A support structure for underpass anti-pullout piles and its construction method

Abstract

The present invention discloses a support structure for underpasses with anti-pullout piles and a construction method thereof, which solves the problems of high difficulty and low safety factor in the prior art of removing anti-pullout piles during concealed excavation of existing tunnels and / or buildings. The support structure for underpasses with anti-pullout piles of the present invention comprises a connecting steel pipe that connects the existing building structure and the tunnel segment using a pipe curtain method, wherein a curved beam plate is provided on the side of the tunnel segment corresponding to the connecting steel pipe, and a reinforcing ring beam is provided on the side of the existing building structure corresponding to the connecting steel pipe, one end of the connecting steel pipe passes through the tunnel segment and is connected to the curved beam plate, and the other end passes through the existing building structure and is connected to the reinforcing ring beam and / or the existing building structure; after one side of the existing building structure is connected to the tunnel segment via the connecting steel pipe, the existing anti-pullout pile is removed, and then the other side of the existing building structure is connected to the tunnel segment via the connecting steel pipe. The present invention uses the pipe curtain method to construct connecting steel pipes, and uses the connecting steel pipes to connect the tunnel segments and the internal curved steel beams with the upper existing building structure to form a whole, so that the tunnel segments and the upper structure have a common anti-floating effect, and can safely and efficiently realize the safe construction of tunnels passing under existing buildings.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, in particular to a support structure for underpass anti-pullout piles and a construction method thereof. Background Art

[0002] With the advancement of urbanization, more and more cities are building subways to alleviate pressure on surface transportation. Because line planning lags behind urban development, subway excavation inevitably requires passing beneath existing buildings. During underground space development, the use of covert excavation methods to penetrate existing tunnels and / or buildings often requires the removal of retaining piles and pullout piles, significantly impacting existing buildings and compromising the anti-floating properties of the original structures. This makes construction difficult and presents technical risks, especially in adverse geological conditions.

[0003] Existing anti-floating methods involve cutting existing pullout piles and connecting them to existing underground structures. For example, patent publication number CN 113062750 A discloses a method for constructing a tunnel structure under an underground structure with pullout piles. When a pullout pile is encountered during excavation, the main reinforcement of the pullout pile is chiseled out, steel arches are erected on either side of the pile, and the concrete of the pullout pile is statically broken. The steel arches are densely arranged around the piles and welded to the main reinforcement of the pullout piles. Concrete is then sprayed to seal the primary support. Finally, after the primary support reaches the designed strength and deformation stabilizes, the secondary lining is poured, completing the construction of the tunnel structure under the pullout piles of the underground structure. However, this method first removes the pullout piles and then connects them to the subsequent building structure, which compromises the original anti-floating stability. Furthermore, when mechanical excavation is used, the exposed steel bars cannot be cut and welded to the steel arches. Furthermore, the removed pullout piles are difficult to integrate with the tunnel segments, undermining the stability of the existing structure and posing a significant safety hazard. Therefore, this method is not suitable for mechanical excavation.

[0004] To address this problem, patent publication number CN 113803073 A discloses a construction method for tunnel structures with manual clearance of water-rich sand layers, offering a solution for shield tunneling under pile foundations. First, the area around the pull-out piles is frozen. After cutting and lining are completed, the piles are thawed and backfilled with concrete, followed by mechanical excavation. This method expands the application scope of mechanical excavation, but the freeze-thaw process and concrete backfilling steps are complex, costly, and only applicable to shallow depths. While the freezing method is suitable for water-rich layers, construction when groundwater is low can lead to risks such as landslides. Patent publication number CN 116291552 A discloses an anti-floating structure for shallow tunnels, providing a tunnel structure for passing under underground structures with pull-out piles. This structure achieves excellent anti-floating properties for shallow tunnels by installing anti-floating longitudinal beams within the tunnel, connecting them to the pull-out piles below. However, this method does not consider situations where dense buildings above the construction structure require the pull-out piles to pass under them. Furthermore, this method is only applicable to shallow tunnel construction and does not consider construction under existing buildings.

