A method for opening and changing cutters of an earth pressure balance shield machine for pressure-maintaining and gas-transportation
Through the method of keeping pressure and moving gas in the soil warehouse, the problem of difficult gas concentration when the soil pressure balance shield machine is excavated into high gas formations is solved, ensuring tool replacement under safe conditions, avoiding power outage of the machine, and improving operating efficiency and Security.
Patent Information
- Application Number
- CN202410533022.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-30
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2044-04-30
AI Technical Summary
When the soil pressure balance shield machine digs into high-gas formations, the existing technology is difficult to effectively reduce the gas concentration in the soil warehouse, resulting in the inability to open the warehouse safely and change the tool, triggering the wind power locking mechanism, causing the machine to be powered off, and the replacement of worn tools cannot be completed. .
The method of gas transporting pressure in the soil silo is used to close the pressure relief valve, and air is injected into the soil silo using air compressors and foam pipelines, and the gas gas is gradually transported and squeezed into the formation cracks to control the gas concentration in the soil silo. Within the limit value, ensure that the earthen warehouse door is opened for tool replacement within the safe period.
It realizes the reduction of the vas concentration in the soil warehouse under safe conditions, avoids triggering the wind power locking mechanism, ensures that the soil pressure balance shield mechanism is constantly powered, and improves the operation efficiency and safety of opening and changing positions.
Smart Images
Figure CN118361250B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of earth pressure balance shield machine tunneling and excavation, and in particular relates to a method for opening and changing cutters for pressure-maintaining and gas-transporting earth pressure balance shield machine. Background Art
[0002] In the process of excavating high-gas strata using an earth pressure balance shield machine, when the gas concentration inside the soil bin of the earth pressure balance shield machine is high, it is impossible to enter the soil bin to replace the worn tools. The worn tools can only be replaced when the gas concentration inside the soil bin is less than the gas concentration limit. Currently, there are two proposed implementation methods. The first is to use an air compressor and a foam pipeline to continuously inject air into the soil bin with the soil bin door closed and the balance valve opened, so as to achieve the purpose of replacing the gas inside the soil bin, until the gas concentration inside the soil bin is reduced to above the gas concentration limit. However, after field tests, it was found that the gas concentration inside the soil bin changed very little and had basically no effect, resulting in the inability to open the bin and change cutters; the second was to directly open the soil bin door to discharge the gas inside the soil bin naturally. A large amount of high-concentration gas inside the soil bin escaped from the soil bin door. When the methane sensor of the earth pressure balance shield machine detected that the methane concentration reached 1%, it would cause the earth pressure balance shield machine to trigger the wind power locking mechanism, causing the entire earth pressure balance shield machine to be powered off, and the cutter changing operation could not be achieved at all; therefore, a method for opening the bin and changing cutters for an earth pressure balance shield machine that is easy to operate and maintains pressure to transport gas should be provided. Summary of the invention
[0003] The technical problem to be solved by the present invention is to provide a method for opening and changing cutters of an earth pressure balance shield machine while maintaining pressure and transporting gas. The method adopts the method of maintaining pressure and transporting gas in the earth bin, which can transport and squeeze the gas in the earth bin into the stratum cracks and control the gas concentration in the earth bin within the limit value of the gas concentration. At this time, the earth bin is in a safe operating period. Opening the earth bin door within the safe operating period will not trigger the wind power locking mechanism, will not cause the earth pressure balance shield machine to be powered off, and can complete the replacement of worn cutters.
