A bolt-connected precast flue slab structure for shield tunnels and its construction method

Abstract

The present invention provides a bolt-connected prefabricated flue duct plate structure for shield tunnels, which includes flue duct plates and cast-in-place corbels. Along the longitudinal direction of the tunnel, the flue duct plates include a middle flat plate and flue duct plate crossbeams symmetrically and fixedly arranged at both ends of the middle flat plate. A sealing gasket is arranged between adjacent flue duct plates and they are connected by bolts. Along the longitudinal direction of the tunnel, continuous cast-in-place corbels are provided on the inner walls on both sides of the segment. Each cast-in-place corbel on each inner wall is continuously arranged along the longitudinal direction of the tunnel. Each flue duct plate is lapped on the supports of the cast-in-place corbels on both sides of the segment. Embedded chutes for the flue duct plates are provided on the supports of the cast-in-place corbels on both sides along the transverse direction of the tunnel. The cast-in-place corbels are connected to the flue duct plates by bolts, and the connection between the cast-in-place corbels and the flue duct plates is filled with a sealing material. The gap between the end of the flue duct plate along the transverse direction of the tunnel and the inner wall of the segment is filled with a sealing material. The present invention solves the problems of reducing the thickness and weight of the flue duct plates under the condition of limited internal space in the shield, reducing the hoisting difficulty, and being able to cope with the positioning influence caused by the curve of the tunnel and the assembly error.

Description

Technical Field

[0001] The present invention relates to the field of shield tunnel flue board construction, and more particularly to a bolt-connected prefabricated shield tunnel flue board structure and construction method. Background Art

[0002] At present, the length of large-diameter shields is getting longer and longer. To ensure effective smoke exhaust under fire conditions, a flue is often set up for longitudinal smoke exhaust. Therefore, a large-diameter single-layer highway shield tunnel is generally divided into three layers: the upper layer is the smoke exhaust channel, the middle layer is the driving channel, and the lower layer is the evacuation and pipeline layout space.

[0003] The smoke exhaust channel is used for centralized smoke exhaust when a fire occurs in the tunnel. The cross-sectional area of the channel is affected by factors such as the tunnel length and use, and needs to meet the requirements of relevant specifications. The smoke exhaust channel is usually separated by the top segment and the flue board at the bottom of the smoke exhaust channel. The flue board is placed on the corbel, and the corbel is connected to the shield tunnel segment. The main load of the flue board is its own weight. The flue board needs to meet the requirements of bearing capacity and deformation. To ensure the longitudinal smoke exhaust effect of the tunnel, the flue needs to have good sealing and fire resistance. A smoke exhaust valve opening is generally set every 60 meters on the flue board, that is, a hole is opened on the flue board to suck the smoke generated by the fire into the flue and discharge it. Except for the smoke exhaust valve openings near the fire being opened, the smoke exhaust valve openings at other positions are closed and sealed to ensure the smoke exhaust effect of the flue.

[0004] At present, all flue boards are made of concrete slabs, and most of them are made into arcs to improve the stress. The cross-section of the smoke exhaust channel is bow-shaped. The longitudinal width of a single flue board along the tunnel is generally the same as the width of the shield segment; the transverse width of the flue board along the tunnel is determined by the area of the smoke exhaust channel and the inner diameter of the shield tunnel segment, generally about 10 meters. The thickness of the ordinary reinforced concrete flue board is at least 0.25 meters. Most of the flue board construction adopts the precast assembly process, and the weight of a single flue board is generally 12 tons, and special lifting equipment is required. Some flue boards are constructed by the cast-in-place process, and scaffolding or formwork trolleys need to be erected inside the shield. The two ends of the flue board along the transverse direction of the tunnel are placed on the corbels, and the corbels are arranged longitudinally along the shield tunnel. Most of the corbel construction adopts the cast-in-place process, and scaffolds need to be set up for formwork support. After the concrete reaches the design strength, the precast flue board is hoisted onto the corbel, and finally the flue board is sealed.

