Construction method of subway station closely passing through existing comprehensive pipe gallery

Abstract

The application provides a construction method of a subway station closely passing through an existing comprehensive pipe gallery of a foundation pit, realizes the problem of passing through the existing structure of the foundation pit during most of the subway construction, discards the traditional treatment methods such as breaking and restoring or the construction of the cut-and-cover method, realizes the in-situ protection of the pipe gallery and the synchronous construction of the structure by using the L-shaped support beam permanent and temporary combined technical means, and realizes the situation that the monitoring data of the pipe gallery is normal during the construction process, the data change trend is stable, there is no abnormal settlement or deformation, all the data is within the controllable range, and there is no obvious leakage of the station structure roof after the construction, and the technical means has good economy and production value.

Description

Technical Field

[0001] The present invention relates to the field of subway construction, and in particular to a construction method for a subway station that is closely attached to and passes through an existing comprehensive pipeline corridor under a foundation pit. Background Art

[0002] With the continuous development of urban rail transit and urban underground integrated pipeline corridors, newly planned subway stations often intersect with existing underground integrated pipeline corridors. Improper design or construction can easily lead to deformation of the pipeline corridor structure, affecting the quality and durability of the new subway station structure, and posing a significant safety hazard. Traditional construction methods have the following disadvantages: 1) The existing pipeline corridor must be demolished and restored in situ after station construction is completed. This method is costly and difficult to coordinate, and the subsequent restoration significantly impacts the pipeline corridor's inherent stress and ongoing functionality. 2) The station foundation pit spans a large area, and the large-section underground excavation method is difficult to design, complex, and carries high safety risks.

[0003] In order to realize the station structure construction under the existing large-section integrated pipeline corridor without affecting each other, and to achieve the in-situ protection of the integrated pipeline corridor during the process and the synchronous construction of the structure, a safe, economical and efficient technical method is urgently needed. Summary of the Invention

[0004] The main purpose of the present invention is to provide a construction method for a subway station that is closely attached to and passes through an existing integrated pipeline corridor under a foundation pit, thereby solving the problem that when the station structure is constructed under an existing large-section integrated pipeline corridor, the integrated pipeline corridor will be damaged and synchronous construction cannot be carried out.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: a construction method for a subway station closely adhering to an existing integrated pipeline corridor passing through a foundation pit, the method comprising:

[0006] S1. Excavate the soil symmetrically on both sides of the utility corridor to the bottom of the utility corridor, and construct temporary column piles symmetrically on both sides of the utility corridor;

[0007] S2. Arrange monitoring points above and on both sides of the integrated pipeline corridor;

[0008] S3: Excavate the soil on both sides of the bottom of the integrated pipe gallery, set up buckle brackets to form an operating platform, construct L-shaped support beams and triangular concrete supports under the beams, and reserve structural steel connectors, water-stop steel plates, and vents;

[0009] S4. After the strength of the support beams reaches the design value, gradually slope and excavate, remove the soil at the bottom of the integrated pipeline corridor, and construct the main enclosure structure within the integrated pipeline corridor. During the excavation process, increase the monitoring frequency simultaneously;

[0010] S5. Construct the station structure under the integrated pipeline corridor and complete the base plate, middle plate, and side walls under the integrated pipeline corridor;

[0011] S6. Set up a full-height buckle bracket on the middle plate and use assembled walkway plates to fix and connect them to construct the operation channel;

[0012] S7. Chisel out the construction joints on the top plate of the support beams, clean out the connector sleeves on both sides, install a water-swelling waterstop and a reusable grouting hose on each side, and lay a polymer waterproof membrane close to the bottom of the integrated pipe gallery.

