Shield tail sealing simulation test device and test method

Abstract

According to the shield tail sealing simulation test device and test method, a shield tail structure is truly restored, and compared with an existing reduced scale model test device, the shield tail sealing simulation test device and test method are more suitable for actual engineering. The shield tail brush spacing, the number of sealing cavities and the shield tail gap can be changed according to parameters required by different projects by flexibly adjusting the structure of the device, shield tail structures of different projects are subjected to simulation reduction, engineering adaptability inspection of shield tail sealing grease is carried out, a basis is provided for model selection of shield tail sealing grease in shield tunnel construction, and the construction efficiency is improved. The problem that in current tunnel construction, type selection of shield tail sealing grease mainly depends on engineering experience is solved.

Description

Technical Field

[0001] This invention relates to the technical field of shield tail seal testing devices, specifically a shield tail seal simulation test device and test method. Background Technology

[0002] Tail sealing is a crucial step in shield tunneling construction. Tail sealing grease, as the core functional material in tail sealing, directly affects the smooth and successful progress of the project. During shield tunneling, the tail sealing grease must work in conjunction with the tail structure and grease injection scheme of different projects to effectively prevent groundwater and mud from intruding into the shield machine. Simultaneously, it must possess good pumpability to ensure long-distance pumping and uniform filling of the tail gap.

[0003] The current performance testing devices and methods for shield tail sealing grease mainly have the following problems: 1. Currently, the evaluation of shield tail sealing grease mainly relies on two independent indicators: water pressure resistance and pumpability. It is impossible to achieve a comprehensive evaluation of the entire process of pumping-filling-grouting pressurization-dynamic tunneling sealing for different shield tail structures of tunnel boring machines.

[0004] 2. Most existing shield tail sealing grease model test devices are based on scaled-down models, which have certain deficiencies in simulating shield tail structure and different working conditions. They cannot simulate and reproduce shield tail brush spacing, shield tail gap, difference in front and rear shield tail gap, number of sealing cavities, graded grease injection pressure, and water pressure for different projects. They also lack supporting shield tail sealing grease performance testing methods and evaluation standards.

[0005] 3. Existing shield tail seal model test devices cannot intelligently calculate and decide on grease injection pressure for different working conditions, and cannot solve the problem of relying on experience to set grease injection pressure in current shield tunnel engineering.

[0006] 4. Most existing shield tail seal model test devices are designed for conventional working conditions and are difficult to simulate the construction conditions of dynamic tunneling under high water pressure, making it difficult to address the issues of shield tail seal grease testing and selection in underwater high-pressure shield tunnel projects. Summary of the Invention

[0007] The purpose of this invention is to provide a shield tail sealing simulation test device and method. By reproducing the actual shield tail structure and construction parameters of an engineering project, simulation tests can be performed on different engineering parameters. Through shield tail brush spacing adjustment, shield tail gap adjustment, graded adjustment of grease injection pressure, grouting pressure adjustment, synchronous grease injection and grouting simulation, and shield tunneling posture simulation, targeted and realistic shield tail sealing tests and full-process performance verification of shield tail sealing grease can be achieved, thus solving the problems in the prior art.

