Design method and structure of multi-layer composite plate reinforced shield tunnel structure

Abstract

The invention discloses a design method of a multi-layer composite plate reinforced shield tunnel structure and the structure, and aims to improve the bearing capacity and the structural stability of tunnel segments. According to the method, curve-shaped FRP profiles with the thickness of 6-10 mm are used for adjacent blocks and adjacent pipe pieces without cracks, curve-shaped FRP profiles with the thickness of 10-15 mm are used for the tops of a plurality of transverse cracks, and the multiple layers of FRP profiles are pasted through structural adhesives in a staggered joint mode to be tightly combined with the tunnel pipe pieces, so that cracking deformation is reduced, and pipe piece cracks are repaired; considering the construction convenience and the reinforcement effect optimization, the invention has the advantages of light weight, high strength, corrosion resistance and the like, and is easy to process and install. The reinforcing method is high in adaptability, can be applied to shield tunnels of different types and geological conditions, and can delay the crack development speed, improve the pipeline bearing capacity, improve the overall performance of the tunnel and prolong the service life of the tunnel.

Description

Technical Field

[0001] The present invention relates to the technical field of shield tunnel reinforcement structure design, in particular to a design method and structure for reinforcing a shield tunnel structure with a multi-layer composite plate. Background Art

[0002] With the acceleration of the urbanization process, the development of underground space has increasingly become an important means to relieve the ground traffic pressure in cities and optimize the urban spatial layout. As an important form of underground traffic construction, shield tunnels are widely used in projects such as subways and municipal utility tunnels due to their advantages such as fast construction speed and little impact on the ground environment. However, with the increase in the tunnel operation time, various problems gradually emerge in the tunnel segments, such as cracks, spalling, deformation, etc., which seriously threaten the safety and stability of the tunnel.

[0003] The patent with the publication number CN117852144A discloses a design method for a laminated reinforced shield tunnel lining structure based on the failure mode. This method is based on the failure mechanism of the integral ring experiment of the laminated reinforced shield tunnel, envelopes and considers the stress development history of the shield tunnel segments, calculates the height of the compression zone and the strain variable of the concrete in the compression zone of the cross-section under the incremental load based on the stress development of different cross-sections, and solves the problem that the stress history of the in-service shield tunnel cannot be measured; solves the problem that the stiffness of the non-symmetric cross-section of the shield tunnel after lamination is different under the action of positive and negative bending moments by iterative calculation to match the sign of the cross-section moment and the sign of the stiffness; obtains the initial deformation of the shield tunnel before reinforcement through three-dimensional laser scanning and takes the initial deformation into account in the calculation of the bearing capacity and stiffness of the laminated reinforced shield tunnel.

[0004] However, this patent has the following defects: Although the bearing capacity and stiffness of the shield tunnel are calculated, no measures are taken to directly enhance the local or overall strength of the tunnel lining. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art, and proposes a design method and structure for reinforcing a shield tunnel structure with a multi-layer composite plate.

[0006] The present invention provides the following technical solutions: A design method for a multi-layer composite plate reinforced shield tunnel structure, comprising the following steps:

[0007] Step S1: Seal the manhole, then mark the installation area in the area to be reinforced of the shield tunnel, clean and treat the surface of the tunnel segment to ensure that there are no sundries, oil stains, etc., so as to ensure the close combination of the multi-layer curved FRP profiles and the tunnel segment.

[0008] Step S2: Install multiple layers of curved FRP profiles on the inner wall of the tunnel segment. The outer arc surface of the multiple layers of curved FRP profiles is covered with structural adhesive not less than 5 mm thick, and they are installed closely against the tunnel segment. The adjacent multiple layers of curved FRP profiles are aligned at the joints and glued, and the multiple layers of curved FRP profiles are pasted with staggered joints through the structural adhesive.

[0009] Step S3: The structural adhesive solidifies, and the multiple layers of curved FRP profiles are fixed on the inner wall of the tunnel segment.