[0005] In order to solve the above problems, it is necessary to design a structural form and construction method of pull-out piles for underground structures using a mechanical underground excavation method to solve the problem of damage to anti-floating safety caused by the need to remove pull-out piles under underground excavation of existing tunnels and / or buildings. Summary of the Invention

[0006] In response to the deficiencies in the above-mentioned background technology, the present invention proposes a support structure for underpasses with pull-out piles and a construction method thereof, which solves the problems in the prior art of underground excavation under existing tunnels and / or buildings, which require the removal of pull-out piles, resulting in damage to anti-floating safety and high construction difficulty.

[0007] The technical solution of the present invention is implemented as follows: a support structure for underpass anti-pullout piles, comprising connecting steel pipes that connect the existing building structure and tunnel segments using a pipe curtain method, wherein a curved beam plate is provided on the side of the tunnel segment corresponding to the connecting steel pipe, and a reinforcing ring beam is provided on the side of the existing building structure corresponding to the connecting steel pipe, one end of the connecting steel pipe passes through the tunnel segment and is connected to the curved beam plate, and the other end passes through the existing building structure and is connected to the reinforcing ring beam and / or the existing building structure; after one side of the existing building structure is connected to the tunnel segment via the connecting steel pipe, the existing anti-pullout piles are removed, and then the other side of the existing building structure is connected to the tunnel segment via the connecting steel pipe. The above structure avoids the risk of temporary failure of the anti-pullout effect caused by first removing the anti-pullout piles and then reconnecting them, which is present in the conventional method of underpass anti-pullout piles.

[0008] Further preferably, a cuttable hole is provided on the tunnel segment at the connection corresponding to the connecting steel pipe, the curved beam plate is fitted with the inner wall of the tunnel segment, the connecting steel pipe passes through the cuttable hole and the curved beam plate and is fixedly connected to the curved beam plate through a second connecting end plate.

[0009] It is further preferred that after the cuttable opening is cut, a segment portal is formed for the connecting steel pipe to pass through. The cuttable opening is reinforced with steel bars and a steel lining is provided on the inside of the cuttable opening. The curved beam plate can seal the inside of the cuttable opening. The curved beam plate is fixedly connected to the tunnel segment, and the outside of the cuttable opening is grouting-treated.

[0010] As a preferred embodiment, the curved beam plate is a curved steel beam comprising a plurality of annular curved steel sheets. Adjacent curved steel sheets are welded together and staggered with the tunnel segments. The axial length of the curved steel sheet along the tunnel segment is twice the segment width.

[0011] As another preferred solution, the curved beam-slab is a concrete lining beam-slab, which is fixed on the inner wall of the tunnel segment; this structure is applicable to the case of mining method underpasses with pull-out piles of existing structures.

[0012] Further preferably, a construction portal is provided on the side of the existing building structure corresponding to the connecting steel pipe, a reinforcing ring beam is provided on the inside of the construction portal, and grouting reinforcement is performed on the outside of the construction portal. The connecting steel pipe passes through the construction portal and is connected to the existing building structure through a first connecting end plate.

[0013] Further preferably, a support structure is provided in the area to be excavated within the existing building structure. The connecting steel pipe is an oblique straight pipe or an arc-shaped pipe; and a drill hole for fixing pull-out piles is reserved at the lower portion of the tunnel segment.

[0014] A construction method for a support structure under a pull-out pile comprises the following steps:

[0015] S1: Determine the size and model of the connecting steel pipe and the curved beam plate, and determine the position of the pipe segment ring with the cuttable opening based on the position relationship.

[0016] S2: A support structure is installed in the area to be excavated within the existing building structure. A reinforcing ring beam is installed inside the construction portal. Grouting reinforcement is performed outside the construction portal to reinforce the soil outside the existing building. Simultaneously, the proposed tunnel is excavated and the tunnel segments are assembled. After the ring of segments containing the cuttable openings in the tunnel segments is assembled to the first predetermined position, grouting reinforcement is performed outside the cuttable openings to reinforce the soil outside the segments. Subsequently, curved pipe curtain technology is used to connect steel pipes between the existing building structure and the tunnel segments. It should be noted that the connecting steel pipes used in this curved pipe curtain technology can originate from the existing building structure and be received by the tunnel segments; alternatively, the connecting steel pipes can originate from the tunnel segments and be received by the existing building structure. A reasonable selection should be made based on the working conditions.

