Construction method of large-section shield tunnel starting system

Abstract

The application relates to a construction method of a large-section shield tunnel launching system, which comprises the following steps: pre-assembling the base of a shaped counterforce frame; pouring a hole portal steel ring in a concrete hole portal; pouring a launching base; butting and fixing the base with the remaining part of the shaped counterforce frame; sleeving a positioning steel ring in the launching shaft; and injecting cement slurry into the hole portal through a grouting pipe on the hole portal steel ring and a secondary grouting pipe on the hole portal sealing steel ring to seal the hole portal. The hole portal sealing steel ring is supported on the positioning steel ring, the positioning steel ring is additionally provided with locking bolts, the position of the hole portal sealing steel ring can be quickly adjusted and temporarily fixed, and the installation difficulty of the hole portal sealing steel ring is reduced; the rubber cord fabric is installed on the hole portal sealing steel ring in a flat manner, the rubber cord fabric can be prevented from being pulled, ellipsoidal, damaged and the like when being vertically placed, and the installation difficulty is reduced.

Description

Technical Field

[0001] This invention belongs to the field of tunnel construction, and in particular relates to a construction method for a large-section shield tunnel launching system. Background Technology

[0002] When constructing large-section shield tunnels, auxiliary facilities for the tunnel boring machine (TBM) need to be established within the launching shaft to ensure its smooth excavation and entry into the tunnel. During excavation, the TBM is primarily supported on a concrete foundation and then relies on a reaction frame to provide horizontal reaction force for forward excavation. Therefore, the construction quality of the concrete foundation and the stability of the reaction frame directly affect the overall tunnel construction quality. The concrete foundation is typically an arc-shaped structure with steel rails laid on top. Due to limited working space underground and the difficulty in forming the curved surface of cast-in-place concrete, it is often difficult to guarantee the construction accuracy of the curved surface during construction. Furthermore, the TBM's significant weight makes it susceptible to damaging the steel rails and causing displacement during the jacking process. The reaction frame is usually fabricated through on-site welding and then its bottom is cast into the concrete foundation. However, due to limited on-site working space, significant deviations in welding and installation accuracy can occur, easily affecting the TBM's jacking accuracy.

[0003] In addition, when the tunnel boring machine enters the tunnel, the gap between the tunnel entrance and the tunnel boring machine needs to be sealed. The conventional sealing measure is to install a rubber curtain around the outside of the tunnel entrance. However, because the rubber curtain is large in size, it is easy to bend, which can lead to poor sealing and grout leakage. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a construction method for a large-section shield tunnel launching system.

[0005] The construction method for this large-section shield tunnel launching system includes the following construction steps:

[0006] Step 1: Pre-assemble the base of the standardized reaction frame; weld the vertical supports, upper and lower crossbeams, stiffening rods and diagonal supports into a whole;

[0007] Step 2: Cast the steel ring for the tunnel entrance into the concrete tunnel entrance;

[0008] Step 3: Fix the base to the bottom plate of the working well; tie the base reinforcement bars, and then spot weld the standardized support ribs to the surface base reinforcement bars, and pour the starting base using the rigid side formwork and the flexible top formwork with pouring holes.

[0009] Step 4: Demold the formwork and install guide rails on the standardized support ribs; connect and fix the base to the remaining part of the standardized reaction frame;

[0010] Step 5: After installing the inner leaf spring, rubber curtain and outer pressure plate on the curtain installation ring of the tunnel portal sealing steel ring, connect them with the positioning steel ring in the starting working well. After aligning the tunnel portal sealing steel ring with the axis of the tunnel portal steel ring, tighten the locking bolts to fix it.

[0011] Step Six: Vertically support the tunnel boring machine on the guide rails and longitudinally support it on the standardized reaction frame. After the tunnel boring machine enters the tunnel, inject cement grout through the grouting pipe on the tunnel portal steel ring and the secondary grouting pipe on the tunnel portal sealing steel ring to seal the tunnel portal.

[0012] As a preferred option, in step one: the base is welded into a whole using connecting steel bars; arc-shaped stiffening blocks are welded between the vertical support, the upper beam, and the lower beam to form a whole; and the stiffening rod is welded to the two diagonal supports to form a whole.

