A tunnel support bearing capacity calculation method, system, device and storage medium

Abstract

This invention discloses a method, system, equipment, and storage medium for calculating the bearing capacity of tunnel support, relating to the field of tunnel engineering support technology. The method for calculating the bearing capacity of tunnel support in this invention achieves accurate calculation of bearing capacity through a three-step progressive model: stirrup constraint section division, stirrup constraint effect quantification analysis, and ultimate bearing capacity combination calculation. First, ineffective and effective constraint regions are divided and control sections are determined, and the area of ​​each region is calculated. Then, the effective constraint effect coefficient is used to quantify the constraint influence, obtaining the increase in concrete compressive strength and the increment of axial compression ultimate bearing capacity. Finally, the ultimate bearing capacity is calculated using standard formulas. This invention can accurately determine the bearing capacity, fully utilize the performance of the support structure, and has universality, applicable to various types of tunnel engineering.

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: Perform quantitative analysis of the stirrup constraint effect, using the effective constraint effect coefficient. This indicates the effect of the stirrups on the confinement of concrete, and calculates the increase in compressive strength f of the concrete in the effective confinement core area of ​​the stirrup-confined member. cc This leads to the increment ΔN of the axial compressive ultimate bearing capacity of the stirrup-confined steel-concrete composite member;

[0010] Step S3: Perform ultimate bearing capacity combination calculation, and combine the calculation formula of ultimate bearing capacity of steel-concrete composite support to obtain the ultimate bearing capacity N of steel-concrete composite support under stirrup constraint.

[0011] Furthermore, in this invention, in step S1 above, the area A1 of the non-effective constraint region is calculated according to the following formula:

[0012]

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

[0014] Furthermore, in this invention, in step S1 above, the area of ​​the effective constraint region... Calculate using the following formula:

[0015]

[0016]

[0017] calculate In the formula, denoted as the cross-sectional area of ​​the I-beam, and 'a' is the transverse spacing of the stirrups along their centerlines.

[0018] The control cross-sectional area Calculate using the following formula:

[0019]

[0020] In the formula for calculating Ae, s is the stirrup spacing.

[0021] Furthermore, in this invention, in step S2 above, the effective constraint effect coefficient Calculate using the following formula:

[0022]

[0023]

[0024] calculate In the formula, This represents the area ratio of the axial stirrups. It represents the total cross-sectional area of ​​the stirrups between two adjacent stirrups in the axial direction.

[0025] Furthermore, in this invention, in step S2 above, the f cc Calculate using the following formula:

[0026]

[0027] Calculate f cc In the formula, f c This refers to the axial compressive strength of concrete.

[0028] For a rectangular axially compressed steel-concrete composite member, the lateral restraint force f under the stirrup constraint in the x-direction is... x Calculate using the following formula:

[0029]

[0030] Calculate f x In the formula, f cv The stirrup yield strength;

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

[0032] .

[0033] Furthermore, in this invention, in step S3 above, the ultimate bearing capacity N of the steel-concrete composite support under stirrup constraint is calculated according to the following formula:

[0034]

[0035] In the formula for calculating N, N c To disregard the load borne by the concrete under the constraint of stirrups, N a For the load borne by the steel section, A c f is the net cross-sectional area of ​​the concrete. a φ represents the yield strength of the steel section, and φ is the axial compressive stability coefficient.

[0036] Furthermore, in this invention, in step S1 described above, the controlled section is the section at the midpoint between two longitudinal stirrups, where the constraint effect is weakest and the section loss rate is greatest.

[0037] Secondly, the present invention also provides a system for determining the bearing capacity of stirrup-restrained tunnel support, comprising:

[0038] 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 The net cross-sectional area of ​​concrete A c Yield strength f of structural steel a φ, the axial compressive stability coefficient;

[0039] 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 above calculation method based on the basic parameters.

[0040] Thirdly, the present invention also provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the tunnel support bearing capacity calculation method described above.

[0041] Fourthly, the present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the above-described method for calculating the bearing capacity of tunnel support.

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

[0043] The tunnel support bearing capacity calculation method, system, equipment, and storage medium of this invention calculate the bearing capacity of stirrup-constrained tunnel support by comprehensively considering factors such as stirrups, steel sections, concrete mechanical performance parameters, and stirrup constraint range. This solves the problem of neglecting the constraint contribution of stirrups in existing formulas, accurately determining the bearing capacity of stirrup-constrained tunnel support, thereby maximizing the good synergistic deformation and shared bearing capacity of stirrup-constrained tunnel support. This invention is universally applicable; it can calculate the bearing capacity of a specific stirrup-constrained tunnel support in the tunnel field, and is not limited to a particular tunnel project. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. 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, we can obtain =0.00869m².