[0017] S3: Fix one end of the connecting steel pipe to the existing building structure through the first connecting end plate; fix the other end of the connecting steel pipe to the tunnel segment through the second connecting end plate and the curved beam plate.

[0018] S4: Continue the planned tunnel excavation and directly remove the pull-out piles by mechanical excavation when encountering them.

[0019] S5: After the proposed tunnel passes through the existing building structure and the segment ring with the cuttable opening in the tunnel segment is assembled to the second predetermined position, the curved pipe curtain technology is used to construct connecting steel pipes between the other side of the existing building structure and the tunnel segment.

[0020] S6: Repeat step S3 to complete the connection of the connecting steel pipes between the left and right sides of the existing building structure and the tunnel segments, and connect the curved beams and slabs to the existing building structure through the connecting steel pipes to form an integral anti-floating structure.

[0021] When the overall common anti-floating structure does not meet the anti-floating requirements, the reserved drilled holes at the bottom of the tunnel segments are fixed with newly constructed pull-out piles to increase the overall anti-floating performance.

[0022] The beneficial effects of the present invention are as follows: the present invention uses the pipe curtain method to construct connecting pipes, and connects the tunnel segments and the internal curved steel beams to the upper existing building structure through connecting steel pipes to form a whole, so that the tunnel segments and the upper structure have a common anti-floating effect, and can safely and efficiently achieve safe construction of tunnels passing under existing buildings. When the construction area encounters pull-out piles, the present invention adopts the method of fixing the tunnel segments and the upper structure with connecting steel pipes, so that both participate in anti-floating at the same time, which can effectively solve the problems of the upper structure anti-floating failure and structural cracking caused by the need to remove the pull-out piles of the upper structure during deep underground tunnel construction, greatly improving construction safety and construction efficiency.

[0023] Compared with the existing technology, the present invention proposes a structural form and construction method of underpass anti-pullout piles, which avoids the risk of temporary failure of the anti-floating effect caused by first breaking the anti-pullout piles and then reconnecting them in the conventional underpass anti-pullout pile method by setting an anti-floating structure that is first connected to the upper building structure. At the same time, this method changes the defect of the existing technology that only the mining method can be used to break the anti-pullout piles, and broadens the scope of application of the mechanical excavation method for constructing underground projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] Figure 1 This is a schematic diagram of one side of the support structure of the present invention.

[0026] Figure 2 It is a side view schematic diagram of the support structure of the present invention.

[0027] Figure 3 This is a schematic diagram of the support structure of the present invention using arc-shaped pipe fittings.

[0028] Figure 4 This is a schematic diagram of the curved beam-slab connection state in Example 1.

[0029] Figure 5 This is a schematic diagram of the supporting structure of the present invention using oblique straight pipes.

[0030] Figure 6 Schematic diagram of the side view of the construction of new pull-out piles.

[0031] Figure 7 This is a schematic diagram of the main view of the construction of new pull-out piles.

