Tunnel support bearing capacity calculation method, system and equipment and storage medium

Abstract

The invention discloses a tunnel support bearing capacity calculation method, system and equipment and a storage medium, and relates to the technical field of tunnel engineering support. According to the method for calculating the bearing capacity of the tunnel support, accurate calculation of the bearing capacity is achieved through a three-step progressive model including stirrup constraint section division, stirrup constraint effect quantitative analysis and ultimate bearing capacity combination calculation. Firstly, non-effective and effective constraint regions are divided, a control section is determined, and the area of each region is calculated; then, the constraint influence is quantified by adopting an effective constraint effect coefficient, and the concrete compressive strength improvement amplitude and the axial pressure ultimate bearing capacity increment are obtained; and finally calculating the ultimate bearing capacity in combination with a standard formula. The method can accurately determine the bearing capacity, gives full play to the performance of a supporting structure, has universality and is suitable for various tunnel projects.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering support technology, specifically to a method, system, equipment, and storage medium for calculating the bearing capacity of tunnel support. Background Technology

[0002] With the continuous advancement of transportation infrastructure construction in my country, the number of long and deep-buried tunnels is increasing daily. During tunnel construction, complex geological conditions can easily lead to engineering disasters such as tunnel deformation, shotcrete spalling, and secondary lining cracking, which seriously threaten construction safety.

[0003] To address the aforementioned issues, steel-shotcrete structures have been widely used in the initial support of tunnels due to their timely support capabilities. However, because the surface of the steel arch is relatively smooth, the natural bonding performance between the steel arch and the shotcrete is poor. Under high surrounding rock loads, the two are prone to relative delamination, which greatly affects the cooperative deformation capacity and joint load-bearing capacity of the support structure.

[0004] To improve the initial support's bearing capacity, the project employed circumferentially arranged stirrups on the steel flanges to enhance the bond between concrete and steel, thereby increasing the stiffness and bearing capacity of the steel-concrete composite structure. This reduces relative spalling between the steel and shotcrete, improving the safety and economy of tunnel construction. However, the design of stirrup-constrained steel-concrete composite supports currently faces the challenge of determining the bearing capacity under multiple factors. Accurate and effective calculation methods for the bearing capacity of stirrup-constrained tunnel supports are lacking, and most methods rely on empirical selection, failing to fully utilize the superior performance of stirrup-constrained tunnel supports. Summary of the Invention

[0005] The tunnel support bearing capacity calculation method, system, equipment, and storage medium of the present invention are used to solve the problem that in the prior art, the bearing capacity of stirrup-confined tunnel support is selected based on experience, which makes it impossible to accurately determine its bearing capacity and to maximize the good synergistic deformation and joint bearing capacity of stirrup-confined tunnel support.

[0006] This invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a method for calculating the bearing capacity of tunnel support, which includes the following steps:

[0008] Step S1: Divide the stirrup-constrained section. Considering the confinement effect of the stirrups, divide the section of the steel-concrete composite support into an ineffective confinement region and an effective confinement region, and define the weaker confinement region within the effective confinement region as the control section; calculate the area of ​​the ineffective confinement region. Effective constrained area and control cross-sectional area ;

[0009] Step S2: Quantitative analysis of stirrup constraint effect is carried out, effective constraint effect coefficient represents the constraint effect on concrete, the effective constraint core zone of the stirrup constraint component is calculated to improve the amplitude f cc , and then the increment ΔN of the axial compression ultimate bearing capacity of the stirrup constraint type steel-concrete component is obtained.

[0010] Step S3: combination calculation of ultimate bearing capacity is carried out, the ultimate bearing capacity calculation formula of the steel-concrete composite support is combined to obtain the ultimate bearing capacity N of the steel-concrete composite support under the constraint of the stirrup.

[0011] Further, in the present application, the above non-effective constraint area A1 in step S1 is calculated according to the following formula:

[0012]

[0013] The formula for calculating In the formula, d is the center line distance of the upper and lower stirrups on the plane section, Φ is the diameter of the stirrup, and α1 is the included angle between the inner surface of the stirrup and the constraint boundary line.

[0014] Further, in the present application, the above effective constraint area in step S1 is calculated according to the following formula:

[0015]

[0016]

[0017] The formula for calculating In the formula, is the cross-sectional area of the H-shaped steel, and a is the transverse spacing of the center line of the stirrup.

[0018] The control section area is calculated according to the following formula:

[0019]

[0020] The formula for calculating Ae is that s is the spacing of the stirrup.

[0021] Further, in the present application, the above effective constraint effect coefficient in step S2 is calculated according to the following formula:

[0022]

[0023]

[0024] Calculation wherein, is the area ratio of the axial stirrup, is the total cross-sectional area of the axial stirrup between two adjacent stirrups.