[0008] The technical solution adopted by this invention to solve its technical problem is: a shield tail sealing simulation test device, including a reaction frame, a test mechanism installed inside the reaction frame, the test mechanism including a top plate fixed on the reaction frame, a bottom plate that can be vertically raised and lowered at the bottom of the top plate, several rows of shield tail brushes installed at the bottom of the top plate, the length direction of each shield tail brush being arranged perpendicular to the length direction of the top plate, a grease injection valve installed on the upper part of the top plate between adjacent shield tail brushes, side plates provided on both sides of the top plate and bottom plate along their length direction, and a [missing information - likely a design feature] at one end of the top plate and bottom plate along their length direction. The front plate, including the top plate, bottom plate, tail brush, and side plates, forms a relatively closed sealed cavity. A grease injection valve is connected to the sealed cavity. The top plate, bottom plate, tail brush, and front plate also form a relatively closed pressure cavity. A pressure valve connected to the pressure cavity is installed on the top plate. A sliding plate that can move along the length direction is also provided on the bottom plate, moving closer to the front plate. Pressure sensors and temperature sensors are also installed at the bottom of the top plate corresponding to the pressure cavity and each sealed cavity, and are connected to the main control system via control circuitry. Both the top and bottom plates are arc-shaped plates. Several rows of bolt holes are opened on the top plate, and connecting bolts that mate with the bolt holes are installed on the tail brush. Several reinforcing plates arranged along the width direction are also provided on the top plate. A first sealing ring is installed on the inner circumference of the side plate, and a second sealing ring is installed on the inner circumference of the front plate. A jack is installed on the reaction frame, and a lifting platform is installed on the telescopic rod of the jack. A support frame is provided at the bottom of the bottom plate, and the support frame is located on the lifting platform. The reaction frame has a vertically arranged vertical displacement cylinder at the end away from the front plate. A lifting seat is installed on the piston rod of the vertical displacement cylinder. A horizontally arranged electric push rod is installed on the lifting seat. A hinge seat is installed at the end of the sliding plate. The piston rod end of the electric push rod is provided with a hinge shaft that cooperates with the hinge seat. After the electric push rod moves vertically to the same horizontal position as the sliding plate, the extension and retraction of the piston rod of the electric push rod can drive the sliding plate to move along the length direction of the bottom plate.A method for conducting tests using a shield tail sealing simulation test device under standard operating conditions includes the following steps: ① Adjusting the height of the base plate to maximize the distance between the top plate and the base plate, facilitating the subsequent installation of the shield tail brush, and moving the sliding plate to an initial position away from the front plate between the base plate and the top plate; ② Installing 2-4 shield tail brushes at a set position at the bottom of the top plate, with a spacing of 400-550mm between adjacent shield tail brushes, forming 1-3 sealing cavities; ③ Applying a hand-applied shield tail sealing grease to each sealing cavity and shield tail brush; ④ Adjusting the height of the base plate to maximize the distance between the top plate and the base plate. The distance between the plates is 40-110mm. Then, side plates and front plates are installed between the top and bottom plates to form a closed sealing cavity and pressure cavity between them. ⑤ A 5-25m grease injection pipe is installed on the grease injection valve and connected to the grease injection pump. The grease injection valve and pump are opened, and the pump pressure is adjusted to 10-50 bar. Pump-type shield tail sealing grease is injected into the sealing cavity. The grease injection valve is adjusted so that the pressure in each sealing cavity is 0.5-4.0 MPa. ⑥ A pressure pipe is installed on the pressure valve and connected to the pressure pump. The pressure pump is opened and the pressure is set to 0.5-4 MPa. 0MPa, inject water or grout into the pressure chamber, observe and record the pressure sensor readings, and record the pressure fluctuation within 10 minutes. If the pressure fluctuation is less than 15%, the static seal is good; if the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified; if the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as sample seepage; if the seepage is a water-oil mixture, it is recorded as mixed seepage. ⑦ Set the moving speed of the sliding plate to 1-12mm / s. The moving plate moves closer to the front plate along the length of the base plate, and the pressure sensor reading fluctuation is recorded. If the pressure fluctuation is less than 15%, the dynamic seal is good. If the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as sample seepage. If the seepage is a water-oil mixture, it is recorded as mixed seepage. ⑧ Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.A method for conducting tests using a shield tail sealing simulation test device under synchronous grouting conditions includes the following steps: ① Adjusting the height of the base plate to maximize the distance between the top plate and the base plate, facilitating the subsequent installation of the shield tail brush, and moving the sliding plate to an initial position away from the front plate between the base plate and the top plate; ② Installing 2-4 shield tail brushes at a set position at the bottom of the top plate, with a spacing of 400-550mm between adjacent shield tail brushes, forming 1-3 sealing cavities; ③ Adjusting the height of the base plate to make the distance between the top plate and the base plate 40-110mm, and then installing... Install side plates and front plates to form a closed sealing cavity and pressure cavity between the top plate and the bottom plate; ④ Install a 5-25m grease injection pipe on the grease injection valve and connect it to the grease injection pump, and install a pressure pipe on the pressure valve and connect it to the pressure pump. Open the grease injection valve and the grease injection pump, adjust the grease injection pump pressure to 10-50 bar, and inject pump-type shield tail sealing grease into the sealing cavity. After the sealing cavity is full of grease and the pressure sensor reading reaches 0.5MPa, open the pressure pump and set the pressure to 0.5-4.0MPa, and inject water or grout into the pressure cavity, always maintaining the pressure inside the sealing cavity higher than that inside the pressure cavity. The pressure is 0.5 MPa higher than the set value; ⑤ After the pressure in the pressure chamber reaches the set value, observe and record the pressure sensor readings, and record the pressure fluctuation within 10 minutes. If the pressure fluctuation is less than 15%, the static seal is good; if the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified; if the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as sample seepage; if the seepage is a water-oil mixture, it is recorded as mixed seepage; ⑥ Set the moving speed of the sliding plate to 1-12 m. m / s, the sliding plate moves closer to the front plate along the length of the base plate, and the pressure sensor reading fluctuation is recorded. If the pressure fluctuation is less than 15%, the dynamic seal is good. If the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as sample seepage. If the seepage is a water-oil mixture, it is recorded as mixed seepage. ⑦ Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.A method for conducting tests using a tail shield sealing simulation test device under simulated up-and-down shield tunneling attitude conditions includes the following steps: ① Adjusting the height of the bottom plate to maximize the distance between the top plate and the bottom plate, facilitating the subsequent installation of the tail shield brush, and moving the sliding plate to an initial position away from the front plate between the bottom plate and the top plate; ② Installing 2-4 tail shield brushes at a set position at the bottom of the top plate, with a spacing of 400-550mm between adjacent tail shield brushes, forming 1-3 sealing cavities; ③ Applying a hand-applied tail shield sealing grease to each sealing cavity and the tail shield brush; ④ Adjusting the height of the bottom plate so that the front end of the top plate is aligned with the front end of the bottom plate. The distance between the top and bottom plates is 40-110mm, and the distance between the rear ends of the top and bottom plates is 40-110mm, so that the slope of the bottom plate is 0-2.0%. Then, the side plates and front plates are installed between the top and bottom plates to form a closed sealing cavity and pressure cavity between the top and bottom plates; ⑤ Install a 5-25m grease injection pipe on the grease injection valve and connect it to the grease injection pump. Open the grease injection valve and the grease injection pump, adjust the grease injection pump pressure to 10-50 bar, and inject pump-type shield tail sealing grease into the sealing cavity. Adjust the grease injection valve so that the pressure of each sealing cavity is 0.5-4.0MPa; ⑥ Install a pressure valve on the pressure valve. Connect the pipe to the pressure pump, turn on the pressure pump and set the pressure to 0.5-4.0 MPa. Inject water or grout into the pressure chamber, observe and record the pressure sensor readings, and record the pressure fluctuation within 10 minutes. If the pressure fluctuation is less than 15%, the static seal is good; if the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified; if the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as sample seepage; if the seepage is a water-oil mixture, it is recorded as mixed seepage. ⑦ Set the moving speed of the sliding plate. The rate is 1-12 mm / s. The sliding plate moves closer to the front plate along the length of the base plate, and the pressure sensor reading fluctuation is recorded. If the pressure fluctuation is less than 15%, the dynamic seal is good. If the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as sample seepage. If the seepage is a water-oil mixture, it is recorded as mixed seepage. ⑧ Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.A method for conducting tests using a shield tail sealing simulation test device under simulated working conditions of synchronous grouting and upward / downward shield attitude includes the following steps: ① Adjusting the height of the bottom plate to maximize the distance between the top plate and the bottom plate, facilitating the subsequent installation of the shield tail brush, and moving the sliding plate to an initial position away from the front plate between the bottom plate and the top plate; ② Installing 2-4 shield tail brushes at a set position at the bottom of the top plate, with a spacing of 400-550mm between adjacent shield tail brushes, forming 1-3 sealing cavities; ③ Adjusting the height of the bottom plate so that the distance between the front end of the top plate and the front end of the bottom plate is 40-110mm, and the distance between the rear end of the top plate and the rear end of the bottom plate is... The distance between the top and bottom plates is 40-110mm, resulting in a bottom plate slope of 0-2.0%. Then, side plates and a front plate are installed between the top and bottom plates to form a closed sealing cavity and pressure cavity. ④ A 5-25m grease injection pipe is installed on the grease injection valve and connected to the grease injection pump. A pressure pipe is installed on the pressure valve and connected to the pressure pump. The grease injection valve and pump are opened, and the pump pressure is adjusted to 10-50 bar. Pump-type shield tail sealing grease is injected into the sealing cavity. Once the sealing cavity is full of grease and the pressure sensor reading reaches 0.5MPa, the pressure pump is opened and the pressure is set to 0.5-4.0MPa. ⑤ Inject water or grout into the pressure chamber, and always maintain the pressure in the sealed chamber 0.5 MPa higher than the pressure in the pressure chamber; ⑥ After the pressure in the pressure chamber reaches the set value, observe and record the pressure sensor readings, and record the pressure fluctuation within 10 minutes. If the pressure fluctuation is less than 15%, the static seal is good; if the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified; if the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as sample seepage; if the seepage is a water-oil mixture, it is recorded as mixed seepage; ⑦ Set the sliding... The moving plate moves at a speed of 1-12 mm / s. The sliding plate moves closer to the front plate along the length of the base plate, and the pressure sensor reading fluctuation is recorded. If the pressure fluctuation is less than 15%, the dynamic seal is good. If the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the exudate is an intact grease sample, it is recorded as sample leakage. If the exudate is a water-oil mixture, it is recorded as mixed leakage. ⑦ Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.The experimental device can collect and learn historical experimental data based on the LSTM neural network on the main control system, and complete the prediction of the sealing cavity pressure in the next 3-25 seconds. Combined with the corresponding sealing effect evaluation method, it provides the optimal grease injection pressure for different working conditions. The main control system is an external computer. The historical experimental data includes pressure in the pressure cavity, sealing cavity pressure, shield tail brush spacing, shield tail gap, tunneling inclination angle, tunneling speed, grease injection pressure, and temperature. The pressure in the pressure cavity and sealing cavity pressure are collected by pressure sensors, and the temperature is collected by temperature sensors. The shield tail brush spacing, shield tail gap, tunneling inclination angle, tunneling speed, and grease injection pressure are manually input. The LSTM neural network has a data sampling period Δt of 0.1-0.5s. At any given time, the observation vector includes the pressure in the pressure cavity pressure P. e (t), sealing cavity pressure: P s1 (t), P s2 (t), P s3 (t) (average of two pressure sensors for each chamber), temperature T s1 (t), T s3 (t), shield tail clearance g(t), sliding plate speed (tunneling speed) v(t), historical grease injection pressure setting value P injs1 (t-Δt), P injs2 (t-Δt), P injs3 (t-Δt). Construct a sliding time window of length L=30-50 (corresponding to data from the past 3-25 seconds): W t = {O[t-L+1], O[t-L+2], ..., Ot}where W t The dimension is L×N f N f This is the dimension of Ot. This is the basic input to the LSTM model. The model predicts the sealing state in the next H steps (H=30-50, corresponding to the next 3-25 seconds) based on the input data and historical experimental data learned from it. The pressure of each sealing cavity in the future is denoted as P. si (t+1),..., P si (t+H); The future sealing state is evaluated using predicted sealing cavity pressure data. The sealing effect evaluation method is as follows: intercavity pressure gradient: Grad ij (t)=|P si (t) - P sj (t)| / d ij , where d ij P is the distance between sealed cavities i and j. si (t) is the algorithm-predicted pressure of the i-th sealing cavity at time t, P sj (t) is the algorithm-predicted pressure of the j-th sealing cavity at time t; pressure maintenance rate: R si(t+k|t) = P si (t+k) / P e (t), where P si (t+k) is the algorithm-predicted pressure of the i-th sealing cavity at time t+k, P e (t) is the observed pressure in the pressure chamber at time t; Leakage risk index: LR(t) = α × Sigmoid{β × P e (t)-β×min[P s (t)]}+γ×Sigmoid{δ× [|v(t)|]} where, P e (t) represents the observed pressure in the pressure chamber at time t, min[P s [(t)] is the predicted minimum pressure at time t among the three sealed cavities. α , β , γ , δ These are adjustable weight parameters. α The value range is 0.4 to 0.6. β The value range is 0.8 to 1.2. γ The value range is 0.3 to 0.5. δ The range is 0.05~0.15; the optimal grease injection pressure decision method is as follows: if LR < 0.3, the optimal grease injection pressure is the current grease injection pressure plus or minus 0.2 bar; if 0.3 ≤ LR < 0.6, the optimal grease injection pressure is the current grease injection pressure plus 0.5 bar to 1.0 bar; if 0.6 ≤ LR < 0.8, the optimal grease injection pressure is the current grease injection pressure plus 1.0 bar to 2.0 bar; if LR ≥ 0.8, the optimal grease injection pressure is the current grease injection pressure plus 2.0 bar to 3.0 bar.

[0009] The positive effects of this invention are as follows: 1. This invention provides a realistic recreation of the shield tail structure, which is more closely aligned with actual engineering practices compared to existing scaled-down model testing devices. By flexibly adjusting its structure, this invention can modify the shield tail brush spacing, the number of sealing cavities, and the shield tail gap according to the parameters required for different projects. It simulates and recreates the shield tail structure for different projects, conducting engineering adaptability tests on the shield tail sealing grease. This provides a basis for selecting shield tail sealing grease in shield tunnel construction, solving the problem that the selection of shield tail sealing grease in current tunnel construction mainly relies on engineering experience.

