Construction method for lightning protection and grounding system of top-down inverse construction structure of an integrated transportation hub

Abstract

The present application discloses a construction method for a lightning protection and grounding system of a top-down inverse construction structure of an integrated transportation hub, which relates to the technical field of building lightning protection construction. A construction method for a lightning protection and grounding system of a top-down inverse construction structure of an integrated transportation hub includes, during the structural construction, welding and connecting the uplift piles, steel pipe columns and structural columns to form a pile-column lightning protection and grounding body; arranging a dissipation device on the walls on both sides of the subway line, and the stray current generated during subway operation is dissipated through the dissipation device and guided to the ground, and the lead-down point of the dissipation device is directly and separately welded and connected to the pile-column lightning protection and grounding body; during the construction of the inverse-order layer, anti-side terminals are reserved on both sides of the railway traffic line, and the anti-side terminals are welded and connected to the pile-column lightning protection and grounding body; connecting the lead-down point of the sequential-layer grounding grid to the connection point of the inverse-construction layer grounding grid, so that the upper and lower grounding grids form a path; the present application has the effect of improving the stability of the lightning protection and grounding system of a building project constructed by the top-down inverse construction method.

Description

Technical Field

[0001] The present application relates to the technical field of building lightning protection construction, and particularly to a construction method for a lightning protection and grounding system of a top-down excavation and reverse construction structure of an integrated transportation hub. Background Art

[0002] As shown in the attached Figure 1 , an integrated transportation hub project has a total of three underground floors, which are B3, B2, and B1 floors from the bottommost to the topmost. There is a railway line on the north side of the project and high-rise residential buildings on the south side. To reduce the impact of the construction process on surrounding facilities, the building structure is constructed using the top-down excavation and reverse construction method. Among them, the B3 floor is a junction hub for three railways, and there are also equipment rooms such as an energy station and a substation on the same floor; the B2 floor is a transfer station for the intersection of two subway lines, and there are also other equipment rooms such as an energy station on the same floor; the B1 floor is equipped with a parking lot for vehicle and pedestrian transfer, and there are also equipment rooms such as a substation and a distribution room on the same floor.

[0003] During the top-down excavation and reverse construction process, the B2 floor is constructed in sequence, and the B3 floor is constructed in reverse order. First, the anti-pull pile 1 is constructed, and the anti-pull pile 1 is located between the rock layer and the raft slab of the B3 floor; then, steel pipe columns 2 are driven between the B3 floor slab and the B2 floor slab as vertical support members. In addition to the steel pipe columns 2 as vertical support members in the B2 and B3 floors, concrete structural columns 3 are also constructed as vertical support members, and the B1 floor uses the concrete structural columns 3 as vertical support members. After the pile foundation and the steel pipe columns 2 are constructed, the earthwork is excavated to the elevation of the B2 floor slab, and the B2 floor slab, the B2 floor concrete structural column 3, and the beam-column of the B2 floor slab are constructed; after the B2 floor is constructed, the earthwork of the B3 floor is excavated downward, and the B3 floor concrete structural column 3 and the raft slab are constructed; after the B3 floor is constructed, the B1 floor concrete structural column 3 and the structural roof slab are constructed. The construction of the lightning protection and grounding system is interspersed throughout the entire construction process of the building structure.

[0004] During the top-down excavation and reverse construction process, the construction process is extremely complex; and for integrated hub projects, especially the grounding requirements for subway lines and train lines are of high quality, and the relevant lightning protection and grounding construction methods and processes applied to the top-down excavation and reverse construction method integrated transportation hub project cannot achieve a good lightning protection and grounding effect. Summary of the Invention

[0005] In order to improve the stability of the lightning protection and grounding system of a building project constructed using the top-down excavation and reverse construction method, the present application provides a construction method for a lightning protection and grounding system of a top-down excavation and reverse construction structure of an integrated transportation hub.

