An assembled anti-floating subway station using the pipe jacking method

Abstract

The present invention discloses a pipe-jacking method assembled anti-floating subway station, which includes a reinforced soil mass and a box body. The box bodies are symmetrically arranged along the reinforced soil mass. The box body is alternately spliced by a first component and a second component. A connection port is provided on the second component, and a channel strengthening steel-concrete frame is fixedly arranged along the inner circumference of the connection port. The positions of the connection ports on the box bodies on both sides of the reinforced soil mass are opposite. A connection channel is also arranged between the two box bodies, and the two ends of the connection channel are fixedly connected to the channel strengthening steel-concrete frame. Anti-pulling piles are arranged in the reinforced soil mass below the connection channel, and the tops of the anti-pulling piles are fixedly connected to the bottom of the connection channel. The construction method of this pipe-jacking method assembled subway station does not require the traditional foundation pit enclosure structure + support system, does not excavate the road surface, does not close the traffic, does not relocate pipelines, and has a small floor area. It can meet the anti-floating requirements of subway stations in water-rich soft soil areas, make up for the technical shortcomings of mined assembled stations, and reduce the construction safety risks of underground projects.

Description

Technical Field

[0001] The invention belongs to the technical field of underground structures and construction, and particularly relates to a pipe-jacking method assembled anti-floating subway station. Background Art

[0002] With the expansion of cities and the growth of the population, the urban subway network is becoming increasingly dense, and the construction pace urgently needs to be accelerated. The precast and assembled technology, as an industrialized construction mode for underground structures, has significant advantages in improving project quality, accelerating construction speed, reducing floor area, saving materials, saving labor, and being environmentally friendly and low-carbon, meeting the national policy orientation and strategic needs. Currently, precast and assembled subway stations have been implemented in China, and the construction of subway stations generally includes the open-cut method and the mined method. When using the open-cut method for construction, it generally occupies roads and affects residents' travel. Coupled with pipeline relocations, etc., the social and economic benefits are not significant; when using the mined method for construction, there is no need for traditional foundation pit retaining structures and support systems, and construction can be carried out without excavating the road surface, closing traffic, or relocating pipelines. However, since the overburden soil on the top of the subway station is generally shallow, in water-rich soft soil areas, the open-cut method stations generally use diaphragm walls combined with capping beams to achieve the anti-floating of the subway station. Currently, the anti-floating construction of mined method stations is more difficult. Therefore, it is necessary for us to design a pipe-jacking method assembled anti-floating subway station to solve these problems. Summary of the Invention

[0003] The problem to be solved by the invention is to provide a pipe-jacking method assembled anti-floating subway station for anti-floating construction of underground spaces using the mined method.

[0004] To solve the above technical problems, the technical solution adopted by the invention is as follows:

[0005] A pipe-jacking method assembled anti-floating subway station includes a reinforced soil mass and a box body. The box body is symmetrically arranged along the reinforced soil mass. The box body is alternately spliced by a first component and a second component. A connection port is provided on the second component, and a channel strengthening reinforced concrete frame is fixedly arranged along the inner circumference of the connection port. The positions of the connection ports on the box bodies on both sides of the reinforced soil mass are opposite. A connection channel is further arranged between the two box bodies, and both ends of the connection channel are fixedly connected to the channel strengthening reinforced concrete frame. Anti-pulling piles are arranged in the reinforced soil mass below the connection channel, and the tops of the anti-pulling piles are fixedly connected to the bottom of the connection channel.

[0006] Preferably, the first component is composed of a number of first splicing rings spliced together, and the second component is composed of a number of second splicing rings spliced together. On one end face of the first splicing ring and the second splicing ring, there are limiting protrusions, and on the other end face, there are limiting grooves. The limiting protrusions and the limiting grooves cooperate with each other. A number of prestressed tendons are arranged on the first component and the second component along the extending direction of the box body.

[0007] With such a setting, the assembled design reduces the construction difficulty, and the prestressed tendons can effectively complete the lateral fixation of the box body.

