Construction method for connecting section of subway station ventilation pavilion and station main body structure

Abstract

The invention relates to the field of foundation pit construction in civil engineering, and discloses a subway station ventilation pavilion and station main body structure connecting section construction method which comprises the following steps that firstly, station foundation pit fender posts and a station structure are constructed, a plurality of upturning beams are evenly arranged on a station top plate over two rows of station frame columns on the side, close to the ventilation pavilion structure, of a communication area of the station structure and the ventilation pavilion structure, and foundation bolts are embedded in the two ends of the upturning beams and located over the station frame columns. 2, constructing a ventilation pavilion foundation pit fender post, and performing layered excavation to the elevation of a first concrete support; the first concrete support and the second steel support of the ventilation pavilion foundation pit between the ventilation pavilion structure and the station structure communicating area do not act on the station enclosure structure, so that the station enclosure structure can be gradually cut and removed according to the ventilation pavilion foundation pit excavation step, the number of post-cast strips and joints are reduced, the construction quality of mutual connection is improved, and the construction cost is reduced. The risk of water seepage at the joint of the post-cast strip is reduced, and the construction period is shortened.

Description

Technical Field

[0001] This invention relates to the field of foundation pit construction in civil engineering, and more particularly to a construction method for the connection section between the ventilation shaft and the main structure of a subway station in a ventilation shaft foundation pit project connected to an existing subway station. Background Technology

[0002] In the construction of urban subway stations, the main structure of the station is often constructed first, followed by the ventilation shaft structure. After the ventilation shaft foundation pit is excavated to the bottom and the ventilation shaft structure is poured, the retaining structure (including the upper capping beam and retaining wall) at the junction with the main structure needs to be removed, and the post-pouring strip needs to be poured to form a connected integral structure.

[0003] Traditional methods for connecting the ventilation shaft structure to the main station structure have the following limitations: (1) During the construction of the ventilation shaft's auxiliary foundation pit, the horizontal support of the foundation pit was erected on the main structure's foundation pit retaining structure. This resulted in the main structure's foundation pit retaining structure being removed only after the ventilation shaft structure was capped. Consequently, there were post-pouring strips between the station's main structure and the ventilation shaft's bottom and top slabs, which were constructed at different stages, were divided into smaller sections, and had more joints. These strips became the main source of water leakage in the later stages.

[0004] (2) The demolition of the enclosure structure at the junction of the ventilation shaft structure and the main structure requires alternating cutting and hoisting in sections and segments. The construction work surface is narrow, the construction period is long, which increases the construction cost and the construction efficiency is low.

[0005] Therefore, it urgently needs to be addressed. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a construction method for the connection section between the ventilation shaft and the main structure of a subway station. The first concrete support and the second steel support of the ventilation shaft foundation pit between the ventilation shaft structure and the station structure do not act on the station retaining structure. As a result, the station retaining structure can be gradually cut and removed according to the excavation steps of the ventilation shaft foundation pit, which reduces the number of post-pouring strips and joints, improves the construction quality of the interconnection, and reduces the risk of water seepage at the connection of the post-pouring strips.

[0007] To achieve the aforementioned objective, the technical solution of the present invention is implemented as follows: A construction method for the connection section between a subway station ventilation shaft and the main structure of the station, comprising the following steps: Step 1: Construct the station foundation pit retaining piles and station structure, as detailed below: The station foundation pit retaining piles, capping beams, and retaining walls are constructed sequentially; the station foundation pit is excavated in alternating layers and horizontal supports are constructed until the design elevation is reached; the station structure is constructed in stages and the supports are replaced until the station structure construction is completed; during the construction of the station structure, multiple upturned beams are evenly installed on the station roof slab directly above the two rows of station frame columns on the side closest to the ventilation shaft structure in the area where the station structure and ventilation shaft structure are connected. Anchor bolts are pre-embedded at both ends of the upturned beams, and the anchor bolts are located directly above the station frame columns. Step Two: Construct retaining piles for the wind tunnel foundation pit and excavate in layers to the elevation of the first concrete support, as detailed below: Construct the retaining piles and top beams of the ventilation shaft foundation pit, and the lattice columns. Excavate the ventilation shaft foundation pit in layers to the bottom elevation of the first concrete support. Cut and remove the retaining wall, top beam, and station retaining piles between the station structure and the ventilation shaft structure to the soil excavation surface elevation. Install triangular steel supports on the upturned beams of the station roof based on the anchor bolts. Step 3: Construct the first layer of concrete support for the wind tunnel foundation pit. Step 4: Excavate the ventilation shaft foundation pit in layers until the elevation of the second steel support is reached, and then construct the second steel support. Step 5: Excavate the ventilation shaft foundation pit in layers to the design elevation, and simultaneously cut and remove the station retaining piles between the station structure and the ventilation shaft structure to the soil excavation surface elevation; Step Six: Construct the pavilion structure, as detailed below: The ventilation shaft base slab and waterproof layer are constructed, followed by the construction of the ventilation shaft base slab, side walls, and roof slab structure in sequence; ventilation shaft frame columns are set in the area where the station structure and ventilation shaft structure are connected; the ventilation shaft base slab and the station middle slab are connected by rebar and concrete pouring to form an integral whole. Step 7: Construct the post-pouring strip for the roof slab of the wind pavilion structure, as detailed below: After the post-construction settlement of the ventilation shaft structure meets the relevant requirements, the post-cast strip between the top slab of the ventilation shaft structure and the top slab of the station will be constructed. Step 8: Remove the horizontal supports of the ventilation shaft foundation pit; Step Nine: Waterproofing of the ventilation shaft roof and backfilling of the foundation pit, as detailed below: According to relevant specifications, the roof slab of the wind tunnel structure is waterproofed, and then the foundation pit is backfilled in layers according to relevant requirements (or the roadbed and pavement of the upper part are constructed) until the project is completed.