[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for opening and changing cutters of an earth pressure balance shield machine for pressure-maintaining and gas-transportation, characterized in that the method comprises the following steps:
[0005] Step 1: Close all the pressure relief valves installed on the soil bin of the earth pressure balance shield machine to keep the soil bin in a closed state;
[0006] Step 2: continuously inject air into the soil bin to pressurize and maintain the soil bin:
[0007] Air is continuously injected into the soil bin by using an air compressor and a foam pipeline, and the air supply volume of the air compressor is set to the initial air supply volume. During the continuous pressurization process, the internal pressure of the soil bin is detected in real time. When the actual pressure value inside the soil bin detected in real time is greater than the maximum value of the gas outflow pressure of a single hole in the tunnel, the air supply volume of the air compressor is adjusted to the air supply volume of the foam pipeline, and the pressure is maintained so that the gas inside the soil bin is fully transported and squeezed into the stratum fissures;
[0008] Step 3: Open all the pressure relief valves installed on the soil bin of the earth pressure balance shield machine to release the pressure;
[0009] During the continuous pressure relief process, the internal pressure of the soil bin is detected in real time. When the actual pressure value inside the soil bin detected in real time is equal to 0 MPa, the soil bin door is opened, and the gas concentration inside the soil bin is detected multiple times. When the gas concentration value inside the soil bin detected is less than the gas concentration limit value, the gas concentration limit value is 0.5%, and step 4 is executed; when the gas concentration value inside the soil bin detected is not less than the gas concentration limit value, the soil bin door is closed, and step 1 is executed;
[0010] Step 4: Construction personnel enter the soil bin to replace worn cutting tools:
[0011] In the process of replacing the worn tool, the air compressor and the foam pipeline are used to continuously inject air into the soil bin, and the air supply of the air compressor is made equal to the air supply of the foam pipeline; and the gas concentration inside the soil bin is detected multiple times. When the gas concentration value inside the soil bin detected is not less than the gas concentration limit value, the construction personnel withdraw from the soil bin, close the soil bin door, and execute step 1;
[0012] Step 5: Repeat steps 1 to 4 several times until all worn tools are replaced.
[0013] The above-mentioned method for opening and changing cutters for pressure-maintaining and gas-transporting earth pressure balance shield machine is characterized in that: in step 2, the initial air supply volume is not less than 2m3 / min.
[0014] The above-mentioned method for opening and changing cutters for maintaining pressure and transporting gas through an earth pressure balance shield machine is characterized in that in step 2 and step 4, the value range of the air supply volume of the foam pipeline is 0.15m3 / min to 1.5m3 / min.
[0015] The above-mentioned method for opening and changing cutters for maintaining pressure and transporting gas by an earth pressure balance shield machine is characterized in that: in step 2, the value range of the gas outflow pressure of the single hole in the tunnel is 0.08MPa~0.14MPa, and the value range of the measured pressure value inside the earth bin is 0.15MPa~0.3MPa.
[0016] The above-mentioned method for opening and changing cutters for maintaining pressure and transporting gas by an earth pressure balance shield machine is characterized in that: in step 2, the duration of maintaining pressure ranges from 5 to 8 hours.
[0017] Compared with the prior art, the present invention has the following advantages:
[0018] 1. The present invention adopts a method of maintaining pressure and transporting gas in the soil bin. The specific operation process of maintaining pressure and transporting gas in the soil bin is: first close all pressure relief valves installed on the soil bin of the earth pressure balance shield machine to keep the soil bin in a closed state; use an air compressor to continuously inject air into the soil bin with an initial air supply volume to pressurize the soil bin; when the actual pressure value inside the soil bin detected in real time is greater than the maximum value of the gas outflow pressure of a single hole in the tunnel, adjust the air supply volume of the air compressor to the foam pipeline air supply volume to maintain pressure. During the pressure maintenance process, the gas inside the soil bin can be fully transported and squeezed into the stratum fissures, and the gas concentration in the soil bin can be controlled within the gas concentration limit value. At this time, the soil bin is in a safe operating period. Opening the soil bin door within the safe operating period will not trigger the wind power locking mechanism, will not cause the earth pressure balance shield machine to be powered off, and can complete the replacement of worn tools.
[0019] 2. During the continuous pressure relief process, the present invention performs real-time detection of the internal pressure of the soil bin. When the actual pressure value inside the soil bin obtained by real-time detection is equal to 0 MPa, the soil bin door is opened, and the gas concentration inside the soil bin is detected multiple times. When the detected gas concentration value inside the soil bin is less than the gas concentration limit value, the gas concentration limit value is 0.5%, and the construction personnel can enter the soil bin to replace the worn cutting tools; if the detected gas concentration value inside the soil bin is not less than the gas concentration limit value, it is necessary to close the soil bin door, and continue to repeat the soil bin pressure maintenance and gas migration, so as to fully migrate and squeeze the gas inside the soil bin into the formation fissures, until the detected gas concentration value inside the soil bin is less than the gas concentration limit value.
[0020] 3. The present invention has a reasonable design, improves the operating efficiency and safety of opening and changing cutters of an earth pressure balance shield machine, and is easy to promote and apply.