[0008] Preferably, the first splicing ring is formed by enclosing a top plate precast block, a bottom plate precast block and two side wall precast blocks. There are corbel structures on the side wall precast blocks, and a middle plate precast block is arranged in the first splicing ring through the corbel structures.

[0009] Preferably, the second component is composed of a number of second splicing rings spliced together. The second splicing ring is formed by enclosing a top plate precast block, a side wall precast block, a bottom plate precast block and two connection precast blocks. There is a break between the two connection precast blocks. The breaks on a number of the second splicing rings are connected to form a connection opening on the second component. A corbel precast block is arranged in the middle of the break and between the two connection precast blocks. The corbel precast block divides the connection opening into upper and lower parts. There are corbel structures on the side wall precast blocks, and a middle plate precast block is fixedly connected to the corbel structure. The other end of the middle plate precast block is connected to the corbel precast block.

[0010] With such a setting, the on-site workload and construction complexity can be reduced, and the construction efficiency and project quality can be improved.

[0011] Preferably, the channel strengthening reinforced concrete frames can be independently arranged above and / or below the corbel precast block that divides the connection opening into two parts.

[0012] With such a setting, it can not only reinforce the connection opening but also support the corbel precast block and the middle plate, making the whole more stable and firm.

[0013] Preferably, the connection channel includes a channel top plate, a channel bottom plate, a channel middle plate and channel side walls. The channel bottom plate and the channel middle plate are both fixedly connected to the channel strengthening reinforced concrete frame below the corbel precast block. The channel top plate is fixedly connected to the channel strengthening reinforced concrete frame above the corbel precast block. The channel side walls are fixedly connected to the channel strengthening reinforced concrete frame above and / or below the corbel precast block.

[0014] With such a setting, it can complete the connection of the box body, and at the same time, the combination with the anti-pulling piles at the bottom and the channel strengthening reinforced concrete frame can effectively meet the anti-floating requirements.

[0015] Preferably, the precast blocks surrounding the first splicing ring and the second splicing ring cooperate with each other by arranging a concave-convex tenon structure.

[0016] With this arrangement, the shear resistance between the precast blocks is improved, preventing the splicing ring from losing its capacity due to excessive pressure.

[0017] Preferably, epoxy resin glue is applied at the joints of the precast blocks surrounding the first splicing ring and the second splicing ring and bolt connections are used. The middle plate precast blocks inside the first splicing ring and the second splicing ring are respectively fixed by anchor bolts, and fine-grained concrete is poured into the gaps.

[0018] With this arrangement, the sealing performance of the box body is improved, preventing water leakage at the joints.

[0019] The advantages and positive effects of the present invention are:

[0020] 1. It can meet the anti-floating requirements of subway stations in water-rich soft soil areas, overcome the problem of insufficient anti-floating capacity of traditional mined stations due to shallow topsoil coverage, and make up for the technical shortcomings of mined precast stations.

[0021] 2. By using the pipe jacking method, there is no need for traditional foundation pit retaining structures + support systems, no road excavation, no traffic closure, no pipeline relocation, small floor area, and little impact on traffic.

[0022] 3. Moreover, the concrete quality of precast and assembled components is controllable, can be mass-produced, has uniform quality, high construction accuracy, and short construction period, which can greatly shorten the construction period and reduce the construction safety risks of underground projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 is the plan layout diagram of the subway station of the present invention;

[0025] Figure 2 is the cross-sectional view of the first splicing ring of the present invention at the B-B position;

[0026] Figure 3 is the cross-sectional view of the second splicing ring of the present invention at the C-C position during the jacking construction stage;

[0027] Figure 4 It is a schematic cross-sectional view at the C-C position after the construction of the connection channel of the second splicing ring of the present invention;

[0028] Figure 5 It is during the jacking construction stage of the present invention Figure 3 and is a schematic cross-sectional view at the A-A position;

[0029] Figure 6 It is a schematic cross-sectional view after the construction of the connection channel of the present invention;

[0030] Figure 7 It is a schematic horizontal cross-sectional view of the side wall precast block at the D-D position after the tensioning of the prestressed tendon of the present invention;

[0031] Figure 8 It is Figure 4 an enlarged schematic view of the concave-convex tenon structure at the H position.

