Treatment method for emergency fault of slurry circulation system

Abstract

The invention discloses a processing method for an emergency fault of a slurry circulation system, and belongs to the technical field of tunnel shield construction, an alarm system sends out a first alarm signal after monitoring that the slurry circulation system has a first emergency fault, and a processing system starts a first processing process after receiving the first alarm signal; the alarm system sends out a second alarm signal after monitoring that the slurry circulation system has a second emergency fault, and the processing system starts a second processing process after receiving the second alarm signal; the alarm system sends out a third alarm signal after monitoring that the mud circulation system has the first emergency fault, and the processing system starts a third processing process after receiving the third alarm signal. According to the method, efficient and safe shield construction is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel shield construction, and in particular relates to a method for processing an emergency failure of a mud circulation system. Background Art

[0002] During the shield construction of a cross-sea tunnel in karst strata, emergency failures often occur in the mud circulation system due to the complex tunnel structure. The existing technology for handling emergency failures has a single method and cannot handle emergency failures in a timely manner. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a method for handling emergency failures of a mud circulation system, which adopts the following technical solutions:

[0004] A method for handling emergency failures of a mud circulation system is applied to the mud circulation system, wherein the mud circulation system comprises an alarm system, a processing system, a bypass ball valve, a slurry discharge pump, a slurry feed pump, a slurry discharge relay pump and a slurry discharge pipeline;

[0005] The alarm system sends out a first alarm signal after detecting a first emergency failure of the mud circulation system, and the processing system starts a first processing process after receiving the first alarm signal;

[0006] The alarm system sends out a second alarm signal after detecting a second emergency failure of the mud circulation system, and the processing system starts a second processing process after receiving the second alarm signal;

[0007] The alarm system sends out a third alarm signal after detecting a third emergency failure of the mud circulation system, and the processing system starts a third processing process after receiving the third alarm signal.

[0008] Furthermore, the first processing step includes:

[0009] Determine whether the slurry feed pump can be restarted:

[0010] If not, it is determined that the slurry feed pump is the first fault, then the rotation speed of the slurry discharge pump and the slurry discharge relay pump is reduced, and then the bypass hydraulic ball valve is opened, and the normal excavation mode is switched to the bypass mode and the circulation is stopped;

[0011] If yes, continue to use the processing system to perform the first processing process, restart the slurry feed pump, adjust the speed of the slurry feed pump to meet the slurry feed amount, and simultaneously reduce the speeds of the slurry discharge pump and the slurry discharge relay pump;

[0012] The continuing to use the processing system to perform the first processing process includes:

[0013] Determine whether the slurry pump can be restarted:

[0014] If not, it is determined that the slurry discharge pump is the second fault, and the speed of the slurry feed pump and the slurry discharge relay pump is reduced, and then the bypass hydraulic ball valve is opened to switch to the bypass mode;

[0015] If yes, continue to use the processing system to perform the first processing process, restart the slurry discharge pump, reduce the rotation speed of the slurry discharge relay pump, and reduce the rotation speed of the slurry feed pump;

[0016] The continuing to use the processing system to perform the first processing process includes:

[0017] Determine whether the slurry discharge relay pump can be restarted:

[0018] If not, it is determined that the slurry discharge relay pump is the third fault, and the speed of the slurry feed pump and the slurry discharge pump is reduced and then the bypass hydraulic ball valve is opened to switch to the bypass mode.

[0019] Furthermore, the second processing step includes:

[0020] When the second signal is detected, the inlet pressures of the secondary crusher, the diverter box, and the slurry discharge pump at the current moment are recorded as the first pressure value;

[0021] Recording the inlet pressures of the secondary crusher, the diverter box, and the slurry discharge pump at a time after the first time as a second pressure value;

[0022] Recording the inlet pressures of the secondary crusher, the diverter box, and the slurry discharge pump after the second moment as the third pressure value;

[0023] Determine whether the second pressure value is less than the first pressure value and the third pressure value is less than the second pressure value:

[0024] If so, it is determined that the slurry discharge pipeline at the grid or from the grid to the secondary crusher is the fourth fault, and the speed of the slurry discharge pump is reduced, the speed of the slurry feed pump is reduced, and the speed of the slurry discharge relay pump is reduced, and then the bypass ball valve is opened to switch to the bypass mode; in the bypass mode, the speed of the slurry feed pump is increased, and after the speed of the slurry discharge pump is reduced, the pressure on the top of the mud and water bin is backwashed, and the two arms of the secondary crusher are kept open during backwashing. After backwashing, the secondary crusher performs a clamping action, and the speeds of the slurry feed pump and the slurry discharge pump are adjusted, and the excavation mode is switched from the bypass mode;

[0025] If not, continue to use the processing system to perform the second processing process;

[0026] The continuing to use the processing system to perform the second processing process includes:

[0027] Determine whether the second pressure value is less than the first pressure value and the third pressure value is greater than the second pressure value:

[0028] If so, it is determined that the grid and the slurry discharge pipeline from the grid to the secondary crusher are the fifth fault, and the secondary crusher is adjusted to perform high-frequency operation, and the circulation mode is adjusted to increase the slurry intake into the air cushion bin.

[0029] Furthermore, the third processing step includes:

[0030] Determine whether the mud door is blocked:

[0031] If not, stop excavation and adjust the slurry feeding and discharging mode, increase the slurry feeding amount in the air cushion chamber and observe the secondary crusher stroke to suspend the accumulated slag in the air cushion chamber, and perform a small cycle of slag discharging in the air cushion chamber; after the crusher stroke is completely normal, adjust the slurry feeding mode to increase the slurry feeding amount in the mud and water chamber and rotate the cutter head to observe the torque fluctuation of the cutter head, switch and clean the air cushion chamber and mud and water chamber, keep the mud door flushing ball valve open during this process to ensure that the mud door is not blocked, and resume excavation after the torque fluctuation range of the cutter head is stable;

[0032] If so, it is determined that the mud door is blocked as the sixth fault. Stop excavation to clean the air cushion chamber, adjust the slurry feeding mode to cut off the slurry feeding into the mud and water chamber.

[0033] Beneficial effects:

[0034] The method for handling emergency failures of a mud circulation system provided by the present invention can timely handle the location where the emergency failure occurs by analyzing the causes of the emergency failures in the circulation system and formulating corresponding countermeasures, thereby forming a systematic emergency failure handling system, so that the emergency failures are effectively handled, the ability to respond to emergencies is improved, and the efficient and safe progress of shield construction is ensured, minimizing casualties and property losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a flow chart of a method for handling an emergency failure of a mud circulation system. DETAILED DESCRIPTION

[0036] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below.

[0037] Example 1

[0038] Reference Figure 1, a method for handling emergency failures of a mud circulation system, applied to the mud circulation system, the mud circulation system comprising an alarm system, a bypass ball valve, a slurry discharge pump, a slurry feed pump, a slurry discharge relay pump and a slurry discharge pipeline;

[0039] The alarm system sends out a first alarm signal after detecting a first emergency failure of the mud circulation system, and the processing system starts a first processing process after receiving the first alarm signal;

[0040] The alarm system sends out a second alarm signal after detecting a second emergency failure of the mud circulation system, and the processing system starts a second processing process after receiving the second alarm signal;

[0041] The alarm system sends out a third alarm signal after detecting a third emergency failure of the mud circulation system, and the processing system starts a third processing process after receiving the third alarm signal.

[0042] Through the above technical solution, the alarm system detects the alarm signal sent out after an emergency failure occurs in the mud circulation system, and the processing system starts the processing process after receiving the alarm signal.

[0043] In this embodiment, the first processing step includes:

[0044] Determine whether the slurry pump can be restarted:

[0045] If not, it is determined that the slurry pump is the first fault, then reduce the speed of the slurry discharge pump and the slurry discharge relay pump, open the bypass hydraulic ball valve, switch from the normal excavation mode to the bypass mode, and stop the circulation;

[0046] If yes, continue to use the processing system to perform the first processing process, restart the slurry feed pump, and adjust the speed of the slurry feed pump to meet the slurry feed volume, and simultaneously reduce the speed of the slurry discharge pump and the slurry discharge relay pump;

[0047] Continue using the treatment system to perform the first treatment process, including:

[0048] Determine whether the slurry pump can be restarted:

[0049] If not, determine that the slurry discharge pump is the second fault, reduce the speed of the slurry feed pump and the slurry discharge relay pump, and then open the bypass hydraulic ball valve to switch to the bypass mode;

[0050] If yes, continue to use the processing system to perform the first processing process, restart the slurry discharge pump, reduce the speed of the slurry discharge relay pump, and reduce the speed of the slurry feed pump;

[0051] Continue using the treatment system to perform the first treatment process, including:

[0052] Determine whether the slurry discharge relay pump can be restarted:

[0053] If not, determine that the slurry discharge relay pump is the third fault, reduce the speed of the slurry feed pump and the slurry discharge pump, and then open the bypass hydraulic ball valve to switch to the bypass mode.

[0054] In this embodiment, the second processing step includes:

[0055] When the second signal is detected, the inlet pressure of the secondary crusher, the diverter box, and the slurry discharge pump at the current moment is recorded as the first pressure value;

[0056] Record the inlet pressure of the secondary crusher, the diverter box, and the slurry discharge pump at the time after the first time as the second pressure value;

[0057] Record the inlet pressure of the secondary crusher, the diverter box, and the slurry discharge pump after the second moment as the third pressure value;

[0058] Determine whether the second pressure value is less than the first pressure value and the third pressure value is less than the second pressure value:

[0059] If so, determine that the slurry discharge pipeline at the grid or from the grid to the secondary crusher is the fourth fault, reduce the speed of the slurry discharge pump, reduce the speed of the slurry feed pump, reduce the speed of the slurry discharge relay pump, and then open the bypass ball valve to switch to bypass mode; in bypass mode, increase the speed of the slurry feed pump, reduce the speed of the slurry discharge pump, and then backwash the top pressure of the mud and water bin. Keep the two arms of the secondary crusher open during backwashing. After backwashing, the secondary crusher performs a clamping action, adjust the speed of the slurry feed pump and the slurry discharge pump, and switch from bypass mode to excavation mode;

[0060] If not, continue to use the processing system to perform the second processing process;

[0061] Continue using the processing system for a second processing step, including:

[0062] Determine whether the second pressure value is less than the first pressure value and the third pressure value is greater than the second pressure value:

[0063] If so, determine that the grid and the slurry discharge pipeline from the grid to the secondary crusher are the fifth fault. Adjust the secondary crusher to perform high-frequency operation, and at the same time adjust the circulation mode to increase the slurry intake into the air cushion bin.

[0064] In this embodiment, the third processing step includes:

[0065] Determine whether the mud door is blocked:

[0066] If not, stop excavation and adjust the slurry feeding and discharging mode, increase the slurry feeding amount in the air cushion chamber and observe the secondary crusher stroke to suspend the accumulated slag in the air cushion chamber, and perform a small cycle of slag discharging in the air cushion chamber; after the crusher stroke is completely normal, adjust the slurry feeding mode to increase the slurry feeding amount in the mud and water chamber and rotate the cutter head to observe the torque fluctuation of the cutter head, switch and clean the air cushion chamber and mud and water chamber, keep the mud door flushing ball valve open during this process to ensure that the mud door is not blocked, and resume excavation after the torque fluctuation range of the cutter head is stable;

[0067] If so, it is determined that the mud door is blocked as the sixth fault. Stop excavation to clean the air cushion chamber, adjust the slurry feeding mode to cut off the slurry feeding into the mud and water chamber.

[0068] Example 2

[0069] This embodiment is based on the embodiment 1: the mud circulation system includes an alarm system, a processing system, a bypass ball valve, a slurry discharge pump, a slurry feed pump, a slurry discharge relay pump and a slurry discharge pipeline; the first processing process includes:

[0070] Slurry pump failure:

[0071] Restart the slurry feed pump promptly to adjust the speed to meet the slurry feed volume, and simultaneously reduce the speed of the slurry discharge pump and slurry discharge relay pump to prevent the liquid level in the air cushion chamber from dropping too quickly, causing instability of the under-pressure tunnel face. At the same time, cooperate with the mechanics to troubleshoot the fault according to the alarm history records;

