A soil reinforcement structure for repairing open-end cutterheads under normal pressure

Abstract

This utility model discloses a soil reinforcement structure for repairing a cutterhead under normal pressure, mainly comprising a tunnel boring machine (TBM) soil chamber, a cutterhead to be repaired, a working space, a pile reinforcement structure, a cover plate, a steel casing, and an arch support. The TBM is located in a stratum with a soft upper layer and a hard lower layer, densely packed with high-strength boulders, and the cutterhead has detached and urgently needs repair. The pile reinforcement structure is formed by interlocking reinforced concrete piles. The cover plate is a capping beam installed on the upper end of the pile reinforcement structure after its formation. The steel casing has a pre-reserved skylight to enhance ventilation and remove large boulders in front of the cutterhead. The arch support is formed by welding steel bars and sheet metal. This utility model has advantages such as adaptability to complex strata containing boulders, flexible adjustment of the reinforcement range, and effective control of stratum deformation and stability. It can effectively solve the problem of surrounding soil stability during TBM cutterhead repair, increase construction safety, and improve construction efficiency.

Description

Technical Field

[0001] This utility model relates to soil reinforcement measures before opening the cutterhead for replacement under normal pressure when the cutterhead of a tunnel boring machine is damaged during tunneling. Specifically, it relates to a soil reinforcement structure for repairing the cutterhead under normal pressure, belonging to the field of soil reinforcement for tunnel boring machines. Background Technology

[0002] With the continuous development of underground space in Chinese cities, urban rail transit construction is increasingly penetrating complex geological environments, often facing composite strata characterized by "soft upper layers and hard lower layers densely covered with isolated boulders." When the tunnel boring machine (TBM) cutterhead reaches areas with isolated boulders, problems such as jamming, severe cutter wear, and even cutterhead detachment are prone to occur. It is necessary to use the atmospheric pressure open-cell cutterhead replacement method for cutterhead repair. To ensure the smooth progress of the open-cell cutterhead replacement operation, it is necessary to reinforce the soil around the TBM cutterhead.

[0003] Traditional soil reinforcement measures before cutterhead repair often result in poor reinforcement effects, causing deformation of the surrounding strata and posing risks to the cutterhead repair work. Therefore, a soil reinforcement structure for atmospheric pressure open-chamber cutterhead repair is needed. Utility Model Content

[0004] This utility model provides a soil reinforcement structure for repairing cutterheads under normal pressure, aiming to solve the problem of cutterhead replacement during tunnel boring machine (TBM) excavation. To achieve the above objective, this utility model provides the following technical solution: a soil reinforcement structure for repairing cutterheads under normal pressure, characterized in that it includes a TBM soil chamber, a cutterhead to be repaired, a working space, a pile reinforcement structure, a cover plate, a steel casing, an arch support, and densely packed high-strength boulders with a soft upper layer and a hard lower layer.

[0005] Furthermore, when the tunnel boring machine is excavating in a stratum with soft upper layers and hard lower layers and dense boulders, the cutterhead is affected by the boulders and cannot work normally, requiring professional personnel to enter the soil chamber to repair the cutterhead.

[0006] Furthermore, an inert grout is filled into the earthen chamber and cement is added to form a low-strength solid inside the chamber.

