A dynamic scale model and test method of the waterproof system at the tail of a shield machine

Abstract

The present invention belongs to the field of urban rail shield construction, and relates to a dynamic scale model of a shield machine tail waterproofing system. The present invention comprises an inner tube and an outer tube, wherein an inner bracket is fixed in the inner tube, and the inner bracket is fixed on a steerable and movable telescopic vehicle, and the inner tube is located in the outer tube, and the tail is closed; a disposable inner wall plate is fixed on the outer tube body, a shield tail brush is welded on the inner wall plate, an outer tube rear cover is installed at the tail of the outer tube, and a sealing gasket is installed in the outer tube rear cover. The present invention can simulate the excavation state of the shield machine during actual construction. The test device can test the waterproofing effect of different greases and different shield tail brushes under different shield tail gaps. The use of disposable inner wall plates increases the speed and simplicity of the test, and can test the sealing effect of the sealing system composed of different types of grease and different shield tail brushes under different water pressures and different shield tail gaps. At the same time, the scalability of the model provides more accurate data support for actual engineering.

Description

Technical Field

[0001] The present invention belongs to the field of urban rail shield construction and relates to a shield machine tail waterproofing system, specifically to a dynamic scaled model of the shield machine tail waterproofing system. The present invention also includes a test method and application of the dynamic scaled model. Background Art

[0002] With the rapid development of urban rail transit, the trend toward larger diameters and greater depths has placed higher demands on shield construction technology, particularly the waterproofing performance of the shield machine's tail section. Therefore, there is an urgent need to design a dynamic test device that can accurately simulate the actual tunneling state of the shield machine. This device can accurately simulate the dynamic changes in the shield tail brush and tunnel segments during tunneling, as well as the sealing performance of various parts of the tail waterproofing system, such as the shield tail brush and grease chamber, under external water and soil loads. This data will provide support for improvements to shield tail waterproofing and emergency response measures.

[0003] Currently, most existing shield tail waterproofing devices are static devices, with a fixed gap between the segments and the tail brush, and their sealing and waterproofing performance is often flawed. Invention Publication No. CN111720131A discloses a method and construction device for using a shield to break through a reinforced concrete portal. The construction device includes a sealing sleeve, which is composed of several sections, each section comprising an upper half-ring sleeve and a lower half-ring sleeve; a shield body mounted within the sealing sleeve, with a sealing device connected to the rear end of the sealing sleeve, and a sealing ring mounted at the front end of the sealing sleeve, with one end of the outer ring of the sealing ring mounted within the sealing sleeve and the other end affixed to the inner ring wall of the portal steel ring; a driving device connected to the inner wall of the sealing sleeve for driving the shield body forward and backward; a supporting device, which includes a transverse support and an oblique support, with the transverse support disposed at the bottom of the sealing sleeve and the oblique support mounted at the rear end of the sealing sleeve; and a tightening device, which is disposed between the oblique support and the sealing device.

[0004] During the actual operation of a shield machine, the shield tail brush and the tunnel segments fit together and move relative to each other. Furthermore, as the shield machine's excavation posture changes, the gap between the tunnel segments and the shield tail brush also changes continuously. Therefore, there is a large error between the shield tail waterproofing performance measured under static conditions and the actual working state. In order to measure the shield tail waterproofing performance closer to the actual excavation state, it is necessary to develop a dynamic scaled model of the shield machine tail waterproofing system. Summary of the Invention

[0005] The purpose of the present invention is to provide a dynamic scale model of a shield machine tail waterproofing system and a test method thereof, which solves the problem of low accuracy of the dynamic test device of the shield tail waterproofing in the prior art.

