Test method of model device for shield muddy water splitting centrifugal model test

Abstract

The invention discloses a test method of a model device for a shield muddy water splitting centrifugal model test, and particularly relates to the technical field of shield muddy water splitting tests. Comprising the following steps: preparing soil body slurry; solidifying the soil body slurry; preparing muddy water and injecting the muddy water into a muddy water tank, so that the muddy water enters the tunnel model through a high-pressure hose; pressurizing the interior of the muddy water tank until the soil body is split and damaged; muddy water is sprayed to the surface of the soil body, pressure is released to initial balance pressure, the pressure of an air pressure system is released in real time in the shutdown process, and the damage form after the excavation face is split is protected; after the machine is stopped, the cross shear test is carried out again immediately, then the soil body is excavated in a layered mode, and the fracture stretching form is observed and recorded; and finally cleaning the model box for next test. By the adoption of the technical scheme, the problem that a real stress field cannot be restored through a traditional 1g gravity model test is solved, and research on the shield excavation face muddy water splitting principle is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of shield mud water splitting test, in particular to a test method of a model device for a shield mud water splitting centrifugal model test. Background Art

[0002] At present, the research on shield slurry splitting test mainly focuses on triaxial splitting test and constant gravity model test. Under triaxial conditions, the actual stress conditions of the hollow cylindrical specimen and the soil in front of the shield excavation face are quite different, and the stress and seepage field of the specimen are relatively complex, and the importance and relationship of various factors in the test are difficult to distinguish. Therefore, it is very difficult to simulate the occurrence conditions and extension process of slurry splitting of the shield excavation face using triaxial tests, and its related results are difficult to apply to actual shield projects. In addition, small-scale model tests conducted in traditional 1g gravity model tests usually cannot reveal some important phenomena that may exist at the prototype stress level, especially for rock and soil materials, whose mechanical response depends on the effective stress level in the soil. For general undrained geotechnical engineering problems in clay, 1g gravity model tests can provide appropriate reducibility and reliable test results, but in the simulation of shield slurry splitting tests, 1g gravity model tests have the following limitations:

[0003] (1) The 1g gravity model test cannot restore the real geostress field. The magnitude of mud water pressure is an important factor that drives mud water cracks to extend to the surface. Its relative relationship with the geostress directly determines the extension of the crack tip. In addition, another important feature is that the in-situ stress changes with depth. The soil behavior is the result of the combined effect of stress level and stress history. Restoring these features in the physical model is crucial to the accuracy of the results. The 1g gravity model test cannot provide the in-situ level of stress, and coupled with the small size of the model, it may not be able to fully restore the real mud water splitting and extension phenomenon.

[0004] (2) It is difficult to ensure the similarity of soil and mud parameters in the 1g gravity model test. In general, the parameters of soil samples in the 1g model test are difficult to be completely similar to the actual ones. The similarity of parameters such as elastic modulus and cohesion can be ensured by controlling the sample preparation, but it is difficult to ensure the similarity of material properties such as sample density and Poisson's ratio. In the shield mud splitting model test, mud parameters are also involved. Its density, viscosity and other parameters are important factors affecting the stretching of mud. It is difficult to ensure the similarity of mud parameters and soil parameters in the 1g model test, which also brings certain errors to the 1g model test.

[0005] (3) The degree of consolidation of clay samples in the 1g gravity model test cannot be guaranteed. The strength properties of clay are very complex. Not only do they vary with different shear conditions, but they are also affected by factors such as the consolidation and drainage conditions of the soil, stress history, and soil anisotropy. Studies have shown that the degree of consolidation of clay has an important influence on the magnitude of the soil splitting pressure. In order to accelerate the consolidation of clay samples in the 1g model test, a prestress far greater than the stress generated in the test is often applied, which makes the clay samples in the test often over-consolidated soil, making it difficult to simulate normally consolidated clay samples. Summary of the invention

[0006] The present invention aims to provide a test method for a model device for a shield mud-water splitting centrifugal model test, which solves the problem that the traditional 1g gravity model test cannot restore the real stress field.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows: a test method for a model device for a shield mud-water splitting centrifugal model test, comprising the following steps:

[0008] S1. preparing soil slurry;