[0006] The present application provides a construction method for a lightning protection and grounding system of a top-down excavation and reverse construction structure of an integrated transportation hub, adopting the following technical solutions:

[0007] A construction method for the lightning protection and grounding system of the top-down inverse construction structure of an integrated transportation hub. During the structural construction, the coaxial uplift piles, steel pipe columns, and structural columns are welded and connected to form a pile-column lightning protection and grounding body.

[0008] During the construction of the sequential layer, the horizontal and vertical beam steel bars of the B2 floor slab are welded and connected through round steel at the set welding points to form a floor slab lightning protection and grounding body; the horizontal and vertical beam steel bars of the B2 floor slab are welded and connected through round steel at the set welding points to form a floor slab lightning protection and grounding body, and lead-down points are respectively reserved for welding and connecting with the structural columns or steel pipe columns of the adjacent layer.

[0009] Dissipating devices are arranged on the walls on both sides of the subway line on the B2 floor. The stray current generated during subway operation is dissipated through the dissipating devices and led to the ground. The lead-down points of the dissipating devices are directly and separately welded and connected to the pile-column lightning protection and grounding body.

[0010] During the construction of the reverse layer, lightning protection side terminals are reserved at the railway traffic line on the B3 floor, and the lightning protection side terminals are welded and connected to the pile-column lightning protection and grounding body.

[0011] Connect the lead-down points of the sequential layer with the lightning protection and grounding connection points of the reverse construction layer, so that a path is formed between the lightning protection and grounding structures of the sequential layer and the reverse construction layer; connect the floor slab lightning protection and grounding body and the floor slab lightning protection and grounding body to the pile-column lightning protection and grounding body to form a closed main lightning protection and grounding system.

[0012] Flat steel is extended along the axial direction on the outer wall of the structural column in the high-voltage equipment site of the sequential layer. After connecting the neutral points of each layer, it is embedded to the reverse layer and connected to the flat steel during the lightning protection and grounding construction of the reverse layer and introduced into the ground.

[0013] Optionally, the floor slab lightning protection and grounding body and the floor slab lightning protection and grounding body are constructed in several flow segments. The cross-connection points of each flow segment are connected in series by welding to form an integral body and are led to the ground through several pile-column lightning protection and grounding bodies.

[0014] By adopting the above technical solution, the lightning protection and grounding bodies of multiple flow segments are connected in series by welding, and the floor slab lightning protection and grounding body and the floor slab lightning protection and grounding body of the entire project are connected as a whole, making the lightning protection and grounding effect and conductivity of the entire project better.

[0015] Optionally, the uplift pile includes a steel pipe pile inside and a concrete pile layer arranged outside the steel pipe pile. A pile reinforcement cage is arranged in the concrete pile layer. During the lightning protection and grounding construction, the outer wall of the steel pipe pile is welded and connected to the surrounding pile reinforcement cage.

[0016] By adopting the above technical solution, the pile reinforcement cage is welded and connected to the steel pipe pile, making the conductivity of the pile-column lightning protection and grounding body better and more stable.

[0017] Optionally, during the construction of the lightning protection grounding welding for the raft slab of B3 layer, the double-layer steel bar mesh of the raft slab is respectively welded and connected to the lightning protection grounding body of the pile column;

[0018] Weld the lower-layer steel bar mesh of the raft slab to the vertical steel bars of the pile reinforcement cage, and weld and connect the upper-layer steel bar mesh of the raft slab to the vertical steel bars at the four corners of the structural column; at the same time, weld and connect the vertical steel bars in the structural column of B3 layer to the steel bars on the side wall of the foundation pit.

[0019] By adopting the above technical solution, the lightning protection grounding body of the pile column is welded and connected to the raft slab of B3 layer, so that the lightning protection grounding system of the whole project can be better welded and connected to the lightning protection grounding body of the pile column. The current is led underground through the lightning protection grounding body of the pile column, making the lightning protection and conduction effect of the whole project better.