[0006] The present invention provides a dynamic scale model of the waterproof system at the tail of a shield machine, including an inner bracket. The dynamic scale model of the waterproof system at the tail of a shield machine includes a traction device, an inner tube 8 and an outer tube 9. The inner tube 8 and the outer tube 9 are hollow inside, and the outer diameter of the inner tube 8 is smaller than the inner diameter of the outer tube 9. The traction device is fixedly connected to the inner bracket, and the inner bracket is externally connected to the inner tube 8 and fixedly connected to the inner tube 8. The inner bracket includes a long rod inner bracket 5, a vertical rod inner bracket 6, and a horizontal rod inner bracket 7. The inner tube 8 is contained in the outer tube 9, and the tail is sealed. A grease cavity is set between the inner tube 8 and the outer tube 9, and the grease cavity is provided at the upper and lower parts. A grease injection hole 14 is provided, and a flat film pressure sensor 16 is provided on each side. The outer wall of the inner cylinder 8 contacts the shield tail brush 15; the shield tail brush 15 is fixedly connected to the inner wall plate of the outer cylinder 9, and forms a sealing and waterproof system with the grease 13; the inner wall plate is fixedly connected to the outer cylinder 9; the lower part of the outer cylinder 9 is installed with a directional wheel II (11), and the tail is sealed by the outer cylinder rotating rear cover 17; the inner bottom plate of the outer cylinder rotating rear cover 17 is installed with a sealing gasket 18, a water pressure sensor 19 and a water injection hole 20.

[0007] Preferably, the traction device is a power tractor, which includes a U-shaped bolt 1, a lifting bracket 2 in the height direction, a rotating disc 3 rotating on the xy plane, and a directional wheel 14 moving horizontally on the ground; the long rod inner bracket 5 is fixedly installed on the power tractor through the U-shaped bolt 1, the U-shaped bolt 1 is fixed to the upper cover plate of the lifting bracket 2, the lifting bracket 2 is connected to the rotating disc 3 at the bottom, and the rotating disc is connected to the directional wheel 14 at the bottom.

[0008] Preferably, the inner tube movable rod includes a long rod inner bracket 5 in the length direction, a horizontal rod inner bracket 7 in the width direction, and a vertical rod inner bracket 6 in the height direction; the plane formed by the vertical rod inner bracket 6 and the horizontal rod inner bracket 7 is arranged perpendicular to the long rod inner bracket 5; the end points of the horizontal rod inner bracket 7 and the vertical rod inner bracket 6 are fixed on the inner wall of the inner tube 8.

[0009] Preferably, the inner wall plate is a disposable inner wall plate 12, and the shield tail is a disposable shield tail; or the fixed connection is fixed by bolts or welding.

[0010] Preferably, the outer cylinder 9 includes a shield tail; the shield tail includes a disposable inner wall plate 12, fixing bolt holes 10 on both sides of the circumference, and a shield tail brush 15 fixed on the inner wall plate; the shield tail brush 15 contacts the outer wall of the inner cylinder 8 and is fixedly connected to the inner plate of the disposable inner wall plate 12.

[0011] Preferably, the shield tail brush 15 is welded to the inner plate of the disposable inner wall plate 12, forming a circle and overlapping each other to isolate the liquid; one or more shield tail brushes 15 are arranged between the inner tube 8 and the outer tube 9, and the one or more shield tail brushes 15 are all located between the two ends of the inner tube 8 and in the gap between the outer wall of the inner tube 8 and the inner plate of the disposable inner wall plate 12.

[0012] Preferably, the sealed rear cover includes an outer cylinder rotating rear cover 17 , a sealing gasket 18 , a water pressure sensor 19 , and a water injection hole 20 ; the sealing gasket 18 is placed in the outer cylinder rear cover 17 , and the outer cylinder rear cover 17 is rotatably fixed on the outer cylinder 9 .

[0013] The present invention provides a method for preparing a dynamic scaled model of the shield machine tail waterproofing system, comprising:

[0014] S1: Assemble the tractor by assembling the U-bolt 1, lifting bracket 2, rotating disc 3, and directional wheel I4 in order from top to bottom;

[0015] S2: Assemble the disposable shield tail and weld the shield tail brush 15 to the inner plate of the disposable inner wall plate 12 to form a circle and overlap each other; place the assembled disposable inner wall plate 12 into the outer cylinder 9 and fix it to the outer cylinder 9 through the bolt holes 10;

[0016] S3: Assemble the movable inner cylinder by overlapping the long rod inner bracket 5, the horizontal rod inner bracket 7, and the vertical rod inner bracket 6 in the length, width, and height directions. The end points of the horizontal rod inner bracket 7 and the vertical rod inner bracket 6 are fixed to the inner wall of the inner cylinder 8. At the same time, two grease injection holes 14 are provided at corresponding positions above and below the grease chamber, and two flat film pressure sensors 16 are provided at corresponding positions on the left and right. The exposed end of the long rod is fixed to the tractor with a U-bolt 1.

