Settlement accident treatment method suitable for shield tunnel underneath penetrating pile foundation building

Abstract

The invention relates to the technical field of shield tunnels, and discloses a settlement accident handling method suitable for a shield tunnel underneath penetrating pile foundation building, which comprises the following steps of: reporting and feeding back a dangerous case; emergency disposal, wherein emergency grouting of a building pile foundation and tunneling stopping of the shield tunneling machine are included; dangerous case study and judgment; multidirectional repairing and reinforcing are conducted, specifically, monitoring and measuring are enhanced, supporting and reinforcing are conducted on the building, and supplementary grouting is conducted on a foundation pile foundation; maintaining pressure in a shield tunneling machine cabin; safety evaluation is conducted on the building and the shield tunnel, tunneling is recovered after safety is confirmed, and after a local void area behind the tunnel is ascertained through radar scanning, reinforcing measures of drilling and concrete backfilling are conducted on a bottom plate foundation from the interior of the tunnel. A closed-loop treatment process integrating emergency disposal, reason analysis, structure reinforcement, foundation improvement and source control is constructed, and building top supporting and foundation supplementary grouting are cooperatively carried out to form double guarantees.

Description

Technical Field

[0001] This invention relates to the field of shield tunnel technology, specifically to a method for handling settlement accidents of shield tunnels passing under pile foundation structures. Background Technology

[0002] Constructing multi-level transportation systems within limited urban space has a significant effect on alleviating road congestion. Currently, there are various construction methods for underground transportation tunnels, with the shield tunneling method being widely used in tunnel construction under complex urban conditions due to its advantages of high mechanization, favorable working environment, and minimal traffic impact.

[0003] However, with the continuous development and construction of urban underground space, the available underground space resources are gradually becoming limited. Therefore, subsequent urban shield tunnels will inevitably conflict with surface buildings, villages, factories, municipal roads, bridges, and other structures, making it common for shield tunnels to pass under buildings. Although construction companies implement grouting reinforcement and shield machine excavation control measures, excessive ground and building settlement still frequently leads to accidents such as building cracking, tilting, and even collapse, causing significant economic losses and adverse social impacts.

[0004] In order to minimize economic losses and social impact when a shield tunnel passes under a building and causes an accident, it is necessary to propose a solution for handling settlement accidents of shield tunnels passing under buildings that is easy to construct, scientifically sound, and has minimal impact on the surrounding environment of the original building. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for handling settlement accidents of shield tunnels passing under pile foundation structures, which solves the problem of conflicts between subsequently constructed urban shield tunnels and surface residential buildings, villages, factories, municipal roads, bridges and other structures under conditions of limited underground space resources.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for handling settlement accidents of shield tunnels passing under pile foundation structures, comprising the following steps:

[0007] S1. Emergency reporting and feedback: If cracks or settlement exceeding the limit are found, immediately report to all parties involved in the project. If necessary, evacuate people in and around the building and temporarily close the building within the affected area.

[0008] S2. Emergency response. Emergency response measures mainly include emergency grouting reinforcement of building foundations and stopping tunnel boring machine excavation.

[0009] S3. Risk assessment: Based on the comparative analysis of real-time monitoring data and preset safety thresholds, combined with geological survey data, determine the cause of the accident and formulate a treatment plan that includes specific grouting parameters and support specifications.

[0010] S41. Strengthen monitoring and measurement, deploy static leveling instruments and crack gauges in the area affected by the accident, and adopt a combination of on-site inspection and automated monitoring to improve the monitoring frequency and accuracy.

[0011] S42. Support reinforcement: A thorough re-investigation of the building's structural details was conducted. For existing buildings located above the tunnel boring machine and for beams with cracks, steel pipe columns were used for support. For structurally damaged areas of existing buildings with wall cracks, beam cracks, and column cracks, professional organizations were selected to repair and reinforce them according to requirements.

[0012] S43. Supplementary grouting: For the foundation and subgrade of existing buildings, grouting with sleeve valve pipes is used to reinforce the strata.