[0072] If the slurry pump cannot be restarted in time, it is necessary to reduce the speed of the slurry discharge pump and the slurry discharge relay pump, open the bypass hydraulic ball valve, switch from the normal excavation mode to the bypass mode, stop the circulation, and troubleshoot the fault;

[0073] Slurry pump failure:

[0074] If the slurry discharge pump can be restarted in time, it is necessary to appropriately reduce the speed of the slurry discharge relay pump to prevent the pump from sucking air and causing the slurry discharge pipeline to shake. At the same time, reduce the speed of the slurry feed pump to prevent the explosion of the warehouse and the excessive pressure caused by the rapid rise of the liquid level in the warehouse, resulting in the occurrence of the tunnel face breakdown accident;

[0075] If the slurry discharge pump cannot be restarted in time, it is necessary to reduce the speed of the slurry feed pump and the slurry discharge relay pump and then open the bypass hydraulic ball valve to switch to the bypass mode. Since local slag accumulation may block the pipe at the slurry discharge pump, water hammer may occur at the inlet section of the slurry discharge pump if the speed of the slurry feed pump and the slurry discharge relay pump is not reduced to switch to the bypass mode. Before switching to the bypass mode, reduce the speed of the slurry feed pump to prevent explosion, and reduce the speed of the slurry discharge relay pump to prevent air suction;

[0076] Slurry discharge relay pump failure:

[0077] If the slurry discharge relay pump can be restarted in time, it is necessary to appropriately reduce the slurry discharge pump to prevent the pump outlet pressure from being too high, reduce the speed of the slurry discharge relay pump to prevent the pump from sucking air and causing the slurry discharge pipeline to shake seriously, and at the same time reduce the speed of the slurry inlet pump to prevent the explosion of the warehouse and the rapid rise of the liquid level in the warehouse, resulting in excessive pressure and the occurrence of a tunnel face breakdown accident;

[0078] If the slurry discharge relay pump cannot be restarted in time, it is necessary to reduce the speed of the slurry feed pump and the slurry discharge pump, then open the bypass hydraulic ball valve to switch to the bypass mode. Since local slag accumulation and pipe blockage may occur at the inlet and outlet sections of the slurry discharge relay pump, water hammer may occur at the inlet and outlet sections of the slurry discharge relay pump if the speed of the slurry feed pump and the slurry discharge pump is not reduced to switch to the bypass mode. Before switching to the bypass mode, reduce the speed of the slurry feed pump to prevent explosion, and reduce the speed of the slurry discharge pump to prevent excessive pressure at the pump outlet;

[0079] The second processing step includes:

[0080] Blockage at the grille:

[0081] If the inlet pressure of the secondary crusher, diverter box, and slurry pump drops rapidly, it can be determined that the slurry discharge pipeline at the grille or from the grille to the secondary crusher is blocked. According to experience, this situation is generally caused by large rocks blocking the grille. The speed of the slurry discharge pump should be quickly reduced to prevent air suction and the blockage should be violently cleared under the high pressure difference between the inlet and outlet of the slurry discharge pump to cause water hammer. At the same time, the speed of the slurry feed pump should be appropriately reduced to prevent warehouse explosion, and the speed of the slurry discharge relay pump should be reduced to prevent air suction. Then, the bypass hydraulic ball valve should be opened to switch to the bypass mode. In the bypass mode, the speed of the slurry feed pump should be increased, and the speed of the slurry discharge pump should be reduced. Pay close attention to the pressure of the slurry feed and discharge pipelines, the liquid level in the bin, and the pressure on the top of the mud and water bin for backwashing. Keep the two arms of the crusher open during backwashing. After backwashing, the crusher performs a clamping action, and then adjust the speed of the slurry feed and discharge pumps to switch from the bypass mode to the excavation mode.

