Prefabricated station jacking method adopting novel longitudinal beam connection

Abstract

The invention relates to the technical field of underground engineering construction, in particular to a prefabricated station jacking method using novel longitudinal beam connection, which comprises the following steps of: prefabricating prefabricated longitudinal beam single-section components according to station structure blocks, and sequentially and integrally jacking the prefabricated longitudinal beam single-section components in a ring-dividing manner under the assistance of a temporary support system; pre-stressed anchor cables are arranged in reserved anchor cable tensioning holes in the hogging moment stress areas of the prefabricated longitudinal beam single-section components in a penetrating mode and tensioned to the designed pre-stress, and the hogging moment stress areas of the prefabricated longitudinal beam single-section components form a whole; the pre-embedded stress steel plates of the prefabricated longitudinal beam single-section components of the adjacent rings are connected in the joint areas, so that the sagging moment stress areas of the multiple prefabricated longitudinal beam single-section components form a whole; and a wet joint is poured in the joint area. The method has the advantages that the construction efficiency is improved; the structural safety is enhanced; the engineering cost is reasonably controlled; the method adapts to complex geological conditions; green construction is promoted; the construction efficiency is improved, the cost is reduced, and the structural safety is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of underground engineering construction, and in particular to a prefabricated station jacking method using a novel longitudinal beam connection, which is particularly suitable for the construction of underground stations in rail transit systems such as urban subways and urban rail transit systems. Background Art

[0002] As the development of underground space in my country continues to improve, prefabricated and assembled subway stations are becoming more and more widely used, such as in the Changchun Metro prefabricated station and the Shenzhen Metro Line 12 Phase II project Shasan Station.

[0003] While pipe jacking construction technology has been widely used in various fields, including municipal pipelines and water conservancy projects, it is still in its exploratory stages for subway stations. Pipe jacking stations can be considered a special type of prefabricated subway station, capable of handling more complex surrounding environments. They are particularly advantageous when facing underground obstacles, such as overpasses and underpasses of existing structures. They can avoid or reduce large-scale ground excavation, minimizing the impact of construction on urban operations.

[0004] For example, the prefabricated stations in Changchun Metro are open-cut, two-story island platforms with single-arch, large-span structures. Therefore, their primary load-bearing form is circumferential, eliminating the need for longitudinal beams along the track and naturally eliminating longitudinal beam connection issues. China's first ultra-large-section modular rectangular pipe-jacking station was successfully completed at Shasan Station on the Shenzhen Metro Line 12 Phase II project. This station was constructed using the double-hole, close-fitting pipe-jacking method. The longitudinal beams were inserted through pre-reserved steel sockets within the prefabricated components. Later, U-shaped concrete structures were cast around the left and right longitudinal beams, creating a holistic load-bearing structure.

[0005] Overall, the application of prefabricated assembly and pipe jacking technology in subway station construction not only improves construction efficiency and project quality, but also helps reduce the impact on the environment. It is an important development direction in the field of urban rail transit construction.

[0006] However, existing pipe jacking technology still faces challenges and shortcomings during implementation. For stations constructed with rectangular cross-sections and single-tunnel jacking, longitudinal beams play a crucial role in the station structure. Due to the stress distribution of the rectangular cross-section, they cannot be eliminated. Furthermore, single-tunnel jacking cannot replicate the block-connection method used in stations with dual-tunnel jacking, leaving significant room for innovation and improvement in the connection method.

[0007] At the same time, current prefabricated stations primarily utilize open-cut excavations combined with prefabricated components. Stations typically feature horseshoe-shaped cross-sections, with the prefabricated components primarily bearing circumferential forces. The longitudinal beams along the track are also optimized accordingly, eliminating the need to consider longitudinal beam connections. However, due to construction method limitations, subway stations constructed using rectangular single-hole jacking still require longitudinal beams to bear vertical loads and maintain overall station rigidity. Traditional pipe jacking methods, more similar to open-cut prefabricated stations, do not require longitudinal component connections, necessitating a more optimized longitudinal beam connection method. Summary of the Invention

[0008] The purpose of the present invention is to solve the problems of low construction efficiency, insufficient structural safety and high cost in the prior art by providing a prefabricated station jacking method using a new type of longitudinal beam connection based on the above-mentioned shortcomings of the prior art. Through the prefabrication design of single-section components of the prefabricated longitudinal beams and the design of connection nodes, the present invention solves the problems of low construction efficiency, insufficient structural safety and high cost in the prior art.

