraulic jack (61) is used to transmit force to the steel plate (62) through the pressurizing piston (63) and the piston rod (64). The horizontal and vertical loads required for the test are applied to the physical model test chamber (1) to simulate the geostress field of a hydraulic tunnel.

8. The long-term water flow simulated environment test device for hydraulic tunnel according to claim 1 is characterized in that: The flow meter (7) and the pressure gauge (8) are installed at the connection points between the two ends of the physical model test chamber (1) and the transparent glass tube (41), respectively, to collect and safely monitor the water flow rate and water pressure of the physical model inside the physical model test chamber (1) in real time.

9. A hydraulic tunnel long-term water flow simulated environment test device according to claim 1, characterized in that: The non-metallic ultrasonic detector (9) collects longitudinal wave velocities at multiple points in real time on the physical model inside the physical model test cavity (1).

10. The test method of a hydraulic tunnel long-term water flow simulated environment test device according to any one of claims 1 to 8, comprising the following test steps: Step 1: Preparation of tunnel physical model, including: According to the tunnel engineering excavation and lining design data, the tunnel physical model is prefabricated into a model specimen with no support bare rock or with lining, and the external dimensions of the model specimen, the dimensions of the internal tunnel and lining (11) and the dimensions of the transparent glass tube (41) are determined according to the set scale ratio; Step 2: Install the model specimen, including: The bottom of the bidirectional pressurizing device (6) and the single side wall steel plate (62) are fixed by means of a fixing nut (65), and the physical model test chamber (1) is fixedly placed in the test bench of the bidirectional pressurizing device (6). When the test starts, a hydraulic jack (61) is used to transmit force to the steel plate (62) through a pressurizing piston (63) and a piston rod (64), and the horizontal and vertical loads required for the test are applied to the physical model test chamber (1), so as to simulate the geostress field of a hydraulic tunnel; Step 3: Install the water tank, including: The water supply tank (4) and the water storage tank (3) are installed at a fixed height and position, and are sealed in series through a transparent glass tube (41) using a rubber plug to prevent water leakage under the operating water pressure of the equipment, and a flow control valve (42) is installed at the lower end of the transparent glass tube (41) of the water storage tank (3) and the water supply tank (4) to facilitate the control of the test process; Step 4: Install the circulation equipment, including: The water pressure automatic control system (2) is connected in series between the water supply tank (4) and the physical model test chamber (1) through a transparent glass tube (41), and the test water flow rate is controlled by adjusting the working pressure of the water pressure automatic control system (2). The circulation pump (5) is connected in series between the water storage tank (3) and the water supply tank (4) through the transparent glass tube (41), so as to realize the reuse of water. Step 5: Install the data acquisition system, including: During the prefabrication of the lining (11), a fixed surrounding rock stress and strain monitoring device (12) is installed on the free surface inside the model, two flow meters (7) and a pressure gauge (8) are installed at each end of the physical model test chamber (1), and a third pressure gauge is installed at the tail of the circulating pump. The flow meter (7) is used to read the flow inside the physical model test chamber (1) during the test, and the pressure gauge (8) is used to monitor the operating pressure of the equipment during the test to ensure that the equipment operates under normal pressure; Step 6: Apply pressure with a bidirectional pressure device, including: The physical model test chamber (1) is placed in close contact with the steel plate (62) on the side wall and top of the bidirectional pressurizing device (6), and the steel plate (62) is squeezed by a hydraulic jack (61) to apply horizontal and vertical loads to the model. When a preset pressure is reached, the pressurizing is stopped, and the steel plate (62) is fixed and the pressure is stabilized by a pressurizing piston (63) and a piston rod (64), so as to simulate the in-situ stress field of the engineering tunnel; Step 7: Prepare the water source for the test, including: According to the engineering geological and hydrological data, the engineering groundwater composition and acidity and alkalinity tests are carried out, and the test water source matching the engineering groundwater composition and acidity and alkalinity is prepared; Step 8: Test water cycle, including: Fill the water supply tank (4) with water, open the flow control valve (42), and control the pressure pump (22) to operate through the water pressure automatic control system (2) and the pressure automatic control instrument panel (21). Adjust the different water flow rates required for the test to pass through the tunnel physical model specimen inside the physical model test chamber (1). Start the circulation pump (5) to circulate water to the water supply tank (4), so as to achieve the effect of long-term water flow through the physical model test chamber (1) to simulate its operating environment; Step 9: Experimental data processing and analysis, including: The stress, strain, water flow rate and model longitudinal wave velocity data of the model specimen recorded by the data acquisition system during the long-term water circulation process are post-processed by computer.

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