[0017] S4: Install the sealing gasket 18 into the outer cylinder rear cover 17, and rotate the outer cylinder rear cover 17 to fix it on the outer cylinder 9. At the same time, install the water pressure sensor 19 and the water injection pipe 20 on the outer cylinder rear cover 17.

[0018] The dynamic scaled model of the shield machine tail waterproofing system of the present invention can be used to simulate the tunneling of the shield machine. The specific method includes:

[0019] a. Start the traction device of the power tractor and slowly feed the inner cylinder 8 into the opening of the outer cylinder 9 until the inner cylinder 8 reaches the position of the first shield tail brush 15;

[0020] b. Start the grease pump and inject grease into the grease cavity between the inner cylinder 8 and the outer cylinder 9 through the grease injection hole 14. Observe the oil pressure of the flat membrane pressure sensor 16. After the grease cavity is filled, maintain a stable oil pressure. At the same time, start the water pump and set a fixed water pressure to inject water or muddy water into the outer cylinder 9 through the water injection hole 20. Observe the pressure of the water pressure sensor 19 and control the input pressure in real time.

[0021] c. Start the traction device to simulate the excavation behavior of the shield machine, observe the pressure changes of the flat membrane pressure sensor 16 and the water pressure sensor 19, and observe the water flow breakdown at the opening of the outer tube 9, record the data in time, and analyze and guide the engineering construction.

[0022] Preferably, the uniform forward movement of the tractor simulates the excavation of the shield machine; the dynamic scale model of the shield machine tail waterproofing system is proportionally reduced according to the actual shield machine, so as to obtain corresponding data through multiple tests and adjust the shield machine tail waterproofing system according to the experimental data.

[0023] The present invention can also use the control system to preset the traction device, such as the movement direction and speed of the tractor, so as to better simulate the tunneling situation of the shield machine.

[0024] In one embodiment of the present invention, a test method for a dynamic scaled model of a shield machine tail waterproofing system is provided, including a method for constructing and applying a dynamic scaled model of a shield machine tail waterproofing system, specifically comprising the following steps:

[0025] S1: Assemble the tractor. Assemble the U-bolt, lifting bracket, rotating disc, and directional wheel I in order from top to bottom.

[0026] S2: Assemble the disposable shield tail, weld the shield tail brush to the inner plate of the disposable inner wall plate, form a circle, overlap each other, put the assembled disposable inner wall plate into the outer cylinder, and firmly fix it on the outer cylinder through the bolt holes.

[0027] S3: Assemble the movable inner cylinder, overlap the long rod inner bracket, the horizontal rod inner bracket, and the vertical rod inner bracket according to the length, width and height, and weld the end points to the inner cylinder. At the same time, install the upper and lower grease injection holes corresponding to the grease chamber, as well as two flat film pressure sensors on the left and right sides. Fix the exposed end of the long rod to the tractor with a U-shaped bolt.

[0028] S4: Install the sealing gasket into the rear cover of the outer cylinder, and rotate the rear cover of the outer cylinder to fix it on the outer cylinder. At the same time, install the water pressure sensor and the water injection pipe on the rear cover of the outer cylinder.

[0029] S5: Start the traction device on the head and slowly push the inner tube into the opening of the outer tube until the inner tube reaches the position of the first shield tail brush.

[0030] S6: Start the grease pump and inject grease through the grease injection hole. Observe the oil pressure of the flat membrane pressure sensor. Maintain a stable oil pressure after the grease cavity is filled. At the same time, start the water pump and set a fixed water pressure to inject water or muddy water into the outer cylinder through the water injection hole. Observe the water pressure of the water pressure sensor and control the input pressure in real time.

[0031] S7: Start the traction device to simulate the excavation behavior of the shield machine, observe the pressure changes of the flat membrane pressure sensor and the water pressure sensor, and observe the water flow breakdown at the opening of the outer tube, record the data in time, and analyze and guide the construction of the project.

[0032] The present invention can simulate the actual excavation posture of the shield machine to a large extent, avoid opening holes in the outer cylinder to ensure waterproof performance, and at the same time improve the convenience and accuracy of the test. It can test the sealing effect of the sealing system composed of different types of grease and different shield tail brushes under different water pressures and different shield tail gaps, and can provide richer simulation working conditions and more accurate data support for shield construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, each drawing described below is for some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0034] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0035] Figure 2 Schematic diagram of the tractor structure.