[0010] Preferably, the specific steps of step S1 include:

[0011] S1.1: Prepare suitable plugging materials, such as fireproof sealant, steel plates, bolts, etc., to ensure that the materials meet the safety standards and design requirements;

[0012] S1.2: Select a suitable plugging method according to the size and shape of the manhole; for small manholes, the sealant can be directly used for filling; for large manholes or manholes that need to bear greater pressure, the method of using steel plates for reinforcement and bolts for fastening is required for plugging;

[0013] S1.3: After the plugging is completed, the sealing performance of the plugging area should be checked to ensure that there is no air leakage or water leakage, so as to ensure the independence of the construction environment;

[0014] S1.4: Use measuring tools such as total station and rangefinder to accurately measure the specific position and size of the area to be reinforced;

[0015] S1.5: According to the measurement results, use obvious markers such as paint and tape on the tunnel segment to mark the boundary line of the installation area; the marks should be clear, accurate and easy to identify;

[0016] S1.6: Use tools such as brooms and vacuum cleaners to remove dust, sand and other debris on the surface of the tunnel segment. For stubborn oil stains, rust and other stains, chemical cleaning agents or high-pressure water guns can be used for deep cleaning; pay attention to using suitable cleaning agents to avoid corrosion of the tunnel segment;

[0017] S1.7: After the cleaning is completed, the surface of the tunnel segment is treated as needed to improve its bonding force with the multiple layers of curved FRP profiles.

[0018] Preferably, the specific steps of step S2 include:

[0019] S2.1: Design the structure of the multiple layers of curved FRP profiles. This structure is composed of multiple layers of FRP materials pasted with staggered joints. Each layer of FRP material is integrally formed. The size of the outermost layer of FRP is equivalent to the inner arc size of the shield tunnel segment, and it is used to closely fit the inner arc surface of the shield tunnel segment;

[0020] S2.2: Determine the size and quantity of the multi-layer curved FRP profiles. Based on the size of the shield tunnel segment to be strengthened and the strengthening requirements, calculate and design the specific size of the multi-layer curved FRP profiles and the quantity of FRP profiles required to ensure the strengthening effect; Prepare the FRP profiles using the forming processes of FRP materials, such as prepreg, pultrusion, or winding, etc., to prepare FRP profiles that meet the design requirements;

[0021] S2.3: Select a structural adhesive material that meets the requirements to ensure its good stability and strength; Conduct surface treatment as needed: roughen the area to be repaired or bonded, and then clean it with a cleaning agent. Prepare the adhesive according to a certain ratio and use it up within the specified operation time limit;

[0022] S2.4: Stagger the joints of several layers of FRP profiles and paste them together to form multi-layer curved FRP profiles. Coat the outer arc surface of the prepared multi-layer curved FRP profiles with a structural adhesive with a thickness of not less than 5 mm. Then, attach the outer arc surface of the multi-layer curved FRP profiles to the inner arc surface of the shield tunnel segment, ensuring no bubbles and voids. Use appropriate tools such as clamps and support frames to temporarily fix the multi-layer curved FRP profiles to prevent displacement before the structural adhesive solidifies;

[0023] S2.5: The structural adhesive solidifies, and the multi-layer curved FRP profiles are fixed to the inner wall of the tunnel segment;

[0024] S2.6: Through simulation experiments or actual use, verify the effect of strengthening the shield tunnel structure with multi-layer curved FRP profiles, including indicators such as strengthening strength, durability, and impermeability.

[0025] Preferably, the specific steps of step S2.6 further include:

[0026] Use computer simulation software to conduct stress analysis on the strengthened structure and optimize the design according to the results; In the stress analysis and optimization steps, introduce multi-physics field coupling analysis to more comprehensively evaluate the stress situation of the structure;

[0027] The bearing capacity of the tunnel segment strengthened with multi-layer curved FRP profiles should be checked and calculated according to the following formula requirements:

[0028]

[0029] In the formula: σ represents the normal stress, which is the stress component perpendicular to the cross-section. According to the different directions of the load, the normal stress is further divided into tensile stress and compressive stress; Tensile stress is positive, and compressive stress is negative; τ represents the shear stress, which is the stress component parallel to the cross-section. Shear stress usually appears in shear deformation or torsional deformation, σ x 、σ y 、σ zare the normal stresses in the x, y, and z directions, respectively, and τ xy , τ yz , τ zx are the shear stresses on the corresponding planes, respectively. The stress distribution and deformation of the structure under different loads can be calculated, providing a basis for the design and optimization of the structure.