[0020] Optionally, during the welding of the subway line disbanding device in B2 layer, set the ring-shaped stirrups parallel to the cross-section of the subway line as the first connecting steel bars, and set the steel bars in the extending direction of the subway line as the second connecting steel bars. Select multiple first connecting steel bars and multiple second connecting steel bars to be welded and connected at intervals. The multiple second connecting steel bars are welded and connected to the vertical steel bars at the four corners of the structural column, and the vertical steel bars of the structural column are connected to the lightning protection grounding body of the top plate to form a closed loop.

[0021] By adopting the above technical solution, select the steel bars in the surrounding wall of the subway as the conductors of the disbanding device. Through the welding and connection of the first connecting steel bars, the second connecting steel bars and the longitudinal column bars, the conductive system around the subway line forms a closed loop, which can better dissipate the stray current and ensure the normal operation of the subway line.

[0022] Optionally, during the construction of the sequential layer, set a wing ring at the top of the steel pipe column, and weld and connect the four diagonal steel bars in the structural column of B1 layer to the wing ring.

[0023] By adopting the above technical solution, weld and fix the four diagonal steel bars in the structural column to the wing ring at the top of the steel pipe column to enhance the effective connection between the structural column and the steel pipe, making the lightning protection and conduction effect of the lightning protection grounding body of the pile column better.

[0024] Optionally, for the neutral point grounding at the equipment room, use galvanized flat steel to lay along the outside of the structural column to the structural floor of B2 layer, and weld and connect the galvanized flat steel to the lightning protection grounding body of the pile column to form a neutral point grounding body; the neutral point grounding body is isolated from the main body lightning protection grounding body system, and the two form a separate loop.

[0025] By adopting the above technical solution, the equipment grounding of each equipment room can be reserved in advance from the structural column through the flat steel, which is convenient for subsequent installation of equipment in the equipment room; and separating the welding of the neutral point of the equipment room from the overall lightning protection grounding body of the structure reduces the interference between the two, and the construction process is simpler and it is not easy to have construction errors.

[0026] Optionally, when performing lightning protection welding construction at the railway track of the B3 layer, anti-side terminals are reserved. The anti-side terminals are welded and connected to the pile column lightning protection grounding body, and the anti-side terminals are connected to the ground as conductors.

[0027] Grounding steel plates are set on the structural columns on both sides of the railway track, and the grounding steel plates are welded and connected to the lead-down points of the structural columns as grounding test terminals.

[0028] By adopting the above technical solutions, setting the anti-side terminals ensures the conductive effect around the subway line, and welding and connecting the anti-side terminals to the pile column lightning protection grounding body makes the conductive effect better; setting the grounding steel plates on the structural columns around the subway line makes it more convenient to perform lightning protection grounding for equipment or overhaul the lightning protection grounding system near the subway line during the subsequent use of the railway line.

[0029] Optionally, the vertical steel bars at the four corners of the structural column are uniformly used as the lead-down points during welding, and two steel bars on the outside of the structural beam are uniformly selected as conductors for welding between the structural beams.

[0030] By adopting the above technical solutions, the effective connection between conductors is enhanced, the situation of affecting the construction effect due to inadequate connection is reduced, and the phenomenon of forgetting or inadequate connection in reverse-order layer construction due to too long time is reduced.

[0031] Optionally, all lead-down points and cross-connection points of the flow segments are specially marked.

[0032] By adopting the above technical solutions, the situation of missed connection or missed welding during the welding and connection of the grounding grids of each flow segment or each layer is reduced, and the construction personnel can better identify the lead-down points and cross-connection points, which is convenient for the construction personnel to construct and reduces the construction error.

[0033] In summary, the present application includes at least one of the following beneficial effects:

[0034] 1. The lightning protection and grounding construction method of the present application is applicable to various cut-and-cover reverse construction sites, with a small welding area, a controllable welding range, a simplified welding process, which can meet the requirements of the lightning protection and grounding welding resistance value, reduces the occurrence of repeated welding in grounding welding, and ensures the construction progress.

[0035] 2. The lightning protection and grounding welding follows the structural construction progress, so that the lightning protection and grounding construction has less influence on the reverse-order layer construction, and the reverse-order layer support structure is used as a conductor without the need to separately set a conductor.