[0009] S2, consolidating the soil slurry in step S1, and placing a tunnel model and a micro earth pressure sensor in the consolidated soil, wherein the micro earth pressure sensor is arranged on the tunnel model;

[0010] S3, preparing muddy water and injecting the muddy water into a muddy water tank, so that the muddy water enters the tunnel model through a high-pressure hose;

[0011] S4. Start the centrifuge and observe the difference between the mud water pressure sensor and the lateral earth pressure value at the excavation face in real time during the acceleration stage. If the mud water pressure is insufficient, adjust the air pressure in time to ensure that the difference between the mud water pressure at the excavation face and the water and soil pressure in front fluctuates within a small range to ensure the initial balance of the excavation face.

[0012] S5. Pressurize the mud and water tank through the air pressure system, and conduct the test in a step-by-step pressurization manner until the soil is split and damaged;

[0013] S6. When the mud and water erupt to the soil surface, the pressure is released to the initial equilibrium pressure. During the shutdown process, the air pressure system is depressurized in real time to protect the damage form of the excavation surface after splitting. After the shutdown, the cross shear test is immediately carried out again, and then the soil is excavated in layers to observe and record the extension form of the cracks. Finally, the model box is cleaned and prepared for the next test.

[0014] Furthermore, the soil slurry is prepared as follows: degassed water is added to the dry kaolin powder until the water content is 1.5 times the liquid limit, and the slurry is stirred in a vacuum mixer in both forward and reverse directions for 3 hours each to achieve effective degassing and uniform mixing.

[0015] Furthermore, the method of step S2 is as follows:

[0016] S2.1. Soak the muddy water pressure sensor 24 hours in advance to remove the bubbles;

[0017] S2.2. Before transferring the soil slurry, apply vaseline on the inner wall of the model box, sprinkle a layer of sand on the bottom of the model box and cover it with a layer of geotextile;

[0018] S2.3. After weighing the model box, transfer the model box to the hanging basket of the centrifuge;

[0019] S2.4. Install a high-frequency data acquisition instrument electrically connected to the control system on the centrifuge, and electrically connect the high-frequency data acquisition instrument to each sensor, install a camera bracket on the model box, fix the high-speed camera through the camera bracket, debug the image and adjust the counterweight;

[0020] S2.5. Start the centrifuge and gradually accelerate to 100g. Allow the soil to consolidate for ten hours. During the consolidation process, observe the change of mud pressure through the mud pressure sensor, and use the Asaoka method to evaluate the average consolidation degree. After the consolidation is completed, turn off the centrifuge and immediately perform a cross shear test to measure the shear strength of the soil.

[0021] S2.6. After consolidation is completed, the model box is moved out and the water in the model box is drained. The model box is disassembled and a placement groove slightly larger than the tunnel model is cut out of the soil. The tunnel model is placed in the placement groove;

[0022] S2.7. Reassemble the model box, and after the soil is fully fitted to the side wall of the model box, add water to a specified height. At this point, the soil sample is complete.

[0023] Furthermore, in steps S2 and S3, degassed water is first poured in to cover the geotextile to a depth of about 5 cm. When transferring soil slurry or muddy water, the outflow port of the soil slurry or muddy water is immersed in water and then poured into the model box or muddy water tank to prevent bubbles from entering the soil sample or muddy water.

[0024] Furthermore, the mud water preparation method of step S3 is as follows: bentonite and water are mixed in a certain proportion, stirred in the forward and reverse directions for 1 hour each by an electric stirring rod, and then the viscosity of the mud water is measured by a Marsh funnel; and the mud water prepared in two test tubes is put into a small centrifuge for testing to ensure that the mud water will not separate under high centrifugal acceleration, and the rest is left standing for use.

[0025] Furthermore, the model device used in the test method includes a model box, a tunnel model is detachably connected to the model box, a micro pressure sensor is arranged in the tunnel model, an exhaust pipe is connected to the tunnel model, an exhaust valve is arranged on the exhaust pipe, the tunnel model is covered with soil located in the model box, a micro soil pressure sensor is arranged on the tunnel model, a high-pressure hose is connected to one side of the model box, a flow meter and a mud and water pressure sensor are arranged on the high-pressure hose, one end of the high-pressure hose is connected to a mud and water tank, an air intake pipe and an air pressure sensor located outside the air intake pipe are arranged on the mud and water tank.