[0030] Preferably, the step S3 further includes:

[0031] S3.1: After gluing, the residues on the pipe wall should be cleaned in time to prevent the residues from affecting the subsequent construction.

[0032] S3.2: After gluing, the gluing effect should be detected, including the strength, density of the glue, and the bonding strength with the tunnel segment, etc.

[0033] Preferably, in the design method of the multi-layer composite plate for strengthening the shield tunnel structure: for adjacent blocks and adjacent segments without cracks, the curved FRP profiles with a thickness of 6 - 10 mm are used; for the top with multiple transverse cracks that have occurred, the curved FRP profiles with a thickness of 10 - 15 mm are used for staggered multi-layer pasting.

[0034] Preferably, the surface of the multi-layer curved FRP profile is coated with an anti-corrosion layer to extend its service life in the underground environment.

[0035] The structure applying the design method of the above multi-layer composite plate for strengthening the shield tunnel structure includes tunnel segments, anchor bolts, manholes, and multi-layer curved FRP profiles;

[0036] The tunnel segments are fixed on the inner wall of the shield tunnel. Manholes are provided on the outer wall of the tunnel segments, and anchor bolts connected by bolts are provided on the inner wall of the tunnel segments;

[0037] Six tunnel segments are spliced into a segment ring, and the segment ring is tightly attached to the inside of the tunnel. The anchor bolts on the outer walls on both sides of the tunnel segments are connected by bolts to connect adjacent tunnel segments, and then they are connected and fixed through the bolts inside the manholes;

[0038] The inner wall of the tunnel segment is provided with multi-layer curved FRP profiles, and the multi-layer curved FRP profiles are pasted with structural adhesive in a staggered manner by multiple single-layer FRP profiles;

[0039] The multi-layer curved FRP profiles are tightly attached to the inner wall of the tunnel segment. The flanges on both sides are coated with structural adhesive and fixed on the inner wall of the tunnel segment, and the multi-layer curved FRP profiles are pasted in a staggered manner on the inner wall of the tunnel segment.

[0040] Preferably, a roadbed is further provided on the inner wall of the tunnel segment, and a bracket is provided on the outer wall of the roadbed; the roadbed has functions such as conducting load, preventing transverse and longitudinal movement of the track, and draining accumulated water, and the bracket supports and fixes the roadbed and can absorb a certain degree of impact force.

[0041] Advantages of the present invention:

[0042] 1. The design method and structure of the shield tunnel structure reinforced by stagger-joint pasting of multi-layer curved FRP profiles proposed by the present invention significantly improve the bearing capacity and structural stability of the tunnel segment. By adopting the method of closely combining multi-layer curved FRP profiles with the tunnel segment and combining the reinforcement measures of stagger-joint pasting and structural adhesive pasting, problems such as cracking and deformation of the tunnel segment caused by factors such as geological changes, construction errors or operating loads are significantly reduced.

[0043] 2. The shield tunnel structure reinforced by stagger-joint pasting of multi-layer curved FRP profiles of the present invention fully considers the optimization of construction convenience and reinforcement effect in design. FRP profiles have the advantages of light weight, high strength, corrosion resistance, etc., and are easy to process and install. Through standardized design and modular construction, the construction period can be significantly shortened and the construction cost can be reduced. At the same time, the multi-layer FRP is bonded by a stagger-joint structural adhesive, which further enhances the stiffness and durability of the structure and ensures the long-term and reliable reinforcement effect.

[0044] 3. The reinforcement method of the present invention can effectively deal with various problems that may occur in the operation process of the tunnel segment, improve the overall performance and service life of the tunnel. At the same time, this reinforcement method is applicable to different types of shield tunnels and different geological conditions, and has strong adaptability and flexibility. Description of the drawings

[0045] Figure 1 It is a flowchart of a design method of a shield tunnel structure reinforced by a multi-layer composite plate of the present invention;

[0046] Figure 2 It is a schematic diagram of the pre-installation process in the present invention;

[0047] Figure 3 It is a schematic diagram of the middle and late installation processes in the present invention;

[0048] Figure 4 It is an overall schematic diagram of a shield tunnel structure reinforced by a multi-layer composite plate of the present invention;

[0049] Figure 5 It is an installation schematic diagram of a tunnel segment and stagger-joint pasted multi-layer curved FRP profiles in the present invention;

[0050] Figure 6 It is a schematic diagram of a manhole of a tunnel segment in the present invention;

[0051] Figure 7 Schematic diagram of multi-layer curved FRP profiles pasted with staggered joints in the present invention;

[0052] Figure 8 Schematic diagram of single-layer curved FRP profile in the present invention.