[0036] 3. Using the pile column lightning protection grounding body as the grounding wire greatly improves the stability of the grounding system, and the lightning protection and grounding system formed by this construction method is more stable than the grounding system of ordinary public buildings.

[0037] 4. Separate the stray current of the subway line and the lightning protection grounding and reserve conductors separately to reduce the interference between the two. Description of the Drawings

[0038] Figure 1 is a schematic diagram of the engineering structure of an embodiment of the present application;

[0039] Figure 2 is a schematic diagram of the pile-column lightning protection grounding body of an embodiment of the present application;

[0040] Figure 3 is a schematic diagram of the cross-connection point of an embodiment of the present application;

[0041] Figure 4 is a schematic diagram of the selection point of the vertical steel bars of the structural column of an embodiment of the present application;

[0042] Figure 5 is a schematic diagram of the disassembly device of an embodiment of the present application;

[0043] Figure 6 is a schematic diagram of the down-lead point of an embodiment of the present application;

[0044] Figure 7 is a schematic diagram of the anti-pull pile structure of an embodiment of the present application;

[0045] Figure 8 is a schematic diagram of the welded connection of the pile column of an embodiment of the present application;

[0046] Figure 9 is a schematic diagram of the lightning protection grounding around the subway line of an embodiment of the present application;

[0047] Figure 10 is a schematic diagram of the welded connection between the structural column and the steel pipe column of an embodiment of the present application;

[0048] Figure 11 is a schematic diagram of the neutral point grounding body of an embodiment of the present application.

[0049] Description of the reference numerals: 1, anti-pull pile; 2, steel pipe column; 3, structural column; 4, bottom plate lightning protection grounding body; 5, cross-connection point; 6, disassembly device; 7, first connecting steel bar; 8, second connecting steel bar; 9, top plate lightning protection grounding body; 10, steel pipe pile; 11, concrete pile layer; 111, pile reinforcement cage; 12, anti-side terminal; 13, grounding test terminal; 14, wing ring; 15, neutral point grounding body; 151, neutral point grounding flat steel; 16, pile-column lightning protection grounding body. Detailed Description of the Embodiment

[0050] The following is a further detailed description of the present application in conjunction with the attached Figures 1 - 11 drawings.

[0051] A construction method for the lightning protection and grounding system of the top-down inverse construction structure of an integrated transportation hub disclosed in the embodiments of the present application. The construction of the lightning protection and grounding system for the integrated transportation hub project is inserted into the construction of the structural layer throughout the whole cycle. The construction plane of the whole project is divided into multiple construction sections, and the structures of each construction section can be constructed simultaneously to ensure the construction progress. When constructing the lightning protection and grounding system, after the lightning protection and grounding of multiple construction sections are welded and constructed separately, the welding connection of the lightning protection and grounding of each construction section is carried out. According to the characteristics of the top-down inverse construction method, the B1 and B2 floors are constructed as sequential floors, and the B3 floor is constructed as an inverse floor.

[0052] The overall construction idea is: referring to Figure 1 and Figure 2 , connect the down-lead points of the lightning protection grounding network of the sequential floor with the connection points of the lightning protection grounding network of the inverse construction floor, so that the lightning protection grounding network of the sequential floor and the lightning protection grounding network of the inverse construction floor form a path; connect the roof lightning protection grounding body 9 and the floor lightning protection grounding body 4 to the pile column lightning protection grounding body 16 to form a closed main lightning protection and grounding system.

