Large-diameter shield ventilation shaft system and construction method

Abstract

The invention provides a large-diameter shield ventilation shaft system and a construction method. According to the scheme, the construction method comprises the following steps that S1, surveying and setting out are conducted, and a steel-concrete prefabricated pedestal is installed; s2, guide rail assembly and concrete formwork construction; s3, cast-in-place concrete construction; s4, designing a guide table on the shield tunneling machine, and air-pushing the guide table to pass through the air shaft; s5, assembling the negative ring duct pieces; and S6, the shield tunneling machine is started, and the negative ring duct piece is reinforced. According to the construction method of the large-diameter shield air shaft passing system, the construction period is short, the construction cost is low, the construction technical problem that the large-diameter shield cannot horizontally move to pass through the air shaft section under the working condition that the curve radius is large is solved, the construction method has the multiple construction advantages of being high in stability, high in efficiency, high in benefit and the like during implementation, and the technical benefit is remarkable.

Description

Technical Field

[0001] The invention relates to the field of tunnel engineering, and in particular to a large-diameter shield tunnel ventilation shaft system and a construction method. Background Art

[0002] Against the background of increasing density of urban rail transit lines, the line shape of urban rail transit is becoming increasingly complex due to the restrictions of planning and existing buildings. In order to avoid the influence of buildings (structures) and ensure the ventilation requirements of long-section tunnels, the plane line shape of the intermediate air shaft set in the subway tunnel with a longer line is usually designed as a small radius curve, resulting in an angle in the direction of the shield entering and exiting the air shaft, which increases the construction difficulty of the shield passing through the air shaft.

[0003] The commonly used methods of passing through the station of the shield machine currently include empty pushing and jacking, shield dismantling and passing through the station, and whole machine translation passing through the station. Among them, the shield dismantling passing through the station method requires reconnecting the pipeline and debugging after completing the translation, which prolongs the construction period; the whole machine translation passing through the station requires the use of special station jacking equipment for shield translation, and steel pipe supports and tracks must be set up simultaneously in the working shaft, which is cumbersome and difficult to construct, and increases safety risks; in addition to the above schemes, the foam concrete in and out hole process can also achieve fast shield passing through the station, but it is expensive and the preparation work before passing through the station takes a long time. Therefore, empty pushing and jacking passing through the station is particularly prominent in terms of construction period and cost, but the empty pushing and jacking passing through the station is technically difficult, and the guide platform structure design and negative ring segment reinforcement treatment are particularly important.

[0004] There is already a Chinese utility model patent application No. 201720663590.5, which discloses a guide platform structure that facilitates the shield machine to pass through the middle wind shaft. The guide platform structure effectively enhances the stability of the entire structure and increases the load-bearing capacity of the structure by setting up a transverse steel plate, a left fixed body and a steel bar system; at the same time, a steel sheet structure is set to prevent the shield machine from sliding sideways and accidents, and an explosion-proof slurry nut is also set to prevent the concrete inside the guide platform from exploding due to the excessive mass of the shield machine. However, the entire guide platform structure of this patent only improves its own load-bearing performance and construction stability, and does not effectively improve the construction efficiency of the guide platform in the wind shaft and the guide rail installation process.

[0005] Furthermore, China's invention patent application No. 201911334729.1 discloses a shield machine wind shaft device and its construction method. Through a simple combination of support structure, anti-slip structure, connection structure, and embedded structure, the operation plan and operation process of the traditional shield machine wind shaft are optimized, the construction period of the shield machine wind shaft link is shortened, the problem of tunnel linearity is solved, the tunnel linearity adjustment is achieved, and the shield machine wind shaft device is guaranteed to have sufficient bearing capacity and anti-deviating ability. However, this patent mainly solves the linearity problem of the guide platform through embedded components and cast-in-place concrete technology, and does not optimize the reinforcement of the air push device and the negative ring segment.

[0006] In view of this, it is urgent to invent a large-diameter shield ventilation shaft system construction method with fast construction speed, high construction safety, and outstanding economic and technical benefits. The present invention proposes a large-diameter shield ventilation shaft system construction method through experimental research, construction materials and construction method comparison, and combines and adopts new components such as steel-concrete prefabricated pedestal, reaction support seat steel frame, roller hydraulic jack, arc support plate, arc water-stop steel plate, etc., and has been verified by multiple projects, which can provide certain technical references for tunnel engineering and has good economic and technical benefits. Summary of the invention

[0007] The object of the present invention is to provide a large-diameter shield tunnel system and construction method for solving the above-mentioned technical problems.