[0032] The description of the reference numerals is as follows:

[0033] 1. Box body; 2. Reinforced soil mass; 3. Uplift resistance pile; 4. First splicing ring; 5. Second splicing ring; 6. Steel section combination structure; 7. End head shaft; 8. Roof precast block; 9. Floor precast block; 10. Side wall precast block; 11. Middle plate precast block; 12. Connection precast block; 13. Corbel precast block; 14. Corbel structure; 15. Station hall frame; 16. Platform frame; 17. Channel roof; 18. Channel middle plate; 19. Channel floor; 20. Channel side wall; 21. Limit protrusion; 22. Limit groove; 23. Concave-convex tenon structure; 24. Prestressed tendon; 25. Uplift resistance area; 26. Spacing area. Detailed implementation manners

[0034] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0035] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] The present invention will be further described below with reference to the accompanying drawings:

[0037] Embodiment 1

[0038] As Figures 1-8 shown, a jacking method assembled anti-floating subway station includes a reinforced soil mass 2 and a box body 1. The box body 1 is symmetrically arranged along the reinforced soil mass 2. The box body 1 is alternately spliced by a first component and a second component. A connection port is provided on the second component, and a channel strengthening reinforced concrete frame is fixedly arranged along the inner circumference of the connection port. The positions of the connection ports on the box bodies 1 on both sides of the reinforced soil mass 2 are opposite. A connection channel is also provided between the two box bodies 1. The two ends of the connection channel are fixedly connected to the channel strengthening reinforced concrete frame. Anti-pulling piles 3 are arranged in the reinforced soil mass 2 below the connection channel, and the tops of the anti-pulling piles 3 are fixedly connected to the bottom of the connection channel.

[0039] As Figure 2 、 6 、7 shown, the first component is spliced by a plurality of first splicing rings 4, and the second component is spliced by a plurality of second splicing rings 5. Limiting protrusions 21 are arranged on one end surface of the first splicing ring 4 and the second splicing ring 5, and limiting grooves 22 are arranged on the other end surface. The limiting protrusions 21 and the limiting grooves 22 cooperate with each other. A plurality of prestressing tendons 24 are arranged on the first component and the second component along the extending direction of the box body 1. With such a splicing design, the construction difficulty is reduced, and the prestressing tendons 24 can effectively complete the lateral fixation of the box body 1.

[0040] As Figure 2 、 3As shown in the figure, the first splicing ring 4 is formed by enclosing a top plate precast block 8, a bottom plate precast block 9, and two side wall precast blocks 10. A corbel structure 14 is provided on the side wall precast block 10. Inside the first splicing ring 4, a middle plate precast block 11 is arranged through the corbel structure 14. The second component is composed of a number of second splicing rings 5 spliced together. The second splicing ring 5 is formed by enclosing a top plate precast block 8, a side wall precast block 10, a bottom plate precast block 9, and two connecting precast blocks 12. A break is provided between the two connecting precast blocks 12. The breaks on a number of second splicing rings 5 are connected to form a connection port on the second component. A corbel precast block 13 is arranged in the middle of the break and between the two connecting precast blocks 12. The corbel precast block 13 divides the connection port into upper and lower parts. A corbel structure 14 is provided on the side wall precast block 10. The middle plate precast block 11 is fixedly connected to the corbel structure 14, and the other end of the middle plate precast block 11 is connected to the corbel precast block 13. With such a setting, the on-site workload and construction complexity can be reduced, and the construction efficiency and project quality can be improved.

[0041] As Figure 6 shown, a channel strengthening reinforced concrete frame can be independently arranged above and / or below the corbel precast block 13 that divides the connection port into two parts. With such a setting, the connection port can be strengthened and the corbel precast block 13 and the middle plate can be supported, making the whole more stable and firm.