[0053] Referring to Figure 1 and Figure 2 , before the earth excavation, construct the uplift piles 1 and steel pipe columns 2 in the area where the earth is to be excavated. After the construction of the uplift piles 1 and steel pipe columns 2 is completed, carry out the earth excavation construction. The first earth excavation excavates the earth to the elevation of the B2 floor slab, and then carry out the construction of the B2 floor slab and the structural beams on the elevation of the B2 floor slab. During the construction process, according to the construction drawings, connect the transverse and longitudinal steel bars at the lightning protection grounding points designed for the B2 floor slab and the structural beams by welding with round steel with a diameter of Φ12, and connect the steel bar mesh of the entire B2 floor slab by welding to form the floor lightning protection grounding body 4. Referring to Figure 2 and Figure 3 , since the construction process is divided into several construction sections for simultaneous construction, after each construction section of the B2 floor slab is constructed, leave a cross-connection point 5 at the connection between each construction section and mark the cross-connection point 5. The marking is carried out using a paint color different from that used in building construction to mark the cross-connection point 5, so as to reduce the error in the selection of the cross-connection point 5 steel bars when the cross-connection points 5 between each construction section are welded and connected, ensure the welding connection between each construction section, and make the entire B2 floor slab form a connected floor lightning protection grounding body 4.

[0054] Referring to Figure 2 , after the construction of the B2 floor slab structure is completed, select some steel pipe columns 2 and structural columns 3 as conductors (the descriptions of the steel pipe columns 2 and structural columns 3 hereinafter all refer to the steel pipe columns 2 and structural columns 3 used as conductors), and connect the vertical steel bars of the structural column 3 or the side walls of the steel pipe columns 2 to the floor lightning protection grounding body 4 by welding with round steel with a diameter of Φ12. To ensure the effective connection between the conductors and reduce the situation that the construction effect is affected due to insufficient connection, referring to Figure 4, when selecting the vertical steel bars of the structural column 3, the steel bars at the four corners of the structural column 3 are uniformly used as the lead-down points for welding, so as to reduce the phenomenon of forgetting due to too long time or the poor connection in the reverse-order layer construction. During the whole construction process, when welding between the transverse beam and the longitudinal beam, two steel bars on the outer side of the beam are also uniformly selected as conductors for welding.

[0055] Refer to Figure 2 and Figure 5 , when constructing the wall around the subway line on the B2 floor, since a large amount of stray current will be generated during the operation of the subway, it is necessary to dissipate the stray current generated around the subway line. A dissipation device 6 is set in the wall around the subway line. The construction of the dissipation device 6 is mainly carried out by effectively welding the wall steel bars with the steel bars of the structural column 3 on the B2 floor, and leading the reserved points of the lead-down wires of the stray current to the raft slab and welding and connecting them with the steel pipe column 2 and the anti-pull pile 1 to be introduced into the ground, forming a separate stray current loop conductor. During the specific construction process, the circular stirrups of the wall on the peripheral side of the subway line are used as the first connecting steel bars 7, and the steel bars in the extending direction of the subway line are used as the second connecting steel bars 8. When welding the dissipation device 6, three second connecting steel bars 8 are selected as conductors to be welded and connected with the vertical steel bars of the structural column 3 around the subway line. When selecting the second connecting steel bars 8, the height of the second connecting steel bars 8 from the subway track should be greater than 1.8 meters; several first connecting steel bars 7 are selected at intervals to weld and connect the first connecting steel bars 7 with the three second connecting steel bars 8. When selecting the first connecting steel bars 7, one first connecting steel bar 7 is selected every 5 meters along the subway track line. The second connecting steel bars 8 are welded and connected with the lightning protection grounding body 4 of the B2 floor slab, so that the whole subway line forms a closed space, and thus the stray current generated during the operation of the subway can be effectively dissipated.

[0056] When welding the stray current of the subway line, the stray current conductor is separated from the lightning protection grounding conductor of the whole structure, so as to avoid sharing the vertical steel bar of the same structural column 3 as the conductor, and the conductor of the stray current is marked with colored paint different from other lead-down wires when introduced into the reverse-order layer. By directly introducing the stray current on the peripheral side of the subway line into the ground separately, the interference with the lightning protection grounding system of the whole structure of this project is reduced.