[0010] 2. Compared with existing evaluation methods that rely solely on independent indicators such as water pressure resistance and pumpability, this invention achieves specific simulation of different working conditions by flexibly adjusting the difference in the gap between the front and rear shield tails, the sliding plate rate, the grease injection pressure, and the shield tail pressure. It can comprehensively reflect the overall capabilities of the shield tail sealing grease in the entire process of pumping, filling, grouting and pressurizing, and dynamic tunneling sealing under different working conditions. Furthermore, this invention provides suitable test methods and evaluation standards for different working conditions.

[0011] 3. To address the current problem of relying on experience to set grease injection pressure in shield tunnel engineering, this invention can be combined with LSTM neural network to perform deep learning on the detection data, realize the prediction of the sealing cavity pressure data at future moments, and realize the evaluation of the sealing state through corresponding calculation methods, providing the optimal grease injection pressure for different shield tail structures and different working conditions.

[0012] 4. Compared with existing shield tail model test devices, this invention achieves simulation of dynamic tunneling conditions under high water pressure of 4.0MPa through reaction frame structure, jack support, independent fixing of top plate and sliding plate design, and realizes the detection and selection of shield tail sealing grease required for underwater tunnel projects with high construction risks and difficulties. Attached Figure Description

[0013] Figure 1 This is a three-dimensional structural schematic diagram of the experimental device in this invention; Figure 2 This is a front view of the experimental apparatus in this invention; Figure 3 yes Figure 2 The left view; Figure 4 yes Figure 2 The right view; Figure 5 yes Figure 2 Top view; Figure 6 yes Figure 5 Rotate the sectional view along axis AA clockwise by 90 degrees; Figure 7 yes Figure 5 Sectional view along the BB direction; Figure 8 This is a structural schematic diagram of the top slab; Figure 9 This is a structural diagram of the base plate; Figure 10 This is a schematic diagram of the connection between the electric actuator and the sliding plate; Figure 11 yes Figure 7 A magnified view of part I. Detailed Implementation

[0014] The shield tail sealing simulation test device described in this invention, such as Figure 1-9 As shown, the device includes a reaction frame 1, within which a testing mechanism is installed. The reaction frame 1, which can be made of I-beams, serves not only as the installation foundation for the device but also to withstand the weight of the device and the reaction forces generated by the grease injection pressure and the pressure in the pressurization chamber. This device is used before shield tunnel construction to select the appropriate tail sealant based on actual engineering parameters, and to simulate and test the sealing capability of the tail sealant system, providing parameter guidance for engineering construction and tail sealant production.

[0015] The testing mechanism includes a top plate 2 fixed to a reaction frame 1. The bottom of the top plate 2 has a vertically movable base plate 3. Several rows of tail shield brushes 4 are installed at the bottom of the top plate 2, with the length direction of each brush perpendicular to the length direction of the top plate 2. The top plate 2 simulates the shield shell of a tunnel boring machine, and the base plate 3 simulates the tunnel segments in a stationary state. The vertical movement of the base plate 3 adjusts the distance between the base plate 3 and the top plate 2, simulating different tail shield gaps during operation. The vertical movement of the base plate 3 can be achieved by using existing hydraulic cylinders, telescopic arms, or other drive mechanisms to adjust its height.

[0016] A grease injection valve 5 is installed on the upper part of the top plate 2 between adjacent tail brushes 4. The grease injection valve 5 is connected to a grease injection pump through a pipeline. Side plates 6 are provided on both sides of the top plate 2 and bottom plate 3 along their length, and a front plate 7 is provided at one end of the top plate 2 and bottom plate 3 along their length. The top plate 2, bottom plate 3, tail brushes 4, and side plates 6 form a relatively closed sealing cavity 8, and the grease injection valve 5 is connected to the sealing cavity 8. The grease injection valve 5 is used to monitor the grease injection pressure and control the grease injection switch. The tail sealing grease is injected into the sealing cavity 8 by the grease injection pump to simulate the construction environment.

[0017] The top plate 2, bottom plate 3, tail brush 4, and front plate 7 form a relatively enclosed pressure chamber 9. A pressure valve 10 connected to the pressure chamber 9 is installed on the top plate 2. The pressure valve 10 is connected to a pressure pump via a pipeline and is used to inject water or grout into the pressure chamber 9 to simulate the pressure environment of the tail shield. A pressure relief hole and a pressure relief valve connected to the pressure chamber 9 can also be provided on one side of the pressure valve 10 for internal pressure relief operations after the test.

[0018] A sliding plate 11 that can move along the length direction is also provided on the base plate 3. The sliding plate 11 can move closer to the front plate 7. The relatively moving sliding plate 11 is used to simulate the movement of the tunnel boring machine relative to the tunnel segments. By controlling the moving speed of the sliding plate 11, different tunneling rates under working conditions can be simulated. The movement of the sliding plate 11 can be achieved by existing power mechanisms such as motors and drive cylinders.

[0019] Pressure sensors 12 and temperature sensors 13 are also installed at the bottom of the top plate 2 corresponding to the positions of pressure chamber 9 and each sealing chamber 8. These sensors monitor the real-time pressure and temperature values ​​within the pressure chamber 9 and each sealing chamber 8 to determine whether grease leakage has occurred by monitoring changes in these values. Pressure sensors 12 and temperature sensors 13 are connected to the main control system via control circuitry. The main control system can be an existing PLC, microcontroller, or other control device.

[0020] Furthermore, to more accurately simulate the shield shell of a large-diameter tunnel boring machine, both the top plate 2 and the bottom plate 3 are arc plates, with the curvature of the top plate 2 itself being one-twelfth the diameter of a circle of 15 meters. To facilitate the installation of the tail brushes 4 at different positions on the top plate 2, the spacing of each row of tail brushes 4 is adjusted by changing their installation positions to simulate different tail brush spacings during construction. Several rows of bolt holes 14 are provided on the top plate 2, and connecting bolts 15 that mate with the bolt holes 14 are installed on the tail brushes 4. When the connecting bolts 15 are connected to the bolt holes 14 at different positions, the spacing between the tail brushes 4 can be adjusted to simulate different construction conditions. The installation of the tail brushes 4 at different positions does not affect the monitoring functions of the pressure sensor 12 and the temperature sensor 13.

[0021] In order to prevent deformation of the top plate 2 due to reaction force during grease injection and pressurization, and to further increase the strength of the top plate 2 itself, a number of reinforcing plates 16 arranged along the width direction are also provided on the top plate 2.

[0022] The side plate 6 and the front plate 7 are located between the top plate 2 and the bottom plate 3, forming a relatively enclosed space. In order to accommodate shield tail gaps of different heights, the side plate 6 and the front plate 7 also have different specifications of corresponding heights. After the vertical height position of the bottom plate 3 relative to the top plate 2 is adjusted, the top plate 2 and the bottom plate 3 are fixedly installed at the corresponding positions. In order to ensure the sealing performance of the sealing cavity 8 and the pressure cavity 9, a first sealing ring 17 is installed on the inner circumferential surface of the side plate 6, and a second sealing ring 18 is installed on the inner circumferential surface of the front plate 7.

[0023] Furthermore, to achieve vertical lifting and lowering adjustment of the base plate 3 relative to the top plate 2 on the reaction frame 1, a jack 19 is installed on the reaction frame 1, and a lifting platform 20 is installed on the telescopic rod of the jack 19. A support frame 21 is provided at the bottom of the base plate 3, and the support frame 21 is located on the lifting platform 20. By controlling the extension and retraction of the jack 19, the base plate 3 can be vertically lifted and lowered relative to the top plate 2, thereby achieving the adjustment of the shield tail gap.

[0024] Furthermore, in order to achieve the movement drive of the sliding plate 11, such as Figure 10As shown, the reaction frame 1 has a vertically arranged vertical displacement cylinder 22 at the end away from the front plate 7. A lifting seat 23 is mounted on the piston rod of the vertical displacement cylinder 22, and a horizontally arranged electric push rod 24 is mounted on the lifting seat 23. A hinge seat 25 is mounted on the end of the sliding plate 11, and a hinge shaft 26 that cooperates with the hinge seat 25 is provided at the end of the piston rod of the electric push rod 24. The vertical displacement cylinder 22 can be linked with the jack 19 to ensure that the height position of the electric push rod 24 is consistent with that of the sliding plate 11, and the height position of the electric push rod 24 can be adjusted according to the simulated working conditions of different shield tail gaps.

