Mechanical method air shaft construction method and air shaft structure

Abstract

The application discloses a mechanical air shaft construction method and an air shaft structure, and specifically comprises the following steps: S1, determining the construction position of the underground negative one layer structure; S2, constructing the enclosure structure, the foundation pit and the overall structure of the interval air shaft outside; S3, shield tunnel construction: while the interval air shaft is constructed, shield tunnel construction is performed through shield tunneling below the interval air shaft; S4, constructing the vertical air duct between the interval air shaft and the shield tunnel; S5, connecting and fixing the first pipe section and the bottom plate of the interval air shaft and performing water stop construction at the joint; and S6, constructing the internal structure of the interval air shaft: setting the horizontal air valve wall, the vertical air valve wall and the stairwell in the interval air shaft. The application realizes independent construction of the air shaft and the shield tunnel, improves the flexibility of construction period arrangement, and significantly reduces the influence of construction on the surrounding environment.

Description

Technical Field

[0001] This invention belongs to the field of urban rail transit technology, specifically relating to a mechanical method for constructing ventilation shafts and the structure of ventilation shafts. Background Technology

[0002] With the continuous expansion and extension of urban subway networks, station spacing is constantly increasing. For sections with long tunnels and high traffic density, there is a possibility of multiple trains operating simultaneously within a single tunnel section. In the design of long subway sections, intermediate ventilation shafts are generally required to meet the functions of tunnel ventilation and cooling, pressure relief and drag reduction, and fire smoke extraction, providing normal and emergency ventilation services. In existing technologies, the ventilation shaft is usually constructed first, followed by the tunnel boring machine (TBM) receiving and launching within the shaft. The ventilation shaft is typically a two-story underground structure (for shallower lines) or a multi-story underground structure (for deeper lines). In the project, cast-in-place piles or diaphragm walls are constructed first as the retaining structure for the ventilation shaft pit, followed by the construction of the main structure, including the bottom slab, side walls, middle slab, and top slab. After several months, once the ventilation shaft structure is completed, the TBM can then begin its excavation or receiving operation.

[0003] The above-mentioned construction process has several drawbacks: First, the construction of the shield tunnel requires the completion of the main structure of the ventilation shaft before it can be ready for receiving or launching within the shaft. Furthermore, in actual construction, besides the construction period of the ventilation shaft itself, underground ventilation shafts typically use the open-cut method, requiring the relocation of surface traffic and underground pipelines before construction. The coordination and relocation work among various departments is lengthy, placing even greater demands on construction conditions. This undoubtedly limits the flexible scheduling of the shield tunneling construction period, preventing the project from operating efficiently and synchronously, and even causing delays. Second, ventilation shafts are typically underground structures with two or more levels. The retaining structure, excavation, and main structure of the foundation pit are large-scale, costly, and have a significant negative impact on the surrounding environment. Furthermore, the platform level is generally only used to provide construction space and train passage space during operation, resulting in a relatively singular functional attribute and a waste of engineering resources. Third, in order to minimize the excavation depth of the ventilation shaft foundation pit, existing technologies place the ventilation shafts at shallower locations along the railway line. This leads to the use of a non-optimal longitudinal slope for the railway line, and the location of the ventilation shafts is severely restricted, causing a significant impact on the surrounding environment. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a mechanical method for constructing ventilation shafts and a corresponding ventilation shaft structure. This method overturns the traditional construction sequence, which requires first constructing the ventilation shaft within the tunnel section and then receiving and launching the tunnel boring machine (TBM) within it. It enables independent construction of the ventilation shaft and the TBM tunnel, improving the flexibility of the construction schedule. Compared to the traditional method, which necessitates excavating deep foundation pits and constructing the second or even third basement level ventilation shaft structure before TBM reception and launching, this patent utilizes a vertical pipe jacking tunnel constructed mechanically as a ventilation channel. This mechanical construction of the ventilation shaft eliminates the need for the construction of the second and third basement levels, significantly improving construction efficiency and safety while substantially reducing project costs. Furthermore, compared to the traditional method of excavating deep foundation pits, this patent's mechanical construction method for the ventilation shaft significantly reduces the environmental impact of construction, further promoting green construction practices.

[0005] To achieve the above objectives, the technical solution is as follows:

[0006] A mechanical ventilation shaft construction method specifically includes the following steps:

[0007] S1, Determine the construction location of the underground basement structure: Based on the project plan and site conditions, determine the construction location of the ventilation shaft in the section;

[0008] S2, Construction of retaining structure, foundation pit and external overall structure of the interval ventilation shaft: After the retaining structure of the interval ventilation shaft foundation pit is constructed according to the construction location, the foundation pit is excavated, and then the main structure of the underground floor and the ground structure of the interval ventilation shaft are constructed, and the piston ventilation shaft is constructed on the top plate of the interval ventilation shaft.

[0009] S3, Shield tunnel construction: While the ventilation shaft of the section is being constructed, a shield tunnel is being constructed below the ventilation shaft by shield excavation.

[0010] S4, construct the vertical ventilation duct between the ventilation shaft and the shield tunnel; construct the jacking starting hole of the ventilation duct at the top of the shield tunnel, and carry out the jacking operation until it reaches the jacking receiving hole of the bottom plate of the ventilation shaft, thus completing the construction of the vertical ventilation duct.