[0057] Refer to Figure 1 and Figure 2 , after the construction of the structural column 3 on the B2 floor is completed, the construction of the B2 floor roof structure is carried out. The steel bars of the B2 floor roof are welded and connected by using a round steel with a diameter of Φ12 according to the welding points selected in the construction design drawing to form a roof lightning protection grounding body 9. Refer to Figure 6 The schematic diagram of the lead-down point for marking is shown as follows. When constructing the roof lightning protection grounding body 9, lead-down points are reserved under the B2 floor roof, and the lead-down points reserved by the structural column 3 on the B2 floor are welded and connected with the lead-down points reserved by the B2 floor roof.

[0058] After the construction of the top slab of B2 layer is completed, the earthwork excavation of B3 layer is carried out. After the earthwork of B3 layer is excavated to the elevation of the raft slab of B3 layer, the steel bar binding and concrete pouring construction of the raft slab of B3 layer are carried out. Refer to Figure 7 , in this project, the uplift pile 1 includes the steel pipe pile 10 inside and the concrete pile layer 11 arranged outside the steel pipe pile 10, and the pile reinforcement cage 111 is arranged in the concrete pile layer 11. Before the raft slab construction, the pile reinforcement cage 111 and the side wall of the steel pipe pile 10 are welded and connected by four Φ12 diagonal round steel bars, and the coaxial uplift pile 1, steel pipe column 2 and the structural column 3 in the subsequent construction steps are welded and connected to form the pile-column lightning protection grounding body 16 as shown in Figure 2 . Refer to Figure 8 , when binding the steel bars of the raft slab, the lower steel bar mesh of the raft slab is welded and connected to the pile reinforcement cage 111 by Φ12 round steel bars, and the upper steel bar mesh of the raft slab is welded and connected to the side wall of the steel pipe column 2 by Φ12 round steel bars.

[0059] Refer to Figure 2 , the horizontal and vertical steel bars of the raft slab steel bar mesh layer are welded and connected by Φ12 round steel bars and are welded and connected to the pile-column lightning protection grounding body 16. After the pouring construction of the raft slab of B3 layer is completed, the construction of the structural column 3 of B3 layer is carried out. When constructing the structural column 3 of B3 layer, the vertical steel bars in the structural column 3 are welded and connected to the steel bars on the side wall of the foundation pit to achieve a better lightning protection and grounding effect for the whole project.

[0060] Refer to Figure 9 , during the lightning protection and grounding construction of the railway rail transit on B3 layer, anti-side terminals 12 are reserved on both sides of the railway track line. The anti-side terminals 12 are welded to the structural column 3 500 mm above the ground through φ12 round steel bars, or are welded to the steel pipe column 2 500 mm above the ground through a 50 mm * 5 mm galvanized flat steel bar (the example in Figure 9 is that the anti-side terminal is welded to the steel pipe column 500 mm above the ground through the galvanized flat steel bar), and the anti-side terminals 12 are connected to the ground as conductors during the railway track construction.

[0061] Refer to Figure 9 , using the structural column 3 or the steel pipe column 2 on both sides of the railway line as the grounding downlead point, a grounding steel plate is set at a certain distance from the completed surface of the B3 layer floor structure of the structural column 3. The grounding steel plate is welded to the steel reinforcement cage of the structural column 3 and the grounding steel plate is welded and connected to the downlead point as the grounding test terminal 13. The top of the longitudinal steel bars in the structural column 3 of B3 layer is welded and connected to the lightning protection and grounding body 4 of the B2 layer floor, and the bottom of the longitudinal steel bars in the structural column 3 of B3 layer is welded and connected to the steel bars of the raft slab of B3 layer. At the same time, the grounding test terminal 13 set on the structural column 3 of B3 layer is welded and connected to the pile-column lightning protection grounding body 16 through Φ12 round steel bars.