[0025] When the electric push rod 24 moves vertically to the same horizontal position as the sliding plate 11, the extension and retraction of the piston rod of the electric push rod 24 can drive the sliding plate 11 to move along the length of the base plate 3. By controlling the extension and retraction rate of the piston rod on the electric push rod 24, the tunneling rate under different working conditions can be simulated.

[0026] The method for conducting tests under standard operating conditions using the shield tail sealing simulation test device described in this invention includes the following steps: ① Adjusting the height of the base plate 3 to maximize the distance between the top plate 2 and the base plate 3, facilitating the subsequent installation of the shield tail brush 4, and moving the sliding plate 11 to an initial position away from the front plate 7 between the base plate 3 and the top plate 2; ② Installing 2-4 shield tail brushes 4 at a set position at the bottom of the top plate 2, with a spacing of 400-550mm between adjacent shield tail brushes 4, forming 1-3 sealing cavities 8; ③ Coating each sealing cavity 8 and the shield tail brush 4 with hand-applied shield tail sealing grease; ④ Adjusting the height of the base plate 3... Position the top plate 2 and bottom plate 3 such that the distance between them is 40-110mm. Then, install the side plate 6 and front plate 7 between the top plate 2 and bottom plate 3 to form a closed sealing cavity 8 and a pressure cavity 9 between them. ⑤ Install a 5-25m grease injection pipe on the grease injection valve 5 and connect it to the grease injection pump. Open the grease injection valve 5 and the grease injection pump, adjust the grease injection pump pressure to 10-50 bar, and inject pump-type shield tail sealing grease into the sealing cavity 8. Adjust the grease injection valve 5 so that the pressure in each sealing cavity 8 is 0.5-4.0MPa. ⑥ Install a pressure pipe on the pressure valve 10 and connect it to the pressure pump. Open the pressure valve 10. The pressure pump is set to a pressure of 0.5-4.0 MPa. Water or grout is injected into the pressure chamber 9. The readings of pressure sensor 12 are observed and recorded. The pressure fluctuation is recorded within 10 minutes. If the pressure fluctuation is less than 15%, the static seal is good. If the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation is greater than 25%, the seal is considered to have failed. At the same time, the leakage of sealing grease at the tail end of the device is observed. If the seepage is an intact grease sample, it is recorded as sample seepage. If the seepage is a water-oil mixture, it is recorded as mixed seepage. ⑦ The moving speed of sliding plate 11 is set to 1-12. mm / s, the sliding plate 11 moves closer to the front plate 7 along the length of the base plate 3, and records the fluctuation of the pressure sensor 12 reading. If the pressure fluctuation is less than 15%, the dynamic seal is good. If the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the exudate is an intact grease sample, it is recorded as sample leakage. If the exudate is a water-oil mixture, it is recorded as mixed leakage. ⑧ Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

[0027] The method for conducting tests using the shield tail sealing simulation test device described in this invention under synchronous grouting conditions includes the following steps: ① Adjusting the height of the base plate 3 to maximize the distance between the top plate 2 and the base plate 3, facilitating the subsequent installation of the shield tail brush 4, and moving the sliding plate 11 to an initial position away from the front plate 7 between the base plate 3 and the top plate 2; ② Installing 2-4 shield tail brushes 4 at a set position at the bottom of the top plate 2, with a spacing of 400-550mm between adjacent shield tail brushes 4, forming 1-3 sealing cavities 8; ③ Adjusting the height of the base plate 3 to make the distance between the top plate 2 and the base plate 3 40-110mm, and then... Install side plates 6 and front plates 7 between the top plate 2 and the bottom plate 3 to form a closed sealing cavity 8 and a pressure cavity 9 between the top plate 2 and the bottom plate 3; ④ Install a 5-25m grease injection pipe on the grease injection valve 5 and connect it to the grease injection pump, install a pressure pipe on the pressure valve 10 and connect it to the pressure pump, open the grease injection valve 5 and the grease injection pump, adjust the pressure of the grease injection pump to 10-50 bar, inject pump-type shield tail sealing grease into the sealing cavity 8, and after the sealing cavity 8 is full of grease and the pressure sensor 12 reading reaches 0.5MPa, open the pressure pump and set the pressure to 0.5-4.0MPa, inject water or grout into the pressure cavity 9, and always maintain The pressure in the sealing chamber 8 is 0.5 MPa greater than the pressure in the pressure chamber 9; ⑤ After the pressure in the pressure chamber 9 reaches the set value, observe and record the reading of the pressure sensor 12, and record the pressure fluctuation within 10 minutes. If the pressure fluctuation is less than 15%, the static seal is good; if the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified; if the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as sample seepage; if the seepage is a water-oil mixture, it is recorded as mixed seepage; ⑥ Set the moving speed of the sliding plate 11. The rate is 1-12 mm / s. The sliding plate 11 moves close to the front plate 7 along the length of the base plate 3 and records the fluctuation of the pressure sensor 12 reading. If the pressure fluctuation amplitude is less than 15%, the dynamic seal is good. If the pressure fluctuation amplitude is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation amplitude is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as sample seepage. If the seepage is a water-oil mixture, it is recorded as mixed seepage. ⑦ Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

[0028] The method for conducting tests using the shield tail sealing simulation test device of the present invention under simulated working conditions of up and down shield tunneling includes the following steps: ① Adjusting the height of the base plate 3 to maximize the distance between the top plate 2 and the base plate 3, so as to facilitate the subsequent installation of the shield tail brush 4, and moving the sliding plate 11 to an initial position away from the front plate 7 between the base plate 3 and the top plate 2; ② Installing 2-4 shield tail brushes 4 at a set position at the bottom of the top plate 2, with a spacing of 400-550mm between adjacent shield tail brushes 4, forming 1-3 sealing cavities 8; ③ Applying hand-applied shield tail sealing grease to each sealing cavity 8 and the shield tail brush 4; ④ Adjusting the base plate The height position of plate 3 is such that the distance between the front end of top plate 2 and the front end of bottom plate 3 is 40-110mm, and the distance between the rear end of top plate 2 and the rear end of bottom plate 3 is 40-110mm, so that the slope of bottom plate 3 is 0-2.0%. Then, side plate 6 and front plate 7 are installed between top plate 2 and bottom plate 3, so that a closed sealing cavity 8 and pressure cavity 9 are formed between top plate 2 and bottom plate 3; ⑤ Install a 5-25m grease injection pipe on grease injection valve 5 and connect it to grease injection pump. Open grease injection valve 5 and grease injection pump, adjust grease injection pump pressure to 10-50 bar, inject pump-type shield tail sealing grease into sealing cavity 8, and adjust grease injection valve 5 so that each The pressure in sealing chamber 8 is 0.5-4.0 MPa; ⑥ Install a pressure pipe on the pressure valve 10 and connect it to the pressure pump. Turn on the pressure pump and set the pressure to 0.5-4.0 MPa. Inject water or grout into pressure chamber 9, observe and record the reading of pressure sensor 12, and record the pressure fluctuation within 10 minutes. If the pressure fluctuation is less than 15%, the static seal is good. If the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as a sample. Leakage is recorded as mixed leakage if the exudate is a mixture of water and oil; ⑦ Set the moving speed of the sliding plate 11 to 1-12 mm / s. The sliding plate 11 moves close to the front plate 7 along the length of the base plate 3, and record the fluctuation of the pressure sensor 12 reading. If the pressure fluctuation is less than 15%, the dynamic seal is good; if the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified; if the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the exudate is a complete grease sample, it is recorded as sample leakage; if the exudate is a mixture of water and oil, it is recorded as mixed leakage. The slope of the base plate 3 relative to the horizontal plane of the overall device is 0-2.0%; ⑧ Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