[0005] The existing flue slab structure is that the concrete flue slab is laid on the corbels at both transverse ends of the shield tunnel. The corbels are arranged longitudinally along the shield tunnel. The flue slab can be cast-in-place or precast. The corbels are connected to the segments by drilling holes in the shield segments and implanting steel bars. The problems existing in the existing flue slab structure are as follows: the span of the flue slab is large. For the flue slab of a common one-way three-lane shield tunnel, the transverse span along the tunnel is about 10 meters, resulting in a large thickness of the flue slab, and thus a large weight. The weight of a single-width flue slab with a longitudinal width of 2 meters along the tunnel is about 12 tons. When the precast and assembled construction method is adopted for the flue slab, the hoisting difficulty is high under the condition of limited internal space of the shield; due to the large span of the flue slab, the current flue slabs are mostly made into arcs, increasing the weight and the manufacturing difficulty compared with the flat structure. Moreover, the arch will compress the area of the smoke exhaust channel, and the position of the flue slab needs to be lowered, further increasing the span; to support the high-weight flue slab, the corbels need to be arranged longitudinally along the tunnel, with a large range and a large number of steel bars implanted, seriously damaging the segment structure and having low construction efficiency; for some types of flue slabs, the steel bars cannot penetrate into the corbel concrete, and the connection stability is poor. For some types of flue slabs, the form of temporary corbels needs to be adopted. After the flue slab is erected, the steel bars of the flue slab are penetrated into the corbels, and then the corbel concrete is cast-in-place. This construction method has more construction procedures, and the erection of the flue slab significantly compresses the casting operation space of the corbels, with low construction efficiency. And currently, there are mainly two forms of the connection scheme between the flue slab and the corbel. One is to install temporary steel corbels first. After the precast flue slab is erected, steel bars are welded at the end of the flue slab or connected through reserved steel bar connectors, and the steel bars are connected to the cast-in-place corbel, and then the corbel is cast. This scheme requires the construction of corbels twice, and the process is more cumbersome; the other is that after the cast-in-place corbel is cast, only the flue slab is lapped on the corbel and fixed by post-cast slightly expanded concrete. In this scheme, the flue slab is not rigidly connected to the corbel, and the stability is poor. Summary of the Invention

[0006] Based on this, the purpose of the present invention is to provide an assembled flue slab structure for a shield tunnel with bolt connection. The middle part of the flue slab adopts a flat plate. Compared with the precast arc-shaped flue slab, the setting of the flat plate significantly reduces the thickness and weight of the flue slab; beam members are arranged at both ends of the flue slab, and the beam members of the flue slab are used to bear and transfer the load of the flue slab, and the force transmission route is clear; between adjacent flue slabs and between the flue slab and the corbel, they are all connected by screwing, with good stability and convenient installation.

[0007] A further purpose is to provide a construction method for an assembled flue slab structure for a shield tunnel with bolt connection.

[0008] To solve the problems of the existing technology, the technical solution adopted by the present invention is as follows:

[0009] An assembled flue slab structure for a shield tunnel with bolt connection, comprising a flue slab and a cast-in-place corbel;

[0010] Along the longitudinal direction of the tunnel, the flue duct slab includes a middle flat plate and flue duct slab crossbeams symmetrically and fixedly arranged at both ends of the middle flat plate. A sealing gasket is arranged between adjacent flue duct slabs. A plurality of through holes penetrating the flue duct slab crossbeams are equidistantly arranged on each flue duct slab crossbeam. Longitudinal connecting bolts pass through the through holes of adjacent flue duct slab crossbeams to connect adjacent flue duct slabs;

[0011] Along the longitudinal direction of the tunnel, continuous cast-in-place corbels are provided on the inner walls on both sides of the segment. Each cast-in-place corbel on each inner wall is continuously arranged along the longitudinal direction of the tunnel. Each flue duct slab is lapped on the supports of the cast-in-place corbels on both sides of the segment;

[0012] Embedded chutes for the flue duct slabs are provided on the supports of the cast-in-place corbels on both sides along the longitudinal direction of the tunnel. The bolt head of the first bolt is slidably arranged in the embedded chute. A first bolt hole penetrating the flue duct slab is provided at each end of each flue duct slab along the transverse direction of the tunnel. After the first bolt is aligned with the first bolt hole, the cast-in-place corbel and the flue duct slab are screwed together, and a sealing material is filled at the screwed joint of the cast-in-place corbel and the flue duct slab;

[0013] The gap between the end of the flue duct slab along the transverse direction of the tunnel and the inner wall of the segment is filled with the sealing material.

[0014] Further, a top caulking is provided at the upper end of the connection between adjacent flue duct slabs, and a bottom caulking is provided at the lower end of the connection between adjacent flue duct slabs.

[0015] Further, the top caulking is filled with the sealing material, and the bottom caulking is filled with a fireproof sealing material.

[0016] Further, two limiting plates are symmetrically arranged on both sides of the through hole of each flue duct slab crossbeam at each end of the flue duct slab. Each limiting plate is fixedly connected to the middle flat plate and the flue duct slab crossbeam respectively.

[0017] Further, the flue duct slab is precast, and the middle flat plate, the flue duct slab crossbeam and the limiting plate are integrally precast and cast.

[0018] Further, at least two first bolt holes penetrating the flue duct slab are provided at each end of each flue duct slab along the transverse direction of the tunnel.

[0019] Further, the first bolt holes at each end of each flue duct slab along the transverse direction of the tunnel are symmetrically arranged.

[0020] Further, transverse bars and longitudinal bars arranged along the contour of the flue duct slab are arranged in the flue duct slab, and a steel mesh is arranged in the middle flat plate.

[0021] The present invention also provides a construction method for the prefabricated flue duct slab of a shield tunnel connected by bolts, including the following steps:

[0022] S1. Prefabricated flue duct plates, with a sealing gasket attached to the outer side of the flue duct plate crossbeam of the flue duct plates.