[0062] Refer to Figure 1 and Figure 10, after completing the construction of the B3 floor structure and lightning protection and grounding, and connecting the lightning protection and grounding system of the B3 floor with that of the B2 floor up and down, carry out the construction of the structural column 3 on the B1 floor. There is a wing ring 14 at the top of the steel pipe column 2. Weld and connect the steel bars of the structural column 3 on the B1 floor with the wing ring 14, so as to connect the structural column 3 on the B1 floor to the pile column lightning protection and grounding body 16. After the construction of the structural column 3 on the B1 floor is completed, carry out the construction of the B1 floor roof structure. When carrying out the construction of the B1 floor roof structure, connect the steel bar mesh layer in the roof structure with the longitudinal steel bars of the structural column 3.

[0063] Refer to Figure 2 and Figure 11 , when carrying out the lightning protection and grounding construction of equipment rooms such as substations and switchgear stations on each sequential floor, use a 100*10 galvanized flat steel along the outside of the structural column 3 as the neutral point grounding flat steel 151. After welding and connecting each neutral point, embed it into the reverse-order floor. When carrying out the lightning protection and grounding construction of the reverse-order floor, connect the pile column lightning protection and grounding body 16 with the neutral point grounding flat steel 151 and introduce it into the ground to form an effective connection. Take the lightning protection and grounding path with the neutral points welded and connected as the neutral point grounding body 15. During the entire construction process of the neutral point grounding body 15, the neutral point grounding body 15 is isolated from the lightning protection and grounding body of the entire structure, and the two form separate circuits.

[0064] In the welding of the neutral point of a single switchgear station, set a separate neutral point lead-down point to reduce the possibility of forming a circulating current between the neutral points, so as to ensure the safety, reliability, economy and practicability of the neutral point grounding body and the lightning protection and grounding system of the entire structure.

[0065] The above are all the preferred embodiments of this application. The protection scope of this application is not limited by this. Therefore: All equivalent changes made according to the structure, shape and principle of this application should be covered within the protection scope of this application.

Claims

1. A construction method for the lightning protection and grounding system of a top-down excavation and reverse construction structure of an integrated transportation hub, which uses the top-down excavation and reverse construction method for the construction of structural layers. The sequential layers include the B1 layer and the B2 layer, and the reverse sequential layer includes the B3 layer. A number of structural columns (3) are provided in each of the B1, B2, and B3 layers. A number of uplift piles (1) are provided below the raft slab of the B3 layer. A number of steel pipe columns (2) are provided in the B2 and B3 layers, characterized in that: During the structural construction, the coaxial tension piles (1), steel pipe columns (2) and structural columns (3) are welded and connected to form a pile-column lightning protection grounding body (16). During the sequential floor construction, the horizontal and vertical beam steel bars on the top slab of B2 floor are welded and connected through round steel at the set welding points to form a top slab lightning protection grounding body (9); the horizontal and vertical beam steel bars on the bottom slab of B2 floor are welded and connected through round steel at the set welding points to form a bottom slab lightning protection grounding body (4), and lead-down points are respectively reserved for welding and connecting with the structural columns (3) or steel pipe columns (2) of the adjacent floors. Dissipating devices (6) are arranged on the walls on both sides of the subway line on B2 floor. The stray current generated during subway operation is dissipated through the dissipating devices (6) and led to the ground. The lead-down points of the dissipating devices (6) are directly and separately welded and connected to the pile-column lightning protection grounding body (16). During the reverse sequential floor construction, lightning protection side terminals (12) are reserved on the railway traffic line on B3 floor, and the lightning protection side terminals (12) are welded and connected to the pile-column lightning protection grounding body (16). Connect the lead-down points of the sequential floors with the lightning protection grounding connection points of the reverse construction floors, so as to form a path between the lightning protection grounding structures of the sequential floors and the reverse construction floors; connect the top slab lightning protection grounding body (9) and the bottom slab lightning protection grounding body (4) to the pile-column lightning protection grounding body (16) respectively to form a closed main body lightning protection grounding system. Flat steel is arranged along the axial direction on the outer wall of the structural column (3) in the high-voltage equipment site of the sequential floors. The flat steel connects the neutral points of each floor and is embedded to the reverse sequential floor, and is connected to the flat steel during the lightning protection grounding construction of the reverse sequential floor and led into the ground. The neutral point grounding at the equipment room is carried out by laying galvanized flat steel along the outside of the structural column (3) to the structural floor of B2 floor, and the galvanized flat steel is welded and connected to the pile-column lightning protection grounding body (16) to form a neutral point grounding body (15); the neutral point grounding body (15) is isolated from the main body lightning protection grounding body system, and the two form a separate loop.