[0013] As a preferred option, in step three: the standardized support ribs are processed according to the curvature and arc length of the starting base. The standardized support ribs have the same surface curvature as the starting base, and positioning grooves are opened on the convex surface of the standardized support ribs according to the spacing of the base reinforcement bars. Before welding, it is verified that the axis of the standardized support ribs is on the same straight line as the tunnel axis.

[0014] As a preferred option, step four is as follows: After the concrete of the launching base reaches the design strength, the flexible top formwork and rigid side formwork are removed, guide rails are installed on the standardized support ribs, and stiffening angle steels are welded on both sides of the guide rails; the entire structure formed by the vertical support, upper beam and lower beam in step one is hoisted into the launching working shaft, and the lower end of the vertical support is fitted onto the base through a connecting sleeve; the entire structure formed by the diagonal support and stiffening rod is hoisted into the launching working shaft, and the lower end of the diagonal support is fitted onto the base through a connecting sleeve; the spatial position of the standardized reaction frame is checked, and then the connecting sleeve is connected and fixed to the base and the diagonal support is connected and fixed to the vertical support using fastening bolts.

[0015] As a preferred option, step five specifically involves: laying the portal sealing steel ring horizontally on the ground, then installing the inner leaf spring, rubber curtain, and outer pressure plate onto the curtain mounting ring; then hoisting the portal sealing steel ring as a whole into the starting working shaft, avoiding bumping the portal sealing ring and damaging the rubber curtain during hoisting; placing the portal sealing steel ring onto the positioning steel ring, and tightening the locking bolts to align the axis of the portal sealing steel ring with the axis of the portal steel ring; the portal sealing steel ring is provided with a triangular stiffening plate on the outside, spot welding the triangular stiffening plate to the portal steel ring, and then fully welding the portal sealing steel ring to the portal steel ring.

[0016] As a preferred embodiment, in step five: the sealing steel ring of the tunnel entrance is provided with a curtain installation ring, the inner leaf spring, the rubber curtain and the outer pressure plate are fixed on the curtain installation ring, the inner leaf spring is fixed on the inner side of the curtain installation ring and abuts against the rubber curtain, the rubber curtain and the outer pressure plate are fixed on the outer side of the curtain installation ring, and the outer pressure plate is attached to the outer side of the rubber curtain.

[0017] The inner leaf spring is a flexible strip structure. The upper end of the inner leaf spring is fixed on the curtain mounting ring, and the lower end abuts against the rubber curtain. The contact area between the lower end of the inner leaf spring and the rubber curtain is a smooth surface.

[0018] The outer pressure plate is divided into a fixed section and a movable section. The fixed section is fixed on the curtain installation ring, and the movable section is attached to the rubber curtain. The fixed section and the movable section are connected by a pin. A torsion spring groove is provided at the hinge of the fixed section and the movable section. A torsion spring is provided in the torsion spring groove. The rubber curtain is vertically clamped between the inner leaf spring and the outer pressure plate.

[0019] Preferably, the diameter of the positioning steel ring is smaller than the diameter of the portal sealing steel ring; the positioning steel ring has locking bolts, and the positioning steel ring is fixedly connected to the portal sealing steel ring by the locking bolts.

[0020] Preferably, the portal steel ring is provided with a grouting pipe for injecting cement grout between the lining and the portal to seal it; the portal sealing steel ring is provided with two curtain installation rings, and a secondary grouting pipe is provided on the portal sealing steel ring, with the secondary grouting pipe located between the two curtain installation rings.

[0021] The large-section shield tunnel launching system is obtained by any of the methods described above.

[0022] The beneficial effects of this invention are:

[0023] 1) Casting standardized support ribs on the launching base not only provides stable and reliable support for the guide rails, but also serves as a support structure for the top template of the launching base, ensuring the forming accuracy of the launching base.

[0024] 2) The horizontal reaction frame of the tunnel boring machine adopts a standardized structure. After the standardized reaction frame is assembled into several independent units on the ground, it is then assembled into a whole in the working shaft by sleeves and bolts. The structure is simple, reliable, and has a strong load-bearing capacity.