[0023] S2. Cast-in-place corbels are continuously constructed along the longitudinal direction of the tunnel on the segment. The cast-in-place corbels are firmly connected to the segment in the form of implanted steel bars, and embedded chutes are arranged on the cast-in-place corbel supports.

[0024] S3. Lift the flue duct plates, hoist the prefabricated flue duct plates to the preset position. After the first bolts are aligned with the first bolt holes, the cast-in-place corbels are screwed to the flue duct plates, and adjacent flue duct plates are connected by longitudinal connecting bolts.

[0025] S4. At the screwed connection between the cast-in-place corbel and the flue duct plate, the gap between the flue duct plate and the cast-in-place corbel, and the gap between the flue duct plate and the inner wall of the segment are all filled and sealed with filling and plugging materials; the top caulking at the connection of adjacent flue duct plates is plugged with plugging materials, and the bottom caulking at the connection of adjacent flue duct plates is plugged with fireproof sealing materials.

[0026] S5. After the concrete strength reaches the preset strength, remove the formwork of the cast-in-place components to complete the construction.

[0027] The beneficial effects of the present invention compared with the prior art are as follows:

[0028] First, through the prefabricated flue duct plates of the present invention, the middle part of the flue duct plates adopts flat plates, which reduces the hoisting difficulty under the condition of limited internal space of the shield. Compared with the prefabricated arc-shaped flue duct plates, the thickness of the flue duct plates is significantly reduced and the weight is reduced. The flue duct plate crossbeam is used to bear and transfer the load of the flue duct plates, and the force transmission route is clear. The flue duct plates are prefabricated in advance without in-situ casting operations, and the manufacturing difficulty of the flue duct plates is small.

[0029] Second, through the flue duct plate crossbeams arranged at both longitudinal ends of the flue duct along the tunnel, through holes are reserved on the flue duct plate crossbeams, and longitudinal connecting bolts pass through the through holes to connect adjacent two flue duct plates. The adjacent flue duct plates are fastened by the longitudinal connecting bolts, which can effectively improve the integrity of the flue duct. A sealing gasket is arranged between adjacent two flue duct plates, the top caulking is filled and sealed with plugging materials, and the bottom caulking is filled and sealed with fireproof sealing materials to ensure the sealing performance and fire resistance of adjacent two flue duct plates. Mortar and other plugging materials are filled between adjacent limiting plates to cover and plug the longitudinal connecting bolts to improve the fire resistance.

[0030] Thirdly, in the present invention, a first bolt is arranged in a pre-embedded chute in the cast-in-place corbel. The flue duct plate is longitudinally lapped along the tunnel on the cast-in-place corbel support of the tunnel segment. By using the pre-embedded chute, the position of the first bolt can be adjusted. Align the first bolt with the first bolt hole preset on the flue duct plate, and use the first bolt to fasten the flue duct plate and the cast-in-place corbel. After the flue duct plate is assembled once, the bolt connection can be completed. The flue duct plate is rigidly connected to the corbel, and the stability is better. The flue duct plate is longitudinally spliced along the tunnel, effectively improving the stability and sealing performance of the flue duct. The exposed nuts at the screw connection of the cast-in-place corbel and the flue duct plate are filled with sealing materials to improve the durability of the screw connection of the cast-in-place corbel and the flue duct plate. The cast-in-place corbel is arranged in a full length, improving the overall sealing performance of the flue duct;

[0031] Fourthly, in the present invention, by reducing the weight of the flue duct plate, the diameter of the cast-in-place corbel can be reduced, the damage to the segment can be reduced, and at the same time, the hoisting difficulty can be reduced, and the construction is more convenient and fast. This scheme can cope with the positioning influence brought by the curve of the tunnel and the assembly error through the splicing of the flue duct plate, and can rigidly connect the cast-in-place corbel and the flue duct plate accurately, conveniently and quickly. At the same time, the construction process is reduced and the construction efficiency is improved. Brief Description of the Drawings

[0032] Figure 1 is a schematic diagram of the connection structure between the flue duct plate and the cast-in-place corbel provided by the embodiment of the present invention;

[0033] Figure 2 is a schematic cross-sectional view of the flue duct plate provided by the embodiment of the present invention;

[0034] Figure 3 is a schematic plan view of the flue duct plate provided by the embodiment of the present invention;

[0035] Figure 4 is a schematic diagram of the arrangement of the transverse ribs and longitudinal ribs of the flue duct plate provided by the embodiment of the present invention;

[0036] Figure 5 is a construction flow chart provided by the embodiment of the present invention.

