A tunnel boring machine with a cutterhead that prevents mud cake formation.

Abstract

This invention relates to the field of tunnel boring machine (TBM) technology and discloses a TBM with a cutterhead anti-mud cake formation system. The flushing system of this invention operates in advance, maintaining a certain pressure at both the front and rear ends of the cutterhead. This pressure ensures pressure during tunneling, preventing the front end of the cutterhead from collapsing while also reducing the forward pressure on the cutters and minimizing heat buildup and friction loss. During tunneling, the system flushes both the cutting face and the back of the cutterhead from multiple directions, providing multi-directional impact and effectively flushing excavated soil off the cutting face and cutters. This effectively prevents mud cake formation on the cutting face and cutters, preventing soil adhesion and ensuring continued tunneling, thus maximizing tunneling efficiency and speed.

Description

Technical Field

[0001] This invention relates to the field of tunnel boring machine technology, specifically to a tunnel boring machine with a cutterhead designed to prevent mud cake formation. Background Technology

[0002] A tunnel boring machine (TBM) is a type of tunnel boring machine that uses the shield tunneling method. The shield tunneling method involves the TBM simultaneously constructing (laying) the tunnel's "shield" (referring to supporting segments) while excavating, which differs from open-cut construction methods. Internationally, TBMs can also be used in rock formations in a broader sense, but this is distinct from open-cut (non-shield tunneling) TBMs. In my country, however, TBMs used in soft soil formations are conventionally referred to as (narrowly defined) shield tunneling machines, while those used in rock formations are called (narrowly defined) TBMs. Based on their working principles, TBMs are generally classified into hand-dug shields, compression shields, semi-mechanized shields (local pneumatic, global pneumatic), and mechanical shields (open-cut shields, pneumatic shields, slurry-pressurized shields, earth pressure balance shields, hybrid shields, and irregular-shaped shields).

[0003] The basic working principle of a tunnel boring machine (TBM) is that a cylindrical steel assembly advances along the tunnel axis while excavating the soil. The shell of this cylindrical assembly, the shield, provides temporary support for the excavated, unlined tunnel section, withstands the pressure of the surrounding soil layers, and sometimes also withstands groundwater pressure and keeps groundwater out. Excavation, soil removal, and lining operations are carried out under the protection of the shield.

[0004] During tunnel boring machine (TBM) construction, TBMs have a certain degree of geological adaptability. However, improper selection of the TBM type, complex geological conditions, or incorrect operator methods can all lead to low efficiency. In practical engineering applications, when excavating complex strata such as cohesive soil, various types of mudstone, and strongly weathered soft rock, the cutterhead grid is easily clogged with clay. This makes it difficult for slurry to flow from the cutterhead to the excavation chamber. After repeated compaction, the slurry easily forms mud cakes on the cutterhead surface, further clogging the cutterhead grid. If these mud cakes are not cleaned promptly, a vicious cycle can occur. Once the thickness of the mud cake exceeds the height of the excavating cutterhead, the cutterhead will lose its excavation capacity, severely impacting the TBM construction.

[0005] Existing shield tunneling machine mud-proof systems include flushing pipes. High-pressure water or mud is sprayed from the flushing port through the flushing pipes to flush the mud on the cutterhead and soil chamber, thereby improving the fluidity of the excavated soil in the cutterhead and soil chamber and preventing the formation of mud cakes on the cutterhead and soil chamber. However, the above-mentioned flushing effect cannot be fully applied to the surface layer of the cutterhead and mud chamber, making it difficult to effectively prevent the formation of mud cakes on the cutterhead's excavation face and the cutting tools.

[0006] No effective solutions have yet been proposed to address the problems in the relevant technologies. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a tunnel boring machine with a cutterhead designed to prevent mud cake formation.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0009] A tunnel boring machine (TBM) with a cutterhead designed to prevent mud cake formation includes a cutterhead. The cutterhead's excavation face is provided with several main beams and several secondary beams, each with several cutting tools on its surface. The main beams and secondary beams are evenly spaced on the cutterhead's excavation face. Each main beam and secondary beam has muck openings on both sides. A slurry chamber is located on the back of the cutterhead. During the excavation process, the generated muck flows radially along the cutterhead and enters the slurry chamber through the muck openings. The machine also includes a flushing system comprising a central panel flushing unit, a central opening flushing unit, a central back flushing unit, and a central transverse flushing unit. The central panel flushing unit and the central opening flushing unit flush the excavation face of the cutterhead, while the central back flushing unit and the central transverse flushing unit flush the back of the cutterhead. The slurry chamber is located away from the cutterhead. An air cushion chamber is provided on one side of the tunnel. A mud gate is provided between the mud-water chamber and the air cushion chamber to isolate them. A mud-water agitator is provided at the bottom of the air cushion chamber. A slurry discharge pipe is provided at the bottom of the air cushion chamber and on the side away from the air cushion chamber. A grid is provided at the end of the slurry discharge pipe near the mud-water agitator. The mud-water agitator is used to agitate the bottom of the air cushion chamber. The slurry discharge pipe is connected to a slurry discharge pump. The grid is used to screen the particle size of the excavated soil entering the slurry discharge pipe so that the particle size of the excavated soil passing through the grid can meet the power requirements of the slurry discharge pump. The tunnel also includes a mud circulation system. The mud-water collected from the slurry discharge pipe can be treated and supplied to the flushing system, the air cushion chamber pressure holding system, and the advanced grouting system. The air cushion chamber pressure holding system is used to maintain the mud level inside the air cushion chamber. The advanced grouting system is used to reinforce the geology of the cutterhead excavation face.

