Pipe reducing connection structure for tunneling machine flushing
By setting radial threaded screws and sealant on the half-section mechanical connection structure, the problem of unstable connection between the half-section and the pipe fitting under high pressure environment is solved, and the stability and safety of the shield machine cutterhead flushing are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA RAILWAY 14TH BUREAU GRP LARGE SHIELD ENG CO LTD
- Filing Date
- 2025-08-11
- Publication Date
- 2026-07-21
AI Technical Summary
The existing couplings and fittings are unstable in the high-pressure flushing operation of the tunnel boring machine cutterhead, which can easily lead to a sudden drop in flushing pressure and safety accidents.
Several screws are installed along the radial thread on the split joint, and grooves are provided on the large-diameter pipe and the reducing pipe to form a tight mechanical connection. Combined with sealant and semi-circular ring plate structure, the connection stability and sealing performance are enhanced.
This effectively prevents pipe fittings from detaching under the impact of high-pressure water flow, ensures stable flushing pressure, improves construction efficiency, reduces the risk of safety accidents, and extends the service life of the connection structure.
Smart Images
Figure CN224533765U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of diameter-reducing connection technology for tunnel boring machine flushing pipes, and in particular to a diameter-reducing connection structure for tunnel boring machine flushing pipes. Background Technology
[0002] In the field of tunnel boring machine (TBM) construction, the cleaning of the TBM cutterhead is crucial. As a common construction method for underground tunnel projects such as subways and high-speed railways, the cutterhead of a TBM easily accumulates a large amount of mud during excavation, forming a mud cake. This not only reduces excavation efficiency but also shortens the lifespan of the cutters. Therefore, high-pressure water washing of the cutterhead is a key step in ensuring the smooth progress of TBM construction and maintaining the good working condition of the cutters. An efficient and reliable pipeline connection structure is the foundation for achieving high-pressure cutterhead washing.
[0003] In existing shield tunneling pressurized environments, the non-welded pipe diameter changing connection structure utilizes a split joint to achieve pipe diameter changing and non-welded connection, bringing significant progress to shield tunneling construction. This structure eliminates the need for welding operations under pressure, effectively avoiding the safety hazards of traditional welding methods. Furthermore, its compact structure and simple operation can meet the pipe connection needs of different construction environments, improving construction efficiency and safety to a certain extent, and providing a new solution for pipe connections in shield tunneling construction.
[0004] However, the commonly used half-joint connection method still has significant drawbacks. The connection between the half-joint and the pipe fitting mainly relies on friction. During high-pressure flushing operations on the tunnel boring machine cutterhead, the continuous impact of high-pressure water flow exerts a significant force on the pipe fitting, making it extremely easy for the pipe fitting to detach from the half-joint. Once the pipe fitting detaches, it not only causes a sudden drop in flushing pressure, greatly reducing the effectiveness of cutterhead flushing, interrupting normal flushing operations, and reducing construction efficiency, but it may also lead to safety accidents such as high-pressure water jetting inside the pipeline. Therefore, it is urgent to optimize and improve the existing non-welded pipe diameter reducing connection device in the pressurized environment of tunnel boring machines to solve the problem of unstable connection between the half-joint and the pipe fitting under high-pressure conditions. Utility Model Content
[0005] To address the problem of unstable connection between pipe joints and fittings under high pressure, this utility model provides a pipe diameter reducing connection structure for tunnel boring machine flushing.
[0006] To solve the above problems, the technical solution adopted by this utility model is as follows:
[0007] A pipe diameter reducing connection structure for shield tunneling machine (TBM) flushing includes a large-diameter pipe fixedly mounted on the TBM, a reducing pipe connected to the large-diameter pipe via a split joint, and several screws fitted onto the split joint to mate with both the large-diameter pipe and the reducing pipe. These screws are radially threaded onto the split joint, and grooves are provided on both the large-diameter pipe and the reducing pipe to accommodate the screws. This pipe diameter reducing connection structure, by installing several screws radially threaded onto the split joint and fitting grooves on the large-diameter pipe and the reducing pipe, allows the screws to be screwed into the grooves, forming a tight mechanical connection between the split joint and the large-diameter pipe / reducing pipe. This significantly enhances connection stability, effectively preventing pipe fittings from detaching from the split joint under high-pressure water pressure, ensuring stable flushing pressure, improving cutterhead flushing effect, and guaranteeing construction efficiency. Simultaneously, it reduces the risk of safety accidents such as high-pressure water jetting caused by pipe fitting detachment, providing a reliable guarantee for the safe operation of TBM construction.