[0013] S8. Use the steel connectors reserved on the L-shaped support beam to effectively connect the main structure roof steel bars on both sides from top to bottom, completing the roof sunken design and ensuring that the roof closely fits under the integrated pipeline corridor;

[0014] S9. After the structural reinforcement is completed, pre-embed the surrounding pump pipes, the middle pump pipes, and the grouting pipes in the concrete at the bottom of the integrated pipe gallery, and arrange pressure sensors 7 at the corners of the four corners close to the bottom of the integrated pipe gallery;

[0015] S10. Install the formwork in different areas and reinforce the formwork;

[0016] S11. The bottom of the integrated pipe gallery is cast with anti-seepage self-compacting concrete that meets the design strength. The concrete is transported from bottom to top through the pre-buried pump pipe using a ground pump 15, and local vibration is performed using a flat vibrator.

[0017] S12. Remove the formwork support, use a geological radar detector to conduct a comprehensive inspection of the top plate, and fill the gaps with double liquid slurry;

[0018] S13. Static force is used to break down temporary column piles to the bottom of the foundation pit, thus achieving the permanent and temporary connection of the L-shaped support beam and the top plate tightly fitting under the integrated pipeline corridor, thus completing the in-situ protection of the integrated pipeline corridor.

[0019] In the preferred solution, the integrated pipe corridor described in step S3 is initially supported and protected by temporary columns φ1200mm and L-shaped support beams. The top plate is designed to be sunken, connectors are embedded on both sides of the support beams, and φ100mm 135° elbow stainless steel pipes are embedded on both sides of the support beams.

[0020] In the preferred solution, step S8 connects the sleeve connectors reserved at the support beam to install the top plate reinforcement, realizes the top plate sinking treatment through the L support beam 1, and connects the two top plates to make their structure continuous and realizes the permanent connection of the L support beam.

[0021] In the preferred solution, step S9 pre-buries two pump pipes and grouting pipes at different heights, and uses the values ​​collected by the pressure sensor and the condition of the pump pipe slurry flow to preliminarily determine whether the top plate is closely attached to the integrated pipeline corridor after concrete pouring.

[0022] In the preferred solution, step S11 uses C40 impermeable self-compacting concrete, and uses a reserved pump pipe to pressurize the concrete from the bottom of the tunnel to the structural surface.

[0023] In the preferred solution, in step S12, the geological radar detector scans the top plate, and the grouting pipe pre-buried in step S9 is used to promptly perform 1:16 dual-liquid grouting treatment on the gap locations.

[0024] In the preferred solution, the grouting pipe is DN50 and is arranged every 3m in the horizontal and vertical directions in the pre-buried concrete at the bottom of the integrated pipeline corridor.

[0025] In the preferred solution, the temporary column piles described in step S2 are distributed at a spacing of 5m.

[0026] In the preferred solution, the excavation position described in step S3 extends 70 cm into the integrated pipeline corridor, the excavation depth is 2 m, and a C20 plain concrete cushion layer is applied to level the base.

[0027] In the preferred embodiment, the cast pump pipes described in step S9 are respectively arranged in the pre-embedded concrete at the bottom of the integrated pipe gallery 6 at 5 cm and 10 cm away from the bottom of the integrated pipe gallery.

[0028] The present invention provides a construction method for a subway station that is closely attached to and passes through an existing comprehensive pipe gallery in a foundation pit, which has the following beneficial effects:

[0029] 1. The present invention provides a construction method for a subway station that closely adheres to an existing integrated pipeline corridor beneath a foundation pit. This method enables station structure construction beneath an existing large-section integrated pipeline corridor, while protecting the corridor in situ and enabling simultaneous construction of the structure without affecting each other. This simultaneous construction improves construction efficiency and reduces construction time.

[0030] 2. The present invention provides a construction method for a subway station that closely passes under an existing comprehensive pipeline corridor in a foundation pit, which solves the problem of passing under existing structures in the foundation pit during most subway construction. It abandons traditional treatment methods such as demolition and restoration or dark excavation construction, and uses L-shaped support beams and Yonglin combined with technical means to achieve in-situ protection of the pipeline corridor and synchronous construction of the structure. During the construction process, the pipeline corridor monitoring data showed no abnormalities, the data change trend was stable, there was no abnormal settlement or deformation, and all data were within the controllable range. After construction, there was no obvious leakage in the station structure roof. The technical means have good economic efficiency and production value. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below with reference to the accompanying drawings and examples:

[0032] Figure 1 It is the main enclosure plan layout of the present invention;

[0033] Figure 2It is a longitudinal sectional view of the main enclosure of the present invention;

[0034] Figure 3 This is a schematic diagram of grouting below the main enclosure of the present invention;

[0035] Figure 4 This is a large-scale drawing of the L-shaped support beam of the present invention.