[0013] S44. Building inspection and assessment: For existing buildings, assess whether the columns, beams and slabs of the building meet the load-bearing capacity calculation requirements, and whether the safe use of the original structure will not be affected after the emergency is handled.

[0014] S51. Pressure maintenance inside the shield tunneling chamber is determined comprehensively, taking into account overload of ground structures, changes in geological conditions, changes in overburden, changes in water level, monitoring conditions, and summaries of previous tunneling, to ensure smooth mud circulation inside the shield tunneling chamber.

[0015] S52. Safety assessment of shield tunnels: Based on the results of shield tunnel deformation and back cavity monitoring, as well as the overall inspection and assessment of the shield machine, confirm whether the requirements are met. If not, grouting reinforcement or steel ring treatment measures should be carried out in the cavity area behind the segments.

[0016] S6. After the tunnel boring machine passes through the pile foundation of the building, the surface settlement stability monitoring period shall not be less than one week. After the assessment confirms that all monitoring indicators are stable within the preset safety value range, the support structure shall be removed and the emergency response shall be completed.

[0017] Preferably, emergency grouting reinforcement of building foundations adopts sleeve valve pipe grouting. The grouting range is the pile foundation of the building foundation that is in danger due to settlement. The reinforcement depth extends to 2m above the tunnel boring machine to prevent the foundation of high-rise buildings from sinking further and ensure that the strata tend to be stable.

[0018] Preferably, the monitoring and measurement are mainly divided into two aspects: buildings and shield tunnels. The monitoring range is the main impact area and the secondary and general impact areas. The main impact area is 50m to the left and right of the tunnel direction, and the secondary and general impact area is 50-90m. The monitoring items are divided into building settlement, track surface and roadbed settlement, surface settlement, groundwater level, deep and layered settlement, crack investigation and monitoring, and tunnel segment lining ring monitoring.

[0019] Preferably, the reinforcement of cracks in the beam should be carried out after the supports are in place.

[0020] Preferably, the temporary support should be erected by setting up double rows of steel columns above the ground where the steel plates are laid, with a truss structure between the columns to increase stability, and jacks placed on top of the columns to apply a certain force to tightly attach the steel beams to the beam body.

[0021] Preferably, the reinforcement treatment for beam cracks adopts different measures according to the crack width. For micro cracks with a width of less than 0.2 mm, the surface repair method is used; when the crack is wider, reaching 0.15 mm to 0.3 mm, the slotting and filling method is used; when the crack is narrow and deep, the epoxy resin grout injection method can be used for treatment.

[0022] Preferably, the supplementary grouting depth range is from 2m above the tunnel boring machine to the foundation platform of the high-rise building on the ground, and the plane range is 5m on each side of the tunnel boring machine edge and 5m beyond the building foundation in the tunnel boring machine direction; the grout is mainly composed of 0.8:1 cement single liquid grout with bentonite and admixtures, supplemented by 1:1 cement and water glass double liquid grout.

[0023] Preferably, the pressure maintenance inside the shield tunnel chamber adopts a micro-overpressure mode, which involves injecting high-viscosity slurry into the chamber to increase the slurry pressure by 0.1 Bar.

[0024] Preferably, the safety assessment of shield tunnels mainly includes: monitoring of arch subsidence and tunnel convergence; using radar scanning and hole inspection to show local voids behind the segments; and assessing the overall condition of the machine by verifying whether the operating parameters of key components of the shield machine are within the normal operating range set by the manufacturer.

[0025] Preferably, the grouting reinforcement treatment measures in S52 are as follows: radial grouting is performed in the void area behind the shield tunnel segments, using a retreating grouting process. The grouting uses a two-liquid grout with a cement grout and water glass volume ratio of 1:1, and the cement grout water-cement ratio is preferably 0.8:1 to 1:1. The shield tunneling begins radar scanning monitoring to determine the void area every 3 to 5 rings, and grouting reinforcement is performed within this area. The drill rod and drill bit diameter is 42mm. The drill rod is lifted while grouting, with each step preferably 0.2 to 0.3m, and the grouting is pulled back at a uniform speed. The length of the grouting pipe exposed is 0.5 to 1.0m.