[0025] Further, in the present application, the f cc is calculated according to the following formula:

[0026]

[0027] The f cc is calculated according to the following formula: c is the axial compressive strength of the concrete,

[0028] For a rectangular steel reinforced concrete member, the lateral restraint force f x is calculated according to the following formula:

[0029]

[0030] The f x is calculated according to the following formula: cv is the yield strength of the stirrup;

[0031] The increment ΔN of the axial compression ultimate bearing capacity is calculated according to the following formula,

[0032] .

[0033] Further, in the present application, the steel reinforced concrete composite support ultimate bearing capacity N under the restraint of the stirrup in the step S3 is calculated according to the following formula:

[0034]

[0035] The formula for calculating N is as follows: N c is the load borne by the concrete without considering the restraint of the stirrup, N a is the load borne by the steel, A c is the net cross-sectional area of the concrete, f a is the yield strength of the steel, and φ is the axial compression stability coefficient.

[0036] Further, in the present application, the control section in the step S1 is the section at the middle position between the two longitudinal stirrups, which has the weakest restraint and the largest section loss rate.

[0037] In a second aspect, the present application also provides a system for determining the bearing capacity of a tunnel support under the restraint of a stirrup, which comprises:

[0038] The acquisition unit is used for acquiring basic parameters, including the center line distance d of the upper and lower stirrups on the plane section, the diameter of the stirrup, the included angle between the inner surface of the stirrup and the constraint boundary line, the cross-sectional area of the I-shaped steel The transverse spacing a of the stirrup center line, the spacing s of the stirrups, and the total cross-sectional area of the stirrups between two adjacent stirrups in the axial direction The axial compressive strength f of the concrete c The yield strength f of the stirrup cv The net cross-sectional area A of the concrete c The yield strength f of the steel a The axial compression stability coefficient φ.

[0039] The calculation unit is connected with the acquisition unit and is used for calculating the ultimate bearing capacity of the steel reinforced concrete combined support under the constraint of the stirrups according to the above calculation method according to the basic parameters.

[0040] In a third aspect, the present application also provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the tunnel support bearing capacity calculation method when executing the computer program.

[0041] In a fourth aspect, the present application also provides a computer readable storage medium, which stores a computer program, and the steps of the tunnel support bearing capacity calculation method are implemented when the computer program is executed by a processor.

[0042] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0043] The tunnel support bearing capacity calculation method, system, device and storage medium of the present application calculate the bearing capacity of the stirrup-constrained tunnel support by comprehensively considering the mechanical performance parameters of the stirrups, the steel and the concrete, the constraint range of the stirrups and other factors, solve the problem of ignoring the contribution of the stirrup constraint in the existing formula, and can accurately determine the bearing capacity of the stirrup-constrained tunnel support, thereby maximizing the better synergistic deformation and common bearing capacity of the stirrup-constrained tunnel support. The present application has universality and can calculate a specific bearing capacity of the stirrup-constrained tunnel support in the field of tunnels, and is not limited to a specific tunnel project. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the example embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be considered as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor. In the drawings:

[0045] Figure 1 A simplified diagram of the region division for the component;

[0046] Figure 2 Here are schematic diagrams of the cross-sections of each component;

[0047] Figure 3 A schematic diagram of the measured load-displacement curves for each component. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0049] The following detailed description of embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0050] Example 1

[0051] Embodiment 1 of the present invention provides a method for calculating the bearing capacity of stirrup-restrained tunnel support, combined with Figures 1 to 3 As shown, the specific method is described below.

[0052] In this embodiment, combined with Figure 2 As shown, the width × height × length of the steel-concrete composite member is ( The dimensions are 0.16m × 0.24m × 0.6m. The I-beam is made of I18 steel with dimensions of 0.18m × 0.094m × 0.0065mm and a length of 0.6mm. The stirrups are made of HRB400 steel bars with a diameter of 0.01m. Four working conditions are set up with stirrup spacing of 0.15m, 0.1m, 0.05m and a control group without stirrups. The stirrups are welded to the flange of the steel section.

[0053] 1. Stirrup-constrained section division

[0054] Combination Figure 1 As shown, considering the constraint effect of the stirrups, the cross-section is divided into ineffective and effective constraint regions. The weaker constraint region within the effective constraint region is defined as the control section, which is the section at the midpoint between two longitudinal stirrups, where the constraint effect is weakest and the section loss rate is greatest. The distance d between the centerlines of the upper and lower stirrups in the plane section is 0.2m, the stirrup diameter Φ is 0.01m, the angle α1 between the inner surface of the stirrup and the constraint boundary line is 55°, and the cross-sectional area of ​​the I-beam is... The area is 0.00234 m², and the transverse spacing a of the centerline of the stirrups is 0.114 m.

