A slurry shield machine with a dual-circuit pressure control system

Abstract

The present invention provides a slurry balance shield machine with a dual-circuit pressure control system, which includes a shield body, a partition, a mud circuit, a compressed air circuit, a detection component, and a controller. A cutter disc is provided at the front end of the shield body, and the partition includes front and rear partitions. The front partition, the cutter disc, and the shield body form a mud and water bin, and the rear partition, the front partition, and the shield body form a bubble bin. A connecting hole connecting the mud and water bin and the bubble bin is provided at the bottom of the front partition. The detection component includes an air pressure sensor for detecting the pressure of the bubble bin. The controller controls the speed of the slurry inlet and outlet pumps and the opening and closing of the inlet and exhaust valves according to the detection value of the detection component. When the detection value exceeds the set range and the fluctuation value is less than the set value, the opening and closing of the inlet and exhaust valves are used to control the pressure. When the detection value exceeds the set range and the fluctuation value is greater than the set value, the speed of the slurry inlet and outlet pumps is also used to control the pressure. This not only achieves precise control of the slurry bin pressure, but also achieves rapid and large-scale adjustment of the slurry bin pressure, resulting in good excavation effect.

Description

Technical Field

[0001] The present invention relates to the technical field of shield machines, and in particular to a slurry shield machine with a dual-circuit pressure control system. Background Art

[0002] The slurry shield machine is a shield machine that balances the water and soil pressure at the face by controlling the pressure in the slurry tank. It is divided into two categories: direct and indirect. The direct slurry shield machine does not have a bubble tank. Its control principle is to equip the mud pump with a variable frequency motor, and use the variable frequency motor to adjust the mud pump speed to achieve the purpose of adjusting the mud pump flow and directly controlling the slurry tank pressure. Relatively speaking, it has a simple structure and low cost, and can quickly respond to sudden changes in face pressure. However, due to the hysteresis in the adjustment of the mud pump flow and the low adjustment accuracy, this pressure control method has its own problems. The phenomenon of serious overshoot occurs. When controlling the mud silo pressure, the fluctuation is large, and it takes a long time and multiple adjustments to stabilize the mud silo pressure within the set range. The indirect slurry balance shield machine is equipped with a bubble silo. The bubble silo and the mud silo are a kind of U-tube device. The pressure in the mud silo is indirectly controlled by controlling the bubble silo pressure. Although this method can achieve precise control of the mud silo pressure, the indirect control method is difficult to quickly and significantly adjust the mud silo pressure when the face pressure changes suddenly. When encountering special formations such as caves, it is difficult to ensure the stability of the formation. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a slurry shield machine with a dual-circuit pressure control system. The slurry shield machine can not only accurately control the slurry tank pressure, but also quickly and significantly adjust the slurry tank pressure to adapt to sudden changes in the face pressure, thereby ensuring the stability of the stratum during excavation and improving the excavation effect.

[0004] To achieve the above object, the technical solution adopted by the present invention is a slurry shield machine with a dual-circuit pressure control system, comprising:

[0005] A shield body, wherein a rotatable cutter disc is provided at the front end of the shield body;

[0006] A partition connected to the inner wall of the shield body and located behind the cutter disc, the partition including a front partition and a rear partition arranged at intervals, the space enclosed by the front partition, the cutter disc, and the shield body constituting a mud and water bin, and the space enclosed by the rear partition, the front partition, and the shield body constituting a bubble bin, and a connecting hole connecting the mud and water bin and the bubble bin is opened at the bottom of the front partition;

[0007] A mud circuit, comprising a slurry inlet pipe, a slurry discharge pipe, a slurry inlet pump, and a slurry discharge pump. One end of the slurry inlet pipe passes through the rear baffle and the front baffle and is connected to the mud-water bin. The other end of the slurry inlet pipe is connected to the mud-water separation station. One end of the slurry discharge pipe passes through the rear baffle and is aligned with the communicating hole. The other end of the slurry discharge pipe is connected to the mud-water separation station. The slurry inlet pump is connected in series to the slurry inlet pipe, and the slurry discharge pump is connected in series to the slurry discharge pipe.

