A shield tunnel flue plate installation structure and construction method thereof

Abstract

The present invention provides a shield tunnel flue plate installation structure, comprising a flue plate and a steel bracket for supporting the flue plate. Along the transverse direction of the tunnel, a plurality of steel brackets are arranged on the inner walls of both sides of the pipe segment, and the steel brackets on each inner wall are arranged at intervals along the longitudinal direction of the tunnel. Both ends of the flue plate along the transverse direction of the tunnel are provided with flue plate embedded anchor bars, and both ends of the flue plate along the transverse direction of the tunnel are provided with flue plate embedded steel plates at the bottom, and anchor bolts for installing the steel brackets are provided on the pipe segment. Precast concrete blocks are filled between the ends of the flue plate along the transverse direction of the tunnel and the inner walls of the pipe segment, and the precast concrete blocks are pressed on the embedded steel plates of the flue plate. The longitudinal steel bars of the corbel pass through the steel brackets to connect the corbels into a whole along the longitudinal direction of the tunnel, the stirrups of the corbels are evenly arranged at a certain interval between the steel brackets, the embedded anchor bars of the flue plate extend into the range of the corbels, and the embedded anchor bars, the steel brackets, the longitudinal steel bars of the corbels and the stirrups of the corbels are cast with concrete together to form a cast-in-place corbel supporting the flue plate.

Description

Technical Field

[0001] The invention relates to the field of shield tunnel flue plate installation, and in particular to a shield tunnel flue plate installation structure and a construction method thereof. Background Art

[0002] Single-layer shield tunnels are generally divided into three layers: upper, middle and lower. The upper layer is the smoke exhaust channel 13, the middle layer is the driving area 14, and the bottom is the evacuation channel and cable pipeline corridor. In long-distance shield tunnels, the flue is an important smoke exhaust channel and a key link in disaster prevention. The shield tunnel flue is generally composed of cast-in-place brackets and prefabricated flue plates. The flue plate and bracket are constructed after the shield segment structure and the bottom box culvert are completed.

[0003] The existing flue plates are constructed by casting corbels by tying steel bars after planting reinforcement on a large scale on the pipe segments. After the corbels reach sufficient strength, the prefabricated flue plates are placed on the cast-in-place corbels by means of vertical lifting using lifting equipment and then rotating them to the installation position. Shrinkage compensating concrete is then filled on both sides of the corbels.

[0004] In the prior art, there are the following problems:

[0005] First, the existing installation method is to cast the corbel first and then hoist and install the flue plate. In order to meet the hoisting space and overlap requirements, the corbel size is large, which is not conducive to the use of tunnel clearance;

[0006] Second, due to the large distance between the contact point between the flue plate and the corbel and the pipe segment, and the large size of the corbel, a large number of rebars need to be planted on the pipe segment, posing a safety hazard;

[0007] Third, there is a lack of connecting parts between the flue plate and the corbel, which may fall off during a fire. Not only will the fire-proof function be lost, but the falling of the flue plate will pose a huge safety hazard to high-speed operating vehicles and will have a huge social impact. Summary of the invention

[0008] The purpose of the present invention is to overcome the defects of the prior art and provide a shield tunnel flue plate installation structure and a construction method thereof. The present invention at least solves some of the problems in the prior art.

[0009] The present invention is achieved in that:

[0010] The present invention provides a shield tunnel flue plate installation structure, comprising a flue plate and a steel bracket for supporting the flue plate. Along the transverse direction of the tunnel, a plurality of steel brackets are arranged on the inner walls of both sides of a pipe segment, and the steel brackets on each inner wall are arranged at intervals along the longitudinal direction of the tunnel. Both ends of the flue plate along the transverse direction of the tunnel are provided with flue plate embedded anchor bars, and both ends of the flue plate along the transverse direction of the tunnel are provided with flue plate embedded steel plates at the bottom, and anchor bolts for installing the steel brackets are provided on the pipe segment. Precast concrete blocks are filled between the ends of the flue plate along the transverse direction of the tunnel and the inner walls of the pipe segment, and the precast concrete blocks are pressed on the embedded steel plates of the flue plate. The longitudinal steel bars of the corbel pass through the steel bracket to connect the corbel into a whole along the longitudinal direction of the tunnel. Along the longitudinal direction of the tunnel, a plurality of corbel stirrups are arranged between the two steel brackets, and the corbel stirrups are arranged at intervals along the longitudinal direction of the tunnel. The embedded anchor bars of the flue plate extend into the range of the corbel, and the embedded anchor bars, the steel bracket, the longitudinal steel bars of the corbel and the corbel stirrups are cast with concrete together to form a cast-in-place corbel supporting the flue plate.