[0026] This invention provides a method for handling settlement accidents of shield tunnels passing under pile foundation structures.

[0027] It has the following beneficial effects:

[0028] 1. This invention combines the reinforcement of the building structure with the grouting reinforcement of the foundation soil, constructing a dual safety guarantee system for the superstructure and the substructure. By temporarily supporting and repairing cracks in the damaged beams, the building structure is directly stabilized; simultaneously, emergency grouting and supplementary grouting techniques reinforce the soil around the pile foundation and above the tunnel, fundamentally improving the foundation conditions of the building, effectively preventing the continued development of settlement, and resulting in a more thorough and reliable treatment effect.

[0029] 2. This invention not only addresses the existing settlement problem but also proactively eliminates safety hazards through meticulous assessment and repair of the tunnel itself. By controlling disturbances at the source using micro-overpressure tunneling technology and identifying localized voids behind tunnel segments using radar scanning, along with reinforcement techniques involving drilling and grouting from within the shield tunnel, the tunnel structure is effectively repaired. This ensures the long-term stability and safety of the tunnel and prevents similar risks from recurring.

[0030] 3. This invention establishes a systematic closed-loop processing flow, from hazard reporting, emergency response, cause analysis, multi-faceted repair and reinforcement to resumption of tunneling, thus standardizing and proceduralizing the accident handling process. This method changes the previous fragmented and passive response model, ensuring coordinated linkage of key links such as problem analysis, structural support, foundation reinforcement, and tunneling parameter adjustment through a complete technical logic chain, thereby achieving comprehensive, efficient, and scientific risk management of settlement accidents. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the accident handling process of the present invention;

[0032] Figure 2 This is a schematic diagram of the emergency grouting plan for the building foundation and subgrade according to the present invention;

[0033] Figure 3 This is a vertical schematic diagram of emergency grouting for building foundations and subgrades according to the present invention;

[0034] Figure 4 This is a schematic diagram of the temporary steel support for the beam according to the present invention;

[0035] Figure 5 This is a schematic diagram of the grouting reinforcement of the building foundation and ground according to the present invention;

[0036] Figure 6 This is a schematic cross-sectional view of the grouting reinforcement of the building foundation and ground according to the present invention;

[0037] Figure 7 This is a schematic cross-sectional view of the shield tunnel grouting reinforcement method according to the present invention.

[0038] Among them, 1. Existing buildings; 11. Pile foundations; 12. Existing beams; 13. Foundation caps; 2. Tunnel boring machines; 31. Steel pipe columns; 32. Steel plates; 33. Trusses; 34. Jacks; 35. Steel beams; 4. Sleeve valve pipes; 5. Void zones; 6. Segments; 7. Grouting pipes. Detailed Implementation

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Please see the appendix Figure 1 - Appendix Figure 7 This invention provides a method for handling settlement accidents of shield tunnels passing under pile foundation structures, the method comprising the following steps:

[0041] S1. Emergency reporting and feedback: If cracks or settlement exceeding the limit are found, immediately report to all parties involved in the project. If necessary, evacuate people in and around the building and temporarily close the building within the affected area.

[0042] S2. Emergency response measures mainly include emergency grouting reinforcement of the building foundation and stopping tunnel boring machine 2.

[0043] S3. Risk assessment: Based on the comparative analysis of real-time monitoring data and preset safety thresholds, combined with geological survey data, determine the cause of the accident and formulate a treatment plan that includes specific grouting parameters and support specifications.

[0044] S41. Strengthen monitoring and measurement, deploy static leveling instruments and crack gauges in the area affected by the accident, and adopt a combination of on-site inspection and automated monitoring to improve the monitoring frequency and accuracy.