[0010] Preferably, the central panel flushing unit is located at the center of the cutterhead's excavation face, and the central panel flushing unit has four evenly distributed flushing paths; the central opening flushing unit is located outside the central panel flushing unit, and the central opening flushing unit includes four front flushing openings, each of which has two mutually perpendicular flushing paths; the central panel flushing unit and the central opening flushing unit together have 12 flushing paths flushing the cutterhead's excavation face, and the included angle between any two adjacent flushing paths is equal.

[0011] Preferably, the central back flushing unit includes two back vertical flushing openings, each of which is perpendicular to the back of the cutter head; the central transverse flushing unit includes two back transverse flushing pipes, each of which has two back transverse flushing openings in opposite directions, each of which is parallel to the back of the cutter head.

[0012] Preferably, the mud circulation system includes a discharge pump, a relay pump, an equalization tank, a sedimentation tank, a separation device, and a feed pump. The discharge pump is used to extract mud from the discharge pipe and feed the mud into the equalization tank, sedimentation tank, and separation device for processing via the relay pump. The processed slurry is then supplied to the flushing system, the air cushion chamber pressure-maintaining system, and the pre-grouting system via the feed pump.

[0013] Preferably, the mud gate includes a front gate, and hydraulic rods are provided on both sides of the front gate for controlling the opening and closing of the front gate. Mud gate flushing nozzles are also provided on both sides of the side of the mud gate located in the mud tank. The mud gate flushing nozzles are connected to the mud inlet pump of the mud circulation system, and the mud gate flushing nozzles can flush the side of the front gate located in the mud tank.

[0014] Preferably, the mud-water mixer includes a stirring impeller, a drive motor, and a wear-resistant outer cylinder. The wear-resistant outer cylinder penetrates and is fixed inside the wall of the air cushion chamber. The stirring impeller is rotatably connected to the wear-resistant outer cylinder. The output shaft of the drive motor penetrates inside the wear-resistant outer cylinder and is fixed to the stirring impeller. The drive motor can output power to drive the stirring impeller to rotate and stir the bottom of the air cushion chamber.

[0015] Preferably, the stirring impeller includes several stirring blades, which can break up the slag at the bottom of the air cushion chamber when rotating; the grid is set at the bottom of the side wall of the air cushion chamber away from the mud chamber, and the grid flushing nozzles are also provided on both sides of the side of the grid inside the air cushion chamber. The grid flushing nozzles are connected to the slurry pump of the mud circulation system, and the grid flushing nozzles can flush the side of the grid inside the air cushion chamber.

[0016] Preferably, the air cushion chamber pressure-maintaining system includes a liquid pressure-maintaining nozzle and a gas pressure-maintaining nozzle. The liquid pressure-maintaining nozzle is located in the middle of the air cushion chamber and is connected to the slurry pump of the mud circulation system. The gas pressure-maintaining nozzle is connected to a pressure-maintaining gas tank. The air cushion chamber pressure-maintaining system can supply slurry to the inside of the air cushion chamber through the liquid pressure-maintaining nozzle and supply compressed air to the inside of the air cushion chamber through the gas pressure-maintaining nozzle to maintain the internal pressure of the air cushion chamber.

[0017] Preferably, the advanced grouting system includes a plurality of circumferential grouting holes and a plurality of horizontal grouting holes. The circumferential grouting holes are evenly distributed around the circumference of the shield shell of the tunnel boring machine, and the horizontal grouting holes are located on the surface of the pressure baffle of the shield body of the tunnel boring machine. The plurality of circumferential grouting holes and the plurality of horizontal grouting holes can be connected to a mud pump respectively, and the mud pump provides mixed mud to the plurality of circumferential grouting holes and the plurality of horizontal grouting holes respectively.

[0018] Preferably, the plurality of circumferential grouting holes and the plurality of horizontal grouting holes can also be connected to the grout pump of the mud circulation system, and the grout pump can respectively supply the treated grout to the plurality of circumferential grouting holes and the plurality of horizontal grouting holes.