[0037] The reference numerals in the drawings are: 1, flue duct plate; 2, cast-in-place corbel; 3, intermediate flat plate; 4, flue duct plate cross beam; 5, sealing gasket; 6, pre-embedded chute; 7, first bolt; 8, first bolt hole; 9, sealing material; 10, top caulking; 11, bottom caulking; 12, segment, 13, longitudinal connecting bolt; 14, limiting plate; 15, transverse rib; 16, longitudinal rib. Detailed Description of the Embodiment

[0038] In order to further understand the features, technical means, specific purposes and functions achieved by the present invention, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0039] Embodiment 1

[0040] Referring to Figures 1 to 4 as shown, a prefabricated flue duct plate structure for a shield tunnel connected by bolts includes a flue duct plate 1 and a cast-in-place corbel 2;

[0041] Along the longitudinal direction of the tunnel, the flue duct plate 1 includes a middle flat plate 3 and flue duct plate crossbeams 4 symmetrically and fixedly arranged at both ends of the middle flat plate 3. A sealing gasket 5 is arranged between adjacent flue duct plates 1. A plurality of through holes penetrating the flue duct plate crossbeams 4 are equidistantly arranged on the flue duct plate crossbeams 4. Longitudinal connection bolts 13 pass through the through holes of adjacent flue duct plate crossbeams 4 to connect the middle parts of adjacent flue duct plates 1 with flat plates. Under the condition of limited internal space in the shield, the hoisting difficulty can be reduced, the diameter of the cast-in-place corbel 2 can be reduced, the damage to the segment 12 can be reduced, and the construction is more convenient and fast. Compared with the precast arc-shaped flue duct plate, the thickness of the flue duct plate 1 is significantly reduced and the weight is reduced. The flue duct plate crossbeams 4 are used to bear and transfer the load of the flue duct plate 1, and the force transmission route is clear. The adjacent flue duct plates 1 are fastened by the longitudinal connection bolts 13, which can effectively improve the integrity of the flue. A sealing gasket 5 is arranged between two adjacent flue duct plates 1 to improve the sealing performance of the flue. The splicing of the flue duct plates 1 can cope with the positioning influence caused by the curve of the tunnel and the assembly error. For two adjacent flue duct plates 1, through the fastening action of the longitudinal connection bolts 12, the sealing gasket 5 between the flue duct plates 1 can be extruded, improving the sealing performance of the flue. The synchronous integral precast pouring of the flue duct plate crossbeams 4 and the middle flat plate 3 improves the stability of the flue duct plate 1. The thickness of the middle flat plate 3 is preferably 70 mm to 110 mm, the width of the flue duct plate crossbeams 4 is preferably 250 to 300 mm, and the height of the flue duct plate crossbeams 4 is preferably 400 to 500 mm. This combination form of the flue duct plate 1 can reduce the weight of the flue duct plate 1 by 30% to 40%. This scheme adopts a beam-slab structure form. Compared with the traditional slab structure form, the calculated span of the force of the traditional simply supported slab can be reduced from 10 m to 1.5 m. And in this scheme, the middle flat plate 3 is preferably a one-way slab, which can transfer the self-weight load and other loads to the flue duct plate crossbeams 4 on both sides. By increasing the height of the flue duct plate crossbeams 4, the bearing capacity of the flue duct plate crossbeams 4 is improved;

[0042] Along the longitudinal direction of the tunnel, continuous cast-in-place corbels 2 are provided on the inner walls on both sides of the segment 12. Each cast-in-place corbel 2 on each inner wall is continuously arranged along the longitudinal direction of the tunnel. Each flue duct plate 1 is lapped on the supports of the cast-in-place corbels 2 on both sides of the segment 12. The continuous arrangement of the cast-in-place corbels 2 improves the overall sealing performance of the flue;

[0043] The cast-in-place corbel 2 supports on both sides along the longitudinal direction of the tunnel are provided with embedded grooves 6 of the flue plate 1, and the bolt head of the first bolt 7 is slidably arranged in the embedded grooves 6. Each flue plate 1 is provided with a first bolt hole 8 penetrating the flue plate 1 at both ends along the transverse direction of the tunnel. After the first bolt 7 is aligned with the first bolt hole 8, the cast-in-place corbel 2 is screwed to the flue plate 1, and the screw connection between the cast-in-place corbel 2 and the flue plate 1 is filled with a plugging material 9. By arranging the first bolt 7 in the embedded groove 6 in the cast-in-place corbel 2, the flue plate 1 is overlapped on the cast-in-place corbel 2 supports of the tunnel segment 12 along the longitudinal direction of the tunnel, and the embedded groove 6 is used to The position of the first bolt 7 can be adjusted, and the first bolt 7 is aligned with the first bolt hole 8 preset on the flue plate 1. The flue plate and the cast-in-place corbel 2 are fastened with the first bolt 7. The bolt connection can be completed after the flue plate 1 is assembled once, which is convenient for the flue plate 1 to be spliced along the longitudinal direction of the tunnel. It can cope with the positioning influence caused by the curve of the tunnel and the assembly error. The cast-in-place corbel 2 and the flue plate 1 can be rigidly connected accurately, conveniently and quickly, and the construction process is reduced, the construction efficiency is improved, and the stability and sealing of the flue are effectively improved. The exposed nuts at the screw connection between the cast-in-place corbel 2 and the flue plate 1 are filled with a sealing material 9 to improve the durability of the screw connection between the cast-in-place corbel 2 and the flue plate 1.

