Construction device and method for removing existing underground continuous wall of subway station

Abstract

The application relates to the technical field of shield construction, in particular to a device and method for removing an underground continuous wall of an existing subway station. The device for removing the underground continuous wall of the existing subway station comprises a safety door, a door frame and a door leaf, the door frame comprises a ring-shaped frame and a partition plate arranged on the inner side of the ring-shaped frame, the ring-shaped frame is fixedly connected with the underground continuous wall and faces the removal area of the underground continuous wall, the partition plate divides the internal space of the ring-shaped frame into an upper part and a lower part, and the door leaf is provided with two door leaves arranged on the upper side and the lower side of the partition plate respectively. The application adopts a layered removal construction mode, effectively avoids the collapse of the sandwich soil, guarantees the construction safety, and is helpful to realize the efficient and safe removal of the underground continuous wall in the geologically unstable area.

Description

Technical Field

[0001] This application relates to the technical field of tunnel boring machine (TBM) construction, and in particular to a construction device and method for removing diaphragm walls in existing subway stations. Background Technology

[0002] Currently, when a new subway line passes under an existing subway station, it is necessary to excavate a tunnel under the existing subway station. Since there is a diaphragm wall under the existing subway station, it is necessary to remove part of the diaphragm wall to ensure that the tunnel can pass smoothly under the existing subway station.

[0003] New subway lines also require new subway stations. The initial step for constructing new subway stations is to build diaphragm walls and excavate foundation pits on the ground. When a new subway station is adjacent to an existing one, the diaphragm walls of the new station (referred to as the new diaphragm wall) and the existing station (referred to as the existing diaphragm wall) exist side-by-side. During the process of the subway tunnel passing under the existing station and extending to the new station, the tunnel boring machine (TBM) needs to pass through the existing diaphragm wall and the new diaphragm wall sequentially during the shield receiving process, before entering the receiving shaft located in the foundation pit of the new subway station to complete the shield receiving.

[0004] Therefore, in order to receive the tunnel boring machine (TBM), it is necessary to manually excavate and remove the soil between the newly built diaphragm wall, the existing diaphragm wall, and the two underground continuous walls within the receiving shaft. However, if the soil layer in the area where the underground continuous wall is to be removed involves unstable geological conditions such as soft soil or confined aquifers, the soil layer is usually frozen before the TBM and the underground continuous wall are removed to reduce the safety risks caused by geological instability.

[0005] However, in actual construction, there are still dangerous situations such as the collapse of the core soil, which threaten the safety of construction workers and affect the smooth progress of construction. Therefore, how to ensure the efficient and safe removal of diaphragm walls in geologically unstable areas is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] This application provides a construction device and method for removing diaphragm walls in existing subway stations, which can help achieve efficient and safe removal of diaphragm walls in geologically unstable areas.

[0007] The first aspect is to provide a construction device for removing diaphragm walls in existing subway stations, employing the following technical solution:

[0008] A construction device for removing diaphragm walls in existing subway stations includes a safety door, comprising a door frame and a door leaf, wherein the door frame is disposed at an opening in the diaphragm wall;

[0009] The door frame includes an annular frame and a partition plate disposed inside the annular frame; the annular frame is fixedly connected to the diaphragm wall; the inner edge of the annular frame is located inside the opening of the diaphragm wall, so that the internal space of the door frame faces the area where the diaphragm wall is removed; the partition plate divides the internal space of the annular frame into an upper part and a lower part;

[0010] The door panels are provided in two parts, one on the upper side and the other on the lower side of the partition.

[0011] By adopting the above technical solution, when the soil between the newly built diaphragm wall and the existing diaphragm wall in the area to be demolished collapses, the door can be closed, thereby closing the safety door. The safety door can prevent the expansion of the soil between the diaphragm walls, thus preventing safety risks to construction workers. Simultaneously, because the door panels are set at different heights, construction workers can sequentially work on the areas to be demolished within the upper and lower door panels, ensuring the orderly progress of the diaphragm wall demolition and further reducing the risk of soil collapse.