[0008] A compressed air circuit, the compressed air circuit comprising an intake pipe, an exhaust pipe, an intake valve, and an exhaust valve, one end of the intake pipe passing through the rear baffle and communicating with the bubble chamber, the other end of the intake pipe communicating with an air source, one end of the exhaust pipe passing through the rear baffle and communicating with the bubble chamber, the other end of the exhaust pipe communicating with the outside atmosphere, the intake valve being connected in series to the intake pipe, and the exhaust valve being connected in series to the exhaust pipe;

[0009] A detection component, the detection component including an air pressure sensor for detecting the pressure of the bubble chamber;

[0010] A controller electrically connected to the detection component, the slurry feed pump, the slurry discharge pump, the air intake valve, and the air exhaust valve;

[0011] The controller can control the rotation speed of the slurry feed pump and the slurry discharge pump and the opening and closing of the air inlet valve and the air outlet valve according to the detection value of the detection component to achieve pressure control on the tunnel face. The control principle is as follows:

[0012] When the detection value of the air pressure sensor is lower than the lower limit of the set range, if the difference between the detection value and the lower limit of the set range is less than the set value, the controller pressurizes the bubble chamber by opening the air inlet valve and closing the air outlet valve; if the difference between the detection value and the lower limit of the set range is greater than the set value, the controller further pressurizes the bubble chamber by increasing the speed of the slurry feed pump and decreasing the speed of the slurry discharge pump until the detection value is higher than the lower limit of the set range;

[0013] When the detection value of the air pressure sensor is higher than the upper limit of the set range, if the difference between the detection value and the upper limit of the set range is less than the set value, the controller decompresses the bubble chamber by closing the air intake valve and opening the exhaust valve. If the difference between the detection value and the upper limit of the set range is greater than the set value, the controller also decompresses the bubble chamber by reducing the speed of the slurry feed pump and increasing the speed of the slurry discharge pump until the detection value is lower than the upper limit of the set range.

[0014] Preferably, the set value is 0.3 bar.

[0015] Preferably, the slurry shield machine further includes a liquid level gauge for detecting the liquid level in the bubble bin, a liquid replenishing pipeline for injecting liquid into the bubble bin, and a liquid replenishing valve connected in series to the liquid replenishing pipeline, and the liquid level gauge and the liquid replenishing valve are electrically connected to the controller;

[0016] When the liquid level value detected by the liquid level gauge is lower than the lower limit of the control range, the controller opens the liquid replenishing valve to increase the liquid level in the bubble bin until the liquid level value is higher than the lower limit of the control range. When the liquid level value detected by the liquid level gauge is higher than the upper limit of the control range, the controller closes the liquid replenishing valve and reduces the liquid level in the bubble bin by increasing the speed of the slurry discharge pump and reducing the speed of the slurry feed pump until the liquid level value is lower than the upper limit of the control range, thereby realizing the control of the liquid level in the bubble bin.

[0017] Further preferably, the control range is 53% to 57% of the total height of the bubble chamber.

[0018] Further preferably, the controller controls the bubble tank liquid level and the tunnel face pressure synchronously.

[0019] Further preferably, the detection component also includes a mud and water pressure sensor for detecting the pressure value in the mud and water bin. When there is a contradiction in the controller's control of the rotational speeds of the slurry discharge pump and the slurry feed pump based on the liquid level value and the detection value, if the detection value corresponds to the pressure value, the controller performs control based on the detection value; if the detection value does not correspond to the pressure value, the controller performs control based on the liquid level value.

[0020] Further preferably, the mud and water pressure sensor is connected to a first pipe, which passes through the rear partition and the front partition and is connected to the mud and water tank, and the first pipe is located at the center of the front partition; the air pressure sensor is connected to a second pipe, which passes through the rear partition and is connected to the bubble tank, and the second pipe is higher than the liquid level in the bubble tank.

[0021] Further preferably, the liquid level gauge extends in the up and down directions, the upper end of the liquid level gauge is higher than the liquid level surface in the bubble chamber, the lower end of the liquid level gauge extends downward into the liquid level surface and is higher than the upper edge of the connecting hole, and the part of the liquid level gauge located below the liquid level surface is not less than 40% of the total liquid level height of the bubble chamber.

[0022] Preferably, the air inlet pipe and the exhaust pipe are each provided with two paths, and the two paths are spaced apart in the up-down direction.

