Method for analyzing stability of large-span tunnel bearing arch based on compression-tension safety factor

Abstract

This invention discloses a stability analysis method for the bearing arch of a large-span tunnel based on compressive and tensile safety factors, belonging to the field of tunnel and underground engineering construction data analysis technology. The method includes the following steps: obtaining the tunnel geometry, surrounding rock mechanical strength, ground stress, and support parameters; simplifying the bearing arch formed by anchor spraying reinforcement into an arched beam elastically fixed to the sidewalls at both ends; determining the plastic loosening zone of the roof slab through numerical simulation, and using its self-weight as the main vertical load; calculating the internal forces and edge normal stresses of key sections of the bearing arch using structural mechanics, and classifying them into compressive and tensile stresses accordingly; calculating the compressive and tensile safety factors of each section based on the natural strength parameters of the surrounding rock, and using the minimum value as a quantitative index for evaluating the overall stability of the bearing arch. This invention establishes a quantitative mechanical model of the bearing arch, realizing accurate and convenient assessment of the safety of the anchor spraying support structure of the roof slab of ultra-large span tunnels.

Description

Technical Field

[0001] This invention relates to the field of data analysis technology for tunnel and underground engineering construction, specifically to a method for analyzing the stability of large-span tunnel bearing arches based on compressive and tensile safety factors. Background Technology

[0002] In the field of tunnel and underground engineering, for large-span caverns using anchor-sprayed support, treating the reinforced surrounding rock as a single structural element—a load-bearing arch—for mechanical analysis is a crucial engineering concept and practical method for assessing its stability and optimizing support design. This concept involves using support methods to mobilize and enhance the strength of the surrounding rock itself, enabling it to form an arch-shaped load-bearing structure capable of supporting overlying loads. With the maturity of numerical calculation techniques, researchers can more precisely simulate the stress redistribution, plastic zone development, and anchor reinforcement mechanisms of the surrounding rock after excavation, thus providing a powerful tool for identifying the potential range of load-bearing arches and understanding their formation mechanisms. At the engineering application level, the concepts of stable arches or load-bearing arches have been proposed for specific conditions, and design is guided by engineering analogies and empirical methods.

[0003] However, as engineering demands evolve towards ultra-large span tunnels exceeding 30 meters in span, greater burial depth, and more complex geological conditions, existing analytical methods face challenges in achieving quantitative and refined design. Their limitations are mainly reflected in the following aspects: Regarding the practical application of mechanical models, there is a lack of standardized procedures for extracting numerical simulation results into a well-defined, parameter-based mechanical model of a load-bearing arch structure that can be used for direct stability verification; In terms of quantitative stability evaluation criteria, there is often an emphasis on macroscopic stability or compressive stability, failing to fully consider the weak tensile strength of rock masses and to establish a quantitative assessment system based on a dual safety factor that simultaneously covers both compressive and tensile strength.

[0004] Therefore, there is an urgent need for a comprehensive analysis method that can connect numerical analysis results with structural design calculations, perform quantitative internal force calculations on the load-bearing arch formed by anchor spraying reinforcement, and conduct quantitative safety assessments using both compressive and tensile strength criteria. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a stability analysis method for large-span tunnel bearing arches based on compressive and tensile safety factors.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The stability analysis method for large-span tunnel bearing arches based on compressive and tensile safety factors includes the following steps:

[0008] Step S1: Obtain the excavation geometry parameters, natural mechanical and strength parameters of the surrounding rock, geostress field parameters, and proposed roof support parameters for the target cavern.

[0009] Step S2: The top plate bearing arch structure reinforced by system anchors and shotcrete is simplified into an arch beam with equivalent thickness. The two ends of the arch beam are simulated with an elastic consolidation connection model to the surrounding rock of the cavern sidewall.

[0010] Step S3: Based on numerical simulation, determine the range and thickness of the plastic loosening zone above the roof after tunnel excavation, and use the self-weight of the rock mass in the plastic loosening zone as the vertical distributed load acting on the bearing arch.

[0011] Step S4: Apply structural mechanics methods to calculate the axial force and bending moment of the load-bearing arch at the key sections, and then calculate the normal stress at the inner and outer edges of each key section;

[0012] Step S5: Calculate the compressive safety factor and tensile safety factor of the bearing arch based on the natural mechanical and strength parameters of the surrounding rock, respectively;

[0013] Step S6: Take the minimum value of the compressive safety factor and tensile safety factor calculated from all key sections as the safety factor for evaluating the overall stability of the bearing arch.