[0009] The purpose of the present invention is achieved by the following technical solutions: A method for jacking a prefabricated station using a novel longitudinal beam connection, characterized in that it comprises the following steps: Prefabricate single-section longitudinal beam components according to the station structure. The negative bending moment stress zone of the prefabricated single-section longitudinal beam components is provided with reserved anchor cable tensioning holes. The positive bending moment stress zone of several prefabricated single-section longitudinal beam components is provided with pre-embedded stress-bearing steel plates, and joint areas are reserved on the prefabricated single-section longitudinal beam components. Building a temporary support system, the temporary support system is used to support the prefabricated longitudinal beam single section component, and with the assistance of the temporary support system, the prefabricated longitudinal beam single section component is sequentially and integrally jacked in rings; Inserting prestressed anchor cables into the reserved anchor cable tensioning holes in the negative bending moment stress zone of each prefabricated longitudinal beam single section component and tensioning them to the designed prestress, so that the negative bending moment stress zones of the plurality of prefabricated longitudinal beam single section components form a whole; Connecting the embedded stress-bearing steel plates of the adjacent rings of prefabricated longitudinal beam single-section components in the joint area, so that the positive bending moment stress-bearing areas of the plurality of the prefabricated longitudinal beam single-section components form a whole; The wet joint is cast in the joint area and the temporary support system is removed.

[0010] The prefabricated longitudinal beam single section component is a T-shaped structure. Along the connection direction of the longitudinal beam, the lower longitudinal dimension of the prefabricated longitudinal beam single section component is smaller than the upper longitudinal dimension to form a joint area, and the two side ends of the embedded stress-bearing steel plate are located in the joint area.

[0011] After the prestressed anchor cable is tensioned and anchored, grouting is performed to seal the reserved anchor cable tensioning hole.

[0012] The wet joints are made of C55 micro-expansive concrete wet joints.

[0013] Shear bolts are provided on the embedded stress-bearing steel plates.

[0014] A plurality of reserved anchor cable tensioning holes are evenly spaced in the transverse direction on the prefabricated longitudinal beam single section component, and symmetrical tensioning is adopted when the prestressed anchor cables are tensioned.

[0015] The advantages of the present invention are: 1) Improved construction efficiency: By using factory-produced prefabricated longitudinal beams and a modular temporary support system, on-site work was significantly reduced during construction, significantly improving construction speed and efficiency. The rapid assembly and connection of prefabricated components shortened the construction period of the entire station structure.

[0016] 2) Enhanced Structural Safety: Utilizing prestressing technology and a novel connection design, the load-bearing capacity of longitudinal beam connections and the overall structural rigidity are significantly enhanced. This connection method effectively resists the effects of constant live loads, such as train dynamic loads, ensuring the long-term stability and safety of the station structure. Furthermore, the introduction of a modular temporary support system ensures that longitudinal beam connections are performed under the support of the system, preventing sudden changes in the structural load system.

[0017] 3) Reasonable control of project costs: The application of prefabricated longitudinal beams and new connection systems reduces the materials and labor required for on-site construction, such as formwork, thereby facilitating more reasonable control of project costs.

[0018] 4) Adaptability to complex geological conditions: The design of the new connection node takes into account the slight uneven settlement of the foundation, and can achieve longitudinal beam connection within a certain degree of error. This flexibility and adaptability enable the present invention to perform well in different underground environments.

[0019] 5) Promoting green construction: By reducing on-site construction work and optimizing material usage, the present invention helps reduce resource consumption and waste generation during the construction process, which is in line with the concepts of green construction and sustainable development.

[0020] In summary, the present invention not only solves many problems in the prior art, but also brings about improved construction efficiency, reduced costs, and enhanced structural safety. It has significant technical advantages and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall three-dimensional structure of the present invention; Figure 2 It is a longitudinal sectional view of the present invention (connection completed state); Figure 3 It is an overall longitudinal sectional view of the present invention; Figure 4 is a cross-sectional view of the present invention; Figure 5 It is a longitudinal sectional view (detail) of the present invention. DETAILED DESCRIPTION

[0022] The features of the present invention and other related features are further described in detail below through embodiments in conjunction with the accompanying drawings to facilitate understanding by those skilled in the art: like Figure 1-5 As shown, the various marks represent: prefabricated longitudinal beam single section component 1, prestressed anchor cable 2, embedded load-bearing steel plate 3, wet joint 4, shear stud 5, structural reinforcement 6, connecting bolt 7, reserved anchor cable tensioning hole 8, temporary support system 9, and center column 10.

[0023] Example: Figures 1 to 5 As shown, a method for jacking a prefabricated station using a novel longitudinal beam connection in this embodiment includes the following steps: 1) Connection Preparation: In this embodiment, the longitudinal beam is an assembled longitudinal beam, which is composed of a number of prefabricated longitudinal beam single-section components 1. Each prefabricated longitudinal beam single-section component 1 of the longitudinal beam is a T-shaped structure. Along the connection direction (longitudinal direction) of the longitudinal beam, the lower longitudinal dimension of the prefabricated longitudinal beam single-section component is smaller than the upper longitudinal dimension to form a joint area, such as Figure 2 As shown in the figure, prestressed anchor holes 8 are installed in the negative moment-bearing areas of the precast longitudinal beam sections 1. Pre-embedded steel plates 3 and shear studs 5 are installed in the positive moment-bearing areas. The sections are prefabricated as a whole, with pre-reserved connectors, according to the station structure. After prefabrication, the sections are sequentially and integrally jacked in rings with the assistance of a temporary support system 9. This process ensures that some of the precast longitudinal beam sections 1 are positioned corresponding to the center columns 10 of the station structure, providing sufficient and stable support.