[0026] Compared with the prior art, this solution has the following beneficial effects:

[0027] 1. This scheme uses the setting of structures such as the model box, mud water tank and tunnel model to enable the model box to accurately and quickly conduct centrifugal tests on shield mud water splitting, thereby effectively improving the effect of the shield mud water splitting centrifugal model test.

[0028] 2. In this scheme, the air pressure sensor can be used to accurately monitor the air pressure in the mud and water tank. At the same time, the exhaust pipe is set to facilitate the discharge of air inside the tunnel model to prevent the air inside the tunnel model from destroying the mud and water layer. At the same time, the high-transparency plexiglass window is set to enable image acquisition through a high-definition motion camera.

[0029] 3. This solution can realize the visualization of mud-water splitting phenomenon and real-time flow monitoring under high centrifugal acceleration conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the structure of the centrifuge in this embodiment;

[0031] Figure 2 is an axonometric view of the model device in this embodiment;

[0032] Figure 3 It is a front view of the model device in this embodiment;

[0033] Figure 4 yes Figure 3 Sectional view of AA in the middle;

[0034] Figure 5 It is a data graph collected by a test method of a model device for a shield mud-water splitting centrifugal model test of the present invention;

[0035] Figure 6 The invention discloses a splitting crack diagram obtained by testing a model device for a shield mud-water splitting centrifugal model test according to the present invention. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below through specific embodiments:

[0037] The figure marks in the drawings of the specification include: model box 1, tunnel model 2, exhaust pipe 3, exhaust valve 4, high-pressure hose 5, flow meter 6, mud water pressure sensor 7, mud water tank 8, fixing plug 9, air intake pipe 10, air pressure sensor 11, centrifuge 12, hanging basket 13.

[0038] Example

[0039] like Figures 1 to 4 As shown, a test method of a model device for a shield mud-water splitting centrifugal model test comprises the following steps:

[0040] S1. Prepare soil slurry. The preparation method of soil slurry is as follows: add degassed water to dry kaolin powder until the water content is 1.5 times of the liquid limit, that is, the weight ratio of kaolin powder to water is 1:1.2, and stir in a vacuum mixer in forward and reverse directions for 3 hours each to achieve effective degassing and uniform mixing.

[0041] S2, consolidating the soil slurry in step S1, placing the tunnel model 2 and the micro soil pressure sensor into the soil after consolidation, and setting the micro soil pressure sensor on the tunnel model 2. The method is as follows:

[0042] S2.1. Soak the mud water pressure sensor 24 hours in advance to expel the bubbles. Before the test, calibrate the micro soil pressure sensor and mud water pressure sensor. During the calibration, fix the micro soil pressure sensor and mud water pressure sensor to the bottom of the model box 1 with waterproof tape, add water to a certain height and start the centrifuge 12. Stabilize and record the data when accelerating to 20g, 40g, 60g, 80g and 100g, and finally obtain the calibration coefficient by drawing the relationship curve between the recorded data and the upper water pressure.

[0043] S2.2. Before transferring the soil slurry, the inner wall of the model box 1 is coated with vaseline to reduce the friction between the container wall and the soil. At the same time, to ensure smooth drainage during soil consolidation, a sand layer of about 2 cm is sprinkled on the bottom of the model box 1 and covered with a layer of geotextile. In order to prevent air entrapment, before pouring the soil slurry, degassed water is poured into the model box 1 to a depth of about 5 cm above the geotextile. When transferring the soil slurry, the outflow outlet of the soil slurry is immersed in water before pouring it into the model box 1 to prevent bubbles from entering the soil sample.

[0044] S2.3, after weighing the model box 1, transfer the model box 1 to the hanging basket 13 of the centrifuge 12 (the air pressure system and the mud water tank 8 also need to be transferred in this step). During the transfer process, the sensor circuit and the joint need to be protected. During the operation of the centrifuge 12, a large wind force will be generated in the centrifugal chamber. Therefore, after being transferred to the hanging basket 13, each circuit needs to be fixed to the rotating arm of the centrifuge 12 by a snap-fit ​​binding belt to prevent the circuit from being torn off under high centrifugal acceleration. The centrifuge 12 of this embodiment adopts the geotechnical centrifuge 12 of the National University of Singapore, and its main technical indicators are as follows:

[0045] (1) Centrifuge 12 capacity: 40 g·t;

[0046] (2) Maximum acceleration of centrifuge 12: 200g;

[0047] (3) Bucket design space: 0.75m (length) × 0.7m (width) × 1.2m (height);

[0048] (4) Centrifuge 12 radius: 1.2m;

[0049] (5) Effective load: 400kg maximum at 100g;

[0050] (6) The main machine adopts a single bucket and asymmetric arm structure.