[0025] 3) The portal sealing steel ring is supported on the positioning steel ring, which is also equipped with locking bolts. This allows for quick adjustment of the position of the portal sealing steel ring and temporary fixation, reducing the installation difficulty of the portal sealing steel ring.

[0026] 4) The rubber curtain is installed on the sealing steel ring of the opening by laying it flat, which can avoid the rubber curtain from being stretched, deformed and damaged when it is installed vertically, thus reducing the difficulty of installation.

[0027] 5) The rubber curtain is equipped with an inner leaf spring and an outer pressure plate on both sides to prevent the rubber curtain from tilting and to ensure that the tunnel boring machine can pass through the rubber curtain to enter the tunnel. Attached Figure Description

[0028] Figure 1This is a side view of the launching system for a large-section shield tunnel;

[0029] Figure 2 This is a top view of the launching system for a large-section shield tunnel;

[0030] Figure 3 Schematic diagram of the tunnel's starting portal structure;

[0031] Figure 4 This is a schematic diagram of the steel ring structure of the portal.

[0032] Figure 5 This is a schematic diagram of the portal sealing structure;

[0033] Figure 6 This is a half-section view of the three-dimensional structure of the steel ring of the tunnel entrance;

[0034] Figure 7 This is a half-section view of the three-dimensional structure of the sealing steel ring;

[0035] Figure 8 This is a side view of the outer pressure plate;

[0036] Figure 9 This is a schematic diagram of the three-dimensional structure of the outer pressure plate;

[0037] Figure 10 This is a schematic diagram showing the disassembly of the outer pressure plate structure;

[0038] Figure 11 This is a detailed drawing of the torsion spring installation. Figure 10 (Node A in the middle)

[0039] Figure 12 This is a three-dimensional structural diagram of the launching base and reaction frame;

[0040] Figure 13 This is a schematic diagram of the standardized three-dimensional support rib structure;

[0041] Figure 14 This is a schematic diagram of the placement of standardized support ribs;

[0042] Figure 15 This is a schematic diagram of the initial foundation formwork;

[0043] Figure 16 This is a schematic diagram showing the demolding of the starting base and the placement of the standardized support ribs;

[0044] Figure 17 This is a schematic diagram of a standardized reaction frame three-dimensional structure;

[0045] Figure 18 This is a schematic diagram of the vertical support and the splicing of the upper and lower horizontal beams;

[0046] Figure 19 This is a schematic diagram of the base structure;

[0047] Figure 20 This is a schematic diagram of a three-dimensional structure with oblique support;

[0048] Figure 21 This is a schematic diagram of the pre-embedded and positioned structure of the base;

[0049] Figure 22 This is a schematic diagram of the standardized reaction frame assembly and placement structure.

[0050] In the diagram, the markings are: 11-starting base, 12-guide rail, 13-stiffening angle steel, 21-standardized support rib, 22-positioning groove, 23-base reinforcement, 24-flexible top formwork, 25-rigid side formwork, 26-fixing bolt, 27-pouring hole, 3-standardized reaction frame, 31-base, 32-connecting reinforcement, 33-vertical support, 34-upper crossbeam, 35-lower crossbeam, 36-arc-shaped stiffening block, 37-diagonal support, 38-stiffening rod. 39-Connecting sleeve, 310-Fasting bolt, 41-Concrete portal, 42-Portal steel ring, 43-Grouting pipe, 44-Positioning steel ring, 45-Locking bolt, 51-Portal sealing steel ring, 52-Triangular stiffening plate, 53-Secondary grouting pipe, 54-Cloth installation ring, 55-Inner leaf spring, 56-Rubber cloth, 57-Outer pressure plate, 58-Fixed section, 59-Moving section, 510-Pin, 511-Torsion spring, 512-Torsion spring slot. Detailed Implementation

[0051] The present invention will be further described below with reference to embodiments. The description of the embodiments below is only for the purpose of helping to understand the present invention. It should be noted that those skilled in the art can make several modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0052] Example 1

[0053] As one example, the construction method of a large-section shield tunnel launching system includes the following construction steps:

