Construction method of separated island type subway platform based on mechanical small expansion and excavation section

Abstract

The application discloses a construction method of a separated island type subway platform based on a small expansion excavation section of a mechanical method, which comprises nine steps of setting a glass fiber reinforced plastic shield segment at an interface between a transverse connecting channel and a tunnel by first excavating two side main tunnels by using a shield machine, symmetrically expanding and excavating between the transverse connecting channel and the main tunnel segments to increase the platform space and improve the passenger flow and operation comfort of the separated island type station, and avoiding the defects of large construction cost of a conventional island type platform, difficulty in extending the platform and the like, and on the other hand, selecting a first line and then a station to avoid the engineering quantity and cost caused by expanding the station section (widening and deepening), and simultaneously utilizing the advantages of low disturbance and high efficiency of the shield method, so as to provide a method for constructing a subway platform.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underground structure, in particular to a construction method of island-type subway platform based on mechanical small expansion section. BACKGROUND

[0002] According to cost, building structure and passenger flow organization and other factors, subway platforms are divided into "island-type platforms" and "side-type platforms". Island-type platform, also known as central platform or central platform, is a very common subway platform. The rails are on both sides, and the platform is sandwiched in the middle, forming an "island" shape. Side-type platform, also known as side-type platform, is a platform located on one side of a railway or a highway lane. Side-type platform is the basic type of station, and island-type platform is derived from side-type platform. Relative to island-type platform, side-type platform refers to the design of rails in the center and platforms on both sides. At present, island-type platform is widely used. Due to its centralized management, it is convenient for passengers to turn back halfway. The platform utilization rate is high, and the passenger flow can be dispersed. When the up and down trains arrive at different times, they can be adjusted with each other. However, there are still some disadvantages of this method, such as high platform construction cost, difficulty in extending the platform, and the need to set up a middle station hall.

[0003] In the prior art, most subway stations are constructed by using open excavation method. The open excavation method has the advantages of high safety and relatively mature construction method. However, due to the large excavation area, the construction has a great impact on the surrounding environment, which easily causes traffic congestion. Another widely used construction method is cover excavation method, which is divided into forward method and reverse method. The difference between cover excavation forward method and open excavation method is the increase of temporary pavement cost and construction technology. Cover excavation reverse method is to construct the structure top plate in advance, and then excavate the foundation pit layer by layer under the protection of the structure top plate to construct the main foundation pit of the station. Cover excavation reverse method is suitable for the case where the temporary traffic of the pavement can be temporarily interrupted. Compared with open excavation, the impact on the pavement traffic is shorter. However, the use of open excavation method and cover excavation method with lower engineering cost has too great influence on residents, and the higher initial investment and the limitation of use determine that neither of them is a good construction method.

[0004] Shield tunneling, due to its high construction efficiency and good ground settlement control, has become the preferred method for subway tunnel construction in recent years. Shield tunneling can be divided into two methods: station-first, track-later; and track-first, station-later. In the first method, the tunnel boring machine (TBM) advances from the starting shaft of the initial station to the receiving shaft of the target station. Upon reaching the target station, it turns around or withdraws at the station's end shaft. The tunnel boring machine's passage through the station is a key technical issue, requiring the station to be constructed first using open-cut or cut-and-cover methods, serving as both the starting and receiving shafts for the TBM. Before the TBM reaches the station, the station's width and floor depth need to be appropriately increased to allow the TBM to be dragged through, accelerating the construction progress. This method minimizes interference between station construction and the TBM's tunnel construction, fully utilizing the advantages of high speed and long-distance tunneling. However, it requires enlarging the station cross-section (widening and deepening), which significantly interferes with station construction, increasing the station's workload and cost. The second method, track-first, station-later, involves constructing the shield tunnel first and then building the station. It can significantly shorten the construction cycle, improve the construction quality of subway projects, ensure safety during construction and greatly reduce the impact on the surrounding environment. Furthermore, through the long-distance application of the shield tunneling method, it can generate economies of scale and reduce the overall project cost.