[0045] S42. Support reinforcement: A thorough re-investigation of the building's structural details was conducted. For the existing building 1 located above the tunnel boring machine 2 and for the beams with cracks, steel pipe columns 31 were used for support. For the structurally damaged areas of the existing building 1 with wall cracks, beam cracks, and column cracks, a professional organization was selected to repair and reinforce them as required.

[0046] S43. Supplementary grouting: For the foundation and subgrade of the existing building 1, grouting is carried out using sleeve valve pipe 4 to reinforce the stratum.

[0047] S44. Building inspection and assessment: For existing building 1, verify whether the columns, beams and slabs of existing building 1 meet the load-bearing capacity calculation requirements, and whether the safe use of the original structure will not be affected after the emergency is handled.

[0048] S51. Pressure maintenance in the second chamber of the tunnel boring machine is determined by taking into account the overload of ground buildings and structures, changes in geological conditions, changes in overburden, changes in water level, monitoring conditions, and the summary of previous tunneling, in order to maintain smooth slurry circulation in the second chamber of the tunnel boring machine.

[0049] S52. Safety assessment of shield tunnel: Based on the deformation monitoring of shield tunnel segment 6, void detection and overall inspection of shield machine 2, confirm whether the requirements are met. If not, grouting reinforcement or steel ring treatment measures should be carried out in the tunnel.

[0050] S6. After tunneling through the building's pile foundation, the surface settlement stability monitoring period shall be no less than one week. After the assessment confirms that all monitoring indicators are stable within the preset safety value range, the support structure shall be dismantled, and the emergency response shall be completed.

[0051] Furthermore, by combining immediate risk control (S1 and S2), technical cause analysis (S3), targeted repair (S4), tunneling source adjustment (S5), and final safety confirmation (S6), a closed-loop processing flow is formed, ensuring the comprehensiveness, scientific nature, and safety of accident handling, and avoiding potential risk omissions and secondary disasters that may result from traditional fragmented handling methods.

[0052] The emergency grouting reinforcement of the building foundation adopts sleeve valve pipe 4 for grouting. The grouting range is the pile foundation 11 of the building foundation that is in danger due to settlement. The reinforcement depth extends to 2m above the shield machine 2 to prevent the pile foundation 11 of the high-rise building from sinking further and to ensure that the stratum tends to be stable.

[0053] Furthermore, grouting is carried out using sleeve valve pipe 4. Its advantage is that segmented and repeated grouting can be achieved through the open and closed grout outlet holes on the pipe wall. Precise supplementary grouting operations can be carried out according to the settlement of the strata. The reinforcement depth is set at 2m above the shield machine 2, aiming to form a soil reinforcement arch with sufficient thickness and strength. This reinforcement arch can effectively bear and diffuse the load of the superstructure foundation and transfer it to both sides of the shield tunnel, thereby isolating the direct impact of tunnel excavation on the building foundation. It is a key emergency measure to control uneven settlement.

[0054] The monitoring and measurement are mainly divided into two aspects: building and shield tunnel monitoring. The monitoring range is the main impact area and the secondary and general impact areas. The main impact area is 50m on the left and right sides along the tunnel direction, and the secondary and general impact areas are 50-90m. The monitoring items are: settlement of existing buildings 1, surface settlement, groundwater level, deep and layered settlement, crack investigation and monitoring, and ring monitoring of tunnel segment 6 lining.

[0055] Furthermore, the regional monitoring strategy optimizes resource allocation by concentrating high-frequency, high-precision automated monitoring equipment in areas with the highest settlement risk, while conducting regular inspections of secondary affected areas. This approach ensures both focus and comprehensive coverage. Deep and layered settlement monitoring is particularly important, as it reveals the compression deformation patterns of soil at different depths. This provides direct data support for determining whether settlement originates from shallow soil disturbance or insufficient deep bearing capacity, thereby guiding the optimization of grouting schemes.

