阅读说明：本技术 一种盾构隧道装配式轨顶风道结构 (Shield tunnel assembled rail top air duct structure ) 是由 张继清 宋乐阳 张春雷 王达麟 崔涛 宋冉 王秀妍 徐振艳 刘惠敏 张福麟 王一 于 2021-08-17 设计创作，主要内容包括：本发明提供一种盾构隧道装配式轨顶风道结构,包括预制风道板、预制竖向隔墙、π型连接件和钢牛腿连接件,预制风道板水平设置,预制竖向隔墙竖直装配于预制风道板上方,π型连接件装配于预制竖向隔墙上方并用于与隧道内管片进行连接,钢牛腿连接件装配于预制风道板一端并用于与隧道内管片进行连接。本发明能够避免传统现浇施工需钻孔植筋破坏管片结构的缺点,通过预制部件装配设计,实现了不损害管片结构并加快安装速度的目的。(The invention provides an assembled type rail top air duct structure of a shield tunnel, which comprises a prefabricated air duct plate, a prefabricated vertical partition wall, a pi-shaped connecting piece and a steel bracket connecting piece, wherein the prefabricated air duct plate is horizontally arranged, the prefabricated vertical partition wall is vertically assembled above the prefabricated air duct plate, the pi-shaped connecting piece is assembled above the prefabricated vertical partition wall and used for being connected with a duct piece in the tunnel, and the steel bracket connecting piece is assembled at one end of the prefabricated air duct plate and used for being connected with the duct piece in the tunnel. The cast-in-place construction method can avoid the defect that the structure of the duct piece is damaged by drilling and bar planting in the traditional cast-in-place construction, and achieves the purposes of not damaging the structure of the duct piece and accelerating the installation speed through the assembly design of the prefabricated parts.)

1. The utility model provides a shield tunnel assembled railhead wind channel structure, including prefabricated wind channel board (1), prefabricated vertical partition wall (2), pi type connecting piece (3) and steel corbel connecting piece (4), prefabricated wind channel board (1) level sets up, prefabricated vertical partition wall (2) are vertical to be assembled in prefabricated wind channel board (1) top, pi type connecting piece (3) are assembled in prefabricated vertical partition wall (2) top and are used for being connected with section of jurisdiction in the tunnel, steel corbel connecting piece (4) are assembled in prefabricated wind channel board (1) one end and are used for being connected with section of jurisdiction in the tunnel.

2. The shield tunnel assembled type rail-top air channel structure according to claim 1, wherein strip-shaped bolt holes (12) capable of adjusting errors are formed in the pi-shaped connecting piece (3) and the steel corbel connecting piece (4); t-shaped sleeves (5) for connection are pre-buried in the tunnel pipe pieces.

3. The shield tunnel assembled type rail-top air duct structure of claim 1, wherein the prefabricated air duct plate (1) is L-shaped, UHPC ultrahigh-performance concrete material is adopted, the thickness of the long side of the L-shaped is 1/3-1/2 of the common cast-in-place rail-top air duct structure, the local thickening of the L-shaped short side is used for installing a shield door, and an embedded sleeve (6) which is respectively connected with the prefabricated vertical partition wall (2) and the steel bracket connecting piece (4) is arranged in the prefabricated air duct plate (1).

4. The shield tunnel assembled type rail-top air duct structure of claim 1, wherein the prefabricated vertical partition wall (2) is in an inverted T shape, UHPC ultrahigh-performance concrete materials are adopted, the thickness of a long side of the T shape is 1/3-1/2 of the common cast-in-place rail-top air duct structure, the short side of the T shape is locally thickened, and an embedded sleeve (6) used for being connected with the pi-shaped connecting piece (3) and the prefabricated air duct plate (1) is arranged in the prefabricated vertical partition wall (2).

