Automatic air pressure maintaining control method for air cushion bin in shield tunneling machine

Abstract

The invention discloses an automatic air pressure maintaining control method for an air cushion bin in a shield tunneling machine, which is applied to an automatic air pressure maintaining control system consisting 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 consists of a pressure sensor and a temperature sensor, and the execution module is connected with the detection module. The execution module is composed of a gas storage tank, a gas inlet valve and a gas outlet valve and is used for executing pressurization gas inlet and decompression gas outlet of the air cushion bin. The problem that pressure is adjusted by experience when a person enters an air cushion bin is solved, and parameters of the controller are automatically switched along with working conditions, so that dynamic adjustment is achieved, it is guaranteed that the whole system is in an efficient and stable operation state, and the monopoly of automatic adjustment of a foreign pressure maintaining system is broken through.

Description

Technical Field

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

[0002] The book "Shield and Key Technologies for Excavation" states: "A shield is a tunnel construction equipment used for tunnel excavation. It has a metal shell, and the whole machine and auxiliary equipment are installed inside the shell. Under the cover of the shield, soil excavation, soil slag transportation, whole machine propulsion and pipe segment installation are carried out, so that the tunnel is formed in one go." Modern shield machines integrate mechanical, electrical, hydraulic, sensor and information technology, and have been widely used in tunnel projects in the fields of subways, railways, highways, municipal administration, hydropower, etc. Since shield machines are used for underground excavation, the biggest risk in construction is unstable and sudden changes in face pressure. Once an accident occurs, it may cause huge economic losses and casualties.

[0003] The slurry system of the slurry shield consists of a double circuit of slurry and air. The excavation chamber is divided into a slurry chamber and an air pressure chamber by an immersed wall (Song Yunpu. Research on the control system of the main mechanism of the super-large diameter (15m) slurry shield [D]. Tongji University, 2008). The pressure of the supporting liquid is controlled by the air buffer layer of the air pressure chamber, thereby indirectly controlling the pressure of the excavation face. Compared with the direct control type, the indirect control slurry shield system is more complex, but due to the buffering effect of the air pressure chamber, it can reduce the influence of slurry flow control error, cutterhead speed change, propulsion speed change and formation change. At the same time, since the slurry flow control response is relatively slow and the pressure control of the air pressure chamber is relatively simpler than the slurry flow control, the control response is faster and the accuracy is higher, which is more suitable for tunnel construction with large diameter and complex formations.

[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 invention aims to solve the deficiencies of the above-mentioned prior art and proposes an automatic air pressure maintaining control method for an air cushion chamber in a shield machine, so as to enable the air cushion chamber pressure to quickly and automatically follow the target pressure without frequently adjusting the opening of the air inlet valve / exhaust valve, thereby making the overall pressure maintaining system more stable, thereby improving the operability and reliability of actual operations.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme:

[0007] The present invention is a method for automatically maintaining air pressure in an air cushion chamber in a shield machine. The method is characterized in that the method is applied to an automatic air pressure 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 air exhaust valve; the air inlet valve is arranged on a pipeline between the air storage tank and the air cushion chamber, and the air exhaust valve is arranged on an air outlet pipeline of the air cushion chamber. The automatic air pressure control method is performed according to the following steps:

[0008] Step 1: Determine the target pressure value P of the air cushion tank according to the mud water pressure at the center cut of the cutter head in the shield machine and the mud water level in the air cushion tank. e =P axe -ρ×g(HR), where P axe is the mud water pressure at the center cut of the shield machine cutterhead, ρ is the density of the mud in the air cushion chamber, g is the gravity acceleration, H is the liquid level of the air cushion chamber, and R is the cutterhead radius of the shield machine;

[0009] 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;

[0010] Step 3: Use the pressure sensor to determine the initial pressure value P0 of the air cushion chamber; and correct V according to P0 to obtain the equivalent volume V';

[0011] Step 4: Determine |P e - Is the pressure difference between P0| greater than k1×P e The product of, if so, when P e >P0, open the air inlet valve and select the fast charging mode to inflate the air cushion chamber. e ≤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;

[0012] 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;

[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, when P e >P1, open the air inlet valve and select trickle mode to inflate the air cushion chamber. e ≤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 maintain the pressure of the air cushion chamber. Otherwise, when P e >P2, open the air inlet valve to maintain trickle mode to inflate the air cushion chamber. e When ≤P2, open the exhaust valve to maintain the trickle mode to exhaust the air cushion chamber, where k3 is the air pressure tolerance coefficient.