[0056] The reinforcement of cracks in the beam should be carried out after the supports are in place;

[0057] Furthermore, if cracks are repaired directly without effective support, the beam will still be under stress and deformation. This will not only fail to prevent the cracks from continuing to develop, but the newly added material may also crack and fall off due to continuous stress, rendering the repair ineffective. It is necessary to first transfer the load on the beam through a support structure to bring it to a stable or stress-released state before carrying out permanent crack repair to ensure the longevity and reliability of the repair effect.

[0058] To erect a temporary support structure 3, double rows of steel columns need to be set up above the ground where steel plates 32 are laid. A truss 33 is set up between the columns to increase stability. A jack 34 is placed on top of the columns. The jack 34 applies a certain force to tightly attach the steel beam 35 to the existing beam 12 of the building.

[0059] Furthermore, steel plates 32 are laid on the ground to increase the load-bearing area and prevent point damage to the ground. The double rows of steel columns and trusses 33 together form a load-bearing frame with high rigidity and stability. The jacks 34 set on the top of the columns serve two purposes: first, to adjust the height and ensure that the upper steel beams 35 are in close contact with the bottom surface of the existing beams 12 without gaps; second, to apply a pre-jacking force to the support system, so that it enters the working state in advance and actively bears part of the beam load, preventing new settlement before the load is completely transferred.

[0060] When beams crack, different measures are used for reinforcement depending on the crack width. For micro-cracks less than 0.2 mm wide, surface repair is used; for cracks wider than 0.15 mm to 0.3 mm, slotting and filling is used; and for cracks that are both narrow and deep, epoxy resin grout can be injected for treatment.

[0061] Furthermore, for micro-cracks less than 0.2mm wide, their impact on structural load-bearing capacity is relatively small. Surface repair methods, such as applying epoxy putty or penetrating waterproofing agent, can effectively seal the cracks and prevent the intrusion of moisture and harmful media. For wider cracks, V-shaped or U-shaped grooves need to be chiseled along the cracks and then filled with high-strength materials such as epoxy mortar to restore the integrity of the component. For fine and deep internal cracks, pressure grouting technology must be used to inject low-viscosity epoxy resin deep into the cracks, allowing them to re-bond into a whole, thereby truly restoring the load-bearing capacity of the component.

[0062] The supplementary grouting depth range is from 2m above the shield machine 2 to the foundation platform 13 of the high-rise building on the ground. The planar range is 5m on each side of the shield edge and 5m beyond the building foundation in the shield tunneling direction. The grout is mainly composed of 0.8:1 cement single liquid grout with bentonite and admixtures, supplemented by 1:1 cement and water glass double liquid grout.

[0063] Furthermore, the grouting range was defined to create a complete, three-dimensional reinforced soil mass between the building foundation and the tunnel. The choice of grout mix ratio reflects a synergistic effect: a single-component cement grout is used for large-scale filling and penetration, utilizing the suspension properties of bentonite and the water-reducing and retarding effects of admixtures to improve the grout's fluidity and injectability; in localized areas encountering water inrush or requiring rapid sealing, a two-component cement and water glass grout is used, utilizing its instantaneous solidification characteristics to achieve rapid leak sealing and emergency response.

[0064] The pressure maintenance in the second chamber of the tunnel boring machine adopts a micro-overpressure mode, which injects high-viscosity slurry into the chamber to increase the slurry pressure by 0.1 Bar.

[0065] Furthermore, increasing the slurry pressure by only 0.1 Bar is a refined control method aimed at balancing the stability of the excavation face and preventing excessive disturbance to the strata. This small overpressure is sufficient to compensate for the stress reduction caused by the superstructure load, effectively resisting the collapse of the soil into the excavation face, thereby controlling surface settlement. In conjunction with the use of high-viscosity slurry, it helps to form a dense and low-permeability mud film on the excavation face. This mud film is key to maintaining stable pressure within the chamber and preventing pressure loss.

[0066] The safety assessment of the tunnel boring machine (TBM) mainly includes: ① deformation monitoring of segment 6; ② radar scanning detection; ③ overall assessment of TBM 2. The overall condition of the TBM 2 is assessed by verifying whether the operating parameters of its key components are within the normal operating range set by the manufacturer.

