High-anchoring-force anchor rod, tunnel and slope supporting structure

Abstract

The utility model relates to an anchor rod with strong anchoring force, which comprises an anchor rod body, a spiral reinforcing steel bar and two groups of connecting reinforcing steel bars, the anchor rod body is located on the central axis of the spiral steel bar, and the two ends of the spiral steel bar are connected with the anchor rod body through a set of connecting steel bars. And the group of connecting steel bars comprises a plurality of connecting steel bars which are uniformly distributed around the circumference of the anchor rod body. The utility model further relates to a tunnel supporting structure and a slope supporting structure. The anchor rod is suitable for rock-soil supporting under complex geological conditions, the drawing resistance is improved by more than 40% compared with that of a traditional anchor rod, and the anchor rod belongs to the technical field of rock-soil engineering supporting.

Description

Technical Field

[0001] This utility model relates to the field of geotechnical engineering support technology, specifically to a strong anchoring force anchor rod, a tunnel support structure, and a slope support structure. Background Technology

[0002] Traditional anchor bolts often use straight bars or simple threaded structures, which have problems such as insufficient anchoring force and poor bonding performance with soil and rock.

[0003] In existing technologies, anchoring force is improved by increasing the surface roughness of the anchor bolt or by adding additional structures. However, such designs are prone to stress concentration and slippage or fracture under complex geological conditions. In addition, anchor bolts with welded additional structures often affect overall stability due to insufficient bonding strength or uneven distribution.

[0004] CN111472571 A discloses a method for reinforcing soil archaeological sites with anchor bolts and their application, which includes an interlocking platform to prevent the anchor bolt from being pulled out and to increase its interlocking effect with the grout. While this annular additional structure increases the contact area, its discrete ring spacing leads to discontinuous stress transmission and the formation of localized stress peaks.

[0005] Therefore, there is an urgent need for an anchor structure that combines high anchoring force, uniform stress distribution, and reliable welding strength. Utility Model Content

[0006] In view of the technical problems existing in the prior art, the purpose of this utility model is to provide a strong anchoring anchor with strong anchoring force and stable structure.

[0007] Another objective of this utility model is to provide a tunnel support structure.

[0008] Another objective of this utility model is to provide a slope support structure.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A high-anchoring anchor bolt includes an anchor bolt body, a spiral steel bar, and two sets of connecting steel bars. The anchor bolt body is located on the central axis of the spiral steel bar, and both ends of the spiral steel bar are connected to the anchor bolt body through a set of connecting steel bars. The set of connecting steel bars includes multiple connecting steel bars evenly distributed around the circumference of the anchor bolt body.

[0011] As a preferred embodiment, the connecting steel bar includes a connecting section and an inclined section formed by bending. The connecting section is parallel to the axial direction of the anchor body and is set close to the outer wall of the anchor body. The end of the inclined section is connected to one end of the spiral steel bar.

[0012] As a preferred option, the connecting steel bars have a smooth surface and a circular cross-section.

[0013] As a preferred embodiment, the connecting section and the anchor body are connected by welding, and the inclined section and the spiral steel bar are connected by welding.

[0014] As a preferred option, carbon dioxide gas shielded welding is used for welding, and the tensile strength of the weld is ≥400MPa.

[0015] As a preferred option, the spiral steel bar is in the shape of a cylindrical spiral and is formed by twisting plain round steel bars.

[0016] As a preferred embodiment, a set of connecting reinforcing bars includes three connecting reinforcing bars, which are evenly distributed around the anchor body at 120°. The length of the connecting section of the connecting reinforcing bars is 50 mm, and the length of the weld is 50 mm. The spiral reinforcing bars are in three layers, with an axial length of 50 mm and a pitch of 20 mm. The diameter of both the connecting reinforcing bars and the spiral reinforcing bars is 10 mm.

[0017] As a preferred option, the materials for the anchor bolt body, spiral steel bars, and connecting steel bars are all HRB400 grade threaded steel.

[0018] A tunnel support structure equipped with anchor bolts with high anchoring force.

[0019] A slope protection structure equipped with anchor bolts with high anchoring force.

[0020] This utility model has the following advantages:

[0021] 1. Spiral steel bars not only increase the contact area with the soil and rock, but the continuous structure can also evenly distribute stress and avoid local damage.

[0022] 2. Multiple connecting steel bars form a stable support network, significantly improving tensile strength.

[0023] The 3.50 mm parallel weld ensures weld strength and prevents weld cracking during construction or under stress.

[0024] 4. Simple structure, easy to mass-produce, suitable for rapid installation under complex geological conditions, and easy to construct.