[0014] Furthermore, the excavation geometric parameters include at least the tunnel span, height, crown curvature radius, and sidewall height; the natural mechanical and strength parameters of the surrounding rock include at least the rock mass, compressive strength, tensile strength, cohesion, and internal friction angle; the geostress field parameters include at least the magnitude of vertical geostress, the magnitude of horizontal geostress, and the lateral pressure coefficient calculated from both; and the roof support parameters include at least the length, diameter, spacing, and prestress value of the system anchor bolts, as well as the thickness and strength of the shotcrete.

[0015] Furthermore, in step S2, in the elastic consolidation connection model, the vertical reaction force, horizontal reaction force, and constraint bending moment can be transmitted between the arch foot of the bearing arch and the surrounding rock of the sidewall; the shape of the arch axis of the arch beam is consistent with the actual excavation outline of the cavern roof arch, and the equivalent thickness is related to the reinforcement depth of the system anchor bolts.

[0016] Furthermore, in step S3, the method for determining the thickness of the plastic loosening zone includes: performing elastoplastic analysis using finite element software, and defining the area where the tangential stress around the tunnel after excavation is less than the rock mass strength or where plastic yielding occurs as the plastic loosening zone.

[0017] Furthermore, in step S4, the key cross-section includes at least the arch crown cross-section, the two side abutment cross-sections, and the arch foot cross-section.

[0018] Furthermore, in step S4, the calculated normal stresses at the inner and outer edges of each key section are used to calculate the safety factor; where, when the normal stress is negative, the absolute value of the normal stress is the compressive stress at the edge of the bearing arch section; when the normal stress is positive, it is the tensile stress at the bearing arch section.

[0019] Furthermore, in step S5, the compressive safety factor of the bearing arch is obtained by the ratio of the compressive strength of the surrounding rock to the compressive stress at the edge of the bearing arch section, and the compressive strength of the surrounding rock is determined according to the Mohr-Coulomb strength criterion or the Hawke-Brown strength criterion.

[0020] Furthermore, in step S5, the tensile safety factor of the bearing arch is obtained by the ratio of the tensile strength of the rock mass to the tensile stress at the cross section of the bearing arch, which is determined based on the Hawke-Brown criterion.

[0021] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the stability analysis method for large-span tunnel bearing arches based on compressive and tensile safety factors as described in any one of the claims.

[0022] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the stability analysis methods for large-span tunnel bearing arches based on compressive and tensile safety factors.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. This invention simplifies the load-bearing arch into a hingeless arch model with elastically fixed arch feet, taking into account the moment transfer and constraint effects between the arch and the surrounding rock walls. Compared with the traditional three-hinged arch or simply supported assumptions, this invention more realistically reflects the actual stress state of the structure and significantly improves the accuracy of internal force calculation.

[0025] 2. This invention introduces the concept of dual safety factors of compressive and tensile strength, and performs quantitative calculations based on rock mass strength criteria, ultimately providing a clear and quantifiable overall safety factor. This changes the previous model of relying on qualitative judgment based on engineering experience, and provides a direct and reliable numerical basis for the comparison and optimization of support schemes.

[0026] 3. This invention is specifically designed to solve the stability problem of the plastic zone of the roof slab in ultra-large span, deep buried tunnels. It effectively overcomes the limitations of traditional theories in this type of project and has important value in ensuring the safety and economy of major underground projects.

[0027] 4. This invention, through rotational stiffness and horizontal resistance coefficient, realizes the transformation of boundary conditions from empirical assumptions to quantitative calculations based on the synergistic mechanism of surrounding rock and support in the analysis of bearing arches. It directly links the boundary stiffness parameters with available engineering parameters, which not only significantly improves the realism of the model's mechanical response and makes the calculation of key internal forces such as arch foot bending moment more accurate, but also quantitatively reveals the contribution of sidewall reinforcement to overall stability through parameter sensitivity analysis. Attached Figure Description

[0028] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0029] Figure 1 This is a flowchart illustrating an embodiment of the present invention;

[0030] Figure 2 This is a logic diagram of an elastic consolidation connection model according to an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram illustrating the mechanical analysis principle of the load-bearing arch in an embodiment of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] like Figure 1 As shown, the stability analysis method for large-span tunnel bearing arches based on compressive and tensile safety factors includes the following steps:

[0034] Step S1: Obtain the excavation geometry parameters, natural mechanical and strength parameters of the surrounding rock, geostress field parameters, and proposed roof support parameters for the target cavern.