[0023] Preferably, a gate for opening or closing the communicating hole is provided at the bottom of the front partition.

[0024] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0025] The slurry balance shield machine with a dual-circuit pressure control system provided by the present invention combines the advantages of an indirect slurry balance shield machine and a direct slurry balance shield machine, and can switch between single-circuit pressure control and dual-circuit pressure control according to set conditions, thereby achieving precise control of the slurry bin pressure, improving the control accuracy of the face pressure, and achieving rapid and large-scale adjustment of the slurry bin pressure, adapting to sudden changes in the face pressure, and avoiding collapse when encountering terrain such as caves and hollows. It has a good stabilizing effect on the stratum during excavation, a good protection effect on the cutterhead, and a good excavation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural diagram of a preferred embodiment of the present invention.

[0027] Figure 2 yes Figure 1 A simplified schematic diagram of the system. The view direction is adjusted for easier observation.

[0028] Among them: 10. Shield; 11. Cutterhead; 21. Front baffle; 211. Connecting hole; 212. Gate; 22. Rear baffle; 23. Mud and water tank; 24. Bubble tank; 30. Mud circuit; 31. Slurry inlet pipe; 32. Slurry discharge pipe; 33. Slurry discharge pump; 34. Slurry inlet pump; 35. Return pipe; 36. Return valve group; 40. Compressed air circuit; 41. Inlet pipe; 42. Exhaust pipe; 43. Inlet valve; 44. Exhaust valve; 45. Air source; 50. Detection component; 51. Air pressure sensor; 511. Second pipeline; 52. Mud and water pressure sensor; 521. First pipeline; 60. Controller; 71. Liquid level meter; 72. Fluid supply pipeline; 73. Fluid supply valve. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0030] like Figure 1As shown, the slurry shield machine with a dual-circuit pressure control system provided by the present invention includes: a shield body 10, a partition, a mud circuit, a compressed air circuit, a detection component, and a controller 60, wherein the shield body 10 is cylindrical, and a rotatable cutter head 11 is provided at the front end of the shield body 10; the partition is connected to the inner wall of the shield body 10 and is located behind the cutter head 11, and the partition includes a front partition 21 and a rear partition 22 spaced apart along the front-to-back direction (the direction of the axial center line of the shield body 10), the space enclosed by the front partition 21, the cutter head 11, and the shield body 10 constitutes a mud and water bin 23, and the space enclosed by the rear partition 22, the front partition 21, and the shield body 10 constitutes a bubble bin 24, the width of the bubble bin 24 in the front-to-back direction is twice that of the mud and water bin 23, and a mud and water bin is provided at the bottom of the front partition 21. The communicating hole 211 of the water tank 23 and the bubble tank 24, and the bottom of the front partition 21 are also provided with a gate 212 for opening or closing the communicating hole 211; the mud circuit includes a slurry inlet pipe 31, a slurry discharge pipe 32, a slurry feed pump 34, and a slurry discharge pump 33. The front end of the slurry inlet pipe 31 passes through the rear partition 22 and the front partition 21 and is connected to the mud and water tank 23, and the rear end of the slurry inlet pipe 31 is connected to the mud and water separation station. The slurry inlet pipe 31 is a DN500 steel pipe, and the front end of the slurry discharge pipe 32 passes through the rear partition 22 and is aligned with the communicating hole 211. The rear end of the slurry discharge pipe 32 is connected to the mud and water separation station. The slurry discharge pipe 32 is a DN500 steel pipe. The slurry feed pump 34 is connected in series to the slurry inlet pipe 31. The slurry feed pump 34 includes a pump body and a frequency conversion motor for driving the pump body to operate. 33 is connected in series to the slurry discharge pipe 32. The slurry discharge pump includes a pump body and a variable frequency motor for driving the pump body; the compressed air circuit includes an intake pipe 41, an exhaust pipe 42, an intake valve 43, and an exhaust valve 44. The front end of the intake pipe 41 passes through the rear baffle 22 and is connected to the bubble bin 24, and the rear end of the intake pipe 41 is connected to the air source 45. The intake pipe 41 is a DN150 steel pipe, and the front end of the exhaust pipe 42 passes through the rear baffle 22 and is connected to the bubble bin 24. The rear end of the exhaust pipe 42 is connected to the outside atmosphere. The exhaust pipe 42 is a DN150 steel pipe. The intake pipe 41 and the exhaust pipe 42 are both provided with two routes, which are spaced apart in the upper and lower directions, one for use and one for backup, for easy maintenance. The intake valve 43 is connected in series to the intake pipe 41. The intake valve 43 is an electrically controlled valve. The exhaust valve 44 is connected in series to the exhaust pipe 42, and the exhaust valve 44 is also an electrically controlled valve; the detection component includes an air pressure sensor 51 for detecting the air pressure in the bubble chamber 24, and the air pressure sensor 51 is connected to the second pipe 511. The second pipe 511 passes through the rear partition 22 and is connected to the bubble chamber 24. The second pipe 511 is higher than the liquid level in the bubble chamber 24; the controller 60 is arranged behind the bubble chamber, and the controller 60 is electrically connected to the detection component, the slurry feed pump 34, the slurry discharge pump 33, the air intake valve 43, and the exhaust valve 44. The controller 60 can control the speed of the slurry feed pump 34 and the slurry discharge pump 33 and the opening and closing of the air intake valve 43 and the exhaust valve 44 according to the detection value of the detection component to achieve pressure control on the tunnel face. The control principle of the controller 60 is as follows:

[0031] When the detection value of the air pressure sensor 51 is lower than the lower limit of the set range, if the difference between the detection value and the lower limit of the set range is less than 0.3 bar, the controller 60 pressurizes the bubble chamber 24 by opening the air inlet valve 43 and closing the exhaust valve 44 to achieve precise control of the pressure of the mud and water chamber 23. If the difference between the detection value and the lower limit of the set range is greater than 0.3 bar, the controller 60 also pressurizes the bubble chamber 24 by increasing the speed of the slurry pump 31 and reducing the speed of the slurry pump 32.

[0032] Boosting to achieve rapid and substantial pressure adjustment of the mud and water tank 23 until the detected value is higher than the lower limit of the set range;

[0033] When the detection value of the air pressure sensor 51 is higher than the upper limit of the set range, if the difference between the detection value and the upper limit of the set range is less than 0.3 bar, the controller 60 depressurizes the bubble chamber 24 by closing the air intake valve 43 and opening the exhaust valve 44 to achieve precise control of the pressure of the mud and water chamber 23. If the difference between the detection value and the upper limit of the set range is greater than 0.3 bar, the controller 60 also depressurizes the bubble chamber 24 by reducing the speed of the slurry feed pump 34 and increasing the speed of the slurry discharge pump 33 to achieve rapid and large-scale adjustment of the pressure of the mud and water chamber 23 until the detection value is lower than the upper limit of the set range.

[0034] Such a setting can combine the advantages of indirect slurry balance shield machines and direct slurry balance shield machines, and thus switch between single-circuit pressure control and dual-circuit pressure control according to the set conditions, which not only realizes the precise control of the slurry tank pressure and improves the control accuracy of the face pressure, but also realizes the rapid and large-scale adjustment of the slurry tank pressure to adapt to the sudden change of the face pressure and avoid collapse when encountering caves, hollows and other terrains. It has a good stabilizing effect on the formation during excavation, a good protection effect on the cutterhead, and a good excavation effect.

[0035] It should be noted that the above setting range needs to be set comprehensively based on factors such as the depth of the excavation site, the water and soil pressure values ​​in the preliminary geological data, and the liquid level value in the bubble chamber.

[0036] In this embodiment, the slurry shield machine also includes a liquid level gauge 71 for detecting the liquid level height in the bubble bin 24, a liquid replenishing pipeline 72 for injecting liquid into the bubble bin 24, and a liquid replenishing valve 73 connected in series on the liquid replenishing pipeline 72. The liquid level gauge 71 and the liquid replenishing valve 73 are electrically connected to the controller 60; when the liquid level value detected by the liquid level gauge 71 is lower than the lower limit of the control range, the controller 60 opens the liquid replenishing valve 73 to raise the liquid level in the bubble bin 24 until the liquid level value is higher than the lower limit of the control range. When the liquid level value detected by the liquid level gauge 71 is higher than the upper limit of the control range, the controller 60 closes the liquid replenishing valve 73 and reduces the liquid level in the bubble bin 24 by increasing the speed of the slurry discharge pump 33 and reducing the speed of the slurry feed pump 3 until the liquid level value is lower than the upper limit of the control range, thereby realizing the control of the liquid level in the bubble bin 24. Preferably, the above-mentioned control range is 53% to 57% of the total height of the bubble bin 24.