[0053] Reference numerals: 101, tunnel segment; 102, anchor bolt; 103, manhole; 201, multi-layer curved FRP profile; 301, bracket; 302, roadbed. Specific embodiments

[0054] To make the above objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings of the specification.

[0055] As Figure 1-8 shown, a design method for a shield tunnel structure reinforced with a multi-layer composite plate includes the following steps:

[0056] Step S1: Seal the manhole 103, then mark the installation area in the area to be reinforced in the shield tunnel, clean and treat the surface of the tunnel segment 101 to ensure no debris, oil stains, etc., so as to ensure the close combination of the multi-layer curved FRP profile 201 and the tunnel segment 101;

[0057] The specific steps include:

[0058] S1.1: Prepare suitable sealing materials, such as fireproof sealant, steel plates, bolts, etc., to ensure that the materials meet the safety standards and design requirements;

[0059] S1.2: Select a suitable sealing method according to the size and shape of the manhole 103; for a small manhole 103, the sealant can be directly used for filling; for a large manhole 103 or a manhole 103 that needs to withstand greater pressure, the method of using steel plate reinforcement and bolt fastening for sealing is required;

[0060] S1.3: After the sealing is completed, the sealing performance of the sealed area should be checked to ensure no air leakage or water leakage, so as to ensure the independence of the construction environment;

[0061] S1.4: Use measuring tools such as total station and rangefinder to accurately measure the specific position and size of the area to be reinforced;

[0062] S1.5: According to the measurement results, use obvious markers such as paint and tape on the tunnel segment 101 to mark the boundary line of the installation area; the marks should be clear, accurate and easy to identify;

[0063] S1.6: Use tools such as brooms and vacuum cleaners to remove dust, sand and other debris on the surface of the tunnel segment 101. For stubborn oil stains, rust, etc., chemical cleaning agents or high-pressure water guns can be used for in-depth cleaning. Pay attention to using appropriate cleaning agents to avoid corrosion of the tunnel segment 101;

[0064] S1.7: After cleaning, treat the surface of the tunnel segment 101 as needed to improve its bonding force with the multi-layer curved FRP profile 201;

[0065] Step S2: Install the multi-layer curved FRP profile 201 on the inner wall of the tunnel segment 101. The outer arc surface of the multi-layer curved FRP profile 201 is covered with structural adhesive not less than 5 mm thick and is installed closely against the tunnel segment 101. Adjacent multi-layer curved FRP profiles 201 are aligned at the joints for gluing, and the multi-layer curved FRP profiles 201 are pasted with staggered joints through the structural adhesive;

[0066] The specific steps include:

[0067] S2.1: Design the structure of the multi-layer curved FRP profile 201. This structure is pasted by multi-layers of FRP materials, and each layer of FRP material is integrally formed. The size of the outermost layer of FRP is equivalent to the inner arc size of the shield tunnel segment 101 and is used to closely fit the inner arc surface of the shield tunnel segment 101;

[0068] S2.2: Determine the size and quantity of the multi-layer curved FRP profile 201. According to the size of the shield tunnel segment 101 to be strengthened and the strengthening requirements, calculate and design the specific size of the multi-layer curved FRP profile 201 and the quantity of the required multi-layer curved FRP profiles 201 to ensure the strengthening effect; Prepare the multi-layer curved FRP profile 201, and use the forming process of FRP materials, such as prepreg, pultrusion or winding, etc., to prepare the multi-layer curved FRP profile 201 that meets the design requirements;

[0069] S2.3: Select a structural adhesive material that meets the requirements to ensure its good stability and strength; Carry out surface treatment as needed: roughen the part to be repaired or bonded, and then clean it with a cleaning agent. Prepare the adhesive according to a certain ratio and use it up within the specified operation time limit;