[0011] Furthermore, along the transverse direction of the tunnel, a number of corbel steel bars are provided on the inner walls on both sides of the pipe segment, and the corbel steel bars on each side of the inner wall are arranged at intervals along the longitudinal direction of the tunnel. A corbel steel bar is arranged between two steel supports, and the longitudinal corbel steel bars are tied with the corbel steel bars. The embedded anchor bars, steel supports, corbel steel bars, corbel longitudinal steel bars and corbel stirrups are cast together with concrete to form a cast-in-place corbel supporting the flue plate.

[0012] Furthermore, a raised support for supporting the embedded steel plate of the flue plate is provided on the top of the steel bracket.

[0013] Furthermore, a rubber pad is provided between the raised support and the embedded steel plate of the flue plate.

[0014] Furthermore, the steel support is welded by a plurality of angle steels, and a long strip hole for the anchor bolt to pass through is provided on the angle steel on the side of the steel support facing the pipe segment.

[0015] Furthermore, the prefabricated concrete block is trapezoidal.

[0016] The present invention also provides a construction method for a shield tunnel flue plate installation structure, comprising the following steps:

[0017] S1. Prefabricate the flue plate and embed anchor bars and steel plates in the flue plate;

[0018] S2. Anchor bolts and corbel reinforcements are installed on the segments;

[0019] S3. Lift the flue plate and install the prefabricated flue plate to the designed position;

[0020] S4, installation of steel supports: erect steel supports at certain intervals along the longitudinal direction of the tunnel, fix anchor bolts, and weld the anchor bolts and steel supports after fixation;

[0021] S5. A raised support is placed on the steel bracket, and the prefabricated flue plate is placed on the raised support. The flue plate and the inner wall of the pipe segment are filled with prefabricated concrete blocks, and the prefabricated concrete blocks press the embedded steel plate of the flue plate;

[0022] S6. Construction of steel support concrete corbels: tying the longitudinal reinforcement and stirrups of the corbels, setting up the formwork and pouring concrete to form reinforced concrete corbels;

[0023] S7. After the strength is reached, the formwork is removed, and the gaps between the flue plate and the corbel are sealed to complete the construction.

[0024] The present invention has the following beneficial effects:

[0025] 1. In the present invention, the flue plate is hoisted first and then the corbel is cast. The flue plate is lengthened and the corbel size is reduced, which optimizes the shield clearance and improves the utilization space of the shield tunnel section. The present invention solves the problem that in the existing installation, the corbel is cast in place first and then the flue plate is hoisted. In order to meet the hoisting space and overlap requirements, the corbel size is large, which is not conducive to the utilization of the tunnel clearance.

[0026] 2. Pre-embed steel plates and pre-embed anchor bars on the flue plate. The pre-embedded anchor bars of the flue plate are anchored to the cast-in-place corbels. The pre-embedded steel plates of the flue plate are pressed under the precast concrete blocks to strengthen the connection and fixation between the flue plate and the corbels. If the flue plate is damaged under fire conditions, the structure can be damaged without collapsing due to the snap action of the pre-embedded anchor bars and pads (precast concrete blocks) of the flue plate, thus preventing the shield top segment structure from being directly affected by the fire.

