An air automatic pressure maintaining control method for an air cushion bin in a shield machine

Abstract

The application discloses an air automatic pressure maintaining control method for an air cushion bin in a shield machine, and relates to an air automatic pressure maintaining control system composed of a control module, a detection module and an execution module. The control module controls the pressure of the air cushion bin in real time. The detection module is composed of a pressure sensor and a temperature sensor, and is responsible for real-time detection of the gas pressure value and temperature of the air cushion bin. The execution module is composed of a gas storage tank, an air inlet valve and an air outlet valve, and is responsible for air pressure increase and decrease of the air cushion bin. The application solves the problem of manual pressure adjustment in the air cushion bin according to experience, and enables the parameters of the controller to automatically switch with working conditions, so that dynamic adjustment is realized, the whole system is kept in an efficient and stable operation state, and the monopoly of foreign automatic pressure maintaining systems is broken.

Description

Technical Field

[0001] The invention belongs to the field of professional engineering machinery control, and in particular relates to an automatic air pressure maintaining control method for an air cushion chamber in a shield machine. Background Art

[0002] The book "Shield Machines and Key Technologies for Tunneling" states: "A shield machine is a tunnel construction device used for underground tunneling. It has a metal shell that houses the entire machine and auxiliary equipment. Under the protection of the shield, operations such as soil excavation, soil and debris removal, machine propulsion, and segment installation are performed, completing the tunnel construction in one go." Modern shield machines integrate mechanical, electrical, hydraulic, sensor, and information technologies and are widely used in tunneling projects in subways, railways, highways, municipal engineering, and hydropower. Because shield machines are underground tunneling machines, the greatest risk is unstable and sudden changes in face pressure. Accidents can result in significant economic losses and casualties.

[0003] The slurry shield's slurry system consists of a dual circuit of slurry and air. An immersed wall separates the excavation chamber into a slurry chamber and an air chamber (Song Yunpu. Research on the Control System of the Main Mechanism of an Ultra-Large Diameter (15-meter) Slurry Shield [D]. Tongji University, 2008). The pressure of the supporting fluid is controlled by the air buffer layer in the air chamber, thereby indirectly controlling the pressure at the excavation face. While the indirect control slurry shield system is more complex than the direct control system, the cushioning effect of the air chamber can reduce the effects of slurry flow control errors, cutterhead speed variations, propulsion speed variations, and stratum variations. Furthermore, because slurry flow control has a relatively slow response and air chamber pressure control is relatively simpler than slurry flow control, the control response is faster and the accuracy is higher, making it more suitable for tunnel construction in large diameter and complex strata.

[0004] Maintaining the stability of the face by automatically adjusting the pressure-maintaining control system with compressed air is one of the commonly used methods for shield equipment. The existing air cushion chamber pressure adjustment method, such as the air pressure adjustment method reported in the literature "Research on Air Cushion Chamber Pressure Maintaining Technology of Large Diameter Slurry Shield Machine" (Liu Aoyang, Zhong Qingfeng, Chen Liangwu, Li Haiyang, Wang Yu. "Construction Machinery", 2021, (02), pp.35-37.), uses the SAMSON system to ensure the stability of the air cushion chamber pressure. The SAMSON system is imported from abroad and has disadvantages such as complex structure, high price, and long delivery time. In addition, the pressure adjustment is mostly manually adjusted by the operator entering the pressure chamber, which poses a safety hazard. Therefore, studying the control method of the shield machine (air automatic) pressure maintaining system has important economic and social significance. Summary of the Invention

[0005] The present application is to solve the above-mentioned prior art existing deficiencies, put forward a kind of air automatic pressure maintaining control method for air cushion bin in shield machine, to realize that air cushion bin pressure quickly automatic follow target pressure, and no need frequent adjustment inlet valve / exhaust valve opening degree, it can make the whole pressure maintaining system more stable, to improve the actual operation operability and reliability.