[0011] S5, Connect and fix the first jacking pipe section to the bottom plate of the interval ventilation shaft and perform water-stopping construction at the joint: Weld and fix the first jacking pipe section to the bottom plate of the interval ventilation shaft, and permanently seal the joint between the first jacking pipe section of the vertical air duct and the bottom plate of the interval ventilation shaft.

[0012] S6, Construction of the internal structure of the ventilation shaft: Installation of horizontal and vertical air valve walls and stairwells inside the ventilation shaft, and installation of fans and various air valves.

[0013] Furthermore, in S3, the pipe segments used for setting the vertical ventilation ducts in the shield tunnel are made of composite steel pipe segments, while the remaining sections are made of full-ring reinforced concrete pipe segments.

[0014] Furthermore, in step S4, the centerline of the jacking pipe initiation hole is aligned and coincides with the centerline of the jacking pipe receiving hole.

[0015] Furthermore, in S4, before the pipe jacking operation is carried out, a pipe jacking machine is installed directly below the starting hole of the air duct pipe jacking, and the first pipe jacking section of the air duct is spliced. Through the action of the lifting cylinder of the pipe jacking machine, the pipe jacking machine head is lifted into the starting collar, so that the two circumferential sealing water-stop brushes of the pipe jacking machine are in close contact with the outer wall of the pipe jacking equipment head.

[0016] Furthermore, in step S4, the first jacking pipe section is fixedly connected to the tail end of the jacking machine. During the vertical jacking operation, after the first jacking pipe section is lifted one section upwards, a new pipe section is spliced ​​below. After each section is lifted, a new pipe section is spliced. The circumferential joint between each two pipe sections is firmly welded with bevel welds until the first jacking pipe section is lifted to the bottom plate of the ventilation shaft. Then, the head of the jacking machine is removed, and the top of the first jacking pipe section is connected to the jacking receiving hole of the ventilation shaft to complete the construction of the vertical ventilation duct. Finally, the last jacking pipe section of the ventilation duct is welded and fixed to the shield tunnel.

[0017] A ventilation shaft structure includes a main structure located on the first basement level and a vertical ventilation duct connected to a tunnel;

[0018] The tunnel includes a left-line tunnel and a right-line tunnel, which are arranged parallel to each other and extend horizontally at both ends. Trains travel in opposite directions within the left-line and right-line tunnels; the direction of approach is forward, and the direction of departure is backward. Each of the left-line and right-line tunnels has two or more pipe jacking starting holes.

[0019] The main structure is a cuboid structure, including a staircase area and a ventilation area arranged side by side. The top plate of the ventilation area is equipped with two piston air shaft valves, which are arranged diagonally. The bottom plate of the ventilation area has two or more jacking pipe receiving holes on each side. A jacking pipe receiving hole ring beam is provided at each jacking pipe receiving hole. The first jacking pipe section of the air duct is installed in the jacking pipe receiving hole. A horizontal air valve wall is provided at the upper end of the first jacking pipe section.

[0020] A vertical air valve is provided between each pair of the jacking pipe receiving holes on the right side of the base plate, and a vertical air valve is also provided between each pair of the jacking pipe receiving holes on the left side of the base plate; a fan is provided between the jacking pipe receiving holes on the right side of the base plate and the jacking pipe receiving holes on the left side of the base plate at the same horizontal position, and a vertical air valve is provided at each end of the fan.

[0021] The vertical centerline of each of the pipe jacking starting holes is aligned and coincides with the vertical centerline of a pipe jacking receiving hole; each of the pipe jacking receiving holes is connected to the pipe jacking starting hole of the tunnel through a ventilation duct.

[0022] A stairwell is located at the corner of the main structure where the piston air shaft and air valve are located, and a partition wall is provided between the stairwell and the adjacent piston air shaft and air valve.

[0023] Furthermore, the ring beam of the jacking pipe receiving hole has a square structure.

[0024] Furthermore, a stairwell is provided on one side of the stairwell area, the stairwell extends upward to above ground level, and a workroom is provided on its top, the workroom being located above ground level.

[0025] Furthermore, a partition wall is provided between the stairwell area and the ventilation area.

[0026] Furthermore, the piston ventilation shaft valve extends upwards to above ground level, and a ventilation pavilion is installed at its top above ground level.

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

[0028] First, the vertical pipe jacking mechanical method for forming vertical ventilation ducts allows for independent construction of the shield tunnel and the ventilation shaft, with no inter-task constraints. This changes the existing technology that requires the construction of the ventilation shaft structure first, followed by shield tunneling, eliminating the constraint of ventilation shaft construction progress on shield tunneling progress and making the scheduling of ventilation shaft and shield tunneling more flexible and efficient. Second, compared to the existing two- or even multi-level underground ventilation shaft structures, this patent uses a single-level underground ventilation shaft structure, reducing the excavation depth, lowering the risk of excavation, reducing the scale of excavation earthwork, retaining structures, and the main ventilation shaft structure, shortening the construction period, and significantly reducing project investment. Third, the vertical pipe jacking mechanical method provided by this patent provides ventilation... First, the individual ventilation duct jacking pipes are relatively small in size, making construction easier. This not only meets the ventilation requirements of the tunnel section, but also utilizes a mechanical jacking process, ensuring efficient and safe construction and significantly reducing the impact on the surrounding environment, further promoting high-quality and green construction. Second, this patented technology can solve the mutual constraints between the longitudinal slope design of the line and the site selection of the ventilation shaft. The excavation depth of the ventilation shaft pit no longer needs to be increased due to the burial depth of the line, and the longitudinal profile design of the line is no longer limited by the site selection conditions of the ventilation shaft. As a result, the longitudinal slope of the line can adopt the optimal solution, and the ventilation shaft can be selected in a location with less impact on the surrounding environment and less difficulty in project implementation, reducing the difficulty of project implementation, construction risks, and project investment, and achieving the goal of saving resources and being environmentally friendly. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the construction method steps of the present invention;