[0005] Conventional shield tunnel sections are in the form of twin tunnels and twin lines, but they have problems such as small platform space on one side, poor spatial connectivity and visibility, and low user comfort. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies and incorporate the advantages of various technologies, this invention provides a construction method for a separated island subway platform based on a mechanical method with a small-scale excavation and widening section. This method employs a line-first, station-later approach, using shield tunneling to excavate both sides of the main line and then widening the transverse connecting passage at both ends to construct the subway platform. This method enables rapid, efficient, and economical construction of subway projects in complex urban environments. The invention provides the following technical solution: A construction method for a separated island subway platform based on a mechanical method with a small-scale excavation and widening section, comprising the following steps:

[0007] S1. A tunnel boring machine will be used to excavate the main tunnels on both sides first;

[0008] S2. Fiberglass reinforced shield tunnel segments are installed at the interface between the transverse connecting passage and the tunnel.

[0009] S3. After the main tunnels on both sides are completed, high-strength steel-concrete composite structure columns will be poured at the transverse connecting passage to be constructed.

[0010] S4. After completing the support of the main tunnels on both sides, remove or break the fiberglass shield tunnel segments at the interface between the transverse connecting passage and the tunnel.

[0011] S5. Transport the excavation equipment to the construction site and use mechanical methods to excavate small sections at both ends of the transverse connecting channel.

[0012] S6. Perform preliminary support and secondary lining on the excavated soil to prepare for the transverse connection channel.

[0013] S7. After the expansion excavation of the connecting channel between the two lines is completed, the excavation equipment for the connecting channel will enter the site to excavate the connecting channel between the two lines.

[0014] S8. Clean the tunnel and install platform panels;

[0015] S9. Complete the construction of the subway platform structure.

[0016] Preferably, step S1 specifically includes: using a tunnel boring machine to excavate the main subway tunnels on both sides, using a screw conveyor or belt conveyor to remove slag, and assembling the tunnel segments.

[0017] Preferably, the shield tunnel segments at the interface between the transverse connecting channel and the tunnel are prefabricated glass fiber reinforced tunnel segments.

[0018] Preferably, step S3 specifically includes: supporting the interface between the transverse connecting channel and the tunnel, using cast-in-place reinforced concrete longitudinal beams and rectangular high-strength steel pipe concrete composite structural columns, and pre-setting the column spacing, reserving steel connectors at the joint between the tunnel segment and the cast-in-place reinforced concrete beam to achieve the consolidation with the cast-in-place reinforced concrete longitudinal beam, and reserving longitudinal waterproof grooves for the shield tunnel segment.

[0019] Preferably, step S5 specifically includes: using a transverse milling head to widen the upper and lower parts of the excavation area at the connection between the main line and the transverse passage on both sides of the tunnel; replacing the excavator head with a bucket during muck removal; and transporting the muck for muck removal.

[0020] Preferably, step S6 specifically includes: performing preliminary support and secondary lining on the excavated area that has been expanded; setting up a steel arch frame installation machine, anchor drilling rig, and shotcrete robot within the preliminary support area to complete the preliminary support of the secondary lining area; then performing symmetrical secondary lining support on the secondary lining area; treating the joint between the cast-in-place concrete longitudinal beam and the cast-in-place concrete secondary lining; reserving a steel rebar connector on the joint surface of the reinforced concrete longitudinal beam; and pre-embedding a centrally embedded steel plate waterstop at the joint.

[0021] Preferably, step S7 specifically includes: after clearing the main tunnels on both sides, transporting the open-face tunneling machine to the transverse connecting passage, preparing for the construction of the connecting passage, breaking the shield segments at the symmetrical secondary lining area and the transverse connecting passage, and using the open-face tunneling machine to construct the connecting passage.

