Reinforcing structure and design method for corrosion tunnel lining

Abstract

This invention discloses a reinforcement structure and design method for corroded tunnel linings. The reinforcement structure is installed at the location of the lining to be reinforced. The reinforcement structure includes reinforcement members, a concrete layer connected to the reinforcement members, and connectors. The connectors are used to fix the reinforcement members to the concrete layer or to the tunnel lining. The reinforcement structure of this invention is applicable to conditions where the lining concrete has lost its structural strength and where it is impossible to attach fiber materials or anchor steel plates to the surface of the lining that has lost strength, thus adapting to the reinforcement of tunnels under large-area corrosion. In the design method of this invention, when selecting the next size of the reinforcement member, determining whether to select reinforcement members in ascending or descending order of size can greatly reduce the amount of calculation required to select a suitable size. Furthermore, it allows for the selection of either a larger size reinforcement member upwards or a smaller, more economical size reinforcement member downwards, based on whether the requirements are met.

Description

Technical Field

[0001] This invention relates to the field of tunnel structures, and more specifically to a reinforcement structure and design method for corroded tunnel linings. Background Technology

[0002] Due to poor early construction quality, long-term environmental erosion, and the effects of train dynamic loads, aging tunnels commonly suffer from problems such as water leakage, lining cracking, and concrete corrosion, severely impacting the normal operation of railway lines. This is particularly true in western my country, where the corrosive environment of sulfates exacerbates the widespread corrosion of tunnel lining concrete. Therefore, how to reinforce and repair these corroded and deteriorated operational tunnels has become a major challenge and urgent need in my country's tunnel engineering field.

[0003] The existing technology has the following problems: For plain concrete lining structures with large-area corrosion and deterioration, since the lining concrete has lost its structural strength within a certain thickness range, it is impossible to attach fiber materials or anchor steel plates to the surface of the lining that has lost its strength during actual repair. Often, it is necessary to remove the severely corroded parts before the next step of reinforcement construction can be carried out. At the same time, there is no quantitative calculation method for the mechanical transformation mechanism and design of the lining structure after reinforcement and repair. In actual construction, the repair design scheme is mostly determined by experience judgment, and the reliability and economy of the design lack rigorous theoretical basis.

[0004] In summary, there is an urgent need for a reinforcement structure and design method for corroded tunnel linings to address the problems of tunnel reinforcement in existing technologies and the lack of quantitative guidance. Summary of the Invention

[0005] The purpose of this invention is to provide a reinforcement structure and design method for corroded tunnel linings, in order to solve the problems of insufficient quantitative guidance in existing tunnel reinforcement technologies. The specific technical solution is as follows:

[0006] A reinforcement structure for corroded tunnel lining is provided, wherein the reinforcement structure is disposed at the location of the lining to be reinforced in the tunnel; the reinforcement structure includes a reinforcement member, a concrete layer connected to the reinforcement member, and a connector, wherein the connector is used to fix the reinforcement member to the concrete layer or to the lining.

[0007] In the preferred embodiment of the above technical solution, the reinforcing member is an arc-shaped channel steel, the connecting member is an expansion bolt, the channel steel is set within the concrete layer, and the web of the channel steel is tightly attached to the position of the lining to be reinforced. The expansion bolt connects the lining and the web of the channel steel.

[0008] Alternatively, the reinforcing member may be an arc-shaped corrugated plate, the connecting member may be a rivet, the concrete layer may be tightly attached to the lining at the location to be reinforced, the corrugated plate may be placed on the side of the concrete layer away from the lining, and the corrugated plate may be fixed to the concrete layer by rivets.

[0009] In the preferred embodiment of the above technical solution, the concrete layer is a micro-expansion concrete layer.

[0010] A design method for a reinforcement structure of a corroded tunnel lining, used to achieve the reinforcement structure, the design method includes the following steps:

[0011] Step S1: Investigation and sampling. Mechanical tests are conducted on the corroded concrete lining samples to obtain relevant parameters.

[0012] Step S2: Based on relevant parameters, establish a load structure mode calculation model and calculate the internal force values ​​of each section of the lining;

[0013] Step S3: Based on the internal force values ​​of each section, determine the most unfavorable section of the original lining, and take the stress state of this section as the design ultimate bearing capacity N0 of the lining structure.

[0014] Step S4: Select appropriate reinforcement components for reinforcement, following the selection rules as follows:

[0015] Step S4.1: Randomly select an initial specification as the current specification;

[0016] Step S4.2: Calculate the crack resistance N of the lining structure after reinforcement with the current specification of the reinforcement members. cr and ultimate bearing capacity N cu ;

[0017] Step S4.3: Select the next specification of reinforcement component in ascending or descending order of specifications, and calculate N corresponding to the next specification. cr and N cu ;

[0018] Step S4.4: If the current specification and the next specification correspond to N cr and N cu If the requirements are met, select the appropriate reinforcement component; otherwise, use the next specification as the current specification and return to step S4.2.