[0019] Compared with the prior art, the present invention provides a tunnel boring machine with a cutterhead anti-mud cake formation feature, which has the following characteristics:

[0020] Beneficial effects:

[0021] 1. In this type of tunnel boring machine with anti-mud cake on the cutterhead, the flushing system is pre-operated, maintaining a certain pressure at both the front and rear ends of the cutterhead. This pressure ensures pressure during tunneling, preventing the front end of the cutterhead from collapsing while also reducing the forward pressure on the cutters and decreasing heat accumulation during use, thus reducing frictional losses. Since each main beam and secondary beam has muck openings on both sides, the muck generated by the cutters breaking up the strata during cutterhead rotation can flow radially along the cutterhead and enter the slurry chamber through these openings. During tunneling, the central panel flushing unit and the central opening flushing unit are used to flush the tunneling face of the cutterhead. Both the flushing unit and the central transverse flushing unit are used to flush the back of the cutterhead. The flushing and seepage water generated from the strata can enter the mud chamber with the generated water flow. Under the action of the flushing system, the cutting face and back of the cutterhead can be flushed from multiple directions, providing multi-directional impact. This effectively flushes the excavated soil off the cutting face and various cutters, effectively preventing the formation of mud cakes on the cutting face and various cutters, and preventing the excavated soil from adhering to the cutters and affecting their continued excavation. This fully ensures the excavation effect and speed. The water pressure generated by the flushing can also maintain pressure on the cutting face, effectively preventing collapse due to insufficient pressure on the cutting face.

[0022] 2. In this type of shield tunneling machine with anti-mud cake on the cutterhead, the mud generated by the scouring enters the mud-water chamber through the slag openings on both sides of each main beam and secondary beam. Inside the mud-water chamber, it descends to the bottom under gravity. The mud gate can isolate or open the path between the mud-water chamber and the air cushion chamber. After the mud enters the air cushion chamber through the mud gate, it is stirred by the mud-water agitator to prevent the slag from accumulating inside the air cushion chamber behind the mud gate, ensuring smooth flow of mud through the air cushion chamber. After stirring, the mud passes through a grid to screen the slag particles entering the slurry discharge pipe, so that the particle size of the slag particles that can pass through the grid meets the power requirements of the slurry discharge pump, effectively preventing blockage of the slurry discharge pipe and ensuring smooth flow of mud inside the slurry discharge pipe.

[0023] 3. This type of tunnel boring machine with anti-mud cake on the cutterhead utilizes four evenly distributed flushing paths in the central panel flushing unit and four front flushing openings in the central opening flushing unit. Each front flushing opening has two mutually perpendicular flushing paths, ensuring that there are equally spaced flushing paths on the cutterhead's tunneling face, effectively flushing the cutterhead's tunneling face. On the back of the cutterhead, the vertical flushing openings are perpendicular to the back of the cutterhead, and the two transverse flushing pipes on the back each have two transverse flushing openings in opposite directions. The transverse flushing openings are all parallel to the back of the cutterhead, resulting in multiple flushing paths that are both perpendicular and parallel to the back of the cutterhead. This prevents the mud entering the slurry chamber from the various muck openings from forming cakes on the back of the cutterhead, ensuring the effectiveness of the flushing. Furthermore, since the flushing paths on the back of the cutterhead are smaller than those on the cutterhead face, it is easy to control the flushing pressure generated on the face to be greater than the pressure inside the slurry chamber. This pressure difference effectively prevents the formation of mud cakes on the face and various cutters, thus ensuring the excavation effect. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the cutting face of the cutterhead of the present invention;

[0025] Figure 2 This is a schematic diagram of the mud and water chamber, flushing system and air cushion chamber of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of the central back flushing unit and the central transverse flushing unit of the present invention;

[0027] Figure 4 This is a schematic diagram of the circulation process of the mud circulation system of the present invention;

[0028] Figure 5 This is a schematic diagram of the lower structure of the mud-water chamber and air-cushion chamber of the present invention;

[0029] Figure 6This is a schematic diagram of the structure of the mud gate of the present invention located on one side of the mud-water chamber;

[0030] Figure 7 This is a schematic diagram of the mud mixer and grid of the present invention;

[0031] Figure 8 This is a schematic diagram of the mud-water mixer of the present invention;

[0032] Figure 9 This is a schematic diagram showing the position of the advanced grouting system of the present invention on the surface of the central shield.

[0033] In the diagram: 1. Cutterhead; 11. Main beam; 12. Secondary beam; 13. Slag opening; 2. Slurry chamber; 3. Flushing system; 31. Center panel flushing unit; 32. Center opening flushing unit; 33. Center back flushing unit; 331. Back vertical flushing opening; 34. Center transverse flushing unit; 341. Back transverse flushing pipeline; 342. Back transverse flushing opening; 4. Air cushion chamber; 41. Slurry door; 41 1. Front gate; 412. Hydraulic rod; 413. Mud gate flushing nozzle; 42. Mud mixer; 421. Mixing impeller; 4221. Mixing fins; 422. Drive motor; 423. Wear-resistant outer cylinder; 43. Slurry discharge pipe; 44. Grille; 441. Grille flushing nozzle; 45. Air cushion chamber pressure holding system; 5. Mud circulation system; 6. Advanced grouting system; 61. Circumferential grouting hole; 62. Horizontal grouting hole. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] As described in the background section, there are shortcomings in the existing technology. In order to solve the above-mentioned technical problems, this application proposes a tunnel boring machine with a cutterhead anti-mud cake formation.