[0030] Figure 2 This is a schematic diagram of the top plate of the ventilation shaft structure of the present invention;

[0031] Figure 3 This is a schematic diagram of the low plate of the ventilation shaft structure of the present invention;

[0032] Figure 4 for Figure 2 or Figure 3 Sectional view of the structure in section 1-1;

[0033] Figure 5 for Figure 2 or Figure 3 Sectional view of the structure in section 2-2;

[0034] Figure 6 for Figure 2 or Figure 3 Sectional view of the structure in section 3-3;

[0035] Figure 7 This is a construction diagram showing the left tunnel in the pipe jacking acceptance state and the right tunnel in the pipe jacking starting state in the construction method of the present invention;

[0036] Figure 8 This is a diagram of the starting state device for the right-line vertical pipe jacking in the construction method of the present invention;

[0037] Figure 9 for Figure 8 Enlarged view of the A-structure in the middle;

[0038] Figure 10 This is a schematic diagram of the water-stopping construction structure of the present invention. Figure 1 ;

[0039] Figure 11 This is a schematic diagram of the water-stopping construction structure of the present invention. Figure 2 .

[0040] Attached reference numerals: 1-1, Top slab of ventilation shaft; 1-2, Side wall of ventilation shaft; 1-3, Bottom slab of ventilation shaft; 1-4, First piston ventilation shaft; 1-5, Side wall of first piston ventilation shaft; 1-6, Second piston ventilation shaft; 1-7, Side wall of second piston ventilation shaft; 1-8, Enclosure structure; 1-9, Ring beam of pipe jacking receiving hole; 1-10, Staircase passage; 1-11, Side wall of staircase passage; 1-12, Staircase; 1-13, Work area; 1-14, Ventilation shaft; 1-15, Concrete pad of pipe jacking receiving hole;

[0041] 2-1. Vertical air duct; 2-2. First jacking pipe section; 2-3. Last jacking pipe section; 2-4. Weld of jacking pipe section;

[0042] 3. Left tunnel; 3-1. Left composite steel segment;

[0043] 4. Right-line tunnel; 4-1. Right-line composite steel pipe segment; 4-2. Reinforced concrete pipe segment; 4-3. Concrete pipe segment block; 4-4. Glass fiber reinforcement; 4-5. Micro-expansion concrete; 4-6. Water-stop ring for steel-concrete pipe segment joints;

[0044] 5-1. Pipe jacking starting collar; 5-2. Triangular reinforcing rib plate; 5-3. First sealing water-stop brush; 5-4. Second sealing water-stop brush; 5-5. Pipe jacking machine; 5-6. Connecting weld; 5-7. Annular jacking iron; 5-8. Lifting cylinder; 5-9. Pipe jacking working platform; 5-10. Lifting base;

[0045] 6-1. First piston ventilation shaft valve; 6-2. Second piston ventilation shaft valve; 6-3. First fan; 6-4. Second fan; 6-5. Vertical valve; 6-6. Horizontal valve;

[0046] 7. Pre-embedded L-shaped steel pipe; 7-1. Temporary grouting pipe; 7-2. Interface between the bottom of the base plate and the outer wall of the jacking pipe; 7-3. Fixing steel plate. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] It should be noted that when a device or element is referred to as being "connected to" another device or element, it can be directly connected to the other device or element or indirectly connected to that other device or element.

[0049] In the description of this invention, it should be noted that the terms "deep," "upper," "lower," "left," "right," "vertical," "horizontal," "horizontal," "longitudinal," "top," "bottom," "inner," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0050] Example 1

[0051] This invention provides a mechanical method for constructing ventilation shafts, such as... Figure 1 As shown, the specific steps include:

[0052] S1. Determine the construction location of the underground floor structure: Based on the project schedule and site conditions, determine the construction location of the ventilation shaft in the section; in actual situations, it is possible to flexibly choose to construct the ventilation shaft in the section first or the shield tunnel first, or both simultaneously.

[0053] S2, Construction of retaining structure, foundation pit and external overall structure of the interval ventilation shaft: After the construction of the retaining structure 1-8 of the interval ventilation shaft foundation pit according to the construction location, the foundation pit is excavated, and then the main structure of the underground floor and the ground structure of the interval ventilation shaft are constructed, and the piston ventilation shaft is constructed on the top plate of the interval ventilation shaft.

[0054] S3, Shield tunnel construction: While constructing the ventilation shaft in the section, tunnel construction is carried out below the ventilation shaft using shield tunneling.