[0036] Figure 3 Schematic diagram of the inner bracket structure.

[0037] Figure 4 This is the plan layout of the inner cylinder sensor.

[0038] Figure 5 This is a diagram of a disposable inner wall panel and a rotating rear cover.

[0039] Among them, the figures are marked as 1-U-shaped bolt, 2-lifting bracket, 3-rotating disc, 4-directional wheel I, 5-long rod inner bracket, 6-vertical rod inner bracket, 7-horizontal rod inner bracket, 8-inner cylinder, 9-outer cylinder, 10-bolt hole, 11-directional wheel II, 12-disposable inner wall plate, 13-grease, 14-grease injection hole, 15-shield tail brush, 16-flat membrane sensor, 17-outer cylinder back cover, 18-sealing gasket, 19-water pressure sensor, 20-water injection hole. DETAILED DESCRIPTION

[0040] The present invention discloses a dynamic scale model of a shield machine tail waterproofing system and a test method thereof, which solves the shortcomings of the existing test device, such as insufficient sealing, few testable working conditions, and static testing. The present invention comprises an inner tube and an outer tube, wherein an inner bracket is fixed in the inner tube, and the inner bracket is fixed on a steerable and movable telescopic vehicle. The inner tube is located inside the outer tube, and the tail is closed; a disposable inner wall plate is fixed on the outer tube body, a shield tail brush is welded on the inner wall plate, an outer tube rear cover is installed at the tail of the outer tube, and a sealing gasket is installed in the outer tube rear cover. The present invention can simulate the excavation state of the shield machine during actual construction. The test device can test the waterproofing effect of the interaction between different greases and different shield tail brushes under different shield tail gaps. The use of a disposable inner wall plate increases the speed and simplicity of the test. At the same time, the scalability of the model provides more accurate data support for actual engineering.

[0041] Specifically, the present invention provides a dynamic scale model of a shield machine's tail waterproofing system, comprising a tractor equipped with a U-bolt fixing device. The U-bolt is located on a lifting bracket, which is located on a rotating disk. A directional wheel (1) is mounted below the rotating disk. The U-bolt grips an inner tube movable rod. The inner tube movable rod includes a long rod inner bracket in the longitudinal direction, a horizontal rod inner bracket in the width direction mounted on the long rod inner bracket, and a vertical rod inner bracket in the height direction mounted on the long rod inner bracket. Preferably, the plane formed by the vertical rod inner bracket and the horizontal rod inner bracket is perpendicular to the long rod inner bracket.

[0042] Preferably, two upper and lower grease injection holes are provided at the corresponding grease cavity portion on the inner cylinder, and two left and right flat film pressure sensors are provided at the corresponding grease cavity portion in the horizontal direction.

[0043] The disposable shield tail comprises a disposable inner wall plate and fixing bolt holes on both sides of the circumference, and the shield tail brush is welded to the inner wall plate.

[0044] Preferably, the sealed rear cover includes an outer cylinder (rotating) rear cover, a sealing gasket, a water pressure sensor, and a water injection hole. The sealing gasket is placed inside the outer cylinder rotating rear cover, and the water pressure sensor and the water injection hole are installed on the outer cylinder rotating rear cover.

[0045] Preferably, the shield tail brush, inner cylinder, outer cylinder and rotating rear cover together form a closed grease chamber and a closed water chamber.

[0046] Preferably, the inner support system is fixed to the inner wall of the inner tube, which can firmly control the orientation change of the inner tube and accurately simulate the tunneling posture of the shield machine.

[0047] Preferably, the power tractor can complete position adjustment in three directions of XYZ through a rotating disc and a lifting bracket, and slide on the ground through the directional wheels I.

[0048] Preferably, the sealed rear cover is a detachable rotating rear cover.

[0049] Preferably, the outer cylinder is fixed on the directional wheel, the inner cylinder and the outer cylinder are both scaled cylinders, and the inner cylinder is inside the outer cylinder.