[0082] The slurry discharge pipeline from the grille to the secondary crusher is blocked:

[0083] If the inlet pressure of the secondary crusher, diverter box and slurry pump fluctuates severely, and the current of the secondary crusher is stable (the stable current determines that there are no large stones and the secondary crusher is not crushing at high load), and the pressure at the three places fluctuates and decreases slowly, it can be determined that the grid and the slurry discharge pipeline from the grid to the secondary crusher are blocked by slag accumulation. At this time, adjust the crusher to perform high-frequency action, and at the same time adjust the circulation mode to increase the slurry intake in the air cushion bin to suspend the slag at the bottom of the air cushion bin and reduce the laminar flow in the slurry discharge pipeline from the grid to the secondary crusher for steady flow. This process is generally completed by closing the upper flushing ball valve and appropriately increasing the speed of the slurry pump. If the grid and the slurry discharge pipeline cannot be unblocked, backwashing is performed according to the blockage at the grid;

[0084] Any slurry inlet pipe is blocked:

[0085] Through the flow meter display of the slurry inlet pipeline and the increase of slurry inlet pressure, it is determined that the pipe is blocked and the bypass mode is used to ensure that the slurry discharge pipeline does not carry slag. The ball valve of the blocked pipeline is kept open for back suction and appropriate pressurization, and the pipeline is unblocked by multiple pressure difference switching.

[0086] The third processing step includes:

[0087] Slag accumulates in the air cushion bin but the mud door is not blocked:

[0088] Stop excavation and adjust the slurry feeding and discharging mode, increase the slurry feeding amount in the air cushion chamber and observe the crusher stroke to suspend the accumulated slag in the air cushion chamber, and perform a small cycle of slag discharging in the air cushion chamber. After the crusher stroke is completely normal, adjust the slurry feeding mode to increase the slurry feeding amount in the mud and water chamber, rotate the cutter head and observe the torque fluctuation of the cutter head, switch and clean the air cushion chamber and mud and water chamber, and keep the mud door flushing ball valve open during this process to ensure that the mud door is not blocked. Resume excavation after the torque fluctuation range of the cutter head is basically stable;

[0089] Mud door plugging:

[0090] In this case, both the air cushion bin and the mud and water bin are seriously accumulated with slag, and the cutterhead may not be able to rotate due to excessive torque. Stop excavation to clean the air cushion bin, adjust the slurry feeding mode to cut off the slurry feeding of the mud and water bin to prevent excessive top pressure of the mud and water bin. During this process, ensure that the slurry feeding pipeline in the air cushion bin is not blocked. If the slurry feeding pipeline is blocked, switch to the bypass mode for back suction and appropriate pressurization to dredge the slurry feeding pipeline. After dredging, adjust the slurry feeding pump speed when cutting the bin to observe the main slurry feeding pipe pressure to prevent the flushing pipeline in the air cushion bin from being blocked again, resulting in the main slurry feeding pipe being pressurized. After the bin is cut, observe the slurry discharge pipeline pressure during the slag discharge process. If the slurry discharge pipe in front of the grid or the slurry discharge pump is blocked, switch to the bypass mode in time for backwashing. Try this process many times. During the process, keep the mud gate flushing pipeline ball valve open, and pay attention to whether the mud gate flushing pipe is unblocked.

[0091] The direct discharge mode is used to clean the accumulated slag in the mud and water bin. During this process, the upper flushing pipeline is kept filled with slurry. In the direct discharge mode of the mud and water bin, there is no action of the crocodile crusher, so attention should be paid to pipe blocking and the top pressure of the mud and water bin should be observed to prevent the mismatch of the inlet and discharge slurry and unstable top pressure and the collapse of the face again. After the direct discharge pipe is blocked, the mud and water bin is properly backwashed to suspend the accumulated slag in the mud and water bin and then circulate the slag for discharge again. This process is tried many times. During the process, the ball valve of the mud gate flushing pipeline is kept open, and attention should be paid to whether the mud gate flushing pipe is unblocked.

[0092] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for handling emergency failures of a mud circulation system, applied to a mud circulation system, wherein the mud circulation system comprises an alarm system, a processing system, a bypass ball valve, a slurry discharge pump, a slurry feed pump, a slurry discharge relay pump and a slurry discharge pipeline, characterized in that: The alarm system sends out a first alarm signal after detecting a first emergency failure of the mud circulation system, and the processing system starts a first processing process after receiving the first alarm signal; The alarm system sends out a second alarm signal after detecting a second emergency failure of the mud circulation system, and the processing system starts a second processing process after receiving the second alarm signal; The alarm system sends out a third alarm signal after detecting a third emergency failure of the mud circulation system, and the processing system starts a third processing process after receiving the third alarm signal.