[0054] Step 1: Based on the structural dimensions of the tunnel boring machine, manufacture the following components of the prefabrication plant: base 31, connecting steel bars 32, vertical support 33, upper crossbeam 34, lower crossbeam 35, arc-shaped stiffening block 36, inclined support 37, stiffening rod 38, and connecting sleeve 39 of the standardized reaction frame 3. After the components are manufactured, they are pre-assembled on the ground, and the base 31 is welded into a whole using the connecting steel bars 32; the arc-shaped stiffening block 36 is welded between the vertical support 33, upper crossbeam 34, and lower crossbeam 35 to form a whole, and the stiffening rod 38 is welded to the two inclined supports 37 to form a whole.

[0055] The standardized support rib 21 is processed according to the curvature and arc length of the starting base 11, and the positioning groove 22 is opened on the convex surface of the standardized support rib 21 according to the setting spacing of the base reinforcement 23.

[0056] Step 2: Manufacture the portal steel ring 42 according to the outer diameter of the tunnel boring machine, and pour the portal steel ring 42 into the concrete portal 41.

[0057] Step 3: Hoist the base 31 of the standardized reaction frame 3 into the starting working shaft as a whole, mark out the position of the base 31 and fix it to the bottom plate of the working shaft with anchor bolts; mark out the position of the starting base 11, tie the base reinforcement 23, and then spot weld the standardized support rib 21 to the surface base reinforcement 23. Before welding, check whether the axis of the standardized support rib 21 is on the same straight line as the tunnel axis; install the rigid side formwork 25 and the flexible top formwork 24 of the starting base 11, and pour the concrete of the starting base 11 from the pouring hole 27.

[0058] Step 4: After the concrete of the launching base 11 reaches the design strength, remove the flexible top formwork 24 and the rigid side formwork 25. Install the guide rail 12 on the standardized support rib 21 and weld stiffening angle steel 13 on both sides of the guide rail 12. Lift the vertical support 33, the upper crossbeam 34 and the lower crossbeam 35 into the launching working shaft as a whole. Fit the connecting sleeve 39 at the lower end of the vertical support 33 onto the base 31. Lift the inclined support 37 and the stiffening rod 38 into the launching working shaft as a whole. Fit the connecting sleeve 39 at the lower end of the inclined support 37 onto the base 31. Check the spatial position of the standardized reaction frame 3. Then use fastening bolts 310 to connect and fix the connecting sleeve 39 to the base 31 and the inclined support 37 to the vertical support 33.

[0059] Step 5: Lay the portal sealing steel ring 51 horizontally on the ground. Then, install the inner leaf spring 55, rubber curtain 56, and outer pressure plate 57 on the curtain installation ring 54. Laying the portal sealing steel ring 51 horizontally and installing the rubber curtain 56 can effectively avoid the rubber curtain 56 from being stretched, elliptical, or damaged when installed vertically, while also reducing the difficulty of operation for workers. Then, hoist the portal sealing steel ring 51 as a whole into the starting working shaft. During hoisting, avoid bumping the portal sealing steel ring 51 and damaging the rubber curtain 56. Put the portal sealing steel ring 51 on the positioning steel ring 44, and tighten the locking bolt 45 to adjust the axis of the portal sealing steel ring 51 to be aligned with the axis of the portal steel ring 42. Then, spot weld the triangular stiffening plate 52 to the portal steel ring 42 and fix it. Finally, fully weld the portal sealing steel ring 51 to the portal steel ring 42.

[0060] Step 6: The tunnel boring machine (TBM) is lowered into the starting shaft section by section. The TBM is vertically supported on the guide rail 12 and longitudinally supported on the standardized reaction frame 3. After the TBM enters the tunnel, cement grout is injected through the grouting pipe 43 and the secondary grouting pipe 53 to seal the tunnel entrance.

[0061] Example 2

[0062] As another embodiment, the large-section shield tunnel launching system obtained by the method in Embodiment 1, such as Figures 1 to 22 As shown, it includes a starting base 11, guide rails 12, standardized support ribs 21, standardized reaction frames 3, concrete portal 41, portal sealing steel ring 51, inner leaf springs 55, rubber curtains 56, and outer pressure plates 57, etc.