[0067] Furthermore, tunnel deformation monitoring provides surface data that directly reflects the safety status of the tunnel structure. Secondly, radar scanning confirms the presence of localized voids 5 behind segment 6, a major hidden danger leading to later deformation and continuous settlement of the shield tunnel segment 6. Finally, the overall assessment of the tunnel boring machine 2 can rule out the possibility of construction quality problems caused by equipment malfunctions such as insufficient pressure in the synchronous grouting system, ensuring the reliability of subsequent tunneling.

[0068] Preferably, the grouting reinforcement treatment measures in S52 are as follows: Based on the radar scanning monitoring results, the range of the void zone 5 behind the shield tunnel segment 6 is determined. Radial grouting is then performed within the void zone 5 range behind the shield tunnel segment 6, using a retreating grouting process. The grout uses a two-component grout with a cement grout and water glass volume ratio of 1:1. The cement grout water-cement ratio should be 0.8:1 to 1:1. Radar scanning monitoring is initiated every 3 to 5 rings of shield tunneling to determine the range of the void zone 5. Grouting reinforcement is performed promptly based on the detection results. The drill rod and drill bit diameter is 42mm. Grouting is performed while simultaneously lifting the drill rod, with each step preferably 0.2 to 0.3m, and the grouting is withdrawn at a uniform speed. The grouting pipe 7 is exposed for 0.5 to 1.0m.

[0069] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their likenesses.

Claims

1. A method for handling settlement accidents of shield tunnels passing under pile foundation structures, characterized in that, Includes the following steps: S1. Emergency reporting and feedback: When building cracks or settlement exceeding limits are discovered, immediately report to all parties involved in the project. If necessary, evacuate people inside and near the building and temporarily close the building within the affected area. S2. Emergency response. Emergency response measures mainly include emergency grouting reinforcement of building foundations and stopping tunnel boring machine excavation. S3. Risk assessment: Based on the comparative analysis of real-time monitoring data and preset safety thresholds, combined with geological survey data, determine the cause of the accident and formulate a treatment plan that includes specific grouting parameters and support specifications. S41. Strengthen monitoring and measurement, deploy static leveling instruments and crack gauges in the area affected by the accident, and adopt a combination of on-site inspection and automated monitoring to improve the monitoring frequency and accuracy. S42. Support reinforcement: Conduct a thorough re-investigation of the building's structural details. For the existing building (1) located above the shield tunnel and for the beams with cracks, steel pipe columns (31) were used for support. For the structurally damaged parts of the existing building (1) with wall cracks, beam cracks, and column cracks, professional institutions were selected to repair and reinforce them as required. S43. Supplementary grouting: For the foundation and subgrade of the existing building (1), grouting with sleeve valve pipe (4) is used to reinforce the stratum. S44. Building inspection and assessment: For existing buildings (1), verify whether the columns, beams and slabs of the building meet the load-bearing capacity verification requirements, and whether the safety of the original structure will not be affected after the emergency is handled. S51. The internal pressure of the tunnel boring machine is determined by taking into account the overload of ground buildings and structures, changes in geological conditions, changes in soil cover, changes in water level, monitoring conditions, and the summary of previous tunneling, in order to maintain smooth circulation inside the tunnel boring machine chamber. S52. Safety assessment of shield tunnels: Based on the monitoring results of shield tunnel segment deformation and back cavity, as well as the overall inspection and assessment of the shield machine, confirm whether the requirements are met. If not, grouting reinforcement or steel ring treatment measures should be carried out inside the tunnel. S6. After the tunnel boring machine passes through the pile foundation of the building, the surface settlement stability monitoring period shall not be less than one week. After the assessment confirms that all monitoring indicators are stable within the preset safety value range, the support structure shall be removed and the emergency response shall be completed.