[0008] In order to solve the above technical problems, the present invention provides a construction method of a large-diameter shield tunneling system, comprising the following steps:

[0009] S1. Installation of steel-concrete prefabricated pedestal: Install the steel-concrete prefabricated pedestal so that the central axis of the steel-concrete prefabricated pedestal is consistent with the central axis of the wind shaft;

[0010] S2. Guide rail assembly and concrete formwork construction: install the guide rails on the side pre-buried steel supports and the center pre-buried steel supports, and install the concrete formwork on the upper part of the steel-concrete prefabricated pedestal;

[0011] S3, cast-in-place concrete construction: Cast the cast-in-place concrete area, vibrate it with an attached vibrator installed on the concrete formwork, demould it after completion, and polish and clean the guide rail part exposed to the cast-in-place concrete;

[0012] S4. The shield machine is pushed through the air shaft without any support: After the front body of the shield machine is separated from the steel ring of the tunnel gate, the shell of the shield machine is gradually connected to the steel plate and the roller assembly, and an electrically controlled reaction force support is installed at the tail of the shield. The reaction force support seat steel frame and the roller hydraulic pusher are installed on the guide rail at the same time. Then, a hydraulic push rod is set between the reaction force support seat steel frame and the electrically controlled reaction force support, so that the hydraulic push rod and the roller hydraulic pusher push alternately, and the shield machine is pushed through the air shaft without any support;

[0013] S5. Negative ring segment assembly: After the shield machine is pushed to the starting support, a reaction frame is set up in the air shaft, and the negative ring segment is assembled between the reaction frame and the shield jack. The inner wall of the negative ring segment is additionally provided with a steel reinforcement piece through the second connecting bolt;

[0014] S6. When the shield machine starts, the negative ring segments are reinforced: before the shield machine starts, an arc-shaped water-stop steel plate is pre-installed on the embedded steel ring of the receiving end retaining wall. After the shield machine starts, transverse arc-shaped support plates are symmetrically installed on both sides of the negative ring segments that have escaped from the shield tail. At the same time, the outer side of the negative ring segments is tightened by the steel wire rope of the prestressed tensioner.

[0015] The beneficial effects of the present invention are:

[0016] (1) The present invention has developed a steel-concrete prefabricated pedestal shield wind shaft station foundation structure. The steel-concrete prefabricated pedestal and its embedded steel support structure not only avoid the existing on-site large-volume concrete layered pouring process of the guide platform structure, but also improve the setting accuracy of the steel support. The whole can be customized according to the curvature of the central axis of the wind shaft, shortening the on-site construction period while effectively improving the quality of the shield wind shaft station foundation.

[0017] (2) The present invention provides an integrated electric-controlled hydraulic jacking technology for the reaction support seat. Through the electric-controlled reaction support seat in the shield tail, the reaction support seat steel frame on the guide rail and the roller hydraulic jacking device, high-efficiency alternating jacking in the wind shaft and dynamic adjustment of the shield posture are achieved, which is easy to install and highly intelligent.

[0018] (3) The present invention optimizes the synchronous reinforcement technology of the negative ring segment inside and outside. The internal part is reinforced with steel reinforcement parts, and the external part is reinforced with transverse arc support plates and prestressed steel wire ropes. A prestressed tensioner is simultaneously set in the starting bracket to realize the circumferential tightening of the negative ring segment by the steel wire rope, which greatly improves the overall stability and safety of the shield secondary starting. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a longitudinal section diagram of the shield machine of the present invention being pushed through the ventilation shaft;

[0020] Figure 2 It is a schematic diagram of the reaction force support seat type steel frame structure of the present invention;

[0021] Figure 3 This is a cross-sectional view of the shield machine of the present invention being pushed through the ventilation shaft;

[0022] Figure 4 This is a schematic diagram of the steel-concrete prefabricated pedestal structure of the present invention;

[0023] Figure 5 It is a schematic diagram of guide rail installation of the present invention;

[0024] Figure 6 It is a position relationship diagram of cast-in-place concrete and guide rails of the present invention;

[0025] Figure 7 Schematic diagram of the reinforcement of the negative ring segment of the present invention;

[0026] Figure 8 This is a cross-sectional view of the installation of the arc-shaped water-stopping steel plate of the present invention;

[0027] Fig. 9 This is a cross-sectional view of the installation of the arc-shaped water-stopping steel plate of the present invention;

[0028] Fig.10 It is a schematic diagram of the closed soil box structural system of the present invention.