[0032] In the figure: 1: existing building or underground station, 2: connecting steel pipe, 3: tunnel segment, 4: pull-out pile, 41: new pull-out pile, 5: curved beam-slab, 51: front section small curved steel beam, 52: rear section small curved steel beam, 53: weld, 54: reinforcement layer, 55: bolt connection, 61: soil reinforcement outside existing building, 62: soil reinforcement outside segment, 71: first connection end plate, 72: second connection end plate, 8: supporting structure, 9: reinforced ring beam, 10: cuttable opening. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0034] like Figure 1 、 2 As shown in Example 1, a support structure for underpasses with pull-out piles includes a connecting steel pipe 2 that connects an existing building structure 1 and a tunnel segment 3 using a pipe curtain method; that is, the corresponding connecting steel pipe is constructed using a pipe curtain. The existing building structure 1 can also be an underground station structure. A curved beam plate 5 is provided on the side of the tunnel segment 3 corresponding to the connecting steel pipe 2, and a reinforcing ring beam 9 is provided on the side of the existing building structure 1 corresponding to the connecting steel pipe 2. One end of the connecting steel pipe 2 passes through the tunnel segment 3 and is connected to the curved beam plate 5, while the other end passes through the existing building structure 1 and is connected to the reinforcing ring beam 9 and / or the existing building structure 1. The above structure is suitable for new subway stations or tunnels that pass under existing buildings. When pull-out piles are encountered within the construction area, the fixed segments and the upper existing building structure are used so that both participate in anti-floating. This can effectively solve the problems of anti-floating failure and structural cracking of the upper structure caused by the need to remove the pull-out piles of the upper structure during deep underground tunnel construction, thereby achieving safe and convenient construction.

[0035] After one side of the existing building structure 1 is connected to the tunnel segment 3 via the connecting steel pipe 2, the existing pull-out piles 4 are removed, and then the other side of the existing building structure 1 is connected to the tunnel segment 3 via the connecting steel pipe 2. The above structure can be applied when using the hidden excavation method to pass under an existing tunnel or above-ground building, where pull-out piles are present along the predetermined construction route. After the new anti-floating structure is constructed, the existing pull-out piles are removed. This avoids the risk of temporary failure of the anti-floating effect caused by first removing the pull-out piles and then reconnecting them, which is a common method of passing under the pull-out piles.

[0036] As an embodiment, the tunnel segments 3 are provided with cuttable openings 10 at the locations corresponding to the connection points with the connecting steel pipes 2. The tunnel segments 3 are identical to existing structures, i.e., they are composed of several segment rings spliced ​​together. The cuttable openings 10 are provided on the corresponding segment rings. After the cuttable openings 10 are chiseled out, the corresponding segment portals are formed. During the prefabricated segment processing, cuttable openings are provided at the corresponding locations, and reinforcement is applied around the openings. The curved beam plate 5 is fitted and fixed to the inner wall of the tunnel segment 3. The connecting steel pipe 2 passes through the cuttable openings 10 and the curved beam plate 5 and is fixedly connected to the curved beam plate 5 via a second connecting end plate 72. The fixing method can be welding or bolting.

[0037] As an embodiment, the cuttable opening 10 is removed to form a segment portal for the connecting steel pipe 2 to pass through. Reinforcement is used around the cuttable opening 10, and a steel lining is provided inside the cuttable opening 10 to further enhance its robustness. The curved beam 5 seals the inside of the cuttable opening 10 while also providing a connection to the connecting steel pipe. The curved beam 5 is fixedly connected to the tunnel segment 3, and grouting is performed on the outside of the cuttable opening 10. Segment outer soil reinforcement 62 is formed outside the cuttable opening 10 to ensure its sealing.

[0038] In this embodiment, the curved beam plate 5 is a curved steel beam comprising several small curved steel beam sections. Adjacent small curved steel beam sections are welded together and staggered with the tunnel segment 3 ring. During construction, the axial length of the small curved steel beam along the tunnel segment 3 is twice the ring width of the segment. The front small curved steel beam 51, corresponding to the first predetermined position of the cuttable opening, is welded to the rear small curved steel beam 52, forming an intermediate weld 53. Subsequent small curved steel beams are sequentially connected until the small curved steel beams are welded to the second predetermined position, forming the entire curved steel beam 5. The connecting end plates are fixedly connected to the curved steel beams by bolts 54. A reinforcement layer 54 is cast between the curved steel beams and the tunnel segment 3, ensuring the stability of the curved steel beams. The curved steel plates can be pre-perforated, and the connection to the segments can be replaced by rebar or bolting. This structure is suitable for tunnels excavated mechanically beneath existing buildings.