[0070] S2.4: Paste several layers of FRP profiles together with staggered joints to form the multi-layer curved FRP profile 201. Coat the outer arc surface of the prepared multi-layer curved FRP profile 201 with structural adhesive not less than 5 mm thick, and then fit the outer arc surface of the multi-layer curved FRP profile 201 on the inner arc surface of the shield tunnel segment 101 to ensure that there are no bubbles and cavities. Use appropriate tools such as clamps and support frames to temporarily fix the multi-layer curved FRP profile 201 to prevent displacement before the structural adhesive solidifies;

[0071] S2.5: The structural adhesive solidifies to fix the multi-layer curved FRP profiles 201 on the inner wall of the tunnel segment 101;

[0072] S2.6: Through simulation experiments or actual use, verify the effectiveness of the multi-layer curved FRP profiles 201 in strengthening the shield tunnel structure, including indicators such as strengthening strength, durability, and impermeability;

[0073] The specific steps also include:

[0074] S2.61: Use computer simulation software to conduct stress analysis on the strengthened structure and optimize the design according to the results; in the stress analysis and optimization steps, introduce multi-physics field coupling analysis to more comprehensively evaluate the stress conditions of the structure;

[0075] The bearing capacity of the tunnel segment 101 strengthened with the multi-layer curved FRP profiles 201 should be checked according to the following formula:

[0076]

[0077] In the formula: σ represents the normal stress, which is the stress component perpendicular to the cross-section. According to the different directions of the load, the normal stress is further divided into tensile stress and compressive stress; tensile stress is positive and compressive stress is negative; τ represents the shear stress, which is the stress component parallel to the cross-section. Shear stress usually appears in shear deformation or torsional deformation, σ x 、σ y 、σ z are the normal stresses in the x, y, and z directions respectively, and τ xy 、τ yz 、τ zx are the shear stresses on the corresponding planes respectively. The stress distribution and deformation of the structure under different loads can be calculated, providing a basis for structural design and optimization;

[0078] Step S3: The structural adhesive solidifies to fix the multi-layer curved FRP profiles 201 on the inner wall of the tunnel segment 101, including:

[0079] S3.1: After gluing, the residues on the pipe wall should be cleaned in time to prevent the residues from affecting the subsequent construction;

[0080] S3.2: After gluing, the gluing effect should be detected, including the strength, density of the glue, and the bonding strength with the tunnel segment 101, etc.

[0081] The structure applying the design method of strengthening the shield tunnel structure with the above-mentioned multi-layer composite board includes a tunnel segment 101, anchor bolts 102, manholes 103, and multi-layer curved FRP profiles 201;

[0082] The tunnel segment 101 is fixed on the inner wall of the shield tunnel. A manhole 103 is provided on the outer wall of the tunnel segment 101, and anchor bolts 102 connected by bolts are provided on the inner wall of the tunnel segment 101;

[0083] Six tunnel segments 101 are spliced into a segment ring, and the segment ring is closely attached to the inside of the tunnel. The anchor bolts 102 on the outer walls on both sides of the tunnel segment 101 are connected by bolts to connect adjacent tunnel segments 101, and then they are connected and fixed by the bolts inside the manhole 103;

[0084] Multiple layers of curved FRP profiles 201 are provided on the inner wall of the tunnel segment 101, and the multiple layers of curved FRP profiles 201 are pasted with structural adhesive in a staggered joint structure by multiple single-layer FRP profiles;

[0085] The multiple layers of curved FRP profiles 201 are closely attached to the inner wall of the tunnel segment 101. The flanges on both sides are coated with structural adhesive and fixed on the inner wall of the tunnel segment 101, and the multiple layers of curved FRP profiles 201 are pasted in a staggered joint on the inner wall of the tunnel segment 101;

[0086] When applying the segment structural adhesive, surface treatment of the segment is carried out as required: roughen the part to be repaired or bonded, and then clean it with a cleaning agent. Prepare the adhesive according to a certain ratio and use it up within the specified operation time limit; during the process of applying the structural adhesive, control the application force and apply the structural adhesive evenly to avoid uneven adhesion with the tunnel segment 101 resulting in instability. After pasting, promptly clean the residues on the pipe wall to prevent the residues from affecting the subsequent construction;

[0087] After the gluing is completed, detect the gluing effect, including the strength, density of the glue, and the bonding strength with the tunnel segment 101, etc., and then form an integral body with the multiple layers of curved FRP profiles 201 and the tunnel segment 101 to enhance the structural strength of the tunnel segment 101.