[0035] Step S2: The top plate bearing arch structure reinforced by system anchors and shotcrete is simplified into an arch beam with equivalent thickness. The two ends of the arch beam are simulated with an elastic consolidation connection model to the surrounding rock of the cavern sidewall.

[0036] Step S3: Based on numerical simulation, determine the range and thickness of the plastic loosening zone above the roof after tunnel excavation, and use the self-weight of the rock mass in the plastic loosening zone as the vertical distributed load acting on the bearing arch.

[0037] Step S4: Apply structural mechanics methods to calculate the axial force and bending moment of the load-bearing arch at the key sections, and then calculate the normal stress at the inner and outer edges of each key section;

[0038] Step S5: Calculate the compressive safety factor and tensile safety factor of the bearing arch based on the natural mechanical and strength parameters of the surrounding rock, respectively;

[0039] Step S6: Take the minimum value of the compressive safety factor and tensile safety factor calculated from all key sections as the safety factor for evaluating the overall stability of the bearing arch.

[0040] The excavation geometric parameters include at least the tunnel span, height, crown curvature radius, and sidewall height; the natural mechanical and strength parameters of the surrounding rock include at least the rock mass, compressive strength, tensile strength, cohesion, and internal friction angle; the geostress field parameters include at least the magnitude of vertical geostress, the magnitude of horizontal geostress, and the lateral pressure coefficient calculated from both; the roof support parameters include at least the length, diameter, spacing, and prestress value of the system anchor bolts, as well as the thickness and strength of the shotcrete.

[0041] like Figure 2 As shown, in step S2, in the elastic consolidation connection model, the vertical reaction force, horizontal reaction force and constraint bending moment can be transmitted between the arch foot of the bearing arch and the surrounding rock of the sidewall; the shape of the arch axis of the arch beam is consistent with the actual excavation outline of the cavern top arch, and the equivalent thickness is related to the reinforcement depth of the system anchor bolts.

[0042] The elastically consolidated connection model is quantitatively simulated using two parameters: rotational stiffness and horizontal resistance coefficient. Rotational stiffness reflects the ability of the surrounding rock wall to resist the rotation of the arch foot, while the horizontal resistance coefficient reflects the ability of the surrounding rock wall to resist the horizontal displacement of the arch foot. The specific formulas are as follows:

[0043]

[0044]

[0045] in, Indicates the horizontal resistance coefficient. This represents the comprehensive constraint coefficient of the surrounding rock of the sidewall, which is dimensionless. For intact to relatively intact rock masses, it can be taken as 1.0~1.5; for rock masses with well-developed joints, it can be taken as 0.5~1.0. This represents the equivalent compression modulus of the surrounding rock near the arch foot. The width representing the influence of the load on the bearing arch can be approximated as 1.5 to 2.5 times the equivalent thickness of the bearing arch. Indicates rotational stiffness. This indicates the rotational stiffness provided by the sidewall rock mass. This indicates the additional rotational stiffness provided by the sidewall anchor.

[0046] The formula for calculating the equivalent compression modulus of the surrounding rock near the arch foot is as follows:

[0047]

[0048] in, This represents the natural deformation modulus of the surrounding rock. This represents the equivalent lateral restraint force provided by the roof support system near the arch foot. This represents the natural uniaxial compressive strength of the surrounding rock. This represents the modulus enhancement factor, with a value ranging from 0.1 to 0.3, determined through experiments or back analysis.

[0049] The equivalent lateral restraint force is calculated by distributing the average lateral restraint force perpendicular to the tunnel wall provided by all prestressed anchors and cables in the roof support system to the area of ​​the rock mass on which they act. The specific calculation process includes: determining the average working tensile force of a single anchor or cable, then multiplying the average working tensile force by a group anchor effect reduction factor to account for the possible reduction in the efficiency of multiple anchors working together, and finally dividing by the average support area of ​​a single anchor determined by the longitudinal and circumferential spacing of the single anchors in the tunnel. The group anchor effect reduction factor needs to be determined or taken as an empirical parameter based on specific engineering conditions, usually between 0.5 and 1.0, and can be determined through numerical simulation or back-calculation analysis of existing engineering data, such as being defined as a function related to anchor spacing and rock mass quality.