[0044] The gap between the end of the flue plate 1 along the transverse direction of the tunnel and the inner wall of the pipe segment 12 is filled with the plugging material 9. By changing the stress form of the traditional flue plate 1 structure, the traditional plate structure is adjusted to a dense rib beam structure, and the original plate stress is changed to a beam-plate structure. The stress span of the middle plate structure of the beam-plate structure is reduced from the original 10 meters between the transverse tunnel to 1.5 meters between the longitudinal beams of the flue plate 1 along the tunnel, so the bending moment borne by the middle plate 3 is greatly reduced, and the thickness of the middle plate 3 can be significantly reduced to 70mm~110mm. The middle plate 3 transfers the load to the flue plate crossbeams 4 on both sides. By increasing the beam height of the flue plate crossbeams 4, the bearing capacity can be improved. Therefore, by increasing the local structure height, such as the beam height of the flue plate crossbeam 4, the bearing capacity requirements of the flue plate 1 can be met. This type of flue plate 1 structure can make the flue plate 1 lightweight by changing the structural form of the traditional flue plate 1. By changing the traditional flue plate connection form, the flue plate 1 and the cast-in-place corbel 2 connection form, the traditional connection mode is adjusted to bolt connection, and a pre-buried chute 6 is set in the cast-in-place corbel 2. The pre-buried chute 6 is used as a bolt connection device, which can adjust the position of the first bolt 7 along the longitudinal direction of the tunnel to facilitate the alignment and connection of the first bolt 7 with the first bolt hole 8. The prefabricated flue plate 1 has a first bolt hole 8 at the flue plate crossbeam 4. After the flue plate 1 is assembled and bolted, the first bolt hole 8 and the gap are blocked to prevent the first bolt 7 from failing due to heat under fire conditions.

[0045] A top caulking 10 is provided at the upper end of the connection between adjacent flue plates 1 , and a bottom caulking 11 is provided at the lower end of the connection between adjacent flue plates 1 .

[0046] The top caulking joint 10 is filled with the plugging material 9, and the bottom caulking joint 11 is filled with a fireproof sealing material. The plugging material 9 filled in the top caulking joint 10 and the fireproof sealing material filled in the bottom caulking joint 11 ensure the sealing performance and fire resistance of adjacent two flue plates.

[0047] On each end of the flue plate 1, two limiting plates 14 are symmetrically arranged on both sides of the through hole of the flue plate cross beam 4. Each limiting plate 14 is fixedly connected to the middle flat plate 3 and the flue plate cross beam 4 respectively. Mortar and other plugging materials 9 are filled in the adjacent limiting plates 14 to cover and plug the longitudinal connecting bolts 13, improving the fire resistance of the connection part of the flue plate 1 and stabilizing the structure of the flue plate 1.

[0048] The flue plate 1 is prefabricated, and the middle flat plate 3, the flue plate cross beam 4 and the limiting plates 14 are integrally precast and cast. The flue plate 1 is prefabricated in advance without in-situ casting operation, and the manufacturing difficulty of the flue plate 1 is small. The integral setting of the middle flat plate 3, the flue plate cross beam 4 and the limiting plates 14 improves the overall strength of the flue plate 1. Transverse ribs 15 and longitudinal ribs 16 arranged along the contour of the flue plate are arranged in the flue plate 1, and a steel mesh is arranged in the middle flat plate 3. The transverse ribs 15, the longitudinal ribs 16 and the steel mesh strengthen the structural strength of the flue plate 1.

[0049] At least two first bolt holes 8 penetrating through the flue plate 1 are arranged at each end of each flue plate 1 along the transverse direction of the tunnel, that is, there are at least two fixed connection points between the flue plate 1 and the in-situ corbel 2. After the first bolt 7 arranged in the embedded chute 2 is aligned with the first bolt hole 8, the flue plate 1 is lapped on the support of the in-situ corbel 2 to keep stable.

[0050] The first bolt holes 8 at each end of each flue plate 1 along the transverse direction of the tunnel are symmetrically arranged. The symmetrically arranged first bolt holes 8 are conducive to adjusting the position during the splicing of the flue plates 1.