[0029] In the figure: 1. Soil in the reinforcement area; 2. Retaining wall; 3. Embedded steel ring; 4. Shield machine; 5. First connecting bolt; 6. Hinge plate; 7. Rubber curtain plate; 8. Pipe segment; 9. Electric control limit device; 10. Reaction support seat steel frame; 11. Hydraulic jacking rod; 12. Steel-concrete prefabricated pedestal; 13. Roller hydraulic jacking device; 14. Electric control reaction support; 15. Roller assembly; 16. Guide rail; 17. Side embedded steel support; 18. Cast-in-place concrete; 1 9. Limiting wing plate; 20. Central embedded steel support; 21. Negative ring segment; 22. Arc support plate; 23. Second connecting bolt; 24. Steel reinforcement; 25. Adjustable hydraulic support seat; 26. Wire rope; 27. Starting support; 28. Prestressed tensioner; 29. ​​Upper arc-shaped water-stop steel plate; 30. Lower arc-shaped water-stop steel plate; 31. Plain soil backfill layer; 32. Temporary support; 33. Plastic improved soil backfill layer; 34. Gravel backfill layer; 35. Tunnel gate. DETAILED DESCRIPTION

[0030] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0031] Those skilled in the art should understand that, in the disclosure of the present invention, the orientation or position relationship indicated by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0032] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0033] like Figure 1-Figure 10 The present invention provides a large-diameter shield tunneling system and a construction method, comprising the following steps:

[0034] S1. Measurement and layout, installation of the steel-concrete prefabricated pedestal 12: Determine the axis point and the limit points on both sides of the steel-concrete prefabricated pedestal 12 through online measurement and layout. After verification, transport the steel-concrete prefabricated pedestal 12 in batches to the wind shaft for installation. After installation, the central axis of the steel-concrete prefabricated pedestal 12 is consistent with the central axis of the wind shaft.

[0035] In the steps, Figure 4 As shown, a central embedded steel support 20 is arranged along the central axis on the top surface of the steel-concrete prefabricated pedestal 12, and side embedded steel supports 17 are symmetrically arranged along both sides of the central embedded steel support 20. The first section of the steel-concrete prefabricated pedestal 12 abuts against the retaining wall 2, and the last section abuts against the starting bracket 27.

[0036] The retaining wall 2 is arranged on the side of the soil body 1 in the reinforcement area.

[0037] S2, guide rail 16 assembly, concrete formwork construction: install the guide rail 16 assembly on the side embedded steel support 17 and the center embedded steel support 20, verify the concrete formwork axis and elevation position, and then install the concrete formwork on the upper part of the steel-concrete prefabricated pedestal 12. The concrete formworks are all customized steel formworks.

[0038] In this step, if Figure 5 As shown, the guide rail 16 is welded perpendicularly to the top surfaces of the central embedded steel support 20 and the side embedded steel support 17 .

[0039] S3. Construction of cast-in-place concrete 18: After the concrete formwork is fully inspected and qualified, the cast-in-place concrete 18 area is poured at one time and vibrated by an attached vibrator installed on the concrete formwork. After curing, the formwork is removed and the guide rail 16 part exposed to the cast-in-place concrete 18 is polished and cleaned.

[0040] In this step, if Figure 6 As shown, the base of the guide rail 16 is completely embedded in the cast-in-place concrete 18.

[0041] If there is a water-rich pebble layer geological condition that does not meet the technical conditions for air-pushing, a crushed stone backfill layer 34 is used to replace the cast-in-place concrete 18 on the basis of the steel-concrete prefabricated pedestal 12, and after a temporary support 32 is arranged in the wind shaft in an annular direction, the plastic improved soil backfill layer 33 is continued to be constructed to the top of the shield crossing area, and finally the plain soil backfill layer 31 is constructed to the groundwater level elevation to form a closed soil box structure system, such as Fig.10 As shown, the shield machine 4 can advance normally through the ventilation shaft.

[0042] S4. A guide platform is designed on the shield machine 4 to push the machine through the air shaft: after the front body of the shield machine 4 escapes from the steel ring of the tunnel gate 35, the shell of the shield machine 4 is gradually welded with steel plates and roller assemblies 15, and an electrically controlled reaction force support 14 is installed at the tail of the shield. A reaction force support seat steel frame 10 and a roller hydraulic jacking device 13 are simultaneously installed on the guide rail 16. Subsequently, a hydraulic jacking rod 11 is set up between the reaction force support seat steel frame 10 and the electrically controlled reaction force support 14. The electrically controlled limit device 9 is used to realize the alternating jacking of the hydraulic jacking rod 11 and the roller hydraulic jacking device 13, and the shield posture is dynamically adjusted to complete the push of the shield machine 4 through the air shaft.