[0063] The curvature of the standardized support rib 21 is consistent with the curvature of the surface of the launching base 11. The standardized support rib 21 is cast inside the launching base 11, and the guide rail 12 is welded and fixed on the standardized support rib 21. The standardized support rib 21 has a positioning groove 22 at the bottom. During installation, the positioning groove 22 is stuck on the base reinforcement 23 and spot welded and fixed. When the launching base 11 is cast, a rigid side mold 25 is set on the side and a flexible top mold 24 is set on the top. The flexible top mold 24 is fixed on the standardized support rib 21 with fixing bolts 26. The standardized support rib 21 serves as the support for the flexible top mold 24, effectively ensuring the forming accuracy of the curved surface of the launching base 11. The flexible top mold 24 has a pouring hole 27 to facilitate the pouring of concrete for the launching base 11 from top to bottom.

[0064] The standardized reaction frame 3 includes a base 31, vertical supports 33, an upper crossbeam 34, a lower crossbeam 35, and diagonal supports 37, etc. These components are connected by welding or fastening bolts 310. The base 31 is integrally cast within the starting base 11. The bases 31 of the standardized reaction frame 3 are fixed together as a whole by connecting steel bars 32 to prevent displacement of the bases 31 during the casting of the starting base 11. The upper and lower ends of the two vertical supports 33 are respectively connected by the upper crossbeam 34 and the lower crossbeam 35. The crossbeam 35 is connected and fixed. The bottom of the vertical support 33 is provided with a connecting sleeve 39 inserted into the base 31. The upper end of the diagonal support 37 is supported on the vertical support 33. The lower ends of the vertical support 33 and the diagonal support 37 are provided with connecting sleeves 39 inserted into the base 31. The connection between the vertical support 33 and the upper crossbeam 34 and the lower crossbeam 35 is provided with an arc-shaped stiffening block 36. The diagonal supports 37 are provided with intersecting stiffening rods 38 to improve the stability of the entire fixed reaction frame 3.

[0065] The guide rail 12 is provided with stiffening angle steel 13 on both sides. The stiffening angle steel 13 is welded to the standardized support rib 21 and the stiffening angle steel 13 respectively. By setting the stiffening angle steel 13, the load-bearing capacity and stability of the guide rail 12 are improved, and it is prevented from detaching from the standardized support rib 21.

[0066] A portal steel ring 42 is cast on the concrete portal 41. A positioning steel ring 44 is provided on the portal steel ring 42. A portal sealing steel ring 51 is fitted onto the positioning steel ring 44 and fully welded to the portal steel ring 42 for fixation. The diameter of the positioning steel ring 44 is smaller than the diameter of the portal sealing steel ring 51, reducing the difficulty of fitting the portal sealing steel ring 51. A locking bolt 45 is provided on the positioning steel ring 44, allowing adjustment of the position of the portal sealing steel ring 51 and quick fixation of the portal sealing steel ring 51 by tightening the locking bolt 45. The portal steel ring 42 is also equipped with a grouting pipe 43 for injecting cement grout between the lining and the portal for sealing. After the tunnel boring machine enters the tunnel, cement grout is injected into the space between the lining and the portal through the grouting pipe 43 for sealing.

[0067] Multiple triangular stiffening plates 52 are provided on the outer side of the portal sealing steel ring 51. The triangular stiffening plates 52 are spot welded to the portal steel ring 42, which not only improves the connection strength between the portal sealing steel ring 51 and the portal steel ring 42, but also temporarily fixes the portal sealing steel ring 51 before the full welding operation of the portal sealing steel ring 51 and the portal steel ring 42 is carried out. The secondary grouting pipe 53 is located between the two curtain installation rings 54, which facilitates the injection of cement grout between the rubber curtains 56 for sealing operation in the later stage, thereby improving the sealing effect at the portal.