[0036] In the figure: L-shaped support beam 1; exhaust hole 2; temporary support plate 3; upper layer steel bars of top plate 4; lower layer steel bars of top plate 5; integrated pipe gallery 6; pressure sensor 7; middle pump pipe 8; surrounding pump pipes 9; pipe gallery retaining piles 10; S piles 11; steel support 12; crown beam 13; concrete support 14; ground pump 15; steel bar connector 16; station center plate 17. DETAILED DESCRIPTION

[0037] Example 1

[0038] like Figure 1-4 As shown in the figure, the construction method of the existing integrated pipeline corridor under the foundation pit of the subway station includes the following steps:

[0039] (1) Use machinery to symmetrically slope and excavate the soil above and on both sides of the integrated pipeline corridor to the bottom of the corridor, remove the original corridor waterproofing, S piles 11, crown beams 13, steel supports 12, corridor retaining piles 10 and other retaining structures, and then construct temporary column piles symmetrically on both sides of the integrated pipeline corridor with a spacing of 5m;

[0040] (2) Arrange monitoring points above and on both sides of the tunnel;

[0041] (3) Excavate the soil on both sides of the tunnel bottom, with the excavation surface extending about 70 cm into the tunnel and the excavation depth being about 2 m. Apply a C20 plain concrete cushion layer to level the base, set up a buckle bracket to form an operating platform, construct an L-shaped support beam and a triangular concrete support 14 under the beam, and reserve structural steel connectors, water-stop steel plates, and observation vents during the process;

[0042] (4) After the strength of the support beam reaches the design value, gradually slope and excavate, digging out the soil at the bottom of the tunnel until it is about 3m away from the bottom of the tunnel. Construct the main enclosure structure within the tunnel, and increase the monitoring frequency during the excavation process to ensure that there is no excessive settlement or displacement in the tunnel;

[0043] (5) Construct the station structure under the tunnel, and complete the tunnel bottom plate, middle plate (post-casting holes are reserved at the temporary column pile positions), and side walls;

[0044] (6) A full-height buckle bracket is set up on the middle plate, and an assembled walkway plate is used to fix and connect the operating channel;

[0045] (7) Chisel out the support beam (top plate construction joint) and clean out the connector sleeves on both sides. Install a water-expandable water stop strip and a repeatable grouting hose on each side, and lay a polymer waterproof membrane close to the bottom of the pipe gallery;

[0046] (8) Using the connectors reserved on the L-support beam, the main structure roof steel bars on both sides are effectively connected from top to bottom, completing the roof sunken design and making the structural plate continuous, so that the roof is closely attached to the pipe gallery;

[0047] (9) After the structural reinforcement construction is completed, pre-buried concrete pump pipes (5cm and 10cm away from the bottom of the tunnel) and DN50 grouting pipes (one every 3m horizontally and vertically) are placed at the bottom of the tunnel, and pressure sensors 7 are placed at the corners of the tunnel close to the bottom of the tunnel;

[0048] (10) Install the formwork in different areas and reinforce the formwork;

[0049] (11) As the surrounding area is closed, vibrators cannot be used directly during pouring. Therefore, the bottom of the tunnel gallery is cast with anti-seepage self-compacting concrete that meets the design strength. A method similar to the tunnel invert arch secondary lining casting is adopted. The concrete is transported from bottom to top through the pre-buried pump pipe using the ground pump 15 on the station middle plate 17, and local vibration is carried out using a flat vibrator.