[0008] Preferably, in step two, the process of constructing the first concrete support for the ventilation shaft foundation pit includes: setting up formwork, binding reinforcing bars, and pouring concrete at the upper ends of each triangular steel support to form a new cap beam; the end of the first concrete support at the connection between the ventilation shaft structure and the station structure is connected to the new cap beam; and several horizontal bracings are evenly arranged between the new cap beam 23 and the cap beam of the station retaining piles on the side away from the ventilation shaft foundation pit.

[0009] Preferably, in step four, the ventilation shaft foundation pit is excavated in layers to the elevation of the second steel support. The process of constructing the second steel support includes: excavating the ventilation shaft foundation pit in layers to the bottom elevation of the second steel support; cutting and removing the station retaining piles between the station structure and the ventilation shaft structure to the elevation of the soil excavation surface; constructing the second steel support, with the end of the second steel support near the existing station structure supported on the station side wall, and each steel support assembled and fixed between the adjacent station frame columns of the station structure based on the steel pipe fixing bracket.

[0010] Preferably, in step eight, the process of dismantling the horizontal support of the ventilation shaft foundation pit includes: dismantling the steel pipe fixing bracket, removing the second steel support of the ventilation shaft foundation pit; cutting and removing the first concrete support and constructing a new cap beam, removing the horizontal support; and dismantling the triangular steel bracket.

[0011] Preferably, the triangular steel support is welded from a base plate, vertical ribs, and diagonal ribs. Bolt holes at both ends of the base plate are provided to match the anchor bolts at both ends of the upper beam. The vertical and diagonal ribs have a cross-shaped cross section. A flat support plate is provided at the upper end of the vertical rib. When the triangular steel support is assembled with the upper beam, the vertical ribs of the triangular steel support should be positioned on the side closest to the ventilation shaft.

[0012] Preferably, the horizontal bracing is made of steel pipe; the horizontal bracing is set on the extension line of the first concrete support at the connection between the ventilation shaft structure and the station structure.

[0013] Preferably, the steel pipe fixing bracket is welded from an upper wing plate, a web plate, and a lower wing plate. A semi-circular clamp is welded to one end of the steel pipe fixing bracket, and a rectangular clamp is welded to the other end. Connecting plates are provided at both ends of the semi-circular clamp, and at least one bolt hole is evenly distributed on the connecting plates. The inner diameter of the semi-circular clamp is equal to the outer diameter of the steel support. The semi-circular clamps on the two steel pipe fixing brackets can be assembled into a circle using bolts. Connecting plates are provided at both ends of the rectangular clamp, and at least one bolt hole is evenly distributed on the connecting plates. The rectangular clamps on the two steel pipe fixing brackets can be assembled into a circle using bolts and fixed to the station frame column.

[0014] Preferably, after the semi-circular clamps at one end of the two steel pipe fixing brackets are assembled with bolts to fix the steel support, the rectangular clamps at the other end of the two steel pipe fixing brackets can be respectively assembled with other rectangular clamps and fixed to the two station frame columns adjacent to the steel support.

[0015] Preferably, the end of the second steel support of the ventilation shaft foundation pit near the existing station structure is supported on the station side wall, and an end pad is provided between the end of the steel support and the station side wall; multiple bottom pads are evenly arranged above the station middle plate and placed below the steel support.

[0016] Preferably, multiple bottom pads are evenly arranged between the newly built cap beam and the station roof slab.

[0017] The beneficial effects of this invention are: (1) The first concrete support and the second steel support of the ventilation shaft foundation pit between the ventilation shaft structure and the station structure provided by the present invention do not act on the station retaining structure, so the station retaining structure can be gradually cut and removed according to the ventilation shaft foundation pit excavation steps. Compared with the traditional method, this setting makes the cutting and removal of the existing station retaining structure simple and convenient, provides a spacious construction space, improves construction safety, and shortens the construction period.

[0018] (2) During the construction of the ventilation shaft structure provided by the present invention, since the existing station retaining piles have been cut and removed, the ventilation shaft base plate and the station middle plate are directly connected to form an integral whole, and there is no need to set up a post-pouring strip. By reducing the setting of post-pouring strips, the construction quality of the interconnection is improved and the risk of water seepage at the subsequent connection is reduced.