[0050] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0052] The following examples of the present application will clearly and completely describe the technical solution. Obviously, the described examples are only some preferred embodiments of the present application, not all embodiments. Based on the examples in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0053] like Figure 1 、 2 As shown, a dynamic scale model of the shield machine tail waterproofing system includes a power tractor. The power tractor includes a U-shaped bolt 1 for fixing the long rod, a lifting bracket 2 in the height direction, a rotating disk 3 rotating on the XY plane, and a directional wheel 14 moving horizontally on the ground. The power tractor can adjust the gap between the inner and outer cylinders and can also drive the inner cylinder to move within the outer cylinder space, realistically simulating the excavation behavior of the tunnel shield machine during excavation.

[0054] like Figure 1 、 3 As shown, a dynamic scale model of the waterproof system at the tail of a shield machine includes an inner tube movable rod. The inner tube movable rod includes a long rod inner bracket 5 in the length direction, a horizontal rod inner bracket 7 in the width direction, and a vertical rod inner bracket 6 in the height direction. The inner tube movable rod is connected to a power tractor on the outside and the inner tube on the inside, receiving power from the power tractor and evenly transmitting it to the inner tube to avoid uneven force on the inner tube and save space in the inner tube for placing sensors.

[0055] like Figure 1 、 4 As shown, a dynamic scale model of the waterproofing system at the rear of a shield machine includes input and output devices. The grease chamber corresponding to the input device is provided with two upper and lower grease injection holes 14 and a water injection hole 20 on the rotating rear cover. The output device is provided with two left and right flat membrane pressure sensors 16 and a water pressure sensor 19 on the rotating rear cover at the corresponding grease chamber in the horizontal direction. The input device can simulate the grease pumping and water and soil loads during the construction of the shield machine. The output device receives the pressure of the grease chamber and the water chamber in real time through the layout of sensors. It can dynamically observe the pressure changes inside the device and analyze the dynamic change process of water flow penetrating the waterproofing system, providing data support for further prediction and remediation.

[0056] like Figure 1 、 5 As shown, a dynamic scale model of the waterproof system of the tail of a shield machine includes a disposable shield tail. The disposable shield tail includes a disposable inner wall plate 12, fixing bolt holes 10 on both sides of the circumference, and a shield tail brush 15 welded to the inner wall plate. The disposable shield tail can reduce the difficulty of the test, is easy to disassemble, facilitates the collection of data for multiple groups of experiments, and improves the test efficiency.

[0057] like Figure 1 、 5 As shown, a dynamic scale model of the waterproof system of the tail of a shield machine includes a rotating sealed rear cover. The rotating sealed rear cover includes an outer cylinder rotating rear cover 17, a sealing gasket 18, a water pressure sensor 19, and a water injection hole 20. The rotating rear cover can rotate and seal while ensuring the operating space at the end of the outer cylinder, thereby improving the waterproof strength of the test.

[0058] like Figure 1 As shown in the figure, a dynamic scaled model of the shield machine tail waterproofing system can be scaled down according to the actual shield machine model. A preliminary experiment can be set up before construction to test the shield tail waterproofing performance. The shield tail waterproofing system can be adjusted according to the experimental data, which greatly improves construction safety.

[0059] The dynamic scaled model of the shield machine tail waterproofing system can be used for simulation testing. The steps are as follows:

[0060] S1: Assemble the tractor by assembling the U-bolt 1, lifting bracket 2, rotating disc 3, and directional wheel I4 in order from top to bottom.

[0061] S2: Assemble the disposable shield tail, weld the shield tail brush 15 to the inner plate of the disposable inner wall plate 12, form a circle, overlap each other, send the assembled disposable inner wall plate 12 into the outer tube 9, and firmly fix it on the outer tube 9 through the bolt hole 10.

[0062] S3: Assemble the movable inner cylinder, overlap the long rod inner bracket 5, the horizontal rod inner bracket 7, and the vertical rod inner bracket 6 according to the length, width and height, and weld the end points to the inner cylinder 8. At the same time, install the upper and lower grease injection holes 14 corresponding to the grease chamber, as well as two flat film pressure sensors 16 on the left and right. The exposed end of the long rod is fixed to the tractor by the U-bolt 1.

[0063] S4: Install the sealing gasket 18 into the outer cylinder rear cover 17, and rotate the outer cylinder rear cover 17 to fix it on the outer cylinder 9. At the same time, install the water pressure sensor 19 and the water injection pipe 20 on the outer cylinder rear cover 17.