[0055] During tunnel construction, the two rings before and after the tunnel interface with the vertical ventilation duct 2-1, namely the pipe sections used to set the starting holes for pipe jacking, use composite steel pipe segments. The starting hole reserved at the top of the composite steel pipe segments in the tunnel is divided into concrete pipe segments 4-2, in which the reinforcing bars are glass fiber bars 4-4 that can be cut by the pipe jacking tool. The two ends of the glass fiber bars 4-4 pass through the perforations in the wall of the starting hole of the steel pipe segment. The remaining sections of the tunnel use reinforced concrete pipe segments 4-2.

[0056] S4, construct the vertical ventilation duct 2-1 between the ventilation shaft and the shield tunnel; construct the jacking starting hole of the ventilation duct at the top of the shield tunnel, and carry out the jacking operation until it reaches the jacking receiving hole of the bottom plate of the ventilation shaft, thus completing the construction of the vertical ventilation duct 2-1.

[0057] In this step, such as Figure 8 As shown, before the pipe jacking operation, the pipe jacking machine 5-5 is installed directly below the starting hole of the air duct pipe jacking, and the first pipe section 2-2 of the vertical air duct 2-1 is spliced. Through the action of the lifting cylinder 5-8 of the pipe jacking machine 5-5, the head of the pipe jacking machine 5-5 is lifted into the starting collar of the pipe jacking machine, so that the two circumferential sealing water-stop brushes of the pipe jacking machine 5-5 are in close contact with the outer wall of the pipe jacking equipment head.

[0058] Among them, the contact surface between the composite steel pipe segment and the concrete pipe segment 4-3 at the starting hole of the jacking pipe is equipped with two layers of water-stopping rubber rings; the top steel pipe segment cavity within a certain range on the outer wall of the jacking pipe starting ring, mainly the connection section between the concrete pipe segment 4-3 and the steel pipe segment, is filled with micro-expansion concrete 4-5; after the steel pipe segment is assembled, the jacking pipe starting ring 5-1 is installed on the top. The top surface of the jacking pipe starting ring 5-1 is curved, and the top surface is welded tightly to the inner wall of the steel pipe segment. Triangular reinforcing ribs 5-2 are welded at the interface between the jacking pipe starting ring 5-1 and the steel pipe segment; Figure 9As shown, the inner wall of the lower end of the jacking starting sleeve 5-1 is provided with two sealing and water-stopping brushes along the circumference, including the first sealing and water-stopping brush 5-3 and the second sealing and water-stopping brush 5-4. The second sealing and water-stopping brush 5-3 is set above the first sealing and water-stopping brush 5-4, and plays a role in sealing and water-stopping during the jacking starting and lifting construction.

[0059] Before installing the pipe jacking machine 5-5, a lifting base 5-10 is first installed at the bottom of the tunnel directly below the corresponding air duct installation position to provide the pipe jacking propulsion reaction force. Above the lifting base 5-10 is the pipe jacking operation platform. Four lifting cylinders are evenly distributed on the pipe jacking operation platform along the plane projection of the pipe wall. A ring-shaped jacking iron 5-7 is placed on the top surface of the lifting cylinder to provide a uniform lifting thrust to the pipe section.

[0060] In this embodiment, the lower end of each vertical ventilation duct 2-1 is connected to the pre-reserved jacking starting hole at the top of the tunnel, and its upper end is connected to the bottom plate of the ventilation area. The overall height of each vertical ventilation duct 2-1 is the vertical distance between the top of the tunnel and the bottom of the ventilation shaft bottom plate 1-3. The vertical ventilation duct 2-1 structure is constructed using pipe jacking technology. The pipe sections are made of steel with an outer diameter D = 2m and an inner diameter d = D - 2t, where t is the steel pipe wall thickness, t = t0 + t1, t0 is the calculated thickness required for structural load-bearing, and t1 is the calculated thickness for corrosion during the structure's service life. Each pipe section is 1m long, and the sections are joined by bevel welding.

[0061] S5, Connect and fix the first jacking pipe section 2-2 to the bottom plate of the inter-section ventilation shaft and carry out water-stopping construction at the joint: Weld and fix the first jacking pipe section 2-2 to the bottom plate of the inter-section ventilation shaft, and permanently seal the joint between the first jacking pipe section 2-2 of the vertical duct and the bottom plate of the inter-section ventilation shaft.

[0062] Specifically, the water-stopping construction method is as follows:

[0063] The water-stopping construction method is as follows:

[0064] S501, When constructing the base plate, L-shaped steel plates 7 are pre-embedded along the inner perimeter of the ring beam 1-9 of the jacking pipe receiving hole, in order to facilitate welding with the first jacking pipe section 2-2;

[0065] S502 After receiving the first jacking pipe section 2-2, a temporary grouting pipe 7-1 is inserted into the gap between the jacking pipe receiving hole ring beam 1-9 and the first jacking pipe section 2-2 to grout and stop water at the interface between the bottom of the base plate and the outer wall of the first jacking pipe section 2-2.

[0066] S503 After grouting is completed, micro-expansion concrete 4-5 is filled in the gap between the receiving hole ring beam 1-9 of the jacking pipe and the first jacking pipe section 2-2 to fill the gap tightly and at the same time play a role in water stop.

[0067] S504, by fixing steel plate 7-3, the pre-embedded L-shaped steel plate 7 of the jacking pipe receiving hole ring beam 1-9 is welded and fixed to the outer wall of the first jacking pipe section 2-2, so as to fix the pipe section and seal the water, thereby achieving the purpose of fixing and permanent water sealing.

