Ultralight pressure relief arch frame and its design method

Abstract

This invention discloses an ultralight pressure-yielding arch frame and its design method, belonging to the field of underground engineering support. The ultralight pressure-yielding arch frame is composed of multiple overlapping segments, forming an overall arched structure. Each segment is manufactured from lightweight, high-performance steel using an integrated bending process. The overlapping nodes of the ultralight pressure-yielding arch frame are connected and fixed by cable clamping assemblies, forming pressure-yielding nodes capable of pressure-yielding sliding. The ultralight pressure-yielding arch frame of this invention features simple manufacturing process, high load-bearing capacity, light weight, and high construction efficiency.

Description

Technical Field

[0001] This invention relates to the field of underground engineering support, and in particular to an ultra-lightweight pressure-relief arch frame and its design method. Background Technology

[0002] Traditional underground engineering support often uses steel arch frames or concrete support structures, but these have the following shortcomings:

[0003] 1. Fixed stiffness and poor adaptability: Traditional arch frames cannot adjust their stiffness according to the surrounding rock conditions, which can easily lead to excessive stiffness or excessive softness.

[0004] 2. Low load-bearing efficiency: Lack of optimized design for key nodes and non-uniform stiffness, resulting in uneven overall stress distribution.

[0005] 3. Insufficient economic efficiency: Relying solely on high-strength materials or increasing the cross-section leads to material waste.

[0006] 4. Outdated design methods: They rely heavily on experience and lack systematic design theories and experimental verification.

[0007] In recent years, confined concrete arch frames have been studied and applied in tunnels with weak surrounding rock. A system design approach based on external load calculation models, internal force distribution, and bearing strength criteria has been proposed, achieving good results. However, this system still mainly uses ordinary concrete or steel and has not fully utilized the advantages of lightweight, high-strength materials and the pressure-relief mechanism. Summary of the Invention

[0008] To address the problems of existing technologies, this invention provides an ultralight pressure-relief arch frame and its design method, which features simple manufacturing process, strong load-bearing capacity, light weight, and high construction efficiency.

[0009] The technical solution provided by this invention is as follows:

[0010] An ultralight pressure-relief arch frame is provided, which is composed of multiple overlapping segments and has an overall arch-shaped structure. Each segment is made of lightweight high-performance steel through an integrated bending process. The overlapping nodes of the ultralight pressure-relief arch frame are connected and fixed by a cable clamping assembly to form a pressure-relief node that can realize pressure-relief sliding.

[0011] A design method for an ultralight pressure-relief arch frame, the method comprising:

[0012] S1: Based on the on-site engineering geological conditions, obtain the cross-sectional parameters of the chamber, the distribution of ground stress and the mechanical properties of the surrounding rock, establish a geomechanical simulation model, and determine the design value of the arch bearing capacity;

[0013] S2: Taking the ultra-lightweight pressure-yielding arch frame as the design object, based on the underground engineering geological conditions and design parameters, a mechanical calculation model of the ultra-lightweight pressure-yielding arch frame is established, the internal force calculation formula of the ultra-lightweight pressure-yielding arch frame is derived, and the internal force distribution characteristics are clarified.

[0014] S3: Based on the internal force distribution characteristics, design the node parameters of the ultra-lightweight pressure relief arch frame, arrange pressure relief nodes at key slip points where the bending moment is less than the set threshold, and design the number, location and torque of the pressure relief nodes;

[0015] S4: Conduct eccentric pressure mechanical tests on ultra-lightweight pressure-yielding arch frame components, determine the bearing strength criterion, calculate the ultimate bearing capacity of ultra-lightweight pressure-yielding arch frames under different selection conditions, and clarify the critical bearing state of ultra-lightweight pressure-yielding arch frames in conjunction with the bearing strength criterion.

[0016] S5: Introduce a comprehensive evaluation index for support, and determine the optimal design parameters by comprehensively considering material cost, cross-sectional area and density, while ensuring that the ultimate bearing capacity is higher than the design value.

[0017] Furthermore, the ultralight pressure-relief arch frame mechanical calculation model includes an external load distribution model and an arch frame structural mechanical model.

[0018] Furthermore, the torque F at the pressure relief node is determined using the following formula. n :

[0019] β1F z ≤αF n ≤β2F z

[0020] Where α is the conversion coefficient between the pressure node torque and the sliding resistance, F z β1 and β2 are the axial force values ​​at the pressure relief node positions under the critical bearing state of the arch frame, and the pressure relief slip safety factors are β1 and β2.