5. The shield tunnel assembled type rail-top air duct structure of claim 1, wherein the pi-shaped connecting piece (3) comprises an arc-shaped base (8) for connecting with a duct piece, a vertical hanging wall (9) is arranged below the arc-shaped base (8), and the vertical hanging wall (9) is connected with the arc-shaped base (8) through an inclined strut (11) to increase the stress of the structure; the vertical wall (9) is positioned at a part slightly deviated from one side of the middle part below the arc-shaped base (8); the prefabricated vertical partition walls (2) can be inserted and fixed between the vertical walls (9).

6. The shield tunnel assembled rail-top duct structure according to claim 5, characterized in that the outer side of the vertical hanging wall (9) is provided with a longitudinal connecting plate (13), and the prefabricated vertical partition wall (2) is clamped and fixed between the vertical hanging wall (9) and the longitudinal connecting plate (13) through fastening connecting pieces; tooth grooves (15) capable of being meshed with each other are arranged on the surfaces of the vertical wall (9) and the longitudinal connecting plate (13) which are contacted with each other; the fastening connecting piece is a connecting bolt (7) and a double anti-loose nut (17) which can be matched with the other end of the connecting bolt; a strip bolt hole (12) capable of adjusting errors is arranged on the vertical wall (9); two pi-shaped connecting pieces (3) are arranged on each ring pipe sheet in parallel along the longitudinal connecting plate; the pi-shaped connecting piece (3) is formed by welding Q355B steel plates, the joint is fully welded, and the surface is subjected to anticorrosion and fireproof treatment.

7. The shield tunnel assembled type track top air duct structure according to claim 1, wherein the steel bracket connecting piece (4) comprises an arc-shaped base (8) used for being connected with a tunnel inner duct piece, one side of the arc-shaped base (8) is connected with a horizontal cross arm (10), and one side below the horizontal cross arm (10) is provided with an inclined strut (11) connected with the arc-shaped base (8); the horizontal cross arm (10) is positioned at a part slightly deviated downwards from the middle part of one side of the arc-shaped base (8); one end of the prefabricated air duct plate (1) is fixed on the horizontal cross arm (10).

8. The shield tunnel assembled type rail top air duct structure according to claim 7, wherein a horizontal base plate (14) is arranged above the horizontal cross arm (10), and the prefabricated air duct plate (1) is sequentially fixed on the horizontal base plate (14) and the horizontal cross arm (10) through fastening connecting pieces; the fastening connecting piece is a connecting bolt (7) and a double anti-loosening nut (17) which can be matched with the connecting bolt at the other end of the connecting bolt, a bolt fastening steel base plate (18) is further arranged between the double anti-loosening nut (17) and the horizontal cross arm (10), and tooth grooves (15) which can be meshed with each other are formed in the surfaces of the bolt fastening steel base plate (18) and the horizontal cross arm (10) which are in mutual contact; two steel corbel connecting pieces (4) are arranged on each ring pipe sheet in parallel along the horizontal base plate; the steel bracket connecting piece (4) is formed by welding Q355B steel plates, seams are fully welded, the surface is subjected to anticorrosion and fireproof treatment, and the section of the horizontal cross arm (10) is U-shaped.

Technical Field

The invention belongs to the field of building construction, and particularly relates to an assembled rail top air duct structure of a shield tunnel.

Background

At present, subway stations in urban rail transit construction in China are mainly constructed by an open cut method, and section tunnels are mainly constructed by a shield method. Due to various factors such as land acquisition and removal, traffic dispersion and the like, special conditions that a station is built by adopting a shield method in a matched manner may occur. The shield station is a side platform station consisting of two parallel circular tunnels, is rarely applied at present in China, generally adopts a large-diameter (more than 6 meters) shield machine, lays a track and sets internal structures such as a station platen and a track top air duct in the shield tunnel in a mode of firstly tunneling and then tunneling, and passengers enter the platform from vertical shafts at two ends of the station to take a bus.