[0055] The distance d between the centerlines of the upper and lower stirrups in the plane section is 0.2m, and the transverse spacing a between the centerlines of the stirrups is 0.114m. It is the total area of ​​the confined zone formed by the centerlines of the upper and lower stirrups and the lateral spacing between the centerlines of the stirrups on the plane section.

[0056] According to the formula Calculate the area of ​​the ineffective constraint region ,

[0057] ,

[0058] Substituting the data yields =0.00869m².

[0059] According to the formula and formula Calculate the area of ​​the effective constraint region ,

[0060]

[0061] Substituting the data yields =0.00327m².

[0062] According to the formula Calculate the control section area :

[0063]

[0064]

[0065]

[0066] For component 1 (stirrup spacing 0.15m), substituting the data yields... =0.0007m²; For member 2 (stirrup spacing 0.1m), we can obtain =0.00138m²; For member 3 (stirrup spacing 0.05m), we can obtain =0.00224m².

[0067] 2. Quantitative Analysis of Stirrup Constraint Effect

[0068] The total cross-sectional area of ​​the stirrups between two adjacent stirrups in the axial direction The axial compressive strength of concrete is 0.0036 m². c The stress is 19.1 MPa; the yield strength of the stirrups is f. cv It is 398.56 MPa.

[0069] According to the formula And the formula The effective constraint effect coefficient , according to the formula The lateral constraint force f x .

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076] According to the formula The effective constraint core zone concrete compressive strength improvement amplitude f cc ,

[0077]

[0078]

[0079]

[0080] The f cc of the components 1, 2, 3 is 28.74 MPa, 42.47 MPa, 69.17 MPa respectively.

[0081] According to the formula The axial compression ultimate bearing capacity increment ΔN is calculated,

[0082]

[0083]

[0084]

[0085] The ΔN of the components 1, 2, 3 is 20.12 kN, 58.56 kN, 154.74 kN respectively.

[0086] 3. Ultimate bearing capacity combination calculation

[0087] The concrete net section area A c is 0.0384 m², the yield strength f a of the profile steel is 259.62 MPa, and the axial compression stability coefficient φ is 1.

[0088] According to the formula The ultimate bearing capacity N is calculated. The N values ​​for components 1, 2, and 3 are 1227 kN, 1265 kN, and 1362 kN, respectively.

[0089] 4. Experimental verification

[0090] Specimens 1-4 were loaded using a YAE-10000 electro-hydraulic servo long column compression testing machine. Axial pressure was applied from the bottom up using a jack at the loading end to simulate actual axial compression conditions, thereby testing the load-bearing capacity of the components. Before formal loading, a laser line projector was used to align the midpoint of the component with the loading midpoint on the testing machine; then, 15% of the estimated ultimate load Pmax was applied to the component. During formal loading, load control was used until the axial pressure reached 0.7Pmax; after reaching 0.7Pmax, displacement control was switched to continue loading, and the test was stopped when the component reached the extended plateau section of the load-displacement curve.

[0091] The measured ultimate bearing capacities of components 1, 2, and 3 were 1245 kN, 1285 kN, and 1351 kN, respectively. The comparison results between the experimental results and the method of this invention are shown in the table below:

[0092]

[0093] Based on the data analysis in the table above, and combined with... Figure 3 It can be seen that the ultimate bearing capacity obtained by the method of the present invention has an average error of 1.3% compared with the experimental value, which has high calculation accuracy and good agreement with the experimental results.

[0094] Example 2

[0095] This embodiment provides a system for determining the bearing capacity of stirrup-restrained tunnel support, including:

[0096] Acquisition Unit: Used to acquire basic parameters, including the distance d between the centerlines of the upper and lower stirrups on the plane section, the stirrup diameter Φ, the angle α1 between the inner surface of the stirrup and the constraint boundary line, and the cross-sectional area of ​​the I-beam. 1. The transverse spacing 'a' of the stirrup centerline; 2. The stirrup spacing 's'; 3. The total cross-sectional area of ​​the stirrups between two adjacent stirrups along the axial direction. axial compressive strength of concrete f c , stirrup yield strength f cv Net cross-sectional area of ​​concrete Yield strength f of structural steel a φ, the axial compressive stability coefficient;

[0097] Calculation unit: connected to the acquisition unit, used to calculate the ultimate bearing capacity of steel-concrete composite support under stirrup constraint according to the calculation method of Example 1 based on the basic parameters.

