Hollow tubular gradient porous energy-absorbing anchor rod and preparation method thereof
By designing hollow tubular gradient porous energy-absorbing anchors, and optimizing pore distribution using gradient porosity and topological optimization algorithms, the problem of insufficient impact resistance of traditional anchors is solved, and efficient shock absorption and stable rock mass support is achieved.
Patent Information
- Application Number
- CN202510619605.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-14
- Publication Date
- 2025-07-11
AI Technical Summary
When facing impact loads, traditional anchors have insufficient impact resistance and cannot effectively absorb impact energy, resulting in anchor fracture and rock mass instability.
A hollow tubular gradient porous energy-absorbing anchor is designed, and non-transmitted depression pores are set on the outer and inner anchor walls. The porosity increases from the anchor section to the free section according to the gradient, and the porosity distribution is optimized through topological optimization algorithms. The pores in the inner layer are connected to disperse the impact energy.
It improves the absorption effect of anchor rods on impact energy, avoids local stress concentration, ensures the bonding strength and bearing capacity between anchor rods and rock mass, and is suitable for geotechnical engineering support under complex geological conditions.
Smart Images
Figure CN120291912A_ABST
Abstract
Description
Technical Field
[0001] The present invention mainly relates to the technical field of geotechnical engineering support, and particularly relates to a hollow tubular gradient porous energy-absorbing anchor rod and a preparation method thereof. Background Art
[0002] In the field of geotechnical engineering support, traditional anchor rod support is widely used. Traditional anchor rods mainly transfer tensile force to the interior of the rock mass through the bonding action between themselves and the rock mass, thereby playing a role in strengthening and supporting the rock mass. Its working principle is to utilize the friction and bonding force between the anchorage section of the anchor rod and the rock mass to limit the displacement and deformation of the rock mass and improve the stability of the rock mass.
[0003] However, traditional anchor rods have obvious deficiencies in anti-impact ability when facing impact loads. When subjected to impact effects such as rock bursts, earthquakes, blasting vibrations, or sudden rock falls, traditional anchor rods cannot effectively absorb impact energy, easily leading to problems such as anchor rod fracture and rock mass instability. In the prior art, although some anchor rods have been improved in structure, such as thickening the diameter of the anchor rod and increasing the length of the anchor rod, these methods have limited effects on improving the anti-impact ability of the anchor rod, and increase the material cost and construction difficulty.
[0004] Currently, some studies have tried to introduce porous structures into anchor rods to improve the energy absorption performance, mainly including two types: uniform porous and random porous. Uniform porous anchor rods are provided with pores of the same size and uniform distribution throughout the rod body, and the energy is absorbed through the deformation of the pores. However, the distribution differences of impact energy in different parts of the anchor rod are not considered, resulting in some pores being unable to fully play their roles, and the overall energy absorption effect being limited. Random porous anchor rods have irregular pore distributions, lack a scientific design basis, are difficult to stably and efficiently absorb impact energy, and have large discreteness in the mechanical properties of the anchor rod, and the effect in actual engineering applications is not good. Summary of the Invention
[0005] The technical problem to be solved by the present invention is: to provide a hollow tubular gradient porous energy-absorbing anchor rod and a preparation method thereof, aiming to improve the absorption effect of impact energy during the anchor rod support process.
[0006] The technical solution adopted by the present invention to solve the above technical problems:
[0007] On the one hand, the present invention provides a hollow tubular gradient porous energy-absorbing anchor rod, which includes an outer anchor rod wall and an inner anchor rod wall. There is a hollow structure between the outer anchor rod wall and the inner anchor rod wall. Depressed pores that do not penetrate the anchor rod wall are provided on both the outer and inner anchor rod walls, and the change rate of the porosity gradually increases in a gradient from the anchorage section to the free section. The porosity is the ratio of the pore area to the area of the anchor rod wall.
[0008] Furthermore, the pores on the inner anchor rod wall are interconnected within a set porosity.
[0009] Furthermore, closed end caps are provided at both ends of the anchor bolt.
[0010] Furthermore, the pores are circular, elliptical or irregular in shape.
[0011] Furthermore, the porosity of the outer anchor bolt wall is less than that of the inner anchor bolt wall.