The rail top air duct is an air exhaust channel in a station, is suspended at the joint of the middle plate and the structural side wall, and is mainly constructed by a cast-in-place method in China. However, when the tunnel top air duct structure is arranged at a shield station, if the traditional cast-in-place mode is adopted for construction, holes are drilled and steel bars are needed to be planted on the tunnel duct pieces, the construction period is long, the construction quality is difficult to guarantee, and adverse effects are generated on the durability of the structure.

At present, a large number of prefabricated structures are adopted in domestic construction engineering, and the prefabricated members are transported to the site for assembly, so that the installation is simple, and the construction speed is high. Therefore, it is necessary to provide a fully-assembled rail top air duct structure adopting prefabricated parts for the condition of arranging a rail top air duct secondary structure in an existing shield tunnel, so as to avoid the damage of drilling and bar planting to the tunnel structure.

Disclosure of Invention

The invention provides a shield tunnel assembly type rail top air duct structure for solving the problems in the prior art, and aims to provide a shield tunnel assembly type rail top air duct structure which can avoid the defect that a duct piece structure is damaged by drilling and bar planting in the traditional cast-in-place construction method, and achieve the purposes of not damaging the duct piece structure and accelerating the installation speed through the assembly design of prefabricated parts.

The assembled type rail top air duct structure of the shield tunnel comprises a prefabricated air duct plate, prefabricated vertical partition walls, pi-shaped connecting pieces and steel bracket connecting pieces, wherein the prefabricated air duct plate is horizontally arranged, the prefabricated vertical partition walls are vertically assembled above the prefabricated air duct plate, the pi-shaped connecting pieces are assembled above the prefabricated vertical partition walls and are used for being connected with duct pieces in the tunnel, and the steel bracket connecting pieces are assembled at one end of the prefabricated air duct plate and are used for being connected with duct pieces in the tunnel.

The pi-shaped connecting piece and the steel bracket connecting piece are provided with strip-shaped bolt holes capable of adjusting errors; t-shaped sleeves for connection are pre-buried in the tunnel pipe pieces.

The prefabricated air duct plate is L-shaped, an UHPC (ultra high performance concrete) material is adopted, the thickness of a long edge of the L-shaped air duct plate is 1/3-1/2 of the structure of a common cast-in-place rail top air duct, the local thickening of a short edge of the L-shaped air duct plate is used for installing a shielding door, and an embedded sleeve which is respectively connected with a prefabricated vertical partition wall and a steel bracket connecting piece is arranged in the prefabricated air duct plate.

The prefabricated vertical partition wall is inverted T-shaped, an UHPC (ultra high performance concrete) material is adopted, the thickness of a long side of the T-shaped partition wall is 1/3-1/2 of the structure of a common cast-in-place rail top air duct, the local thickness of a short side of the T-shaped partition wall is thickened, and embedded sleeves used for being connected with a Pi-shaped connecting piece and a prefabricated air duct plate respectively are arranged in the prefabricated vertical partition wall.

The n-shaped connecting piece comprises an arc-shaped base used for being connected with the tunnel inner tube sheet, a vertical hanging wall is arranged below the arc-shaped base, and the vertical hanging wall is connected with the arc-shaped base through an inclined strut to increase structural stress; (ii) a The vertical wall is positioned at a part slightly deviated from one side of the middle part below the arc-shaped base; the prefabricated vertical partition walls can be inserted and fixed between the vertical walls.

Furthermore, a longitudinal connecting plate is arranged on the outer side of the vertical wall, and the prefabricated vertical partition wall is clamped and fixed between the vertical wall and the longitudinal connecting plate through a fastening connecting piece; tooth sockets capable of being meshed with each other are arranged on the surfaces of the vertical wall and the longitudinal connecting plate, which are contacted with each other; the fastening connecting piece is a connecting bolt and a double anti-loose nut which can be matched with the connecting bolt at the other end of the connecting bolt; the vertical wall is provided with a strip bolt hole capable of adjusting errors; two pi-shaped connecting pieces are arranged on each ring pipe sheet in parallel along the longitudinal connecting plate; the pi-shaped connecting piece is formed by welding Q355B steel plates, the seam is fully welded, and the surface is subjected to anticorrosion and fireproof treatment.