[0019] (3) In the solution provided by the present invention, since the existing station retaining piles have been cut and removed, the post-pouring strip between the ventilation shaft structure top plate and the station top plate does not need to be divided into sections or blocks, and can be formed as a whole, which reduces the number of post-pouring strip joints, improves the construction quality of mutual connection, and reduces the risk of water seepage at the post-pouring strip connection.

[0020] (4) The solution provided by the present invention forms the first concrete support at the connection between the ventilation shaft structure and the station structure by means of the upward beam, triangular steel bracket, newly built crown beam, first concrete support, and horizontal continuous support. The force path is clear, the structure is simple, and the construction is convenient.

[0021] (5) In the solution provided by the present invention, the end of the second steel support of the ventilation shaft foundation pit is supported on the side wall of the station. The second steel support is assembled and fixed between the adjacent station frame columns based on the steel pipe fixed bracket. The force path is clear, the construction is simple, and the assembly and disassembly are convenient, providing a new idea for the design of ventilation shaft foundation pit. Attached Figure Description

[0022] Figure 1 Here is a flowchart of the main steps of the proposed construction method; Figure 2 This is a cross-sectional view of a traditional construction method. Figure 3 A three-dimensional schematic diagram of the proposed steel pipe fixing support. Figure 1 ; Figure 4 A three-dimensional schematic diagram of the proposed steel pipe fixing support. Figure 2 ; Figure 5 A three-dimensional schematic diagram of two steel pipe fixing supports assembled together based on a semi-circular clamp. Figure 6 A schematic diagram of two steel pipe fixed supports assembling together to form a circumferential steel support; Figure 7 A three-dimensional schematic diagram of two steel pipe fixing supports assembled with rectangular clamps; Figure 8 A schematic diagram of two steel pipe fixing supports assembling together around a station frame column based on rectangular clamps; Figure 9 This is a schematic diagram of the assembly of a steel pipe fixing bracket and a rectangular clamp; Figure 10 A schematic diagram of the assembly of a steel pipe fixing bracket and rectangular clamps encircling the station frame column; Figure 11 Diagram showing the installation of a second steel support above the station's central slab. Figure 1 ; Figure 12 Diagram showing the installation of a second steel support above the station's central slab. Figure 2 ; Figure 13 Diagram showing the installation of a second steel support above the station's central slab. Figure 3 ; Figure 14 Details on installing a second steel support above the station's central slab Figure 1 ; Figure 15 Details on installing a second steel support above the station's central slab Figure 2 ; Figure 16 Illustration of an upward-turning beam installed above the station roof slab Figure 1 ; Figure 17 Illustration of an upward-turning beam installed above the station roof slab Figure 2 ; Figure 18 Detailed drawing of the upward-turning beam installed above the station roof slab; Figure 19 Detailed drawing of the upward-turning beam; Figure 20 3D schematic diagram of triangular steel bracket Figure 1 ; Figure 21 3D schematic diagram of triangular steel bracket Figure 2 ; Figure 22 This is a schematic diagram of the assembly of the triangular steel bracket and the upward-turning beam; Figure 23 Schematic diagram of assembling triangular steel brackets for the flip beams on the station roof slab Figure 1 ; Figure 24 Schematic diagram of assembling triangular steel brackets for the flip beams on the station roof slab Figure 2 ; Figure 25 Schematic diagram of a new cap beam installed above the triangular steel support; Figure 26 Diagram showing the connection of the first concrete support above the station roof slab. Figure 1 ; Figure 27 Diagram showing the connection of the first concrete support above the station roof slab. Figure 2 ; Figure 28 Detailed drawing of the first concrete support above the station roof slab; Figure 29 This is a cross-sectional view showing the completion of the station's structural construction. Figure 30 This is a three-dimensional schematic diagram showing the completion of the station structure construction. Figure 31 A cross-sectional view of the ventilation shaft foundation pit excavation up to the bottom of the first concrete support; Figure 32 A cross-sectional view showing the completion of the first layer of concrete support for the ventilation shaft foundation pit; Figure 33 Cross-sectional view of the steel support after the foundation pit of the ventilation shaft has been excavated to the bottom of the second steel support and the steel support has been constructed. Figure 34 A cross-sectional view of the ventilation shaft foundation pit excavated to the design elevation; Figure 35 This is a cross-sectional view of the completed ventilation shaft structure. Figure 36 This is a cross-sectional view showing the completed construction of the post-cast strip between the ventilation shaft structure and the station structure. Figure 37 Cross-sectional view showing the complete removal of the two supports; Figure 38 This is a cross-sectional view of the completed backfilling of the foundation pit.