[0008] Preferably, the split joint has a boss that mates with the screw; sealant is applied between the screw and the boss. The boss provides a stable mounting support point for the screw, further strengthening the mechanical connection between the split joint and the large-diameter pipe or reducing pipe. This ensures the overall structure remains tightly connected even under high-pressure water flow, effectively preventing pipe loosening and detachment. The sealant between the screw and the boss fills the gaps, forming a reliable sealing layer. This not only prevents high-pressure water leakage from the connection point, ensuring stable flushing pressure and improving the cutterhead flushing effect, but also reduces the risk of screw corrosion and connection failure due to water leakage. This extends the service life of the pipe connection structure, lowers the probability of safety accidents, and significantly improves the safety and reliability of pipe connections during tunnel boring machine (TBM) construction.
[0009] Preferably, the split joint includes two mating semicircular ring plates; the two semicircular ring plates are connected by bolts; a sealing strip is provided at the inner edge of the semicircular ring plates; a boss is fixedly provided on the outer wall of the semicircular ring plates. The sealing strip provided at the inner edge of the semicircular ring plates, together with the sealant between the screws and the boss, forms a double sealing protection system, further enhancing the sealing performance of the connection, preventing high-pressure water leakage, ensuring stable flushing pressure of the cutter head, and improving the flushing operation effect.
[0010] Preferably, a clearance groove is provided at the edge of the semi-circular ring plate to accommodate the sealing strip; the sealing strip includes two semi-circular ring strips; and a horizontal strip is fixedly provided at the corners of both semi-circular ring strips. The clearance groove at the edge of the semi-circular ring plate provides installation and positioning space for the sealing strip, ensuring a tight fit between the sealing strip and the semi-circular ring plate, avoiding misalignment during installation, and effectively improving installation efficiency and sealing reliability; designing the sealing strip as two semi-circular ring strips is compatible with the semi-circular ring plate structure of the split joint, facilitating installation and disassembly. The horizontal strips fixed at the corners not only fill the gaps at the joints of the semi-circular ring strips, preventing high-pressure water leakage from the corners, but also enhance the overall structural strength and toughness of the sealing strip, making it less prone to deformation and detachment under the impact of high-pressure water flow.
[0011] Preferably, the inner diameter of the semicircular ring is smaller than the inner diameter of the semicircular ring plate. This design allows the sealing strip to tightly press against the outer wall of the large-diameter or reducing pipe after installation, forming an interference fit. This effectively eliminates the gap between the pipe and the coupling, further enhancing the sealing effect, preventing high-pressure water leakage from the connection, and ensuring stable pressure during shield machine cutterhead flushing. The additional friction generated by this interference fit, combined with mechanical connection structures such as screws and bosses, significantly improves the connection strength between the coupling and the pipe, reducing the risk of pipe fittings detaching under high-pressure water impact. Simultaneously, this design ensures more even stress distribution on the sealing strip, reducing localized wear, extending the sealing strip's service life, and lowering maintenance frequency and costs due to seal failure, providing a reliable guarantee for the safe and efficient advancement of shield tunneling.
[0012] Preferably, both the outer wall of the large-diameter pipe and the outer wall of the large-diameter end of the reducing pipe are fitted with a second relief groove for the semi-circular ring. This relief groove provides a precise embedding space for the semi-circular ring, allowing for quick positioning during installation and a tight, accurate fit with the pipe. This prevents misalignment during installation and effectively improves installation efficiency. Furthermore, the interlocking structure formed by the semi-circular ring embedded in the relief groove enhances the sealing effect, better preventing high-pressure water leakage and ensuring stable pressure during cutterhead flushing. In addition, this design increases the contact area between the semi-circular ring and the pipe, resulting in a more uniform distribution of friction from the interference fit. Combined with the screws, bosses, and other mechanical connection structures on the coupling, this significantly improves the connection strength between the pipe and the coupling, effectively reducing the risk of pipe fitting detachment under high-pressure water impact, extending the service life of the connection structure, reducing maintenance costs, and providing strong support for the safe and efficient operation of tunnel boring machines.
