Tunnel boring machine shield and broken rock-soil friction characteristic testing device

Abstract

The utility model relates to the technical field of tunneling friction testing, and discloses a device for testing friction characteristics of a shield of a tunneling machine and crushed rock soil. The technical problems that in the prior art, real geological conditions cannot be simulated, so that test results are not accurate enough, effective monitoring and control means are lacked, manual operation is relied on, test efficiency is reduced, repetition is difficult, and test reliability is affected are solved. The experimental device comprises an experimental box body internally provided with a pressure generating unit, baffle jacking assemblies are installed on the left side and the right side of the experimental box body through movable baffles, fixed baffles are arranged on the front side and the rear side of the experimental box body, a through circular hole is formed in the middle of each fixed baffle, and a sealing cylinder is arranged in each circular hole in a penetrating mode. A cylinder jacking assembly is installed on one side of the sealing cylinder. The utility model provides an effective test platform, which is favorable for improving the performance and safety of the tunnel boring machine, reducing the test cost and time, and improving the working efficiency.

Description

Technical Field

[0001] The utility model relates to the technical field of tunnel boring friction testing, in particular to a device for testing friction characteristics between a tunnel boring machine shield and broken rock and soil. Background Art

[0002] With the development of my country's tunneling industry, the number of tunnels constructed using tunnel boring machines (TBMs) is increasing. In my country, tunnel boring machines are generally categorized as TBMs (for rock environments) and shield machines (for soil environments). The shield of a tunnel boring machine (TBM) directly contacts the surrounding rock, providing support and protection. However, excessive friction between the shield and the surrounding rock can severely hamper tunneling. For example, when a TBM encounters a crushed zone during construction, the crushed surrounding rock presses against the shield. Excessive friction can easily cause the TBM to jam, severely impacting the project schedule and resulting in significant economic losses. Similarly, the frictional characteristics between the shield and the soil are crucial for selecting shield machine excavation parameters and developing drag reduction technologies. Therefore, key technical challenges remain, such as how to simulate tunneling under realistic geological conditions, how to monitor and control the confining pressure of the shield model, and how to ensure the accuracy and reliability of experimental data.

[0003] Chinese patent document 202311519345.3 in the prior art discloses a comprehensive performance testing system for a tunnel plugging airbag, comprising: a testing device and a cloud platform; the testing device comprises a simulation chamber, an airbag, a sensor, and a conveying device; there are multiple conveying devices in the simulation chamber; each conveying device comprises a conveyor belt made of a plurality of materials with different friction coefficients to simulate the friction of different tunnel stones; the airbag is arranged in the middle of the simulation chamber and in contact with the conveyor belt; the sensor is used to measure the deformation information, air pressure, temperature in the simulation chamber, and gas concentration after the airbag is subjected to force.

[0004] However, the above schemes present at least the following technical challenges during implementation: They fail to simulate realistic geological conditions, resulting in inaccurate test results; they lack effective monitoring and control measures, and rely on manual operation, which reduces test efficiency and makes repeatability difficult, thus impacting test reliability. Therefore, a device for testing the friction characteristics between a tunnel boring machine shield and crushed rock and soil is urgently needed. Summary of the Invention

[0005] In view of the above technical problems, the present disclosure provides a device for testing the friction characteristics of a tunnel boring machine shield and crushed rock and soil, which solves the technical problems in the existing technology that the actual geological conditions cannot be simulated, resulting in inaccurate test results, lack of effective monitoring and control means, reliance on manual operation, reduced test efficiency, difficulty in repeatability, and affecting the credibility of the test.

[0006] According to one aspect of the present disclosure, a device for testing the friction characteristics between a tunnel boring machine shield and broken rock and soil is provided, comprising an experimental box with a pressure generating unit installed inside, baffle jacking assemblies installed on the left and right sides of the experimental box via movable baffles, fixed baffles are provided at the front and rear of the experimental box, a circular opening is provided through the middle of the fixed baffle, a sealing cylinder is placed through the circular opening, and a cylinder jacking assembly is installed on one side of the sealing cylinder.

[0007] In some embodiments of the present disclosure, the steel type of the sealing cylinder is the same as that of the tunnel boring machine shield.

[0008] In some embodiments of the present disclosure, the baffle jacking assembly includes at least one hydraulic cylinder, wherein a piston end of the hydraulic cylinder is connected to the movable baffle and a rear end is connected to the fixed bracket.

[0009] In some embodiments of the present disclosure, the cylinder jacking assembly includes at least one hydraulic cylinder, the piston end of the hydraulic cylinder is connected to one side of the sealing cylinder 6, and the rear end is connected to the fixed bracket.