[0023] Attached diagrams and their descriptions: 1. Station retaining piles; 2. Crown beam; 3. Retaining wall; 4. Station floor slab; 5. Station middle slab; 6. Station roof slab; 7. Station side wall; 8. Station frame column; 9. Ventilation shaft foundation pit retaining piles; 10. Ventilation shaft structure; 11. Ventilation shaft frame column; 12. First concrete support; 13. Second steel support; 14. Post-cast strip; 15. Steel pipe fixing bracket; 16. Semi-circular clamp; 17. Rectangular clamp; 18. Bottom pad; 19. End pad; 20. Upward-turning beam; 21. Anchor bolt; 22. Triangular steel bracket; 23. Newly built crown beam; 24. Horizontal continuous bracing. Detailed Implementation

[0024] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0025] like Figure 1-38 As shown, this invention provides a construction method for the connection section between the ventilation shaft and the main structure of a subway station, the specific implementation of which is as follows: Example 1: This embodiment describes the connection method of the second steel support 13 of the ventilation shaft foundation pit near the side of the existing station structure.

[0026] The second steel support 13 of the ventilation shaft foundation pit is supported on the side wall 7 of the station near the existing station structure. An end pad 19 is provided between the end of the steel support 13 and the side wall 7 of the station. Multiple bottom pads 18 are evenly arranged above the station middle plate 5 and placed below the steel support 13. The steel support 13 is assembled and fixed between the adjacent station frame columns 8 of the station structure based on the steel pipe fixing bracket 15.

[0027] The steel pipe fixing bracket 15 is welded from the upper wing plate, the web plate and the lower wing plate. A semi-circular clamp 16 is welded to one end of the steel pipe fixing bracket 15 and a rectangular clamp 17 is welded to the other end.

[0028] The semi-circular clamp 16 is provided with connecting plates at both ends, and no less than 4 bolt holes are evenly provided on the connecting plates; the inner diameter of the semi-circular clamp 16 is equal to the outer diameter of the steel support 13; the semi-circular clamps 16 on the two steel pipe fixing brackets 15 can be assembled into a circle by bolts.

[0029] The rectangular clamp 17 is provided with connecting plates at both ends, and no less than 3 bolt holes are evenly provided on the connecting plates; the rectangular clamps 17 on the two steel pipe fixing brackets 15 can be assembled with each other with bolts and fixed to the station frame column 8.

[0030] After the semi-circular clamps 16 at one end of the two steel pipe fixing brackets 15 are assembled with bolts and the steel support 13 is fixed, the rectangular clamps 17 at the other end of the two steel pipe fixing brackets 15 can be assembled with other rectangular clamps 17 and fixed to the two station frame columns 8 adjacent to the steel support 13.

[0031] The configuration of the steel pipe fixing bracket 15 is as follows: Figure 3 and Figure 4 As shown. The semi-circular clamps 16 on the two steel pipe fixing brackets 15 can be assembled into a circle by bolts, as shown. Figure 5 As shown. The configuration of fixing the steel support 13 after the two steel pipe fixing brackets 15 are assembled is as follows. Figure 6 As shown.

[0032] The rectangular clamps 17 on the two steel pipe fixing brackets 15 are assembled together with bolts to form a hollow rectangle. The dimensions of this hollow rectangle are the cross-sectional dimensions of the station frame column 8. Figure 7 As shown. The rectangular clamps 17 on the two steel pipe fixing brackets 15 can be assembled with bolts and fixed to the station frame column 8, as shown. Figure 8 As shown.

[0033] A steel pipe fixing bracket 15 can also be assembled with a single rectangular clamp 17, such as Figure 9As shown, a steel pipe fixing bracket 15 and a single rectangular clamp 17 are assembled and fixed to the station frame column 8 by bolts, as follows. Figure 10 As shown. This configuration is primarily used for securing the outermost steel support 13.

[0034] Steel support 13 is assembled and fixed between adjacent station frame columns 8 of the station structure based on steel pipe fixing bracket 15, such as... Figures 11-15 As shown.

[0035] After the semi-circular clamps 16 at one end of the two steel pipe fixing brackets 15 are assembled with bolts and the steel support 13 is fixed, the rectangular clamps 17 at the other end of the two steel pipe fixing brackets 15 can be assembled with other rectangular clamps 17 and fixed to the two station frame columns 8 adjacent to the steel support 13. Figure 14 As shown.

[0036] The bottom pad 18 serves to transfer the vertical weight of the steel support 13 to the station structure. The end pad 19 serves to transfer the load of the steel support 13 on the station side wall 7 to a larger area, preventing stress concentration that could cause cracks in the station side wall 7, crushing of the reinforced concrete, or even damage.

[0037] The steel support 13 is assembled and fixed between the adjacent station frame columns 8 of the station structure based on the steel pipe fixed bracket 15, so that the steel support 13 does not move under various working conditions and loads, and plays a role in fixing and restraining.

[0038] The proposed steel pipe fixing bracket 15 is welded from steel structure, simple to manufacture, and easy to assemble and disassemble. It can effectively constrain and fix the steel support 13, so that the end of the second steel support 13 of the ventilation shaft foundation pit near the existing station structure is supported on the station side wall 7. That is, the second steel support 13 of the ventilation shaft foundation pit is no longer supported on the station retaining pile 1, so the station retaining pile 1 can be cut and removed in advance.