[0012] On the other hand, the present invention also provides a method for manufacturing a hollow tubular gradient porous energy-absorbing anchor bolt for the above-mentioned hollow tubular gradient porous energy-absorbing anchor bolt, and the method includes:
[0013] The inner anchor bolt wall and the outer anchor bolt wall are respectively divided into a plurality of units along the length direction, and an initial porosity is set for each unit;
[0014] According to the set load conditions, combined with the mechanical property parameters of the material of the inner anchor bolt wall or the outer anchor bolt wall, calculate the impact energy absorbed by each unit at the current porosity, and adjust the porosity of each unit based on the topology optimization algorithm until the impact energy absorbed by each unit meets the set requirements.
[0015] Further, the calculation method of the impact energy absorbed under the previous porosity is: E t = E e + E p , where E t is the total impact energy absorbed by the anchor bolt of the corresponding unit, E e is the elastic deformation energy of the corresponding unit of the anchor bolt, and E p is the plastic deformation energy of the corresponding unit of the anchor bolt.
[0016] Further, the method for determining the initial porosity is: use a linear function or an exponential function to determine the initial porosity of each unit; when using a linear function to determine the initial porosity, the porosity of the Xth unit is where is the porosity of the starting unit of the anchorage section, is the porosity change amount between the Xth unit and the starting unit of the anchorage section, and L is the length of the anchor bolt.
[0017] Further, the adjustment of the porosity of each unit based on the topology optimization algorithm includes: when the impact energy absorbed by a certain unit is lower than the average value of the impact energy absorbed by each unit in the corresponding layer, increase the porosity of the unit; if the impact energy absorbed by a certain unit is higher than the average value of the impact energy absorbed by each unit, reduce the porosity of the unit until the change in the impact energy absorbed by the entire anchor bolt in two adjacent iterative optimizations is less than the set convergence threshold.
[0018] Further, the step of dividing the inner and outer anchor rod walls into multiple units along the length direction includes: dividing the anchor rod into multiple equally spaced units according to a set length, or dividing the anchor rod into multiple units in a way that the length decreases from the anchorage section to the free section.
[0019] Advantages of the present invention:
[0020] (1) In the present invention, the porosity of the hollow tubular gradient porous energy-absorbing anchor rod layer increases in a gradient from the anchorage section to the free section. When the impact energy is transmitted to the anchor rod, the larger porosity in the free section can better buffer and absorb part of the impact energy. The pores distributed in a gradient can evenly reduce the transmission of the impact energy to the anchorage section, avoiding local stress concentration and reducing the bearing capacity of the anchor rod. When the impact energy reaches the anchorage section, the lower porosity can ensure sufficient bonding strength and bearing capacity between the anchor rod and the rock mass, playing a better supporting role for the rock mass to meet the support requirements of geotechnical engineering with high stress or complex geological conditions and ensuring the safety of geotechnical engineering under complex stress conditions.
[0021] (2) The porosity of the outer layer of the anchor rod is lower than that of the inner layer, and the inner pores are set to be partially connected, which can more effectively disperse the impact energy through the deformation and interaction of the pores, improving the impact energy absorption effect.
[0022] (3) The preparation method of the hollow tubular gradient porous energy-absorbing anchor rod described in the present invention does not depend on the simulation results of the finite element model, but optimizes the porosity on the anchor rod wall based on the topology optimization principle of the energy equivalence principle, simplifying the process of porosity optimization. Description of the drawings
[0023] Figure 1 Schematic diagram of the hollow tubular gradient porous energy-absorbing anchor rod described in the present invention;
[0024] Figure 2 Schematic diagram of the porosity change from the anchorage section to the free section;
[0025] Figure 3 Flow chart of the preparation method of the hollow tubular gradient porous energy-absorbing anchor rod described in the present invention;
[0026] Figure 4 Process flow chart of the preparation technology of the hollow tubular gradient porous energy-absorbing anchor rod described in the present invention. Detailed implementation manners
[0027] The hollow tubular gradient porous energy-absorbing anchor rod described in the present invention includes an outer layer and an inner layer. There is a hollow structure between the outer layer and the inner layer. Circular, elliptical or irregularly shaped recessed pores that do not penetrate the anchor rod wall are provided on both the outer and inner layers of the anchor rod. As Figure 1 and Figure 2As shown, the porosity on the inner anchor rod wall and the outer anchor rod wall (the porosity is the ratio of the pore area to the area of the outer or inner anchor rod wall) gradually increases in a gradient from the anchorage section to the free section. In the inner layer, since the anchorage section of the anchor rod mainly bears tensile and shear forces, in order to ensure sufficient bonding strength and bearing capacity between the anchor rod and the rock mass, the porosity of the inner anchorage section is set to be relatively low, specifically, between 5% and 15%. As it extends towards the free section, the porosity gradually increases in a gradient. At the position near the hole mouth in the free section, the porosity reaches the maximum, specifically set between 30% and 50%, so that when the impact energy is transmitted to the anchor rod, the larger pores in the free section can first buffer and absorb part of the energy, reducing the energy transmission to the anchorage section and protecting the stability of the anchorage section. In the outer layer of the anchor rod, in order to ensure sufficient bonding strength and bearing capacity between the anchor rod and the rock mass and avoid excessive energy concentration, the porosity is lower than that of the inner layer.