[0021] In summary, the present invention is reasonably designed. By adopting the method of maintaining pressure in the soil bin to transport gas, the gas in the soil bin can be transported and squeezed into the stratum cracks, and the gas concentration in the soil bin can be controlled within the gas concentration limit value. At this time, the soil bin is in a safe operating period. Opening the soil bin door within the safe operating period will not trigger the wind power locking mechanism, will not cause the earth pressure balance shield machine to be powered off, and the worn cutting tools can be replaced.
[0022] The present invention is further described in detail below through the accompanying drawings and examples. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION
[0024] like Figure 1 A method for opening and changing cutters for pressure-maintaining and gas-transporting earth pressure balance shield machine is shown, and the method comprises the following steps:
[0025] Step 1: Close all the pressure relief valves installed on the soil bin of the earth pressure balance shield machine to keep the soil bin in a closed state;
[0026] Step 2: continuously inject air into the soil bin to pressurize and maintain the soil bin:
[0027] Air is continuously injected into the soil bin by using an air compressor and a foam pipeline, and the air supply volume of the air compressor is set to the initial air supply volume. During the continuous pressurization process, the internal pressure of the soil bin is detected in real time. When the actual pressure value inside the soil bin detected in real time is greater than the maximum value of the gas outflow pressure of a single hole in the tunnel, the air supply volume of the air compressor is adjusted to the air supply volume of the foam pipeline, and the pressure is maintained so that the gas inside the soil bin is fully transported and squeezed into the stratum fissures;
[0028] Step 3: Open all the pressure relief valves installed on the soil bin of the earth pressure balance shield machine to release the pressure;
[0029] During the continuous pressure relief process, the internal pressure of the soil bin is detected in real time. When the actual pressure value inside the soil bin detected in real time is equal to 0 MPa, the soil bin door is opened, and the gas concentration inside the soil bin is detected multiple times. When the gas concentration value inside the soil bin detected is less than the gas concentration limit value, the gas concentration limit value is 0.5%, and step 4 is executed; when the gas concentration value inside the soil bin detected is not less than the gas concentration limit value, the soil bin door is closed, and step 1 is executed;
[0030] Step 4: Construction personnel enter the soil bin to replace worn cutting tools:
[0031] In the process of replacing the worn tool, the air compressor and the foam pipeline are used to continuously inject air into the soil bin, and the air supply of the air compressor is made equal to the air supply of the foam pipeline; and the gas concentration inside the soil bin is detected multiple times. When the gas concentration value inside the soil bin detected is not less than the gas concentration limit value, the construction personnel withdraw from the soil bin, close the soil bin door, and execute step 1;
[0032] Step 5: Repeat steps 1 to 4 several times until all worn tools are replaced.
[0033] In this embodiment, in step 2, the initial air supply volume is not less than 2m3 / min.
[0034] In this embodiment, in step 2 and step 4, the air supply volume of the foam pipeline ranges from 0.15m3 / min to 1.5m3 / min.
[0035] In this embodiment, in step 2, the value range of the gas outburst pressure of the single hole in the tunnel is 0.08MPa to 0.14MPa, and the value range of the measured pressure value inside the soil bin is 0.15MPa to 0.3MPa.
[0036] In this embodiment, in step 2, the duration of pressure holding is in the range of 5 to 8 hours.
[0037] In this embodiment, since the gas concentration of the project increased sharply after investigation, gushing occurred. The gas concentration at the borehole mouth outside the gas discharge ranged from 68% to 100%, the gas outflow of a single tunnel hole ranged from 0.127m3 / min to 0.315m3 / min, and the gas outflow pressure of a single tunnel hole ranged from 0.08MPa to 0.14MPa. According to on-site calculations, the maximum gas outflow was much greater than 0.5m3 / min, and it was a high-gas and high-risk tunnel section. The project used an earth pressure balance shield machine for excavation, and the earth pressure balance shield machine was an explosion-proof type as a whole machine. A total of 14 methane sensors were installed at three locations: the front shield, the shield tail, and the auxiliary cabin door. The earth pressure balance shield machine was equipped with a wind power locking mechanism. When the shield machine's methane sensor sensed that the methane concentration reached 1%, the wind power locking mechanism would be automatically activated, and the earth pressure balance shield machine would be powered off.