[0039] In the traditional construction method, the second steel support 13 of the ventilation shaft foundation pit is directly supported on the station retaining pile 1, which means that the station retaining pile 1 can only be removed in batches after the ventilation shaft structure is completed, which makes it difficult to connect the ventilation shaft structure and the station structure.

[0040] Example 2: This embodiment describes the connection method of the first concrete support 12 of the ventilation shaft foundation pit close to the side of the existing station structure.

[0041] During the construction of the station structure, multiple upturned beams 20 are evenly installed on the station roof slab 6 directly above the two rows of station frame columns 8 on the side closest to the ventilation shaft structure in the area connecting the station structure and the ventilation shaft structure. Anchor bolts 21 are installed at both ends of the upturned beams 20; the anchor bolts 21 are located directly above the station frame columns 8.

[0042] During the subsequent construction of the ventilation shaft foundation pit, triangular steel supports 22 were installed on the upturned beam 20 of the station roof slab 6 based on the anchor bolts 21.

[0043] The triangular steel bracket 22 is welded from a base plate, vertical ribs, and diagonal ribs. The base plate has bolt holes at both ends that match the anchor bolts 21 at both ends of the upper beam 20. The cross-section of the vertical ribs and diagonal ribs is cross-shaped. A flat support plate is installed at the upper end of the vertical ribs.

[0044] When the triangular steel support 22 and the upward beam 20 are assembled together, the vertical ribs of the triangular steel support 22 should be set on the side closer to the ventilation shaft.

[0045] During the construction of the ventilation shaft foundation pit, formwork is erected, steel bars are tied, and concrete is poured at the upper ends of each triangular steel support 22 to form a new cap beam 23; a series of pads 18 are evenly placed between the new cap beam 23 and the station roof slab 6.

[0046] During the construction of the ventilation shaft foundation pit, the first concrete support 12 at the connection between the ventilation shaft structure and the station structure is connected at its end to the newly built cap beam 23.

[0047] Several horizontal bracing 24 are evenly installed between the newly built capping beam 23 and the station retaining pile capping beam 2 on the side away from the ventilation shaft foundation pit.

[0048] The horizontal support 24 is supported by steel pipes; the horizontal support 24 is set on the extension line of the first concrete support 12 at the connection between the ventilation shaft structure and the station structure.

[0049] During the construction of the station structure, multiple upward-turning beams 20 are evenly installed on the station roof slab 6 directly above the two rows of station frame columns 8 on the side closest to the ventilation shaft structure in the area connecting the station structure and the ventilation shaft structure. Figure 16 and Figure 17 As shown. Anchor bolts 21 are installed at both ends of the upward-turning beam 20. The anchor bolts 21 are located directly above the station frame column 8, as shown. Figure 18 and Figure 19 As shown, the station frame column 8 is located directly below the upturned beam 20, minimizing the impact on the reinforced concrete structure of the station when the load borne by the upturned beam 20 is transferred to the station structure.

[0050] The reinforcing bars of the upturned beam 20 and the station roof slab 6 are tied together, meaning that the reinforcing bars of the upturned beam 20 and the station roof slab 6 are tied simultaneously during construction. It should be able to bear the various distributed loads transmitted by the first concrete support 12 and the newly built cap beam 23 without buckling or failure.

[0051] Triangular steel support 22 configuration as follows Figure 20 and Figure 21 As shown, the overall shape is a right-angled triangle. A triangular steel bracket 22 is installed on the upward-turning beam 20 of the station roof slab 6 based on the anchor bolts 21, as shown... Figure 22 As shown. When the triangular steel bracket 22 and the upward-turning beam 20 are assembled together, the vertical ribs of the triangular steel bracket 22 should be set on the side closest to the ventilation shaft, such as... Figure 23 and Figure 24 As shown.

[0052] The triangular steel support 22 should be able to withstand the various distributed loads transmitted from the first concrete support 12 and the newly built cap beam 23 during operation without buckling or failure.

[0053] During the construction of the ventilation shaft foundation pit, formwork was erected at the upper ends of each triangular steel support 22, reinforcement was tied, and concrete was poured to form the new cap beam 23, as follows. Figure 25 As shown.

[0054] Based on the stress and self-weight of the first concrete support 12 and the newly built cap beam 23, the required number of triangular steel supports 22, i.e., the upturned beam 20, should be calculated so that the position of the upturned beam 20 can be reasonably and evenly arranged during the construction of the station structure.

[0055] During the construction of the ventilation shaft foundation pit, the first concrete support 12 at the connection between the ventilation shaft structure and the station structure is connected to the newly built capping beam 23. That is, the reinforcement binding of the first concrete support 12 and the newly built capping beam 23 is carried out simultaneously, and the reinforcement lap joint at the connection between the first concrete support 12 and the newly built capping beam 23 should meet the relevant specifications.