[0088] A roadbed 302 is further provided on the inner wall of the tunnel segment 101, and a bracket 301 is provided on the outer wall of the roadbed 302. The roadbed 302 has functions such as conducting loads, preventing the transverse and longitudinal movement of the track, and draining water. The bracket 301 supports and fixes the roadbed 302 and can absorb a certain degree of impact force.

[0089] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A design method for strengthening a shield tunnel structure with a multi-layer composite board, characterized in that: It includes the following steps: Step S1: Plug the manhole (103), then mark the installation area in the area to be reinforced in the shield tunnel, clean and treat the surface of the tunnel segment (101) to ensure no sundries or oil stains, so as to ensure the tight bonding between the multi-layer curved FRP profiles (201) and the tunnel segment (101); Step S2: Install multi-layer curved FRP profiles (201) on the inner wall of the tunnel segment (101). The outer arc surface of the multi-layer curved FRP profiles (201) is covered with structural adhesive not less than 5 mm, and it is installed closely against the tunnel segment (101). The adjacent multi-layer curved FRP profiles (201) are aligned at the joints and glued, and the multi-layer curved FRP profiles (201) are pasted with staggered joints through the structural adhesive; Step S3: The structural adhesive solidifies, and the multi-layer curved FRP profiles (201) are fixed on the inner wall of the tunnel segment (101).

2. The design method of a multi-layer composite plate reinforced shield tunnel structure according to claim 1, characterized in that, The specific steps of the said Step S1 include: S1.1: Prepare suitable plugging materials, including fireproof sealant, steel plates, and bolts, to ensure that the materials meet the safety standards and design requirements; S1.2: For small manholes (103), directly fill them with sealant; for large manholes (103) or those that need to withstand greater pressure, steel plates need to be used for reinforcement and bolts need to be used for fastening for plugging; S1.3: After plugging, the sealing performance of the plugged area should be checked to ensure no air leakage or water leakage, so as to ensure the independence of the construction environment; S1.4: Use measuring tools, including total station and rangefinder, to accurately measure the specific position and size of the area to be reinforced; S1.5: According to the measurement results, use obvious markers, including paint and tape, on the tunnel segment (101) to mark the boundary line of the installation area; the markings should be clear, accurate, and easy to identify; S1.6: Use tools such as brooms and vacuum cleaners to remove sundries such as dust and sand on the surface of the tunnel segment (101). For stubborn oil stains and rust, use chemical cleaning agents or high-pressure water guns for in-depth cleaning; S1.7: After cleaning, treat the surface of the tunnel segment (101) to improve its bonding force with the multi-layer curved FRP profiles (201).

3. The design method of a multi-layer composite plate reinforced shield tunnel structure according to claim 2, characterized in that, The specific steps of the said Step S2 include: S2.1: Design the structure of the multi-layer curved FRP profiles (201). This structure is formed by staggering and pasting multi-layers of FRP materials. Each layer of FRP material is integrally formed. The size of the outermost layer of FRP is equivalent to the inner arc size of the shield tunnel segment (101) and is used to closely fit the inner arc surface of the shield tunnel segment (101); S2.2: Determine the size and quantity of the multi-layer curved FRP profiles (201). According to the size of the shield tunnel segment (101) to be reinforced and the reinforcement requirements, calculate and design the specific size of the multi-layer curved FRP profiles (201) and the quantity of the required multi-layer curved FRP profiles (201) to ensure the reinforcement effect; Prepare the multi-layer curved FRP profiles (201) using the forming process of FRP materials, including prepreg, pultrusion, or winding; S2.3: Select structural adhesive materials to ensure good stability and strength; conduct surface treatment: roughen the parts to be repaired or bonded, and then clean them with a cleaning agent; S2.4: Stagger the joints of several layers of FRP profiles and paste them together to form a multi-layer curved FRP profile (201). Coat the outer arc surface of the prepared multi-layer curved FRP profile (201) with structural adhesive with a thickness of not less than 5 mm. Then, attach the outer arc surface of the multi-layer curved FRP profile (201) to the inner arc surface of the shield tunnel segment (101), ensuring no air bubbles or cavities. Use appropriate tools, including clamps and support frames, to temporarily fix the multi-layer curved FRP profile (201) to prevent displacement before the structural adhesive solidifies; S2.5: The structural adhesive solidifies, and the multi-layer curved FRP profile (201) is fixed to the inner wall of the tunnel segment; S2.6: Through simulation experiments or actual use, verify the effect of the multi-layer curved FRP profile (201) in strengthening the shield tunnel structure, including indicators such as strengthening strength, durability, and impermeability.

