Multi-stage anchor net supporting structure and preparation method thereof

Abstract

The invention relates to the field of building structure engineering, in particular to a multistage anchor net supporting structure and a preparation method thereof. The structure comprises: a central anchor; the multi-stage branch structures are radially and uniformly distributed around the central anchoring part, each stage of branch structure comprises a plurality of branch lines and an annular component, the branch lines and the annular components are concentrically arranged, and the central anchoring part is taken as a circle center; the connection points of the previous-stage branch structure and the next-stage branch structure form a multi-stage node, and a specified angle is formed between the branch line in the previous-stage branch structure and the branch line in the next-stage branch structure of the same common-stage node; the multi-stage branch structures are connected through a plurality of multi-stage annular components to form the multi-stage anchor net supporting structure.

Description

Technical Field

[0001] This invention relates to the field of building structural engineering, specifically to a multi-level anchor mesh support structure and its preparation method. Background Technology

[0002] In geotechnical engineering projects such as tunnels, mines, and slopes, anchor mesh support is a commonly used and effective form of support. However, existing anchor mesh structures, such as traditional diamond-shaped steel mesh or welded steel mesh, still have some problems in practical applications: First, the load transfer path is not ideal, easily leading to stress concentration between anchor rods, resulting in high peak internal forces and insufficient utilization of material strength; second, the overall out-of-plane stiffness of the structure is insufficient, resulting in poor adaptability under geological conditions with large deformations; third, the mesh nodes are mostly simple welds or ties, making it difficult to guarantee their connection strength and durability, thus becoming weak links in the structure; finally, traditional anchor meshes have low modularity, and on-site processing and fabrication are complex, resulting in material waste and low support efficiency.

[0003] In nature, the leaves of the Victoria amazonica exhibit exceptional mechanical load-bearing capacity. Its macroscopic structure and microscopic morphology together constitute a highly efficient energy dissipation and load transfer mechanism. The core mechanism of this performance stems from its highly ordered fractal vein structure: the vein system extends radially outward from the petiole attachment point as the mechanical center, constructing a layered network framework through multi-level branches (including midribs, secondary veins, and veinlets). This biomimetic topology can evenly distribute external loads and transfer them step-by-step to the central petiole region, significantly reducing stress concentration effects. This allows for the optimization of structural mechanical properties with extremely low material consumption, demonstrating the typical morphological adaptability of lightweight, high-strength structures under natural selection. Summary of the Invention

[0004] This invention addresses the technical problems in existing anchor meshes, such as high peak internal forces, insufficient out-of-plane stiffness, poor node durability, and inconvenience in conformability and maintenance. It provides a multi-stage anchor mesh support structure.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a multi-level anchor mesh support structure, comprising: a central anchor; and multi-level branch structures radially and uniformly distributed around the central anchor, each branch structure including multiple branch lines and ring-shaped components, the multiple branch lines and ring-shaped components being concentrically arranged with the central anchor as the center; wherein, the connection points between the previous level branch structure and the next level branch structure form multi-level nodes, and the branch lines in the previous level branch structure and the branch lines in the next level branch structure of the same common level node are at a specified angle; the multi-level branch structures are connected via multiple multi-level ring-shaped components to form a multi-level anchor mesh support structure. Beneficial effects

[0006] The multi-stage anchor mesh support structure of this invention efficiently transfers loads to the central anchor through multiple branches, significantly improving the uniformity of stress distribution, fully utilizing material strength, and effectively avoiding localized stress concentration. The structure exhibits strong overall integrity and good deformation coordination, making it particularly suitable for support under complex geological conditions. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of a multi-level anchor mesh support structure according to an embodiment of the present invention.

[0008] Figure 2 This is a schematic diagram of a three-level branch structure in a multi-level anchor net support structure according to an embodiment of the present invention.

[0009] Figure 3 This is a schematic diagram of the branch lines including the centerline in the three-level branch structure of a multi-level anchor net support structure according to an embodiment of the present invention.