[0036] Please see Figures 1-9A tunnel boring machine (TBM) with a cutterhead for preventing mud cake formation includes a cutterhead 1. The excavation face of the cutterhead 1 is provided with several main beams 11 and several secondary beams 12. Each of the main beams 11 and secondary beams 12 has several cutting tools on its surface. The main beams 11 and secondary beams 12 are evenly spaced on the excavation face of the cutterhead 1. Each main beam 11 and secondary beam 12 has a muck opening 13 on both sides. A slurry chamber 2 is provided on the back of the cutterhead 1. During the excavation process of the cutterhead 1, the generated muck flows along the cutterhead... The radial flow of material 1 enters the slurry chamber 2 through various excavation openings 13; it also includes a flushing system 3, which comprises a central panel flushing unit 31, a central opening flushing unit 32, a central back flushing unit 33, and a central transverse flushing unit 34; the central panel flushing unit 31 and the central opening flushing unit 32 are used to flush the excavation face of the cutterhead 1, and the central back flushing unit 33 and the central transverse flushing unit 34 are used to flush the back of the cutterhead 1; the slurry chamber 2 is far from... An air cushion chamber 4 is located on one side away from the cutterhead 1. A mud gate 41 is provided between the mud-water chamber 2 and the air cushion chamber 4 to isolate the mud-water chamber 2 and the air cushion chamber 4. A mud-water agitator 42 is located at the bottom of the air cushion chamber 4. A slurry discharge pipe 43 is located at the bottom of the air cushion chamber 4 on the side away from the air cushion chamber 4. A grid 44 is provided at the end of the slurry discharge pipe 43 near the mud-water agitator 42. The mud-water agitator 42 is used to agitate the bottom of the air cushion chamber 4. The slurry discharge pipe 43 and the discharge pipe 44 are connected to the air cushion chamber 4. The slurry pumps are interconnected. The grid 44 is used to screen the particle size of the slag entering the slurry discharge pipe 43. The particle size of the slag through the grid 44 can meet the power requirements of the slurry discharge pump. It also includes a mud circulation system 5. The mud and water collected from the slurry discharge pipe 43 can be treated and supplied to the flushing system 3, the air cushion chamber pressure holding system 45 and the advanced grouting system 6. The air cushion chamber pressure holding system 45 is used to maintain the mud level inside the air cushion chamber 4, and the advanced grouting system 6 is used to reinforce the geology of the cutterhead 1 excavation face.

[0037] During use, the flushing system 3 pre-operates, maintaining a certain pressure at both the front and rear ends of the cutterhead 1 (the front end facing the direction of the tunneling face, and the rear end facing away from the tunneling face). This pressure ensures pressure during tunneling, preventing collapse of the front end of the cutterhead 1. It also provides lubrication to the cutters on the surface of the cutterhead 1, reducing the forward pressure on the cutters and minimizing heat accumulation during use, thus reducing frictional losses. Under the pushing and rotating force at the rear end of the cutterhead 1, the cutterhead 1 tunnels towards the designated tunneling face. Since the main beams 11 and secondary beams 12 are evenly spaced on the tunneling face of the cutterhead 1, each of the main beams 11 and secondary beams 12 has several cutters on its surface. Each main beam 11 and secondary beam 12 has muck openings 13 on both sides, allowing the muck generated by the cutters breaking the strata to flow radially along the cutterhead 1 during its rotation. The muck enters the slurry chamber 2 through the muck openings 13. During tunneling, the muck flows through the center... Both the face flushing unit 31 and the center opening flushing unit 32 are used to flush the cutting face of the cutterhead 1, while the center back flushing unit 33 and the center transverse flushing unit 34 are used to flush the back of the cutterhead 1. The flushing and seepage water generated from the strata can enter the slurry chamber 2 along with the generated water flow. Under the action of the flushing system 3, the cutting face and back of the cutterhead 1 can be flushed from multiple directions, providing impact in multiple directions (in actual use, the flushing pressure generated at the cutting face is greater than...). The pressure inside the mud chamber 2 is 3 bar, which has a good flushing effect and can produce a good anti-mud cake effect. It effectively flushes the excavated soil off the excavation face of the cutterhead 1 and each cutter, which can effectively prevent the formation of mud cakes on the excavation face of the cutterhead 1 and each cutter. It prevents the excavated soil (mud cake) from adhering to the cutter and affecting the continued excavation of the cutter. It can fully guarantee the excavation effect and excavation speed. It can also maintain the pressure of the excavation face through the water pressure generated by flushing, effectively preventing the collapse caused by insufficient pressure of the excavation face.