The steel bracket connecting piece comprises an arc-shaped base used for being connected with the tunnel inner pipe piece, one side of the arc-shaped base is connected with a horizontal cross arm, and an inclined strut connected with the arc-shaped base is arranged below the horizontal cross arm; the horizontal cross arm is positioned at the part slightly deviated downwards from the middle part of one side of the arc-shaped base; one end of the prefabricated air duct plate is fixed on the horizontal cross arm.

Furthermore, a horizontal base plate is arranged above the horizontal cross arm, and the prefabricated air duct plate is sequentially fixed on the horizontal base plate and the horizontal cross arm through fastening connecting pieces; the fastening connecting piece is a connecting bolt and a double anti-loose nut which can be matched with the connecting bolt at the other end of the connecting bolt, a bolt fastening steel base plate is further arranged between the double anti-loose nut and the horizontal cross arm, and tooth grooves which can be meshed with each other are arranged on the surfaces of the bolt fastening steel base plate and the horizontal cross arm which are contacted with each other; two steel corbel connecting pieces are arranged on each ring pipe piece in parallel along the horizontal base plate; the steel bracket connecting piece is formed by welding Q355B steel plates, seams are fully welded, the surface is subjected to anticorrosion and fireproof treatment, and the cross section of the horizontal cross arm is U-shaped.

Compared with the prior art, the invention adopts the structural design of the fully-assembled rail top air channel, all components can be prefabricated in a factory, the prefabricated components are produced by adopting ultra-high performance concrete materials, the strength is high, the durability is good, the thickness can be greatly reduced compared with the common cast-in-place structure, and the materials are saved. All joint parts are fixedly connected through bolts and sleeves, the installation is convenient and fast, the connection is reliable, and the damage of drilling and bar planting to the pipe sheet structure in the traditional cast-in-place mode is avoided. In the invention, each part is convenient to replace, and after a certain part is damaged, the part can be replaced by dismounting the bolt, so that good working performance can be always kept. The invention has stable assembly structure, reasonable structural balance weight, high connection reliability, good safety and capability of bearing the air pressure of a train in high-speed operation.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic cross-sectional view of the deployment of a fabricated rail-top duct in a shield tunnel station;

FIG. 2 is a schematic view of a prefabricated air duct panel according to the present invention;

FIG. 3 is a schematic view of a prefabricated vertical partition according to the present invention;

FIG. 4 is a schematic view of a pi connector according to the present invention;

FIG. 5 is a schematic view of a steel corbel connector according to the present invention;

FIG. 6 is a schematic view showing a structure of a T-shaped sleeve embedded in a duct piece and a sleeve embedded in a member according to the present invention;

FIG. 7 is a schematic view of the locking double nut of the present invention in connection with a structural member;

FIG. 8 is a schematic view of a longitudinal web according to the present invention;

FIG. 9 is a schematic view of a horizontal shim plate according to the present invention;

FIG. 10 is a schematic view of the vertical connection joint of the single ring segment inner rail top duct structure and the segment of the present invention;

FIG. 11 is a schematic view of the horizontal connection joint between the single ring segment inner rail top duct structure and the segment of the present invention;

FIG. 12 is a schematic view of the assembled rail top duct structure of the present invention showing the connection of the structural members;

FIG. 13 is a schematic view of a fabricated rail-top duct structure in a shield tunnel according to the present invention;

fig. 14 is a structural schematic diagram of the assembled rail top air duct structure in the shield tunnel in the application state.