[0064] S5: Start the traction device of the head and slowly feed the inner cylinder 8 from the opening of the outer cylinder 9 until the inner cylinder 8 reaches the position of the first shield tail brush.

[0065] S6: Start the grease pump, inject grease through the grease injection hole 14, observe the oil pressure of the flat membrane pressure sensor 16, and maintain a stable oil pressure after the grease cavity is filled. At the same time, start the water pump, set a fixed water pressure and inject it into the outer cylinder 9 through the water injection hole 20, observe the water pressure of the water pressure sensor 19, and control the input pressure in real time.

[0066] S7: Start the traction device to simulate the shield machine's excavation behavior, observe the pressure changes of the flat membrane pressure sensor 16 and the water pressure sensor 19, and observe the water flow breakdown at the opening of the outer tube 9, record the data in time, and analyze and guide the engineering construction.

[0067] The present invention drives the movement of the inner tube bracket by a power tractor to simulate the activity state in the XYZ direction of the spatial plane, adjusts the distance between the inner tube and the outer tube to simulate the shield tail gap, and at the same time, the uniform forward speed of the tractor can simulate the tunneling of the shield machine. This test device can be infinitely close to the tunneling posture of the shield machine, and can simulate the stress state of the shield machine during tunneling by inputting grease and muddy water. The layout of the sensors can also monitor the actual pressure bearing capacity of the shield tail waterproof system in real time. The design of the disposable shield tail can greatly increase the speed of the experiment, avoid the waste of time and physical strength caused by cleaning, and facilitate the welding of the shield tail brush. The integrated design improves the waterproof performance and also improves the test accuracy. The design of the rotating rear cover ensures the operating space of the shield tail and improves the waterproof performance of the device.

[0068] The embodiments described above are merely specific implementations of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be imagined by any person skilled in the art within the technical scope disclosed in the present application without resorting to creative effort should be included within the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims in the present application.

Claims

1. A dynamic scale model of a shield machine tail waterproofing system, including an inner bracket, characterized by: The dynamic scale model of the tail waterproof system of the shield machine includes a traction device, an inner tube (8) and an outer tube (9), the inner tube (8) and the outer tube (9) are hollow inside, and the outer diameter of the inner tube (8) is smaller than the inner diameter of the outer tube (9); the traction device is fixedly connected to the inner bracket, the inner bracket is externally connected to the inner tube (8) and is fixedly connected to the inner tube (8), and the inner bracket includes a long rod inner bracket (5), a vertical rod inner bracket (6), and a horizontal rod inner bracket (7); the inner tube (8) is contained in the outer tube (9), the tail is sealed, and a grease cavity is set between the inner tube (8) and the outer tube (9), and the grease cavity is provided on the grease cavity. A grease injection hole (14) is provided at the bottom, a flat film pressure sensor (16) is provided at the left and right, and the outer wall of the inner cylinder (8) contacts the shield tail brush (15); the shield tail brush (15) is fixedly connected to the inner wall plate of the outer cylinder (9) and forms a sealing and waterproof system with the grease (13); the inner wall plate is fixedly connected to the outer cylinder (9); a directional wheel II (11) is installed at the lower part of the outer cylinder (9), and the tail is sealed by the outer cylinder rear cover (17); a sealing gasket (18), a water pressure sensor (19) and a water injection hole (20) are installed on the inner bottom plate of the outer cylinder rear cover (17); The traction device is a power tractor, which comprises a U-shaped bolt (1), a lifting bracket (2) in the height direction, a rotating disc (3) rotating on the xy plane, and a directional wheel I (4) moving horizontally on the ground; the long rod inner bracket (5) is fixedly mounted on the power tractor by being connected to the U-shaped bolt (1); the U-shaped bolt (1) is fixed to the upper cover plate of the lifting bracket (2); the lifting bracket (2) is connected to the rotating disc (3) below, and the rotating disc is connected to the directional wheel I (4) below.

2. The dynamic scale model of the shield machine tail waterproofing system according to claim 1 is characterized by: The inner bracket comprises a long rod inner bracket (5) in the length direction, a horizontal rod inner bracket (7) in the width direction, and a vertical rod inner bracket (6) in the height direction; a plane formed by the vertical rod inner bracket (6) and the horizontal rod inner bracket (7) is arranged perpendicular to the long rod inner bracket (5); and end points of the horizontal rod inner bracket (7) and the vertical rod inner bracket (6) are fixed to the inner wall of the inner tube (8).