[0098] Embodiment 3

[0099] The embodiment provides an electronic device, including a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the tunnel support bearing capacity calculation method according to the embodiment 1 when executing the computer program.

[0100] Embodiment 4

[0101] The embodiment provides a computer readable storage medium, the computer readable storage medium stores a computer program, and the computer program implements the steps of the tunnel support bearing capacity calculation method according to the embodiment 1 when executed by a processor.

[0102] The above detailed description of the specific embodiments, the purpose, technical solutions and beneficial effects of the present application are further described in detail, and it should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application, and any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method of calculating a load bearing capacity of a tunnel support, characterized by, The method comprises the following steps: Step S1: Perform stirrup constraint section division. Considering the constraint effect of the stirrup, the section of the steel reinforced concrete composite support is divided into non-effective constraint area and effective constraint area, and the weaker constraint area in the effective constraint area is defined as the control section; the non-effective constraint area , the effective constraint area , and the control section area are calculated; Step S2: Perform stirrup constraint effect quantification analysis, adopt effective constraint effect coefficient to represent the constraint effect on concrete, calculate the increase range of effective constraint core zone concrete compressive strength of the stirrup constrained member , and further obtain the increment of the axial compression ultimate bearing capacity of the stirrup constrained steel-concrete member ; Step S3: performing limit bearing capacity combination calculation, combining the steel reinforced concrete composite support limit bearing capacity calculation formula to obtain the limit bearing capacity N of the steel reinforced concrete composite support under the constraint of the stirrups.

2. The tunnel support bearing capacity calculation method according to claim 1, characterized by, In step S1, the non-active constraint area is calculated according to the following equation: ， The calculation is as follows: where d is the distance between the center lines of the upper and lower stirrups, Φ is the diameter of the stirrups, and α1 is the angle between the inner surface of the stirrups and the boundary line of the constraint.

3. The tunnel support bearing capacity calculation method according to claim 2, characterized by, In step S1, the effective constraint area is calculated according to the following equation: ， ， Computing wherein, A is the cross-sectional area of the H-shaped steel, and a is the transverse spacing of the center line of the stirrup. The control cross-sectional area Is calculated by the following equation: ， Computing where s is the spacing between stirrups.

4. The tunnel support bearing capacity calculation method according to claim 1, characterized by, In step S2, the effective constraint effect coefficient is calculated as follows: ， ， The calculation In the formula, is the area of the axial stirrup, is the total cross-sectional area of the axial stirrup between two adjacent stirrups.

5. The method of claim 1, wherein, In step S2, the f cc is calculated according to the following equation: ， The calculation of f cc In the formula, f c is the axial compressive strength of concrete, For rectangular axial compression steel reinforced concrete components, the lateral restraint force f under the restraint of x direction stirrup x It is calculated according to the following formula: ， f = f x where f cv is the yield strength of the stirrup The increment ΔN of the shaft pressure limit bearing capacity is calculated according to the following formula, 。 6. The tunnel support bearing capacity calculation method according to claim 1, wherein, In step S3, the limit bearing capacity N of the steel reinforced concrete composite support under the constraint of the stirrups is calculated according to the following formula: ， In the formula for calculating N, N c is the load borne by the concrete without considering the restraining effect of the stirrups, a is the load borne by the steel section, c is the net sectional area of the concrete, a is the yield strength of the steel section, and φ is the axial compression stability coefficient.

7. The method of claim 1, wherein, In the step S1, the control section is the section at the middle position between the two longitudinal stirrups, which has the weakest constraint and the largest section loss rate.

8. A system for determining the load bearing capacity of a tendon-restrained tunnel support, comprising: The method comprises the following steps: The acquisition unit is used for acquiring basic parameters, including the distance d of the center line of the upper and lower stirrups on the plane section, the diameter Φ of the stirrup, the angle α1 between the inner surface of the stirrup and the constraint boundary line, the cross-sectional area of the I-shaped steel , the transverse spacing a of the center line of the stirrup, the spacing s of the stirrups, the total cross-sectional area of the stirrups between two adjacent stirrups in the axial direction , the axial compressive strength f of the concrete c , the yield strength f of the stirrup cv , the net cross-sectional area A of the concrete c , the yield strength f of the I-shaped steel a , and the axial compression stability coefficient φ. The calculation unit is connected with the acquisition unit and is used for calculating the limit bearing capacity of the steel reinforced concrete composite support under the constraint of the stirrups according to the calculation method of claim 1 based on the basic parameters.

9. An electronic device, comprising: The computer readable storage medium stores a computer program, and the computer program is executed by the processor to realize the steps of the tunnel support bearing capacity calculation method of claim 1.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to realize the steps of the tunnel support bearing capacity calculation method of claim 1.

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