[0010] Figure 4 This is a schematic flowchart of a method for preparing a multi-level anchor mesh support structure according to an embodiment of the present invention. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments are described below, with reference to the appendix. Figures 1 to 4 The present invention will be further described in detail below.

[0012] like Figure 1 As shown, the multi-level anchor mesh support structure of the present invention includes a central anchor 1; and a multi-level branch structure (e.g., a three-level branch structure) radially and uniformly distributed around the central anchor 1, with each branch structure including multiple branch lines 2 and annular members 3. Specifically, the multiple branch lines and annular members are concentrically arranged with the central anchor 1 as the center.

[0013] from Figure 1 As can be seen, the connection points between the preceding and following branch structures form multi-level nodes, and the branch lines in the preceding and following branch structures of the same common level node form a specified angle. The multi-level branch structures are connected by multiple multi-level ring-shaped components to form a multi-level anchor mesh support structure.

[0014] Figure 2 This is a schematic diagram of a three-level branch structure in a multi-level anchor net support structure according to an embodiment of the present invention.

[0015] exist Figure 2In the example, the multi-level anchor mesh support structure of the present invention is a three-level anchor mesh support structure, wherein the multi-level branch structure is a three-level branch structure, specifically including a first-level branch structure I, a second-level branch structure II, and a third-level branch structure III, thereby forming a tree-like branch structure. Each level of branch structure includes multiple branch lines (e.g., Figure 1 The system comprises six first-level branch lines, twelve second-level branch lines, and twenty-four third-level branch lines, and at least two annular members, one of which contains multiple common-level nodes.

[0016] Specifically, the first-level branch structure includes multiple first-level branch lines (e.g. Figure 1 The six first-level branch lines and two first-level ring members, both of which are circular members with the central anchor 1 as the center, and the diameter of the first-level ring member closer to the central anchor 1 is smaller than the diameter of the first-level ring member farther from the central anchor 1.

[0017] Furthermore, the second-level branch structure includes three second-level annular members 4, each of which is a circular member centered on the central anchor 1. The diameter of the three second-level annular members 4 gradually increases in the direction away from the center. See details below. Figure 1 .

[0018] Optionally, the specified angle between branch lines in the preceding and following branch structures of the same common-level node is 30° to 60°. For example, the specified angle between the first-level branch line in the first-level branch structure and the second-level branch line in the second-level branch structure is 60°.

[0019] The specific data for the specified angle is calculated and determined by the number of branch lines in the previous level branch structure, the number of branch lines in the next level branch structure, and the level of the current common level node. Optionally, the specified angle between the branch lines in the preceding and following branch structures of the same common level node is 30° to 60°.

[0020] In a branching structure of the same level, the angle between two adjacent branch lines is between 10° and 75°. For example, in a first-level branching structure, the angle between two adjacent first-level branch lines is 60°.

[0021] The included angle between two adjacent branch lines in the same level branch structure, for example, is determined by calculating the number of branch lines in the same level branch structure.

[0022] Optionally, to adapt to the size of falling rocks in actual engineering environments and ensure uniform load distribution, if the number of Class I branch lines is... nThen the angle α between two adjacent branches is 360°. n The number of Level II branches is 2. n The number of Level II branches is 4 n The angle between two adjacent branches is calculated based on the number of branches at each level. α .

[0023] In an optional implementation, when the included angle between two adjacent first-level branch lines is 60°, the common-level node between the first-level branch structure and the second-level branch structure forms a bifurcation angle with the two connected second-level branch lines (e.g., Figure 2 The angle α The angle bisector of the bifurcation angle coincides with the extension of the corresponding first-order branch line, as detailed in [reference needed]. Figure 3 .

[0024] Specifically, the radius ratio of the largest diameter annular member in the first-level branch structure to the largest diameter annular member in the second-level branch structure is 3:5.

[0025] The radius ratio of the largest diameter annular member in the second-level branch structure to the largest diameter annular member in the third-level branch structure is 17:25.