[0016] An electronic device of the present invention includes a memory and a processor, wherein 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, wherein a computer program is stored on the computer-readable storage medium, and 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 the working mode 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, so that the control system is simplified, the air pressure control responds quickly, and the pressure maintaining system is more reliable and stable, which improves the operability and safety of actual operations and gets rid of the dependence on foreign pressure maintaining system control methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It 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 automatic air pressure-maintaining system of the shield machine of the present invention (illustrated by the inflation process);

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

[0023] Figure markings: 1-initial air pressure value; 2-target air pressure value; 3-pressure difference and target value comparison link; 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, an automatic air pressure-maintaining control method for 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 a pipeline between the air storage tank and the air cushion chamber, and the exhaust valve is arranged on an 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 material in the initial gas in the air cushion chamber 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: the fast charging and trickle charging module 4 or the slow charging and trickle charging module 7, wherein the initial air pressure difference and the 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 passing through the intake valve, during the intake process, only the intake valve opening needs to be adjusted once when switching from fast charging to trickle charging, 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 passing through the intake valve, during the intake process, only the intake valve opening needs to be adjusted once when switching from slow charging to trickle charging, 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 tank according to the mud water pressure at the center cut of the cutter head in the shield machine, the mud water level of the air cushion tank, and the characteristics of the internal pressure of the liquid. e =P axe -ρ×g(HR), where P axe is the mud water pressure at the center cut of the shield machine cutter head, ρ is the density of the mud in the air cushion chamber, g is the gravitational acceleration, H is the liquid level of the air cushion chamber, and R is the cutter head 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, 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: Use the pressure sensor to determine the initial pressure value P0 of the air cushion chamber; and correct V according to P0 to obtain the equivalent volume V';

[0031] Step 4: Determine |P e - Is the pressure difference between P0| greater than k1×P e The product of, if so, when P e >P0, open the air inlet valve and select the fast charging mode to inflate the air cushion chamber. e ≤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;

[0032] 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;

[0033] 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, when P e >P1, open the air inlet valve and select trickle mode to inflate the air cushion chamber. e ≤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.

[0034] 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;

[0035] 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 maintain the pressure of the air cushion chamber. Otherwise, when P e >P2, open the air inlet valve to maintain trickle mode to inflate the air cushion chamber. e When ≤P2, open the exhaust valve to maintain the trickle mode to exhaust the air cushion chamber, where k3 is the air pressure tolerance coefficient.

[0036] In this embodiment, an electronic device includes a memory and a processor, wherein the memory is used to store a program that supports the 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 on the computer-readable storage medium, and the computer program executes the steps of the above method when executed by a processor.

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, 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. 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 tank according to the mud water pressure at the center cut of the cutter head in the shield machine and the mud water level in the air cushion tank. e =P axe -ρ×g(HR), where P axe is the mud water pressure at the center cut of the shield machine cutterhead, ρ is the density of the mud in the air cushion chamber, g is the gravity acceleration, 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 according to P0 to obtain the equivalent volume V'; Step 4: Determine |P e - Is the pressure difference between P0| greater than k1×P e The product of, if so, when P e >P0, open the air inlet valve and select the fast charging mode to inflate the air cushion chamber. e ≤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, when P e >P1, open the air inlet valve and select trickle mode to inflate the air cushion chamber. e ≤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 maintain the pressure of the air cushion chamber. Otherwise, when P e >P2, open the air inlet valve to maintain trickle mode to inflate the air cushion chamber. e When ≤P2, open the exhaust valve to maintain the trickle 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 automatic air 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: The computer program executes the steps of the automatic air pressure maintaining control method according to claim 1 when executed by the processor.

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