[0007] Furthermore, pile reinforcement bodies are installed above and in front of the cutterhead. These pile reinforcement bodies are composed of different piles, all of which interlock to form a whole, serving as an isolation and reinforcement function. Pile A is a reinforced concrete pile with a diameter of 0.8m. The vertical clearance between the pile bottom and the tunnel boring machine is 0.5m, and the horizontal clearance between the pile core and the cutterhead is 0.3m. Adjacent piles interlock with a clearance of 0.2m, forming a whole and serving as an isolation function while preventing pile subsidence. Pile B is a reinforced concrete pile with a diameter of 1.0m. The bottom 11m is reinforced with fiberglass reinforcement to allow normal tunneling through the pile body after cutterhead repair. The horizontal clearance between the core of the outermost row of piles and the front of the cutterhead is 1.75m, and the bottom of the pile extends 6.4m below the top of the cutterhead. It interlocks with the surrounding piles with a clearance of 0.2m, forming a whole. Piles C are reinforced concrete piles with a diameter of 1.0m. The vertical clearance between the pile bottom and the tunnel boring machine (TBM) is 0.8m. The second row of piles has a horizontal clearance of 0.4m in front of the cutterhead, and the third row has a clearance of 1.1m in front of the cutterhead. Four piles (B piles) are placed on each side of the two rows. During construction, piles B and C interlock with each other by a clearance of 0.2m. To prevent any piles from settling, a cap plate is installed on top of each pile after all piles are formed. This cap plate connects all the piles and prevents pile settling from damaging the working space.

[0008] Furthermore, an 11m*3.4m*0.4m cover plate is installed above the pile reinforcement body and connected to the pile body below to prevent settlement of the pile reinforcement structure.

[0009] Furthermore, a steel casing with a diameter of 1.0m is embedded in the reserved skylight, 1m above the ground, and connected to the cover plate during construction to maintain its stability.

[0010] Furthermore, an arch support is constructed above the cutterhead of the tunnel boring machine using φ25mm@150 steel bars with a length of 1.5m. One end of the steel bar is anchored 200mm into the B pile body, and the other end is placed on the soil outside the shield shell. A square timber with grooves is placed between the shield shell and the steel bar to hold the steel bar. A 3mm thick sheet of iron is placed on top of the steel bar and welded to it. Mortar is filled between the sheet of iron and the soil.

[0011] This utility model has at least the following beneficial effects:

[0012] Adaptable to complex strata containing boulders: The soil reinforcement structure can effectively adapt to complex strata containing boulders and provide good reinforcement effect, providing a safe construction environment for cutterhead repair construction.

[0013] The reinforcement range can be flexibly adjusted: the soil reinforcement structure can flexibly control the reinforcement boundary according to the cutterhead repair needs, which ensures the safety of the core working area and avoids excessive reinforcement that would increase the cutting resistance of the cutterhead.

[0014] Effective control of ground deformation: The soil reinforcement structure can effectively limit the convergence deformation of the tunnel face during cutterhead replacement and effectively reduce surface settlement, maintaining the stability of surrounding buildings and structures. Attached Figure Description

[0015] Figure 1 This is a schematic diagram showing the spatial relationship between the cutter head to be repaired and the reinforcement structure.

[0016] Figure 2 This is a schematic diagram showing the spatial positions of the bottoms of piles B and A in the pile reinforcement system relative to the cutterhead of the tunnel boring machine.

[0017] Figure 3 This is a schematic diagram showing the spatial positions of piles B and C, the steel casing, and the tunnel boring machine cutterhead in the pile reinforcement system.

[0018] Figure 4 This is a schematic diagram showing the spatial position of the bottom of piles B and C in the pile reinforcement system relative to the cutterhead of the tunnel boring machine.

[0019] Figure 5 A schematic diagram showing the spatial position of the bottom of pile B and the cutterhead of the tunnel boring machine in the pile reinforcement system.

[0020] Figure 6 This is a plan view of the pile reinforcement structure.

[0021] Figure 7 This refers to the specific arrangement of the arch support.

[0022] In the diagram, 1-Shield tunneling machine soil chamber; 2-Cutoff head to be repaired; 3-Working space; 4-Pile reinforcement structure; 5-Cover plate; 6-Steel casing; 7-Arch support; 8-High-strength boulders densely distributed in soft upper and hard lower strata; 401-Pile A; 402-Pile B; 403-Pile C. Detailed Implementation

[0023] The technical solutions of this utility model will now be clearly and completely described with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0024] Reference Figure 1 This utility model provides a soil reinforcement structure for repairing a cutterhead under normal pressure, including a tunnel boring machine soil chamber 1, a cutterhead to be repaired 2, a working space 3, a pile reinforcement structure 4, a cover plate 5, a steel casing 6, an arch support 7, and a high-strength boulders stratum with soft upper and hard lower layers 8.