[0068] S6, Construction of the internal structure of the ventilation shaft: Installation of the horizontal air valve 6-6 wall, the vertical air valve 6-5 wall, and the stairwells 1-12 inside the ventilation shaft, and installation of the fan and each air valve.

[0069] In this embodiment, in S3, the pipe segment used to install the vertical ventilation duct 2-1 in the shield tunnel is made of composite steel pipe segment, and the remaining sections are made of full-ring reinforced concrete pipe segment 4-2.

[0070] In this embodiment, in S4, the center line of the jacking pipe starting hole is aligned and coincides with the center line of the jacking pipe receiving hole.

[0071] In this embodiment, during the pipe jacking operation in step S4, the first pipe section 2-2 is connected to the tail end of the pipe jacking machine head and welded in place. During vertical pipe jacking, after the first pipe section 2-2 is jacked upwards, a new pipe section is spliced ​​to the tail end of the first pipe section 2-2, and the tail end of the first pipe section 2-2 is welded to the top end of the new pipe section. Subsequently, after each pipe section is jacked up a certain distance, another new pipe section is spliced ​​to the tail end of the new pipe section and welded in place.

[0072] During the upward construction of the pipe jacking, the first pipe section 2-2 always follows the tail of the pipe jacking machine head. The circumferential joints between every two pipe sections are firmly welded with bevel welds until the first pipe section 2-2 is lifted to the bottom plate of the ventilation shaft. Then, the pipe jacking machine head 5-5 is removed, and the top of the first pipe section 2-2 is connected and fixed to the pipe receiving hole of the ventilation shaft to complete the construction of the vertical ventilation duct 2-1. Finally, the last pipe section 2-3 of the ventilation duct is welded and fixed to the shield tunnel.

[0073] The present invention also provides a ventilation shaft structure, including a main structure located on the first underground floor and a vertical ventilation duct 2-1 connected to the tunnel; the tunnel includes a left tunnel 3 and a right tunnel 4, which are arranged parallel to each other and extend horizontally at both ends in the longitudinal direction; the trains in the left tunnel 3 and the right tunnel 4 have opposite directions; the direction of oncoming trains is forward and the direction of departure is backward; the left tunnel 3 and the right tunnel 4 are each provided with two or more pipe jacking starting holes.

[0074] The main structure is a cuboid structure, including a staircase area and a ventilation area arranged side by side. The top plate of the ventilation area is equipped with two piston air shaft valves, which are set diagonally. The bottom plate of the ventilation area has two or more jacking pipe receiving holes on each side. Jacking pipe receiving hole ring beams 1-9 are provided at the jacking pipe receiving holes. The first jacking pipe section 2-2 of the air duct is set in the jacking pipe receiving hole. A horizontal air valve 6-6 wall is arranged at the upper end of the first jacking pipe section 2-2.

[0075] A vertical air valve 6-5 is installed between each pair of jacking pipe receiving holes on the right side of the base plate, and a vertical air valve 6-5 is also installed between each pair of jacking pipe receiving holes on the left side of the base plate; a fan is installed between the jacking pipe receiving holes on the right side of the base plate and the jacking pipe receiving holes on the left side of the base plate at the same horizontal position, and a vertical air valve 6-5 is installed at each end of the fan.

[0076] The vertical centerline of each jacking starting hole is aligned and coincides with the vertical centerline of a jacking receiving hole; each jacking receiving hole is connected to the jacking starting hole of the tunnel through a ventilation duct.

[0077] The main structure has a stairwell at the corner where the piston air shaft and air valve are located, and there is a partition wall between the stairwell and the adjacent piston air shaft and air valve.

[0078] In this embodiment, the jacking pipe receiving hole ring beams 1-9 are square structures.

[0079] In this embodiment, a stairwell is provided on one side of the stairwell area, which extends upward to above the ground and has a work room 1-13 at its top, which is located above the ground.

[0080] In this embodiment, a partition wall is provided between the stair area and the ventilation area to separate the ventilation area and the stair area. A gap or opening is provided in the middle of the partition wall, mainly to connect the stair area and the ventilation area, so as to facilitate the entry and exit of staff.

[0081] In this embodiment, the piston ventilation shaft extends upward to above ground level, and a ventilation pavilion 1-14 is provided at its top above ground level.

[0082] The above technical solution mainly achieves the following effects:

[0083] First, the vertical pipe jacking technology for constructing vertical ventilation ducts allows for independent construction of the shield tunnel and the ventilation shafts within the tunnel sections, with no inter-tapering in their construction schedules. This changes the existing technology's requirement to construct the ventilation shaft structure first, followed by shield tunneling, eliminating the constraint of ventilation shaft construction progress on shield tunneling progress and making the scheduling of ventilation shaft and shield tunneling more flexible and efficient. Second, compared to existing technologies with two or more underground ventilation shaft structures, this patent uses a single-level underground ventilation shaft structure, reducing the excavation depth, lowering the risk of excavation, reducing the scale of excavation earthwork, retaining structures, and the main ventilation shaft structure, shortening the construction period, and significantly reducing project investment. Third, the ventilation duct constructed using the vertical pipe jacking mechanical method provided in this patent… The small size of a single ventilation duct jacking pipe reduces construction difficulty, meeting the ventilation requirements of the tunnel section. Furthermore, the mechanical jacking process ensures efficient and safe construction, significantly reducing the impact on the surrounding environment and further promoting high-quality, green construction. Fourth, this patented technology solves the problem of mutual constraints between the longitudinal slope design of the line and the site selection of the ventilation shaft. The excavation depth of the ventilation shaft pit no longer needs to be increased due to the burial depth of the line, and the longitudinal profile design of the line is no longer limited by the site selection conditions of the ventilation shaft. Therefore, the longitudinal slope of the line can adopt the optimal solution, and the ventilation shaft can be selected at a location with less impact on the surrounding environment and less difficulty in project implementation, reducing the difficulty of project implementation, construction risks, and project investment, achieving the goals of resource conservation and environmental protection.