[0050] (12) After the top slab concrete reaches the designed strength, remove the formwork support and use a geological radar detector to conduct a comprehensive inspection of the top slab. If there are gaps, use double-liquid slurry filling to deal with them;

[0051] (13) Static force is used to remove the temporary column piles to the bottom of the foundation pit, thereby achieving the permanent and temporary connection of the L-shaped support beam and the top plate closely fitting under the integrated pipeline corridor 6, thus completing the in-situ protection of the integrated pipeline corridor;

[0052] In the preferred solution, in step (3), temporary columns (φ1200) + L-shaped support beams are used for top protection in the early stage of the tunnel. To achieve a close fit under the existing tunnel, the top plate is designed to be sunken after meeting the station clearance design requirements. Connectors are embedded on both sides of the support beams to facilitate subsequent structural reinforcement connection. φ100 stainless steel pipes (135° elbows) are embedded on both sides of the support beams to provide ventilation and observation during the subsequent concrete pouring, ensuring the overall quality of the concrete pouring.

[0053] In the preferred solution, step (8) connects the sleeve connectors reserved at the support beam to install the top plate reinforcement, realizes the sinking of the top plate through the L support beam, and connects the two top plates to make their structure continuous, ensuring the overall quality of the station structural plate and realizing the permanent connection of the L support beam.

[0054] In the preferred embodiment, step (9) pre-buries two pump pipes and grouting pipes of different heights, and the values ​​collected by the pressure gauge and the condition of the pump pipe slurry flow can be used to preliminarily determine whether the top plate is closely attached to the pipe corridor after concrete pouring.

[0055] In the preferred solution, in order not to affect the existing pipe gallery structure, step (11) uses C40 impermeable self-compacting concrete under the premise that vibrating rods can no longer be used, and the concrete is pressed from the bottom of the pipe gallery to the structural surface using a reserved pump pipe.

[0056] In the preferred embodiment, in step (12), the top plate is scanned by a geological radar detector, and the DN50 grouting pipe pre-buried in step (9) is used to promptly perform 1:16 double-liquid grouting treatment on the position where the gap exists, and the nearby grouting pipes are observed until all the slurry leaks out to avoid water leakage in the later stage of the structure.

[0057] Example 2

[0058] A subway project features a two-story, 11-meter-high island platform station. The station is 323 meters long and 20.3 meters wide at standard sections. The station was constructed using the open-cut method. An existing utility corridor existed within the foundation pit. Field measurements revealed that the corridor, a three-compartment, large-section reinforced concrete structure, is approximately 22 meters long, 12 meters wide, and 5 meters high. Located within the foundation pit, the corridor is arranged perpendicular to the station.

[0059] The original plan was to demolish the utility corridor and restore it in place after station construction was completed. However, since the utility corridor was already in operation and involved many different types of pipelines, coordination was extremely difficult and the construction cost was high.

[0060] The construction technology of this scheme can not only realize the in-situ protection of the integrated pipeline corridor, but also simultaneously construct the station structure, so that the structure can pass closely under the integrated pipeline corridor.

[0061] The specific implementation steps are as follows:

[0062] (1) As shown in Figures 2 and 3, temporary column piles of φ1200 + L-shaped support beams 1 are used to support the top of the integrated pipe corridor in the early stage. During the construction of the L-shaped support beams, the top plate steel bar connectors and exhaust holes 2 should be embedded in advance. During the excavation of the soil at the bottom of the pipe corridor, the construction monitoring frequency should be increased.

[0063] (2) Figure 1 and Figure 4 A full-height bracket (900mm*900mm*1500mm) was installed on the middle plate, and the prefabricated walkway slab was installed. The top plate's upper layer of reinforcement (4) was connected to the connectors provided at both ends of the L-shaped support beam (1). The lower layer of reinforcement (5) was raised every three spans (2.7m) in both the horizontal and vertical directions. Temporary support plates (3) supported the reinforcement framework. Pre-buried connectors were used to effectively connect the lower row of reinforcement to the top plate and weld them to the frame bars (for securing).