[0050] The formula for calculating the rotational stiffness provided by the sidewall rock mass is:

[0051]

[0052] in, Indicates the horizontal resistance coefficient. This represents the moment of inertia of the arch foot section about its neutral axis. The rotational stiffness conversion factor is related to the sidewall height and rock type, and is typically taken as 1.0 to 3.0. It can be initially estimated by establishing a simple cantilever beam bending model of the sidewall. Specifically, this involves simplifying the sidewall and surrounding rock into a cantilever beam model with the lower end fixed. The beam height is taken as the sidewall height, the beam width as the unit width, and the elastic modulus as the equivalent compression modulus of the surrounding rock. A unit bending moment is applied to the free end of the cantilever beam, i.e., the arch foot. The rotation angle generated at this end is calculated based on the principles of mechanics of materials, thus obtaining the actual rotational stiffness provided by the sidewall. Then, setting the actual rotational stiffness equal to the expression for the rotational stiffness provided by the sidewall rock mass, the theoretical value of the rotational stiffness conversion factor can be obtained. Considering that the sidewall is not an ideal cantilever beam, the actual factor can be adjusted based on the surrounding rock conditions, especially for higher sidewalls or softer surrounding rock. Take the larger value; otherwise, take the smaller value. The value can also be further verified by combining on-site displacement monitoring or numerical back analysis.

[0053] The formula for calculating the rotational stiffness provided by the sidewall anchor is as follows:

[0054]

[0055] in, This indicates the number of rows of sidewall anchor bolts involved in resisting rotation; typically, it is 1-2 rows above and below the arch foot. This indicates the shear modulus of the anchor bolt material. This represents the cross-sectional area of ​​a single anchor bolt. This indicates the effective shear resistance length of the anchor bolt within the loosened zone of the sidewall, which can be taken as the depth of the plastic loosened zone of the sidewall. This indicates the circumferential spacing of the anchor bolts in the sidewall area. This indicates the longitudinal spacing of the anchor bolts in the sidewall area.

[0056] In step S3, the method for determining the thickness of the plastic loosening zone includes: using finite element software to perform elastoplastic analysis, defining the area where the tangential stress around the tunnel after excavation is less than the rock mass strength or where plastic yielding occurs as the plastic loosening zone.

[0057] The specific process for determining the plastic loosening zone includes:

[0058] Based on the parameters obtained in step S1, a three-dimensional elastoplastic numerical model of the rock-underground structure that can reflect the entire process of cavern excavation is established. The Mohr-Coulomb model or the Hawke-Brown model should be selected as the constitutive model of the rock mass.

[0059] Obtain stress, strain, and plastic state cloud maps of the surrounding rock after excavation;

[0060] Extract the stress and plastic state of the surrounding rock along the normal direction of the arch contour. Define the continuous region that satisfies any of the following criteria as the plastic loosening zone:

[0061] 1. The material has entered the yield state (plastic strain is greater than zero); 2. The tangential stress value is lower than the reduced long-term strength threshold of the rock mass (for example, 0.5 to 0.7 times the peak strength of the rock mass); 3. Radial tensile stress appears and exceeds the tensile strength of the rock mass.

[0062] The thickness of the plastic loosening zone is defined as the normal distance from the hole wall to the boundary that satisfies the above criteria.

[0063] The equivalent thickness of the load-bearing arch is mainly determined based on the reinforcement range of the system anchors. It can usually be taken as: the effective anchorage depth of the system anchors, which is generally 2 / 3 to the full length of the anchors; or refer to the average thickness of the plastic zone or significant stress adjustment zone of the top plate revealed in the numerical simulation.

[0064] In step S4, the key sections include at least the arch crown section, the two side shoulder sections, and the arch foot section.

[0065] In step S4, the calculated normal stresses at the inner and outer edges of each key section are used to calculate the safety factor; where, when the normal stress is negative, the absolute value of the normal stress is the compressive stress at the edge of the bearing arch section; when the normal stress is positive, it is the tensile stress at the bearing arch section.

[0066] In step S5, the compressive safety factor of the bearing arch is obtained by the ratio of the compressive strength of the surrounding rock to the compressive stress at the edge of the bearing arch section. The compressive strength of the surrounding rock is determined according to the Mohr-Coulomb strength criterion or the Hawke-Brown strength criterion.

[0067] In step S5, the tensile safety factor of the bearing arch is obtained by the ratio of the tensile strength of the rock mass to the tensile stress at the cross section of the bearing arch, which is determined based on the Hawke-Brown criterion.