[0019] The rules for determining whether the requirements are met are as follows:

[0020] When selecting reinforcement components in ascending order of specifications, if the minimum value of the current specification is satisfied... cr N cu}<N0, and the next specification corresponds to min{N cr N cu When}≥N0, the reinforcement component of the next specification shall be used as the final determined reinforcement component;

[0021] When selecting reinforcement components in descending order of specifications, if the minimum value of the current specification is satisfied... cr N cu}≥N0, and the next specification corresponds to min{N} cr N cu If} < N0, then the reinforcement component of the current specification will be used as the final determined reinforcement component.

[0022] In the preferred embodiment of the above technical solution, the relevant parameters in step S1 include the tunnel cross-sectional geometry, the corrosion depth of the lining concrete, the original design thickness of the lining, the original design concrete strength grade of the lining concrete, the tunnel surrounding rock grade, and the physical and mechanical parameters of the surrounding rock.

[0023] In the preferred embodiment of the above technical solution, in step S1, a core sample of the lining concrete is drilled in the corroded area using a core drilling machine, and the sampling rules are as follows:

[0024] When the corrosion area is ≤1m 2 One core sample was drilled from the corrosion center;

[0025] When 1m 2 Corrosion area ≤ 4m 2 Three core samples were drilled in the corrosion center area, with a drill hole spacing of 1m.

[0026] When the corrosion area > 4m 2 Five core samples were drilled in the corrosion center area, with a drill hole spacing of 1m.

[0027] In the preferred embodiment of the above technical solution, before proceeding to step S4, it is first determined whether to select channel steel or corrugated plate as the reinforcing component. The selection rules are as follows:

[0028] When the corrosion depth of the lining concrete is greater than or equal to 10cm, channel steel is selected as the reinforcement.

[0029] When the corrosion depth of the lining concrete is less than 10cm, corrugated plates are selected as the reinforcement components.

[0030] In the preferred embodiment of the above technical solution, when channel steel is selected as the reinforcing component, N in step S4.2 cr and N cu As shown in equations 1) and 2):

[0031] Crack resistance bearing capacity N cr ;

[0032]

[0033] Ultimate bearing capacity N cu ;

[0034]

[0035] Among them, E c The elastic modulus of uncorroded concrete; ε tux is the ultimate tensile strain at the edge of the concrete on the tension side; h is the cross-sectional thickness of the tunnel lining; x n b is the height of the compression zone at the time of cracking; f is the longitudinal width of the tunnel lining; t E represents the design value for the tensile strength of the newly poured concrete layer. s b is the elastic modulus of steel. c A is the length of the flange of the channel steel; sc1 A is the cross-sectional area of ​​the channel steel flange; sc2 denoted as , where is the cross-sectional area of ​​the channel steel web; e is the cross-sectional eccentricity.

[0036] f c ε represents the design compressive strength of non-corroded concrete. cu This represents the compressive strain at the edge of the concrete on the compression side.

[0037] In the preferred embodiment of the above technical solution, when a corrugated plate is selected as the reinforcing component, N in step S4.2 cr and N cu As shown in equations 3) and 4):

[0038] Crack resistance bearing capacity N cr ;

[0039]

[0040] Ultimate bearing capacity N cu ;

[0041]

[0042] Among them, E c The elastic modulus of uncorroded concrete; ε tu x is the ultimate tensile strain at the edge of the concrete on the tension side; h is the cross-sectional thickness of the tunnel lining; x n b is the height of the compression zone at the time of cracking; f is the longitudinal width of the tunnel lining; t E represents the design value for the tensile strength of the newly poured concrete layer. s A represents the elastic modulus of steel. sg denoted as , where is the cross-sectional area of ​​the corrugated plate; e is the eccentricity of the cross-section.

[0043] f c ε represents the design compressive strength of non-corroded concrete. cu This represents the compressive strain at the edge of the concrete on the compression side.

[0044] In the preferred embodiment of the above technical solution, in step S4.3, the determination of whether to select the next specification reinforcement component in ascending or descending order of specifications is based on the following rules:

[0045] The first step is to obtain N calculated for the current specification of the reinforcement component in step S4.2.cr and N cu ;

[0046] The second step is to determine the min{N} of the reinforcement component corresponding to the current specification, based on the first step. cr N cu The value of} is compared with N0.

[0047] If min{N cr N cu If} > N0, then the next specification of reinforcement component is selected in descending order of specification; otherwise, the next specification of reinforcement component is selected in ascending order of specification.

[0048] The application of the technical solution of the present invention has the following beneficial effects:

[0049] (1) In this invention, the reinforcement structure for the corroded tunnel lining is set at the location of the lining to be reinforced (the corroded part of the location to be reinforced has been removed in advance). The reinforcement structure includes a reinforcement member and a concrete layer and a connector connected to the reinforcement member. The connector is used to fix the reinforcement member on the concrete layer or to the tunnel lining. The reinforcement structure in this invention can be applied to the working conditions where the lining concrete has lost its structural strength and it is impossible to paste fiber materials or anchor steel plates on the lining surface that has lost its strength, so as to adapt to the reinforcement of the tunnel when there is large-area corrosion.