[0068] The inner leaf spring 55, rubber curtain 56, and outer pressure plate 57 are fixed to the curtain mounting ring 54 of the portal sealing steel ring 51. The inner leaf spring 55 is fixed to the inner side of the curtain mounting ring 54 and abuts against the rubber curtain 56. The rubber curtain 56 and the outer pressure plate 57 are fixed to the outer side of the curtain mounting ring 54, with the outer pressure plate 57 tightly against the outer side of the rubber curtain 56. The inner leaf spring 55 is a flexible strip structure, with its upper end fixed to the curtain mounting ring 54 and its lower end abutting against the rubber curtain 56 to prevent the curtain from tilting inward. The lower end in contact with the rubber curtain 56 is smooth. The surface is smooth to avoid scratching the rubber curtain 56; the outer pressure plate 57 is divided into a fixed section 58 and a movable section 59. The fixed section 58 is fixed on the curtain mounting ring 54, and the movable section 59 is close to the rubber curtain 56. The fixed section 58 and the movable section 59 are hinged together by a pin 510. The hinge of the two sections is provided with a torsion spring groove 512, which contains a torsion spring 511. By setting the torsion spring 511, the movable section 59 is kept in a vertical state, so that the rubber curtain 56 is clamped between the inner leaf spring 55 and the outer pressure plate 57 and kept in a vertical state, preventing the rubber curtain 56 from tilting.

[0069] A secondary grouting pipe 53 is installed on the sealing steel ring 51 of the tunnel entrance.

Claims

1. A construction method of a large cross-section shield tunnel launching system, characterized in that, The construction steps include: Step one, pre-assemble the base (31) of the shaped counterforce frame (3); weld the vertical support (33), upper cross beam (34) and lower cross beam (35), stiffener (38) and diagonal support (37) into a whole respectively; Step two, pour the hole portal steel ring (42) into the concrete hole portal (41); Step three, fix the base (31) on the working well bottom plate; bind the base reinforcement (23), then spot weld the shaped support rib (21) and the base reinforcement (23) on the surface to fix, the rigid side mold (25) and the flexible top mold (24) with pouring hole (27), pour the starting base (11); according to the curvature and arc length of the starting base (11), process the shaped support rib (21), the surface curvature of the shaped support rib (21) is consistent with that of the starting base (11), and according to the setting interval of the base reinforcement (23), set the positioning groove (22) on the convex surface of the shaped support rib (21), and check the axis of the shaped support rib (21) and the tunnel axis before welding; the shaped support rib (21) is poured into the starting base (11), and the guide rail (12) is welded and fixed on the shaped support rib (21); the bottom of the shaped support rib (21) is provided with a positioning groove (22), which is clamped on the base reinforcement (23) and spot welded and fixed during installation; the starting base (11) is poured with rigid side mold (25) on the side and flexible top mold (24) on the top, the flexible top mold (24) is fixed on the shaped support rib (21) by using fixed bolt (26), and the flexible top mold (24) is provided with pouring hole (27); Step four, remove the mold, install the guide rail (12) on the shaped support rib (21); butt joint and fix the base (31) and the remaining part of the shaped counterforce frame (3); Step five, after installing the inner side plate spring (55), rubber curtain cloth (56) and outer side pressing plate (57) on the curtain cloth mounting ring (54) of the hole portal sealing steel ring (51), the hole portal sealing steel ring (51) is sleeved with the positioning steel ring (44) in the starting working well, the hole portal sealing steel ring (51) is aligned with the axis of the hole portal steel ring (42), and then the locking bolt (45) is screwed to fix; the hole portal sealing steel ring (51) and the hole portal steel ring (42) are fully welded and fixed; the diameter of the positioning steel ring (44) is smaller than that of the hole portal sealing steel ring (51); the positioning steel ring (44) has locking bolt (45), and the positioning steel ring (44) is fixedly connected with the hole portal sealing steel ring (51) through the locking bolt (45); The hole portal sealing steel ring (51) is provided with the curtain cloth mounting ring (54), the inner side plate spring (55), the rubber curtain cloth (56) and the outer side pressing plate (57) are fixed on the curtain cloth mounting ring (54), the inner side plate spring (55) is fixed on the inner side of the curtain cloth mounting ring (54) and abuts against the rubber curtain cloth (56), the rubber curtain cloth (56) and the outer side pressing plate (57) are fixed on the outer side of the curtain cloth mounting ring (54), and the outer side pressing plate (57) abuts against the outer side of the rubber curtain cloth (56); The inner side plate spring (55) is a flexible strip structure, the upper end of the inner side plate spring (55) is fixed on the cord mounting ring (54), the lower end abuts against the rubber cord (56), and the lower end of the inner side plate spring (55) is a smooth surface in contact with the rubber cord (56); The outer side pressing plate (57) is divided into a fixed section (58) and a movable section (59), the fixed section (58) is fixed on the cord mounting ring (54), the movable section (59) is attached to the rubber cord (56), the fixed section (58) and the movable section (59) are hingedly connected through a pin shaft (510), a torsion spring slot (512) is arranged at the hinge connection position of the fixed section (58) and the movable section (59), and a torsion spring (511) is arranged in the torsion spring slot (512); and the rubber cord (56) is vertically clamped between the inner side plate spring (55) and the outer side pressing plate (57); the rubber cord (56) is installed on the hole door sealing steel ring (51) in a flat manner. Step six: vertically support the shield machine on the guide rail (12) and longitudinally support the shield machine on the shaped reaction frame (3), after the shield machine enters the hole, inject cement slurry into the hole door through the grouting pipe (43) on the hole door steel ring (42) and the secondary grouting pipe (53) on the hole door sealing steel ring (51) to seal the hole door.