[0042] As Figure 4 shown, the connecting channel includes a channel top plate 17, a channel bottom plate 19, a channel middle plate 18, and a channel side wall 20. The channel bottom plate 19 and the channel middle plate 18 are both fixedly connected to the channel strengthening reinforced concrete frame below the corbel precast block 13. The channel top plate 17 is fixedly connected to the channel strengthening reinforced concrete frame above the corbel precast block 13. The channel side wall 20 is fixedly connected to the channel strengthening reinforced concrete frame above and / or below the corbel precast block 13. With such a setting, the connection of the box body 1 can be completed, and at the same time, the combination with the uplift resistance piles 3 at the bottom and the channel strengthening reinforced concrete frame can effectively meet the anti-floating requirements.

[0043] As Figure 8 shown, the precast blocks that enclose the first splicing ring 4 and the second splicing ring 5 are mutually matched by setting a concave-convex tenon structure 23. With such a setting, the anti-shear ability between the precast blocks is improved, and the splicing ring is prevented from losing its ability due to excessive pressure.

[0044] Epoxy resin glue is smeared at the joints of the precast blocks that enclose the first splicing ring 4 and the second splicing ring 5 and bolt connections are used. The middle plate precast blocks 11 inside the first splicing ring 4 and the second splicing ring 5 are respectively fixed by anchor bolt connections, and fine-grained concrete is poured into the gaps. With such a setting, the sealing performance of the box body 1 is improved, and water leakage at the joints is prevented.