[0037] In this embodiment, the controller 60 controls the liquid level in the bubble tank 24 and the face pressure simultaneously. Furthermore, the detection component also includes a mud and water pressure sensor 52 for detecting the pressure value in the mud and water tank 23. When there is a contradiction in the controller 60's control of the rotational speed of the slurry discharge pump 33 and the slurry feed pump 34 based on the liquid level value detected by the liquid level gauge 71 and the detection value of the air pressure sensor 51, if the detection value corresponds to the pressure value detected by the mud and water pressure sensor 52, the controller 60 controls based on the detection value; if the detection value does not correspond to the pressure value detected by the mud and water pressure sensor 52, the controller 60 controls based on the liquid level value. The advantage of this setting is that it can avoid erroneous operation caused by misjudgment of the air pressure sensor 51 or misjudgment of the liquid level gauge 71.

[0038] To ensure that the detection results of the mud and water pressure sensor 52 are broadly representative, in this embodiment, the mud and water pressure sensor 52 is connected to the first pipe 521, and the first pipe 521 passes through the rear partition 22 and the front partition 21 and is connected to the mud and water tank 23. The first pipe 521 is located in the center of the front partition 21.

[0039] In order to ensure the accuracy of the detection results of the liquid level gauge 71 and avoid misjudgment caused by changes in the liquid density in the bubble chamber 24 when the liquid (water) is replenished in the liquid replenishment pipeline 72, in this embodiment, the liquid level gauge 71 extends in the up and down directions, the upper end of the liquid level gauge 71 is higher than the liquid level surface in the bubble chamber 24, and the lower end of the liquid level gauge 71 extends downward into the liquid level surface and is higher than the upper edge of the connecting hole 211. The part of the liquid level gauge 71 below the liquid level surface is not less than 40% of the total height of the bubble chamber 24.

[0040] To facilitate the maintenance and control of the mud circuit, in this embodiment, the mud circuit also includes a return pipe 35 connecting the slurry inlet pipe 31 and the slurry discharge pipe 32 and a return valve group for controlling the communication between the return pipe 35 and the slurry inlet pipe 31 and the slurry discharge pipe 32.