[0068] The distance from the centroid of the cross-section of the rod to the inner edge At that time, among them The radius corresponding to the arc along the arch axis can be calculated using the normal stress of a straight beam to obtain a solution that meets the engineering accuracy requirements.

[0069]

[0070] As shown in the above equation, the maximum and minimum values ​​of the normal stress on any cross section are located at the inner and outer edges of the section. Therefore, it is only necessary to calculate the stress at the edges. Normal stress on any cross section Indicates bending moment, Indicates axial force. Indicates span, Indicates the thickness of the load-bearing arch. Indicates the calculated width of the load-bearing arch. This represents the bending moment value in the vertical direction of the structural section.

[0071] The normal stress at the inner and outer edges of any section i of the load-bearing arch can be calculated using the following formula:

[0072]

[0073] in, This represents the lateral stress of the surrounding rock at section i of the bearing arch. This represents the lateral stress of the tunnel wall at section i of the bearing arch. This represents the bending moment at section i of the bearing arch. This represents the axial force at section i of the bearing arch.

[0074] The internal stress of the load-bearing arch is primarily compressive, but may also be tensile when there is significant settlement on the inner side of the arch crown. Furthermore, since the above model does not consider the influence of the surrounding rock's resistance on the internal forces of the load-bearing arch, under loads primarily composed of vertical loosening pressure, the constraint of the sidewalls at the arch foot is insufficient to limit the displacement of the arch foot towards the surrounding rock. Therefore, the outer side of the arch foot may also be under tension. Thus, the compressive and tensile safety factors of the load-bearing arch should be calculated separately, as the stability of the load-bearing arch depends on the smaller of the two.

[0075] The compressive strength of the surrounding rock and the compressive stress at the edge of the bearing arch section The ratio of is defined as the compressive safety factor of the bearing arch.

[0076] When using the Mohr-Coulomb criterion, the calculation formula is:

[0077]

[0078] When using the Hawke-Brown criterion, the calculation formula is:

[0079]

[0080] in, This indicates the compressive safety factor of the load-bearing arch. This represents the equivalent support reaction force provided by the anchor bolts and cables of the prestressed system. It represents the uniaxial compressive strength of intact rock material, obtained through uniaxial compression tests on intact rock cores in the laboratory. The Hawke-Brown constant represents the rock mass. This represents a constant that reflects the integrity of the rock mass.

[0081] If tensile stress is generated within the bearing arch, the tensile strength of the rock mass and the tensile stress at section i of the bearing arch can be determined using the Hawke-Brown criterion. The ratio is used to calculate the tensile safety factor of the bearing arch:

[0082]

[0083] The tensile safety factor of the bearing arch is indicated. Under tensile conditions, the Mohr-Coulomb criterion will seriously exaggerate the strength of the rock mass and should not be used.

[0084] If the tensile strength of the rock mass can be obtained by other means, it can also be divided by the tensile stress to calculate the tensile safety factor of the bearing arch.

[0085] It should be noted that when calculating the safety factor, the strength parameters of the surrounding rock of the bearing arch should all be the strength indices of the natural rock mass, and the strength indices of the surrounding rock after prestressed anchor bolts or anchor cables should not be used.

[0086] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the stability analysis method for large-span tunnel bearing arches based on compressive and tensile safety factors as described in any one of the claims.

[0087] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the stability analysis methods for large-span tunnel bearing arches based on compressive and tensile safety factors.

[0088] like Figure 3 As shown, this invention transforms complex engineering problems into computable mechanical models and performs quantitative stability assessments based on its core principles and processes. Its content can be divided into three logically connected parts, specifically including:

[0089] 1. Actual engineering scenario. From the start of the excavation of the super-large span tunnel, the excavation disturbance causes the roof rock mass to generate a plastic zone that needs attention, and the anchor spray support reinforces it into a load-bearing arch structure to be analyzed.

[0090] 2. Mechanical Model Abstraction. The complex rock mass structure formed by anchor spraying reinforcement is simplified into an elastically consolidated hingeless arch. The core of this model is the elastically consolidated connection between the arch foot and the sidewall. The load is then determined, with the weight of the plastic loosening zone identified in the first part serving as the main external load. Finally, based on this model and the load, the internal forces of key sections are solved using structural mechanics methods, providing input for subsequent analysis.