[0038] The slurry (including slag, stones, etc.) generated by the scouring enters the slurry chamber 2 through the slag openings 13 set on both sides of each main beam 11 and secondary beam 12. Inside the slurry chamber 2, it descends to the bottom of the slurry chamber 2 under the action of gravity. The slurry door 41 can isolate or open the path between the slurry chamber 2 and the air cushion chamber 4. After the slurry enters the air cushion chamber 4 through the slurry door 41, it is stirred under the action of the slurry agitator 42 to prevent the slag from accumulating inside the air cushion chamber 4 behind the slurry door 41, and to ensure that the slurry flows smoothly through the air cushion chamber 4. After stirring, the slurry passes through the grid 44 to screen the slag particles entering the discharge pipe 43 so that the slag particles passing through the grid 44 can meet the power requirements of the discharge pump, so as to effectively prevent the blockage of the discharge pipe 43 and ensure the smooth flow of slurry inside the discharge pipe 43.

[0039] In use, the mud circulation system 5 allows the mud water collected from the discharge pipe 43 to be treated and supplied to the flushing system 3, the air cushion chamber pressure holding system 45, and the advanced grouting system 6. The air cushion chamber pressure holding system 45 is used to maintain the mud level inside the air cushion chamber 4, and the advanced grouting system 6 is used to reinforce the geology of the cutterhead 1 tunneling face in order to maintain the slurry demand during the tunneling process, reduce water pollution, and improve water utilization efficiency.

[0040] Further, please refer to Figures 1-3 The central panel flushing unit 31 is located at the center of the tunneling face of the cutterhead 1, and the central panel flushing unit 31 has four evenly distributed flushing paths; the central opening flushing unit 32 is located outside the central panel flushing unit 31, and the central opening flushing unit 32 includes four front flushing openings, each of which has two mutually perpendicular flushing paths; the central panel flushing unit 31 and the central opening flushing unit 32 together have 12 flushing paths for flushing the tunneling face of the cutterhead 1, and the included angle between any two adjacent flushing paths is equal.

[0041] The central back flushing unit 33 includes two back vertical flushing openings 331, each of which is perpendicular to the back of the cutter head 1; the central transverse flushing unit 34 includes two back transverse flushing pipes 341, each of which has two back transverse flushing openings 342 in opposite directions, each of which is parallel to the back of the cutter head 1.

[0042] In use, the flushing system 3 is also equipped with a cutter flushing unit, which can independently flush the cutters set on the tunneling face of the cutterhead 1 to prevent mud from forming on the cutter surface and affecting the normal use of the cutters.

[0043] Therefore, during use, the four evenly distributed flushing paths set in the central panel flushing unit 31 and the four front flushing openings of the central opening flushing unit 32, each with two mutually perpendicular flushing paths, create 12 equally spaced flushing paths on the cutting face of the cutterhead 1, effectively flushing the cutting face of the cutterhead 1. On the back of the cutterhead 1, the back vertical flushing openings 331 are all perpendicular to the back of the cutterhead 1, and the two back transverse flushing pipes 341 each have two back transverse flushing openings 342 in opposite directions. The transverse flushing openings 342 are all parallel to the back of the cutterhead 1, thus creating multiple flushing paths perpendicular to and parallel to the back of the cutterhead 1. This prevents the mud entering the slurry chamber 2 from the various muck openings 13 from forming cakes on the back of the cutterhead 1, ensuring the effectiveness of flushing. Furthermore, since the flushing path on the back of the cutterhead 1 is smaller than the flushing path on the cutterhead 1's excavation face, it is easy to control the flushing pressure generated on the excavation face to be greater than the pressure inside the slurry chamber 2. This pressure difference can effectively prevent the formation of mud cakes on the excavation face and various cutters, thus effectively ensuring the excavation effect.

[0044] Further, please refer to Figures 1-2 , Figure 4 The mud circulation system 5 includes a discharge pump, a relay pump, an equalization tank, a sedimentation tank, a separation device, and a feed pump. The discharge pump is used to extract mud from the discharge pipe 43 and input the mud into the equalization tank, sedimentation tank, and separation device for processing through the relay pump. The processed slurry is supplied to the flushing system 3, the air cushion chamber pressure holding system 45, and the pre-grouting system 6 through the feed pump.

[0045] In use, the mud circulation system 5 allows the mud to be drawn from the discharge pipe 43 by the discharge pump, and then fed into the adjustment tank, sedimentation tank, and separation equipment by the relay pump for treatment (including pH adjustment, sedimentation, separation, etc., all of which are common technologies in the prior art and will not be described in detail here). The treated slurry is supplied to the flushing system 3, the air cushion chamber pressure holding system 45, and the pre-grouting system 6 by the slurry pump, which can effectively treat the mud generated during the tunneling and flushing processes. The treated slurry is used in combination with municipal water to maintain the slurry demand during the tunneling process, reduce water pollution, and improve water utilization efficiency.

[0046] In practical use, the mud circulation system 5 serves both to maintain the working face pressure and to remove slag. However, maintaining the working face pressure is the primary and essential function. To ensure construction safety, when the liquid level monitor shows that the liquid level in the air cushion chamber 4 has reached a low level, the discharge of mud from the air cushion chamber 4 must be stopped, and all relevant ball valves must be set to their respective positions.

[0047] Similarly, when the air cushion chamber 4 reaches a high liquid level, the slurry feeding into the air cushion chamber 4 and the mud and water chamber 2 will stop, and all relevant ball valves must be set to their respective positions.