[0026] To ensure that the anchor mesh with the multi-level anchor mesh support structure of this application can effectively curb the falling of gravel in different practical engineering applications, the number of circumferential members (e.g., represented by m) within each level of the anchor mesh branch is calculated based on the size of the falling rocks in actual engineering projects. It should be noted that since the length of the Level I branch line is greater than the lengths of the Level II and Level III branch lines, it is only necessary to ensure that the distance between the two first circumferential members in the Level I branch line is less than the size of the falling rocks. The following expression is used to calculate the number of circumferential members m in the first level, i.e., Level I branch structure: , in, m The number of circumferential components in the first-level branch structure; a The length of the branch line in the first-level branch structure; t This indicates the distance between two adjacent circumferential members of the first-level branch structure, determined based on the minimum rockfall size calculated from engineering geological data in actual engineering practice.

[0027] Optionally, the distance between two adjacent circumferential members of the first-level branch structure t If the value is less than a specific value, the characteristic value is (0.6~0.8). s , sTo determine the minimum representative rockfall size, the potential rockfall size distribution curves from D10 to D15 were obtained through on-site geological logging, joint and fracture statistics, and rock quality index (RQD) analysis. This ensures effective protection for 85% to 90% of potential rockfalls, achieving a good balance between safety and economy.

[0028] Specifically, according to the standard GB 50086 Technical Specification for Rock and Soil Anchors and Shotcrete Support Engineering, the wire mesh size should be 150 mm to 300 mm. For fractured rock masses or severely weathered rock strata, the radial distance between adjacent circumferential members of the first-level branch structure can be increased. t Reduced to 100mm.

[0029] The above expression allows for the precise determination of the branch line length of the first-level branch structure based on the minimum rockfall size in engineering geological data during actual engineering projects. This enables the precise determination of parameters such as the number of levels of the branch structure, the angle between two adjacent branch lines in the first-level branch structure, the number of branch lines in each level of the branch structure, and the number of circumferential components. Consequently, a multi-level anchor mesh support structure adapted to the actual engineering application scenario can be obtained.

[0030] In another alternative implementation, such as Figure 3 As shown, the diameter ratio of the steel wires used in the first-level branch line, the second-level branch line, and the third-level branch line is 4:3:2. The diameters of the first-level branch line, the second-level branch line, and the third-level branch line are the same as the diameters of the circumferential components at each level.

[0031] Specifically, the connection between the branch lines and the circumferential components in each level of the branch structure is a welded connection. The weld is a full-circumference weld, and the weld leg size is not less than 0.8 times the diameter of the component to be welded. The component to be welded is a branch line or a circumferential component in each level of the branch structure.

[0032] Furthermore, the central anchor 1 includes a central anchor rod and a central ring.

[0033] For example, the diameter of the central anchor bolt is slightly smaller than the diameter of the central ring. Its diameter should be determined based on multiple influencing factors such as engineering geological conditions, design anchoring force, and support structure dimensions, with an optimal range of Φ20 mm to Φ32 mm.

[0034] Calculate the diameter of the center anchor bolt used in the project using the following expression: , in, A This indicates the required cross-sectional area of ​​the center anchor rod, in mm. 2 ; K This indicates the safety factor, which is typically between 1.5 and 2.0. N tThis represents the design value of the axial tensile force of the central anchor bolt, i.e., the design anchoring force, in kN. f ptk This represents the standard value of the prestressed tensile strength of the rod material, in MPa.

[0035] The central ring is, for example, a ring structure formed by bending and welding high-strength steel wire, and is welded to the starting end of the first-level branch line of the first-level branch structure.

[0036] All branch structures are made of high-strength steel wire.

[0037] exist Figure 1 In the example, six first-order branch lines are arranged at uniform intervals around the central axis, with an angle of 60° between any two adjacent first-order branch lines.

[0038] Welding is performed at the end of the first-level branch line and at the beginning of the second-level branch line.

[0039] The circumferential member 4 is, for example, a ring structure made of high-strength steel wire bent and welded, which overlaps at the midpoint and end of each level of branch and is welded to form an overall structure of each level of branch structure.