[0050] (2) In this invention, there are two forms of reinforcement structure. The more suitable reinforcement structure can be selected according to the actual corrosion situation. Specifically, in the channel steel type reinforcement structure: the channel steel is embedded in the concrete layer (micro-expansion concrete layer), which requires less space for the thickness of the reinforcement lining and avoids lining encroachment. It is suitable for working conditions where the corrosion depth of the lining is ≤10cm. In the corrugated plate type reinforcement structure: the corrugated plate has sufficient gap with the original lining after the corrosion layer is removed, which can ensure the grouting quality of the concrete layer (micro-expansion concrete layer). At the same time, compared with the channel steel type reinforcement structure, the corrugated plate type reinforcement structure has a stronger bearing capacity after reinforcement and is suitable for working conditions where the corrosion depth of the lining is >10cm.

[0051] (3) The concrete layer in this invention is used to fill the removed corroded concrete lining, and the concrete layer is a micro-expansion concrete layer, which ensures the compactness of the filling through its micro-expansion.

[0052] (4) The design method for the reinforcement structure of the corrosion tunnel lining of the present invention is used to realize the reinforcement structure. The design method includes steps S1 to S4. In step S4, the specifications of the reinforcement members most suitable for the current working conditions are selected by increasing or decreasing the specifications. This avoids economic waste caused by using excessively large specifications or structural strength failure caused by using excessively small specifications. That is, the method of the present invention quantifies the selection of key components (i.e., specification selection), which can provide reliable and effective guidance for the site. The crack resistance N of the lining structure after reinforcement is increased. cr and ultimate bearing capacity N cu The smaller of the two values ​​is compared with the design ultimate bearing capacity N0 to ensure that the selected reinforcement of the final specification can meet the structural strength requirements, thus combining economy and practicality.

[0053] (5) In step S1 of the present invention, core samples of the lining concrete are drilled in the corrosion area by a core drilling machine. When sampling, the number and location of sampling points are selected according to the corrosion area. This allows for a more comprehensive understanding of the overall corrosion of the tunnel lining structure while ensuring the safety of the existing tunnel lining structure, and provides a sample source for the subsequent numerical calculation parameter values.

[0054] (6) Before proceeding to step S4, the present invention first determines whether to select channel steel or corrugated plate as reinforcement, that is, to determine the form of reinforcement structure selected based on the corrosion depth, which can be effectively applied to the current working conditions.

[0055] (7) In the method of the present invention, Formula 1) and Formula 2) provide quantitative guidance for the selection of the specifications of the channel steel reinforcement structure, ensuring that the selected channel steel takes into account both structural strength and economy. Similarly, Formula 3) and Formula 4) provide quantitative guidance for the selection of corrugated plates.

[0056] (8) In the method of the present invention, when selecting the next specification of the reinforcement, the determination of whether the specification is increasing or decreasing can greatly reduce the amount of calculation required to select a suitable specification of reinforcement. Specifically, in step S4.1, a reinforcement of a specification close to the actual working condition (i.e., the initial current specification reinforcement) can be pre-selected based on experience. In this way, it is not necessary to calculate for each specification to determine a close value. Then, N is calculated based on the current specification reinforcement in step S4.1. cr and N cu And select N cr and N cu By comparing the smaller of the two values ​​with N0, it can be determined whether the strength requirements of the current reinforcement specification are met. Based on whether the requirements are met, it can be decided whether to select a larger reinforcement specification or a smaller, more economical reinforcement specification.

[0057] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0058] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0059] Figure 1 This is a schematic diagram of the reinforcement structure for the corroded tunnel lining in this embodiment (showing a channel steel reinforcement structure). Figure 1 (a) is a schematic diagram of the cross section, and (b) is a schematic diagram of the longitudinal section.

[0060] Figure 2 yes Figure 1 AA view in (a);

[0061] Figure 3 This is a schematic diagram of the reinforcement structure for the corroded tunnel lining in this embodiment (showing a corrugated plate type reinforcement structure). Figure 3 (a) is a schematic diagram of the cross section, and (b) is a schematic diagram of the longitudinal section.

[0062] Figure 4 yes Figure 3 BB view in (a);

[0063] Figure 5 This is a schematic diagram of sampling corroded concrete in this embodiment. Figure 5 In the diagram, (a) indicates a corrosion area of ​​less than 1m². 2 (b) indicates that the corrosion area is greater than 1m. 2 And less than or equal to 4m 2 (c) indicates that the corrosion area is greater than 4m². 2 M1 indicates the corroded area; M2 indicates the location for core drilling.