[0048] The steps for adjusting the mud pressure in mud tank 2 are as follows:

[0049] Compare the previously calculated required mud volume with the measured mud injection volume. When the volume is close to the calculated required mud injection volume, briefly open the venting ball valve on the balance pipeline with a small opening to check whether the mud tank 2 is full. If mud leaks out, it means that the mud tank 2 is full and the mud injection ball valve can be closed. Otherwise, close the venting ball valve and continue to inject mud into the mud tank 2. Observe the mud pressure in the mud tank 2. If the pressure drops beyond the allowable value, open the mud injection ball valve to inject mud into the mud tank 2 until the mud pressure in the mud tank 2 reaches the set value. Close the air pressure holding system and reduce the pressure in the air cushion chamber 4 in a certain orderly manner.

[0050] The mud circulation system 5 has several working modes, including bypass mode, tunneling mode, reverse circulation mode, shutdown pressure holding mode, maintenance pressure holding mode, and pipeline extension mode.

[0051] 1) Bypass mode:

[0052] The bypass mode is an intermediate mode of the slurry circulation system. Before tunneling, the tunnel boring machine operator controls the pressure of the slurry inlet and outlet pipes by adjusting the speed of the slurry inlet pump and the slurry outlet pump until the optimal flow rate of slurry circulation is reached. At the same time, the slurry outlet pump / slurry inlet pump in the tunnel is synchronously adjusted to the required speed and flow rate.

[0053] 2) Tunneling mode:

[0054] Switching to tunneling mode is only possible via bypass mode. In tunneling mode, the speed of the feed / discharge pumps must be adjusted to achieve the required flow rate and pressure, which must be adapted to the advance speed and geological conditions. Tunneling mode requires at least three feed branches to be open ahead.

[0055] 3) Reverse loop mode:

[0056] When the bottom of mud and water chamber 2, the bottom of air cushion chamber 4, or the slurry discharge pipeline of the main unit section is blocked, the backwash mode is used to clear the blockage. This mode can achieve continuous flushing until the blockage is cleared.

[0057] 4) Shutdown and pressure holding mode:

[0058] When the tunnel boring machine is in a shutdown state for a long time, the mud in the mud chamber 2 may be lost. Therefore, it is necessary to control the mud level in the air cushion chamber 4 and replenish the mud when necessary.

[0059] 5) Maintenance pressure holding mode:

[0060] When the operator is repairing parts in the air cushion chamber 4, the mud door is closed, and the air cushion chamber 4 is no longer connected to the mud and water chamber 2. At this time, a pressure-holding air tank is used to ensure the stability of the pressure in the mud and water chamber 2, and at the same time, the mud in the mud and water chamber 2 can be replenished.

[0061] 6) Pipeline extension mode:

[0062] The pipeline extension mode needs to be switched when the machine is stopped. In order to extend the pipeline during the tunneling process, the slurry inlet / outlet pipeline needs to be lengthened periodically by the extension device. At the same time, the slurry in the slurry pipe needs to be treated. The system is designed with a slurry collection system to discharge the slurry in the main inlet / outlet pipeline to the air cushion chamber 4. The slurry is effectively recycled and reused, and zero leakage and zero pollution of slurry are achieved.

[0063] Further, please refer to Figures 1-2 , Figures 4-8 The mud gate 41 includes a front gate 411, with hydraulic rods 412 on both sides of the front gate 411. The hydraulic rods 412 are used to control the opening and closing of the front gate 411. Mud gate flushing nozzles 413 are also provided on both sides of the mud-water chamber 2 side of the mud gate 41. The mud gate flushing nozzles 413 are connected to the mud pump of the mud circulation system 5. The mud gate flushing nozzles 413 can flush the side of the front gate 411 located in the mud-water chamber 2 to prevent soil from accumulating in front of the side of the front gate 411 located in the mud-water chamber 2. In actual use, the opening size of the front gate 411 matches the maximum particle size that the stirring impeller 421 can crush. The front gate 411 is equipped with a safety pin to ensure safe inspection and maintenance work in the working chamber.

[0064] The mud mixer 42 includes a mixing impeller 421, a drive motor 422, and a wear-resistant outer cylinder 423. The wear-resistant outer cylinder 423 penetrates and is fixed inside the wall of the air cushion chamber 4. The mixing impeller 421 and the wear-resistant outer cylinder 423 are rotatably connected. The output shaft of the drive motor 422 penetrates inside the wear-resistant outer cylinder 423 and is fixed to the mixing impeller 421. The drive motor 422 can output power to drive the mixing impeller 421 to rotate and stir the bottom of the air cushion chamber 4, preventing the accumulation of slag behind the mud gate 41 and ensuring the smooth flow of the mud circulation system 5.

[0065] The stirring impeller 421 includes several stirring blades 4221. When the stirring blades 4221 rotate, they can break up the slag at the bottom of the air cushion chamber 4 to reduce the slag from clogging the grid 44. The grid 44 is located at the bottom of the side wall of the air cushion chamber 4 away from the mud chamber 2. On both sides of the side of the grid 44 located inside the air cushion chamber 4, there are grid flushing nozzles 441. The grid flushing nozzles 441 are connected to the slurry pump of the mud circulation system 5. The grid flushing nozzles 441 can flush the side of the grid 44 located inside the air cushion chamber 4 to prevent the slag from clogging the grid 44.