[0051] S2.4. Install a high-frequency data acquisition instrument electrically connected to the control system of the centrifuge 12 on the centrifuge 12, and electrically connect the high-frequency data acquisition instrument to each sensor, install a triangular camera bracket on the outer wall of the model box 1 and fix the high-speed camera, debug the picture and adjust the counterweight.

[0052] S2.5. Start the centrifuge 12 and gradually accelerate it to 100g. Allow the soil to consolidate for ten hours. During the consolidation process, observe the change in mud pressure through a mud pressure sensor, and use the Asaoka method to evaluate the average consolidation degree. After consolidation is completed, turn off the centrifuge 12 and immediately conduct a cross shear test to measure the shear strength of the soil.

[0053] In this step, the Asaoka evaluation method is used: the height of the soil in the model box 1 is observed every hour during the test. When the settlement in n hours is equal to the settlement in n-1 hours, the consolidation is considered to be basically completed. The settlement obtained by intersecting the settlement curve with the 45° diagonal line passing through the origin is the final consolidation settlement. The average consolidation degree is the ratio of the measured settlement to the final consolidation settlement. Generally, when the average consolidation degree reaches 95%, the mud water pressure has basically remained stable.

[0054] S2.6. After consolidation is completed, the model box 1 is transferred out and the water in the model box 1 is drained. The plexiglass on the model box 1 is removed and a placement groove slightly larger than the tunnel model 2 is cut out of the soil and then placed into the tunnel model 2. At the same time, the line of the micro earth pressure sensor is led out from the side away from the tunnel to the side wall of the model box 1, and the model box 1 is fixed and fixed with waterproof tape.

[0055] S2.7. Reassemble the plexiglass of model box 1. After the soil and the side wall of the plexiglass are fully fitted together, add water to a specified height. At this time, the soil sample is completed.

[0056] S3, prepare muddy water and inject it into the muddy water tank 8. Before injecting the muddy water, pour degassed water to cover the geotextile to a depth of about 5 cm. When transferring the muddy water, immerse the outflow of the muddy water in water, and then pour it into the model box 1 or the muddy water tank 8 to prevent bubbles from entering the muddy water. Then open the exhaust valve 4 on the exhaust pipe 3, pour the prepared muddy water into the muddy water tank 8, and close the exhaust valve 4 after the muddy water level in the exhaust pipe 3 is stable. Among them, the muddy water preparation method is as follows: mix bentonite and water in a certain proportion, stir them in the forward and reverse directions for 1 hour each by an electric stirring rod, and then measure the viscosity of the muddy water by a Marsh funnel; and take the muddy water prepared in two test tubes and put them into a small centrifuge 12 for testing to ensure that the muddy water will not be separated under high centrifugal acceleration, and the rest is kept still for use.

[0057] S4, starting the centrifuge 12 through the control system of the centrifuge 12, and observing the difference between the mud water pressure sensor 7 and the lateral earth pressure value at the excavation surface in real time during the acceleration stage. If the mud water pressure is insufficient, timely adjust the air pressure to ensure that the difference between the mud water pressure at the excavation surface and the water and soil pressure in front fluctuates within a small range to ensure the initial balance of the excavation surface;

[0058] S5. Pressurize the mud and water tank 8 through the air intake pipe through the air pressure system, and use the step-by-step pressurization method (step-by-step pressurization every 12 seconds, with a gradient of 20kpa) to conduct the test until the soil is split and damaged; during the test, use a high-definition camera to record the entire process, and observe and record the soil damage during the pressurization process, as well as the changes in soil pressure and mud and water pressure in real time. The air pressure system mainly consists of a variable frequency compressor, an air filter and a pneumatic pressure regulating valve. The pneumatic pressure regulating valve is a high-precision pressure regulating valve of the Japanese SMC company model ITV1050-312L, which can achieve precise control of air pressure under high centrifugal acceleration. It is worth pointing out that when installing the air filter, the direction of the drain outlet at the bottom of the air filter should be consistent with the direction of the centrifugal force. Otherwise, once acceleration begins, the baffle near the drain valve is easy to fall off under the action of centrifugal force, causing leakage, causing the air compressor to overload. After the test air pressure control is correct, connect the high-pressure air pipe to the mud and water tank 8.