[0064] Figure 6 This is a simplified diagram for calculating the crack resistance bearing capacity of a channel steel reinforced structure. Figure 6 In the diagram, (a) represents the stress distribution diagram of the reinforced section, (b) represents the stress distribution diagram of the section, and (c) represents the strain distribution diagram of the section.

[0065] Figure 7 yes Figure 6 Schematic diagram of the cross-section of the channel steel in the diagram;

[0066] Figure 8 This is a simplified diagram for calculating the ultimate bearing capacity of a channel steel reinforced structure. Figure 8In the diagram, (a) represents the stress distribution diagram of the reinforced section, (b) represents the stress distribution diagram of the section, and (c) represents the strain distribution diagram of the section.

[0067] Figure 9 This is a simplified diagram for calculating the crack resistance and bearing capacity of a corrugated plate reinforced structure. Figure 9 In the diagram, (a) represents the stress distribution of the reinforced section, (b) represents the stress distribution of the section at the time of cracking, and (c) represents the strain distribution of the section at the time of cracking.

[0068] Figure 10 This is a simplified diagram for calculating the ultimate bearing capacity of a corrugated plate reinforced structure. Figure 10 In the diagram, (a) shows the stress distribution of the cross section after reinforcement, (b) shows the stress distribution of the cross section during crushing failure, and (c) shows the strain distribution of the cross section during crushing failure.

[0069] Among them, 1. Reinforcement structure; 1.1 Reinforcement components; 1.1a. Channel steel; 1.1b. Corrugated plate; 1.2. Concrete layer; 1.3. Connectors; 1.3a. Expansion bolts; 1.3b. Rivets; 2. Lining;

[0070] Figures 6 to 10 The meanings of each character in the text are as follows:

[0071] b is the longitudinal width of the tunnel lining; x n f is the height of the compression zone of the cross-section at the time of cracking. t is the design value of the tensile strength of the newly poured concrete layer; e is the cross-sectional eccentricity; h is the cross-sectional thickness of the tunnel lining; N cr For crack resistance and bearing capacity; f sc1 A represents the tensile strain at the geometric center of the channel steel flange; sc1 f is the cross-sectional area of ​​the channel steel flange; sc2 A represents the tensile strain of the web of the channel steel. sc2 σ is the cross-sectional area of ​​the web of the channel steel; cr b is the compressive stress in the concrete layer at the edge of the compression side; c ε is the length of the flange of the channel steel; tu ε represents the ultimate tensile strain at the edge of the concrete on the tension side. sc1 ε is the tensile strain at the geometric center of the channel steel flange; sc2 ε is the tensile strain of the web of the channel steel; cr d represents the compressive strain at the edge of the concrete on the compression side. c b is the thickness of the web of the channel steel; c t is the length of the channel steel flange; c h is the thickness of the channel steel flange. c ε is the height of the channel steel; cu f is the compressive strain at the edge of the concrete on the compression side. cThe design value for the compressive strength of non-corroded concrete; N cu σ represents the ultimate bearing capacity of the cross section. sg The tensile stress of the corrugated plate; A sg This represents the cross-sectional area of ​​the corrugated plate. Detailed Implementation

[0072] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered by the claims.

[0073] Example:

[0074] This embodiment discloses a reinforcement structure and design method for corroded tunnel linings. First, the reinforcement structure for the corroded tunnel lining in this embodiment is described, such as... Figures 1 to 4 As shown, the details are as follows:

[0075] like Figure 1 and Figure 3 As shown, in this embodiment, the reinforcement structure 1 is located at the reinforcement site of the lining 2, which is the location in the lining where corrosion has occurred. The corroded portion of the lining at the reinforcement site needs to be removed before the reinforcement structure 1 can be used for further reinforcement. The reinforcement structure 1 specifically includes a reinforcement member 1.1, a concrete layer 1.2 connected to the reinforcement member, and a connector 1.3. The connector 1.3 is used to fix the reinforcement member 1.1 to the lining 2 where the corrosion has been removed, or to fix the reinforcement member 1.1 to the outside of the concrete layer 1.2 (i.e., the side away from the lining). The concrete layer 1.2 of the reinforcement structure 1 is used to fill the pre-removed corroded concrete lining. The reinforcement structure 1 in this embodiment has two forms: a channel steel reinforcement structure and a corrugated plate reinforcement structure, as detailed below:

[0076] Channel steel reinforcement structure, such as Figure 1 and Figure 2 As shown below:

[0077] The reinforcing component 1.1 in the reinforcing structure 1 is a channel steel 1.1a. The channel steel 1.1a is arc-shaped, and the curvature of the arc matches the curvature of the tunnel lining, so that the outer side of the web of the channel steel 1.1a is in close contact with the position to be reinforced (the corroded parts have been removed in advance). Preferably, multiple sets of channel steels 1.1a in the reinforcing structure 1 are arranged along the inner arc of the tunnel, forming a full ring arrangement. In the axial direction of the tunnel, multiple sets of channel steels 1.1a are arranged with a spacing of 1m between them in the area to be reinforced.