[0027] 3. The flue plate is supported by steel brackets, and only the steel brackets are connected to the segment structure through anchor bolts. Compared with the existing solution that requires embedding of reinforcement along the entire line, the post-anchor structure on the segment structure is greatly reduced, thereby reducing permanent damage to the shield segment structure and reducing structural risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 A schematic diagram of a prefabricated flue plate provided in an embodiment of the present invention;

[0030] Figure 2 A schematic diagram of a construction anchor bolt provided by an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of a suspended flue plate provided in an embodiment of the present invention;

[0032] Figure 4 A schematic diagram of installing a steel support and placing prefabricated concrete blocks provided in an embodiment of the present invention;

[0033] Figure 5 A schematic diagram of a steel support provided in an embodiment of the present invention;

[0034] Figure 6 A schematic diagram of the planar layout of the flue plate and the corbel structure provided in an embodiment of the present invention;

[0035] Figure 7 Schematic diagram of pouring reinforced concrete corbel provided by an embodiment of the present invention ( Figure 6 Middle AA section);

[0036] Figure 8 Schematic diagram of the non-steel frame area of ​​the corbel provided in an embodiment of the present invention ( Figure 6 mid-BB section);

[0037] Fig. 9 A construction flow chart provided for an embodiment of the present invention.

[0038] Markings in the figure: 1-anchor bolt; 2-steel bracket; 3-channel steel boss on the top of the steel bracket; 4-rubber pad; 5-precast concrete block; 6-flue plate; 7-embedded anchor bars of flue plate; 8-embedded steel plate of flue plate; 9-corbel longitudinal steel bars and corbel stirrups; 10-concrete corbel; 11-segment; 12-corbel steel bars; 13-smoke exhaust channel; 14-driving section; 15-reserved long strip holes in the steel bracket; 16-center line of the tunnel; 17-corbel edge line. DETAILED DESCRIPTION

[0039] The following will be combined with the 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 without creative work are within the scope of protection of the present invention.

[0040] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, the meaning of "several" is two or more.

[0041] like Figure 1-Figure 9 , Embodiment 1 of the present invention provides a shield tunnel flue plate installation structure, including a flue plate 6 and a steel bracket 2 for supporting the flue plate 6. In this embodiment, the flue plate 6 is a prefabricated flue plate, and the flue plate 6 has a plurality of pieces. Each of the flue plates 6 is sequentially spliced ​​along the longitudinal direction of the tunnel (the length direction of the tunnel). The flue plate 6 and the pipe segment at the top of the tunnel enclose a smoke exhaust channel 13. Along the transverse direction of the tunnel (the width direction of the tunnel), a plurality of steel brackets 2 are arranged on the inner walls of both sides of the pipe segment 11. The steel brackets 2 on each side of the inner wall are arranged at intervals along the longitudinal direction of the tunnel. Both ends of the flue plate 6 along the transverse direction of the tunnel are provided with flue plate pre-embedded anchor bars 7. Flue plate embedded steel plates 8 are provided at the bottom of both ends of the flue plate 6 along the transverse direction of the tunnel, and anchor bolts 1 for installing steel supports 2 are provided on the pipe segments 11. Precast concrete blocks 5 are filled between the ends of the flue plate 6 along the transverse direction of the tunnel and the inner walls of the pipe segments 11. The precast concrete blocks 5 are pressed on the flue plate embedded steel plates 8. The longitudinal steel bars of the corbel pass through the steel supports 2 to connect the corbels into a whole along the longitudinal direction of the tunnel. The stirrups of the corbels are evenly arranged at a certain interval between the steel supports. The embedded anchor bars 7 of the flue plate extend into the range of the corbels. The embedded anchor bars 7, the steel supports 2, the longitudinal steel bars of the corbels and the stirrups of the corbels are cast together with concrete to form a cast-in-place corbel supporting the flue plate 6.

[0042] Along the transverse direction of the tunnel, a number of corbel steel bars 12 are provided on the inner walls on both sides of the pipe segment 11. The corbel steel bars 12 on each side of the inner wall are arranged at intervals along the longitudinal direction of the tunnel. A corbel steel bar 12 is provided between the two steel supports 2. The longitudinal corbel steel bars are tied with the corbel steel bars 12. The embedded anchor bars 7, steel supports 2, corbel steel bars 12, corbel longitudinal steel bars and corbel stirrups are cast together with concrete to form a cast-in-place corbel supporting the flue plate 6.