[0013] Preferably, both the outer wall of the large-diameter pipe and the outer wall of the large-diameter end of the reducing pipe are equipped with a third relief groove in conjunction with the horizontal bar; the third relief groove connects to the second relief groove. The third relief groove in conjunction with the second relief groove provides precise installation positioning space for the horizontal bar, allowing it to be firmly embedded and seamlessly connected to the semi-circular ring bar, preventing high-pressure water leakage from the corners of the sealing strip and further strengthening the sealing system. The connection between the second and third relief grooves creates a continuous sealing structure between the semi-circular ring bar and the horizontal bar after installation, enhancing the overall integrity and continuity of the seal, optimizing the stress distribution on the sealing strip, and reducing the risk of seal failure due to stress concentration. Simultaneously, this structure, combined with mechanical connecting components such as screws and bosses, further improves the stability of the connection between the coupling and the pipe, ensuring that the pipe connection structure remains tight and reliable under continuous high-pressure water impact.
[0014] Preferably, limit blocks are fixedly provided at both ends of the semicircular ring plate; the distance from the center line of the semicircular ring plate to the bottom surface of the limit block is less than the inner diameter of the semicircular ring plate; the outer wall of the large-diameter pipe and the outer wall of the large-diameter end of the variable-diameter pipe are provided with limit grooves in coordination with the limit blocks. The limiting blocks fixed at both ends of the semi-circular ring plate cooperate with the limiting grooves on the large-diameter and reducing pipes, providing guidance and positioning for the installation of the half-joint and the pipeline, effectively avoiding positional deviations during installation and significantly improving installation efficiency. The design that the distance from the center line of the semi-circular ring plate to the bottom surface of the limiting block is less than the inner diameter of the semi-circular ring plate allows the limiting block to penetrate deep into the limiting groove of the pipeline, forming a mechanical limit when the half-joint is connected to the pipeline. Combined with connecting structures such as screws and bosses, this further enhances the overall stability of the connection and significantly reduces the risk of loosening or detachment of pipe fittings under the impact of high-pressure water flow. At the same time, this limiting structure can effectively disperse the stress on the pipeline connection, prevent structural damage caused by uneven stress, extend the service life of the pipeline connection structure, and reduce maintenance costs. In addition, the cooperation between the limiting block and the limiting groove can also prevent circumferential displacement between the pipeline and the half-joint to a certain extent, ensuring the sealing of the connection and ensuring stable pressure during the shield machine cutterhead flushing operation, providing a reliable guarantee for the safe and efficient advancement of shield construction.
[0015] As can be seen from the above technical solution, the advantages of this utility model include: the pipe diameter reducing connection structure for shield machine flushing, by setting several screws radially threaded on the split joint and setting grooves on the large-diameter pipe and the reducing pipe, screws are screwed into the grooves, so that a tight mechanical connection is formed between the split joint and the large-diameter pipe and the reducing pipe, which greatly enhances the connection stability, effectively avoids the situation where the pipes are detached from the split joint under the impact of high-pressure water flow, ensures stable flushing pressure, improves the flushing effect of the cutterhead, and ensures construction efficiency; at the same time, it reduces the risk of safety accidents such as high-pressure water jet caused by pipe detachment, and provides a reliable guarantee for the safe conduct of shield construction. Attached Figure Description
[0016] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of the structure of this utility model;
[0018] Figure 2 This is a cross-sectional structural diagram of the present invention;
[0019] Figure 3 This is a schematic diagram of the structure of the large-diameter pipe of this utility model;
[0020] Figure 4 This is a schematic diagram of the structure of the variable diameter pipe of this utility model;
[0021] Figure 5 This is a schematic diagram of the structure of the semi-circular ring plate of this utility model. Figure 1 ;
[0022] Figure 6 This is a schematic diagram of the structure of the semi-circular ring plate of this utility model. Figure 2 ;
[0023] Figure 7 This is a schematic diagram of the sealing strip of this utility model.