[0078] The connector 1.3 in the reinforcement structure 1 is an expansion bolt 1.3a. The channel steel 1.1a is fixed and tightly attached to the lining 2 by the expansion bolt 1.3a. Multiple sets of expansion bolts 1.3a are evenly arranged circumferentially along each ring of channel steel 1.1a with a spacing of 0.5m. The anchoring end of the expansion bolt 1.3a is embedded in the uncorroded concrete lining to a depth of 10cm.

[0079] The channel steel 1.1a is set (e.g., embedded or fixed in) within the concrete layer 1.2, and the lining is filled through the concrete layer 1.2 to fill the area that has been chiseled away and corroded.

[0080] Corrugated plate reinforced structure, such as Figure 3 and Figure 4 As shown below:

[0081] The reinforcing component 1.1 in the reinforcement structure 1 is a corrugated plate 1.1b (i.e., corrugated steel plate). The shape of the corrugated plate 1.1b is arc-shaped, and the curvature of the arc is consistent with that of the original lining. In this way, after the concrete layer 1.2 fills the removed corroded area (i.e., the concrete layer 1.2 is poured on the removed corroded area), the corrugated plate 1.1b can fit against the outside of the concrete layer 1.2 (the side away from the lining). Among them, multiple sets of corrugated plates 1.1b in the reinforcement structure 1 are arranged along the inner arc of the tunnel on the outside of the concrete layer 1.2, forming a full ring arrangement (i.e., the corrugated steel plate is arranged along the entire ring of the lining). The connecting component 1.3 in the reinforcement structure 1 is a rivet 1.3b. The rivet 1.3b is used to fix the corrugated plate 1.1b to the outside of the concrete layer 1.2. Multiple sets of rivets 1.3b are arranged at 1m intervals along the circumferential and longitudinal directions of the tunnel. The rivet 1.3b is embedded 10cm into the concrete layer 1.2.

[0082] In the aforementioned channel steel reinforcement structure and corrugated plate 1.1b reinforcement structure 1, the concrete layer 1.2 is a micro-expansion concrete layer, specifically:

[0083] The micro-expansion concrete layer 1.2 includes cement, coarse aggregate, fine aggregate, water, water-reducing agent, and expansion agent. The mix proportion (by mass) of the micro-expansion concrete is cement:coarse aggregate:fine aggregate:water:water-reducing agent:expansion agent = 484.32:753.11:862.69:208.26:1.94:2.85. Furthermore, the cement is ordinary Portland cement; the coarse aggregate has an apparent density of 2720 kg / m³. 3 The crushed stone has a particle size of 5-10mm; the fine aggregate is natural yellow sand with a fineness modulus of 2.7; the admixtures are polycarboxylate high-efficiency air-entraining water-reducing agent and calcium sulfoaluminate expansion agent; and the water is tap water.

[0084] This embodiment also discloses a design method for a reinforcement structure of a corroded tunnel lining, used to implement the reinforcement structure (mainly enabling the selection of reinforcement components). The design method includes steps S1 to S4, such as... Figures 5 to 10 As shown, the details are as follows:

[0085] Step S1: Investigation and sampling. Mechanical tests are conducted on the corroded lining concrete samples to obtain relevant parameters. These parameters include the tunnel cross-sectional geometry, corrosion depth of the lining concrete, original design thickness of the lining, original design strength grade of the lining concrete, tunnel surrounding rock grade, and physical and mechanical parameters of the surrounding rock. The specific sub-steps are as follows:

[0086] Step S1.1: Investigation and sampling are conducted to understand the original design parameters, corrosion degree, and distribution pattern of the tunnel lining structure, and to collect samples of corroded concrete.

[0087] Step S1.2: Through on-site investigation, measure the corrosion status of the tunnel lining, including the corrosion range and distribution location. The corrosion range includes the width and length of the corrosion area; the distribution location includes three parts: the arch crown, the arch waist, and the sidewalls. This is used to comprehensively understand the distribution characteristics of tunnel lining defects and provide a direct basis for the establishment of subsequent numerical models.

[0088] Step S1.3: As Figure 5 As shown, core samples of the lining concrete were drilled in the corroded area using a core drilling machine.

[0089] When the corrosion area is ≤1m 2 One core sample was drilled from the corrosion center;

[0090] When 1m 2 Corrosion area ≤ 4m 2 Three core samples were drilled in the corrosion center area, with a drill hole spacing of 1m.

[0091] When the corrosion area > 4m 2 Five core samples were drilled in the corrosion center area, with a drill hole spacing of 1m.

[0092] This step S1.3 is used to gain a more comprehensive understanding of the overall corrosion of the tunnel lining structure while ensuring the safety of the existing tunnel lining structure, and to provide a sample source for the subsequent numerical calculation parameter values.

[0093] Step S1.4: Based on the drilled core samples, the corrosion depth of the lining concrete is determined by phenolphthalein titration.