[0028] Preferably, the pores on the inner anchor rod wall are connected within the set porosity range to form a pore network. Under the action of impact load, the impact energy can be effectively dispersed through the interaction of each pore in the pore network.
[0029] As a further preference, end caps are provided at both ends of the anchor rod for closing, which is used to further ensure the stability of the pore structure and the support performance of the anchor rod.
[0030] As Figure 3 and Figure 4 shown, the preparation method of the hollow tubular gradient porous energy-absorbing anchor rod of the present invention is as follows:
[0031] First, determine the geometric dimensions, material mechanical property parameters, impact load condition parameters, etc. of the anchor rod;
[0032] According to the geometric dimensions of the anchor rod, the outer wall and the inner wall of the anchor rod are divided into multiple units from the length direction at a set equal distance or in a way that the length shrinks from the anchorage section to the free section. An initial porosity value is set for each unit, and the initial porosity value gradually increases in a gradient from the anchorage section to the free section.
[0033] In this embodiment, the inner wall and the outer wall of the anchor rod are evenly divided into n axial units from the anchorage section to the free section along the length direction in the way of set equal distance. The length of each unit is L / n (L is the total length of the anchor rod). Assuming the anchor rod is 3m long, the inner wall and the outer wall of the anchor rod are evenly divided into 10 axial units from the anchorage section to the free section along the set length. The length of each unit is 30cm, and they are numbered E1 to E10 in sequence from the anchorage section to the free section. An initial porosity value is set for the E1 to E10 units, and the initial porosity value of the E1 to E10 units gradually increases in a gradient. The initial porosity is set based on a linear function or an exponential function.
[0034] In this embodiment, the initial porosity is set according to a linear function. The porosity of the Xth unit where is the porosity of the starting unit of the anchorage section, is the change in porosity between the Xth unit and the starting unit of the anchorage section, and L is the length of the bolt.
[0035] According to the set impact load condition parameters, combined with the mechanical property parameters of the inner bolt wall or outer bolt wall material, calculate the impact energy absorbed by each unit under the current pore distribution, and adjust the porosity based on the topology optimization algorithm until the impact energy absorbed by each unit meets the set requirements.
[0036] Specifically, the method for calculating the energy absorbed by each unit under the current pore distribution is: E t = E e + E p , where E t is the total impact energy absorbed by the bolt of the corresponding unit, E e is the elastic deformation energy of the corresponding unit of the bolt, and E p is the plastic deformation energy of the corresponding unit of the bolt. The elastic deformation energy E e is calculated by Hooke's law where σ is the stress and ε is the strain. The plastic deformation energy where σ p is the plastic stress and ε p is the plastic strain.
[0037] The porosity adjustment method is as follows: when the impact energy absorbed by a certain unit is lower than the average value of the impact energy absorbed by each unit of the inner or outer layer of the bolt, increase the porosity of the unit by increasing the area of a single pore or the number of pores; if the impact energy absorbed by a certain unit is higher than the average value of the impact energy absorbed by each unit of the inner or outer layer of the bolt, reduce the porosity of the unit by reducing the area of a single pore or the number of pores, until the change in the impact energy absorbed by the entire bolt is less than the set convergence threshold in two adjacent iterative optimizations, then it is considered that the optimization process converges.