[0025] 5. Suitable for rock and soil support under complex geological conditions, with pull-out resistance increased by more than 40% compared to traditional anchor bolts. Attached Figure Description

[0026] Figure 1 This is a 3D diagram of a high-strength anchor bolt.

[0027] Figure 2 This is a preferred dimension drawing for anchor bolts with strong anchoring force.

[0028] Figure 3 This is a cross-sectional view of a high-strength anchor bolt.

[0029] In the figure, 1-anchor rod body, 2-spiral steel bar, 3-connecting steel bar, 31-connecting section, 32-inclined section. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments.

[0031] Example 1

[0032] A high-anchoring anchor bolt includes an anchor bolt body, a spiral steel bar, and two sets of connecting steel bars. The anchor bolt body is located on the central axis of the spiral steel bar, and both ends of the spiral steel bar are connected to the anchor bolt body through a set of connecting steel bars. The set of connecting steel bars includes multiple connecting steel bars evenly distributed around the circumference of the anchor bolt body.

[0033] The connecting reinforcement includes a connecting section and an inclined section formed by bending. The connecting section is parallel to the axial direction of the anchor body and is set close to the outer wall of the anchor body. The end of the inclined section is connected to one end of the spiral reinforcement.

[0034] The connecting steel bars have smooth surfaces and circular cross-sections.

[0035] The connecting section and the anchor body are connected by welding, and the inclined section and the spiral steel bar are connected by welding.

[0036] The welding adopts carbon dioxide gas shielded welding, and the tensile strength of the weld is ≥400MPa.

[0037] Spiral steel bars are cylindrical spirals formed by twisting plain round steel bars.

[0038] A set of connecting reinforcing bars includes three connecting reinforcing bars, which are evenly distributed around the anchor body at 120°. The length of the connecting section of the connecting reinforcing bars is 50 mm, and the length of the weld is 50 mm. The spiral reinforcing bars are in three layers, with an axial length of 50 mm and a pitch of 20 mm. The diameter of both the connecting reinforcing bars and the spiral reinforcing bars is 10 mm.

[0039] The anchor bolt body, spiral steel bars, and connecting steel bars are all made of HRB400 grade threaded steel.

[0040] A method for preparing a high-anchoring-force anchor bolt is as follows:

[0041] A 25mm diameter HRB400 grade threaded steel bar was prepared as the anchor bolt body. 10mm diameter plain round steel bars were twisted using specialized equipment to form a three-layer spiral steel bar with an axial length of 50mm and a pitch of 20mm. Six 10mm diameter HRB400 grade plain round steel bars were selected, bent, and then welded in groups of three at 120° angles to the surface of the anchor bolt body. The parallel weld length between each steel bar and the anchor bolt body was 50mm, using CO2 gas shielded welding. After welding, the weld was subjected to ultrasonic testing to ensure the absence of defects such as cracks and porosity.

[0042] The experimental verification results of this embodiment are as follows:

[0043] Comparative tests verified that the anchor rod using three layers of spiral steel bars (axial length 50 mm, pitch 20 mm) had an ultimate pull-out force of 580 kN, while the pull-out force of four layers of spiral steel bars (pitch 15 mm) was only 520 kN due to insufficient soil filling. The standard deviation of the pull-out force for the two sets of 120° evenly distributed connecting steel bars was +5%, significantly lower than the +15% of the four 90° evenly distributed connecting steel bars, demonstrating a more uniform stress distribution. The 50 mm parallel weld specimen showed no cracking under cyclic loading, while the 40 mm weld specimen showed micro-cracks after 1000 cycles. Therefore, this embodiment is the optimal embodiment.

[0044] The anchor bolt structure of this utility model was verified through finite element simulation and experiments. The following conclusions were drawn regarding parameter optimization analysis, connection structure synergy, and material and process matching:

[0045] (1) Parameter optimization analysis: It was found that the three-layer spiral reinforcement achieves the best balance between contact area and stress dispersion efficiency. If the number of layers exceeds three (e.g., four or more), the spacing between adjacent spirals is too small (<15mm), which will lead to insufficient filling of the soil and rock mass and reduce frictional resistance; if the number of layers is less than three, the contact area is insufficient and stress cannot be effectively dispersed. The continuity of the spiral avoids the discrete stress concentration points of the ring structure, and the spiral inclination angle (determined by the axial length of 50 mm) can guide the soil and rock mass to generate axial compressive force, enhancing the anchoring effect. The outer diameter of the spiral is 3.2 times the diameter of the anchor body, ensuring that the spiral depth can be embedded in the soil and rock mass, while avoiding excessive protrusion that would increase the installation resistance. Although a spiral structure with too many layers can increase frictional resistance, it will lead to material redundancy, a surge in construction difficulty, and may weaken the overall strength due to interlayer interference.