[0043] A raised support is provided on the top of the steel bracket 2 to support the embedded steel plate 8 of the flue plate. In the present embodiment, the raised support is a channel steel boss 3 on the top of the steel bracket. A rubber pad 4 is provided between the channel steel boss 3 on the top of the steel bracket and the embedded steel plate 8 of the flue plate to further eliminate the elevation error of the support surface of each steel bracket 2 so that the flue plate load acts basically evenly on each steel bracket 2.

[0044] The steel support 2 is welded by a number of angle steels. A long strip hole for the anchor bolt 1 to pass through is opened on the angle steel of the steel support 2 facing the pipe segment 11. The exposed part of the anchor bolt 1 is provided with a thread. The anchor bolt 1 is fixed to the steel support 2 by a nut, and then the nut is welded to the steel support 2. The long strip hole makes it easy to eliminate the error of the anchoring position.

[0045] The precast concrete block 5 is trapezoidal in shape and is used as a template for cast-in-place corbels and also as a gap filler between the flue plate and the pipe segment.

[0046] The present invention achieves the effects of reducing the size of the corbel, strengthening the connection between the flue plate and the corbel, and reducing the implantation of reinforcing bars by adjusting the structural design of the flue plate and the corbel and the installation process. The main technical measures are as follows:

[0047] 1) Drill holes and plant the reinforcement (anchor bolt 1) at the designed position of the corbel anchor. The length of the planted reinforcement (anchor bolt 1) exposed outside the pipe segment 11 should meet the requirements for the later installation of the steel support 2, and the exposed part of the planted reinforcement (anchor bolt 1) should be threaded to facilitate the connection with the steel support 2 by bolts.

[0048] 2) Make the flue plate 6. The maximum length of the flue plate 6 should be determined by considering the shield construction error and the deformation of the segment structure. The end face of the flue plate is a downward inclined surface. A steel plate is embedded in the bottom of the end of the flue plate to facilitate the setting of the template for the later cast-in-place corbel. When making the flue plate 6, anchor bars should be embedded at the end to facilitate anchoring the flue plate 6 in the later cast corbel.

[0049] 3) Make the steel bracket 2. When making the steel bracket 2, a long strip bolt hole should be opened on the rod (angle steel) connected to the embedded reinforcement (anchor bolt 1) to eliminate the error of the embedded reinforcement position. A raised support (steel bracket top channel steel boss 3) is set at the contact part between the steel bracket and the flue plate 6 to support the flue plate 6 and serve as a positioning block for the concrete protective layer of the top rod of the steel bracket when the corbel concrete is cast in situ in the later stage.

[0050] 4) Make a filling concrete block (precast concrete block 5) between the flue plate 6 and the pipe segment 11. The precast concrete block 5 is trapezoidal and is used as a template when the corbel is cast in situ, and is also used to fill the gap between the flue plate and the pipe segment.

[0051] 5) Lift the flue plate 6 to a position slightly higher than the setting position.

[0052] 6) Install the steel bracket 2 and place a rubber pad 4 on the upper part of the channel steel boss 3 on the top of the steel bracket to further eliminate the elevation error of the support surface of each steel bracket 2 so that the flue plate load acts basically evenly on each steel bracket 2.

[0053] 7) Lower the flue plate 6 so that it sits on the steel support 2.

[0054] 8) Insert the prefabricated filling concrete blocks (prefabricated concrete blocks 5) from the gaps between the steel supports, and weld steel bars or steel plates through the embedded steel plates at the bottom of the flue plate ends to support the filling concrete blocks.

[0055] 9) Corbel reinforcement 12 is implanted in the pipe segment 11 in the non-steel frame area, and the corbel reinforcement 12 is used to bind the longitudinal reinforcement and stirrups at the corbel position.

[0056] 10) Install the formwork and pour the concrete at the corbel area.

[0057] 11) After the cast-in-place concrete of the corbel reaches the designed strength, the formwork is removed and the flue plate is sealed.

[0058] 12) Complete the construction.

[0059] The present invention utilizes designs such as steel brackets, concrete blocks (prefabricated concrete blocks 5), and pre-buried flue plates to improve the structural stability of the flue plates and improve the disaster prevention capability of the tunnel as a whole.