[0029] The method for conducting tests using the shield tail sealing simulation test device of the present invention under the simulated working conditions of synchronous grouting and upward and downward shield attitude includes the following steps: ① Adjusting the height position of the bottom plate 3 to maximize the distance between the top plate 2 and the bottom plate 3, so as to facilitate the subsequent installation of the shield tail brush 4, and moving the sliding plate 11 to an initial position away from the front plate 7 between the bottom plate 3 and the top plate 2; ② Installing 2-4 shield tail brushes 4 at a set position at the bottom of the top plate 2, with a spacing of 400-550mm between adjacent shield tail brushes 4, forming 1-3 sealing cavities 8; ③ Adjusting the height position of the bottom plate 3 to maximize the distance between the front end of the top plate 2 and the front end of the bottom plate 3. The distance between the rear end of the top plate 2 and the rear end of the bottom plate 3 is 40-110mm, making the slope of the bottom plate 3 0-2.0%. Then, the side plate 6 and the front plate 7 are installed between the top plate 2 and the bottom plate 3, forming a closed sealing cavity 8 and a pressure cavity 9 between the top plate 2 and the bottom plate 3; ④ Install a 5-25m grease injection pipe on the grease injection valve 5 and connect it to the grease injection pump. Install a pressure pipe on the pressure valve 10 and connect it to the pressure pump. Open the grease injection valve 5 and the grease injection pump, adjust the pressure of the grease injection pump to 10-50 bar, and inject pump-type shield tail sealing grease into the sealing cavity 8. Wait until the sealing cavity 8 is full of grease and the pressure sensor 12 reading reaches 0. After reaching 0.5 MPa, turn on the pressure pump and set the pressure to 0.5-4.0 MPa. Inject water or grout into pressure chamber 9, and always maintain the pressure in sealing chamber 8 0.5 MPa higher than the pressure in pressure chamber 9. ⑤ After the pressure in pressure chamber 9 reaches the set value, observe and record the reading of pressure sensor 12. Record the pressure fluctuation within 10 minutes. If the pressure fluctuation is less than 15%, the static seal is good. If the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample... If the substance is a sample, it is recorded as sample leakage; if the leakage is a mixture of water and oil, it is recorded as mixed leakage. ⑥ Set the moving speed of the sliding plate 11 to 1-12 mm / s. The sliding plate 11 moves closer to the front plate 7 along the length of the base plate 3, and record the fluctuation of the pressure sensor 12 reading. If the pressure fluctuation is less than 15%, the dynamic seal is good; if the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified; if the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the leakage is a complete grease sample, it is recorded as sample leakage; if the leakage is a mixture of water and oil, it is recorded as mixed leakage. The slope of the base plate 3 relative to the horizontal plane of the overall device is 0-2.0%. ⑦ Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

[0030] The following examples illustrate the various test methods: Example 1 under standard operating conditions: Step ①: Adjust the height of the base plate 3 to maximize the distance between the top plate 2 and the base plate 3. By fixing and installing 3 shield tail brushes 4 at the bottom of the top plate 2, 2 sealing cavities 8 are formed, and the distance between adjacent shield tail brushes 4 is 450mm. Step 2: Apply hand-applied shield tail sealing grease between each shield tail brush 4, and adjust the sliding plate 11 to move and reset away from the front plate 7. Step 3: Adjust the height of the base plate 3 so that the distance between the top plate 2 and the base plate 3 is 40mm. Then install the side plate 6 and the front plate 7 between the top plate 2 and the base plate 3 to form a closed sealing cavity 8 and a pressure cavity 9 between the top plate 2 and the base plate 3. Step 4: Install a 15m grease injection tube on the grease injection valve 5 and connect it to the grease injection pump to simulate long-distance pumping. Adjust the grease injection pump pressure to 20 bar. Adjust the grease injection valve 5 connected to the first sealing cavity 8 so that the reading of the pressure sensor 12 in the first sealing cavity 8 is 1.5 MPa. Adjust the grease injection valve 5 connected to the second sealing cavity 8 so that the reading of the pressure sensor 12 in the second sealing cavity 8 is 1.0 MPa. Step 5: Turn on the pressure pump and inject water into the pressure chamber 9 so that the pressure in the pressure chamber 9 reaches 1.0MPa. Observe the reading of the pressure sensor 12, record the pressure fluctuation in the sealing chamber 8, and observe the leakage of the tail shield sealing grease. Step 6: Adjust the moving speed of the sliding plate 11 to 5 mm / s and move it close to the front plate 7 to simulate shield tunneling construction and observe the fluctuation of the pressure sensor 12 reading and the leakage of the tail sealing grease under dynamic conditions. Step 7: Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

[0031] Example 2 under standard operating conditions: Step ①: Adjust the height of the base plate 3 to maximize the distance between the top plate 2 and the base plate 3. By fixing and installing 4 shield tail brushes 4 at the bottom of the top plate 2, 3 sealing cavities 8 are formed, and the distance between adjacent shield tail brushes 4 is 500mm. Step 2: Apply hand-applied shield tail sealing grease between each shield tail brush 4, and adjust the sliding plate 11 to move and reset away from the front plate 7. Step 3: Adjust the height of the base plate 3 so that the distance between the top plate 2 and the base plate 3 is 70mm. Then install the side plate 6 and the front plate 7 between the top plate 2 and the base plate 3 to form a closed sealing cavity 8 and a pressure cavity 9 between the top plate 2 and the base plate 3. Step 4: Install a 20m grease injection tube on the grease injection valve 5 and connect it to the grease injection pump to simulate long-distance pumping. Adjust the grease injection pump pressure to 35 bar. Adjust the grease injection valve 5 connected to the first sealing chamber 8 so that the reading of the pressure sensor 12 in the first sealing chamber 8 is 3.0 MPa. Adjust the grease injection valve 5 connected to the second sealing chamber 8 so that the reading of the pressure sensor 12 in the second sealing chamber 8 is 2.5 MPa. Adjust the grease injection valve 5 connected to the third sealing chamber 8 so that the reading of the pressure sensor 12 in the third sealing chamber 8 is 1.5 MPa. Step 5: Turn on the pressure pump and inject water into the pressure chamber 9 so that the pressure in the pressure chamber 9 reaches 2.5MPa. Observe the reading of the pressure sensor 12, record the pressure fluctuation in the sealing chamber 8, and observe the leakage of the tail shield sealing grease. Step 6: Adjust the moving speed of the sliding plate 11 to 3 mm / s and move it close to the front plate 7 to simulate shield tunneling construction and observe the fluctuation of the pressure sensor 12 reading and the leakage of the tail sealing grease under dynamic conditions. Step 7: Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

[0032] Example 3 under synchronous grouting conditions: Step ①: Adjust the height of the base plate 3 to maximize the distance between the top plate 2 and the base plate 3. By fixing and installing 4 shield tail brushes 4 at the bottom of the top plate 2, 3 sealing cavities 8 are formed, and the distance between adjacent shield tail brushes 4 is 500mm. Step 2: Apply hand-applied shield tail sealing grease between each shield tail brush 4, and adjust the sliding plate 11 to move and reset away from the front plate 7. Step 3: Adjust the height of the base plate 3 so that the distance between the top plate 2 and the base plate 3 is 50mm. Then install the side plate 6 and the front plate 7 between the top plate 2 and the base plate 3 to form a closed sealing cavity 8 and a pressure cavity 9 between the top plate 2 and the base plate 3. Step 4: Install a 20m grease injection pipe on the grease injection valve 5 and connect it to the grease injection pump to simulate long-distance pumping. Adjust the grease injection pump pressure to 35 bar, open the grease injection valve 5, and when the pressure sensor 12 in the sealing cavity 8 reaches 0.5 MPa, adjust the pressure pump to inject grout into the pressure cavity 9, keeping the pressure in the sealing cavity 8 always 0.5 MPa higher than the pressure in the pressure cavity 9, until the pressure sensor 12 in the sealing cavity 8 reaches 3.0 MPa, simulating synchronous grease injection and grouting. Step 5: Observe the reading of pressure sensor 12, record the pressure fluctuation in the sealing cavity 8, and observe the leakage of the tail shield sealing grease; Step 6: Adjust the moving speed of the sliding plate 11 to 2 mm / s and move it close to the front plate 7 to simulate shield tunneling construction and observe the fluctuation of the pressure sensor 12 reading and the leakage of the tail sealing grease under dynamic conditions. Step 7: Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

[0033] Example 4 under synchronous grouting conditions: Step ①: Adjust the height of the base plate 3 to maximize the distance between the top plate 2 and the base plate 3. By fixing two shield tail brushes 4 at the bottom of the top plate 2, a sealed cavity 8 is formed, and the distance between adjacent shield tail brushes 4 is 450mm. Step 2: Adjust the sliding plate 11 to move and reset to the end away from the front plate 7; Step 3: Adjust the height of the base plate 3 so that the distance between the top plate 2 and the base plate 3 is 60mm. Then install the side plate 6 and the front plate 7 between the top plate 2 and the base plate 3 to form a closed sealing cavity 8 and a pressure cavity 9 between the top plate 2 and the base plate 3. Step 4: Install a 10m grease injection pipe on the grease injection valve 5 and connect it to the grease injection pump. Adjust the grease injection pump pressure to 25 bar, open the grease injection valve 5, and when the pressure sensor 12 in the sealing cavity 8 reaches 0.5 MPa, adjust the pressure pump to inject grout into the pressure cavity 9, keeping the pressure in the sealing cavity 8 always 0.5 MPa higher than the pressure in the pressure cavity 9, until the pressure sensor 12 in the sealing cavity 8 reaches 2.0 MPa, simulating synchronous grease injection and grouting. Step 5: Observe the reading of pressure sensor 12, record the pressure fluctuation in the sealing cavity 8, and observe the leakage of the tail shield sealing grease; Step 6: Adjust the moving speed of the sliding plate 11 to 10 mm / s and move it close to the front plate 7 to simulate shield tunneling construction and observe the fluctuation of the pressure sensor 12 reading and the leakage of the tail sealing grease under dynamic conditions. Step 7: Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