[0021] Furthermore, S4 includes:

[0022] S41: Conduct a series of mechanical tests on the eccentric force of ultra-lightweight pressure-relief arch frame components, determine the load-bearing strength envelope of the ultra-lightweight pressure-relief arch frame through data fitting, and determine the load-bearing strength criterion of the arch frame in combination with the load-bearing strength envelope;

[0023] The expression for the load-bearing strength envelope is as follows:

[0024] F(N / N u M / M u )=1

[0025] Where N and M are the axial force and bending moment of the ultra-lightweight pressure-relief arch frame section, respectively. u With M u These represent the ultimate axial compressive bearing capacity and ultimate bending bearing capacity of the ultralight compression arch frame, respectively, F(N / N).u M / M u ) is a function expression with N and M as variables, representing the load-bearing strength envelope.

[0026] Furthermore, S4 also includes:

[0027] S42: Find the key stress location of the arch frame by the internal force distribution characteristics, determine the ultimate bearing state of the key stress location of the arch frame by the bearing strength criterion, and combine the bearing strength criterion to determine the value of the external load acting on the arch frame when the critical bearing state is reached;

[0028] The expression for the bearing capacity criterion is as follows:

[0029] Stable load-bearing state: F(N / N) u M / M u ) < 1

[0030] Instability and failure state: F(N / N) u M / M u )≥1.

[0031] Furthermore, S5 includes:

[0032] Calculate the comprehensive evaluation index of the support under different design parameters, and determine the optimal design parameters of the ultra-lightweight pressure relief arch frame through the optimal comprehensive evaluation index of the support.

[0033] The expression for the comprehensive evaluation index of the support is shown in the following formula:

[0034] U=γ1[F u / (E)]+ γ2[F u / (LSρ)]

[0035] Where U is the comprehensive evaluation index of support, γ1 and γ2 are the weighting coefficients of the evaluation index, and F u Where E is the ultimate bearing capacity, L is the material cost of the arch frame, S is the perimeter of the arch frame, and ρ is the density of the arch frame.

[0036] The present invention has the following beneficial effects:

[0037] Compared with commonly used arch frames on site, the ultra-lightweight pressure-relief arch frame of this invention has the advantages of simple manufacturing process, strong load-bearing capacity, light weight, and high construction efficiency. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the ultralight pressure relief arch frame of the present invention.

[0039] Figure 2 This is a schematic diagram of the ultralight pressure relief arch frame design method of the present invention. Detailed Implementation

[0040] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0041] This invention provides an ultralight pressure-relief arch frame 1, such as... Figure 1 As shown, the ultra-lightweight pressure-yielding arch frame 1 is composed of multiple overlapping segments, forming an overall arched structure. Each segment is made of lightweight, high-performance steel through an integrated bending process. The overlapping nodes of the ultra-lightweight pressure-yielding arch frame 1 are connected and fixed by cable clamping components 3, forming pressure-yielding nodes 2 that enable pressure-yielding sliding. Compared with commonly used arch frames on site, the ultra-lightweight pressure-yielding arch frame of this invention has the advantages of simple manufacturing process, strong load-bearing capacity, light weight, and high construction efficiency.

[0042] This invention also provides a design method for an ultra-lightweight pressure-yielding arch frame, particularly a pressure-yielding type ultra-lightweight pressure-yielding arch frame support design method suitable for complex geological conditions such as mine roadways and tunnels. Figure 2 As shown, the method includes:

[0043] S1: Based on the on-site engineering geological conditions, obtain the cross-sectional parameters of the chamber, the distribution of ground stress and the mechanical properties of the surrounding rock, establish a geomechanical simulation model, and determine the design value of the arch frame bearing capacity.

[0044] S2: Taking the ultra-lightweight pressure-yielding arch frame as the design object, based on the underground engineering geological conditions and design parameters, a mechanical calculation model of the ultra-lightweight pressure-yielding arch frame is established, the internal force calculation formula of the ultra-lightweight pressure-yielding arch frame is derived, and the internal force distribution characteristics are clarified.

[0045] In one implementation, the mechanical calculation model includes an external load distribution model and an arch frame structural mechanical model. The internal force calculation formula for the arch frame is derived from this model to obtain the internal force distribution characteristics of the arch frame cross-section. Specifically: first, the structural form, loads, and constraints are assumed; then, the force method is used to derive the internal forces of a statically indeterminate arch frame, establish the basic system, calculate the displacement coefficient, solve for redundant unknown forces, derive the internal force calculation formula for any cross-section, and obtain the internal force distribution characteristics of the arch frame.