[0006] The present application is to achieve the above-mentioned application purposes, and the following technical solutions are adopted:

[0007] The air automatic pressure maintaining control method for air cushion bin in shield machine has the characteristics that it is applied to an air automatic pressure maintaining control system composed of a control module, a detection module and an execution module, wherein the detection module includes a pressure sensor and a temperature sensor, and the execution module includes a gas storage tank, an inlet valve and an exhaust valve; the inlet valve is arranged on the pipeline between the gas storage tank and the air cushion bin, and the exhaust valve is arranged on the air outlet pipeline of the air cushion bin; and the air automatic pressure maintaining control method is performed according to the following steps:

[0008] Step 1, determining the target pressure value P of the air cushion bin according to the slurry pressure of the cutter head center cutout in the shield machine and the slurry liquid level of the air cushion bin e =P axe -ρ×g(H-R), wherein P axe is the slurry pressure of the cutter head center cutout in the shield machine, ρ is the density of the slurry in the air cushion bin, g is the acceleration of gravity, H is the liquid level of the air cushion bin, and R is the radius of the cutter head of the shield machine;

[0009] Step 2, constructing the gas state equation , wherein p is the pressure of the gas in the air cushion bin, V is the volume of the cavity of the air cushion bin, T is the temperature of the gas in the air cushion bin collected by the temperature sensor, M is the mass of the gas in the air cushion bin, μ is the molar mass of the gas in the air cushion bin, and R is the molar gas constant;

[0010] Step 3, determining the initial pressure value P0 of the air cushion bin by using the pressure sensor, and correcting V according to P0 to obtain the equivalent volume V';

[0011] Step 4, judging whether the pressure difference between |P e - P0| is greater than the product of k1×P e , if yes, then opening the inlet valve and selecting the fast charging mode to charge the air cushion bin when P e >P0, and opening the exhaust valve and selecting the fast exhaust mode to exhaust the air cushion bin when P e ≤P0, otherwise, executing step 5, wherein k1 is a set determination coefficient;

[0012] Step 5, opening the inlet valve and selecting the slow charging mode to charge the air cushion bin when Pe When ≤P0, open the exhaust valve and select the slow exhaust mode to exhaust the air cushion chamber;

[0013] Step 6: Use the pressure sensor to monitor the current pressure P1 of the air cushion chamber and determine |P e - Is the pressure difference between P1| less than k2×P e The product of, if so, then when P e >P1, open the air inlet valve and select the trickle mode to inflate the air cushion chamber. e When ≤P1, open the exhaust valve and select the trickle mode to exhaust the air cushion chamber. Otherwise, execute step 7, where k2 is the determination coefficient for switching to trickle mode.

[0014] Step 7. Open the air inlet valve and keep the fast charging mode to inflate the air cushion chamber. e When ≤P1, open the exhaust valve and keep the quick exhaust mode to exhaust the air cushion chamber;

[0015] Step 8: Use the pressure sensor to monitor the current pressure value P2 of the air cushion chamber and determine |P e - Is the pressure difference between P2| less than k3×P e If yes, close the air inlet valve or the exhaust valve to complete the pressure maintenance of the air cushion chamber. Otherwise, when P e >P2, open the air inlet valve to maintain the trickle mode to inflate the air cushion chamber. e When ≤P2, open the exhaust valve and maintain the trickle flow mode to exhaust the air cushion chamber, where k3 is the air pressure tolerance coefficient.

[0016] The electronic device of the present invention includes a memory and a processor, and is characterized in that the memory is used to store a program that supports the processor to execute the automatic air pressure maintaining control method, and the processor is configured to execute the program stored in the memory.

[0017] The present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program executes the steps of the automatic air pressure maintaining control method when the computer program is executed by a processor.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention can automatically switch working modes according to different working conditions, and the controller parameters are automatically adjusted dynamically without manual operation. The entire intake / exhaust process adopts a segmented intake / exhaust method, and there is no need to frequently adjust the intake / exhaust valve opening, which simplifies the control system, makes the air pressure control respond quickly, and makes the pressure maintaining system more reliable and stable, thereby improving the operability and safety of actual operations and getting rid of dependence on foreign pressure maintaining system control methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a block diagram of the air cushion chamber pressure maintaining system for the shield machine air automatic pressure maintaining system of the present invention;

[0021] Figure 2 This is the internal principle diagram of the controller design for the shield machine air automatic pressure maintaining system of the present invention (illustrated by the inflation process);

[0022] Figure 3 This is a flow chart of the shield machine automatic air pressure maintaining system control method of the present invention for adjusting the air pressure value to balance the tunnel face pressure;

[0023] Figure numerals: 1-initial air pressure value; 2-target air pressure value; 3-comparison link between air pressure difference and target value; 4-fast charging and trickle charging air intake control module; 5-mass flow air intake; 6-tolerance control module; 7-slow charging and trickle charging air intake control module; 8-tolerance control module; 9-mass flow air intake; 10-real-time air pressure monitoring display. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to the accompanying drawings.