[0012] Preferably, the door leaf is equipped with a pneumatic valve.

[0013] By adopting the above technical solution, the pneumatic valve can balance the air pressure inside and outside the safety door, preventing safety hazards caused by air pressure difference.

[0014] Preferably, the annular frame is square or circular, and the door leaf is square.

[0015] By adopting the above technical solutions, the square ring frame has the advantages of simple processing and low cost, while the circular ring frame can better match the shape of the area to be removed and has a better protective effect.

[0016] Preferably, it also includes an operating platform and an operating frame, the operating frame including a first operating platform and a second operating platform, the first operating platform being disposed at the bottom of the annular frame and the second operating platform being disposed on the horizontal side of the partition plate.

[0017] By adopting the above technical solution, the first operating platform is erected at the bottom of the ring frame to facilitate the construction personnel to enter the lower door leaf of the door frame, while the second operating platform is erected on the horizontal side of the partition board to facilitate the construction personnel to enter the upper door leaf of the door frame, so that the construction can proceed smoothly.

[0018] Preferably, it also includes an arc-shaped baffle, the surface of which is used to contact the sandwich soil in the excavation opening, and the two ends of which are used to contact the soil layer or the underground continuous wall.

[0019] By adopting the above technical solution, after the new diaphragm wall, the existing diaphragm wall and the sandwich soil are removed, the outer arc surface of the baffle plate abuts against the sandwich soil at the top of the removed area, and the two ends of the baffle plate abut against the soil layer or underground continuous wall at the bottom of the created area, thereby supporting the sandwich soil and preventing the sandwich soil from collapsing.

[0020] Preferably, the baffle comprises a plurality of arc-shaped plates arranged in a straight line, and adjacent arc-shaped plates are hinged to each other.

[0021] By adopting the above technical solution, multiple curved plates can be folded for easy storage, and it is also convenient to put the baffle into the chiseled opening, thereby facilitating the support of the sandwich soil.

[0022] Secondly, this application provides a method for removing diaphragm walls in existing subway stations, employing the aforementioned device for removing existing diaphragm walls, and including the following steps:

[0023] S1, take the midline of the height direction of the area to be removed in the diaphragm wall, and set the area above and below the midline as the first removal area and the second removal area, respectively.

[0024] S2, remove the newly built diaphragm wall, existing diaphragm wall and sandwich soil corresponding to the first removal area;

[0025] S3, Set up supports for the sandwich soil above the first excavation area to prevent the sandwich soil from collapsing;

[0026] S4, chisel down to remove the existing diaphragm wall and the interlayer soil to the second removal area;

[0027] S5, remove the newly built diaphragm wall, existing diaphragm wall and sandwich soil corresponding to the second removal area;

[0028] S6, remove the remaining newly built diaphragm walls, existing diaphragm walls and sandwich soil, and complete the removal of the underground continuous wall.

[0029] By adopting the above technical solution and using a layered construction method with a first and second removal area, the risk of collapse is low when the first removal area is constructed because the opening after removal is small and the exposed core soil is also less. Furthermore, after the first removal area is completed, the core soil is supported, effectively preventing the collapse of the core soil at the top of the removal opening. After removing the core soil from the first removal area, the removal continues downwards to the second removal area, effectively reducing the amount of core soil within the removal area. Therefore, during construction in the second removal area, the risk of core soil collapse is effectively reduced, ensuring personnel safety and the smooth progress of construction.

[0030] Preferably, in step S1, a safety door is used and fixed to the underground continuous wall of the newly built subway station, so that the partition plate is aligned with the center line in the height direction of the area to be demolished; the part of the area to be demolished that is directly opposite the upper door leaf of the safety door is set as the first demolition area, and the part that is directly opposite the lower door leaf is the second demolition area.