[0094] Step S1.5: Conduct mechanical tests on the corroded lining concrete samples, i.e., conduct indoor mechanical tests. The indoor mechanical tests include: using uniaxial compressive strength test and splitting fracture test to determine the uniaxial compressive strength, elastic modulus and tensile strength values ​​of the corroded concrete material, respectively.

[0095] Step S2: Based on relevant parameters, establish a load-structure model calculation model and calculate the internal force values ​​of each section of the lining. Specifically, according to the original tunnel lining structure design parameters, establish a load-structure model calculation model and calculate the internal force values ​​of each section of the lining, namely bending moment M and axial force N.

[0096] Step S3: Based on the internal force values ​​of each section, determine the most unfavorable section of the original lining, and use the stress state of this section as the design ultimate bearing capacity N of the lining structure. O Specifically, the most unfavorable section of the original lining is determined by the failure stage method, and the stress state of this section is taken as the design ultimate bearing capacity N0 of the lining structure, that is, the bearing capacity and the section eccentricity e.

[0097] Preferably, before proceeding to step S4, it is first necessary to determine whether to select channel steel or corrugated plate (i.e., corrugated steel plate) as the reinforcement. In other words, it is necessary to determine whether to use a channel steel reinforcement structure or a corrugated plate reinforcement structure based on the working conditions. The specific determination rule is as follows:

[0098] When the corrosion depth of the lining concrete is greater than or equal to 10cm, channel steel is selected as the reinforcement component, that is, a channel steel reinforcement structure is adopted.

[0099] When the corrosion depth of the lining concrete is less than 10cm, corrugated plates are selected as the reinforcement components, that is, a corrugated plate type reinforcement structure is adopted.

[0100] Step S4: Select appropriate reinforcement components for reinforcement. Step S4 includes three sub-steps, S4.1 to S4.4, with the following selection rules:

[0101] Step S4.1: Based on the on-site working conditions and experience, within the scope of national standards, arbitrarily select a reinforcement component of a specification that meets or is close to meeting the requirements (i.e., select the initial specification reinforcement component), and use this initial specification reinforcement component as the current specification reinforcement component; it should be noted here that the initial specification reinforcement component selection can be based on experience and working conditions. Even if the selected initial specification does not meet the requirements, it will not affect the implementation of this solution. The initial specification selection is to prepare for the reinforcement component that is close to the final selected specification, which can reduce the corresponding amount of calculation.

[0102] Step S4.2: Calculate the crack resistance N of the lining structure after reinforcement with the current specifications in step S4.1. cr and ultimate bearing capacity N cu ;

[0103] This refers to N cr and N cuIt should be noted that, before proceeding to step S4, it is necessary to determine whether to select channel steel or corrugated plate as the reinforcing member. Therefore, for N... cr and N cu The calculations are divided into two cases: when channel steel is selected as the reinforcing member and when corrugated plate is selected as the reinforcing member. The details are as follows:

[0104] When selecting channel steel as a reinforcing component, such as Figures 6 to 8 N cr and N cu Specifically, as shown in equations 1) and 2):

[0105] Crack resistance bearing capacity N cr ,like Figures 6 to 7 As shown;

[0106]

[0107] Ultimate bearing capacity N cu ,like Figure 8 As shown;

[0108]

[0109] Among them, E c The elastic modulus of uncorroded concrete; ε tu ε represents the ultimate tensile strain at the edge of the concrete on the tension side. tu Take 300με; h is the cross-sectional thickness of the tunnel lining; x n b is the height of the compression zone at the time of cracking; f is the longitudinal width of the tunnel lining; t E represents the design value for the tensile strength of the newly poured concrete layer. s b is the elastic modulus of steel. c A is the length of the flange of the channel steel; sc1 A is the cross-sectional area of ​​the channel steel flange; sc2 is the cross-sectional area of ​​the channel steel web; e is the cross-sectional eccentricity; f c ε represents the design compressive strength of non-corroded concrete. cu For the compressive strain at the edge of the concrete on the compression side, ε is taken in this embodiment. cu =250με.

[0110] When selecting corrugated plates as reinforcement components, such as Figures 9 to 10 N cr and N cu Specifically, as shown in equations 3) and 4):

[0111] Crack resistance bearing capacity N cr ,like Figure 9 As shown;

[0112]

[0113] Ultimate bearing capacity N cu ,like Figure 10 As shown;

[0114]

[0115] Among them, E c The elastic modulus of uncorroded concrete; ε tu ε represents the ultimate tensile strain at the edge of the concrete on the tension side. sg The tensile strain of the corrugated steel plate is related to ε. tu Equal; σ sg The tensile stress of the corrugated plate is denoted by h; the cross-sectional thickness of the tunnel lining is denoted by x. n b is the height of the compression zone at the time of cracking; f is the longitudinal width of the tunnel lining; t E represents the design value for the tensile strength of the newly poured concrete layer. s A represents the elastic modulus of steel. sg is the cross-sectional area of ​​the corrugated plate; e is the eccentricity of the cross-section; f c ε represents the design compressive strength of non-corroded concrete. cu This represents the compressive strain at the edge of the concrete on the compression side.