[0038] The sunken pore structure can be manufactured by mechanical processing, such as drilling, milling, etc. If high precision requirements are imposed on the pore structure, metal 3D printing, such as SLM or EBM technology, etc., can also be used for manufacturing.
[0039] Post-process the formed bolt, including heat treatment and anti-corrosion treatment, etc. Eliminate internal stress through heat treatment to improve the comprehensive mechanical properties of the bolt, and perform anti-corrosion treatment on the bolt surface by spraying or galvanizing, etc., to extend the service life of the bolt.
[0040] After post-processing, impact tests, tensile tests, etc. are carried out on the anchor bolts to verify whether the strength, energy absorption performance and pore distribution of the anchor bolts meet the design requirements.
Claims
1. A hollow tubular gradient porous energy-absorbing bolt, characterized in that, The anchor rod includes an outer anchor rod wall and an inner anchor rod wall. There is a hollow structure between the outer anchor rod wall and the inner anchor rod wall. Depressed pores that do not penetrate the anchor rod wall are provided on both the outer and inner anchor rod walls. The change rate of the porosity gradually increases in a gradient from the anchorage section to the free section. The porosity is the ratio of the pore area to the area of the anchor rod wall.
2. The hollow tubular gradient porous energy-absorbing anchor bolt according to claim 1, characterized in that, The pores on the inner anchor rod wall communicate with each other within a set porosity.
3. The hollow tubular gradient porous energy-absorbing anchor rod according to claim 1, wherein Closed end caps are provided at both ends of the anchor rod.
4. The hollow tubular gradient porous energy-absorbing anchor rod according to any one of claims 1-3, characterized in that, The pores are circular, elliptical or irregular in shape.
5. The hollow tubular gradient porous energy-absorbing anchor rod according to any one of claims 1-3, characterized in that, The porosity of the outer anchor rod wall is less than that of the inner anchor rod wall.
6. A preparation method of a hollow tubular gradient porous energy-absorbing anchor rod, which is used to prepare the hollow tubular gradient porous energy-absorbing anchor rod described in any one of claims 1-5, characterized in that, The method includes: Dividing the inner anchor rod wall and the outer anchor rod wall into multiple units along the length direction respectively, and setting an initial porosity for each unit; According to the set load conditions, calculating the impact energy absorbed by each unit at the current porosity in combination with the mechanical property parameters of the material of the inner anchor rod wall or the outer anchor rod wall, and adjusting the porosity of each unit based on the topology optimization algorithm until the impact energy absorbed by each unit meets the set requirements.
7. The preparation method of the hollow tubular gradient porous energy-absorbing anchor rod according to claim 6, characterized in that, The calculation method of the impact energy absorbed at the current porosity is: E t = E e + E p , where E t is the total impact energy absorbed by the corresponding unit bolt, E e is the elastic deformation energy of the corresponding unit of the bolt, and E p is the plastic deformation energy of the corresponding unit of the bolt.
8. The preparation method of the hollow tubular gradient porous energy-absorbing anchor rod according to claim 6, wherein, The initial porosity determination method is as follows: use a linear function or an exponential function to determine the initial porosity of each unit; when using a linear function to determine the initial porosity, the porosity of the Xth unit is where is the porosity of the starting unit of the anchorage section, is the change in porosity between the Xth unit and the starting unit of the anchorage section, and L is the length of the anchor rod.
9. The preparation method of the hollow tubular gradient porous energy-absorbing anchor rod according to claim 6, characterized in that, The adjusting the porosity of each unit based on the topology optimization algorithm includes: when the impact energy absorbed by a certain unit is lower than the average impact energy absorbed by each unit in the corresponding layer, increasing the porosity of that unit; if the impact energy absorbed by a certain unit is higher than the average impact energy absorbed by each unit, reducing the porosity of that unit until the change in the impact energy absorbed by the entire anchor rod in two adjacent iterative optimizations is less than the set convergence threshold.
10. The preparation method of the hollow tubular gradient porous energy-absorbing bolt according to claim 6, characterized in that, The dividing the inner anchor rod wall and the outer anchor rod wall into multiple units along the length direction respectively includes: dividing the anchor rod into multiple equally spaced units according to a set length, or dividing the anchor rod into multiple units in a way that the length decreases from the anchorage section to the free section.