[0024] Explanation of reference numerals in the attached drawings: 1-Large diameter pipe, 2-Hop joint, 3-Reducer, 4-Screw, 5-Groove, 6-Relief groove two, 7-Relief groove three, 8-Limiting groove, 9-Bolt;
[0025] 201-Boss, 202-Semicircular ring plate, 203-Sealing strip, 204-Leaning groove one, 205-Limiting block; 2031-Semicircular ring strip, 2032-Horizontal strip. Detailed Implementation
[0026] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.
[0027] like Figure 1-4As shown, a pipe diameter reducing connection structure for flushing a tunnel boring machine includes a large-diameter pipe 1 fixedly installed on the tunnel boring machine. The large-diameter pipe 1 is connected to a reducing pipe 3 through a split joint 2. Several screws 4 are respectively provided on the split joint 2 to cooperate with the large-diameter pipe 1 and the reducing pipe 3. The several screws 4 are radially threaded on the split joint 2. Grooves 5 are provided on the large-diameter pipe 1 and the reducing pipe 3 to cooperate with the screws 4.
[0028] This pipe diameter reducing connection structure for shield tunneling machine flushing uses a series of screws 4 threaded radially along the split section 2, and grooves 5 provided on the large-diameter pipe 1 and the reducing pipe 3. Screwing the screws 4 into the grooves 5 creates a tight mechanical connection between the split section 2 and the large-diameter pipe 1 and the reducing pipe 3, greatly enhancing connection stability. This effectively prevents pipe fittings from detaching from the split section 2 under high-pressure water impact, ensuring stable flushing pressure, improving cutterhead flushing effect, and guaranteeing construction efficiency. Simultaneously, it reduces the risk of safety accidents such as high-pressure water jetting caused by pipe fitting detachment, providing a reliable guarantee for the safe operation of shield tunneling.
[0029] like Figure 5-6 As shown, a boss 201 is provided on the half-section 2 to mate with the screw 4; sealant is applied between the screw 4 and the boss 201. The boss 201 provides a stable mounting support point for the screw 4, further strengthening the mechanical connection between the half-section 2 and the large-diameter pipe 1 and the reducing pipe 3, ensuring that the overall structure remains tightly connected even under the impact of high-pressure water flow, effectively preventing the pipe fittings from loosening and detaching. The sealant applied between the screw 4 and the boss 201 fills the gaps, forming a reliable sealing layer. This not only prevents high-pressure water from leaking from the connection point, ensuring stable flushing pressure and improving the flushing effect of the cutterhead, but also reduces the risk of screw 4 corrosion and connection failure due to water leakage, extending the service life of the pipe connection structure, reducing the probability of safety accidents, and significantly improving the safety and reliability of the pipe connection during shield tunneling.
[0030] In the above configuration, the split joint 2 includes two mating semicircular ring plates 202; the two semicircular ring plates 202 are connected by bolts 9; a sealing strip 203 is provided at the inner edge of the semicircular ring plate 202; a boss 201 is fixedly installed on the outer wall of the semicircular ring plate 202. Limiting blocks 205 are fixedly installed at both ends of the semicircular ring plate 202; the distance from the center line of the semicircular ring plate 202 to the bottom surface of the limiting block 205 is less than the inner diameter of the semicircular ring plate 202; the outer wall of the large-diameter pipe 1 and the outer wall of the large-diameter end of the reducing pipe 3 are both provided with limiting grooves 8 to fit the limiting blocks 205. The sealing strip 203 provided at the inner edge of the semicircular ring plate 202, together with the sealant between the screw 4 and the boss 201, forms a double sealing protection system, further enhancing the sealing performance of the connection, preventing high-pressure water leakage, ensuring stable flushing pressure of the cutter head, and improving the flushing operation effect. The limiting blocks 205 fixed at both ends of the semicircular ring plate 202 cooperate with the limiting grooves 8 on the large-diameter pipe 1 and the reducing pipe 3, providing guidance and positioning for the installation of the half-joint 2 and the pipeline, effectively avoiding positional deviations during installation and greatly improving installation efficiency. The design that the distance from the center line of the semicircular ring plate 202 to the bottom surface of the limiting block 205 is less than the inner diameter of the semicircular ring plate 202 allows the limiting block 205 to penetrate deep into the pipeline limiting groove 8, forming a mechanical limit when the half-joint 2 is connected to the pipeline. Combined with the connecting structures such as the screw 4 and the boss 201, this further enhances the overall connection. The robustness of the connection significantly reduces the risk of pipe fittings loosening or detaching under the impact of high-pressure water flow. Simultaneously, this limiting structure effectively disperses stress at the pipe connection points, preventing structural damage caused by uneven stress, extending the service life of the pipe connection structure, and reducing maintenance costs. Furthermore, the cooperation between the limiting block 205 and the limiting groove 8 can, to a certain extent, prevent circumferential displacement between the pipe and the split joint 2, ensuring the sealing of the connection points and guaranteeing stable pressure during the shield machine cutterhead flushing operation, thus providing a reliable guarantee for the safe and efficient advancement of shield construction.