Wherein the content of the first and second substances,

1 prefabricated air duct board 2 prefabricated vertical partition wall

3 pi type connecting piece 4 steel bracket connecting piece

5T type sleeve 6 pre-buried sleeve

7 connecting bolt 8 arc base

9 vertical arm 10 horizontal cross arm

11 bracing 12 bar bolt holes

13 longitudinal connecting plate 14 horizontal backing plate

15 tooth socket 16 segment ring

17 locking double nut 18 bolt fastening steel backing plate

Detailed Description

For a better understanding of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawings. Technical terms used in the following description have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention belongs. The accompanying examples, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to explain the principles of the invention.

Fig. 1 is a schematic cross-sectional view of the arrangement of the fabricated rail-top duct of the present invention in a shield tunnel station. The air duct structure is fixed at the top of the shield tunnel and is fixedly connected with the shield tunnel through a T-shaped sleeve 5. In a specific embodiment, the inner diameter of the shield tunnel segment lining is 7.7m, the outer diameter is 8.5m, the breadth is 1.5m, a blocking mode of 1 top sealing block (F) +2 adjacent blocks (L1, L2) +4 standard blocks (B1, B2, B3 and B4) is adopted, and the air duct structure is respectively connected with the adjacent blocks L2 and the standard blocks B4. The air duct structural member comprises a prefabricated air duct plate 1, prefabricated vertical partition walls 2, pi-shaped connecting pieces 3 and steel corbel connecting pieces 4, the prefabricated air duct plate 1 is horizontally arranged, the prefabricated vertical partition walls 2 are vertically assembled above the prefabricated air duct plate 1, the pi-shaped connecting pieces 3 are assembled above the prefabricated vertical partition walls 2 and used for being connected with an adjacent block L2, and the steel corbel connecting pieces 4 are assembled at one end of the prefabricated air duct plate 1 and used for being connected with a standard block B4.

As shown in figure 2, prefabricated air duct board 1 is L shape, adopts UHPC ultrahigh performance concrete material, and intensity is high, the durability is good, and the long limit thickness of L shape only is 1/3 ~ 1/2 of general cast-in-place rail top air duct structure, can greatly alleviate the structure dead weight, and the L shape minor face is installation shield door local thickening for the L shape minor face design of installation shield door can combine the shield door to carry out the auxiliary stay to the air duct structure, maintains the overall stability of air duct structure. And an embedded sleeve 6 is further arranged in the L-shaped long edge so as to facilitate later-stage bolt connection, wherein four embedded sleeves 6 are embedded at the joint of the L-shaped long edge and the steel bracket connecting piece 4, and six embedded sleeves 6 are embedded at the joint of the L-shaped long edge and the prefabricated vertical partition wall 2. As an optimized size design, the length of the long L-shaped edge of the prefabricated air duct plate 1 is 3520mm +550mm, the longitudinal width of the prefabricated air duct plate along the tunnel is 1496mm, 4mm manufacturing and assembling errors are reserved, and the thickness of the prefabricated air duct plate is 70 mm. The pre-buried sleeve 6 may be an M16 sleeve.

As shown in fig. 3, the prefabricated vertical partition wall 2 is in an inverted T shape, a UHPC ultrahigh-performance concrete material is adopted, the thickness of a long side of the T shape is only 1/3-1/2 of the structure of a common cast-in-place rail top air duct, the dead weight of the structure can be greatly reduced, the short side of the T shape is appropriately thickened, embedded sleeves 6 are further arranged in the long side of the T shape and the short side of the T shape so as to be connected with later-stage bolts, six embedded sleeves 6 are embedded at the joint of the T-shaped connecting piece 3, and six embedded sleeves 6 are embedded at the joint of the prefabricated air duct board 1. As an optimized size design, the height of the inverted T-shaped prefabricated vertical partition wall 2 is 1610mm, the width of a short side of the T-shaped prefabricated vertical partition wall is 330mm, the longitudinal length of the tunnel is 1496mm, manufacturing and assembling errors of 4mm are reserved, and the thickness is 60 mm. The pre-buried sleeve 6 may be an M16 sleeve.