[0022] This patent proposes a construction method for a separated island subway platform based on a mechanical method with a small-scale excavation section, addressing the advantages and disadvantages of different types of subway stations, various construction methods, and specific construction procedures. By first constructing the main lines on both sides using shield tunneling, symmetrical excavation is carried out between the transverse connecting passage and the main line tunnel segments to increase platform space, improve passenger flow and operational comfort in the separated island station, and avoid the drawbacks of conventional island platform construction, such as high construction costs and difficulties in extending the platform. Furthermore, by prioritizing the line construction over the station construction, the project avoids the increased workload and costs associated with widening or deepening the station cross-section, while leveraging the low-disturbance and high-efficiency advantages of the shield tunneling method for subway platform construction.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] (1) Give full play to the safety and efficiency advantages of the shield tunneling method;

[0025] (2) Give full play to the advantages of the tunneling method and greatly reduce the impact of construction on the surrounding environment and adjacent buildings;

[0026] (3) The small cross-section expansion improves space utilization and comfort, and alleviates passenger flow pressure for stations with medium or higher passenger flow.

[0027] (4) The amount of excavation work is relatively small, which greatly reduces the risk of ground settlement control;

[0028] (5) It facilitates the rational connection of work processes and avoids mutual interference between tunnel boring and station construction. The tunnel boring machine directly tunnels through the station, avoiding auxiliary processes such as tunnel boring machine dismantling, passing through the station, or turning around. Conversely, it also avoids interference between tunnel boring machine construction and station structural construction.

[0029] (6) It is beneficial to environmental protection. Because shield tunneling is carried out first, and advanced support and stratum reinforcement are carried out before wide excavation, the disturbance to the surrounding rock is small, which is conducive to controlling the loss of stratum water and deformation of surrounding rock. The arch settlement and convergence of the platform tunnel itself are small, and the settlement of the surface and ground buildings is small. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0031] Figure 2 This is a partially enlarged schematic diagram of the joint between the shield tunnel segment, support and secondary lining of the present invention.

[0032] Figure 3 This is a schematic diagram of an excavator with a replaceable excavator head according to the present invention;

[0033] Figure 4 This is a schematic diagram of the construction steps for the upper part of the excavation zone according to the present invention;

[0034] Figure 5 This is a schematic diagram of the construction steps for the lower part of the excavation zone in this invention;

[0035] In the diagram: 1. Shield excavation area; 2. Widening excavation area; 3. Lateral connecting passage area; 4. Secondary lining area; 5. Precast glass fiber reinforced pipe segment; 6. High-strength steel pipe concrete composite structural column; 7. Shield segment; 8. Platform slab; 9. Joint between segment and cast-in-place reinforced concrete beam; 10. Joint between cast-in-place concrete longitudinal beam and cast-in-place concrete secondary lining. Detailed Implementation

[0036] 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.

[0037] This invention provides a technical solution: a construction method for a separated island subway platform based on a small-section excavation using mechanical methods, comprising the following steps:

[0038] S1. A tunnel boring machine will be used to excavate the main tunnels on both sides first;

[0039] S2. Fiberglass reinforced shield tunnel segments are installed at the interface between the transverse connecting passage and the tunnel.

[0040] S3. After the main tunnels on both sides are completed, high-strength steel-concrete composite structure columns will be poured at the transverse connecting passage to be constructed.

[0041] S4. After completing the support of the main tunnels on both sides, remove or break the fiberglass shield tunnel segments at the interface between the transverse connecting passage and the tunnel.

[0042] S5. Transport the excavation equipment to the construction site and use mechanical methods to excavate small sections at both ends of the transverse connecting channel.

[0043] S6. Perform preliminary support and secondary lining on the excavated soil to prepare for the transverse connection channel.

[0044] S7. After the expansion excavation of the connecting channel between the two lines is completed, the excavation equipment for the connecting channel will enter the site to excavate the connecting channel between the two lines.

[0045] S8. Clean the tunnel and install platform panels;

[0046] S9. Complete the construction of the subway platform structure.

[0047] As a preferred embodiment of the present invention, step S1 specifically includes: using a tunnel boring machine to complete the excavation of the subway mainline tunnels on both sides, using a screw conveyor or belt conveyor to remove slag, and assembling the shield tunnel segments. Preferably, the assembly method can be through-joint assembly.

[0048] As a preferred embodiment of the present invention, the shield tunnel segments at the interface between the connecting channel and the tunnel are prefabricated glass fiber reinforced tunnel segments.