[0034] Example 5: Simulated working condition of synchronous grouting and upward shield attitude: Step ①: Adjust the height of the base plate 3 to maximize the distance between the top plate 2 and the base plate 3. By fixing and installing 4 shield tail brushes 4 at the bottom of the top plate 2, 3 sealing cavities 8 are formed, and the distance between adjacent shield tail brushes 4 is 400mm. Step 2: Adjust the sliding plate 11 to move and reset to the end away from the front plate 7; Step 3: Adjust the height of the bottom plate 3 so that the distance between the front end of the top plate 2 and the front end of the bottom plate 3 is 50mm and the distance between the rear end of the top plate 2 and the rear end of the bottom plate 3 is 60mm, simulating the upward tunneling posture. Then, install the side plate 6 and the front plate 7 between the top plate 2 and the bottom plate 3 to form a closed sealing cavity 8 and a pressure cavity 9 between the top plate 2 and the bottom plate 3. Step 4: Install a 15m grease injection pipe on the grease injection valve 5 and connect it to the grease injection pump. Adjust the grease injection pump pressure to 25 bar, open the grease injection valve 5, and when the pressure sensor 12 in the sealing cavity 8 reaches 0.5 MPa, adjust the pressure pump to inject grout into the pressure cavity 9, keeping the pressure in the sealing cavity 8 always 0.5 MPa higher than the pressure in the pressure cavity 9, until the pressure sensor 12 in the sealing cavity 8 reaches 2.0 MPa, simulating synchronous grease injection and grouting. Step 5: Observe the reading of pressure sensor 12, record the pressure fluctuation in the sealing cavity 8, and observe the leakage of the tail shield sealing grease; Step 6: Adjust the moving speed of the sliding plate 11 to 3 mm / s and move it close to the front plate 7 to simulate shield tunneling construction and observe the fluctuation of the pressure sensor 12 reading and the leakage of the tail sealing grease under dynamic conditions. Step 7: Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

[0035] Example 6: Simulation of the attitude of the descending shield tunneling machine Step ①: Adjust the height of the base plate 3 to maximize the distance between the top plate 2 and the base plate 3. By fixing and installing 4 shield tail brushes 4 at the bottom of the top plate 2, 3 sealing cavities 8 are formed, and the distance between adjacent shield tail brushes 4 is 450mm. Step 2: Apply hand-applied shield tail sealing grease between each shield tail brush 4, and adjust the sliding plate 11 to move and reset away from the front plate 7. Step 3: Adjust the height of the bottom plate 3 so that the distance between the front end of the top plate 2 and the front end of the bottom plate 3 is 100mm and the distance between the rear end of the top plate 2 and the rear end of the bottom plate 3 is 80mm to simulate the downward tunneling posture. Then, install the side plate 6 and the front plate 7 between the top plate 2 and the bottom plate 3 to form a closed sealing cavity 8 and a pressure cavity 9 between the top plate 2 and the bottom plate 3. Step 4: Install a 15m grease injection tube on the grease injection valve 5 and connect it to the grease injection pump to simulate long-distance pumping. Adjust the grease injection pump pressure to 35 bar. Adjust the grease injection valve 5 connected to the first sealing cavity 8 so that the reading of the pressure sensor 12 in the first sealing cavity 8 is 3.0 MPa. Adjust the grease injection valve 5 connected to the second sealing cavity 8 so that the reading of the pressure sensor 12 in the second sealing cavity 8 is 2.5 MPa. Adjust the grease injection valve 5 connected to the third sealing cavity 8 so that the reading of the pressure sensor 12 in the third sealing cavity 8 is 1.5 MPa. Step 5: Turn on the pressure pump and inject water into the pressure chamber 9 so that the pressure in the pressure chamber 9 reaches 2.5MPa. Observe the reading of the pressure sensor 12, record the pressure fluctuation in the sealing chamber 8, and observe the leakage of the tail shield sealing grease. Step 6: Adjust the moving speed of the sliding plate 11 to 5 mm / s and move it close to the front plate 7 to simulate shield tunneling construction and observe the fluctuation of the pressure sensor 12 reading and the leakage of the tail sealing grease under dynamic conditions. Step 7: Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

[0036] Furthermore, the test device can collect and learn historical test data based on the LSTM neural network on the main control system, complete the prediction of the sealing cavity pressure in the next 3-25 seconds, and provide the optimal grease injection pressure for different working conditions by combining the corresponding sealing effect evaluation method. The main control system is an external computer. The historical test data includes pressure chamber pressure, sealing chamber pressure, tail shield brush spacing, tail shield gap, tunneling inclination angle, tunneling speed, grease injection pressure, and temperature. The pressure chamber pressure and sealing chamber pressure are acquired by pressure sensors, and the temperature is acquired by temperature sensors. The tail shield brush spacing, tail shield gap, tunneling inclination angle, tunneling speed, and grease injection pressure are manually input. The pressure and temperature sensors may also have wireless transmission capabilities for connecting to the main control system and transmitting data. For an LSTM neural network, the data sampling period Δt is 0.1-0.5s. At any given time, the observation vector includes the pressure in the pressure chamber P. e (t), sealing cavity pressure: P s1 (t), P s2 (t), P s3 (t) (average of two pressure sensors for each chamber), temperature T s1 (t), T s3 (t), shield tail clearance g(t), sliding plate speed (tunneling speed) v(t), historical grease injection pressure setting value P injs1 (t-Δt), P injs2 (t-Δt), P injs3 (t-Δt). Construct a sliding time window of length L=30-50 (corresponding to data from the past 3-25 seconds): W t = {O[t-L+1], O[t-L+2], ..., Ot} Among them W t The dimension is L×N f N fThis is the dimension of Ot, which is the basic input of the LSTM model. The model predicts the sealing state in the next H steps (H=30-50, corresponding to the next 3-25 seconds) based on the input data and historical experimental data learned. The pressure of each sealing cavity in the future is denoted as P. si (t+1), ..., P si (t+H); The future sealing condition is evaluated using predicted sealing cavity pressure data. The method for evaluating the sealing effect is as follows: Intercavity pressure gradient: Grad ij (t)=|P si (t) - P sj (t)| / d ij , Where d ij P is the distance between sealed cavities i and j. si (t) is the algorithm-predicted pressure of the i-th sealing cavity at time t, P sj (t) is the algorithm-predicted pressure of the j-th sealing cavity at time t. The intercavity pressure gradient is used to provide technicians with a reference for predicting the sealing effect. Pressure maintenance rate: R si (t+k|t) = P si (t+k) / P e (t), Where P si (t+k) is the algorithm-predicted pressure of the i-th sealing cavity at time t+k, P e (t) is the observed pressure in the pressure chamber at time t. The ideal pressure maintenance rate should be slightly greater than 1 to form a positive seal, providing technicians with a reference for predicting the sealing effect. Leakage risk index: LR(t) = α × Sigmoid{β × P e (t)-β×min[P s (t)]}+γ×Sigmoid{δ×[|v(t)|]} Among them, P e (t) represents the observed pressure in the pressure chamber at time t, min[P s [(t)] is the predicted minimum pressure at time t among the three sealed cavities. α , β , γ , δ For adjustable weight parameters, α The value range is 0.4 to 0.6. β The value range is 0.8 to 1.2. γ The value range is 0.3 to 0.5. δ The range is 0.05~0.15, and the closer LR is to 1, the higher the risk of leakage; The optimal injection pressure decision method is as follows: If LR < 0.3, then the optimal injection pressure is the current injection pressure plus or minus 0.2 bar. If 0.3 ≤ LR < 0.6, then the optimal injection pressure is the current injection pressure plus 0.5 bar to 1.0 bar. If 0.6 ≤ LR < 0.8, then the optimal injection pressure is the current injection pressure plus 1.0 bar to 2.0 bar. If LR≥0.8, the optimal grease injection pressure is the current grease injection pressure plus 2.0 to 3.0 bar.

[0037] The shield tail seal simulation test device and method described in this invention, through comprehensive performance testing of the shield tail sealing grease under different working conditions, can detect potential sealing problems, such as seal failure and grease leakage, before engineering construction. This provides important basis for engineering technicians to adjust construction plans in a timely manner and replace the shield tail sealing grease with appropriate ones, effectively avoiding engineering accidents caused by shield tail seal problems and ensuring the safe progress of engineering construction.