[0043] Alternating pushing process: the electric control limit device 9 of the reaction support seat type steel frame 10 is opened, the electric control limit device 9 of the roller hydraulic pusher 13 is closed, and the hydraulic push rod 11 pushes forward → the electric control limit device 9 of the reaction support seat type steel frame 10 is closed, the electric control limit device 9 of the roller hydraulic pusher 13 is opened, the hydraulic push rod 11 retracts, and the roller pushes forward → repeat the operation to push to the starting support 27.

[0044] In this step, if Figure 2 As shown, an electric-controlled limit device 9 is provided at the center of the reaction support seat steel frame 10 , and limit wing plates 19 are symmetrically provided on both sides, and the limit wing plates 19 are provided on both sides of the guide rail 16 .

[0045] like Figure 1 As shown, an electric-controlled limit device 9 is provided at the center of the roller hydraulic pusher 13, and the electric-controlled limit device 9 of the roller hydraulic pusher 13 and the central electric-controlled limit device 9 of the reaction force support seat steel frame 10 are both connected to the electric-controlled reaction force support 14 through a circuit.

[0046] S5. Assembling the negative ring segments 21: After the shield machine 4 is pushed onto the starting support 27 in vain, a reaction frame is set up in the air shaft, and the negative ring segments 21 are manually assembled between the reaction frame and the shield jack. A steel reinforcement piece 24 is added to the inner wall of the negative ring segment 21 through the second connecting bolts 23.

[0047] In this step, if Figure 7 As shown, a plurality of steel reinforcement pieces 24 are symmetrically arranged and arranged throughout the inner wall of the negative ring segment 21 , and the bottom of the steel reinforcement piece 24 is connected and fixed to each abutting negative ring segment 21 through a second connecting bolt 23 .

[0048] Among them, after a plurality of negative ring segments 21 are spliced ​​along the circumferential direction, the plurality of negative ring segments 21 are assembled to form a whole segment 8 .

[0049] S6, shield machine 4 starts, and negative ring segment 21 is reinforced: before the shield starts, arc-shaped water-stop steel plates are welded on the embedded steel ring 3 of the receiving end retaining wall 2. After the shield machine 4 starts, transverse arc-shaped support plates 22 are symmetrically installed on both sides of the negative ring segment 21 that has escaped from the shield tail, and at the same time, the steel wire rope 26 of the prestressed tensioner 28 is used to tighten the outer side of the negative ring segment 21.

[0050] In the steps, Figure 8 , Fig. 9 As shown, the arc-shaped water-stopping steel plate includes an upper arc-shaped water-stopping steel plate 29 and a lower arc-shaped water-stopping steel plate 30 which are symmetrically arranged, and the upper arc-shaped water-stopping steel plate 29 and the lower arc-shaped water-stopping steel plate 30 are welded and connected perpendicularly to the embedded steel ring 3 .

[0051] When the embedded steel ring 3 is arranged at the enclosure wall 2 , the hinge plate 6 is simultaneously connected to the outer side of the embedded steel ring 3 along the circumferential direction through the first connecting bolt 5 , and the rubber curtain plate 7 is connected to the hinge plate 6 .

[0052] like Figure 7 As shown, an adjustable hydraulic support seat 25 is arranged on the side of the transverse arc support plate 22, and the bottom of the adjustable hydraulic support seat 25 is abutted against the side retaining wall 2; at least two prestressed tensioners 28 are symmetrically arranged on both sides of the starting support 27, and the steel wire rope 26 is wrapped around the outer periphery of the negative ring segment 21 and the two ends are cross-connected in at least two prestressed tensioners 28.

[0053] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present invention.