[0031] like Figure 7 As shown, a relief groove 204 is provided at the edge of the semi-circular ring plate 202 to cooperate with the sealing strip 203; the sealing strip 203 includes two semi-circular ring strips 2031; a horizontal strip 2032 is fixedly provided at the corner of each of the two semi-circular ring strips 2031. The clearance groove 204 provided at the edge of the semi-circular ring plate 202 provides installation and positioning space for the sealing strip 203, ensuring that the sealing strip 203 fits tightly with the semi-circular ring plate 202, avoiding misalignment during installation, and effectively improving installation efficiency and sealing reliability. The sealing strip 203 is designed as two semi-circular rings 2031, which are compatible with the structure of the semi-circular ring plate 202 of the half-joint 2, making it easy to install and disassemble. At the same time, the horizontal strips 2032 are fixed at the corners, which not only fill the gaps at the joints of the semi-circular rings 2031 to prevent high-pressure water from leaking from the corners, but also enhance the overall structural strength and toughness of the sealing strip 203, making the sealing strip 203 less prone to deformation and detachment under the impact of high-pressure water.
[0032] The inner diameter of the semicircular ring 2031 is smaller than the inner diameter of the semicircular ring plate 202. Both the outer wall of the large-diameter pipe 1 and the outer wall of the large-diameter end of the reducing pipe 3 are fitted with a relief groove 2 6 to accommodate the semicircular ring 2031. Both the outer wall of the large-diameter pipe 1 and the outer wall of the large-diameter end of the reducing pipe 3 are fitted with a relief groove 3 7 to accommodate the horizontal bar 2032; relief groove 3 7 connects to relief groove 2 6. The design of the inner diameter of the semicircular ring 2031 being smaller than that of the semicircular ring plate 202 allows the sealing strip 203 to tightly press against the outer wall of the large-diameter pipe 1 or the reducing pipe 3 after installation, forming an interference fit. This effectively eliminates the gap between the pipe and the half-joint 2, further enhancing the sealing effect, preventing high-pressure water from leaking from the connection, and ensuring stable pressure during the shield machine cutterhead flushing operation. The additional friction generated by this interference fit, combined with the mechanical connection structures such as the screw 4 and the boss 201, significantly improves the connection strength between the half-joint 2 and the pipe, reducing the risk of the pipe fittings detaching under the impact of high-pressure water. At the same time, this design makes the sealing strip 203 more evenly stressed, reducing local wear, extending the service life of the sealing strip 203, and reducing the maintenance frequency and cost caused by sealing failure, providing a reliable guarantee for the safe and efficient advancement of shield construction. The outer wall of the large-diameter pipe 1 and the outer wall of the large-diameter end of the reducing pipe 3, in conjunction with the relief groove 6 set in the semi-circular ring 2031, provides a precise embedding space for the semi-circular ring 2031. This allows the semi-circular ring 2031 to be quickly positioned during installation, achieving a tight and accurate fit with the pipe, avoiding misalignment during installation and effectively improving installation efficiency. Simultaneously, after the semi-circular ring 2031 is embedded in the relief groove 6, the two form a concave-convex fit structure, further enhancing the sealing effect and better preventing high-pressure water leakage, ensuring stable pressure during cutterhead flushing operations. Furthermore, this structural design increases the contact area between the semi-circular ring 2031 and the pipe, resulting in a more uniform distribution of frictional force generated by the interference fit. Combined with the screws 4 and bosses 201 on the half-joint 2, this significantly improves the connection strength between the pipe and the half-joint 2, effectively reducing the risk of pipe fittings detaching under high-pressure water impact, extending the service life of the connection structure, reducing maintenance costs, and providing strong support for the safe and efficient operation of tunnel boring machine (TBM) construction.The outer wall of the large-diameter pipe 1 and the outer wall of the large-diameter end of the reducing pipe 3 