[0025] Furthermore, the cutterhead to be repaired is located in a stratum with a soft upper layer and a hard lower layer, densely packed with high-strength boulders. The bolts connecting the cutterhead flange and the front shield flange are broken, as are the bolts connecting the drive disc and the main bearing.

[0026] Furthermore, an inert grout is filled into the earthen chamber and cement is added to form a low-strength solid inside the chamber.

[0027] The inert grout is composed of cement, fly ash, yellow sand, bentonite and water. It is filled into the soil chamber before the pile reinforcement construction to prevent the concrete poured during pile construction from entering the soil chamber and causing difficulties in the later repair and cleaning of the cutterhead.

[0028] Furthermore, a pile reinforcement body is constructed above and in front of the tunnel boring machine cutterhead. The reinforcement body is formed by interlocking reinforced concrete piles. It is divided into pile A, pile B, and pile C.

[0029] The A piles are 0.8m diameter reinforced concrete piles with a vertical clearance of 0.5m between the pile bottom and the cutterhead, and a horizontal clearance of 0.3m behind the cutterhead at the pile center. A row of 12 piles is installed, with adjacent piles interlocking by a 0.2m margin, forming a unified structure that serves as a barrier and prevents pile subsidence. During construction, one pile is selected as a test pile. After driving, it is left to stand for one day to observe for borehole collapse. If collapse occurs, mud slurry wall protection or an upper casing is used for pile formation. If no collapse occurs, dry-hole pile formation is employed.

[0030] The B pile is a reinforced concrete pile with a diameter of 1.0m. The bottom 11m is reinforced with glass fiber reinforcement so that it can be excavated normally through the pile body after the cutterhead is repaired. The horizontal clearance from the center of the outermost pile to the front of the cutterhead is 1.75m. The bottom of the pile extends 6.4m below the top of the cutterhead. Ten piles are arranged and interlock with the surrounding piles with an interlocking amount of 0.2m to form a whole.

[0031] The C pile in question is a reinforced concrete pile with a diameter of 1.0m. The vertical clearance between the pile bottom and the cutterhead is 0.8m. Nine piles are arranged in the second row, with a horizontal clearance of 0.4m in front of the cutterhead. Nine piles are arranged in the third row, with a horizontal clearance of 1.1m in front of the cutterhead. Four B piles are arranged on each side of the two rows. During construction, the B and C piles interlock with each other, with an interlocking distance of 0.2m.

[0032] All piles were constructed using a skip-pile construction method to prevent cross-hole construction. The construction interval between adjacent pile positions was no less than 24 hours. During concrete pouring, the tremie pipe was lowered to approximately 30cm from the bottom of the hole, and a small hopper was used for direct pouring to reduce the impact of the concrete on the bottom of the hole. The final pouring volume was controlled, and the pouring height was 1.5m above the ground; over-pouring was strictly prohibited.

[0033] Furthermore, an 11m*3.4m*0.4m cover plate is constructed above the pile reinforcement to connect to the pile structure below. The cover plate uses C20 threaded steel for the main reinforcement, φ8@400 for the stirrups, and C18 steel bars for the reinforcing bars.

[0034] Furthermore, during the construction of the upper steel casing, eight 10*10*2cm triangular steel plates are welded to the outside, while the other side is kept close to the ground to prevent the steel casing from sinking.

[0035] Furthermore, an arch support is constructed above the cutterhead to stabilize the upper strata and provide a stable working space for cutterhead repair.

[0036] The arch support uses 1.5m long φ25mm@150 steel bars, one end of which is anchored 200mm into the pile body, and the other end is placed in the soil outside the shield shell. A 300*100*100mm square timber is placed outside the shield shell, with grooves carved into the timber to hold the steel bars. Two steel bars are lap-welded together in the middle. Before welding, a 3mm thick sheet of iron is placed on the steel bars, and the sheet of iron is welded to the steel bars. The gap between the sheet of iron and the soil is filled with mortar. The specific protection range is 120° of the arch crown.