2. The method for handling emergency failure of a mud circulation system according to claim 1, characterized in that: The first processing step includes: Determine whether the slurry feed pump can be restarted: If not, it is determined that the slurry feed pump is the first fault, then the rotation speed of the slurry discharge pump and the slurry discharge relay pump is reduced, and then the bypass hydraulic ball valve is opened, and the normal excavation mode is switched to the bypass mode and the circulation is stopped; If yes, continue to use the processing system to perform the first processing process, restart the slurry feed pump, adjust the speed of the slurry feed pump to meet the slurry feed amount, and simultaneously reduce the speeds of the slurry discharge pump and the slurry discharge relay pump; The continuing to use the processing system to perform the first processing process includes: Determine whether the slurry pump can be restarted: If not, it is determined that the slurry discharge pump is the second fault, and the speed of the slurry feed pump and the slurry discharge relay pump is reduced, and then the bypass hydraulic ball valve is opened to switch to the bypass mode; If yes, continue to use the processing system to perform the first processing process, restart the slurry discharge pump, reduce the rotation speed of the slurry discharge relay pump, and reduce the rotation speed of the slurry feed pump; The continuing to use the processing system to perform the first processing process includes: Determine whether the slurry discharge relay pump can be restarted: If not, it is determined that the slurry discharge relay pump is the third fault, and the speed of the slurry feed pump and the slurry discharge pump is reduced and then the bypass hydraulic ball valve is opened to switch to the bypass mode.

3. The method for handling emergency failure of a mud circulation system according to claim 1, characterized in that: The second processing step includes: When the second signal is detected, the inlet pressures of the secondary crusher, the diverter box, and the slurry discharge pump at the current moment are recorded as the first pressure value; Recording the inlet pressures of the secondary crusher, the diverter box, and the slurry discharge pump at a time after the first time as a second pressure value; Recording the inlet pressures of the secondary crusher, the diverter box, and the slurry discharge pump after the second moment as the third pressure value; Determine whether the second pressure value is less than the first pressure value and the third pressure value is less than the second pressure value: If so, it is determined that the slurry discharge pipeline at the grid or from the grid to the secondary crusher is the fourth fault, and the speed of the slurry discharge pump is reduced, the speed of the slurry feed pump is reduced, and the speed of the slurry discharge relay pump is reduced, and then the bypass ball valve is opened to switch to the bypass mode; in the bypass mode, the speed of the slurry feed pump is increased, and after the speed of the slurry discharge pump is reduced, the pressure on the top of the mud and water bin is backwashed, and the two arms of the secondary crusher are kept open during backwashing. After backwashing, the secondary crusher performs a clamping action, and the speeds of the slurry feed pump and the slurry discharge pump are adjusted, and the excavation mode is switched from the bypass mode; If not, continue to use the processing system to perform the second processing process; The continuing to use the processing system to perform the second processing process includes: Determine whether the second pressure value is less than the first pressure value and the third pressure value is greater than the second pressure value: If so, it is determined that the grid and the slurry discharge pipeline from the grid to the secondary crusher are the fifth fault, and the secondary crusher is adjusted to perform high-frequency operation, and the circulation mode is adjusted to increase the slurry intake into the air cushion bin.

4. The method for handling emergency failure of a mud circulation system according to claim 1, characterized in that: The third processing step includes: Determine whether the mud door is blocked: If not, stop excavation and adjust the slurry feeding and discharging mode, increase the slurry feeding amount in the air cushion chamber and observe the secondary crusher stroke to suspend the accumulated slag in the air cushion chamber, and perform a small cycle of slag discharging in the air cushion chamber; after the crusher stroke is completely normal, adjust the slurry feeding mode to increase the slurry feeding amount in the mud and water chamber and rotate the cutter head to observe the torque fluctuation of the cutter head, switch and clean the air cushion chamber and mud and water chamber, keep the mud door flushing ball valve open during this process to ensure that the mud door is not blocked, and resume excavation after the torque fluctuation range of the cutter head is stable; If so, it is determined that the mud door is blocked as the sixth fault. Stop excavation to clean the air cushion chamber, adjust the slurry feeding mode to cut off the slurry feeding into the mud and water chamber.

Images