[0051] The present invention realizes the effects of reducing the weight of the flue plate, reducing the hoisting difficulty and reducing the damage to the segments through the structural design and installation process adjustment of the flue plate 1 and the in-situ corbel 2. The main technical measures are as follows:

[0052] 1. After the segments 12 of the shield and the lower structure are constructed, in-situ corbels 2 are continuously constructed along the longitudinal direction of the tunnel on the segments 12. The in-situ corbels 2 are firmly connected to the segments 12 in the form of post-embedded bars. Embedded chutes 6 are reserved on the supports of the in-situ corbels 2, and the bolt heads of the first bolts 7 are placed in the embedded chutes 6 to meet the alignment of the first bolts 7 and the first bolt holes 8 while the flue plate 1 is lapped on the supports of the in-situ corbels 2 in the later stage;

[0053] 2. Fabricate the flue duct slab 1. The flue duct slab 1 is a prefabricated and assembled type. The flue duct slab 1 adopts a beam-slab structure form. On both sides of the flue duct slab 1 along the longitudinal direction of the tunnel, there is a flue duct slab cross beam 4 each. The flue duct slab cross beam 4 is designed to turn up. Between the flue duct slab cross beams 4 is a lightweight intermediate flat plate 3. The flue duct slab cross beam 4 and the intermediate flat plate 3 are precast and cast integrally. A sealing gasket 5 is pre-pasted on the connecting side of the flue duct slab cross beam 4;

[0054] 3. After the cast-in-place corbel 2 reaches the preset strength, hoist and assemble the prefabricated flue duct slab 1. Install the flue duct slab 1, and lap the installed flue duct slab 1 on the cast-in-place corbels 2 symmetrically arranged on both sides of the segment 12. Pass the first bolt 7 through the first bolt hole 8, and complete the rigid connection between the flue duct slab 1 and the cast-in-place corbel 2 through a nut; Adjacent flue duct slabs 1 are spliced. Along the longitudinal direction of the tunnel, the through holes of the flue duct slab cross beams 4 between adjacent flue duct slabs 1 are tightly connected through longitudinal connecting bolts 13;

[0055] 4. Carry out plugging. Use a plugging material 9, preferably mortar or fine aggregate concrete, to fill and seal the exposed nuts at the screwed connection between the cast-in-place corbel 2 and the flue duct slab 1. Fill the space between the flue duct slab 1 and the segment 12 with the plugging material 9, preferably fine aggregate concrete. The top joint 10 between adjacent flue duct slabs 1 is filled and sealed with the plugging material 9, preferably mortar or fine aggregate concrete. The bottom joint 11 between adjacent flue duct slabs 1 is filled and sealed with a fireproof sealing material;

[0056] After the concrete strength reaches the preset strength, remove the formwork of the cast-in-place component to complete the construction.

[0057] The present invention utilizes the design of the embedded chute 6 of the cast-in-place corbel 2, the prefabricated flue duct slab 1, the flue duct slab cross beam 4, etc., which can improve the structural stability of the flue duct slab 1, reduce the damage to the segment 12, and overall improve the disaster prevention ability of the tunnel.

[0058] In the present invention, the cast-in-place corbel 2 is poured first, and then the flue duct slab 1 is hoisted. The middle part of the prefabricated flue duct slab 1 adopts an intermediate flat plate 3, which reduces the hoisting difficulty under the condition of limited internal space of the shield. The manufacturing difficulty of the flue duct slab 1 is small, it is convenient to assemble, and the weight of the flue duct slab 1 is reduced. The present invention solves the problems in the existing installation that in order to improve the utilization space of the cross section of the shield tunnel, the arc-shaped flue duct slab is heavy, resulting in large corbel sizes and high hoisting difficulty, and the flue duct slab needs to be determined considering the assembly error of the shield construction and the curved structure of the tunnel.

[0059] After the first bolt hole 8 on the flue duct plate 1 is aligned with the first bolt 7 on the cast-in-place corbel 2, the flue duct plate 1 and the cast-in-place corbel 2 are completed with screw connection. The flue duct plate 1 and the cast-in-place corbel 2 are rigidly connected, and the stability is better. The screw connection part between the flue duct plate 1 and the cast-in-place corbel 2 is filled with a sealing material 9, and the sealing material 9 presses the first bolt 7 into the embedded chute 6. The gap between the end of the flue duct plate 1 along the transverse direction of the tunnel and the inner wall of the segment 12 is filled with the sealing material 9 to strengthen the connection and fixation between the flue duct plate 1 and the cast-in-place corbel 2. Under the fire condition, adjacent flue duct plates 1 are connected by longitudinal connection bolts 13. When the flue duct plate is damaged, the flue duct structure is affected by the longitudinal connection bolts 13, and it can be damaged but not collapse, avoiding the segment 12 structure at the top of the shield being directly affected by the fire.