[0040] Preferably, in the welding process, the weld should be full and continuous, achieving full-circumference welding. The weld leg size should not be less than 0.8 times the diameter of the thinnest wire among all branch wires to ensure that the effective load-bearing area of ​​the weld is greater than the cross-sectional area of ​​the wire, so that failure occurs in the base material rather than the weld point, thus achieving an equal-strength connection. After welding, the weld should be treated with rust prevention, and destructive testing or destructive sampling tests should be performed at important nodes to verify that its tensile and shear strengths meet the design requirements.

[0041] The following specific embodiments illustrate the preparation method of the multi-level anchor mesh support structure of the present invention.

[0042] Specifically, the following steps are included: In step S101, construction parameters are determined to construct the central anchor.

[0043] Taking an anchor spacing of 2000mm as an example, with an anchor rod diameter of 20mm and a rockfall size greater than 150mm, the number of circumferential members in each branch structure is calculated to be 2. The diameter of the central ring is 30mm, the distance from the beginning to the end of each branch structure is 2000mm, the diameter of the circumferential member welded at the end of the first-level branch (i.e., the end of the first-level branch) is 824mm, the diameter of the circumferential member welded at the end of the second-level branch (i.e., the end of the second-level branch) is 1374mm, and the diameter of the circumferential member welded at the end of the third-level branch (i.e., the end of the second-level branch) is 2020mm.

[0044] The diameter of the Class I branch wire and the circumferential member wire welded to the midpoint and end of the Class I branch is 8 mm. The diameter of the Class II branch wire and the circumferential member wire welded to the midpoint and end of the Class II branch is 6 mm. The diameter of the Class III branch wire welded to the circumferential member wire at the midpoint and end of the Class III branch is 4 mm.

[0045] Next, in step S102, a central ring and circumferential components are prefabricated using mechanical equipment to form a closed circular structure, i.e., to form a central ring and circumferential components.

[0046] For example, a bending machine is used to prefabricate a central ring and circumferential components. Straight steel bars are bent at a uniform speed to form a prefabricated ring, and then both ends are fully welded to form a closed circular structure, that is, a central ring and circumferential components.

[0047] Next, in step S103, the branches of the first-level branch structure are arranged at uniform intervals around the central axis, such that the included angle between any two adjacent first-level branch lines is a specified angle, and the starting end of each branch line is welded to the central ring. Two first circumferential members are welded to the specified positions of each first branch line and the ends of each first branch line, respectively, to construct the first-level branch structure.

[0048] Specifically, six first-level branch lines (i.e., the first-level branch lines of the first-level branch structure) are evenly spaced around the central axis, such that the interval angle between two adjacent first-level branch lines is 60°. The branch start of each first-level branch line is welded to the central ring, and two first circumferential members are welded to the designated positions of each first-level branch (in this example, the designated positions are the midpoints of each first-level branch) and the branch ends of each first-level branch line to construct the first-level branch structure.

[0049] Next, in step S104, according to the method for forming the first-level branch structure, the branch structures at each level are constructed step by step to complete the preparation of the multi-level anchor net support structure.

[0050] Specifically, the branch ends of the previous level branch line of each level branch structure are welded to the branch beginning of the current level branch line, and the circumferential components of each level are welded to the designated positions and branches of each level branch line to complete the welding connection of the multi-level anchor mesh support structure, thereby completing the preparation of the multi-level anchor mesh support structure.

[0051] For example, the starting end of the second-level branch line of the second-level branch structure is welded to the ending end of the first-level branch line, and also welded to the first circumferential member in the first branch structure that is far from the central ring. Next, multiple second circumferential members in the second-level branch structure are welded to designated positions and the ends of the second branch lines.

[0052] Furthermore, a third-level branch structure will be constructed, and branch structures at each level will be constructed step by step to complete the preparation of a multi-level anchor mesh support structure.

[0053] 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 descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-level anchor mesh support structure, characterized in that, include: Central anchor (1); The multi-level branch structure is radially and uniformly distributed around the central anchor (1). Each level of branch structure includes multiple branch lines (2) and annular components (3), the multiple branch lines and annular components being concentrically arranged with the central anchor (1) as the center; wherein, The connection points between the previous level branch structure and the next level branch structure form multi-level nodes, and the branch lines in the previous level branch structure and the branch lines in the next level branch structure of the same common level node are at a specified angle. The multi-level branch structure is connected by multiple multi-level ring-shaped components to form a multi-level anchor net support structure.