[0038] The shield tail seal simulation test device features a rational overall structural design, with convenient installation and adjustment of each component, allowing operators to easily complete the test preparation and operation process. For example, operations such as adjusting the base plate height, installing the shield tail brush, and moving the sliding plate are designed to be relatively simple, improving test efficiency and reducing human error. Furthermore, this device and method are not only applicable to shield tail seal testing of different specifications of tunnel boring machines (TBMs), but can also flexibly adjust test parameters and operating conditions according to the specific needs of different engineering projects, demonstrating strong versatility and adaptability. Whether it's urban subway tunnels, water conservancy tunnels, or other types of TBM projects, this device and method can be used to test the performance of shield tail sealing grease and optimize construction parameters.

[0039] The technical solutions of this invention are not limited to the embodiments described herein. All technical contents not described in detail herein are well-known technologies.

Claims

1. A shield tail sealing simulation test device, characterized in that: The test mechanism includes a reaction frame (1) and a test mechanism installed inside the reaction frame (1). The test mechanism includes a top plate (2) fixed on the reaction frame (1). The bottom of the top plate (2) is provided with a bottom plate (3) that can be raised and lowered vertically. Several rows of shield tail brushes (4) are installed at the bottom of the top plate (2). The length direction of each shield tail brush (4) is perpendicular to the length direction of the top plate (2). A grease injection valve (5) is installed on the upper part of the top plate (2) between adjacent shield tail brushes (4). Side plates (6) are provided on both sides of the length direction of the top plate (2) and the bottom plate (3). A front plate (7) is provided at one end of the length direction of the top plate (2) and the bottom plate (3). The top plate (2), the bottom plate (3), the shield tail brushes (4) and the side plates (6) are arranged in a manner that allows for vertical lifting and lowering. A relatively closed sealed cavity (8) is formed between the top plate (2), bottom plate (3), shield tail brush (4) and front plate (7). A relatively closed pressure cavity (9) is formed between the top plate (2), bottom plate (3), shield tail brush (4) and front plate (7). A pressure valve (10) connected to the pressure cavity (9) is installed on the top plate (2). A sliding plate (11) that can move along the length direction is also provided on the bottom plate (3). The sliding plate (11) can move close to the front plate (7). A pressure sensor (12) and a temperature sensor (13) are also installed at the bottom of the top plate (2) corresponding to the positions of the pressure cavity (9) and each sealed cavity (8). The pressure sensor (12) and the temperature sensor (13) are connected to the main control system through control lines.

2. The shield tail sealing simulation test device according to claim 1, characterized in that: The top plate (2) and the bottom plate (3) are both arc plates. Several rows of bolt holes (14) are provided on the top plate (2). Connecting bolts (15) that cooperate with the bolt holes (14) are installed on the shield tail brush (4). Several reinforcing plates (16) arranged along the width direction are also provided on the top plate (2).

3. The shield tail sealing simulation test device according to claim 1, characterized in that: A first sealing ring (17) is installed on the inner circumferential surface of the side plate (6), and a second sealing ring (18) is installed on the inner circumferential surface of the front plate (7).

4. The shield tail sealing simulation test device according to claim 1, characterized in that: A jack (19) is installed on the reaction frame (1), and a lifting platform (20) is installed on the telescopic rod of the jack (19). A support frame (21) is provided at the bottom of the base plate (3), and the support frame (21) is located on the lifting platform (20).

5. The shield tail sealing simulation test device according to claim 1, characterized in that: The reaction frame (1) is provided with a vertically arranged vertical moving cylinder (22) at one end away from the front plate (7). A lifting seat (23) is installed on the piston rod of the vertical moving cylinder (22). A horizontally arranged electric push rod (24) is provided on the lifting seat (23). A hinge seat (25) is installed at the end of the sliding plate (11). A hinge shaft (26) that cooperates with the hinge seat (25) is provided at the end of the piston rod of the electric push rod (24). After the electric push rod (24) moves vertically to the same horizontal position as the sliding plate (11), the extension and retraction of the piston rod of the electric push rod (24) can drive the sliding plate (11) to move along the length direction of the bottom plate (3).

6. A method for conducting tests under standard operating conditions using the shield tail seal simulation test device described in claim 1, characterized in that: It includes the following steps: ① Adjust the height of the bottom plate (3) to maximize the distance between the top plate (2) and the bottom plate (3) so that the shield tail brush (4) can be installed later, and move the sliding plate (11) to the initial position between the bottom plate (3) and the top plate (2) away from the front plate (7); ② Install 2-4 shield tail brushes (4) at the set position at the bottom of the top plate (2), with a spacing of 400-550mm between adjacent shield tail brushes (4) to form 1-3 sealing cavities (8). ③ Apply hand-applied shield tail sealing grease to each sealing cavity (8) and shield tail brush (4); ④ Adjust the height of the bottom plate (3) so that the distance between the top plate (2) and the bottom plate (3) is 40-110mm. Then install the side plate (6) and the front plate (7) between the top plate (2) and the bottom plate (3) to form a closed sealing cavity (8) and a pressure cavity (9) between the top plate (2) and the bottom plate (3). ⑤ Install a 5-25m grease injection pipe on the grease injection valve (5) and connect it to the grease injection pump. Open the grease injection valve (5) and the grease injection pump. Adjust the pressure of the grease injection pump to 10-50 bar and inject pump-type shield tail sealing grease into the sealing cavity (8). Adjust the grease injection valve (5) so that the pressure of each sealing cavity (8) is 0.5-4.0 MPa. ⑥ Install a pressure pipe on the pressure valve (10) and connect it to the pressure pump. Turn on the pressure pump and set the pressure to 0.5-4.0 MPa. Inject water or grout into the pressure chamber (9), observe and record the reading of the pressure sensor (12), and record the pressure fluctuation within 10 minutes. If the pressure fluctuation is less than 15%, the static seal is good. If the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the oozing material is an intact grease sample, it is recorded as sample leakage. If the oozing material is a water-oil mixture, it is recorded as mixed leakage. ⑦ Set the moving speed of the sliding plate (11) to 1-12 mm / s. The sliding plate (11) moves close to the front plate (7) along the length direction of the bottom plate (3) and records the fluctuation of the reading of the pressure sensor (12). If the pressure fluctuation amplitude is less than 15%, the dynamic seal is good. If the pressure fluctuation amplitude is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation amplitude is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is a complete grease sample, it is recorded as sample seepage. If the seepage is a water-oil mixture, it is recorded as mixed seepage. ⑧ Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

7. A method for conducting tests using the shield tail seal simulation test device described in claim 1 under synchronous grouting conditions, characterized in that: It includes the following steps: ① Adjust the height of the bottom plate (3) to maximize the distance between the top plate (2) and the bottom plate (3) so that the shield tail brush (4) can be installed later, and move the sliding plate (11) to the initial position between the bottom plate (3) and the top plate (2) away from the front plate (7); ② Install 2-4 shield tail brushes (4) at the set position at the bottom of the top plate (2), with a spacing of 400-550mm between adjacent shield tail brushes (4) to form 1-3 sealing cavities (8). ③ Adjust the height of the bottom plate (3) so that the distance between the top plate (2) and the bottom plate (3) is 40-110mm. Then install the side plate (6) and the front plate (7) between the top plate (2) and the bottom plate (3) to form a closed sealing cavity (8) and a pressure cavity (9) between the top plate (2) and the bottom plate (3). ④ Install a 5-25m grease injection pipe on the grease injection valve (5) and connect it to the grease injection pump. Install a pressure pipe on the pressure valve (10) and connect it to the pressure pump. Open the grease injection valve (5) and the grease injection pump. Adjust the pressure of the grease injection pump to 10-50 bar. Inject pumpable shield tail sealing grease into the sealing cavity (8). After the sealing cavity (8) is filled with grease and the pressure sensor (12) reading reaches 0.5 MPa, open the pressure pump and set the pressure to 0.5-4.0 MPa. Inject water or grout into the pressure cavity (9) and always keep the pressure in the sealing cavity (8) 0.5 MPa greater than the pressure in the pressure cavity (9). ⑤ After the pressure in the pressure chamber (9) reaches the set value, observe and record the reading of the pressure sensor (12), and record the pressure fluctuation within 10 minutes. If the pressure fluctuation is less than 15%, the static seal is good. If the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as sample seepage. If the seepage is a water-oil mixture, it is recorded as mixed seepage. ⑥ Set the moving speed of the sliding plate (11) to 1-12 mm / s. The sliding plate (11) moves close to the front plate (7) along the length direction of the bottom plate (3) and records the fluctuation of the reading of the pressure sensor (12). If the pressure fluctuation amplitude is less than 15%, the dynamic seal is good. If the pressure fluctuation amplitude is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation amplitude is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as sample seepage. If the seepage is a water-oil mixture, it is recorded as mixed seepage. ⑦ Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