3. The dynamic scale model of the shield machine tail waterproofing system according to claim 1 is characterized by: The outer cylinder (9) includes a shield tail; the shield tail includes a disposable inner wall plate (12), fixing bolt holes (10) on both sides of the circumference, and a shield tail brush (15) fixed on the inner wall plate; the shield tail brush (15) contacts the outer wall of the inner cylinder (8) and is fixedly connected to the inner plate of the disposable inner wall plate (12), the inner wall plate is a disposable inner wall plate (12), and the shield tail is a disposable shield tail.

4. The dynamic scale model of the shield machine tail waterproofing system according to claim 1 is characterized by: The shield tail brush (15) is welded to the inner plate of the disposable inner wall plate (12), forming a circle and overlapping each other to isolate the liquid; one or more shield tail brushes (15) are arranged between the inner cylinder (8) and the outer cylinder (9), and the one or more shield tail brushes (15) are all located in the gap between the two ends of the inner cylinder (8) and between the outer wall of the inner cylinder (8) and the inner plate of the disposable inner wall plate (12).

5. The dynamic scale model of the shield machine tail waterproofing system according to claim 1 is characterized by: The outer cylinder rear cover (17) is rotatably fixed on the outer cylinder (9).

6. The method for preparing a dynamic scale model of the shield machine tail waterproof system according to any one of claims 1 to 5, characterized in that: include: S1: Assemble the tractor by assembling the U-bolt (1), lifting bracket (2), rotating disc (3), and directional wheel I (4) in order from top to bottom; S2: Assemble the disposable shield tail, weld the shield tail brush (15) to the inner plate of the disposable inner wall plate (12), form a circle, and overlap each other; place the assembled disposable inner wall plate (12) into the outer cylinder (9), and fix it to the outer cylinder (9) through the bolt hole (10); S3: Assemble the movable inner cylinder, overlap the long rod inner bracket (5), the horizontal rod inner bracket (7), and the vertical rod inner bracket (6) in the length, width, and height directions, and fix the end points of the horizontal rod inner bracket (7) and the vertical rod inner bracket (6) to the inner wall of the inner cylinder (8); at the same time, set two grease injection holes (14) at the upper and lower corresponding positions of the grease cavity and set two flat film pressure sensors (16) at the left and right corresponding positions, and fix the exposed end of the long rod to the tractor by a U-shaped bolt (1); S4: Install the sealing gasket (18) into the outer cylinder rear cover (17), and rotate the outer cylinder rear cover (17) to fix it on the outer cylinder (9). At the same time, install the water pressure sensor (19) and the water injection hole (20) on the outer cylinder rear cover (17).

7. Application of the dynamic scale model of the shield machine tail waterproofing system according to any one of claims 1 to 5, characterized in that: The application method includes: (a) Start the traction device of the power tractor and slowly feed the inner cylinder (8) from the opening of the outer cylinder (9) until the inner cylinder (8) reaches the position of the first shield tail brush (15); (b) Start the grease pump and inject grease into the grease cavity between the inner cylinder (8) and the outer cylinder (9) through the grease injection hole (14), observe the oil pressure of the flat film pressure sensor (16), and maintain a stable oil pressure after the grease cavity is filled. At the same time, start the water pump and set a fixed water pressure to inject water or muddy water into the inner part of the outer cylinder (9) through the water injection hole (20), observe the pressure of the water pressure sensor (19), and control the input pressure in real time; (c) Start the traction device to simulate the tunneling behavior of the shield machine, observe the pressure changes of the flat membrane pressure sensor (16) and the water pressure sensor (19), and observe the water flow breakdown at the opening of the outer cylinder (9), record the data in time, and analyze and guide the construction of the project.

8. The application of the dynamic scale model of the shield machine tail waterproofing system according to claim 7 is characterized by: The uniform forward speed of the tractor simulates the excavation of the shield machine; the dynamic scale model of the shield machine's tail waterproofing system is proportionally reduced according to the actual shield machine, so as to facilitate multiple tests to obtain corresponding data and adjust the shield machine's tail waterproofing system according to the experimental data.

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