[0010] In some embodiments of the present disclosure, a rolling bearing is installed at the connection between the circular hole and the sealing cylinder.

[0011] In some embodiments of the present disclosure, the upper cover plate of the experimental box is installed with an upper cover plate jacking assembly, and the upper cover plate jacking assembly includes at least one hydraulic cylinder, and the piston end of the hydraulic cylinder is connected to the upper cover plate and the rear end is connected to the fixed bracket.

[0012] In some embodiments of the present disclosure, an earth pressure box is arranged inside the movable baffle to monitor the pressure inside the box and quantify the confining pressure of the shield model.

[0013] In some embodiments of the present disclosure, strain gauges are attached to the inner side of the test box to determine the confining pressure on the shield model.

[0014] In some embodiments of the present disclosure, the strain gauge is connected to the analog signal end of the AD conversion chip, the digital signal end of the AD conversion chip is connected to the main control chip, the control signal output end of the main control chip is connected to the pressure generating unit, and the pressure generating unit includes a gas compressor.

[0015] In some embodiments of the present disclosure, the SPI interface of the main control chip is connected to a data isolation chip to perform isolated communication with the main control chip.

[0016] The beneficial effects of the present invention are:

[0017] 1. By installing a pressure generating unit inside the experimental box, different geological conditions can be simulated, making the test results closer to the actual situation; the accuracy of the test results is significantly improved.

[0018] 2. Using sensors such as earth pressure cells and strain gauges, the pressure inside the box and the confining pressure on the shield model can be monitored in real time, thereby achieving effective monitoring and control.

[0019] 3. Through the control of the hydraulic cylinder and the main control chip, the test process can be automated, reducing dependence on manual operation, improving test efficiency, and making the test repeatable, thereby improving the credibility of the test results.

[0020] 4. Through the cooperation of AD conversion chip and main control chip, the sensor signal can be collected and processed to provide accurate data support for the experiment.

[0021] 5. The SPI interface is connected to the data isolation chip, which realizes the isolated communication between the main control chip and external devices, and improves the stability and security of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of the device for testing the friction characteristics between the tunnel boring machine shield and crushed rock and soil;

[0023] Figure 2 This is a schematic diagram of the structure of the device for testing the friction characteristics between the tunnel boring machine shield and crushed rock and soil from another perspective;

[0024] The names of the components in the figure are: 1. Experimental box; 2. Movable baffle; 3. Baffle jacking assembly; 4. Fixed baffle; 5. Circular hole; 6. Sealing cylinder; 7. Cylinder jacking assembly; 8. Hydraulic cylinder; 9. Fixed bracket; 10. Upper cover jacking assembly; 11. Upper cover. DETAILED DESCRIPTION

[0025] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention. Example 1

[0026] This example discloses a device for testing the friction characteristics between a tunnel boring machine shield and crushed rock and soil. Figures 1 to 2 , including an experimental box 1 with a pressure generating unit installed inside, baffle jacking components 3 are installed on the left and right sides of the experimental box 1 through movable baffles 2, fixed baffles 4 are set at the front and back of the experimental box 1, and a through circular hole 5 is set in the middle of the fixed baffle 4. A sealing cylinder 6 is placed through the circular hole 5, and a cylinder jacking component 7 is installed on one side of the sealing cylinder 6.

[0027] The steel type of the sealing cylinder 6 is the same as that of the tunnel boring machine shield.

[0028] The baffle jacking assembly 3 includes at least one hydraulic cylinder 8 , the piston end of the hydraulic cylinder 8 is connected to the movable baffle 2 , and the rear end is connected to the fixed bracket 9 .

[0029] The cylinder jacking assembly 7 includes at least one hydraulic cylinder 8 , the piston end of the hydraulic cylinder 8 is connected to one side of the sealing cylinder 6 , and the rear end is connected to the fixed bracket 9 .

[0030] A rolling bearing is installed at the connection between the circular hole 5 and the sealing cylinder 6.

[0031] The upper cover plate of the experimental box 1 is installed with an upper cover plate jacking assembly 10, which includes at least one hydraulic cylinder 8, the piston end of the hydraulic cylinder 8 is connected to the upper cover plate 11, and the rear end is connected to the fixed bracket 9.

[0032] An earth pressure box is placed inside the movable baffle 2 to monitor the pressure inside the box and quantify the confining pressure of the shield model.

[0033] Strain gauges are attached to the inside of the experimental box to determine the confining pressure on the shield model.

[0034] The strain gauge is connected to the analog signal end of the AD conversion chip, the digital signal end of the AD conversion chip is connected to the main control chip, and the control signal output end of the main control chip is connected to the pressure generating unit, which includes a gas compressor.