[0039] During construction, the proposed tunnel is first excavated. After the prefabricated segments for cutting openings are placed in the planned tunnel to the predetermined positions, curved pipe curtain technology is used to connect steel pipes between the existing superstructure and the tunnel segments that have been excavated. The connecting steel pipes connect the existing superstructure and the tunnel segments that have been excavated, so that the tunnel segments that have been excavated can provide anti-buoyancy to the existing superstructure through the connecting steel pipes. Construction of the proposed tunnel is then continued. When anti-pullout piles are encountered, they can be directly mechanically excavated and broken without worrying about the existing superstructure's insufficient anti-buoyancy. After the proposed tunnel passes through the existing superstructure, the curved pipe curtain technology can still be used to connect the existing superstructure and the proposed tunnel. Furthermore, curved steel beams can be set on the inner surface of the tunnel and connected to the connecting steel pipes on the left and right sides, so that the tunnel segments and the superstructure can achieve a common anti-buoyancy effect.

[0040] Curved pipe curtain technology is used to connect steel pipes between the existing superstructure and the pre-excavated pipeline while tunneling the pipeline. Once the prefabricated segments with machinable holes are installed, a curved steel beam is placed in the tunnel. One end of the connecting beam is secured to the superstructure, while the other end passes through the segment portal and secures to the curved steel beam, securing the curved steel beam to the segment. As the tunnel advances, the curved steel beams are repeatedly placed in the tunnel and welded together until the other end of the tunnel is complete. The curved steel beams are connected to the superstructure via steel pipes, forming a single unit, ensuring that the tunnel segments and superstructure function together to resist buoyancy.

[0041] Example 2, a support structure for underpasses involving pullout piles, differs from Example 1 in that the curved beams and plates 5 are concrete lining beams and plates fixed to the inner wall of the tunnel segments 3. Replacing the curved steel plates with reinforced concrete structures can also be applied to underpasses involving pullout piles in existing structures using the mining method.

[0042] like Figure 3 As shown, based on Examples 1 or 2, a construction portal is provided on the side of the existing building structure 1 corresponding to the connecting steel pipe 2. A reinforcing ring beam 9 is provided inside the construction portal, and the outside of the construction portal is reinforced by grouting. The connecting steel pipe 2 passes through the construction portal and is connected to the existing building structure 1 via a first connecting end plate 71. This connection can be achieved by welding or bolting. To enhance the stability of the existing building structure during use, a support structure 8 can be installed in the area to be excavated within the existing building structure 1.

[0043] As a preferred option, the connecting steel pipes 2 are oblique straight or curved pipes. The steel pipes used in pipe curtain construction can be straight, which fully utilizes the load-bearing properties of steel and conserves steel. Concrete can be poured into the steel pipes to improve the load-bearing properties of the connecting steel pipes. If the above structure does not meet the anti-floating requirements, pullout piles 4 can be installed in the holes reserved for fixing pullout piles at the bottom of the tunnel segments 3, thereby improving the overall anti-floating performance.

[0044] Example 3: A construction method for a support structure under a pullout pile as described in Example 1 or 2, comprising the following steps:

[0045] S1: According to the construction plan and the force calculation results, the size and model of the connecting steel pipe 2 and the curved beam plate 5 are determined, and the position of the pipe segment ring with the cuttable opening 10 is determined based on the position relationship; the pipe segment ring with the cuttable opening 10 has two predetermined positions corresponding to both sides of the existing building structure 1; when processing the prefabricated pipe segments, the cuttable opening is set at the corresponding position, the steel bars around the opening are reinforced, and a steel lining is set inside the opening.

[0046] S2: A support structure 8 is installed in the area to be excavated in the existing building structure 1. A reinforcing ring beam 9 is installed inside the construction portal. Grouting reinforcement is performed outside the construction portal to form soil reinforcement 61 outside the existing building structure to ensure sealing. Simultaneously, the proposed tunnel excavation and tunnel segments 3 are assembled. After the segment ring containing the cuttable opening 10 is assembled to the first predetermined position, a connecting steel pipe 2 is constructed between the existing building structure 1 and the tunnel segments 3 using the curved pipe curtain technique. The connecting steel pipe 2 can be a curved pipe fitting or an oblique straight pipe fitting. Using a straight pipe fitting fully utilizes the mechanical properties of steel and saves steel. Concrete can be poured into the steel pipe to improve its mechanical properties. It should be noted that the connecting steel pipe constructed using the curved pipe curtain technique can originate from the existing building structure and be received by the tunnel segments, or originate from the tunnel segments and be received by the existing building structure. The appropriate choice should be made based on the working conditions.