[0031] By adopting the above technical solution, the safety door can be closed in time when the interlayer soil collapses unexpectedly, thereby preventing the interlayer soil from spreading further and endangering personnel safety. At the same time, the upper and lower doors of the safety door separate the first removal area and the second construction area, facilitating orderly construction. The safety door also enhances the strength of the newly built diaphragm wall, providing support and protection for personnel.

[0032] Preferably, the support in step S3 is configured as shotcrete support with wire mesh and located between two diaphragm walls.

[0033] By adopting the above technical solution and using shotcrete with wire mesh support, the sandwiched soil can be supported to prevent collapse. On the other hand, the shotcrete with wire mesh support can be fixedly connected to the diaphragm wall, thereby improving the strength and stability of the support.

[0034] Preferably, in step S5, after removing the newly built diaphragm wall, the existing diaphragm wall, and the sandwich soil corresponding to the second removal area, foamed concrete is filled into the removal area.

[0035] By adopting the above technical solution, foamed concrete, as a lightweight concrete material, is easy to construct. When filled in the excavation area, it can serve as a supplement to the diaphragm wall, thereby providing effective support to the excavation area and preventing collapse caused by the reduced strength of the diaphragm wall after excavation. This ensures the stability of the existing station above and, due to its low density, facilitates the smooth progress of subsequent tunnel boring machine (TBM) construction.

[0036] In summary, the present invention has at least one of the following beneficial technical effects:

[0037] 1. When removing the soil sandwiched between existing diaphragm walls, newly constructed diaphragm walls, or two diaphragm walls, safety doors are used. If the soil sandwiched between the newly constructed and existing diaphragm walls in the area to be removed collapses, the door can be closed, thus closing the safety door. The safety door can prevent the expansion of the soil sandwiched between the walls, thus preventing safety risks to construction workers. Furthermore, because door panels of different heights are installed, construction workers can sequentially work on the areas to be removed within the upper and lower door panels, ensuring the orderly progress of the diaphragm wall removal work and further reducing the risk of soil sandwiched between the walls collapsing.

[0038] 2. By adopting a layered construction method with a first and second removal area, the risk of collapse is lower when the first removal area is constructed because the opening after removal is smaller and less exposed core soil is exposed. Furthermore, after the first removal area is completed, the core soil is supported to effectively prevent collapse of the top core soil within the removal opening. After removing the core soil from the first removal area, the removal continues downwards to the second removal area, effectively reducing the amount of core soil within that area. Therefore, during construction in the second removal area, the risk of core soil collapse is significantly reduced, ensuring personnel safety and the smooth progress of construction.

[0039] 3. Remove the newly constructed diaphragm wall, existing diaphragm wall, and core soil corresponding to the second removal area; fill the removal area with foamed concrete. Foamed concrete, as a lightweight concrete material, is easy to construct. When filled into the removal area, it serves as a supplement to the diaphragm wall, effectively supporting the area and preventing collapse due to reduced strength after removal. This ensures the stability of the existing station above. Furthermore, its low density facilitates subsequent tunnel boring machine (TBM) construction. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the overall structure of the security door in an embodiment of this application;

[0041] Figure 2 This is a schematic diagram of the structure after the security door is installed on the existing ground ties in the embodiment of this application;

[0042] Figure 3 This is a schematic diagram of the baffle structure in an embodiment of this application;

[0043] Figure 4 This is a side view of the operating frame and safety door in an embodiment of this application;

[0044] Figure 5 This is a schematic diagram of the construction method S1 for removing the underground diaphragm wall of the existing subway station in this application;

[0045] Figure 6 This is a schematic diagram of the construction method S2 for removing the underground diaphragm wall of the existing subway station in this application;

[0046] Figure 7 This is a schematic diagram of construction methods S3-S4 for the removal of underground diaphragm walls in existing subway stations in this application;

[0047] Figure 8 This is a schematic diagram of the construction method S5 for removing the underground diaphragm wall of the existing subway station in this application;

[0048] Figure 9 This is a further construction schematic diagram of the existing subway station underground diaphragm wall removal construction method S5 in this application;

[0049] Figure 10 This is a schematic diagram of the construction method S6 for removing the underground diaphragm wall of an existing subway station in this application.