[0056] Several horizontal bracing 24 are evenly arranged between the newly constructed capping beam 23 and the station retaining pile capping beam 2 on the side away from the ventilation shaft foundation pit. The horizontal bracing 24 is set on the extension line of the first concrete support 12 at the connection between the ventilation shaft structure and the station structure, such as... Figures 26-28 As shown.

[0057] It is evident that during the construction of the ventilation shaft foundation pit, the first concrete support 12 at the connection between the ventilation shaft structure and the station structure no longer rests on the capping beam 2 of the existing station retaining pile 1, thus allowing the station retaining pile 1 to be cut and removed in advance.

[0058] In the traditional construction method, the first concrete support 12 of the ventilation shaft foundation pit is directly supported on the capping beam 2 of the station retaining pile 1, which means that the station retaining pile 1 can only be removed in batches after the ventilation shaft structure is completed, which makes it difficult to connect the ventilation shaft structure and the station structure. Example 3: This embodiment describes the construction method for the connection section between the ventilation shaft and the main structure of a subway station.

[0059] This invention is achieved using the following technical solution: a construction method for the connection section between a subway station ventilation shaft and the main station structure, characterized by comprising the following steps: Step 1: Construct the station foundation pit retaining piles and station structure, as detailed below: The station foundation pit retaining piles 1, capping beam 2, and retaining wall 3 are constructed in sequence; the station foundation pit is excavated in alternating layers and horizontal supports are constructed until the design elevation is reached; the station structure is constructed in stages and the supports are replaced until the station structure construction is completed; during the construction of the station structure, multiple upturned beams 20 are evenly set on the station roof slab 6 directly above the two rows of station frame columns 8 on the side closest to the ventilation structure in the area where the station structure and ventilation structure are connected. Anchor bolts 21 are pre-embedded at both ends of the upturned beams 20, and the anchor bolts 21 are located directly above the station frame columns 8; The cross-sectional view of the station's main structure upon completion is shown below. Figure 29 As shown, the three-dimensional schematic diagram is as follows: Figure 30 As shown. For details regarding the relevant features and requirements of the upward-turning beam 20, please refer to Example 2. Step Two: Construct 9 retaining piles for the wind tunnel foundation pit, and excavate in layers to the first concrete support at elevation 12, as detailed below: Construct the retaining piles 9 and the capping beam and lattice column of the ventilation shaft foundation pit, and excavate the ventilation shaft foundation pit in layers to the bottom elevation of the first concrete support 12; cut and remove the retaining wall 3, capping beam 2, and station retaining pile 1 between the area connecting the station structure and the ventilation shaft structure to the soil excavation surface elevation; install triangular steel brackets 22 on the upturned beam 20 of the station roof slab 6 based on the anchor bolts 21; For details on the connection requirements between the triangular steel support 22 and the upward-turning beam 20, please refer to Example 2. The cross-sectional view of the foundation pit after this step is completed is shown below. Figure 31 As shown.

[0060] Step 3: Construct the first layer of concrete support 12 for the wind tunnel foundation pit, as detailed below: Formwork is erected, steel bars are tied, and concrete is poured at the upper ends of each triangular steel support 22 to form a new cap beam 23; the first concrete support 12 at the connection between the ventilation shaft structure and the station structure is connected to the new cap beam 23; several horizontal bracing 24 are evenly set between the new cap beam 23 and the station retaining pile cap beam 2 on the side away from the ventilation shaft foundation pit. The connection characteristics and requirements of the first concrete support 12, the newly built cap beam 23, and the horizontal bracing 24 are detailed in Example 2. Figure 32 As shown.

[0061] Step 4: Excavate the ventilation shaft foundation pit in layers to the elevation of the second steel support 13, and construct the second steel support 13 as follows: The ventilation shaft foundation pit is excavated in layers to the bottom elevation of the second steel support 13; the station retaining piles 1 between the station structure and the ventilation shaft structure are cut and removed to the soil excavation surface elevation; the second steel support 13 is constructed, with the end of the second steel support 13 near the existing station structure supported on the station side wall 7; each steel support 13 is assembled and fixed between the adjacent station frame columns 8 of the station structure based on the steel pipe fixing bracket 15. The connection characteristics and requirements between steel support 13 and steel pipe fixing bracket 15 are detailed in Example 1. The cross-sectional view of the foundation pit after this step is completed is shown below. Figure 33 As shown.

[0062] Step 5: Excavate the ventilation shaft foundation pit in layers to the design elevation, as detailed below: The ventilation shaft foundation pit was excavated in layers to the design elevation, and the station retaining pile 1 between the station structure and the ventilation shaft structure was simultaneously cut and removed to the soil excavation surface elevation. The cross-sectional view of the foundation pit after this step is completed is as follows: Figure 34 As shown.