[0047] S3: Fix one end of the connecting steel pipe 2 to the existing building structure 1 through the first connecting end plate 71; the fixing method can be welding, bolting, etc. to ensure the firmness of the connection. Fix the other end of the connecting steel pipe 2 to the tunnel segment 3 through the second connecting end plate 72 and the curved beam plate 5; specifically, the curved beam plate 5 is constructed in the tunnel segment 3 corresponding to the cuttable opening 10, and then the cuttable opening 10 is chiseled out to form a segment portal. The connecting steel pipe 2 passes through the segment portal and the curved beam plate 5 and is fixed to the curved beam plate 5 through the second connecting end plate 72. Grouting is performed between the curved beam plate 5 and the tunnel segment 3 and on the outside of the segment portal.

[0048] S4: Continue tunneling the proposed tunnel and directly remove the pull-out pile 4 by mechanical excavation when encountering it. This avoids the risk of temporary failure of the anti-floating effect caused by first removing the pull-out pile and then reconnecting it, which is common in conventional methods of underpassing pull-out piles.

[0049] S5: After the proposed tunnel passes through the existing building structure 1 and the segment ring containing the cuttable opening 10 in the tunnel segment 3 is assembled to the second predetermined position, the curved pipe curtain technology is used to connect the steel pipe 2 between the other side of the existing building structure 1 and the tunnel segment 3.

[0050] S6: Repeat step S3 to complete the connection of the connecting steel pipes 2 on the left and right sides of the existing building structure 1 and the tunnel segments 3, and connect the curved beam slab 5 to the existing building structure 1 through the connecting steel pipes 2 to form an integral common anti-floating structure.

[0051] like Figure 6 、 7As shown, when the overall anti-floating structure fails to meet anti-floating requirements, the overall anti-floating performance can be enhanced by drilling holes reserved below the tunnel segments 3 and installing new pullout piles 4. During construction, the curved steel plates can be replaced with a concrete lining structure. This overcomes the limitation of existing technology that only allows the use of mining methods to remove pullout piles, and broadens the scope of application of mechanical excavation methods for underground construction.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A support structure under a pull-out pile, characterized by: The invention comprises a connecting steel pipe (2) for connecting an existing building structure (1) and a tunnel segment (3) by adopting a pipe curtain method, wherein a curved beam plate (5) is provided on the side of the tunnel segment (3) corresponding to the connecting steel pipe (2), and a reinforcing ring beam (9) is provided on the side of the existing building structure (1) corresponding to the connecting steel pipe (2); one end of the connecting steel pipe (2) passes through the tunnel segment (3) and is connected to the curved beam plate (5), and the other end passes through the existing building structure (1) and is connected to the reinforcing ring beam (9) and / or the existing building structure (1); After one side of the existing building structure (1) is connected to the tunnel segment (3) via the connecting steel pipe (2), the existing pull-out pile (4) is removed, and then the other side of the existing building structure (1) is connected to the tunnel segment (3) via the connecting steel pipe (2).

2. The support structure for underpass anti-pullout piles according to claim 1 is characterized in that: A cuttable hole (10) is provided on the tunnel segment (3) at a connection corresponding to the connecting steel pipe (2); the curved beam plate (5) is fitted with the inner wall of the tunnel segment (3); the connecting steel pipe (2) passes through the cuttable hole (10) and the curved beam plate (5) and is fixedly connected to the curved beam plate (5) via a second connecting end plate (72).