[0060] In the present invention, the flue plate is hoisted first and then the corbel is cast, the flue plate is lengthened and the corbel size is reduced, the shield clearance is optimized and the utilization space of the shield tunnel section is improved. The present invention solves the problem that in the existing installation, the corbel is cast in situ first and then the flue plate is hoisted, and in order to meet the hoisting space and overlap requirements, the corbel size is large, which is not conducive to the utilization of the tunnel clearance.

[0061] Steel plates and anchor bars are embedded in the flue plate, the embedded anchor bars 7 of the flue plate are anchored to the cast-in-place corbels, and the embedded steel plates 8 of the flue plate are pressed under the precast concrete blocks 5 to strengthen the connection and fixation between the flue plate and the corbels. If the flue plate is damaged under fire conditions, the structure can be damaged but not collapsed due to the snap action of the embedded anchor bars 7 of the flue plate and the cushion blocks (precast concrete blocks 5), thus preventing the shield top segment structure from being directly affected by the fire.

[0062] The flue plate is supported by the steel bracket 2, and only the steel bracket 2 is connected to the segment structure through the anchor bolt 1. Compared with the existing solution that requires embedding reinforcement along the entire line, the post-anchor structure on the segment structure is greatly reduced, thereby reducing permanent damage to the shield segment structure and reducing structural risks.

[0063] The present invention mainly includes flue plate bracket steel bracket, prefabricated concrete block (prefabricated concrete block 5), prefabricated flue plate, channel steel boss and other main components. The specific structure and construction method are as follows:

[0064] (1) The factory manufactures prefabricated flue plates, with pre-embedded steel bars for connecting the flue plates 6 with the corbels (pre-embedded anchor bars 7 for flue plates) and reserved steel plates at the ends (pre-embedded steel plates 8 for flue plates). After the flue plates are prefabricated, they are transported to the site for storage. After the anchor bolts 1 are installed at a certain interval on the pipe segments 11, they are hoisted to the prepared installation position. The hoisting height is slightly higher than the theoretical installation position, so as to complete the installation of the steel bracket 2;

[0065] (2) Factory prefabricated steel bracket 2, steel bracket 2 is welded from 6 angle steels, among which a long strip hole 10 is reserved on the angle steel near the pipe segment, and the width of the hole is slightly larger than the diameter of the anchor bolt. This provides error adjustment space for the installation of anchor bolt 1 to avoid the pipe segment steel bars. The prefabricated steel bracket 2 is transported to the site and hoisted to the designed elevation. The steel bracket 2 is fixed by tightening the anchor bolt nut, and the nut is fixed to the steel bracket by welding; the steel bracket is installed at a certain longitudinal spacing;

[0066] (3) After placing the channel steel boss and rubber gasket on the top of the steel frame, place the flue plate on the bracket channel steel boss, place a prefabricated concrete block 5 at the end of the flue plate, or weld a steel plate at the embedded steel plate at the end of the flue plate as the top template for pouring the concrete bracket of the steel bracket, and seal the gap after installation to complete the installation of the flue plate;

[0067] (4) Tie the corbel steel bars, implant the corbel steel bars 12 at a certain interval in the non-steel frame area, set up the formwork, complete the concrete pouring, and remove the formwork after reaching the design strength to complete the corbel construction

[0068] (5) Carry out structural sealing treatment such as flue plate corbels to complete the construction.

[0069] Embodiment 2 of the present invention provides a construction method for a shield tunnel flue plate installation structure, such as Fig. 9 , the structural construction sequence is:

[0070] The first step: prefabricate the flue plate 6, prefabricate the flue plate and embed anchor bars and steel plates in the flue plate;

[0071] Step 2: construct anchor bolts 1, plant reinforcement (plant corbel reinforcement 12), drill holes for anchor bolts 1 and corbel reinforcement 12 on the pipe segment 11;

[0072] Step 3: Lift the flue plate and hoist the prefabricated flue plate 6 to the designed position;

[0073] Step 4: Install the steel support. Set up the steel support 2 at a certain interval along the longitudinal direction of the tunnel, fix the anchor bolt 1, and weld the anchor bolt 1 and the steel support 2 after fixing. Place the channel steel boss, rubber gasket 4, and prefabricated concrete block 5 on the steel support 2. Place the prefabricated flue plate 6 on the channel steel boss. The prefabricated concrete block 5 presses the embedded steel plate 8 of the flue plate.