As shown in figure 4, the pi-shaped connecting piece 3 is formed by welding Q355B steel plates, seams are fully welded, the surface is subjected to corrosion prevention and fire prevention treatment, and the strength and the durability are high. The pi-shaped connecting piece 3 comprises an arc-shaped base 8, a group of vertical walls 9 are arranged below the arc-shaped base 8, and inclined struts 11 connected with the arc-shaped base 8 are respectively arranged on two sides of each vertical wall 9 and used for increasing the bending and pulling resistance of the connecting piece. The vertical hanging wall 9 is positioned at a position slightly deviated from the middle part below the arc-shaped base 8 to one side. Be equipped with bar bolt hole 12 on the arc base 8, bar bolt hole 12 center corresponds with pre-buried T type sleeve 5 position in the section of jurisdiction basically, and the suitable hole site dislocation of adjusting during the installation is fixed through connecting bolt 7, can realize the accurate connection of pi type connecting piece 3 on the section of jurisdiction. The vertical wall 9 is also correspondingly provided with a strip bolt hole 12, the center of the strip bolt hole basically corresponds to the position of the embedded sleeve 6 in the prefabricated vertical partition wall, the strip bolt hole can be adjusted up and down to be accurately positioned during installation and construction, and the prefabricated vertical partition wall 2 is fixedly connected to the pi-shaped connecting piece 3 through the connecting bolt 7. In order to further improve the connection stability of the prefabricated vertical partition wall 2 on the pi-shaped connecting piece 3, a longitudinal connecting plate 13 is additionally arranged on the outer side of the vertical wall 9, and a circular bolt hole is formed in the longitudinal connecting plate 13. When the prefabricated vertical partition wall 2 is installed, the connecting bolt 7 sequentially penetrates through the bolt hole of the longitudinal connecting plate, the strip-shaped bolt hole 12 in the vertical arm of the connecting piece and the embedded sleeve 6 in the component and then is fastened and positioned. The surfaces of the vertical hanging wall 9 and the longitudinal connecting plate 13 which are contacted with each other are also provided with matched tooth grooves 15, and the locking of the positions is ensured through the engagement of the tooth grooves. As an optimized size design, the thickness of a steel plate of the pi-shaped connecting piece 3 is 15mm, the aperture of the strip-shaped bolt hole 12 is 18mm, the hole length is 36mm, and errors can be adjusted during installation so as to realize accurate positioning of the partition wall.

As shown in fig. 5, the steel corbel connecting piece 4 is formed by welding Q355B steel plates, seams are welded fully, the surface is subjected to corrosion prevention and fire prevention treatment, the strength is high, and the durability is good, the steel corbel connecting piece 4 comprises an arc-shaped base 8, a horizontal cross arm 10 is connected to one side of the arc-shaped base 8, and an inclined strut 11 connected with the arc-shaped base 8 is arranged on one side below the horizontal cross arm 10 and used for stably supporting the horizontal cross arm 10. The arc-shaped base 8 in the steel corbel connecting piece 4 and the arc-shaped base 8 on the pi-shaped connecting piece 3 have the same structure, and the same structural component can be applied to different structural members. The arc-shaped base 8 of the steel bracket connecting piece is also provided with a strip-shaped bolt hole 12 for realizing the connection and fixation with the duct piece. Also be equipped with a plurality of bar bolt holes 12 on the horizontal cross arm 10, bar bolt hole 12 center corresponds with prefabricated air duct inboard pre-buried sleeve 6 position, and the accessible is controlled in the adjustment accurate positioning during installation construction, and the rethread connecting bolt 7 realizes the fixed of prefabricated air duct board. The horizontal cross arm 10 is made of U-shaped channel steel, and can improve the erection stability and the structural rigidity. In order to further improve the connection stability, a horizontal base plate 14 is additionally arranged between the prefabricated air duct plate 1 and the steel corbel connecting pieces, round bolt holes for bolt connection are formed in the horizontal base plate 14, and at least two steel corbel connecting pieces are arranged on each ring pipe piece. The inclined strut 11 of the steel corbel connecting piece 4 may be the same as the inclined strut 11 of the pi-shaped connecting piece 3, may be applied to different structural members as the same structural component, and may also be different, for example, the inclined strut 11 of the steel corbel connecting piece 4 may be integrally formed with the horizontal cross arm 10, and may have various implementation manners by conventional means, and it is easy to understand and is not described in detail. As an optimized size design, the thickness of the steel plate of the steel bracket connecting piece 4 is 15 mm. The strip bolt holes 12 on each structural member in the invention can have the same structure and size, and can also be set to different sizes according to requirements, but can achieve the purposes of adjusting errors and accurately positioning.