[0084] Example 2

[0085] This embodiment also discloses a ventilation shaft structure, such as Figures 2-6 As shown, it includes the main structure located on the first basement level and the vertical ventilation duct 2-1 connected to the tunnel;

[0086] The tunnel includes a left tunnel 3 and a right tunnel 4. Each of the left tunnel 3 and the right tunnel 4 has two pipe jacking starting holes. The first and second pipe jacking starting holes are located in the right tunnel 4, and the third and fourth pipe jacking starting holes are located in the left tunnel 3. The first and second pipe jacking starting holes are arranged one after the other. The third and fourth pipe jacking starting holes are arranged one after the other.

[0087] The main structure is a cuboid structure, also including a ventilation area and a staircase area. The top plate of the ventilation area is equipped with two piston air shaft valves, which are diagonally arranged. Above the piston air shaft valves are piston air shaft sidewalls 1-2, with the first piston air shaft 1-4 valve located in the lower left corner and the second piston air shaft 1-6 valve located in the upper right corner. The bottom plate of the ventilation area has two jacking pipe receiving holes on each side, and a jacking pipe receiving hole ring beam 1-9 is provided at the jacking pipe receiving hole. Preferably, the jacking pipe receiving hole ring beam 1-9 is a square structure. The first jacking pipe section 2-2 of the air duct is set inside the jacking pipe receiving hole. A horizontal air valve 6-6 is arranged at the upper end of the first jacking pipe section 2-2.

[0088] The first and second jacking pipe receiving holes are located on the right side of the base plate, and the third and fourth jacking pipe receiving holes are located on the left side of the base plate. The first and second jacking pipe receiving holes are arranged one after the other, and the third and fourth jacking pipe receiving holes are also arranged one after the other. A first vertical air valve 6-5 is installed between the first and second jacking pipe receiving holes and between the third and fourth jacking pipe receiving holes. A first fan 6-3 is installed between the first and third jacking pipe receiving holes, and a second fan 6-4 is installed between the second and fourth jacking pipe receiving holes. A second vertical air valve 6-5 is installed at both ends of the first fan 6-3 and the second fan 6-4.

[0089] The vertical center lines of the first to the fourth jacking pipe starting holes are aligned and coincide with the vertical center lines of the first to the fourth jacking pipe receiving holes, respectively; each jacking pipe receiving hole is connected to the tunnel through the jacking pipe starting hole.

[0090] A stairwell is located at the corner of the main structure where the piston ventilation shaft and air valve are located. A partition wall separates the stairwell from the adjacent piston ventilation shaft and air valve. The stairwell extends upwards to above ground level, and a work area 1-13 is located at its top, above ground level. The piston ventilation shaft also extends upwards to above ground level, and a ventilation pavilion 1-14 is located at its top, above ground level. Work areas 1-13 and ventilation pavilions 1-14 are adjacent to each other and have the same height.

[0091] In another embodiment, the construction method of the subway section ventilation shaft structure includes the following specific steps:

[0092] S1, Determining the construction location: Based on the project plan and site conditions, determine the construction location of the ventilation shaft in the section;

[0093] S2, Construction of retaining structure, foundation pit and external overall structure of the interval ventilation shaft: After the construction of the retaining structure 1-8 of the interval ventilation shaft foundation pit according to the construction location, the foundation pit is excavated, and then the main structure of the underground floor and the ground structure of the interval ventilation shaft are constructed, and the piston ventilation shaft is constructed on the top plate of the interval ventilation shaft.

[0094] S3, Shield tunnel construction: While constructing the ventilation shaft in the section, tunnel construction is carried out below the ventilation shaft using shield tunneling.

[0095] During tunnel construction, the two rings before and after the tunnel interface with the vertical ventilation duct 2-1, i.e., the pipe sections used to set the starting holes for pipe jacking, are made of steel pipe segments. The starting hole reserved at the top of the tunnel steel pipe segments is divided into reinforced concrete pipe segments 4-2, in which the reinforcing bars are glass fiber bars 4-4 that can be cut by the pipe jacking tool. The two ends of the glass fiber bars 4-4 pass through the perforations in the starting hole wall at the top of the steel pipe segments. The remaining sections of the tunnel are made of reinforced concrete pipe segments 4-2.

[0096] S4, Construction of vertical ventilation duct 2-1 between the inter-section ventilation shaft and the shield tunnel;

[0097] Before the pipe jacking operation, the pipe jacking machine 5-5 is installed directly below the starting hole of the air duct pipe jacking. Before installing the pipe jacking machine 5-5, a lifting base 5-10 is first set at the bottom of the tunnel directly below the corresponding air duct installation position to provide the pipe jacking propulsion reaction force. Above the lifting base 5-10 is the pipe jacking operation platform. Four lifting cylinders are evenly distributed on the pipe jacking operation platform along the plane projection of the pipe wall. A ring-shaped jacking iron 5-7 is placed on the top surface of the lifting cylinder to provide a uniform lifting thrust to the pipe section.