[0046] S3: Based on the internal force distribution characteristics, design the node parameters of the ultra-lightweight pressure relief arch frame, arrange pressure relief nodes at key slip points where the bending moment is less than the set threshold, and design the number, location and torque of the pressure relief nodes.

[0047] In implementation, the location of nodes needs to match the key areas of internal forces and geometric stress characteristics. Pressure relief nodes should be designed at locations with small bending moments, large axial forces, and changes in the direction of bending moments. The number of nodes is based on the cross-sectional dimensions of the chamber and the number of arch sections. The design of node torque is based on the bending moment and axial force at the node and the strength limit of the arch material.

[0048] As an optional implementation, the torque F of the relief node is determined by the following formula. n :

[0049] β1F z ≤αF n ≤β2F z

[0050] Where α is the conversion coefficient between the pressure node torque and the sliding resistance, F z β1 and β2 are the axial force values ​​at the pressure relief node positions under the critical bearing state of the arch frame, and the pressure relief slip safety factors are β1 and β2.

[0051] S4: Conduct eccentric pressure mechanical tests on ultra-lightweight pressure-yielding arch frame components, determine the load-bearing strength criterion, calculate the ultimate load-bearing capacity of ultra-lightweight pressure-yielding arch frames under different selection conditions, and clarify the critical load-bearing state of ultra-lightweight pressure-yielding arch frames in conjunction with the load-bearing strength criterion.

[0052] In one implementation, S4 includes:

[0053] S41: Conduct a series of eccentric mechanical tests on ultra-lightweight pressure-yielding arch frame components, determine the load-bearing strength envelope of the ultra-lightweight pressure-yielding arch frame through data fitting, and determine the load-bearing strength criterion of the arch frame in combination with the load-bearing strength envelope.

[0054] The expression for the load-bearing strength envelope is as follows:

[0055] F(N / N u M / M u )=1

[0056] Where N and M are the axial force and bending moment of the ultra-lightweight pressure-relief arch frame section, respectively. u With M u These represent the ultimate axial compressive bearing capacity and ultimate bending bearing capacity of the ultralight compression arch frame, respectively, F(N / N). u M / M u ) is a function expression with N and M as variables, representing the load-bearing strength envelope.

[0057] S42: Locate the key stress location of the arch frame by the internal force distribution characteristics, and determine the ultimate bearing state at the key stress location of the arch frame by the bearing strength criterion; combine the bearing strength criterion to calculate the ultimate bearing capacity of the ultra-lightweight bearing arch frame under different selection conditions, and the external load value acting on the arch frame when the critical bearing state is reached is the ultimate bearing capacity.

[0058] The expression for the bearing strength criterion is as follows:

[0059] Stable load-bearing state: F(N / N) u M / M u ) < 1

[0060] Instability and failure state: F(N / N) u M / M u )≥1.

[0061] S5: Introduce a comprehensive evaluation index for support, and determine the optimal design parameters by comprehensively considering material cost, cross-sectional area and density, while ensuring that the ultimate bearing capacity is higher than the design value.

[0062] This step introduces economic evaluation indicators to perform multi-objective optimization and determine the optimal design parameters. Specifically, it calculates the comprehensive evaluation index of the support under different design parameters, and determines the optimal design parameters of the yielding type ultra-light yielding arch frame based on the optimal comprehensive evaluation index of the support.

[0063] In one implementation, the expression for the comprehensive evaluation index of support is shown below:

[0064] U=γ1[F u / (E)]+ γ2[F u / (LSρ)]

[0065] Where U is the comprehensive evaluation index of support, γ1 and γ2 are the weighting coefficients of the evaluation index, and F u Where E is the ultimate bearing capacity, L is the material cost of the arch frame, S is the perimeter of the arch frame, and ρ is the density of the arch frame.

[0066] After obtaining the optimal design parameters, the design can be verified through numerical calculations, and secondary optimization can be carried out in combination with on-site feedback.

[0067] The ultra-lightweight pressure-yielding arch support design method of the present invention can take into account the high strength, lightweight and deformation coordination of the arch frame, effectively improve the support safety and economy of underground engineering under weak surrounding rock and high ground stress conditions, and make up for the shortcomings of existing designs in terms of deformation coordination and economy.