[0116] Step S4.3: Select the next specification of reinforcement component in ascending or descending order of specifications, and calculate N corresponding to the next specification according to step S4.2. cr and N cu In step S4.3, whether the next specification is selected in ascending or descending order is determined according to the following rules:

[0117] The first step is to calculate N based on the current specification of the reinforcement obtained in step S4.2. cr and N cu The following judgment is made;

[0118] The second step is to determine the min{N} of the reinforcement component corresponding to the current specification, based on the first step. cr N cu The value of} is compared with N0, here for min{N cr N cu The expression means that N is selected. cr and N cu The smaller of the two values ​​is taken as the output value of the expression;

[0119] Where, if min{N cr N cuIf} > N0, then the next specification of the reinforcement component is selected in descending order of specification, that is, a reinforcement component with a smaller specification than the current specification is selected; conversely, if} > N0, then the next specification of the reinforcement component is selected in ascending order of specification, that is, a reinforcement component with a larger specification than the current specification is selected. It should be noted that the reinforcement components (i.e., channel steel and corrugated plate) in this embodiment all have corresponding national standards. Therefore, when selecting, the model and specification can be selected in ascending or descending order according to the national standards.

[0120] Step S4.4: If the current specification and the next specification correspond to N cr and N cu If the requirements are met, select the appropriate reinforcement component; otherwise, use the next specification as the current specification and return to step S4.2. Step S4.4 means that if N occurs... cr and N cu When the requirements are met, the corresponding specification of the reinforcement (i.e., channel steel or corrugated steel plate) is selected as the final solution. If the requirements are not met, the next specification of reinforcement is used as the current specification of reinforcement in step S4.2, and subsequent calculations are performed. This process is repeated until the requirements are met in step S4.4.

[0121] In step S4.4, N cr and N cu The rules for determining whether the requirements are met are as follows:

[0122] First, it should be noted that in step S4.3 above, it is necessary to confirm whether the selected specification direction is increasing or decreasing (see above for details), therefore, it is divided into the following two cases:

[0123] When selecting reinforcement components in ascending order of specifications, if the minimum value of the current specification is satisfied... cr N cu}<N0, and the next specification corresponds to min{N cr N cu When}≥N0, the reinforcement component of the next specification shall be used as the final determined reinforcement component;

[0124] When selecting reinforcement components in descending order of specifications, if the minimum value of the current specification is satisfied... cr N cu}≥N0, and the next specification corresponds to min{N} cr N cu If} < N0, then the reinforcement component of the current specification will be used as the final determined reinforcement component.

[0125] Once the appropriate reinforcement components are obtained (i.e., the finalized reinforcement components), they can be used to reinforce the tunnel lining. Specifically:

[0126] When using a channel steel structure, the channel steel of this specification is arranged in a full ring around the area to be reinforced in the tunnel and fixed to the lining with expansion bolts. Then, a concrete layer is poured (the concrete layer is flush with the inner side of the original lining, that is, the side of the concrete layer closest to the inner side of the tunnel axis and the side of the original lining closest to the inner side of the tunnel axis are located on the same inner arc surface).

[0127] When using a corrugated plate structure, firstly, a concrete layer is poured at the location of the lining to be reinforced (where the corroded parts have been removed beforehand). The selected corrugated plates are then fixed to the side of the concrete layer near the tunnel axis with rivets, and multiple sets of corrugated plates are arranged in a full ring. Preferably, the thickness of the concrete layer plus the thickness of the corrugated plates should not protrude radially beyond the original lining of the tunnel (i.e., the corrugated plates should not extend inward beyond the original lining).

[0128] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A design method for a reinforcement structure of a corroded tunnel lining, used to achieve a reinforcement structure (1), characterized in that, The design methodology includes the following steps: Step S1: Investigation and sampling. Mechanical tests are conducted on the corroded concrete lining samples to obtain relevant parameters. Step S2: Based on relevant parameters, establish a load structure mode calculation model and calculate the internal force values ​​of each section of the lining; Step S3: Based on the internal force values ​​of each section, determine the most unfavorable section of the original lining, and use the stress state of this section as the design ultimate bearing capacity of the lining structure. ; Step S4: Select appropriate reinforcement components for reinforcement, following the selection rules as follows: Step S4.1: Randomly select an initial specification as the current specification; Step S4.2: Calculate the crack resistance of the lining structure after reinforcement with the current specification of the reinforcement members. and ultimate bearing capacity ; Step S4.3: Select the next specification of reinforcement component in ascending or descending order of specifications, and calculate the corresponding value of the next specification. and ; Step S4.4: If the current specification and the next specification correspond to... and If the requirements are met, select the appropriate reinforcement component; otherwise, use the next specification as the current specification and return to step S4.