3. The support structure for underpass anti-pullout piles according to claim 2 is characterized in that: After the cuttable opening (10) is cut, a segment opening for the connecting steel pipe (2) to pass through is formed. Steel bars are used to reinforce the periphery of the cuttable opening (10) and a steel lining is provided inside the cuttable opening (10). The curved beam plate (5) can seal the inside of the cuttable opening (10). The curved beam plate (5) is fixedly connected to the tunnel segment (3), and grouting is performed on the outside of the cuttable opening (10).

4. The support structure for underpasses with pull-out piles according to any one of claims 1 to 3, characterized in that: The arc-surface beam plate (5) is an arc-surface steel beam, which comprises a plurality of annular arc-surface steel sheets. Two adjacent arc-surface steel sheets are fixed by welding, and the arc-surface steel sheets and the tunnel segments (3) are arranged in an annular staggered manner.

5. The support structure for underpasses with anti-pullout piles according to any one of claims 1 to 3, characterized in that: The curved beam plate (5) is a concrete lining beam plate, and the concrete lining beam plate is fixed on the inner wall of the tunnel segment (3).

6. The support structure for underpasses with pull-out piles according to claim 1, characterized in that: A construction portal is provided on the side of the existing building structure (1) corresponding to the connecting steel pipe (2), a reinforcing ring beam (9) is provided on the inner side of the construction portal, and grouting reinforcement is performed on the outer side of the construction portal. The connecting steel pipe (2) passes through the construction portal and is connected to the existing building structure (1) via a first connecting end plate (71).

7. The support structure for underpasses with anti-pullout piles according to claim 6, characterized in that: A supporting structure (8) is provided in the area to be excavated within the existing building structure (1).

8. The support structure for underpasses with pull-out piles according to claim 1, characterized in that: The connecting steel pipe (2) is an oblique straight pipe or an arc-shaped pipe; a drill hole for fixing the pull-out pile (4) is reserved at the lower part of the tunnel segment (3).

9. A construction method for a support structure under a pullout pile according to claim 1, characterized in that: Here are the steps: S1: Determine the size and type of the connecting steel pipe (2) and the curved beam plate (5), and determine the position of the segment ring with the cuttable opening (10) based on the positional relationship; S2: a support structure (8) is set up in the area to be excavated of the existing building structure (1), a reinforcing ring beam (9) is set up on the inner side of the construction portal, and grouting reinforcement is performed on the outer side of the construction portal to form a soil reinforcement (61) on the outer side of the existing building; the proposed tunnel is excavated simultaneously, and the tunnel segments (3) are assembled. After the segment ring containing the cuttable opening (10) in the tunnel segment (3) is assembled to the first predetermined position, grouting reinforcement is performed on the outer side of the cuttable opening (10) to form a soil reinforcement (62) on the outer side of the segment, and then a curved pipe curtain technology is used to connect the steel pipe (2) between one side of the existing building structure (1) and the tunnel segment (3); S3: fixing one end of the connecting steel pipe (2) to the existing building structure (1) via a first connecting end plate (71); fixing the other end of the connecting steel pipe (2) to the tunnel segment (3) via a second connecting end plate (72) and a curved beam plate (5); S4: Continue to excavate the proposed tunnel, and when encountering the pull-out pile (4), directly remove it by mechanical underground excavation; S5: After the proposed tunnel passes through the existing building structure (1), and the segment ring with the cuttable opening (10) in the tunnel segment (3) is assembled to the second predetermined position, the curved pipe curtain technology is used to connect the steel pipe (2) between the other side of the existing building structure (1) and the tunnel segment (3); S6: Repeat step S3 to complete the connection of the connecting steel pipes (2) between the left and right sides of the existing building structure (1) and the tunnel segments (3), and connect the curved beam plate (5) and the existing building structure (1) through the connecting steel pipes (2) to form an integral common anti-floating structure.

10. The construction method of the support structure under the anti-pulling pile according to claim 9, characterized in that: When the overall common anti-floating structure does not meet the anti-floating requirements, new anti-pullout piles (41) are constructed through the reserved drilled holes at the bottom of the tunnel segments (3) to increase the overall anti-floating performance.

Images