are fitted with the relief groove 3 7 set in the crossbar 2032 and connected to the relief groove 2 6, providing a precise installation positioning space for the crossbar 2032. This allows the crossbar 2032 to be firmly embedded and seamlessly connected with the semi-circular ring 2031, preventing high-pressure water from leaking from the corners of the sealing strip 203 and further strengthening the sealing system. Through the connection design of relief groove 2 6 and 3, the semi-circular ring 2031 and the crossbar 2032 form a continuous sealing structure after installation. This not only enhances the integrity and continuity of the seal but also optimizes the stress distribution of the sealing strip 203, reducing the risk of seal failure due to stress concentration. At the same time, this structure, together with mechanical connection components such as screw 4 and boss 201, further improves the stability of the connection between the split joint 2 and the pipeline, ensuring that the pipeline connection structure remains tight and reliable under the continuous impact of high-pressure water.
[0033] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A pipe diameter reducing connection structure for flushing a tunnel boring machine, comprising a large-diameter pipe (1) fixedly mounted on the tunnel boring machine, wherein the large-diameter pipe (1) is connected to a reducing pipe (3) via a coupling (2), characterized in that, Several screws (4) are provided on the half joint (2) to match the large diameter pipe (1) and the reducing pipe (3); the screws (4) are provided on the half joint (2) with radial threads; the large diameter pipe (1) and the reducing pipe (3) are provided with grooves (5) to match the screws (4).
2. The variable diameter connection structure for the flushing pipe of the tunnel boring machine according to claim 1, characterized in that, The joint (2) is fitted with a boss (201) on the screw (4); a sealant is provided between the screw (4) and the boss (201).
3. The variable diameter connection structure for the flushing pipe of the tunnel boring machine according to claim 1, characterized in that, The half-joint (2) includes two semi-circular ring plates (202) that are fitted together; the two semi-circular ring plates (202) are connected by bolts (9); a sealing strip (203) is provided on the inner edge of the semi-circular ring plate (202); and a boss (201) is fixedly provided on the outer wall of the semi-circular ring plate (202).
4. The variable diameter connection structure for the flushing pipe of the tunnel boring machine according to claim 3, characterized in that, The edge of the semi-circular ring plate (202) is provided with a relief groove (204) in conjunction with the sealing strip (203); the sealing strip (203) includes two semi-circular ring strips (2031); a horizontal strip (2032) is fixedly provided at the corner of each of the two semi-circular ring strips (2031).
5. The variable diameter connection structure for the tunnel boring machine flushing pipe according to claim 4, characterized in that, The inner diameter of the semicircular ring (2031) is smaller than the inner diameter of the semicircular ring plate (202).
6. The variable diameter connection structure for the flushing pipe of the tunnel boring machine according to claim 5, characterized in that, Both the outer wall of the large-diameter pipe (1) and the outer wall of the large-diameter end of the reducing pipe (3) are fitted with a relief groove (6) by a semi-circular ring (2031).
7. The variable diameter connection structure for the flushing pipe of the tunnel boring machine according to claim 6, characterized in that, Both the outer wall of the large-diameter pipe (1) and the outer wall of the large-diameter end of the reducing pipe (3) are equipped with a relief groove three (7) in conjunction with the crossbar (2032); the relief groove three (7) is connected to the relief groove two (6).
8. The variable diameter connection structure for the flushing pipe of the tunnel boring machine according to claim 3, characterized in that, Limiting blocks (205) are fixedly installed at both ends of the semi-circular ring plate (202); the distance from the center line of the semi-circular ring plate (202) to the bottom surface of the limiting block (205) is less than the inner diameter of the semi-circular ring plate (202); the outer wall of the large-diameter pipe (1) and the outer wall of the large-diameter end of the reducing pipe (3) are provided with limiting grooves (8) in conjunction with the limiting blocks (205).