[0024] like Figure 4 As shown, in this embodiment, five reserved anchor cable tensioning holes 8 are evenly spaced laterally at the criss-crossing parts (negative bending moment stress area) of the prefabricated longitudinal beam single section component 1 of the T-shaped structure, and the five reserved anchor cable tensioning holes 8 are located above the structural steel bars 6 of the prefabricated longitudinal beam single section component 1, and the two are staggered to avoid mutual influence.

[0025] In this embodiment, both ends of the embedded stress-bearing steel plate 3 extend out of the lower structure of the prefabricated longitudinal beam single-section component 1 and have a certain upward or downward curvature to meet the docking needs with the other embedded stress-bearing steel plate on both sides thereof. At the same time, the protruding length of the embedded stress-bearing steel plate 3 is also within the range of the joint area.

[0026] 2) Connection of prestressed anchor cables 2: The prestressed anchor cables 2 are pulled through the negative bending moment area and tensioned to the designed prestress, so that the negative bending moment stress areas of several prefabricated longitudinal beam single-section components 1 form an overall stress-bearing system through the prestressed anchor cables 2.

[0027] 3) Connection of pre-embedded stress-bearing steel plates 3: Adjacent ring pre-embedded stress-bearing steel plates 3 are connected at the joint area using connecting bolts 7, so that the positive bending moment stress-bearing areas of adjacent prefabricated longitudinal beam single-section components 1 form an integral stress-bearing system through the pre-embedded stress-bearing steel plates 3.

[0028] 4) Wet joint pouring: After checking that the connection positions of all connecting bolts 7 are correct, use C55 slightly expansive concrete to pour the wet joints 4 and remove the temporary support system 9.

[0029] Although the above embodiments have described in detail the concepts and embodiments of the present invention with reference to the accompanying drawings, ordinary technicians in this field can recognize that various improvements and modifications can still be made to the present invention without departing from the scope of the claims, so they are not described in detail here.

Claims

1. A method for jacking a prefabricated station using a new type of longitudinal beam connection, characterized by: The steps include: Prefabricate single-section longitudinal beam components according to the station structure. The negative bending moment stress zone of the prefabricated single-section longitudinal beam components is provided with reserved anchor cable tensioning holes. The positive bending moment stress zone of several prefabricated single-section longitudinal beam components is provided with pre-embedded stress-bearing steel plates, and joint areas are reserved on the prefabricated single-section longitudinal beam components. Building a temporary support system, the temporary support system is used to support the prefabricated longitudinal beam single section component, and with the assistance of the temporary support system, the prefabricated longitudinal beam single section component is sequentially and integrally jacked in rings; Inserting prestressed anchor cables into the reserved anchor cable tensioning holes in the negative bending moment stress zone of each prefabricated longitudinal beam single section component and tensioning them to the designed prestress, so that the negative bending moment stress zones of the plurality of prefabricated longitudinal beam single section components form a whole; Connecting the embedded stress-bearing steel plates of the adjacent rings of prefabricated longitudinal beam single-section components in the joint area, so that the positive bending moment stress-bearing areas of the plurality of the prefabricated longitudinal beam single-section components form a whole; The wet joint is cast in the joint area and the temporary support system is removed.

2. A method for jacking a prefabricated railway station using a novel longitudinal beam connection according to claim 1, characterized in that: The prefabricated longitudinal beam single section component is a T-shaped structure. Along the connection direction of the longitudinal beam, the lower longitudinal dimension of the prefabricated longitudinal beam single section component is smaller than the upper longitudinal dimension to form a joint area, and the two side ends of the embedded stress-bearing steel plate are located in the joint area.

3. The method for jacking a prefabricated railway station using a novel longitudinal beam connection according to claim 1, characterized in that: After the prestressed anchor cable is tensioned and anchored, grouting is performed to seal the reserved anchor cable tensioning hole.

4. The method for jacking a prefabricated railway station using a novel longitudinal beam connection according to claim 1, characterized in that: The wet joints are made of C55 micro-expansive concrete wet joints.

5. The method for jacking a prefabricated railway station using a novel longitudinal beam connection according to claim 1, characterized in that: Shear bolts are arranged on the embedded stress-bearing steel plate.

6. The method for jacking a prefabricated railway station using a novel longitudinal beam connection according to claim 1, characterized in that: A plurality of reserved anchor cable tensioning holes are evenly spaced in the transverse direction on the prefabricated longitudinal beam single section component, and symmetrical tensioning is adopted when the prestressed anchor cables are tensioned.

Images