[0064] (3) Figure 1 and Figure 4 The formwork was installed in sections, and the temporary support plate 3 was gradually lowered before the top support was returned to the top for reinforcement. During construction, two Φ150 pump pipes 8 were symmetrically arranged in the middle of the tunnel floor (one for backup, one for use, with the top end of the pump pipe approximately 10 cm from the tunnel floor, the bottom end exposed 50 cm, and equipped with a waterstop steel ring). Four similar Φ150 pump pipes 9 were arranged around the tunnel floor (with the top end of the pump pipe approximately 5 cm from the tunnel floor). Repeatable grouting hoses were arranged in the horizontal and vertical directions along the upper steel bars of the top plate. Wireless sensor pressure gauges 7 were placed around the tunnel floor, close to the tunnel floor.

[0065] (4) Figure 1 、 Figure 2 and Figure 4 The bottom of the tunnel gallery is cast with C40P8 self-compacting concrete for the top plate. A ground pump is used to transport concrete upward from the pre-buried Φ150 middle pump pipe 8 in the middle. A flat vibrator is used for local vibration. When concrete flows out of the Φ150 surrounding pump pipe 9, it is sealed in time; if concrete does not flow out of the surrounding pump pipe 9 and there is no concrete observed in the exhaust hole 2, the delivery pump pipe is replaced with the surrounding pump pipe 9 at that position for transportation. The surrounding pressure sensors 7 and exhaust holes 2 can monitor whether the concrete is filled densely.

[0066] (5) After the top slab concrete reaches the designed strength, remove the formwork support and conduct a comprehensive inspection of the top slab using a geological radar detector. If there are gaps, use the pre-buried DN50 grouting pipe to promptly perform 1:16 double-liquid grouting treatment on the gaps. Observe the nearby grouting pipes until all the grout has leaked out to avoid water leakage in the later stages of the structure.

[0067] (6) Static force is used to break down the temporary column piles to the bottom of the foundation pit, thus achieving the permanent and temporary connection of the L-support beam 1 and completing the in-situ protection of the integrated pipeline corridor.

[0068] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be the technical solutions set forth in the claims, including equivalent alternatives to the technical features of the technical solutions set forth in the claims. In other words, equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A construction method for a subway station that closely passes under a foundation pit and has an existing integrated pipeline corridor, characterized by: S1. Above the integrated pipe corridor, the soil on both sides is symmetrically sloped and excavated to the bottom of the integrated pipe corridor (6), and temporary column piles are symmetrically constructed on both sides of the integrated pipe corridor; S2. Arrange monitoring points above and on both sides of the integrated pipeline corridor (6); S3, excavate the soil on both sides of the bottom of the integrated pipe gallery (6), set up a buckle bracket to form an operating platform, construct an L-shaped support beam (1) and a triangular concrete support (14) under the beam, and reserve a steel bar connector (16), a water-stop steel plate and an exhaust hole (2); S4. After the strength of the L-shaped support beam reaches the design value, gradually slope and excavate, dig out the soil at the bottom of the integrated pipeline corridor (6), and construct the main enclosure structure within the scope of the integrated pipeline corridor (6). During the excavation process, the monitoring frequency is increased simultaneously; S5. Construct the station structure under the integrated pipe gallery (6) and complete the bottom plate, middle plate, and side wall under the integrated pipe gallery (6); S6. Set up a full-height buckle bracket on the middle plate and use assembled walkway plates to fix and connect them to construct the operation channel; S7, chisel out the construction joint of the L-shaped support beam top plate, clean out the connector sleeves on both sides, install a water-expandable water stop strip and a repeatable grouting hose on each side, and lay a polymer waterproof membrane close to the bottom of the integrated pipe gallery (6); S8, using the steel bar connector (16) reserved on the L-shaped support beam (1), effectively connecting the main structure top plate steel bars on both sides from top to bottom, completing the top plate sinking design, and achieving the top plate closely fitting under the integrated pipe corridor (6); S9, after the top plate reinforcement construction is completed, pre-buried concrete surrounding pump pipes (8), middle pump pipes (9) and grouting pipes are placed at the bottom of the integrated pipe gallery (6), and pressure sensors (7) are arranged at the corners of the four sides close to the bottom of the integrated pipe gallery (6); S10. Install the formwork in different areas and reinforce the formwork; S11. The bottom of the integrated pipe gallery (6) is cast with anti-seepage self-compacting concrete that meets the design strength. The concrete is transported from bottom to top through the pre-buried pump pipe using a ground pump (15). A flat vibrator is used for local vibration. S12. Remove the formwork support, use a geological radar detector to conduct a comprehensive inspection of the top plate, and use double-liquid grouting to treat the gaps; S13, statically breaking the temporary column piles to the bottom of the foundation pit, achieving the permanent and temporary combination of the L-shaped support beam (1) and the top plate closely adhering to the integrated pipeline corridor (6) underneath, completing the in-situ protection of the integrated pipeline corridor.