[0074] Step 5: Construction of steel support concrete corbels, tying the longitudinal reinforcement and stirrups of the corbels, setting up the formwork and pouring concrete to form reinforced concrete corbels;

[0075] Step 6: After the strength is reached, remove the formwork, caulk and seal the gaps between the flue plate and corbels to complete the construction.

[0076] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A shield tunnel flue plate installation structure, characterized in that: The invention comprises a flue plate and a steel bracket for supporting the flue plate. The flue plate is a prefabricated flue plate. The flue plate has several pieces. Each of the flue plates is spliced ​​in sequence along the longitudinal direction of the tunnel. The flue plate and the pipe segment at the top of the tunnel enclose a smoke exhaust channel. Along the transverse direction of the tunnel, several steel brackets are arranged on the inner walls on both sides of the pipe segment. The steel brackets on the inner walls on each side are arranged at intervals along the longitudinal direction of the tunnel. Both ends of the flue plate along the transverse direction of the tunnel are provided with flue plate embedded anchor bars. Both ends of the flue plate along the transverse direction of the tunnel are provided with flue plate embedded steel plates at the bottom. Anchor bolts for installing steel brackets are provided on the pipe segment. The end face of the flue plate is an inclined surface inclined downward. Prefabricated concrete blocks are filled between the end of the flue plate along the transverse direction of the tunnel and the inner wall of the pipe segment. The prefabricated concrete blocks are pressed on the embedded steel plates of the flue plate. The longitudinal reinforcement of the corbel passes through the steel bracket to connect the corbels along the longitudinal direction of the tunnel. As a whole, along the longitudinal direction of the tunnel, a number of corbel stirrups are arranged between the two steel supports, each of the corbel stirrups is arranged at intervals along the longitudinal direction of the tunnel, and the pre-embedded anchor bars of the flue plate extend into the corbel range; along the transverse direction of the tunnel, a number of corbel steel bars are arranged on the inner walls of both sides of the pipe segment, each of the corbel steel bars on the inner wall on each side is arranged at intervals along the longitudinal direction of the tunnel, a corbel steel bar is arranged between the two steel supports, the longitudinal steel bars of the corbel are tied with the corbel steel bars, and the pre-embedded anchor bars, steel supports, corbel steel bars, corbel longitudinal steel bars and corbel stirrups are cast together with concrete to form a cast-in-place corbel supporting the flue plate; a raised support supporting the embedded steel plate of the flue plate is provided on the top of the steel support, and the raised support is a channel steel boss on the top of the steel support; the precast concrete block is trapezoidal, and the precast concrete block is used as a template for casting the corbel, and is also used to fill the gap between the flue plate and the pipe segment.

2. The shield tunnel flue plate installation structure according to claim 1, characterized in that: A rubber pad is provided between the raised support and the embedded steel plate of the flue plate.

3. The shield tunnel flue plate installation structure according to claim 1, characterized in that: The steel bracket is welded by a plurality of angle steels, and a long strip hole for the anchor bolt to pass through is opened on the angle steel on the side of the steel bracket facing the pipe segment.

4. A construction method using the shield tunnel flue plate installation structure according to any one of claims 1 to 3, characterized in that: The steps include: S1. Prefabricate the flue plate and embed anchor bars and steel plates in the flue plate; S2. Anchor bolts and corbel reinforcements are installed on the segments; S3. Lift the flue plate and install the prefabricated flue plate to the designed position; S4, installation of steel supports: erect steel supports at certain intervals along the longitudinal direction of the tunnel, fix anchor bolts, and weld the anchor bolts and steel supports after fixation; S5. A raised support is placed on the steel bracket, and the prefabricated flue plate is placed on the raised support. The flue plate and the inner wall of the pipe segment are filled with prefabricated concrete blocks, and the prefabricated concrete blocks press the embedded steel plate of the flue plate; S6. Construction of steel support concrete corbels: tying the longitudinal reinforcement and stirrups of the corbels, setting up the formwork and pouring concrete to form reinforced concrete corbels; S7. After the strength is reached, the formwork is removed, and the gaps between the flue plate and the corbel are sealed to complete the construction.

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