[0045] Working process of this embodiment: First, construct end wells 7 on the ground at both ends of the required construction location. Vertically excavate the two end wells 7 to the corresponding depth, then conduct surveying and setting out on the ground between the two end wells 7. Then, adopt the RJP ultra-high pressure jet grouting method (RJP (Rodin Jet Pile) high-pressure jet grouting method on the ground according to the marked positions after setting out. The RJP method uses the kinetic energy of the ultra-high pressure jet fluid to destroy the tissue structure of the foundation, and then mixes and stirs these destroyed soil particles and hardening materials to form large-diameter pile bodies), or adopt the horizontal MJS method (MJS method: all-round high-pressure jet method (Metro Jet System) from within the two end wells 7. The MJS method can be constructed in horizontal, inclined, vertical directions, and at any angle. In this invention, horizontal angle construction is adopted) to reinforce the soil between the two end wells 7. After the reinforcement is completed, divide the reinforced soil 2 into a uplift resistance area 25 and a spacer area 26, and construct uplift resistance piles 3 in the uplift resistance area 25. The number of uplift resistance piles 3 in the uplift resistance area 25 is at least one. The length of the uplift resistance piles 3 is determined by the structure of the subway station. When the construction of the uplift resistance piles 3 is completed, assemble the precast blocks transported from the factory on the ground. Enclose a top plate precast block 8, a bottom plate precast block 9, and two side wall precast blocks 10 to form a first splicing ring 4. At the same time, apply epoxy resin glue at the joints of the top plate precast block 8, the bottom plate precast block 9, and the side wall precast blocks 10. Then, anchor and fix both ends of the middle plate precast block 11 on the corbel structures 14 of the two side wall precast blocks 10, and pour fine-grained concrete at the joints. Then, connect the limit protrusions 21 and the limit grooves 22 on the end faces of several assembled first splicing rings 4 with each other to form a first component. Then, enclose a top plate precast block 8, a side wall precast block 10, a bottom plate precast block 9, and two connection precast blocks 12 to form a second splicing ring 5, and apply epoxy resin glue at the joints of the top plate precast block 8, the bottom plate precast block 9, the side wall precast block 10, and the connection precast blocks 12. Concave-convex tenon structures 23 are provided between the precast blocks of the first splicing ring and the second splicing ring for shear resistance, and each precast block is reinforced by bolt connection. Then, install a profiled steel composite structure 6 in the fracture between the two connection precast blocks 12, and at the same time fix the corbel precast block 13 in the fracture of the second splicing ring 5 through the profiled steel composite structure 6. The profiled steel composite structure 6 can support the port between the two connection precast blocks 12, making the second splicing ring 5 have higher compressive capacity and facilitating to meet the later construction requirements. Then, anchor and connect one end of the middle plate precast block 11 with the corbel structure 14 on the side wall precast block 10, and the other end with the corbel precast block 13, and pour fine-grained concrete at the joints. Then, connect the limit protrusions on the end faces of several second splicing rings 5 with the limit grooves 22 with each other to form a second component. At the same time, the ports on several second splicing rings 5 are connected to form a connection port on the second component. Then, install a pipe jacking system in one of the end wells 7.The first and second assembly rings assembled on the ground are pushed into the two sides of the reinforced soil body 2 in sequence, and the box body 1 is formed on both sides of the reinforced soil body 2. When pushing, the connection ports on the second assembly on both sides of the reinforced soil body 2 are opposite to each other, and each second assembly on the box body after pushing corresponds to the position of the anti-pulling area 25, and the first assembly corresponds to the position of the spacing area 26. Then, the prestressed beam 24 is inserted from one end of the box body 1, and successively passes through each first assembly and second assembly constituting the box body 1, and then passes out from the other end of the box body 1, so that the prestressed beam One end of 24 is anchored on the box body 1, and then the prestressed bundle 24 is tensioned and fixed at the other end of the box body 1. After all the prestressed bundles 24 are tensioned, they are placed in the box body 1. Then, the steel composite structures 6 in the connecting ports on each second component are removed respectively, and the channel reinforcement steel-concrete frame is cast on the supporting formwork around the connecting port. Since the corbel prefabricated blocks 13 in the fracture on the second splicing ring 5 are connected, the connecting port on the second component is divided into two parts, and channel reinforcement steel-concrete frames can also be independently set above and / or below the corbel prefabricated blocks 13, such as, Figure 4 , Figure 6 The channel reinforcement steel-concrete frame separately arranged below the corbel prefabricated block 13 is the platform frame 16, which is in the shape of a Chinese character "口". The corbel prefabricated block 13 is installed on the top of the platform frame 16. The channel reinforcement steel-concrete frame separately arranged above the corbel prefabricated block 13 is the station hall frame 15, which is in the shape of a Chinese character "匚" rotated ninety degrees clockwise. Moreover, the steel bars inside the platform frame 16 and the station hall frame 15 are connected to the reserved steel bars on the connecting port, thereby ensuring the strength of the channel reinforcement steel-concrete frame. Then, the reinforced soil 2 between the connecting ports on the two adjacent second components is excavated to expose the pull-out pile 3. The pile head of the pull-out pile 3 is chiseled out to expose the steel bars inside the pull-out pile 3. Then, the template is supported between the two connecting ports to connect the channel. The steel bars at both ends are connected to the steel bars in the channel reinforcement steel-concrete frame, and the internal steel bars exposed after the heads of the pull-out piles 3 are chiseled off are connected to the steel bars at the bottom of the connecting channel. After the connection is completed, the connecting channel is poured, and then the connecting channel is constructed on the reinforced soil 2 between other connecting ports. The two boxes on both sides of the reinforced soil 2 are connected through the connecting channel, and the connecting channel is also anti-floating through the structure formed by connecting the pull-out piles 3 and the channel reinforcement steel-concrete frame, so that the box composed of the first components and the second components has a strong anti-floating ability, which prevents the box from floating due to the shallow top cover. The safety of the subway station is improved and the construction period of the subway station is shortened.