[0059] S6. When the mud and water erupt to the soil surface, the pressure is released to the initial equilibrium pressure. During the shutdown process, the air pressure system is depressurized in real time to protect the damage form of the excavation surface after splitting. After the shutdown, the cross shear test is immediately carried out again, and then the soil is excavated in layers to observe and record the extension form of the cracks. Finally, the model box 1 is cleaned up to prepare for the next test.

[0060] The model device used in the test method in this embodiment includes a model box 1, and a tunnel model 2 is detachably connected to the model box 1. In order to facilitate the observation of the extension morphology of the drowning crack, the model box 1 and the tunnel model 2 of this embodiment are composed of multiple pieces of organic glass. The cross section of the tunnel model 2 is D-shaped, and two fixing grooves are provided on the right side wall of the model box 1. The upper and lower ends of the tunnel model 2 are sealed and connected in the fixing grooves. A pressure sensor is provided in the tunnel model 2, and an exhaust pipe 3 is connected to the tunnel model 2. An exhaust valve 4 is provided on the exhaust pipe 3. With the help of the exhaust pipe 3 and the exhaust valve 4, the effective removal of air in the tunnel model 2 can be ensured to ensure the accuracy of the test results. The tunnel model 2 is covered with a soil body located in the model box 1, and a pore pressure sensor is provided in the soil body.

[0061] One side of the model box 1 is connected with a high-pressure hose 5, on which a flow meter 6 and a mud water pressure sensor 7 are arranged. The mud water pressure sensor 7 is arranged at the outlet of the mud water tank 8, and the height difference between its monitoring position and the center of the excavation surface of the tunnel model 2 is 90 cm. In this embodiment, the mud water pressure sensor 7 adopts a high-precision pressure transmitter with an accuracy of ±0.25% and a range of 0-1.5MPa. One end of the high-pressure hose 5 is connected with the mud water tank 8. In order to ensure that the slurry "does not seep, leak or burst" during the mud water pressurization process under high centrifugal acceleration, the mud water tank 8 needs to be tested with a water pressure test of 2 times the same pressure before the test to detect the sealing performance of the device. If water leakage is found, the mud water tank 8 needs to be sealed and welded again and tested repeatedly until the sealing performance reaches a stable state. A feeding port is opened at the top center of the mud water tank 8, and a fixing plug 9 is threadedly connected to the feeding port. The mud water tank 8 is provided with an air intake pipe 10 and an air pressure sensor 11 located on both sides of the fixing plug 9.

[0062] Figure 5 and 6 is the test result obtained by the test method of this embodiment, Figure 5 P1, P2, S1, S2, S3, and S4 are the pressure values ​​detected at different detection points in the tunnel model. It can be seen from the experiment that the limitations of the traditional 1g model test are overcome by the centrifuge test in this embodiment. The centrifuge model test can provide an equivalent high-magnetic acceleration field and can provide a real soil stress state in a small-scale model, so it is widely used in geotechnical engineering research. The effective stress and strength of the clay consolidated by the centrifuge test increase linearly with depth, which truly restores the typical normal consolidated clay on site.