[0050] The attached diagram is labeled as follows: 1. Safety door; 11. Door frame; 111. Circular frame; 112. Divider plate; 12. Door leaf; 13. Air pressure valve; 2. Baffle; 3. Operating frame; 31. First operating platform; 32. Second operating platform; 4. Existing diaphragm wall; 5. Sandwich soil; 6. New diaphragm wall; 7. Support; 8. First removal area; 9. Second removal area; 10. Foamed concrete. Detailed Implementation

[0051] The following is in conjunction with the appendix Figure 1-10 The present invention will be described in further detail below.

[0052] This embodiment discloses a construction device for removing diaphragm walls in existing subway stations, referring to... Figure 1 The system includes a safety door 1, which consists of a door frame 11 and door panels 12. The door frame 11 is located in the area of ​​the diaphragm wall to be excavated. Specifically, the door frame 11 includes an annular frame 111 and a partition plate 112 located inside the annular frame 111. Both the annular frame 111 and the partition plate 112 are made of metal profiles and welded together. The annular frame 111 is fixedly connected to the diaphragm wall using anchors such as expansion bolts to ensure its stability. The partition plate 112 divides the internal space of the annular frame 111 into an upper and lower section. Two door panels 12 are provided, located above and below the partition plate 112 respectively, and are hinged to the annular frame 111, each equipped with a lock.

[0053] Reference Figure 2 During construction, safety door 1 will be installed in the end shaft and fixedly connected to the diaphragm wall of the new subway station, isolating the area to be excavated from the outside. When the soil 5 sandwiched between the newly built diaphragm wall 6 and the existing diaphragm wall 4 in the area to be excavated collapses, door leaf 12 can be closed to shut off safety door 1. Safety door 1 can prevent the expansion of the soil 5 and thus prevent safety risks to construction workers. At the same time, because door leaves 12 are set at different heights, construction workers can carry out construction on the areas to be excavated in the upper door leaf 12 and the areas to be excavated in the lower door leaf 12 in sequence, which can ensure that the excavation of the diaphragm wall is carried out in an orderly manner and further reduce the risk of collapse of the soil 5.

[0054] Reference Figure 2 Furthermore, a pressure valve 13 is installed on the door leaf 12. The pressure valve 13 can balance the air pressure inside and outside the safety door 1 to prevent safety hazards caused by air pressure difference.

[0055] In this embodiment, the annular frame 111 is square, and the door leaf 12 is also square. The upper end of the annular frame 111 extends above the area to be removed, and the lower end of the annular frame 111 extends below the area to be removed, so that the internal space of the annular frame 111 faces the area to be removed, so as to facilitate the smooth progress of construction.

[0056] Since the area to be removed from the diaphragm wall is actually circular, as a preferred embodiment of this application, the annular frame 111 can also be set as a circle corresponding to the size of the area to be removed, while the door leaf 12 remains square.

[0057] Reference Figure 3 In this embodiment, the construction device for removing the diaphragm wall of an existing subway station also includes an arc-shaped baffle 2. The baffle 2 comprises multiple arc-shaped plates arranged in a straight line, and adjacent arc-shaped plates are hinged together. After the newly constructed diaphragm wall 6, the existing diaphragm wall 4, and the core soil 5 are removed, the outer arc surface of the baffle 2 abuts against the core soil 5 at the top of the removal area, and the two ends of the baffle 2 abut against the soil layer or diaphragm wall at the bottom of the removal area, thereby supporting the core soil 5 and preventing the core soil 5 from collapsing.

[0058] Reference Figure 4 Furthermore, in order to ensure the smooth progress of construction, the existing underground continuous wall removal construction device for subway stations also includes an operating frame 3. The operating frame 3 includes a first operating platform 31 and a second operating platform 32. The first operating platform 31 is erected at the bottom of the annular frame 111 to facilitate the construction personnel to enter the lower door leaf 12 of the door frame 11. The second operating platform 32 is erected on the horizontal side of the partition plate 112 to facilitate the construction personnel to enter the upper door leaf 12 of the door frame 11.