[0060] The flue duct plate 1 is supported by the cast-in-place corbel 2, and the cast-in-place corbel 2 and the flue duct plate 1 are rigidly connected. Compared with the traditional splicing method of the flue duct plate in the existing scheme, the stress form of the traditional flue duct plate structure is changed, and the traditional plate structure is adjusted to a ribbed beam structure, which can effectively reduce the self-weight of the flue duct plate 1 by 30% - 40%. After reducing the self-weight, not only can the material consumption be reduced, but the cast-in-place corbel 2 is arranged longitudinally along the tunnel in a continuous length, and the segment 12 of the shield is stressed evenly, thereby reducing the permanent damage to the structure of the segment 12 of the shield and reducing the structural hidden danger. Moreover, it is more convenient for hoisting and assembling operations, greatly improving the operation efficiency; the splicing method of the flue duct plate 1 adjusts the existing lap bar connection method to the longitudinal connection bolt 13 connection, improving the connection stability between the flue duct plates 1, reducing the construction difficulty of the connection between the flue duct plate 1 and the cast-in-place corbel 2, and being able to effectively improve the construction efficiency and assembly quality of the flue duct plate assembly; through the fastening action of the longitudinal connection bolts 13 between the flue duct plates 1, the sealing effect between the flue duct plates 1 can be improved, and the smoke exhaust efficiency can be improved; the force transmission path of the whole system is clear, the material performance is fully exerted, the connection is firm, the sealing is good, it is convenient for construction and reduces the project cost.

[0061] The present invention mainly includes main components such as the flue duct plate 1 and the cast-in-place corbel 2. The specific structure and construction method are as follows:

[0062] First, prefabricate the flue duct plate 1 in the factory. The middle flat plate 3 of the flue duct plate 1 is a lightweight flat plate. Symmetrical first bolt holes 8 are opened at both ends of the middle flat plate 3 along the transverse direction of the tunnel. Flue duct plate cross beams 4 are arranged on both sides of the two ends of the middle flat plate 3 along the longitudinal direction of the tunnel. Through holes for the longitudinal connection bolts 13 to pass through are equidistantly opened on the flue duct plate cross beams 4. Limiting plates 14 are arranged on both sides of each through hole. The middle flat plate 3, the flue duct plate cross beams 4 and the limiting plates 14 are integrally precast and poured. A sealing gasket 5 is attached to the outside of the flue duct plate cross beam 4 of the flue duct plate 1. After the prefabrication of the flue duct plate 1 is completed, it is transported to the site for storage;

[0063] Second, continuously construct and set the cast-in-place corbel 2 along the longitudinal direction of the tunnel. A preset embedded chute 6 is arranged on the support of the cast-in-place corbel 2, and the first bolt 7 is placed in the embedded chute 6;

[0064] III. Hoist the flue duct slab 1 to the position prepared for installation, with the hoisting height slightly higher than the theoretical installation position. Slide the first bolt 7 to align the first bolt hole 8 with the first bolt 7 and splice the adjacent flue duct slabs 1. After the splicing of the adjacent flue duct slabs 1 is completed, fasten and connect them through the first bolt 7 and the nut to complete the rigid connection between the cast-in-place corbel 2 and the flue duct slab 1. The adjacent flue duct slabs 1 are tightly connected through the longitudinal connection bolts 13;

[0065] IV. Carry out filling. The joint between the cast-in-place corbel 2 and the flue duct slab 1 is sealed with a sealing material 9, preferably mortar or fine aggregate concrete. The gap between the end of the flue duct slab 1 along the transverse direction of the tunnel and the inner wall of the segment 12 is filled with the sealing material 9, preferably fine aggregate concrete. The top joint 10 between the adjacent flue duct slabs 1 is sealed with the sealing material 9, preferably mortar or fine aggregate concrete. The bottom joint 11 between the adjacent flue duct slabs 1 is sealed with a fireproof sealing material, preferably fireproof putty, to complete the installation of the flue duct slab;

[0066] V. Carry out structural sealing treatment on the flue duct slab 1, cast-in-place corbel 2, etc. to complete the construction.

[0067] Embodiment 2

[0068] The second embodiment of the present invention provides a construction method for the installation structure of the flue duct slab in a shield tunnel, as Figure 5 shown. The construction sequence of the structure is as follows:

[0069] The first step: Prefabricate the flue duct slab 1, and attach a sealing gasket 5 to the outside of the flue duct cross beam 4 of the flue duct slab 1;

[0070] The second step: Construct and set the cast-in-place corbel 2 continuously along the longitudinal direction of the tunnel on the segment 12. The cast-in-place corbel 2 is firmly connected to the segment 12 in the form of implanted bars, and an embedded chute 6 is arranged on the support of the cast-in-place corbel 2;

[0071] The third step: Hoist the flue duct slab 1, hoist the prefabricated flue duct slab 1 to the preset position. After the first bolt 7 is aligned with the first bolt hole 8, the cast-in-place corbel 2 is screwed to the flue duct slab 1, and the adjacent flue duct slabs 1 are connected through the longitudinal connection bolts 13;

[0072] The fourth step: The joint between the cast-in-place corbel 2 and the flue duct slab 1, the gap between the flue duct slab 1 and the cast-in-place corbel 2, and the gap between the flue duct slab 1 and the inner wall of the segment 2 are all filled and sealed with the filling and sealing material 9; the top joint 10 at the connection of the adjacent flue duct slabs 1 is sealed with the sealing material 9, and the bottom joint 11 at the connection of the adjacent flue duct slabs 1 is sealed with a fireproof sealing material;

[0073] The fifth step: After the concrete strength reaches the preset strength, remove the formwork of the cast-in-place component to complete the construction.

