Novel negative Poisson's ratio anchor rod supporting structure

Abstract

The invention discloses a novel negative Poisson's ratio anchor rod supporting structure which comprises an anchoring head, a connecting steel pipe, a drill rod, a drill rod support, a drill rod connector, an anchor rod steel bar, a steel bar support and a fixed end anchorage device. The anchoring head, the connecting steel pipe, the drill rod, the drill rod bracket and the drill rod joint form a drill rod main body part; the anchor rod reinforcing steel bar, the reinforcing steel bar support and the fixed end anchorage device form an anchoring part. Wherein the reinforcing steel bar support is of a negative Poisson's ratio structure and wraps the anchor rod reinforcing steel bar, the reinforcing steel bar support and the anchor rod reinforcing steel bar are anchored in a soil body together, and when an axial external load acts on the free end of the anchor rod, the anchor rod is subjected to tensile stress and transmits tensile force to the negative Poisson's ratio structure support. When the inward-concave star-shaped structure in the support is subjected to the action of tension, transverse expansion is generated, the auxetic effect occurs, the contact area between the support and the surrounding soil body is increased, soil and the anchor rod are meshed more tightly, and therefore the friction force between the support and the soil body is increased, the pulling resistance of the soil body to the anchor rod is increased, and the anchoring effect is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of cutting slope support, and in particular to a novel negative Poisson's ratio anchor rod support structure. Background Art

[0002] Slope support is an important part of civil engineering, used to prevent geological disasters such as landslides and collapses, while ensuring the safety of infrastructure such as roads and railways. Anchor rods, as an important component of slope support, are used to fix and support slopes to prevent them from sliding or collapsing. Traditional anchor rods usually use reinforced concrete structures or steel structures. Although they have high strength, their elastic modulus is relatively high, resulting in the anchor rods being unable to produce sufficient deformation when subjected to lateral sliding forces, making it difficult to effectively resist the lateral sliding forces of the slope. By utilizing the characteristic of lateral expansion when axially stretched by negative Poisson's ratio materials, anchor rods will expand laterally when subjected to lateral forces, which can effectively fill the gap between the slope and the anchor rod, increase the friction between the anchor rod and the slope, thereby improving the anchor rod's anti-slip ability, inhibiting the sliding and displacement of the slope, improving the support effect, and enhancing the stability of the slope. Summary of the Invention

[0003] In order to better adapt to complex geological conditions, such as karst areas and soft soil layers, and to improve the applicability and reliability of slope support systems, the present invention provides a new type of negative Poisson's ratio anchor support structure. This new type of anchor is covered with a negative Poisson's ratio structural material bracket, so that when the free end of the anchor is subjected to an axial external load (tension), it can expand along the thickness direction, thereby increasing the contact area between the anchor and the slope, and effectively resisting the lateral sliding force from the slope.

[0004] The present invention adopts the following technical solutions:

[0005] A new type of negative Poisson's ratio anchor support structure includes an anchor head, a connecting steel pipe, a drill rod, a drill rod joint, a drill rod support, anchor rod steel bars, a steel bar support, and a fixed end anchor.

[0006] Furthermore, the anchor head is conical, has self-tapping capability, and has an external threaded structure. During the hole-making process, the inner wall of the drilled hole is cut to form an expanded hole in the drilled hole. There is a cavity inside that matches the anchor rod steel bar, and the outside is fixedly connected by a hollow connecting steel pipe whose diameter matches the internal cavity.

[0007] Furthermore, a steel ring is welded on the connecting steel pipe, and a groove matching the smooth end of the drill pipe joint is provided on the steel ring.

[0008] Furthermore, a drill rod bracket is welded to the outside of the drill rod. The supporting cross bar of the drill rod bracket passes through the roller and is connected to the supporting longitudinal bar and the drill rod. Fixed pins are provided on the left and right sides of the roller to prevent the roller from shifting. The drill rod bracket always ensures that the drill rod is in the center of the drill hole. The roller setting facilitates easy exit from the drill hole during grouting.

[0009] Furthermore, one end of the drill rod joint engages with the hollow steel pipe on the anchor head and the other end is connected to the drill rod to form a drill rod body. The drill rod body is fixed on the drilling rig to determine the drilling position and angle, maintain stability, directly drill the soil to form a hole, and place the anchor head at the deepest part of the drill hole.

[0010] Furthermore, the drill rod joint is connected to the drill rod through a thread, and the screwing direction of the drill rod joint is opposite to the rotation direction of the anchor rod.