[0059] This embodiment also discloses a method for removing diaphragm walls in existing subway stations, applicable to the removal of existing diaphragm walls 4 and newly constructed diaphragm walls 6 when a new subway line passes under an existing subway station and the new subway station is adjacent to the existing subway station. The aforementioned method for removing diaphragm walls in existing subway stations is also employed.

[0060] Since newly constructed subway lines typically include both northbound and southbound lines, two parallel tunnels need to be constructed. Demolition zones need to be designated on both the existing diaphragm wall 4 and the newly constructed diaphragm wall 6, and sections of the diaphragm wall in these zones need to be removed to ensure the tunnel can smoothly pass through the diaphragm wall without significantly impacting the stability of the existing station. The demolition zones on the diaphragm wall are usually circular in shape and correspond to the tunnel's cross-section. After demolition, a circular portal will be formed in the diaphragm wall for the tunnel boring machine to pass through.

[0061] In this embodiment, the removal of the diaphragm wall is carried out in the foundation pit of the newly built subway station. Specifically, the tunnel boring machine (TBM) needs to pass through the existing diaphragm wall 4, the interlayer soil 5, and the newly built diaphragm wall 6 in sequence before finally entering the receiving shaft in the foundation pit of the new subway station to complete the TBM reception. The removal direction of the diaphragm wall is opposite to the TBM construction direction. Therefore, within the receiving shaft, the newly built diaphragm wall 6 needs to be removed first, followed by the interlayer soil 5 and the existing diaphragm wall 4.

[0062] Therefore, in order to facilitate the efficient and safe removal of diaphragm walls in geologically unstable areas, the specific steps of the existing subway station diaphragm wall removal construction method in this application are as follows:

[0063] S1, refer to Figure 5 Take the midline of the height direction of the area to be removed in the underground continuous wall, and set the area above and below the midline as the first removal area 8 and the second removal area 9, respectively.

[0064] Safety door 1 is used and fixed to the underground continuous wall of the newly built subway station, so that the partition plate 112 is aligned with the center line in the height direction of the area to be demolished; the upper door 12 of safety door 1 faces the first demolition area 8 and the lower door 12 faces the second demolition area 9.

[0065] S2, refer to Figure 6 The newly built diaphragm wall 6, the existing diaphragm wall 4, and the sandwich soil 5 corresponding to the first excavation area 8 are excavated.

[0066] S3, refer to Figure 7 Supports 7 are installed on the sandwich soil 5 above the first excavation area 8 to prevent the sandwich soil 5 from collapsing. The support 7 is specifically a wire mesh shotcrete support, which is set between the two diaphragm walls to prevent the sandwich soil 5 from collapsing. Furthermore, the wire mesh shotcrete support can be integrated with the diaphragm walls, thereby improving the strength and stability of the support 7.

[0067] Besides using shotcrete with wire mesh support, the sandwich soil 5 can also be shielded simply by using baffle 2. Furthermore, when performing shotcrete with wire mesh support construction, baffle 2 can also function as a concrete formwork.

[0068] S4, see reference Figure 7 The existing diaphragm wall 4 and the interstitial soil 5 are then chiseled downwards to the second chiseling area 9. This further removes the interstitial soil 5 within the chiseling area, preventing its collapse during construction of the second chiseling area 9.

[0069] S5, refer to Figure 8 and Figure 9The newly constructed diaphragm wall 6, the existing diaphragm wall 4, and the sandwich soil 5 corresponding to the second excavation area 9 are removed; foamed concrete 10 is then filled into the excavation area. As a lightweight concrete material, foamed concrete 10 is easy to construct. When filled into the excavation area, it can supplement the diaphragm wall and thus provide effective support 7 for the excavation area, preventing collapse caused by the reduced strength of the diaphragm wall after its removal, ensuring the stability of the existing station above, and its low density facilitates the smooth progress of subsequent shield tunneling.