[0074] The above embodiments only represent one or several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. A bolt-connected precast flue slab structure for shield tunnels, characterized in that: It includes a flue duct plate (1) and a cast-in-place corbel (2); Along the longitudinal direction of the tunnel, the flue duct plate (1) includes a middle flat plate (3) and flue duct plate crossbeams (4) symmetrically and fixedly arranged at both ends of the middle flat plate (3). A sealing gasket (5) is arranged between adjacent flue duct plates (1). A plurality of through holes penetrating the flue duct plate crossbeam (4) are equidistantly arranged on the flue duct plate crossbeam (4), and longitudinal connection bolts (13) pass through the through holes of adjacent flue duct plate crossbeams (4) to connect adjacent flue duct plates (1); Along the longitudinal direction of the tunnel, continuous cast-in-place corbels (2) are provided on the inner walls on both sides of the segment (12). Each cast-in-place corbel (2) on each inner wall is continuously arranged along the longitudinal direction of the tunnel, and each flue duct plate (1) is lapped on the supports of the cast-in-place corbels (2) on both sides of the segment (12); Embedded chutes (6) of the flue duct plate (1) are provided on the supports of the cast-in-place corbels (2) on both sides along the longitudinal direction of the tunnel. The bolt head of the first bolt (7) is slidably arranged in the embedded chute (6). Through first bolt holes (8) penetrating the flue duct plate (1) are provided at both ends of each flue duct plate (1) along the transverse direction of the tunnel. After the first bolt (7) is aligned with the first bolt hole (8), the cast-in-place corbel (2) is screwed to the flue duct plate (1), and a sealing material (9) is filled at the screwed joint of the cast-in-place corbel (2) and the flue duct plate (1); The gap between the end of the flue duct plate (1) along the transverse direction of the tunnel and the inner wall of the segment (12) is filled with the sealing material (9); A top caulking (10) is arranged at the upper end of the joint of adjacent flue duct plates (1), and a bottom caulking (11) is arranged at the lower end of the joint of adjacent flue duct plates (1); The top caulking (10) is filled with the sealing material (9), and the bottom caulking (11) is filled with a fireproof sealing material; Two limiting plates (14) are symmetrically arranged on both sides of the through hole of each flue duct plate crossbeam (4) at each end of the flue duct plate (1), and each limiting plate (14) is fixedly connected to the middle flat plate (3) and the flue duct plate crossbeam (4) respectively; The flue duct plate (1) is precast, and the middle flat plate (3), the flue duct plate crossbeam (4) and the limiting plate (14) are integrally precast and poured; Transverse bars (15) and longitudinal bars (16) arranged along the contour of the flue duct plate are arranged in the flue duct plate (1), and a steel mesh is arranged in the middle flat plate (3).

2. The bolt-connected prefabricated flue slab structure for shield tunnels according to claim 1, wherein: At least two first bolt holes (8) penetrating the flue duct plate (1) are arranged at each end of each flue duct plate (1) along the transverse direction of the tunnel.

3. The bolt-connected prefabricated flue slab structure for shield tunnels according to claim 2, characterized in that: The first bolt holes (8) at each end of each flue duct plate (1) along the transverse direction of the tunnel are symmetrically arranged.

4. A construction method of a bolt-connected prefabricated flue duct plate structure for a shield tunnel according to claim 1, characterized in that: S1. Prefabricate the flue duct plate (1), and attach a sealing gasket (5) to the outer side of the flue duct plate crossbeam (4) of the flue duct plate (1); S2. Continuously construct cast-in-place corbels (2) along the longitudinal direction of the tunnel on the segment (12). At the cast-in-place corbels (2), use the form of post-embedded bars to firmly connect the cast-in-place corbels (2) to the segment (12). An embedded chute (6) is provided on the support of the cast-in-place corbel (2); S3. Lift the flue gas slab (1), hoist the precast flue gas slab (1) to the preset position. After the first bolt (7) is aligned with the first bolt hole (8), the cast-in-place corbel (2) is screwed to the flue gas slab (1), and adjacent flue gas slabs (1) are connected by longitudinal connecting bolts (13); S4. At the screwed connection between the cast-in-place corbel (2) and the flue gas slab (1), the gap between the flue gas slab (1) and the cast-in-place corbel (2), and the gap between the flue gas slab (1) and the inner wall of the segment (12) are all filled and sealed with a filling and sealing material (9); The top caulking (10) at the connection of adjacent flue gas slabs (1) is sealed with a sealing material (9), and the bottom caulking (11) at the connection of adjacent flue gas slabs (1) is sealed with a fireproof sealing material; S5. After the concrete strength reaches the preset strength, remove the formwork of the cast-in-place component to complete the construction.

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