2. The construction method of a large cross-section shield tunnel launching system according to claim 1, characterized in that, In step one: use the connecting steel bars (32) to weld the base (31) into a whole; weld the arc-shaped stiffening blocks (36) between the vertical supports (33), the upper cross beams (34) and the lower cross beams (35) to form a whole, and weld the stiffening rods (38) and the two inclined supports (37) into a whole.

3. The construction method of a large cross-section shield tunnel launching system according to claim 1, characterized in that, Step four is specifically: after the concrete of the starting base (11) reaches the design strength, remove the flexible top mold (24) and the rigid side mold (25), install the guide rail (12) on the shaped support rib (21), and weld the stiffening angle steels (13) on both sides of the guide rail (12); the whole formed by the vertical supports (33), the upper cross beams (34) and the lower cross beams (35) in step one is hoisted into the starting shaft, the lower end of the inclined support (37) is sleeved on the base (31) through the butt joint sleeve (39), the whole formed by the inclined support (37) and the stiffening rod (38) is hoisted into the starting shaft, the lower end of the inclined support (37) is sleeved on the base (31) through the butt joint sleeve (39), the spatial position of the shaped reaction frame (3) is reviewed, and then the butt joint sleeve (39) is connected and fixed with the base (31) and the inclined support (37) by using the fastening bolts (310).

4. The construction method of a large cross-section shield tunnel launching system according to claim 1, characterized in that, The fifth step is: horizontally laying the hole sealing steel ring (51) on the ground, then installing the inner side plate spring (55), rubber curtain cloth (56) and outer side pressing plate (57) on the curtain cloth installation ring (54); then hoisting the hole sealing steel ring (51) into the starting shaft, avoiding knocking the hole sealing steel ring (51) and damaging the rubber curtain cloth (56) during hoisting, sleeving the hole sealing steel ring (51) on the positioning steel ring (44), adjusting the axis of the hole sealing steel ring (51) to be aligned with the axis of the hole steel ring (42) by screwing the locking bolt (45), welding the triangular reinforcing plate (52) on the outer side of the hole sealing steel ring (51) to the hole steel ring (42), and then full welding the hole sealing steel ring (51) and the hole steel ring (42).

5. The construction method of a large cross-section shield tunnel launching system according to claim 1, wherein, The hole steel ring (42) is provided with a grouting pipe (43) for injecting cement slurry between the lining and the hole; the hole sealing steel ring (51) is provided with two curtain cloth installation rings (54), and the hole sealing steel ring (51) is provided with a secondary grouting pipe (53) between the two curtain cloth installation rings (54).

6. A large cross-section shield tunnel launching system characterized by, The method of any one of claims 1 to 5.

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