Claims

1. A construction method for a large diameter shield tunneling system, characterized in that: The following steps are involved: S1. Installation of the steel-concrete prefabricated pedestal (12): installing the steel-concrete prefabricated pedestal (12) so that the central axis of the steel-concrete prefabricated pedestal (12) is consistent with the central axis of the wind shaft; S2, guide rail (16) assembly, concrete formwork construction: install the guide rail (16) on the side pre-buried steel support (17) and the central pre-buried steel support (20), and install the concrete formwork on the upper part of the steel-concrete prefabricated pedestal (12); S3, construction of cast-in-place concrete (18): pouring the cast-in-place concrete (18) area, vibrating it with an attached vibrator installed on the concrete formwork, demoulding it after completion, and grinding and cleaning the part of the guide rail (16) exposed to the cast-in-place concrete (18); S4, the shield machine (4) is pushed through the air shaft without any support: after the front body of the shield machine (4) is separated from the steel ring of the tunnel door (35), the shell of the shield machine (4) is gradually connected with the steel plate and the roller assembly (15), and an electrically controlled reaction force support (14) is installed at the shield tail, and a reaction force support seat steel frame (10) and a roller hydraulic pusher (13) are simultaneously installed on the guide rail (16), and then a hydraulic push rod (11) is set between the reaction force support seat steel frame (10) and the electrically controlled reaction force support (14), so that the hydraulic push rod (11) and the roller hydraulic pusher (13) push alternately, and the shield machine (4) is pushed through the air shaft without any support; S5, assembling the negative ring segment (21): after the shield machine (4) is pushed empty to the starting support (27), a reaction frame is set up in the air shaft, and the negative ring segment (21) is assembled between the reaction frame and the shield jack, and a steel reinforcement piece (24) is added to the inner wall of the negative ring segment (21) through a second connecting bolt (23); S6, the shield machine (4) starts, and the negative ring segment (21) is reinforced: before the shield machine starts, an arc-shaped water-stopping steel plate is pre-installed on the embedded steel ring (3) of the receiving end retaining wall (2). After the shield machine (4) starts, transverse arc-shaped support plates (22) are symmetrically installed on both sides of the negative ring segment (21) that has escaped from the shield tail, and at the same time, the steel wire rope (26) of the prestressed tensioner (28) is tightened on the outside of the negative ring segment (21).

2. The construction method of the large-diameter shield tunneling system according to claim 1 is characterized in that: In step S(1), a central embedded steel support (20) is arranged along the central axis of the top surface of the steel-concrete prefabricated pedestal (12), and side embedded steel supports (17) are symmetrically arranged along both sides of the central embedded steel support (20). The first section of the steel-concrete prefabricated pedestal (12) is abutted against the enclosure wall (2), and the last section is abutted against the starting support (27).

3. The construction method of the large-diameter shield tunneling system according to claim 1 is characterized in that: In step S(2), the guide rail (16) is connected perpendicularly to the top surfaces of the central embedded steel support (20) and the side embedded steel support (17).

4. The construction method of the large-diameter shield tunneling system according to claim 1 is characterized in that: In step S(3), the base of the guide rail (16) is completely embedded in the cast-in-place concrete (18).

5. The construction method of a large-diameter shield tunneling system according to claim 1 is characterized in that: In step S (3), if there is a geological condition of a water-rich pebble layer, a crushed stone backfill layer (34) is used on the steel-concrete prefabricated pedestal (12) to replace the cast-in-place concrete (18), and after a temporary support (32) is arranged in an annular direction in the air shaft, a plastic improved soil backfill layer (33) is continuously constructed to the top of the shield crossing area, and finally a plain soil backfill layer (31) is constructed to the groundwater level elevation.

6. The construction method of a large-diameter shield tunneling system according to claim 1, characterized in that: In step S(4), an electric control limit device (9) is arranged at the center of the reaction support seat steel frame (10), and limit wing plates (19) are symmetrically arranged on both sides, and the limit wing plates (19) are arranged on both sides of the guide rail (16).

7. The construction method of a large-diameter shield tunneling system according to claim 1, characterized in that: In step S(4), an electrically controlled limit device (9) is provided at the center of the roller hydraulic pusher (13), and the electrically controlled limit device (9) of the roller hydraulic pusher (13) and the central electrically controlled limit device (9) of the reaction force support seat steel frame (10) are both connected to the electrically controlled reaction force support seat (14) through a circuit.

8. The construction method of a large-diameter shield tunneling system according to claim 1, characterized in that: In step S(6), the arc-shaped water-stopping steel plate includes an upper arc-shaped water-stopping steel plate (29) and a lower arc-shaped water-stopping steel plate (30) which are symmetrically arranged, and the upper arc-shaped water-stopping steel plate (29) and the lower arc-shaped water-stopping steel plate (30) are both connected perpendicularly to the embedded steel ring (3).

9. The construction method of a large-diameter shield tunneling system according to claim 1, characterized in that: In step S (6), an adjustable hydraulic support seat (25) is arranged on the side of the transverse arc support plate (22), and the bottom of the adjustable hydraulic support seat (25) is in contact with the side retaining wall (2); at least two prestressed tensioners (28) are symmetrically arranged on both sides of the starting support (27), and the steel wire rope (26) is wrapped around the outer periphery of the negative ring segment (21) and then the two ends are cross-connected in at least two prestressed tensioners (28).

10. A large diameter shield tunneling system, characterized in that: It is obtained by the construction method of the large-diameter shield ventilation shaft system according to any one of claims 1-9.

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