[0098] Specifically, at the starting hole of the jacking pipe, two layers of water-stopping rubber rings are installed on the contact surface between the steel pipe segment and the concrete pipe segment 4-3. The top steel pipe segment cavity within a certain range of the outer wall of the starting ring, mainly the connection section between the concrete pipe segment 4-3 and the steel pipe segment, is filled with micro-expansion concrete. After the steel pipe segments are assembled, the jacking pipe starting ring 5-1 is installed on the top. The top surface of the starting ring is curved and welded tightly to the inner wall of the steel pipe segment. Triangular reinforcing ribs 5-2 are welded at the interface between the jacking pipe starting ring 5-1 and the steel pipe segment. Two sealing water-stopping brushes are installed along the circumferential direction on the lower inner wall of the jacking pipe starting ring 5-1. The first sealing water-stopping brush is located above the first sealing water-stopping brush and plays a role in sealing water during the jacking pipe starting and lifting construction.

[0099] After the pipe jacking machine 5-5 is installed, the first pipe section 2-2 of the vertical air duct 2-1 is spliced ​​on the pipe jacking machine 5-5. Through the action of the lifting cylinder 5-8 of the pipe jacking machine 5-5, the head of the pipe jacking machine 5-5 is lifted into the starting collar, so that the two circumferential sealing water-stop brushes of the pipe jacking machine 5-5 are in close contact with the outer wall of the pipe jacking equipment head.

[0100] During the jacking operation, it is necessary to ensure that the centerline of the jacking starting hole and the centerline of the jacking receiving hole are always aligned and coincident. Before the first jacking pipe section 2-2 is jacked to the jacking receiving hole, the jacking receiving hole is temporarily sealed by the jacking receiving hole concrete cushion layer 1-15.

[0101] In this embodiment, to facilitate understanding of the technical solution, the pipe jacking operations above the left tunnel and the right tunnel are carried out separately. In actual operation, the ventilation duct construction of the left and right tunnels can be carried out simultaneously or separately depending on factors such as construction period, environment, and cost, in order to shorten the construction period and save costs.

[0102] In this embodiment, the lower end of each vertical ventilation duct 2-1 is connected to the pre-reserved jacking starting hole at the top of the tunnel, and its upper end is connected to the bottom plate of the ventilation area. The overall height of each vertical ventilation duct 2-1 is the vertical distance between the top of the tunnel and the bottom of the ventilation shaft bottom plate 1-3. The vertical ventilation duct 2-1 structure is constructed using pipe jacking technology. The pipe sections are made of steel with an outer diameter D = 2m and an inner diameter d = D - 2t, where t is the steel pipe wall thickness, t = t0 + t1, t0 is the calculated thickness required for structural load-bearing, and t1 is the calculated thickness for corrosion during the structure's service life. Each pipe section is 1m long, and the sections are joined by bevel welding.

[0103] S5, carry out the connection and fixing of the first jacking pipe section to the basement floor slab and the water-stopping construction at the joint; and permanently seal the joint between the first jacking pipe section 2-2 of the vertical air duct 2-1 and the base slab of the inter-section air shaft.

[0104] The water-stopping construction method is as follows:

[0105] S501, When constructing the base plate, L-shaped steel plates 7 are pre-embedded along the inner perimeter of the ring beam 1-9 of the jacking pipe receiving hole, in order to facilitate welding with the first jacking pipe section 2-2;

[0106] S502 After receiving the first jacking pipe section 2-2, a temporary grouting pipe 7-1 is inserted into the gap between the jacking pipe receiving hole ring beam 1-9 and the first jacking pipe section 2-2 to grout and stop water at the interface between the bottom of the base plate and the outer wall of the first jacking pipe section 2-2.

[0107] S503 After grouting is completed, micro-expansion concrete 4-5 is filled in the gap between the receiving hole ring beam 1-9 of the jacking pipe and the first jacking pipe section 2-2 to fill the gap tightly and at the same time play a role in water stop.

[0108] S504, such as Figure 10-11 By fixing steel plate 7-3, the pre-embedded L-shaped steel plate 7 of the jacking pipe receiving hole ring beam 1-9 is welded and fixed to the outer wall of the first jacking pipe section 2-2, so as to fix the pipe section and seal the water, thereby achieving the purpose of fixing and permanent water sealing.

[0109] S6, Construction of the internal structure of the ventilation shaft: Installation of the horizontal air valve 6-6 wall, the vertical air valve 6-5 wall, and stairwells 1-12 inside the ventilation shaft, and installation of the first fan 6-3, the second fan 6-4, and each horizontal air valve 6-6 and vertical air valve 6-5.