[0068] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An ultralight pressure-relief arch frame, characterized in that, The ultra-lightweight pressure-relief arch frame is composed of multiple overlapping segments, forming an overall arched structure. Each segment is made of lightweight, high-performance steel through an integrated bending process. The overlapping nodes of the ultra-lightweight pressure-relief arch frame are connected and fixed by a cable clamping assembly, forming pressure-relief nodes that can achieve pressure-relief sliding.

2. A design method for an ultralight pressure-relief arch frame as described in claim 1, characterized in that, The method includes: S1: Based on the on-site engineering geological conditions, obtain the cross-sectional parameters of the chamber, the distribution of ground stress and the mechanical properties of the surrounding rock, establish a geomechanical simulation model, and determine the design value of the arch bearing capacity; S2: Taking the ultra-lightweight pressure-yielding arch frame as the design object, based on the underground engineering geological conditions and design parameters, a mechanical calculation model of the ultra-lightweight pressure-yielding arch frame is established, the internal force calculation formula of the ultra-lightweight pressure-yielding arch frame is derived, and the internal force distribution characteristics are clarified. S3: Based on the internal force distribution characteristics, design the node parameters of the ultra-lightweight pressure relief arch frame, arrange pressure relief nodes at key slip points where the bending moment is less than the set threshold, and design the number, location and torque of the pressure relief nodes; S4: Conduct eccentric pressure mechanical tests on ultra-lightweight pressure-yielding arch frame components, determine the bearing strength criterion, calculate the ultimate bearing capacity of ultra-lightweight pressure-yielding arch frames under different selection conditions, and clarify the critical bearing state of ultra-lightweight pressure-yielding arch frames in conjunction with the bearing strength criterion. S5: Introduce a comprehensive evaluation index for support, and determine the optimal design parameters by comprehensively considering material cost, cross-sectional area and density, while ensuring that the ultimate bearing capacity is higher than the design value.

3. The design method according to claim 2, characterized in that, The mechanical calculation model of the ultralight pressure-relief arch frame includes an external load distribution model and an arch frame structural mechanical model.

4. The design method according to claim 2, characterized in that, The torque F at the relief node is determined by the following formula. n : β1F z ≤αF n ≤β2F z Where α is the conversion coefficient between the pressure node torque and the sliding resistance, F z β1 and β2 are the axial force values ​​at the pressure relief node positions under the critical bearing state of the arch frame, and the pressure relief slip safety factors are β1 and β2.

5. The design method according to claim 4, characterized in that, S4 includes: S41: Conduct a series of mechanical tests on the eccentric force of ultra-lightweight pressure-relief arch frame components, determine the load-bearing strength envelope of the ultra-lightweight pressure-relief arch frame through data fitting, and determine the load-bearing strength criterion of the arch frame in combination with the load-bearing strength envelope; The expression for the load-bearing strength envelope is as follows: F(N / N u , M / M u )=1 Where N and M are the axial force and bending moment of the ultra-lightweight pressure-relief arch frame section, respectively. u With M u These represent the ultimate axial compressive bearing capacity and ultimate bending bearing capacity of the ultralight compression arch frame, respectively, F(N / N). u M / M u ) is a function expression with N and M as variables, representing the load-bearing strength envelope.

6. The design method according to claim 5, characterized in that, S4 further includes: S42: Find the key stress location of the arch frame by the internal force distribution characteristics, determine the ultimate bearing state of the key stress location of the arch frame by the bearing strength criterion, and combine the bearing strength criterion to determine the value of the external load acting on the arch frame when the critical bearing state is reached; The expression for the bearing capacity criterion is as follows: Stable load-bearing state: F(N / N) u M / M u ) < 1 Instability and failure state: F(N / N) u M / M u )≥1.

7. The design method according to any one of claims 2-6, characterized in that, S5 includes: Calculate the comprehensive evaluation index of the support under different design parameters, and determine the optimal design parameters of the ultra-lightweight pressure relief arch frame through the optimal comprehensive evaluation index of the support. The expression for the comprehensive evaluation index of the support is shown in the following formula: U=γ1[F u / (E)]+ γ2[F u / (LSρ)] Where U is the comprehensive evaluation index of support, γ1 and γ2 are the weighting coefficients of the evaluation index, and F u Where E is the ultimate bearing capacity, L is the material cost of the arch frame, S is the perimeter of the arch frame, and ρ is the density of the arch frame.

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