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

[0060]

[0061] Substituting the data, we can obtain =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 formula Calculate the effective constraint effect coefficient According to the formula Calculate the lateral constraint force f x .

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076] According to the formula Calculate the increase in compressive strength f of concrete in the effectively constrained core area. cc ,

[0077]

[0078]

[0079]

[0080] f of components 1, 2, and 3 cc The values ​​are 28.74 MPa, 42.47 MPa, and 69.17 MPa, respectively.

[0081] According to the formula Calculate the increment ΔN of the ultimate bearing capacity under axial compression.

[0082]

[0083]

[0084]

[0085] The ΔN values ​​for components 1, 2, and 3 are 20.12 kN, 58.56 kN, and 154.74 kN, respectively.

[0086] 3. Ultimate bearing capacity combination calculation

[0087] Net cross-sectional area of ​​concrete A c The area is 0.0384 m², and the yield strength f of the steel section is... a The pressure is 259.62 MPa, and the axial compressive 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 segment 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] Example 3

[0099] This embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the tunnel support bearing capacity calculation method as described in Embodiment 1.

[0100] Example 4

[0101] This embodiment provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the steps of the tunnel support bearing capacity calculation method of Embodiment 1.

[0102] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. 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 method for calculating the bearing capacity of tunnel support, characterized in that, Includes the following steps: 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 area and an effective confinement area, and define the weaker confinement area within the effective confinement area as the control section; calculate the area A1 of the ineffective confinement area, the area A0 of the effective confinement area, and the area Ae of the control section. Step S2: Perform quantitative analysis of the confinement effect of stirrups, use the effective confinement effect coefficient Ke to represent the effect of confinement on concrete, calculate the increase in compressive strength fcc of concrete in the effective confinement core area of ​​the stirrup-confined member, and then obtain the increment ΔN of the axial compression ultimate bearing capacity of the stirrup-confined steel-concrete member. Step S3: Perform ultimate bearing capacity combination calculation. Using the formula for calculating the ultimate bearing capacity of steel-concrete composite support, obtain the ultimate bearing capacity N of steel-concrete composite support under stirrup confinement. In step S1, the area A1 of the non-effective constraint region is calculated according to the following formula: In the formula for calculating A1, d is the distance between the centerlines of the upper and lower stirrups on the plane section, Φ is the diameter of the stirrup, and α1 is the angle between the inner surface of the stirrup and the constraint boundary line. In step S1, the effective constraint area A0 is calculated according to the following formula: A = ad A0=A-2A1-A a In the formula for calculating A0, Aa is the cross-sectional area of ​​the I-beam, and a is the transverse spacing of the stirrup centerlines; The control cross-sectional area Ae is calculated according to the following formula: In the formula for calculating Ae, s is the stirrup spacing. In step S2, the effective constraint effect coefficient Ke is calculated according to the following formula: In the formula for calculating Ke, ρx is the area ratio of the axial stirrups, and Ax is the total cross-sectional area of ​​the stirrups between two adjacent axial stirrups. In step S3, the ultimate bearing capacity N of the steel-concrete composite support under stirrup confinement is calculated according to the following formula: In the formula for calculating N, Nc is the load borne by the concrete without considering the restraint of the stirrups, Na is the load borne by the steel section, Ac is the net cross-sectional area of ​​the concrete, fa is the yield strength of the steel section, and φ is the axial compressive stability coefficient.

2. The method for calculating the bearing capacity of tunnel support according to claim 1, characterized in that, In step S2, the fcc is calculated according to the following formula: In the formula for calculating fcc, fc is the axial compressive strength of concrete. For a rectangular axially compressed steel-concrete composite member, the lateral restraint force fx under stirrup confinement in the x-direction is calculated using the following formula: f x =K e r x f cv In the formula for calculating fx, fcv is the yield strength of the stirrup; The increment ΔN of the axial compression ultimate bearing capacity is calculated according to the following formula. ΔN=f cc A e 。 3. The method for calculating the bearing capacity of tunnel support according to claim 1, characterized in that, In step S1, the control section is the section at the midpoint between the two longitudinal stirrups, where the constraint effect is weakest and the section loss rate is greatest.

4. A system for determining the bearing capacity of stirrup-constrained tunnel support, characterized in that, include: 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, the cross-sectional area Aa of the I-beam, the transverse spacing a of the centerlines of the stirrups, the stirrup spacing s, the total cross-sectional area Ax of the stirrups between two adjacent stirrups in the axial direction, the axial compressive strength fc of the concrete, the yield strength fcv of the stirrup, the net cross-sectional area Ac of the concrete, the yield strength fa of the steel, and the axial compressive stability coefficient φ. 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 described in claim 1, based on the basic parameters.

5. An electronic device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the tunnel support bearing capacity calculation method as described in claim 1.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the tunnel support bearing capacity calculation method as described in claim 1.

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