[0066] The air cushion chamber pressure-maintaining system 45 includes a liquid pressure-maintaining nozzle and a gas pressure-maintaining nozzle. The liquid pressure-maintaining nozzle is located in the middle of the air cushion chamber 4 and is connected to the slurry pump of the mud circulation system 5. The gas pressure-maintaining nozzle is connected to the pressure-maintaining air tank. The air cushion chamber pressure-maintaining system 45 can supply slurry to the inside of the air cushion chamber 4 through the liquid pressure-maintaining nozzle and supply compressed air to the inside of the air cushion chamber 4 through the gas pressure-maintaining nozzle to maintain the internal pressure of the air cushion chamber 4. Insufficient pressure and slurry inside the air cushion chamber 4 will affect the operation and maintenance of the tunnel boring machine.

[0067] During use, several stirring rods are installed on the partition between the mud and water chamber 2 and the air cushion chamber 4. The stirring rods can pre-stir the slag inside the mud and water chamber 2, making the slag entering the air cushion chamber 4 more loose and avoiding blockage of the air cushion chamber 4.

[0068] Further, please refer to Figures 1-2 , Figure 4 , Figure 9 The advanced grouting system 6 includes several circumferential grouting holes 61 and several horizontal grouting holes 62. The circumferential grouting holes 61 are evenly distributed around the shield shell of the shield machine, and the horizontal grouting holes 62 are set on the surface of the pressure baffle of the shield body of the shield machine. The several circumferential grouting holes 61 and several horizontal grouting holes 62 can be connected to a mud pump respectively, and the mud pump provides mixed mud to the several circumferential grouting holes 61 and several horizontal grouting holes 62 respectively.

[0069] The mud pump supplies mixed mud to several circumferential grouting holes 61 and several horizontal grouting holes 62. This is a common grout used for pressure curing in the prior art. The grouting volume and the preparation of the grout must be matched with the current tunneling strata.

[0070] Several circumferential grouting holes 61 and several horizontal grouting holes 62 can also be connected to the grouting pump of the mud circulation system 5. The grouting pump can provide treated grout to the several circumferential grouting holes 61 and several horizontal grouting holes 62 respectively, so as to reduce excessive extraction of municipal water. It can reduce water pollution and improve water utilization efficiency while maintaining the grout demand during the tunneling process.

[0071] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A tunnel boring machine with a cutterhead designed to prevent mud cake formation, characterized in that: Includes a cutterhead (1), the excavation face of the cutterhead (1) is provided with a number of main beams (11) and a number of secondary beams (12), and the surfaces of the main beams (11) and the secondary beams (12) are respectively provided with a number of cutting tools; The main beam (11) and the secondary beam (12) are evenly spaced on the excavation face of the cutterhead (1). Each main beam (11) and the secondary beam (12) has a slag opening (13) on both sides. A mud chamber (2) is provided on the back of the cutterhead (1). During the excavation process of the cutterhead (1), the generated slag flows radially along the cutterhead (1) and enters the mud chamber (2) from each of the slag openings (13). It also includes a flushing system (3), which includes a central panel flushing unit (31), a central opening flushing unit (32), a central back flushing unit (33), and a central transverse flushing unit (34); the central panel flushing unit (31) and the central opening flushing unit (32) are both used to flush the tunneling face of the cutterhead (1), and the central back flushing unit (33) and the central transverse flushing unit (34) are both used to flush the back of the cutterhead (1); An air cushion chamber (4) is provided on the side of the mud and water chamber (2) away from the cutter head (1). A mud door (41) is provided between the mud and water chamber (2) and the air cushion chamber (4). The mud door (41) is used to isolate the mud and water chamber (2) and the air cushion chamber (4). A mud-water agitator (42) is provided at the bottom of the air cushion chamber (4). A slurry discharge pipe (43) is provided at the bottom of the air cushion chamber (4) and on the side away from the air cushion chamber (4). A grid (44) is provided at the port of the slurry discharge pipe (43) near the mud-water agitator (42). The mud-water agitator (42) is used to agitate the bottom of the air cushion chamber (4). The slurry discharge pipe (43) is connected to the slurry discharge pump. The grid (44) is used to screen the particle size of the slag entering the slurry discharge pipe (43). The particle size of the slag through the grid (44) can meet the power requirements of the slurry discharge pump. It also includes a mud circulation system (5), from which mud and water collected from the discharge pipe (43) can be treated and supplied to the flushing system (3), the air cushion chamber pressure holding system (45) and the advanced grouting system (6). The air cushion chamber pressure holding system (45) is used to maintain the mud level inside the air cushion chamber (4), and the advanced grouting system (6) is used to reinforce the geology of the cutterhead (1) excavation face. The advanced grouting system (6) includes several circumferential grouting holes (61) and several horizontal grouting holes (62). The circumferential grouting holes (61) are evenly distributed around the shield shell of the shield machine, and the horizontal grouting holes (62) are set on the surface of the pressure baffle of the shield body of the shield machine. The plurality of circumferential grouting holes (61) and the plurality of horizontal grouting holes (62) can be connected to a mud pump respectively, and the mud pump provides mixed mud to the plurality of circumferential grouting holes (61) and the plurality of horizontal grouting holes (62) respectively; The plurality of the circumferential grouting holes (61) and the plurality of the horizontal grouting holes (62) can also be connected to the grout pump of the mud circulation system (5), and the grout pump can respectively supply the treated grout to the plurality of the circumferential grouting holes (61) and the plurality of the horizontal grouting holes (62).