[0046] (2) Coordination of the connection structure: Two sets of connecting steel bars are evenly distributed at 120° to form a symmetrical support network, covering the 360° circumferential force direction of the anchor rod, and forming a spatial synergy with the three layers of spiral steel bars. Experiments show that this layout can improve the uniformity of tensile force distribution by 30%, avoiding the eccentric load fracture caused by traditional asymmetrical welding. The preferred value for the parallel weld length of each connecting steel bar is 50mm: if the weld is too short (<40mm), the welding strength is insufficient; if the weld is too long (>60mm), the heat-affected zone expands, which easily leads to a decrease in the strength of the base material.

[0047] (3) Material and process compatibility: The high yield strength of HRB400 grade rebar combined with the surface properties of plain round steel bars ensures the mechanical compatibility between the anchor bolt body and the additional structure. The selection of carbon dioxide gas shielded welding process ensures that the tensile strength of the weld is stable at ≥400MPa, and ultrasonic testing ensures that there are no defects, overcoming the risk of heat marks in traditional arc welding.

[0048] Example 2

[0049] A tunnel support structure is equipped with a high-anchoring anchor bolt as described in Embodiment 1.

[0050] The implementation process is as follows:

[0051] (1) Drill holes in the rock mass to the designed depth.

[0052] (2) Insert the anchor rod into the hole and inject cement grout to fill the gap.

[0053] (3) After the grout has solidified, install the pad and apply prestress to the design value.

[0054] The parts not mentioned in this embodiment are the same as in Embodiment 1.

[0055] Example 3

[0056] A slope protection structure is equipped with a high-anchorage anchor bolt as described in Embodiment 1.

[0057] The implementation process is as follows:

[0058] (1) Drill holes in the rock mass to the designed depth.

[0059] (2) Insert the anchor rod into the hole and inject cement grout to fill the gap.

[0060] (3) After the grout has solidified, install the pad and apply prestress to the design value.

[0061] The parts not mentioned in this embodiment are the same as in Embodiment 1.

[0062] The above embodiments are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present utility model shall be considered equivalent substitutions and shall be included within the protection scope of the present utility model.

Claims

1. A high holding power anchor, comprising an anchor body, characterised in that: The anchor rod further comprises a spiral reinforcing bar and two groups of connecting reinforcing bars; the anchor rod body is located at the central axis of the spiral reinforcing bar, and the two ends of the spiral reinforcing bar are connected with the anchor rod body through one group of connecting reinforcing bars; the one group of connecting reinforcing bars comprises a plurality of connecting reinforcing bars which are distributed around the circumference of the anchor rod body.

2. A high holding force anchor according to claim 1, characterised in that: The connecting reinforcing bar comprises a connecting section and an inclined section formed by bending; the connecting section is parallel to the axial direction of the anchor rod body and is arranged close to the outer wall of the anchor rod body; and the end of the inclined section is connected with one end of the spiral reinforcing bar.

3. A high holding force anchor according to claim 2, wherein: The connecting reinforcing bar is smooth in surface and circular in cross section.

4. A high holding force anchor according to claim 3, wherein: The connecting section and the anchor rod body are connected through welding, and the inclined section and the spiral reinforcing bar are connected through welding.

5. A high holding force anchor according to claim 4, wherein: The welding adopts carbon dioxide gas shielded welding, and the tensile strength of the welding seam is greater than or equal to 400 MPa.

6. A high holding force anchor as claimed in claim 4, wherein: The spiral reinforcing bar is in the shape of a cylindrical spiral line and is formed by twisting a smooth round reinforcing bar.

7. A high holding force anchor according to claim 6, characterised in that: The one group of connecting reinforcing bars comprises three connecting reinforcing bars which are distributed around the anchor rod body at an angle of 120°; the length of the connecting section of the connecting reinforcing bar is 50 mm, and the length of the welding seam is 50 mm; the spiral reinforcing bar has three layers, the axial length is 50 mm, and the pitch is 20 mm; and the diameter of the connecting reinforcing bar and the spiral reinforcing bar is 10 mm.

8. A high holding power anchor according to claim 1, characterized in that: The materials of the anchor rod body, the spiral reinforcing bar and the connecting reinforcing bar are all HRB400 grade threaded steel.

9. A tunnel support structure characterized by: The anchor rod with high anchoring force.

10. A slope support structure, characterized by: The anchor rod with high anchoring force.

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