[0049] As a preferred embodiment of the present invention, step S3 specifically includes: supporting the interface between the transverse connecting channel and the tunnel by using cast-in-place reinforced concrete longitudinal beams and rectangular high-strength steel pipe concrete composite structural columns, and pre-setting the column spacing, preferably 5 meters, and reserving steel bar connectors on the shield tunnel segments to achieve the consolidation with the cast-in-place reinforced concrete longitudinal beams, while reserving longitudinal waterproof grooves on the shield tunnel segments.

[0050] As a preferred embodiment of the present invention, step S5 specifically includes: using a horizontal milling head to widen the upper and lower parts of the excavation area between the main line and the transverse connecting passage on both sides of the tunnel, and replacing the excavator head with a bucket to transport the slag for slag removal.

[0051] As a preferred embodiment of the present invention, step S6 specifically includes: performing preliminary support and secondary lining on the excavated area that has been expanded; setting up a steel arch frame installation machine, an anchor drilling machine, and a shotcrete robot within the initial support area to complete the preliminary support of the secondary lining area; then performing symmetrical secondary lining support on the secondary lining area; treating the joint between the cast-in-place concrete longitudinal beam and the cast-in-place concrete secondary lining; reserving a steel rebar connector on the joint surface of the reinforced concrete longitudinal beam; and pre-embedding a centrally embedded steel plate waterstop at the joint.

[0052] As a preferred embodiment of the present invention, step S7 specifically includes: after clearing the main tunnels on both sides, transporting the open-face tunneling machine to the transverse connecting passage, preparing for the construction of the connecting passage, breaking the shield segments at the symmetrical secondary lining area and the transverse connecting passage, and using the open-face tunneling machine to construct the connecting passage.

[0053] Example 1:

[0054] like Figure 1 As shown, the tunnel is divided into four sections: shield excavation zone 1, widening zone 2, transverse connecting passage zone 3, and secondary lining zone 4. It also includes shield tunnel segments 7, high-strength steel-concrete composite structural columns 6, precast fiberglass reinforced tunnel segments 5, and platform slabs 8. The entire tunnel is excavated symmetrically on both sides, and all construction methods are consistent.

[0055] The following steps are required:

[0056] Within the shield excavation area 1, a 7.7m shield machine will excavate the main subway tunnels on both sides. Slag will be removed using a screw conveyor or belt conveyor, and shield segments with a thickness of 400mm will be assembled using continuous joints. At the same time, precast fiberglass reinforced segments 5 will be used at the interface between the transverse connecting passage and the tunnel.

[0057] Support is provided at the interface between the transverse connecting passage and the tunnel, using 1000×1600mm reinforced concrete cast-in-place longitudinal beams and 600×600mm rectangular high-strength steel-concrete composite structural columns, spaced 5m apart. Figure 2 As shown, steel rebar connectors are reserved at 9 joints between the segment and the cast-in-place reinforced concrete beam to achieve a fixed connection with the cast-in-place reinforced concrete longitudinal beam. At the same time, longitudinal waterproof grooves are reserved at the ends of the segment.

[0058] After the support is completed, remove the fiberglass reinforced pipe section 5 at the interface of the transverse connecting passage. The excavator then enters the site, as... Figure 3 As shown, preparations are underway for widening the excavation.

[0059] like Figure 4 , 5 As shown, a transverse milling head was used to excavate the expansion zone 2 at the connection between the main line and the transverse passage on both sides of the tunnel, divided into upper and lower sections. During muck removal, the excavator head was replaced with a bucket to transport the excavated soil.

[0060] Preliminary support and secondary lining were carried out on the expanded excavation area 2, which had been expanded. Within the initial support area, a steel arch frame installation machine, an anchor drilling machine, and a shotcrete robot were set up to complete the preliminary support of the secondary lining area 4.

[0061] Subsequently, the above equipment was used to symmetrically support the secondary lining zone 4.

[0062] After the secondary lining is completed, treatment is carried out at 10 joints between the cast-in-place concrete longitudinal beams and the cast-in-place concrete secondary lining, such as... Figure 2 As shown, a steel rebar connector is reserved on the joint surface of the reinforced concrete longitudinal beam, and an embedded steel plate waterstop is pre-embedded in the joint 10.