4. The design method of a multi-layer composite plate reinforced shield tunnel structure according to claim 3, wherein The specific steps of S2.6 also include: Use computer simulation software to conduct stress analysis on the strengthened structure and optimize the design according to the results; in the stress analysis and optimization steps, introduce multi-physical field coupling analysis to more comprehensively evaluate the stress condition of the structure; The bearing capacity of the tunnel segment (101) strengthened with the multi-layer curved FRP profile (201) should be checked according to the following formula: In the formula: σ represents the normal stress, which is the stress component perpendicular to the cross-section. According to the different directions of the load, the normal stress is further divided into tensile stress and compressive stress; tensile stress is positive and compressive stress is negative; τ represents the shear stress, which is the stress component parallel to the cross-section. Shear stress usually appears in shear deformation or torsional deformation, σ x , σ y , σ z are the normal stresses in the x, y, and z directions respectively, and τ xy , τ yz , τ zx are the shear stresses on the corresponding planes respectively. Calculate the stress distribution and deformation of the structure under different loads, so as to provide a basis for structural design and optimization.

5. The design method of a multi-layer composite plate reinforced shield tunnel structure according to claim 4, characterized in that, The steps of S3 also include: S3.1: After gluing, the residues on the pipe wall should be cleaned in time to prevent the residues from affecting the subsequent construction; S3.2: After gluing, the gluing effect should be detected, including the strength, density of the glue, and the bonding strength with the tunnel segment (101).

6. The design method of a multi-layer composite plate reinforced shield tunnel structure according to claim 5, characterized in that For adjacent blocks and adjacent segments without cracks, use curved FRP profiles with a thickness of 6 - 10 mm. For the top with multiple transverse cracks that have occurred, use curved FRP profiles with a thickness of 10 - 15 mm for staggered multi-layer pasting.

7. The design method of a multi-layer composite plate reinforced shield tunnel structure according to claim 6, characterized in that, The surface of the multi-layer curved FRP profile (201) is coated with an anti-corrosion layer.

8. A structure applying the design method of a shield tunnel structure reinforced by a multi-layer composite board according to claim 1, 2, 3, 4, 5, 6 or 7, characterized in that, It includes a tunnel segment (101), anchor bolts (102), manholes (103), and multi-layer curved FRP profiles (201); The tunnel segment (101) is fixed to the inner wall of the shield tunnel. Manholes (103) are provided on the outer wall of the tunnel segment (101), and anchor bolts (102) connected by bolts are provided on the inner wall of the tunnel segment (101); Six tunnel segments (101) are spliced into a segment ring, and the segment ring is tightly attached to the inside of the tunnel. The anchor bolts (102) on the outer walls on both sides of the tunnel segment (101) are connected by bolts to connect adjacent tunnel segments (101), and are connected and fixed by bolts inside the manholes (103); The inner wall of the tunnel segment (101) is provided with multi-layer curved FRP profiles (201), and the multi-layer curved FRP profiles (201) are formed by staggering the joints of multiple single-layer FRP profiles and pasting them with structural adhesive; The multi-layer curved FRP profile (201) is closely attached to the inner wall of the tunnel segment (101), and the flanges on both sides are coated with structural adhesive and fixed to the inner wall of the tunnel segment (101). The multi-layer curved FRP profiles (201) are pasted with staggered joints on the inner wall of the tunnel segment (101).

9. The structure of a shield tunnel structure reinforced by a multi-layer composite board as claimed in claim 8, wherein A roadbed (302) is further arranged on the inner wall of the tunnel segment (101), and a bracket (301) is arranged on the outer wall of the roadbed (302).

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