2. The multi-level anchor mesh support structure according to claim 1, characterized in that, include: The multi-level branching structure is a three-level branching structure, including a first-level branching structure, a second-level branching structure, and a third-level branching structure. Each level of branching structure includes multiple branch lines and at least two ring-shaped components, one of which contains multiple common-level nodes. The first-level branch structure includes multiple first-level branch lines and two first-level ring components. The two first-level ring components are circular components with the central anchor (1) as the center, and the diameter of the first-level ring component closer to the central anchor (1) is smaller than the diameter of the first-level ring component farther from the central anchor (1).

3. The multi-stage anchor mesh support structure according to claim 2, characterized in that, include: The second-level branch structure includes three second-level ring components, all of which are circular components with the central anchor (1) as the center. The diameter of the three second-level ring components gradually increases in the direction away from the center.

4. The multi-level anchor mesh support structure according to claim 1, characterized in that, include: Use the following expression to calculate the number of first circumferential members in the first-level branch structure: ， in, m The number of circumferential components in the first-level branch structure; a The length of the branch line in the first-level branch structure; t This indicates the distance between two adjacent circumferential members of the first-level branch structure, determined based on the minimum representative block size derived from engineering geological data in actual engineering projects.

5. The multi-stage anchor mesh support structure according to claim 1, characterized in that, include: The specified angle between the branch lines in the preceding and following branch structures of the same common level node is 30° to 60°. In the same level of branch structure, the included angle between two adjacent branch lines is 10° to 75°.

6. The multi-stage anchor mesh support structure according to claim 1 or 5, characterized in that, include: The specified angle is calculated and determined by the number of branch lines in the previous level branch structure, the number of branch lines in the next level branch structure, and the level of the current common level node.

7. The multi-stage anchor mesh support structure according to claim 2, characterized in that, include: When the included angle between two adjacent first-level branch lines is 60°, the common level node between the first-level branch structure and the second-level branch structure forms a bifurcation angle with the two connected second-level branch lines, and the angle bisector of the bifurcation angle coincides with the extension of the corresponding first-level branch line.

8. The multi-level anchor mesh support structure according to claim 2, characterized in that, include: The radius ratio of the largest diameter annular member in the first-level branch structure to the largest diameter annular member in the second-level branch structure is 3:5; The radius ratio of the largest diameter annular member in the second-level branch structure to the largest diameter annular member in the third-level branch structure is 17:

25.

9. The multi-stage anchor mesh support structure according to claim 2, characterized in that, include: In the branch structure at all levels, the connection between the branch line and the circumferential component is a welded connection. The weld is a full-circumference weld, and the weld leg size is not less than 0.8 times the diameter of the component to be welded. The component to be welded is a branch line or circumferential component in the branch structure at all levels; and / or The diameter ratio of the reinforcing bars used in the first-level branch line, the second-level branch line, and the third-level branch line is 4:3:2; the diameters of the first-level branch line, the second-level branch line, and the third-level branch line are the same as the diameters of the circumferential members at each level.

10. A method for preparing a multi-stage anchor mesh support structure, used to prepare the multi-stage anchor mesh support structure as described in claim 1, characterized in that, include: Determine the construction parameters to construct the center anchor; Mechanical equipment is used to prefabricate the central ring and circumferential components to form a closed circular structure, that is, to form the central ring and circumferential components; The branches of the first-level branch structure are evenly spaced around the central axis, such that the included angle between any two adjacent first-level branch lines is a specified angle, and the starting end of each branch line is welded to the central ring. Two first circumferential members are welded to the specified positions of each first branch line and the ends of each first branch line, respectively, to construct the first-level branch structure. Based on the construction method of the first-level branch structure, the branch structures at each level are constructed step by step to complete the preparation of the multi-level anchor mesh support structure.

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