[0038] During the excavation process of the earth pressure balance shield machine, when the worn tool needs to be replaced, if the soil bin door is opened directly, the gas in the soil bin will escape quickly. When the methane sensor senses that the methane concentration has reached 1%, the wind power locking mechanism is triggered, causing the entire earth pressure balance shield machine to be powered off, and the tool replacement operation cannot be achieved at all. Therefore, the present invention adopts a method of maintaining pressure in the soil bin to transport the gas. The specific operation process of maintaining pressure in the soil bin to transport the gas is as follows: first close all the pressure relief valves installed on the soil bin of the earth pressure balance shield machine to keep the soil bin in a closed state; use an air compressor to continuously inject air into the soil bin at an initial air supply volume Gas is used to pressurize the soil bin; when the actual pressure value inside the soil bin detected in real time is greater than the maximum value of the gas outburst pressure of a single hole in the tunnel, the air supply of the air compressor is adjusted to the air supply of the foam pipeline to implement pressure maintenance. During the pressure maintenance process, the gas inside the soil bin can be fully transported and squeezed into the stratum cracks, and the gas concentration in the soil bin can be controlled within the gas concentration limit. At this time, the soil bin is in a safe operating period. Opening the soil bin door within the safe operating period will not trigger the wind power locking mechanism, will not cause the earth pressure balance shield machine to be powered off, and the worn cutting tools can be replaced.
[0039] The actual operation process is:
[0040] At 8:10 on the first day, air was continuously injected into the soil bin, with an initial air volume of 2m 3 / min, after continuously injecting air for 2 hours and 30 minutes, the actual pressure value inside the soil bin detected at 10:40 on the first day was 1.7bar, and the initial air supply was reduced to the foam pipeline air supply to maintain pressure. The foam pipeline air supply was 0.5m3 / min, so that the gas inside the soil bin could be fully transported and squeezed into the stratum cracks. After maintaining pressure for 6 hours, all the pressure relief valves installed on the soil bin of the earth pressure balance shield machine were opened at 16:40 on the first day to start pressure relief. The balancing valve and the drain valve were opened during pressure relief. After pressure relief, the water in the soil bin overflowed from the drain valve.
[0041] During the continuous pressure relief process, the internal pressure of the soil bin was detected in real time. At 16:47 on the first day, the measured pressure value inside the soil bin was equal to 0MPa. The soil bin door was then opened, and the gas concentration inside the soil bin was detected every ten minutes. The detection results were recorded in Table 1, and the soil bin door was closed at 18:00. The soil bin door was opened for 73 minutes, and the gas concentration inside the soil bin was detected 9 times. The 9 detection results all showed that the gas concentration (methane concentration) inside the soil bin was less than 0.5%, meeting the conditions for tool change. However, this test did not implement the replacement of worn tools. It was only by verifying the feasibility of steps one to three in this operation that the gas concentration value inside the soil bin could be controlled within the gas concentration limit within 73 minutes.
[0042] Table 1
[0043] time Soil bin pressure (bar) Methane concentration (%) Foam pipeline air supply volume (m3 / min) Methane Testing Locations 16:40 1.7 / 0 / 16:40 1.6 / 0 / 16:41 1.5 / 0 / 16:42 1.4 / 0 / 16:43 1.3 / 0 / 16:43 1.2 / 0 / 16:44 1.1 / 0 / 16:44 1.0 / 0 / 16:45 0.9 / 0 / 16:45 0.8 / 0 / 16:46 0.7 / 0 / 16:46 0.6 / 0 / 16:46 0.5 / 0 / 16:46 0.4 / 0 / 16:47 0.3 / 0 / 16:47 0.2 / 0 / 16:47 0.1 / 0 / 16:47 0 0 0 Balancing valve outlet 16:57 0 0.06 0.5 In the earthen warehouse 17:07 0 0.12 0.5 In the earthen warehouse 17:17 0 0.05 0.5 In the earthen warehouse 17:27 0 0.05 0.5 In the earthen warehouse 17:37 0 0.05 0.5 In the earthen warehouse 17:47 0 0.05 0.5 In the earthen warehouse 17:57 0 0.05 0.5 In the earthen warehouse 18:00 0 0.05 0.5 In the earthen warehouse
[0044] The gas concentration inside the soil bin detected at 19:22 on the first day was greater than the gas concentration limit of 0.5%. The soil bin door was closed and air was continuously injected into the soil bin again. The initial air supply was 2 m / min. After 4 hours and 10 minutes of continuous air injection, the actual pressure inside the soil bin was 1.7 bar at 23:32 on the first day. After that, the initial air supply was reduced to the foam pipeline air supply, and the pressure was maintained. The value range of the foam pipeline air supply was 0.05 m / min to 0.1 m / min, so that the gas inside the soil bin was fully transported and squeezed into the formation cracks. After the pressure was maintained for 9 hours and 30 minutes, it may be As the parameters of the foam pipeline air supply volume were set too low, the actual pressure inside the soil bin was detected to be 2.2 bar at 10:06 on the second day. After that, the initial air supply volume was reduced to the foam pipeline air supply volume, and the pressure maintenance was re-implemented. This time, the value range of the foam pipeline air supply volume was set to 0.15m / min~0.30m / min, so that the gas inside the soil bin could be fully transported and squeezed into the stratum cracks. After the pressure maintenance time was 5 hours and 7 minutes, all the pressure relief valves installed on the soil bin of the earth pressure balance shield machine were opened at 15:15 on the second day to start pressure relief. During the pressure relief, the balancing valve, drain valve and screw machine were opened. After the pressure relief, the water in the soil bin was discharged through the screw machine.