2. The method for handling settlement accidents of shield tunnels passing under pile foundation structures according to claim 1, characterized in that, The emergency grouting reinforcement of the building foundation adopts sleeve valve pipe (4) grouting. The grouting range is the pile foundation (11) of the building foundation that is in danger due to settlement. The reinforcement depth extends to 2m above the shield machine to prevent the foundation of high-rise buildings from sinking further and ensure that the stratum tends to be stable.

3. The method for handling settlement accidents of shield tunnels passing under pile foundation structures according to claim 1, characterized in that, The monitoring and measurement are mainly divided into two aspects: buildings and shield tunnels. The monitoring range is the main impact area and the secondary and general impact areas. The main impact area is 50m to the left and right of the tunnel direction, and the secondary and general impact areas are 50-90m. The monitoring items are divided into building settlement, track surface and roadbed settlement, surface settlement, groundwater level, deep and layered settlement, crack investigation and monitoring, and tunnel segment (6) lining ring monitoring.

4. A method for handling settlement accidents of shield tunnels passing under pile foundation structures, as described in claim 1, characterized in that, The reinforcement of cracks in the beam should be carried out after the supports are in place.

5. A method for handling settlement accidents of shield tunnels passing under pile foundation structures, as described in claim 1, characterized in that, To erect temporary supports, double rows of steel columns need to be set up above the ground where steel plates (32) are laid. A truss (33) is set up between the columns to increase stability. A jack (34) is placed on top of the columns. The jack (34) applies a certain force to tightly attach the steel frame (35) structure to the beam.

6. A method for handling settlement accidents of shield tunnels passing under pile foundation structures, as described in claim 1, characterized in that, When beams crack, different measures are used for reinforcement depending on the crack width. For micro-cracks less than 0.2 mm wide, surface repair is used; for cracks wider than 0.15 mm to 0.3 mm, slotting and filling is used; and for cracks that are both narrow and deep, epoxy resin grout can be injected for treatment.

7. A method for handling settlement accidents of shield tunnels passing under pile foundation structures, as described in claim 1, characterized in that, The supplementary grouting depth range is from 2m above the shield machine (2) to the foundation platform (13) of the high-rise building on the ground. The plane range is 5m on each side of the shield edge and 5m beyond the building foundation in the shield excavation direction. The grout is mainly composed of 0.8:1 cement single liquid grout with bentonite and admixtures, supplemented by 1:1 cement and water glass double liquid grout.

8. A method for handling settlement accidents of shield tunnels passing under pile foundation structures, as described in claim 1, characterized in that, The pressure maintenance inside the tunnel boring machine chamber adopts a micro-overpressure mode, which injects high-viscosity slurry into the chamber to increase the slurry pressure by 0.1 Bar.

9. A method for handling settlement accidents of shield tunnels passing under pile foundation structures, as described in claim 1, characterized in that, The safety assessment of shield tunnels mainly includes: monitoring the subsidence of the arch and the convergence of the tunnel; using radar scanning and hole inspection to show whether there are local voids (5) behind the segments (6); and assessing the overall status of the machine by checking whether the operating parameters of the key components of the shield machine (2) are within the normal operating range set by the manufacturer.

10. A method for handling settlement accidents of shield tunnels passing under pile foundation structures, as described in claim 1, characterized in that, The specific measures for grouting reinforcement in S52 are as follows: Based on the radar scanning monitoring results, the range of the void zone 5 behind the shield tunnel segment 6 is determined. Radial grouting is then performed within the void zone 5 behind the shield tunnel segment 6, using a retreating grouting process. The grouting uses a two-liquid grout with a cement grout and water glass volume ratio of 1:

1. The water-cement ratio of the cement grout should be 0.8:1 to 1:

1. Radar scanning monitoring is started every 3 to 5 rings of shield tunneling to determine the range of the void zone 5. Grouting reinforcement is performed in a timely manner based on the detection results. The diameter of the drill rod and drill bit is 42mm. The drill rod is lifted while grouting, with each step preferably 0.2 to 0.3m. The grouting is pulled back at a uniform speed, and the length of the grouting pipe 7 exposed is 0.5 to 1.0m.

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