[0091] 3. Core of Quantitative Stability Analysis. The internal forces obtained in Part Two are used to calculate the edge stress of the cross-section. Next, the stress state is determined: if it is compressive stress, the compressive safety factor is calculated; if it is tensile stress, the tensile safety factor is calculated. Finally, the overall safety factor is obtained by taking the minimum value, which serves as the final quantitative indicator of stability.

[0092] Any combination of one or more computer-readable media may be used. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in connection with an instruction execution system, apparatus, or device.

[0093] The examples described herein are merely preferred embodiments of the invention and are not intended to limit the concept and scope of the invention. Any modifications and improvements made by those skilled in the art to the technical solutions of the invention without departing from the design concept of the invention should fall within the protection scope of the invention.

Claims

1. A method for analyzing the stability of a bearing arch of a large-span tunnel based on a compressive and tensile safety factor, characterized in that, Includes the following steps: Step S1: Obtain the excavation geometry parameters, natural mechanical and strength parameters of the surrounding rock, geostress field parameters, and proposed roof support parameters for the target cavern. Step S2: The top slab bearing arch structure reinforced by system anchors and shotcrete is simplified into an arch beam with equivalent thickness. The two ends of the arch beam are simulated with an elastic consolidation connection model to the surrounding rock of the cavern sidewall. The equivalent thickness of the bearing arch is determined according to the reinforcement range of the system anchors. In the elastic consolidation connection model, the vertical reaction force, horizontal reaction force and constraint bending moment can be transmitted between the arch foot of the bearing arch and the surrounding rock of the sidewall. Step S3: Determine the range and thickness of the plastic loosening zone above the tunnel roof after excavation based on numerical simulation, and use the self-weight of the rock mass in the plastic loosening zone as the vertical distributed load acting on the bearing arch; wherein, the method for determining the thickness of the plastic loosening zone includes: using finite element software to perform elastoplastic analysis, defining the area where the tangential stress around the tunnel after excavation is less than the rock mass strength or where plastic yielding occurs as the plastic loosening zone; Step S4: Apply structural mechanics methods to calculate the axial force and bending moment of the bearing arch at the critical sections, and then calculate the normal stress at the inner and outer edges of each critical section; the critical sections include at least the arch crown section, the two side arch shoulder sections, and the arch foot section; the calculated normal stress at the inner and outer edges of each critical section is used to calculate the safety factor; where, when the normal stress is negative, the absolute value of the normal stress is the compressive stress at the edge of the bearing arch section; when the normal stress is positive, it is the tensile stress at the bearing arch section; Step S5: Calculate the compressive safety factor and tensile safety factor of the bearing arch based on the natural mechanical and strength parameters of the surrounding rock. The compressive safety factor of the bearing arch is obtained by the ratio of the compressive strength of the surrounding rock to the compressive stress at the edge of the bearing arch section. The compressive strength of the surrounding rock is determined according to the Mohr-Coulomb strength criterion or the Hawke-Brown strength criterion. The tensile safety factor of the bearing arch is obtained by the ratio of the tensile strength of the rock mass determined based on the Hawke-Brown criterion to the tensile stress at the bearing arch section. Step S6: Take the minimum value of the compressive safety factor and tensile safety factor calculated from all key sections as the safety factor for evaluating the overall stability of the bearing arch.

2. The stability analysis method for large-span tunnel bearing arches based on compressive and tensile safety factors according to claim 1, characterized in that, The excavation geometric parameters include at least the tunnel span, height, crown curvature radius, and sidewall height; the natural mechanical and strength parameters of the surrounding rock include at least the rock mass, compressive strength, tensile strength, cohesion, and internal friction angle; the geostress field parameters include at least the magnitude of vertical geostress, the magnitude of horizontal geostress, and the lateral pressure coefficient calculated from both; the roof support parameters include at least the length, diameter, spacing, and prestress value of the system anchor bolts, as well as the thickness and strength of the shotcrete.

3. The stability analysis method for large-span tunnel bearing arches based on compressive and tensile safety factors according to claim 2, characterized in that, In step S2, the shape of the arch axis of the arch beam is consistent with the actual excavation outline of the cavern arch, and the equivalent thickness is related to the reinforcement depth of the system anchor bolts.

4. An electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the stability analysis method for large-span tunnel bearing arches based on compressive and tensile safety factors as described in any one of claims 1 to 3.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the stability analysis method for large-span tunnel bearing arches based on compressive and tensile safety factors as described in any one of claims 1 to 3.

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