[0063] Step Six: Construct the pavilion structure, as detailed below: The ventilation shaft base slab and waterproof layer are constructed, followed by the construction of the ventilation shaft base slab, side walls, and top slab structure. Ventilation shaft frame columns 11 are set in the area where the station structure and ventilation shaft structure are connected. The ventilation shaft base slab and the station middle slab 5 are connected by rebar and concrete pouring to form an integral whole. The construction of the waterproof layer on the ventilation shaft's base slab was carried out in accordance with relevant specifications. The ventilation shaft's base slab and the station's central slab 5 are directly connected to form a single unit, without the need for a post-pouring strip. Since the existing station retaining piles 1 have been cut and removed, there are no obstacles between the ventilation shaft's base slab and the station's central slab 5, allowing for direct connection without the need for a post-pouring strip. This improves the construction quality of the connection and reduces the risk of water seepage at the subsequent connection point.

[0064] The cross-sectional view of the foundation pit after this step is completed is as follows: Figure 35 As shown.

[0065] Step 7: Construct the post-pouring strip 14 for the roof slab of the wind pavilion structure, as detailed below: After the post-construction settlement of the ventilation shaft structure meets the relevant requirements, the post-pouring strip 14 between the top slab of the ventilation shaft structure and the top slab of the station 6 is constructed. Since the existing station retaining piles 1 between the ventilation shaft roof slab and the station roof slab 6 have been cut and removed, eliminating any obstructions, the post-cast strip 14 between the ventilation shaft roof slab and the station roof slab 6 no longer needs to be divided into sections or blocks. This reduces the number of post-cast strip joints, improves the construction quality of the interconnections, and lowers the risk of water seepage at subsequent connections. The cross-sectional view of the foundation pit after this step is shown below. Figure 36 As shown.

[0066] Step 8: Remove the horizontal supports for the ventilation shaft foundation pit, as detailed below: Remove the steel pipe fixing bracket 15, remove the second steel support 13 of the ventilation shaft foundation pit; cut and remove the first concrete support 12 and the newly built cap beam 23, remove the horizontal support 24; remove the triangular steel bracket 23. This involves completely dismantling the second steel support 13, the first concrete support 12, and the temporary triangular steel bracket 23. The resulting cross-sectional view of the foundation pit after this step is shown below. Figure 37 As shown.

[0067] Step Nine: Waterproofing of the ventilation shaft roof and backfilling of the foundation pit, as detailed below: According to relevant specifications, a waterproof layer is applied to the roof slab of the pavilion structure. Then, the foundation pit is backfilled in layers according to relevant requirements (or the planned roadbed and pavement are constructed) until the project is completed. The cross-sectional view of the foundation pit after this step is shown below. Figure 38 As shown.

[0068] In the description of the above construction steps, conventional construction content and procedures that are well-known in the field have been simplified or omitted, and this should not be interpreted as an incompleteness of the proposed construction method. The description of the construction method focuses on the substantive aspects that differ from traditional construction methods. Conventional construction content, techniques, and related requirements will not be elaborated upon in detail.

[0069] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A construction method for the connection section between the ventilation shaft and the main structure of a subway station, characterized in that, Includes the following steps: Step 1: Construct the station foundation pit retaining piles and station structure, as detailed below: The station foundation pit retaining piles (1), capping beams (2), and retaining walls (3) are constructed in sequence. The station foundation pit is excavated in alternating layers and horizontal supports are constructed until the design elevation is reached. The station structure is constructed in stages and the supports are replaced until the station structure construction is completed. During the construction of the station structure, multiple upturned beams (20) are evenly set on the station roof plate (6) above the two rows of station frame columns (8) on the side of the ventilation shaft structure in the area where the station structure and ventilation shaft structure are connected. Anchor bolts (21) are pre-embedded at both ends of the upturned beams (20). The anchor bolts (21) are located directly above the station frame columns (8). Step 2: Construct retaining piles (9) for the wind tunnel foundation pit and excavate in layers to the elevation of the first concrete support (12), as detailed below: Construct the retaining piles (9) and the top capping beam and lattice column of the ventilation shaft foundation pit, and excavate the ventilation shaft foundation pit in layers to the bottom elevation of the first concrete support (12); cut and remove the retaining wall (3), capping beam (2), and station retaining piles (1) between the station structure and the ventilation shaft structure to the soil excavation surface elevation; install triangular steel brackets (22) on the upturned beam (20) of the station top plate (6) based on the anchor bolts (21); Step 3: Construct the first layer of concrete support for the wind tunnel foundation pit (12); Step 4: Excavate the ventilation shaft foundation pit in layers to the elevation of the second steel support (13), and construct the second steel support (13). Step 5: Excavate the ventilation shaft foundation pit in layers to the design elevation, and simultaneously cut and remove the station retaining piles (1) between the station structure and the ventilation shaft structure to the soil excavation surface elevation; Step Six: Constructing the pavilion structure includes: The ventilation shaft base slab and waterproof layer are constructed, and the ventilation shaft base slab, side walls and top slab structure are constructed in sequence; ventilation shaft frame columns (11) are set in the area where the station structure and ventilation shaft structure are connected; the ventilation shaft base slab and the station middle slab (5) are connected by planting steel bars and pouring concrete to form an integral whole; Step 7: After the post-construction settlement of the ventilation shaft structure meets the relevant requirements, construct the post-cast strip (14) between the top slab of the ventilation shaft structure and the top slab of the station (6). Step 8: Remove the horizontal supports of the ventilation shaft foundation pit; Step Nine: Waterproofing of the ventilation shaft roof and backfilling of the foundation pit, until the project is completed.