[0046] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. An assembled anti-floating subway station using the pipe jacking method, characterized in that: The invention comprises a reinforced soil body (2) and a box body (1), wherein the box body (1) is symmetrically arranged along the reinforced soil body (2), the box body (1) is formed by alternately splicing a first component and a second component, a connection port is arranged on the second component, a channel reinforcement steel-concrete frame is fixedly arranged along the inner periphery of the connection port, the connection ports on the boxes (1) on both sides of the reinforced soil body (2) are located opposite to each other, a connection channel is further arranged between the two boxes (1), both ends of the connection channel are fixedly connected to the channel reinforcement steel-concrete frame, and anti-pullout piles are arranged in the reinforced soil body (2) below the connection channel. (3), the top of the pull-out pile (3) is fixedly connected to the bottom of the connecting channel; the first component is composed of a plurality of first splicing rings (4) spliced ​​together, and the second component is composed of a plurality of second splicing rings (5) spliced ​​together, and a limiting protrusion (21) is provided on the end surface of one side of the first splicing ring (4) and the second splicing ring (5), and a limiting groove (22) is provided on the end surface of the other side, and the limiting protrusion (21) and the limiting groove (22) cooperate with each other, and a plurality of prestressed beams (24) are provided on the first component and the second component along the extension direction of the box body (1); The second component is composed of a plurality of second splicing rings (5) spliced ​​together, the second splicing ring (5) is enclosed by a top plate prefabricated block (8), a side wall prefabricated block (10), a bottom plate prefabricated block (9) and two connecting prefabricated blocks (12), a break is arranged between the two connecting prefabricated blocks (12), the breaks on the plurality of second splicing rings (5) are connected to form a connecting port on the second component, a corbel prefabricated block (13) is arranged in the middle of the break and between the two connecting prefabricated blocks (12), the corbel prefabricated block (13) divides the connecting port into two upper and lower parts, a corbel structure (14) is arranged on the side wall prefabricated block (10), a middle plate prefabricated block (11) is fixedly connected to the corbel structure (14), and the other end of the middle plate prefabricated block (11) is connected to the corbel prefabricated block (13); The channel reinforcement steel-concrete frame separately arranged below the corbel prefabricated block (13) is a platform frame (16) in the shape of a "口" character. The corbel prefabricated block (13) is installed on the top of the platform frame (16). The channel reinforcement steel-concrete frame separately arranged above the corbel prefabricated block (13) is a station hall frame (15) in the shape of a "匚" character rotated ninety degrees clockwise. In addition, the steel bars inside the platform frame (16) and the station hall frame (15) are connected to the reserved steel bars on the connection port, thereby ensuring the strength of the channel reinforcement steel-concrete frame.

2. The assembled anti-floating subway station using the pipe jacking method according to claim 1, characterized in that: The first splicing ring (4) is formed by enclosing a top plate prefabricated block (8), a bottom plate prefabricated block (9) and two side wall prefabricated blocks (10); a corbel structure (14) is arranged on the side wall prefabricated block (10); and a middle plate prefabricated block (11) is arranged in the first splicing ring (4) via the corbel structure (14).

3. The assembled anti-floating subway station using the pipe jacking method according to claim 1, characterized in that: The channel strengthening steel-concrete frame can be independently arranged above and / or below the corbel precast block (13) that divides the connection port into two parts.

4. The assembled anti-floating subway station using the pipe jacking method according to claim 3, characterized in that: The connection channel includes a channel top plate (17), a channel bottom plate (19), a channel middle plate (18) and channel side walls (20). The channel bottom plate (19) and the channel middle plate (18) are both fixedly connected to the channel strengthening steel-concrete frame below the corbel precast block (13), the channel top plate (17) is fixedly connected to the channel strengthening steel-concrete frame above the corbel precast block (13), and the channel side walls (20) are fixedly connected to the channel strengthening steel-concrete frame above and / or below the corbel precast block (13).

5. The assembled anti-floating subway station using the pipe jacking method according to claim 2, characterized in that: The precast blocks that enclose the first splicing ring (4) and the second splicing ring (5) cooperate with each other by setting a concave-convex tenon structure (23).

6. The assembled anti-floating subway station using the pipe jacking method according to claim 5, characterized in that: Epoxy resin glue is applied to the joints of the precast blocks that enclose the first splicing ring (4) and the second splicing ring (5), and bolt connections are used. The middle plate precast blocks (11) located inside the first splicing ring (4) and the second splicing ring (5) are respectively fixed by anchor bolt connections, and fine-grained concrete is poured into the gaps.

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