8. A method for conducting tests using the shield tail sealing simulation test device described in claim 1 under simulated upward and downward shield tunneling attitude conditions, characterized in that: It includes the following steps: ① Adjust the height of the bottom plate (3) to maximize the distance between the top plate (2) and the bottom plate (3) so that the shield tail brush (4) can be installed later, and move the sliding plate (11) to the initial position between the bottom plate (3) and the top plate (2) away from the front plate (7); ② Install 2-4 shield tail brushes (4) at the set position at the bottom of the top plate (2), with a spacing of 400-550mm between adjacent shield tail brushes (4) to form 1-3 sealing cavities (8). ③ Apply hand-applied shield tail sealing grease to each sealing cavity (8) and shield tail brush (4); ④ Adjust the height of the base plate (3) so that the distance between the front end of the top plate (2) and the front end of the base plate (3) is 40-110mm, and the distance between the rear end of the top plate (2) and the rear end of the base plate (3) is 40-110mm, so that the slope of the base plate (3) is 0-2.0%. Then install the side plate (6) and the front plate (7) between the top plate (2) and the base plate (3) to form a closed sealing cavity (8) and a pressure cavity (9) between the top plate (2) and the base plate (3). ⑤ Install a 5-25m grease injection pipe on the grease injection valve (5) and connect it to the grease injection pump. Open the grease injection valve (5) and the grease injection pump. Adjust the pressure of the grease injection pump to 10-50 bar and inject pump-type shield tail sealing grease into the sealing cavity (8). Adjust the grease injection valve (5) so that the pressure of each sealing cavity (8) is 0.5-4.0 MPa. ⑥ Install a pressure pipe on the pressure valve (10) and connect it to the pressure pump. Turn on the pressure pump and set the pressure to 0.5-4.0 MPa. Inject water or grout into the pressure chamber (9), observe and record the reading of the pressure sensor (12), and record the pressure fluctuation within 10 minutes. If the pressure fluctuation is less than 15%, the static seal is good. If the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the oozing material is an intact grease sample, it is recorded as sample leakage. If the oozing material is a water-oil mixture, it is recorded as mixed leakage. ⑦ Set the moving speed of the sliding plate (11) to 1-12 mm / s. The sliding plate (11) moves close to the front plate (7) along the length direction of the bottom plate (3) and records the fluctuation of the reading of the pressure sensor (12). If the pressure fluctuation amplitude is less than 15%, the dynamic seal is good. If the pressure fluctuation amplitude is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation amplitude is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is a complete grease sample, it is recorded as sample seepage. If the seepage is a water-oil mixture, it is recorded as mixed seepage. ⑧ Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

9. A method for conducting tests using the shield tail sealing simulation test device described in claim 1 under simulated conditions of synchronous grouting and upward and downward shield attitude, characterized in that: It includes the following steps: ① Adjust the height of the bottom plate (3) to maximize the distance between the top plate (2) and the bottom plate (3) so that the shield tail brush (4) can be installed later, and move the sliding plate (11) to the initial position between the bottom plate (3) and the top plate (2) away from the front plate (7); ② Install 2-4 shield tail brushes (4) at the set position at the bottom of the top plate (2), with a spacing of 400-550mm between adjacent shield tail brushes (4) to form 1-3 sealing cavities (8). ③ Adjust the height of the base plate (3) so that the distance between the front end of the top plate (2) and the front end of the base plate (3) is 40-110mm, and the distance between the rear end of the top plate (2) and the rear end of the base plate (3) is 40-110mm, so that the slope of the base plate (3) is 0-2.0%. Then install the side plate (6) and the front plate (7) between the top plate (2) and the base plate (3) to form a closed sealing cavity (8) and a pressure cavity (9) between the top plate (2) and the base plate (3). ④ Install a 5-25m grease injection pipe on the grease injection valve (5) and connect it to the grease injection pump. Install a pressure pipe on the pressure valve (10) and connect it to the pressure pump. Open the grease injection valve (5) and the grease injection pump. Adjust the pressure of the grease injection pump to 10-50 bar. Inject pumpable shield tail sealing grease into the sealing cavity (8). After the sealing cavity (8) is filled with grease and the pressure sensor (12) reading reaches 0.5 MPa, open the pressure pump and set the pressure to 0.5-4.0 MPa. Inject water or grout into the pressure cavity (9) and always keep the pressure in the sealing cavity (8) 0.5 MPa greater than the pressure in the pressure cavity (9). ⑤ After the pressure in the pressure chamber (9) reaches the set value, observe and record the reading of the pressure sensor (12), and record the pressure fluctuation within 10 minutes. If the pressure fluctuation is less than 15%, the static seal is good. If the pressure fluctuation is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as sample seepage. If the seepage is a water-oil mixture, it is recorded as mixed seepage. ⑥ Set the moving speed of the sliding plate (11) to 1-12 mm / s. The sliding plate (11) moves close to the front plate (7) along the length direction of the bottom plate (3) and records the fluctuation of the reading of the pressure sensor (12). If the pressure fluctuation amplitude is less than 15%, the dynamic seal is good. If the pressure fluctuation amplitude is greater than 15% but less than 25%, the static seal is qualified. If the pressure fluctuation amplitude is greater than 25%, it is judged as a seal failure. At the same time, observe the leakage of sealing grease at the tail of the device. If the seepage is an intact grease sample, it is recorded as sample seepage. If the seepage is a water-oil mixture, it is recorded as mixed seepage. ⑦ Start the LSTM neural network and seal effect evaluation calculation in the main control system to obtain the optimal grease injection pressure.

10. A method for conducting tests under simulated working conditions using any one of the shield tail sealing simulation test devices according to claims 6, 7, 8, and 9, characterized in that: The test device can collect and learn historical test data based on the LSTM neural network on the main control system, complete the prediction of the sealing cavity pressure in the next 3-25 seconds, and provide the optimal grease injection pressure for different working conditions by combining the corresponding sealing effect evaluation method. The main control system is an external computer. The historical test data includes pressure chamber pressure, sealing chamber pressure, shield tail brush spacing, shield tail gap, tunneling inclination angle, tunneling speed, grease injection pressure, and temperature. Among them, pressure chamber pressure and sealing chamber pressure are collected by pressure sensor (12), temperature is collected by temperature sensor (13), and shield tail brush spacing, shield tail gap, tunneling inclination angle, tunneling speed, and grease injection pressure are manually input. The LSTM neural network has a data sampling period Δt of 0.1-0.5s. At any given time, the observation vector includes the pressure P in the pressure chamber. e (t), sealing cavity pressure: P s1 (t), P s2 (t), P s3 (t) (average of two pressure sensors for each chamber), temperature T s1 (t), T s3 (t), shield tail clearance g(t), sliding plate speed (tunneling speed) v(t), historical grease injection pressure setting value P injs1 (t-Δt), P injs2 (t-Δt), P injs3 (t-Δt). Construct a sliding time window of length L=30-50 (corresponding to data from the past 3-25 seconds): W t = {O[t-L+1], O[t-L+2], ..., Ot} Among them W t The dimension is L×N f N f This is the dimension of Ot. This is the basic input to the LSTM model. The model predicts the sealing state in the next H steps (H=30-50, corresponding to the next 3-25 seconds) based on the input data and historical experimental data learned from it. The pressure of each sealing cavity in the future is denoted as P. si (t+1), ..., P si (t+H); The future sealing condition is evaluated using predicted sealing cavity pressure data. The method for evaluating the sealing effect is as follows: Intercavity pressure gradient: Grad ij (t)=|P si (t) - P sj (t)| / d ij , Where d ij P is the distance between sealed cavities i and j. si (t) is the algorithm-predicted pressure of the i-th sealing cavity at time t, P sj (t) is the algorithm-predicted pressure of the j-th sealing cavity at time t; Pressure maintenance rate: R si (t+k|t) = P si (t+k) / P e (t), Where P si (t+k) is the algorithm-predicted pressure of the i-th sealing cavity at time t+k, P e (t) is the observed pressure in the pressure chamber at time t; Leakage risk index: LR(t) = α × Sigmoid{β × P e (t)-β×min[P s (t)]}+γ×Sigmoid{δ× [|v(t)|]} Among them, P e (t) represents the observed pressure in the pressure chamber at time t, min[P s [(t)] is the predicted minimum pressure at time t among the three sealed cavities. α , β , γ , δ These are adjustable weight parameters. α The value range is 0.4 to 0.

6. β The value range is 0.8 to 1.

2. γ The value range is 0.3 to 0.

5. δ The range is 0.05~0.15; The optimal injection pressure decision method is as follows: If LR < 0.3, then the optimal injection pressure is the current injection pressure plus or minus 0.2 bar. If 0.3 ≤ LR < 0.6, then the optimal injection pressure is the current injection pressure plus 0.5 bar to 1.0 bar. If 0.6 ≤ LR < 0.8, then the optimal injection pressure is the current injection pressure plus 1.0 bar to 2.0 bar. If LR≥0.8, the optimal grease injection pressure is the current grease injection pressure plus 2.0 to 3.0 bar.

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