2. The construction method of the lightning protection and grounding system for the top-down and reverse construction structure of an integrated transportation hub according to claim 1, characterized in that: The top slab lightning protection grounding body (9) and the bottom slab lightning protection grounding body (4) are constructed in several flow segments. The cross-connection points (5) of each flow segment are connected in series by welding to form an integral body, and are led to the ground through several pile-column lightning protection grounding bodies (16).

3. The construction method of the lightning protection and grounding system for the top-down inverse construction structure of an integrated transportation hub according to claim 1, characterized in that: The tension pile (1) includes an internal steel pipe pile (10) and a concrete pile layer (11) arranged outside the steel pipe pile (10). A pile reinforcement cage (111) is arranged in the concrete pile layer (11). During the lightning protection grounding construction, the outer wall of the steel pipe pile (10) is welded and connected to the surrounding pile reinforcement cage (111).

4. A construction method for a lightning protection and grounding system of a top-down inverse construction structure of an integrated transportation hub according to claim 3, characterized in that: During the lightning protection grounding welding construction of the raft slab on B3 floor, the double-layer steel bar mesh of the raft slab is respectively welded and connected to the pile-column lightning protection grounding body (16); the lower-layer steel bar mesh of the raft slab is welded to the vertical steel bars of the pile reinforcement cage (111), and the upper-layer steel bar mesh of the raft slab is welded and connected to the vertical steel bars at the four corners of the structural column (3); at the same time, the vertical steel bars in the structural column (3) on B3 floor are welded and connected to the steel bars on the side wall of the foundation pit.

5. The construction method of the lightning protection and grounding system for the top-down and reverse construction structure of an integrated transportation hub according to claim 1, characterized in that: When welding the B2-layer subway line disassembly device (6), the annular stirrups parallel to the cross-section of the subway line are set as the first connecting steel bars (7), and the steel bars in the extending direction of the subway line are set as the second connecting steel bars (8). Multiple first connecting steel bars (7) and multiple second connecting steel bars (8) are selected at intervals and welded and connected. Multiple said second connecting steel bars (8) are welded and connected to the vertical steel bars at the four corners of the structural column (3). The vertical steel bars of the structural column (3) are connected to the roof lightning protection grounding body (9) to form a closed loop.

6. The construction method of the lightning protection and grounding system for the top-down inverse construction structure of an integrated transportation hub according to claim 5, characterized in that: During the construction of the sequential layer, a wing ring (14) is set at the top of the steel pipe column (2), and the four diagonal steel bars in the B1-layer structural column (3) are welded and connected to the wing ring (14).

7. A construction method for the lightning protection and grounding system of the top-down and reverse construction structure of an integrated transportation hub according to claim 1, characterized in that: When carrying out the lightning protection welding construction at the B3-layer railway track, a side protection terminal (12) is reserved. The side protection terminal (12) is welded and connected to the pile column lightning protection grounding body (16), and the side protection terminal (12) is connected to the ground as a conductor; Grounding steel plates are set on the structural columns (3) on both sides of the railway track, and the grounding steel plates are welded and connected to the lead-down points of the structural columns (3) as grounding test terminals (13).

8. The construction method of the lightning protection and grounding system for the top-down inverse construction structure of an integrated transportation hub according to claim 1, wherein: The vertical steel bars at the four corners of the structural column (3) are uniformly selected as the lead-down points, and the welding between the structural beams uniformly selects two steel bars outside the structural beams as conductors for welding.

9. The construction method of the lightning protection and grounding system for the top-down inverse construction structure of an integrated transportation hub according to claim 1, characterized in that: During the construction, all the lead-down points and the cross-connection points of the flow sections (5) are specially marked.

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