[0025] In this embodiment, a method for automatically maintaining air pressure in an air cushion chamber in a shield machine is applied to an automatic air pressure maintaining control system composed of a control module, a detection module, and an execution module, wherein the detection module includes: a pressure sensor and a temperature sensor, and the execution module includes: an air storage tank, an air inlet valve, and an exhaust valve; the air inlet valve is arranged on the pipeline between the air storage tank and the air cushion chamber, and the exhaust valve is arranged on the air outlet pipeline of the air cushion chamber, such as Figure 1 As shown;

[0026] In this case, a control method for the automatic air pressure maintaining system of a shield machine focuses on the controller design. The controller has a built-in mathematical model. The initial air pressure value 1 calculates the amount of the initial gas in the air cushion based on the built mathematical model as the initial condition for air intake; the difference between the initial air pressure value 1 and the target air pressure value 2 is automatically selected through the comparison link 3 to select the air intake mode: fast charging and trickle charging module 4 or slow charging and trickle charging module 7, wherein the initial air pressure difference and target value comparison link 3 sets the judgment condition according to the actual working condition; the fast charging and trickle charging air intake control module 4 is connected to the tolerance control module 6, and the set tolerance (the difference between the measured air pressure value and the target air pressure value) is required as the switching condition from fast charging to trickle charging during inflation; the slow charging and trickle charging air intake control module 7 is connected to the tolerance control module 8, and the set tolerance (the difference between the measured air pressure value and the target air pressure value) is required as the switching condition from fast charging to trickle charging during inflation. The difference between the value and the target air pressure value) is required as the switching condition from slow charging to trickle charging; the mass flow rate of air intake 5 is determined by the fast charging and trickle charging air intake control module 4 to determine the mass flow rate at each moment, and the mass flow rate is set to a constant value in the fast charging stage and the trickle charging stage. In this way, according to the aerodynamic characteristics of air when passing through the intake valve, it is only necessary to adjust the intake valve opening once when switching from fast charging to trickle charging during the intake process, and there is no need to adjust the opening frequently; the mass flow rate of air intake 9 is determined by the slow charging and trickle charging air intake control module 8 to determine the mass flow rate at each moment, and the mass flow rate is set to a constant value in the slow charging stage and the trickle charging stage. In this way, according to the aerodynamic characteristics of air when passing through the intake valve, it is only necessary to adjust the intake valve opening once when switching from slow charging to trickle charging during the intake process, and there is no need to adjust the opening frequently; the real-time air pressure monitoring display 10 displays the air pressure value in real time, such as Figure 2 As shown in the figure.

[0027] In this embodiment, Figure 3 As shown, the automatic air pressure maintaining control method is performed in the following steps:

[0028] Step 1: Determine the target pressure value P of the air cushion chamber based on the mud and water pressure at the center cut of the shield machine cutterhead, the mud and water level of the air cushion chamber, and the characteristics of the internal pressure of the liquid. e =P axe -ρ×g(HR), where P axe is the mud and water pressure at the center cutterhead of the shield machine, ρ is the density of the mud in the air cushion chamber, g is the acceleration of gravity, H is the liquid level of the air cushion chamber, and R is the cutterhead radius of the shield machine.

[0029] Step 2: Construct the gas state equation , it can be seen that the gas pressure p is proportional to the gas mass M, so the pressure can be adjusted by adjusting the gas mass in the air cushion chamber; where p is the pressure of the gas in the air cushion chamber, V is the volume of the air cushion chamber cavity, T is the temperature of the air cushion chamber gas collected by the temperature sensor, M is the mass of the gas in the air cushion chamber, μ is the molar mass of the gas in the air cushion chamber, and R is the molar gas constant;

[0030] Step 3, determine the initial pressure value P0 of the air cushion chamber by using the pressure sensor, and correct V according to P0 to obtain the equivalent volume V';

[0031] Step 4, judge whether the pressure difference between |P e - P0| is greater than the product of k1×P e , if yes, when P e >P0, open the air inlet valve and select the fast charging mode to charge the air cushion chamber, when P e ≤P0, open the air outlet valve and select the fast exhaust mode to exhaust the air cushion chamber, otherwise, execute step 5, wherein k1 is a set determination coefficient;

[0032] Step 5, open the air inlet valve and select the slow charging mode to charge the air cushion chamber, when P e ≤P0, open the air outlet valve and select the slow exhaust mode to exhaust the air cushion chamber;

[0033] Step 6, monitor the current pressure P1 of the air cushion chamber by using the pressure sensor, and judge whether the pressure difference between |P e - P1| is less than the product of k2×P e , if yes, when P e >P1, open the air inlet valve and select the trickle mode to charge the air cushion chamber, when P e ≤P1, open the air outlet valve and select the trickle mode to exhaust the air cushion chamber, otherwise, execute step 7, wherein k2 is a determination coefficient for switching the trickle.