2. A tunnel boring machine with a cutterhead anti-mud cake system according to claim 1, characterized in that: The central panel flushing unit (31) is located in the center of the excavation face of the cutterhead (1), and the central panel flushing unit (31) is provided with four evenly distributed flushing paths. The central opening flushing unit (32) is disposed on the outside of the central panel flushing unit (31). The central opening flushing unit (32) includes four front flushing openings, and each front flushing opening is provided with two flushing paths that are perpendicular to each other. The central panel flushing unit (31) and the central opening flushing unit (32) together have 12 flushing paths for flushing the tunneling face of the cutterhead (1), and the included angle between any two adjacent flushing paths is equal.

3. A tunnel boring machine with anti-mud cake formation on the cutterhead according to claim 1, characterized in that: The central back flushing unit (33) includes two back vertical flushing openings (331), each of which is perpendicular to the back of the cutter head (1). The central transverse flushing unit (34) includes two back transverse flushing pipes (341), each of which has two back transverse flushing openings (342) in opposite directions, and each of the back transverse flushing openings (342) is parallel to the back of the cutter head (1).

4. A tunnel boring machine with anti-mud cake formation on the cutterhead according to claim 1, characterized in that: The mud circulation system (5) includes a discharge pump, a relay pump, an adjustment tank, a sedimentation tank, a separation device, and a feed pump. The discharge pump is used to extract mud from the discharge pipe (43) and feed the mud into the adjustment tank, sedimentation tank, and separation device for processing through the relay pump. The processed slurry is then supplied to the flushing system (3), the air cushion chamber pressure holding system (45), and the advanced grouting system (6) through the feed pump.

5. A tunnel boring machine with a cutterhead anti-mud cake feature according to claim 4, characterized in that: The mud gate (41) includes a front gate (411), and hydraulic rods (412) are provided on both sides of the front gate (411). The hydraulic rods (412) are used to control the opening and closing of the front gate (411). Mud gate flushing nozzles (413) are also provided on both sides of the mud gate (41) located in the mud tank (2). The mud gate flushing nozzle (413) is connected to the mud circulation system (5) and the mud gate flushing nozzle (413) can flush the side of the front gate (411) located in the mud and water chamber (2).

6. A tunnel boring machine with anti-mud cake formation on the cutterhead according to claim 5, characterized in that: The mud mixer (42) includes a stirring impeller (421), a drive motor (422), and a wear-resistant outer cylinder (423). The wear-resistant outer cylinder (423) penetrates and is fixed inside the wall of the air cushion chamber (4). The stirring impeller (421) is rotatably connected to the wear-resistant outer cylinder (423). The output shaft of the drive motor (422) penetrates inside the wear-resistant outer cylinder (423) and is fixed to the stirring impeller (421). The drive motor (422) can output power to drive the stirring impeller (421) to rotate and stir the bottom of the air cushion chamber (4).

7. A tunnel boring machine with a cutterhead anti-mud cake feature according to claim 6, characterized in that: The stirring impeller (421) includes several stirring blades (4221), which can crush the slag at the bottom of the air cushion chamber (4) when rotating. The grille (44) is located at the bottom of the side wall of the air cushion chamber (4) away from the mud and water chamber (2). The grille (44) is also provided with grille flushing nozzles (441) on both sides of the side of the grille (44) inside the air cushion chamber (4). The grille flushing nozzles (441) are connected to the slurry pump of the mud circulation system (5). The grille flushing nozzles (441) can flush the side of the grille (44) inside the air cushion chamber (4).

8. A tunnel boring machine with a cutterhead anti-mud cake system according to claim 1, characterized in that: The air cushion chamber pressure holding system (45) includes a liquid pressure holding nozzle and a gas pressure holding nozzle. The liquid pressure holding nozzle is located in the middle of the air cushion chamber (4). The liquid pressure holding nozzle is connected to the slurry pump of the mud circulation system (5). The gas pressure holding nozzle is connected to the pressure holding gas tank. The air cushion chamber pressure-maintaining system (45) can supply slurry to the inside of the air cushion chamber (4) through the liquid pressure-maintaining nozzle and supply compressed air to the inside of the air cushion chamber (4) through the gas pressure-maintaining nozzle to maintain the internal pressure of the air cushion chamber (4).

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