[0110] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A mechanical method for constructing ventilation shafts, characterized in that, Specifically, the following steps are included: S1, Determine the construction location of the underground basement structure: Based on the project plan and site conditions, determine the construction location of the ventilation shaft in the section; S2, Construction of retaining structure, foundation pit and external overall structure of the interval ventilation shaft: After the retaining structure of the interval ventilation shaft foundation pit is constructed according to the construction location, the foundation pit is excavated, and then the main structure of the underground floor and the ground structure of the interval ventilation shaft are constructed, and the piston ventilation shaft is constructed on the top plate of the interval ventilation shaft. S3, Shield tunnel construction: While the ventilation shaft of the section is being constructed, a shield tunnel is being constructed below the ventilation shaft by shield excavation. S4, construct the vertical ventilation duct between the ventilation shaft and the shield tunnel; construct the jacking starting hole of the ventilation duct at the top of the shield tunnel, and carry out the jacking operation until it reaches the jacking receiving hole of the bottom plate of the ventilation shaft, thus completing the construction of the vertical ventilation duct. S5, Connect and fix the first jacking pipe section to the bottom plate of the interval ventilation shaft and perform water-stopping construction at the joint: Weld and fix the first jacking pipe section to the bottom plate of the interval ventilation shaft, and permanently seal the joint between the first jacking pipe section of the vertical air duct and the bottom plate of the interval ventilation shaft. S6, Construction of the internal structure of the ventilation shaft: Installation of horizontal and vertical air valve walls and stairwells inside the ventilation shaft, and installation of fans and various air valves.

2. The mechanical method for constructing a ventilation shaft as described in claim 1, characterized in that, In S3, the pipe segment used to set the jacking starting hole of the shield tunnel is made of composite steel pipe segment, and the remaining sections of the shield tunnel are made of full-ring reinforced concrete pipe segment.

3. The mechanical method for constructing a ventilation shaft as described in claim 1, characterized in that, In step S4, the centerline of the jacking pipe starting hole is aligned and coincides with the centerline of the jacking pipe receiving hole.

4. The mechanical method for constructing a ventilation shaft as described in claim 1, characterized in that, In step S4, before the pipe jacking operation is carried out, a pipe jacking machine is installed directly below the starting hole of the air duct pipe jacking, and the first pipe section of the air duct is spliced ​​and fixed. Through the action of the lifting cylinder of the pipe jacking machine, the pipe jacking machine head is lifted into the starting collar, so that the two circumferential sealing water-stop brushes of the pipe jacking machine are in close contact with the outer wall of the pipe jacking equipment head.

5. The mechanical method for constructing a ventilation shaft as described in claim 4, characterized in that, In step S4, the first jacking pipe section is fixedly connected to the tail end of the jacking machine. During the vertical jacking operation, after the first jacking pipe section is lifted one section upwards, a new pipe section is spliced ​​below it. After each section is lifted, a new pipe section is spliced. The circumferential joint between each two pipe sections is firmly welded with bevel welds until the first jacking pipe section is lifted to the bottom plate of the ventilation shaft. Then, the head of the jacking machine is removed, and the top of the first jacking pipe section is connected to the jacking receiving hole of the ventilation shaft to complete the construction of the vertical ventilation duct. Finally, the last jacking pipe section of the ventilation duct is welded and fixed to the shield tunnel.

6. A ventilation shaft structure, characterized in that, It is obtained by the mechanical ventilation shaft construction method according to any one of claims 1-5, which includes a main structure located on the first underground floor and a vertical ventilation duct connected to the tunnel; The tunnel includes a left tunnel and a right tunnel, which are arranged parallel to each other and extend horizontally at both ends. Trains in the left tunnel and the right tunnel travel in opposite directions, with the oncoming trains going forward and the departing trains going backward. Each of the left tunnel and the right tunnel is provided with two or more pipe jacking starting holes. The main structure is a cuboid structure, including a staircase area and a ventilation area arranged side by side. The top plate of the ventilation area is equipped with two piston air shaft valves, which are arranged diagonally. The bottom plate of the ventilation area has two or more jacking pipe receiving holes on each side. A jacking pipe receiving hole ring beam is provided at each jacking pipe receiving hole. The first jacking pipe section of the air duct is installed in the jacking pipe receiving hole. A horizontal air valve wall is provided at the upper end of the first jacking pipe section. A vertical air valve is provided between each pair of the jacking pipe receiving holes on the right side of the base plate, and a vertical air valve is also provided between each pair of the jacking pipe receiving holes on the left side of the base plate; a fan is provided between the jacking pipe receiving holes on the right side of the base plate and the jacking pipe receiving holes on the left side of the base plate at the same horizontal position, and a vertical air valve is provided at each end of the fan. The vertical centerline of each of the pipe jacking starting holes is aligned and coincides with the vertical centerline of a pipe jacking receiving hole; each of the pipe jacking receiving holes is connected to the pipe jacking starting hole of the tunnel through a ventilation duct. A stairwell is located at the corner of the main structure where the piston air shaft and air valve are located, and a partition wall is provided between the stairwell and the adjacent piston air shaft and air valve.

7. A ventilation shaft structure as described in claim 6, characterized in that, The ring beam of the jacking pipe receiving hole has a square structure.

8. A ventilation shaft structure as described in claim 6, characterized in that, A stairwell is provided on one side of the stairwell area, which extends upward to above ground level, and a workroom is provided on its top, which is located above ground level.

9. A ventilation shaft structure as described in claim 6, characterized in that, A partition wall is provided between the staircase area and the ventilation area.

10. A ventilation shaft structure as described in claim 6, characterized in that, The piston ventilation shaft valve extends upwards to above ground level, and a ventilation pavilion is installed at its top above ground level.

Images