[0035] The SPI interface of the main control chip is connected to the data isolation chip to perform isolated communication with the main control chip.

[0036] This device can measure the friction characteristics between the shield and specific surrounding rock:

[0037] Assuming that the radius of the shield model is R and the contact length with the test soil is L, the contact area is S=2πRL

[0038] The thrust of the shield model is F1, the confining pressure is F2, the friction force is f, and the friction coefficient is u

[0039] Then f = F1 = 2πRL F2u

[0040] The friction coefficient u at different confining pressures can be obtained, including the static friction coefficient and the sliding friction coefficient.

[0041] During operation, the experimental chamber is filled with gas and pressurized to simulate geological conditions. The pressure generating unit is activated to raise the pressure inside the chamber to the set value. The baffle jacking assembly pushes the movable baffle forward, simulating the shield's propulsion. The cylinder jacking assembly pushes the sealing cylinder forward, simulating the rotary cutting action of the cutterhead. The upper cover jacking assembly pushes the upper cover forward, simulating the rock pressure at the top. The earth pressure cell monitors the pressure inside the chamber and quantifies the confining pressure of the shield model. The strain gauge deforms under pressure, generating impedance changes that are converted to actual pressure values. An A / D converter module in the data acquisition terminal, such as the AD7982, converts this value into a digital signal. A data isolation chip is used to eliminate erroneous data. The optimized data is then processed by the STM32 main control chip, whose SPI interface is connected to the ADUM1411 data isolation chip. This device can simulate real geological conditions and tunnel excavation processes, monitor and control the confining pressure of the shield model, and ensure the accuracy and reliability of experimental data. At the same time, automatic control can improve the accuracy, safety and efficiency of the test, reduce the test cost and time, and improve the repeatability of the test.

[0042] Although some preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including all changes and modifications that fall within the scope of the present invention as well as the preferred embodiments.

[0043] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of this application and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A device for testing friction characteristics between a tunnel boring machine shield and broken rock and soil, characterized by: It includes an experimental box with a pressure generating unit installed inside. The left and right sides of the experimental box are equipped with baffle jacking assemblies through movable baffles. Fixed baffles are set at the front and back of the experimental box. A through circular hole is set in the middle of the fixed baffle. A sealing cylinder is placed through the circular hole. A cylinder jacking assembly is installed on one side of the sealing cylinder.

2. The device for testing friction characteristics between a tunnel boring machine shield and broken rock and soil according to claim 1, wherein: The steel type of the sealing cylinder is the same as that of the tunnel boring machine shield.

3. The device for testing friction characteristics between a tunnel boring machine shield and broken rock and soil according to claim 1, wherein: The baffle jacking assembly includes at least one hydraulic cylinder, the piston end of the hydraulic cylinder is connected to the movable baffle, and the rear end is connected to the fixed bracket.

4. The device for testing friction characteristics between a tunnel boring machine shield and broken rock and soil according to claim 1, wherein: The cylinder jacking assembly includes at least one hydraulic cylinder, the piston end of the hydraulic cylinder is connected to one side of the sealing cylinder 6, and the rear end is connected to the fixed bracket.

5. The device for testing friction characteristics between a tunnel boring machine shield and broken rock and soil according to claim 1, wherein: A rolling bearing is installed at the connection between the circular hole and the sealing cylinder.

6. The device for testing friction characteristics between a tunnel boring machine shield and broken rock and soil according to claim 1, wherein: The upper cover plate of the experimental box is installed with an upper cover plate jacking assembly, and the upper cover plate jacking assembly includes at least one hydraulic oil cylinder, the piston end of the hydraulic oil cylinder is connected to the upper cover plate, and the rear end is connected to the fixed bracket.

7. The device for testing friction characteristics between a tunnel boring machine shield and broken rock and soil according to claim 1, wherein: An earth pressure box is arranged inside the movable baffle to monitor the pressure inside the box and quantify the confining pressure of the shield model.

8. The device for testing friction characteristics between a tunnel boring machine shield and broken rock and soil according to claim 1, wherein: Strain gauges are attached to the inside of the experimental box to determine the confining pressure on the shield model.

9. The device for testing friction characteristics between a tunnel boring machine shield and broken rock and soil according to claim 8, characterized in that: The strain gauge is connected to the analog signal end of the AD conversion chip, the digital signal end of the AD conversion chip is connected to the main control chip, the control signal output end of the main control chip is connected to the pressure generating unit, and the pressure generating unit includes a gas compressor.

10. The device for testing friction characteristics between a tunnel boring machine shield and broken rock and soil according to claim 9, characterized in that: The SPI interface of the main control chip is connected to the data isolation chip to perform isolated communication with the main control chip.

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