[0063] The above are only embodiments of the present invention, and the common knowledge such as the known specific structures and / or characteristics in the scheme are not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A test method for a model device for a shield mud-water splitting centrifugal model test, characterized in that: The steps include: S1. preparing soil slurry; S2, consolidating the soil slurry in step S1, and placing a tunnel model and a micro earth pressure sensor in the consolidated soil, wherein the micro earth pressure sensor is arranged on the tunnel model; S3, preparing muddy water and injecting the muddy water into a muddy water tank, so that the muddy water enters the tunnel model through a high-pressure hose; S4. Start the centrifuge and observe the difference between the mud water pressure sensor and the lateral earth pressure value at the excavation face in real time during the acceleration stage. If the mud water pressure is insufficient, adjust the air pressure in time to ensure that the difference between the mud water pressure at the excavation face and the water and soil pressure in front fluctuates within a small range to ensure the initial balance of the excavation face. S5. Pressurize the mud and water tank through the air pressure system, and conduct the test in a step-by-step pressurization manner until the soil is split and damaged; S6. When the mud and water erupt to the soil surface, the pressure is released to the initial equilibrium pressure. During the shutdown process, the air pressure system is depressurized in real time to protect the damage form of the excavation surface after splitting. After the shutdown, the cross shear test is immediately carried out again, and then the soil is excavated in layers to observe and record the extension form of the cracks. Finally, the model box is cleaned and prepared for the next test.

2. The test method of a model device for shield mud water splitting centrifugal model test according to claim 1 is characterized by: The soil slurry was prepared as follows: degassed water was added to the dry kaolin powder until the water content was 1.5 times the liquid limit, and the slurry was stirred in a vacuum mixer in both forward and reverse directions for 3 hours each to achieve effective degassing and uniform mixing.

3. The test method of a model device for shield mud water splitting centrifugal model test according to claim 2 is characterized by: The method of step S2 is as follows: S2.

1. Soak the muddy water pressure sensor 24 hours in advance to remove the bubbles; S2.

2. Before transferring the soil slurry, apply vaseline on the inner wall of the model box, sprinkle a layer of sand on the bottom of the model box and cover it with a layer of geotextile; S2.

3. After weighing the model box, transfer the model box to the hanging basket of the centrifuge; S2.

4. Install a high-frequency data acquisition instrument electrically connected to the control system on the centrifuge, and electrically connect the high-frequency data acquisition instrument to each sensor, install a camera bracket on the model box, fix the high-speed camera through the camera bracket, debug the image and adjust the counterweight; S2.

5. Start the centrifuge and gradually accelerate to 100g. Allow the soil to consolidate for ten hours. During the consolidation process, observe the change of mud pressure through the mud pressure sensor, and use the Asaoka method to evaluate the average consolidation degree. After the consolidation is completed, turn off the centrifuge and immediately perform a cross shear test to measure the shear strength of the soil. S2.

6. After consolidation is completed, the model box is moved out and the water in the model box is drained. The model box is disassembled and a placement groove slightly larger than the tunnel model is cut out of the soil. The tunnel model is placed in the placement groove; S2.

7. Reassemble the model box, and after the soil is fully fitted to the side wall of the model box, add water to a specified height. At this point, the soil sample is complete.

4. The test method of a model device for shield mud water splitting centrifugal model test according to claim 3 is characterized by: In steps S2 and S3, first pour degassed water to cover the geotextile to a depth of about 5 cm. When transferring soil slurry or muddy water, immerse the outflow port of the soil slurry or muddy water in water and then pour it into the model box or muddy water tank to prevent bubbles from entering the soil sample or muddy water.

5. The test method of a model device for shield mud water splitting centrifugal model test according to claim 1 is characterized by: The mud water preparation method of step S3 is as follows: bentonite and water are mixed in a certain proportion, stirred in the forward and reverse directions for 1 hour each by an electric stirring rod, and then the viscosity of the mud water is measured by a Marsh funnel; and the mud water prepared in two test tubes is put into a small centrifuge for testing to ensure that the mud water will not separate under high centrifugal acceleration, and the rest is left standing for use.

6. A test method for a model device for shield mud-water splitting centrifugal model test according to any one of claims 1 to 5, characterized in that: The model device adopted by the test method includes a model box, a tunnel model is detachably connected to the model box, a micro pressure sensor is arranged in the tunnel model, an exhaust pipe is connected to the tunnel model, an exhaust valve is arranged on the exhaust pipe, the tunnel model is covered with soil located in the model box, a micro soil pressure sensor is arranged on the tunnel model, a high-pressure hose is connected to one side of the model box, a flow meter and a mud and water pressure sensor are arranged on the high-pressure hose, one end of the high-pressure hose is connected to a mud and water tank, an air intake pipe and an air pressure sensor located outside the air intake pipe are arranged on the mud and water tank.

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