2. The construction method of a subway station closely adhering to an existing integrated pipeline corridor passing through a foundation pit according to claim 1 is characterized by: In the early stage of the integrated pipe corridor (6) described in step S3, temporary columns φ1200mm and L-shaped support beams (1) are used for top protection, and a sunken design is performed on the top plate. Steel bar connectors are embedded on both sides of the L-shaped support beams, and φ100mm 135° elbow stainless steel pipes are embedded on both sides of the L-shaped support beams.

3. The construction method of a subway station closely passing through an existing comprehensive pipeline corridor in a foundation pit according to claim 1 is characterized by: Step S8 connects the steel bar connectors reserved at the L-shaped support beam to install the top plate steel bars, realizes the top plate sinking treatment through the L-shaped support beam (1), and connects the two top plates to make their structure continuous and realizes the permanent connection of the L-shaped support beam (1).

4. The construction method of a subway station closely adhering to an existing integrated pipeline corridor passing through a foundation pit according to claim 1 is characterized by: Step S9 pre-buries two pump pipes and grouting pipes of different heights, and uses the values ​​collected by the pressure sensor and the condition of the pump pipe slurry flow to preliminarily determine whether the top plate is closely attached to the integrated pipe gallery (6) after the concrete is poured.

5. The construction method of a subway station closely passing through an existing comprehensive pipeline corridor in a foundation pit according to claim 1 is characterized by: In step S11, C40 anti-seepage self-compacting concrete is used to pressurize the concrete from the bottom of the integrated pipe gallery to the structural surface using a reserved pump pipe.

6. The construction method of a subway station closely adhering to an existing integrated pipeline corridor passing through a foundation pit according to claim 1 is characterized by: In step S12, the geological radar detector scans the top plate, and the grouting pipe pre-buried in step S9 is used to promptly perform 1:16 double-liquid grouting treatment on the gap positions.

7. The construction method of a subway station closely adhering to an existing integrated pipeline corridor passing through a foundation pit according to claim 6 is characterized by: The grouting pipe is DN50 and is arranged every 3m in the horizontal and vertical directions in the concrete at the bottom of the integrated pipe gallery (6).

8. The construction method of a subway station closely adhering to an existing integrated pipeline corridor passing through a foundation pit according to claim 1 is characterized by: In step S1, temporary column piles are arranged at a spacing of 5m.

9. The construction method of a subway station closely adhering to and passing through an existing comprehensive pipeline corridor in a foundation pit according to claim 1 is characterized by: In step S3, the excavation position extends 70 cm into the integrated pipeline corridor, the excavation depth is 2 m, and a C20 plain concrete cushion layer is applied to level the base.

10. The construction method of a subway station closely passing through an existing comprehensive pipeline corridor in a foundation pit according to claim 1 is characterized by: In step S9, the pump pipes are respectively arranged in the concrete at the bottom of the integrated pipe gallery (6) at a distance of 5 cm and 10 cm from the bottom of the integrated pipe gallery (6).

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