[0037] Taking the example of a section of Metro Line N in a certain city where the cutterhead of the tunnel boring machine (TBM) detached during maintenance, the machine was stopped below a national highway, near a shared pipeline for communication lines and military cables running along the tunnel's direction. To the right of the tunneling direction was a gas pipeline, buried 1.1m deep, with a horizontal clearance of approximately 2.65m between the gas pipeline and the TBM cutterhead; the clearance between the TBM and the Ningtong Railway's protective fence was 33.4m, placing it outside the railway-related impact zone.

[0038] During tunnel boring machine (TBM) excavation, an abnormal torque was detected on the cutterhead. The machine was stopped on-site, and a pressurized inspection of the cutterhead was conducted. The inspection revealed that the bolts connecting the upper cutterhead flange and the front shield flange were broken, as were the bolts connecting the drive disc and the main bearing, with a gap of approximately 20cm. It was determined that ground reinforcement was necessary before cutterhead repairs were carried out.

[0039] In this embodiment, mortar is first filled into the soil chamber, with approximately 60 cubic meters of mortar injected to reinforce the chamber and prevent subsequent construction from damaging the space within it. The mortar mix ratio is as follows: each cubic meter of mortar requires 40 kg of cement, 350 kg of fly ash, 500 kg of yellow sand, 120 kg of bentonite, and 480 kg of water.

[0040] In this embodiment, pile reinforcement structures are constructed above and in front of the tunnel boring machine cutterhead. These piles are of four types: Pile A is a 0.8m diameter reinforced concrete pile with a vertical clearance of 0.5m between its bottom and the cutterhead, and a horizontal clearance of 0.3m between its core and the cutterhead. Adjacent piles interlock with a clearance of 0.2m, forming a unified structure that acts as a barrier and prevents pile subsidence. Pile B is a 1.0m diameter reinforced concrete pile with fiberglass reinforcement at the bottom 11m to allow for normal tunneling through the pile body after cutterhead repair. The outermost row of piles has a horizontal clearance of 1.75m between its core and the front of the cutterhead, and its bottom extends 6.4m below the top of the cutterhead, interlocking with the surrounding piles with a clearance of 0.2m, forming a unified structure. C piles are 1.0m diameter reinforced concrete piles with a vertical clearance of 0.8m between the pile bottom and the cutterhead. The second row of piles has a horizontal clearance of 0.7m in front of the cutterhead, and the third row has a horizontal clearance of 1.1m in front of the cutterhead. Four B piles are placed on each side of the two rows. Ultimately, a total of 12 A piles, 18 B piles, and 18 C piles are installed.

[0041] In this embodiment, a skylight is reserved in the middle of the pile structure, and a steel casing with a diameter of 1.0m is pre-embedded to enhance ventilation and remove large boulders in front of the cutterhead. It is arranged between the C piles.

[0042] In this embodiment, an 11m*3.4m*0.4m cover plate is constructed at the top of the pile structure to connect to the pile structure below. The cover plate uses C20 threaded steel for the main reinforcement, φ8@400 for the stirrups, and C18 steel bars for the reinforcing bars.

[0043] In this embodiment, an arch support is constructed above the cutterhead, with reinforcing bars anchored 200mm into the pile body, and welded to 3mm sheet metal on top to form the arch support, which is then filled with concrete mortar.