2. The construction method for the connection section between the ventilation shaft and the main structure of a subway station as described in claim 1, characterized in that, In step two, the process of constructing the first concrete support (12) for the wind tunnel foundation pit includes: setting up formwork, binding steel bars, and pouring concrete at the upper end of each triangular steel support (22) to form a new cap beam (23); connecting the end of the first concrete support (12) at the connection between the wind tunnel structure and the station structure to the new cap beam (23); and evenly setting multiple horizontal bracing (24) between the new cap beam (23) and the cap beam (2) of the station retaining piles on the side away from the wind tunnel foundation pit.

3. The construction method for the connection section between the ventilation shaft and the main structure of a subway station as described in claim 1, characterized in that, In step four, the ventilation shaft foundation pit is excavated in layers to the elevation of the second steel support (13). The process of constructing the second steel support (13) includes: The ventilation shaft foundation pit is excavated in layers to the bottom elevation of the second steel support (13); the station retaining piles (1) between the station structure and the ventilation shaft structure are cut and removed to the soil excavation surface elevation; the second steel support (13) is constructed, and the end of the second steel support (13) near the existing station structure is supported on the station side wall (7). Each steel support (13) is assembled and fixed between the adjacent station frame columns (8) of the station structure based on the steel pipe fixing bracket (15).

4. The construction method for the connection section between the ventilation shaft and the main structure of a subway station as described in claim 3, characterized in that, Step eight, the process of dismantling the horizontal supports of the ventilation shaft foundation pit includes: Remove the steel pipe fixing bracket (15), remove the second steel support (13) of the ventilation shaft foundation pit; cut and remove the first concrete support (12), build a new crown beam (23), remove the horizontal support (24); remove the triangular steel bracket (23).

5. The construction method for the connection section between the ventilation shaft and the main structure of a subway station as described in claim 1, characterized in that, The triangular steel support (22) is welded from a base plate, vertical ribs, and diagonal ribs. The base plate has bolt holes at both ends that match the anchor bolts (21) at both ends of the upper beam (20). The cross-sections of the vertical and diagonal ribs are cross-shaped. A flat support plate is provided at the upper end of the vertical rib. When the triangular steel support (22) is assembled with the upper beam (20), the vertical ribs of the triangular steel support (22) should be set on the side closer to the ventilation shaft.

6. The construction method for the connection section between the ventilation shaft and the main structure of a subway station as described in claim 1, characterized in that, The horizontal support (24) is supported by steel pipes; the horizontal support (24) is set on the extension line of the first concrete support (12) at the connection between the ventilation shaft structure and the station structure.

7. The construction method for the connection section between the ventilation shaft and the main structure of a subway station as described in claim 4, characterized in that, The steel pipe fixing bracket (15) is welded from an upper wing plate, a web plate, and a lower wing plate. A semi-circular clamp (16) is welded to one end of the steel pipe fixing bracket (15), and a rectangular clamp (17) is welded to the other end. Connecting plates are provided at both ends of the semi-circular clamp (16), and no less than 4 bolt holes are evenly provided on the connecting plates. The inner diameter of the semi-circular clamp (16) is equal to the outer diameter of the steel support (13). The semi-circular clamps (16) on the two steel pipe fixing brackets (15) can be assembled into a circle by bolts. Connecting plates are provided at both ends of the rectangular clamp (17), and no less than 3 bolt holes are evenly provided on the connecting plates. The rectangular clamps (17) on the two steel pipe fixing brackets (15) can be assembled into a circle by bolts and fixed to the station frame column (8).

8. The construction method for the connection section between the ventilation shaft and the main structure of a subway station as described in claim 4, characterized in that, After the semi-circular clamps (16) at one end of the two steel pipe fixing brackets (15) are assembled with bolts and the steel support (13) is fixed, the rectangular clamps (17) at the other end of the two steel pipe fixing brackets (15) can be assembled with other rectangular clamps (17) and fixed to the two station frame columns (8) adjacent to the steel support (13).

9. The construction method for the connection section between the ventilation shaft and the main structure of a subway station as described in claim 4, characterized in that, The end of the second steel support (13) of the ventilation shaft foundation pit is supported on the side wall (7) of the station near the existing station structure. An end pad (19) is provided between the end of the steel support (13) and the side wall (7). Multiple bottom pads (18) are evenly arranged above the station middle plate (5) and placed below the steel support (13).

10. A construction method for the connection section between a subway station ventilation shaft and the main station structure as described in claim 4, characterized in that, Multiple bottom pads (18) are evenly arranged between the newly built crown beam (23) and the station roof slab (6).

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