[0045] During the continuous pressure relief process, the internal pressure of the soil bin was detected in real time. At 15:22 on the second day, the actual pressure value inside the soil bin was equal to 0 MPa. The soil bin door was then opened and closed at 16:20 on the second day. The gas concentration inside the soil bin was detected multiple times and the detection results are recorded in Table 2. The soil bin door was opened for 53 minutes and the gas concentration inside the soil bin was detected 8 times. The 8 detection results all showed that the gas concentration (methane concentration) inside the soil bin was lower than 0.5%. During this period, the construction personnel entered the soil bin to complete the replacement of the first worn tool.
[0046] Table 2
[0047] time Soil bin pressure (bar) Methane concentration (%) <![CDATA[Foam pipeline air supply volume (m 3 / min)]]> Methane Testing Locations 15:15 2.2 / 0 / 15:18 1.5 / 0 / 15:20 1.1 / 0 / 15:21 0.1 / 0 / 15:22 0 / 0 / 15:23 0 0 0.26 Balancing valve outlet 15:29 0 0 0.26 In the earthen warehouse 15:32 0 0.07 0 In the earthen warehouse 15:38 0 0 0.19 In the earthen warehouse 15:40 0 0.04 0.19 In the earthen warehouse 15:45 0 0.05 0.19 In the earthen warehouse 16:17 0 0.4 0 Balancing valve outlet 16:20 0 0.5 0 Balancing valve outlet
[0048] At 16:22 on the second day, the gas concentration value inside the soil bin detected was greater than the gas concentration limit of 0.5%. The construction workers evacuated the soil bin and closed the soil bin door. At 18:30 on the second day, air was continuously injected into the soil bin again, wherein the initial air supply volume was 2m / min. After the air was continuously injected for 6 hours, the measured pressure value inside the soil bin was 2.1bar at 24:30 on the second day. After that, the initial air supply volume was reduced to the foam pipeline air supply volume, and the pressure was maintained again. This time, the value range of the foam pipeline air supply volume was set to 0.15m / min~0.30m / min, so that the gas inside the soil bin could be fully transported and squeezed into the stratum fissures. After the pressure was maintained for 8 hours, all the pressure relief valves installed on the soil bin of the earth pressure balance shield machine were opened at 8:31 on the third day to start pressure relief. During the pressure relief, the balance valve, the drain valve and the screw machine were opened. After the pressure relief, the water in the soil bin was discharged through the screw machine.
[0049] During the continuous pressure relief process, the internal pressure of the soil bin was detected in real time. At 8:38 on the third day, the actual pressure value inside the soil bin was equal to 0 MPa, and the soil bin door was opened immediately. The soil bin door was opened at 8:43 on the third day and closed at 10:23 on the third day. The gas concentration inside the soil bin was detected multiple times, and the detection results are recorded in Table 3. The soil bin door was opened for 100 minutes, and the gas concentration inside the soil bin was detected 13 times. The 13 detection results all showed that the gas concentration (methane concentration) inside the soil bin was lower than 0.5%. During this period, the construction personnel entered the soil bin to complete the replacement of the second worn tool.