[0041] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A slurry shield machine with a dual-circuit pressure control system, comprising: The front end is provided with a shield body with a rotatable cutter disc; A partition connected to the inner wall of the shield body and located behind the cutterhead, the partition includes a front partition and a rear partition arranged at intervals. The space enclosed by the front partition, the cutterhead, and the shield body constitutes a mud and water bin, and the space enclosed by the rear partition, the front partition, and the shield body constitutes a bubble bin. A connecting hole connecting the mud and water bin and the bubble bin is opened at the bottom of the front partition; A slurry circuit comprising a slurry inlet pipe, a slurry discharge pipe, a slurry inlet pump, and a slurry discharge pump. One end of the slurry inlet pipe passes through the rear baffle and the front baffle and is connected to the mud-water bin. The other end of the slurry inlet pipe is connected to the mud-water separation station. One end of the slurry discharge pipe passes through the rear baffle and is aligned with the communicating hole. The other end of the slurry discharge pipe is connected to the mud-water separation station. The slurry inlet pump is connected in series to the slurry inlet pipe, and the slurry discharge pump is connected in series to the slurry discharge pipe. A compressed air circuit comprising an intake pipe, an exhaust pipe, an intake valve, and an exhaust valve, wherein one end of the intake pipe passes through the rear baffle and is connected to the bubble chamber, and the other end of the intake pipe is connected to an air source. One end of the exhaust pipe passes through the rear baffle and is connected to the bubble chamber, and the other end of the exhaust pipe is connected to the outside atmosphere. The intake valve is connected in series to the intake pipe, and the exhaust valve is connected in series to the exhaust pipe. A detection assembly including an air pressure sensor for detecting the pressure in the bubble chamber; A controller electrically connected to the detection component, the slurry feed pump, the slurry discharge pump, the air inlet valve, and the air exhaust valve; A liquid level gauge for detecting the liquid level in the bubble chamber, a liquid replenishing pipeline for injecting liquid into the bubble chamber, and a liquid replenishing valve connected in series to the liquid replenishing pipeline, wherein the liquid level gauge and the liquid replenishing valve are electrically connected to the controller; Its characteristics are: The controller can control the speed of the slurry feed pump and the slurry discharge pump and the opening and closing of the air inlet valve and the air outlet valve according to the detection value of the detection component, thereby realizing pressure control on the tunnel face. The control principle is as follows: When the detection value of the air pressure sensor is lower than the lower limit of the set range, if the difference between the detection value and the lower limit of the set range is less than 0.3 bar, the controller pressurizes the bubble bin by opening the air inlet valve and closing the exhaust valve. If the difference between the detection value and the lower limit of the set range is greater than 0.3 bar, the controller further pressurizes the bubble bin by increasing the speed of the slurry feed pump and decreasing the speed of the slurry discharge pump until the detection value is higher than the lower limit of the set range; when the detection value of the air pressure sensor is higher than the upper limit of the set range, if the difference between the detection value and the upper limit of the set range is less than 0.3 bar, the controller depressurizes the bubble bin by closing the air inlet valve and opening the exhaust valve. If the difference between the detection value and the upper limit of the set range is greater than 0.3 bar, the controller further depressurizes the bubble bin by decreasing the speed of the slurry feed pump and increasing the speed of the slurry discharge pump until the detection value is lower than the upper limit of the set range; When the liquid level value detected by the liquid level meter is lower than the lower limit of the control range, the controller opens the liquid replenishing valve to increase the liquid level in the bubble bin until the liquid level value is higher than the lower limit of the control range. When the liquid level value detected by the liquid level meter is higher than the upper limit of the control range, the controller closes the liquid replenishing valve and reduces the liquid level in the bubble bin by increasing the speed of the slurry discharge pump and reducing the speed of the slurry feed pump until the liquid level value is lower than the upper limit of the control range, thereby realizing the control of the liquid level in the bubble bin.

2. The slurry shield machine with a dual-circuit pressure control system according to claim 1, characterized in that: The control range is 53% to 57% of the total height of the bubble chamber.

3. The slurry shield machine with a dual-circuit pressure control system according to claim 1, characterized in that: The controller controls the bubble tank liquid level and the tunnel face pressure synchronously.

4. The slurry shield machine with a dual-circuit pressure control system according to claim 3, characterized in that: The detection component also includes a mud and water pressure sensor for detecting the pressure value in the mud and water tank. When a contradiction occurs in the controller's control of the rotational speeds of the slurry discharge pump and the slurry feed pump based on the liquid level value and the detection value, if the detection value corresponds to the pressure value, the controller performs control based on the detection value; if the detection value does not correspond to the pressure value, the controller performs control based on the liquid level value.

5. The slurry shield machine with a dual-circuit pressure control system according to claim 4, characterized in that: The mud and water pressure sensor is connected to the first pipe, which passes through the rear partition and the front partition and is connected to the mud and water tank. The first pipe is located at the center of the front partition; the air pressure sensor is connected to the second pipe, which passes through the rear partition and is connected to the bubble tank. The second pipe is higher than the liquid level in the bubble tank.

6. The slurry shield machine with a dual-circuit pressure control system according to claim 1, characterized in that: The liquid level gauge extends in the up and down directions, the upper end of the liquid level gauge is higher than the liquid level surface in the bubble chamber, the lower end of the liquid level gauge extends downward into the liquid level surface and is higher than the upper edge of the connecting hole, and the part of the liquid level gauge located below the liquid level surface is not less than 40% of the total liquid level height of the bubble chamber.

7. The slurry shield machine with a dual-circuit pressure control system according to claim 1, characterized in that: The air inlet pipe and the exhaust pipe are both provided with two paths, and the two paths are spaced apart in the up-down direction.

8. The slurry shield machine with a dual-circuit pressure control system according to claim 1, characterized in that: A gate for opening or closing the communicating hole is provided at the bottom of the front partition.

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