[0070] S6, see reference Figure 10 Remove the remaining newly built diaphragm wall 6, existing diaphragm wall 4 and sandwich soil 5 in the area to be excavated, and complete the excavation work in the area to be excavated.

[0071] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A construction device for removing diaphragm walls in existing subway stations, characterized in that, The system includes a safety door (1), which includes a door frame (11) and door panels (12). The door frame (11) is located in the area where the diaphragm wall is constructed. The door frame (11) includes an annular frame (111) and a partition plate (112) located inside the annular frame (111). The annular frame (111) is fixedly connected to the diaphragm wall. The internal space of the annular frame (111) faces the area where the diaphragm wall is removed. The partition plate (112) divides the internal space of the annular frame (111) into an upper part and a lower part. There are two door panels (12), which are respectively located on the upper and lower sides of the partition plate (112). The system also includes an operating frame (3), which includes a first operating platform (31) and a second operating platform (32). The first operating platform (31) is located at the bottom of the annular frame (111), and the second operating platform (32) is located on the horizontal side of the partition plate (112).

2. The excavation and construction device for the diaphragm wall of an existing subway station according to claim 1, characterized in that, The door leaf (12) is equipped with a pneumatic valve (13).

3. The excavation and construction device for the diaphragm wall of an existing subway station according to claim 1, characterized in that, The annular frame (111) is set to be square or circular, and the door leaf (12) is set to be square.

4. The excavation and construction device for the diaphragm wall of an existing subway station according to claim 1, characterized in that, It also includes an arc-shaped baffle (2), the surface of which is used to contact the sandwich soil (5) in the excavation area, and the two ends of which are used to contact the soil layer or the underground continuous wall.

5. The excavation and construction device for the diaphragm wall of an existing subway station according to claim 4, characterized in that, The baffle (2) comprises a plurality of arc-shaped plates arranged in a straight line, and adjacent arc-shaped plates are hinged to each other.

6. A method for removing diaphragm walls in existing subway stations, characterized in that, The construction device for removing the underground diaphragm wall of an existing subway station as described in claim 1 is used, and includes the following steps: S1, take the midline of the area to be removed in the height direction of the underground diaphragm wall, and set the area above and below the midline as the first removal area (8) and the second removal area (9), respectively; S2, remove the newly built diaphragm wall (6), the existing diaphragm wall (4) and the core soil (5) corresponding to the first removal area (8); S3, set up a support (7) for the core soil (5) above the first removal area (8) to prevent the core soil (5) from collapsing; S4, remove the existing diaphragm wall (4) and the core soil (5) downward to the second removal area (9); S5, remove the newly built diaphragm wall (6), the existing diaphragm wall (4) and the core soil (5) corresponding to the second removal area (9); S6, remove the remaining newly built diaphragm wall (6), the existing diaphragm wall (4) and the core soil (5), and complete the removal of the underground diaphragm wall.

7. The method for removing the underground diaphragm wall of an existing subway station according to claim 6, characterized in that, In step S1, a safety door (1) is used and the safety door (1) is fixed on the underground continuous wall of the newly built subway station so that the partition plate (112) is aligned with the center line in the height direction of the area to be demolished; the part of the area to be demolished that is directly opposite the upper door leaf (12) of the safety door (1) is set as the first demolished area (8), and the part that is directly opposite the lower door leaf (12) is the second demolished area (9).

8. The method for removing the diaphragm wall of an existing subway station according to claim 6, characterized in that, The support (7) mentioned in step S3 is set as a wire mesh shotcrete support and is located between two underground continuous walls.

9. The method for removing the underground diaphragm wall of an existing subway station according to claim 6, characterized in that, In step S5, after removing the newly built diaphragm wall (6), the existing diaphragm wall (4) and the sandwich soil (5) corresponding to the second removal area (9), foamed concrete (10) is filled in the removal area.

Images