[0063] After completing the excavation and support work and clearing the main tunnels on both sides, the open-face tunneling machine will be transported to the transverse connecting passage for construction.

[0064] Remove the pipe segments at the junction of the symmetrical secondary lining zone 4 and the transverse connecting channel, and use an open-type tunneling jacking machine to construct the connecting channel.

[0065] After the construction of the connecting passages on both sides is completed, the platform slab 8 will be installed.

Claims

1. A construction method for a separated island subway platform based on a small-section excavation using mechanical methods, characterized in that, Includes the following steps: S1. A tunnel boring machine will be used to excavate the main tunnels on both sides first; S2. Fiberglass reinforced shield tunnel segments are installed at the interface between the transverse connecting passage and the tunnel. S3. After the main tunnels on both sides are completed, high-strength steel-concrete composite structure columns will be poured at the transverse connecting passage to be constructed. S4. After completing the support of the main tunnels on both sides, remove or break the fiberglass shield tunnel segments at the interface between the transverse connecting passage and the tunnel. S5. Transport the excavation equipment to the construction site and use mechanical methods to excavate small sections at both ends of the transverse connecting channel. S6. Perform preliminary support and secondary lining on the excavated soil to prepare for the transverse connection channel. S7. After the expansion excavation of the connecting channel between the two lines is completed, the excavation equipment for the connecting channel will enter the site to excavate the connecting channel between the two lines. S8. Clean the tunnel and install platform panels; S9. Complete the construction of the subway platform structure.

2. The construction method for a separated island subway platform based on a small-section mechanical excavation method according to claim 1, characterized in that, Step S1 specifically includes: using a tunnel boring machine to excavate the main subway tunnels on both sides, using a screw conveyor or belt conveyor to remove slag, and assembling the tunnel segments.

3. The construction method for a separated island subway platform based on a small-section mechanical excavation method according to claim 1, characterized in that, The shield tunnel segments at the interface between the transverse connecting channel and the tunnel are made of precast glass fiber reinforced segments.

4. The construction method for a separated island subway platform based on a small-section mechanical excavation method according to claim 1, characterized in that, Step S3 specifically includes: supporting the interface between the transverse connecting channel and the tunnel, using cast-in-place reinforced concrete longitudinal beams and rectangular high-strength steel pipe concrete composite structural columns, and pre-setting the column spacing, reserving steel connectors at the joints between the tunnel segments and the cast-in-place reinforced concrete beams to achieve the consolidation with the cast-in-place reinforced concrete longitudinal beams, and reserving longitudinal waterproof grooves for the shield tunnel segments.

5. The construction method for a separated island subway platform based on a small-section mechanical excavation method according to claim 1, characterized in that, Step S5 specifically includes: using a horizontal milling head to widen the upper and lower parts of the tunnel at the connection between the main line and the transverse passage on both sides of the tunnel; when removing the slag, the excavator head is replaced with an excavator bucket to transport the slag for removal.

6. The construction method for a separated island subway platform based on a small-section mechanical excavation method according to claim 1, characterized in that, Step S6 specifically includes: performing preliminary support and secondary lining on the excavated area that has been expanded; setting up a steel arch frame installation machine, anchor drilling rig, and shotcrete robot within the initial support area to complete the preliminary support of the secondary lining area; then performing symmetrical secondary lining support on the secondary lining area; treating the joint between the cast-in-place concrete longitudinal beam and the cast-in-place concrete secondary lining; reserving a steel rebar connector on the joint surface of the reinforced concrete longitudinal beam; and pre-embedding a centrally embedded steel plate waterstop at the joint.

7. The construction method for a separated island subway platform based on a small-section mechanical excavation method according to claim 1, characterized in that, Step S7 specifically includes: after clearing the main tunnels on both sides, transporting the open-face tunneling machine to the transverse connecting passage, preparing for the construction of the connecting passage, breaking the shield segments at the symmetrical secondary lining area and the transverse connecting passage, and using the open-face tunneling machine to construct the connecting passage.

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