[0050] Table 3
[0051] time Soil bin pressure (bar) Methane concentration (%) <![CDATA[Foam pipeline air supply volume (m 3 / min)]]> Methane Testing Locations 8:31 2.1 / 0 / 8:33 1.7 / 0 / 8:34 1.2 / 0 / 8:35 0.7 / 0 / 8:38 0 0 0 Balancing valve outlet 8:43 0 0 1 In the earthen warehouse 8:50 0 0 1 In the earthen warehouse 9:07 0 0.04 1 In the earthen warehouse 9:24 0 0.05 0.2 In the earthen warehouse 9:25 0 0.05 0.4 In the earthen warehouse 9:41 0 0.08 0.4 In the earthen warehouse 9:54 0 0.10 0.4 In the earthen warehouse 10:08 0 0.13 1 In the earthen warehouse 10:11 0 0.13 0.9 In the earthen warehouse 10:17 0 0.08 0.9 In the earthen warehouse 10:20 0 0.16 0.9 In the earthen warehouse 10:23 0 0.17 1.5 In the earthen warehouse
[0052] After repeating steps one to four many times until all worn tools are replaced, and by repeatedly adopting the method of maintaining pressure in the soil bin to transport gas, the entire tool changing process is easy to operate and has high safety. It will not trigger the wind power locking mechanism and will not cause the entire earth pressure balance shield machine to lose power, and is easy to promote and apply.
[0053] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.
Claims
1. A method for opening and changing cutters of an earth pressure balance shield machine for pressure-maintaining and gas-transportation, characterized in that: The method comprises the following steps: Step 1: Close all the pressure relief valves installed on the soil bin of the earth pressure balance shield machine to keep the soil bin in a closed state; Step 2: continuously inject air into the soil bin to pressurize and maintain the soil bin: Air is continuously injected into the soil bin by using an air compressor and a foam pipeline, and the air supply volume of the air compressor is set to the initial air supply volume. During the continuous pressurization process, the internal pressure of the soil bin is detected in real time. When the actual pressure value inside the soil bin detected in real time is greater than the maximum value of the gas outflow pressure of a single hole in the tunnel, the air supply volume of the air compressor is adjusted to the air supply volume of the foam pipeline, and the pressure is maintained so that the gas inside the soil bin is fully transported and squeezed into the stratum fissures; Step 3: Open all the pressure relief valves installed on the soil bin of the earth pressure balance shield machine to release the pressure; During the continuous pressure relief process, the internal pressure of the soil bin is detected in real time. When the actual pressure value inside the soil bin detected in real time is equal to 0 MPa, the soil bin door is opened, and the gas concentration inside the soil bin is detected multiple times. When the gas concentration value inside the soil bin detected is less than the gas concentration limit value, the gas concentration limit value is 0.5%, and step 4 is executed; when the gas concentration value inside the soil bin detected is not less than the gas concentration limit value, the soil bin door is closed, and step 1 is executed; Step 4: Construction personnel enter the soil bin to replace worn cutting tools: In the process of replacing the worn tool, the air compressor and the foam pipeline are used to continuously inject air into the soil bin, and the air supply of the air compressor is made equal to the air supply of the foam pipeline; and the gas concentration inside the soil bin is detected multiple times. When the gas concentration value inside the soil bin detected is not less than the gas concentration limit value, the construction personnel withdraw from the soil bin, close the soil bin door, and execute step 1; Step 5: Repeat steps 1 to 4 several times until all worn tools are replaced.
2. A method for opening and changing cutters for pressure-maintaining and gas-transporting earth pressure balance shield machine according to claim 1, characterized in that: In step 2, the initial air supply volume is not less than 2m 3 / min.
3. A method for opening and changing cutters for pressure-maintaining and gas-transporting earth pressure balance shield machine according to claim 1, characterized in that: In step 2 and step 4, the value range of the air supply volume of the foam pipeline is 0.15m 3 / min~1.5m 3 / min.
4. A method for opening and changing cutters for pressure-maintaining and gas-transporting earth pressure balance shield machine according to claim 1, characterized in that: In step 2, the value range of the gas outburst pressure of the single hole in the tunnel is 0.08MPa~0.14MPa, and the value range of the measured pressure value inside the soil bin is 0.15MPa~0.3MPa.
5. A method for opening and changing cutters for pressure-maintaining and gas-transporting earth pressure balance shield machine according to claim 1, characterized in that: In step 2, the duration of pressure holding is in the range of 5 to 8 hours.