2. The rules for determining whether the requirements are met are as follows: When selecting reinforcement components in ascending order of specifications, if the current specification is satisfied... And the next specification corresponds to If so, the reinforcement component of the next specification shall be used as the final reinforcement component; When selecting reinforcement components in descending order of specifications, if the current specification is met... And the next specification corresponds to In this case, the reinforcement component of the current specification shall be used as the final reinforcement component; In step S1, the relevant parameters include the tunnel cross-sectional geometry, the corrosion depth of the lining concrete, the original design thickness of the lining, the original design strength grade of the lining concrete, the tunnel surrounding rock grade, and the physical and mechanical parameters of the surrounding rock. When channel steel is selected as the reinforcing component, in step S4.2 and As shown in equations 1) and 2): Crack resistance bearing capacity ; 1）； Ultimate bearing capacity ; 2）； in, The elastic modulus of uncorroded concrete; This represents the ultimate tensile strain at the edge of the concrete on the tension side. The cross-sectional thickness of the tunnel lining; This represents the height of the compression zone in the cross-section when cracking occurs. The longitudinal width of the tunnel lining; The design value for the tensile strength of the newly poured concrete layer; The elastic modulus of steel; The length of the flange of the channel steel; This represents the cross-sectional area of ​​the channel steel flange. This represents the cross-sectional area of ​​the web of the channel steel. The cross-sectional eccentricity; This represents the design value for the compressive strength of non-corroded concrete. This refers to the compressive strain at the edge of the concrete on the compression side; When a corrugated plate is selected as the reinforcement component, in step S4.2 and As shown in equations 3) and 4): Crack resistance bearing capacity ; 3）； Ultimate bearing capacity ; 4）； in, The elastic modulus of uncorroded concrete; This represents the ultimate tensile strain at the edge of the concrete on the tension side. The cross-sectional thickness of the tunnel lining; This represents the height of the compression zone in the cross-section when cracking occurs. The longitudinal width of the tunnel lining; The design value for the tensile strength of the newly poured concrete layer; The elastic modulus of steel; This represents the cross-sectional area of ​​the corrugated plate. The cross-sectional eccentricity; This represents the design value for the compressive strength of non-corroded concrete. This refers to the compressive strain at the edge of the concrete on the compression side; In step S4.3, the determination of whether to select the next specification reinforcement component in ascending or descending order of specifications is based on the following rules: The first step is to obtain the reinforcement components calculated in step S4.2 for the current specifications. and ; The second step is to determine the corresponding reinforcement component of the current specification from the first step. The value and Comparison, like If the specifications are in descending order, then the next specification of reinforcement component is selected; otherwise, the next specification of reinforcement component is selected in ascending order. The reinforcement structure (1) is set at the location of the lining (2) in the tunnel to be reinforced; the reinforcement structure (1) includes a reinforcement member (1.1) and a concrete layer (1.2) and a connector (1.3) connected to the reinforcement member (1.1). The connector (1.3) is used to fix the reinforcement member (1.1) to the concrete layer (1.2) or to the lining (2); The reinforcing member (1.1) is an arc-shaped channel steel (1.1a), and the connecting member (1.3) is an expansion bolt (1.3a). The channel steel (1.1a) is placed inside the concrete layer (1.2), and the web of the channel steel (1.1a) is tightly attached to the position of the lining to be reinforced. The expansion bolt (1.3a) connects the lining and the web of the channel steel (1.1a). Alternatively, the reinforcing member (1.1) may be an arc-shaped corrugated plate (1.1b), the connector (1.3) may be a rivet (1.3b), the concrete layer (1.2) may be tightly attached to the lining to be reinforced, the corrugated plate (1.1b) may be located on the side of the concrete layer (1.2) away from the lining, and the corrugated plate (1.1b) may be fixed to the concrete layer (1.2) by the rivet (1.3b); The concrete layer (1.2) is a micro-expansion concrete layer.

2. The design method for the reinforced structure according to claim 1, characterized in that, In step S1, core samples of the lining concrete are drilled from the corroded area using a core drilling machine, and the sampling rules are as follows: When the corrosion area 1m 2 One core sample was drilled from the corrosion center; When 1m 2 Corrosion area 4m 2 Three core samples were drilled in the corrosion center area, with a drill hole spacing of 1m. When the corrosion area > 4m 2 Five core samples were drilled in the corrosion center area, with a drill hole spacing of 1m.

3. The design method for the reinforced structure according to claim 1 or 2, characterized in that, Before proceeding to step S4, it is necessary to determine whether to select channel steel or corrugated plate as the reinforcement. The selection rules are as follows: When the corrosion depth of the lining concrete is greater than or equal to 10cm, channel steel is selected as the reinforcement. When the corrosion depth of the lining concrete is less than 10cm, corrugated plates are selected as the reinforcement components.

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