[0044] In this embodiment, the soil reinforcement structure provides a safe and stable working space for subsequent long-term shield tunneling machine open-hole repair operations, and does not have a significant impact on surrounding pipelines.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A soil reinforcement structure for repairing a normal pressure open-chamber cutterhead, characterized in that: The structure includes the tunnel boring machine's soil chamber (1), the cutterhead to be repaired (2), the working space (3), the pile reinforcement structure (4), the cover plate (5), the steel casing (6), the arch support (7), and the densely packed high-strength boulders stratum (8) with soft upper and hard lower layers. The pile reinforcement structure (4) is formed by piles of different diameters and different reinforcements. It forms a reinforcement structure together with the arch support (7) in front of the tunnel boring machine's cutterhead to ensure the stability of the soil in front of and above the cutterhead during repair. The pile reinforcement structure (4) is divided into pile A (401), pile B (402), and pile C (403). Pile A (401) is a reinforced concrete pile with a diameter of 0.8m. The vertical clearance between the bottom of the pile and the tunnel boring machine is 0.5m, and the horizontal clearance between the pile core and the cutterhead is 0.3m. Adjacent piles interlock with a clearance of 0.2m to form a whole, which plays a role in isolation and prevents the pile body from sinking. Pile B (402) is a reinforced concrete pile with a diameter of 1.0m. The bottom 11m is reinforced with fiberglass reinforcement so that the cutterhead can be repaired and the pile body can be excavated normally. The outermost pile core is 1.75m away from the front of the cutterhead. The bottom of the pile enters 6.4m below the top of the cutterhead and interlocks with the surrounding piles. The interlocking amount is 0.2m, forming a whole. C pile (403) is a reinforced concrete pile with a diameter of 1.0m. The vertical net distance between the bottom of the pile and the top of the cutterhead is 0.8m. The core of the second row of piles is 0.4m away from the front of the cutterhead. The core of the third row of piles is 1.1m away from the front of the cutterhead. A B pile (402) is arranged on each side of the two rows of piles, for a total of 4 piles. The B pile (402) and C pile (403) interlock with each other during construction. The interlocking amount is 0.2m. In order to ensure that all piles do not sink, a cover plate (5) is installed on the top of the pile when all piles are formed. This plate connects all piles and prevents the piles from sinking and damaging the working space.

2. The soil reinforcement structure for repairing a normal pressure open-end cutterhead as described in claim 1, characterized in that: The tunnel boring machine's soil chamber (1) is located behind the cutterhead (2) to be repaired, providing working space (3) for cutterhead maintenance.

3. The device for repairing soil reinforcement structure of a normal pressure cutterhead according to claim 1, characterized in that: The cutterhead (2) to be repaired is located in a high-strength boulder stratum (8) with soft upper and hard lower layers. The bolts connecting the cutterhead flange and the front shield flange are broken, and the bolts connecting the drive disc and the main bearing are broken.

4. The apparatus for repairing soil reinforcement structure of a normal pressure cutterhead according to claim 1, wherein: The cover plate (5) is located above the pile-reinforced structure to prevent the pile-reinforced structure from settling. Its dimensions are 11m long * 3.4m wide * 0.4m thick.

5. The apparatus for repairing soil reinforcement structure of a normal pressure cutterhead according to claim 1, wherein: The steel casing (6) is formed by rotary drilling rig and buried as a reserved window for ventilation and removal of large boulders in front of the cutterhead. It is 1m in diameter and 1m above the ground. During construction, it is connected to the cover plate (5) to maintain its stability.

6. The apparatus for repairing soil reinforcement structure of a normal pressure cutterhead according to claim 1, wherein: The arch support (7) uses φ25mm@150 steel bars with a length of 1.5m, which are anchored into the B pile (402) 200mm inside the pile. The other end is placed in the soil outside the shield shell. A square timber with grooves is placed between the shield shell and the steel bar to place the steel bar. A 3mm thick iron sheet is placed on top of the steel bar and welded to the steel bar. The gap between the iron sheet and the soil is filled with mortar.

7. The soil reinforcement structure for repairing a normal pressure open-end cutterhead as described in claim 1, characterized in that: The stratum is soft on top and hard on the bottom, with a high density of high-strength boulders (8). The stratum contains many high-strength, large-diameter boulders, which greatly hinder the tunnel boring machine and damage the cutterhead.

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