[0034] Step 7, open the air inlet valve to keep the fast charging mode to charge the air cushion chamber, when P e ≤P1, open the air outlet valve and keep the fast exhaust mode to exhaust the air cushion chamber;

[0035] Step 8, monitor the current pressure value P2 of the air cushion chamber by using the pressure sensor, judge whether the pressure difference between |P e - P2| is less than the product of k3×P e , if yes, close the air inlet valve or the air outlet valve, thereby completing the pressure maintaining of the air cushion chamber, otherwise, when P e >P2, open the air inlet valve to keep the trickle mode to charge the air cushion chamber, when P e ≤P2, open the air outlet valve to keep the trickle mode to exhaust the air cushion chamber, wherein k3 is a pressure tolerance coefficient.

[0036] In the embodiment, an electronic device includes a memory for storing a program supporting a processor to execute the above method, and the processor is configured to execute the program stored in the memory.

[0037] In this embodiment, a computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are executed.

Claims

1. A method for automatically maintaining air pressure in an air cushion chamber of a shield machine, characterized in that: It is applied to an automatic air pressure-maintaining control system composed of a control module, a detection module, and an execution module. The detection module includes a pressure sensor and a temperature sensor, and the execution module includes an air storage tank, an air inlet valve, and an air exhaust valve. The air inlet valve is arranged on the pipeline between the air storage tank and the air cushion chamber, and the air exhaust valve is arranged on the air outlet pipeline of the air cushion chamber. The automatic air pressure-maintaining control method is performed according to the following steps: Step 1: Determine the target pressure value P of the air cushion chamber according to the mud and water pressure at the center cut of the shield machine cutter head and the mud and water level of the air cushion chamber. e =P axe -ρ×g(HR), where P axe is the mud and water pressure at the center cutterhead of the shield machine, ρ is the density of the mud in the air cushion chamber, g is the acceleration of gravity, H is the liquid level of the air cushion chamber, and R is the cutterhead radius of the shield machine; Step 2: Construct the gas state equation , where p is the pressure of the gas in the air cushion chamber, V is the volume of the air cushion chamber, T is the temperature of the air cushion chamber gas collected by the temperature sensor, M is the mass of the gas in the air cushion chamber, μ is the molar mass of the gas in the air cushion chamber, and R is the molar gas constant; Step 3: Use the pressure sensor to determine the initial pressure value P0 of the air cushion chamber; and correct V based on P0 to obtain the equivalent volume V'; Step 4, judge |P e - Is the pressure difference between P0| greater than k1×P e The product of, if so, then when P e >P0, open the air inlet valve and select the fast charging mode to inflate the air cushion chamber. e When ≤P0, open the exhaust valve and select the quick exhaust mode to exhaust the air cushion chamber. Otherwise, execute step 5, where k1 is the set determination coefficient; Step 5. Open the air inlet valve and select the slow filling mode to inflate the air cushion chamber. e When ≤P0, open the exhaust valve and select the slow exhaust mode to exhaust the air cushion chamber; Step 6: Use the pressure sensor to monitor the current pressure P1 of the air cushion chamber and determine |P e - Is the pressure difference between P1| less than k2×P e The product of, if so, then when P e >P1, open the air inlet valve and select the trickle mode to inflate the air cushion chamber. e When ≤P1, open the exhaust valve and select the trickle mode to exhaust the air cushion chamber. Otherwise, execute step 7, where k2 is the determination coefficient for switching to trickle mode. Step 7. Open the air inlet valve and keep the fast charging mode to inflate the air cushion chamber. e When ≤P1, open the exhaust valve and keep the quick exhaust mode to exhaust the air cushion chamber; Step 8: Use the pressure sensor to monitor the current pressure value P2 of the air cushion chamber and determine |P e - Is the pressure difference between P2| less than k3×P e If yes, close the air inlet valve or the exhaust valve to complete the pressure maintenance of the air cushion chamber. Otherwise, when P e >P2, open the air inlet valve to maintain the trickle mode to inflate the air cushion chamber. e When ≤P2, open the exhaust valve and maintain the trickle flow mode to exhaust the air cushion chamber, where k3 is the air pressure tolerance coefficient.

2. An electronic device comprising a memory and a processor, characterized in that: The memory is used to store a program that supports the processor to execute the air automatic pressure maintaining control method according to claim 1, and the processor is configured to execute the program stored in the memory.

3. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the automatic air pressure maintaining control method according to claim 1 are executed.

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