As shown in fig. 6, the pre-buried T-shaped sleeve 5 in the duct piece has a large limiting end plate and an external coarse thread structure, so that the bonding anchoring force between the sleeve and concrete can be increased to prevent separation, and the two ends of the pre-buried sleeve 6 are not plugged and are provided with internal straight thread structures. Two rows of T-shaped sleeves 5 can be longitudinally arranged along the tunnel, 57 sleeves are arranged in each row along the annular direction, the pre-embedded quantity can be determined according to the joint connection requirement, and the installation of the air duct structure is guaranteed.

As shown in fig. 7, in order to prevent the joint bolt from loosening or falling off under the action of the vibration load of the long-term train, a double anti-loosening nut 17 matched with the joint bolt can be arranged at the joint, a fastening steel backing plate 18 can be additionally arranged between the double anti-loosening nut 17 and the prefabricated part so as to ensure that the connection is more reliable, and tooth grooves 15 can also be arranged on the surfaces of the fastening steel backing plate 18 and the structural part contacted with the fastening steel backing plate 18.

As shown in FIG. 8, the longitudinal connecting plate 13 is made of Q355B steel plate, and has an optimized size design with the length of 750mm, the width of 80mm and the thickness of 10 mm. During installation and construction, the connecting bolts 7 are screwed in and the anti-loosening double nuts 17 are used for fastening the longitudinal connecting plates 13 on two sides of the vertical arm 9, and meanwhile, the whole body is formed by means of tooth groove meshing, so that the stress stability of the joint is improved. .

As shown in fig. 9, the horizontal mat 14 is made of Q355B steel plate and has a thickness of 10mm as an optimized size design. The design of the horizontal base plate 14 can increase the contact area between the prefabricated air duct plate and the steel bracket connecting piece, avoid the stress concentration damage at the connecting part and improve the reliability of the joint.

FIGS. 10-14 are schematic views showing the partial or complete assembly of the air duct structure of the present invention. The air duct structure is characterized in that a top pi-shaped connecting piece 3 is installed firstly during construction, a prefabricated vertical partition wall 2 is inserted vertically, bolts are screwed up and fixed after accurate positioning, a steel bracket connecting piece 4 is installed, a prefabricated air duct plate 1 is lifted to an installation height and is longitudinally pushed into along a tunnel, and all joint bolts are sequentially connected after adjustment and positioning to realize integral assembly of the structure.

The invention provides a full-assembly type rail top air duct structure aiming at the unfavorable conditions that a conventional cast-in-place mode is adopted for arranging the rail top air duct structure in a shield tunnel, steel bars need to be drilled and embedded, and the structure is damaged, wherein sleeves (5 and 6) are embedded in duct pieces and prefabricated parts through prefabricated concrete components and assembly type connecting pieces, and then the duct pieces and the prefabricated parts are assembled in a bolt connection mode. All parts of the assembled rail top air duct structure are prefabricated in a factory and produced, and are transported to a site for assembly, so that the assembly is convenient and fast to install, the construction speed can be increased, the construction period can be shortened, the material strength is high, the durability is good, and the maintenance and the replacement are convenient in the operation stage.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.