[0011] Furthermore, the drill pipe is a hollow steel pipe with an inner diameter of 6 cm and a length of 8 m. One end is provided with an external thread connected to the drill pipe joint, and the other end is provided with an internal thread that can be connected to another section of drill pipe and fixed on the drilling rig.

[0012] Furthermore, the anchor rod reinforcement is φ32HRB400 threaded steel bar, and a reinforcement bracket is welded to the outside.

[0013] Furthermore, the steel support is wrapped around the anchor steel bar, with a thickness of 1 cm. The inner core is a special negative Poisson's ratio structure. The core layer cells are interconnected and arranged in an array along the length of the steel bar to form a three-dimensional porous lattice structure.

[0014] Furthermore, the diameter of the anchor rod reinforcement of the outer sleeve support is slightly smaller than the diameter of the drill rod.

[0015] Furthermore, the fixed end anchor includes a fastening nut and an anchor plate. A through hole is provided in the center of the anchor plate. The anchor rod steel bar passes through the through hole and is tightly combined with the fastening nut to achieve pre-tensioning.

[0016] Compared with the existing anchor support structure, the beneficial effects of the present invention are:

[0017] (1) The steel support in the present invention involves a special negative Poisson's ratio structure. When an axial external load acts on the free end of the anchor rod, the anchor rod will be subjected to tensile stress and transmit the tensile force to the negative Poisson's ratio structural support. When the inward-concave star-shaped structure inside the support is subjected to tensile force, it will be displaced. The inward-concave sandwich star-shaped structure will be supported and expanded laterally, resulting in a tensile expansion effect. The engagement between the soil and the anchor rod will be tighter, which will increase the pull-out resistance of the soil to the anchor rod and improve the pull-out resistance and stability of the anchor rod.

[0018] (2) The steel support has a good negative Poisson's ratio effect. When subjected to tension, it produces lateral expansion, which improves the bond between the anchor and the rock or soil and enhances the pull-out resistance. In slope anchor support projects, this negative Poisson's ratio characteristic of the steel support can be more effectively utilized to achieve a good anchoring effect, thereby reducing the demand for materials and construction costs, and also reducing the restrictions of site conditions.

[0019] (3) The drill rod support is set in the form of a roller, which not only supports the drill rod to ensure that the drill rod is in the center of the borehole, but also allows the drill rod to easily exit the borehole by rolling on the roller during grouting. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the anchor support structure.

[0021] Figure 2 Detailed diagram of the components of the anchor support structure.

[0022] Figure 3 Schematic diagram of steel bar support.

[0023] Figure 4 Schematic diagram of the inner core structure of the steel support.

[0024] Figure 5 This is a top view of the anchor support structure.

[0025] Among them: anchor head 1, connecting steel pipe 2, steel ring 21, drill pipe joint 3, drill pipe 4, anchor steel bar 5, steel bar bracket 6, drill pipe bracket 7, supporting longitudinal rod 71, supporting cross bar 72, roller 73, fixing pin 74, fixed end anchor 8, fastening nut 81, anchor plate 82. DETAILED DESCRIPTION

[0026] like Figure 1 As shown, the present invention provides a new type of negative Poisson's ratio anchor support structure. In order to make the purpose and technical solution of the embodiment of the present invention clearer, the device structure of the embodiment of the present invention will be clearly and completely described in combination with the specific structural drawings of the embodiment of the present invention.

[0027] The anchor head 1 is a cone with a diameter of 11 cm, which is provided with a threaded structure. When drilling a hole in the soil, an expansion hole is formed in the hole. The hollow steel pipe 2 with a diameter of 6 cm is welded to the outside. The hollow steel pipe 2 is welded to the outside of the steel ring 2. The steel ring 21 is provided with a slot to engage with the drill pipe joint 3.

[0028] The drill rod 4 is a hollow steel pipe with a diameter of 6 cm. Drill rod supports 7 are welded at regular intervals, with a total of 5 being provided. The anchor head 1 is connected through the drill rod joint 3 to form an anchor rod body.

[0029] The drill rod support 7 is composed of a supporting cross bar 72, a supporting longitudinal bar 71, a roller 73, and a fixing pin 74. The supporting cross bar 72 is 3 cm long, the supporting longitudinal bar 71 is 2.5 cm long, and the roller 73 is a sphere with a through hole in the middle that passes through the supporting cross bar 72. The fixing pin 74 is fixed on both sides of the roller and maintains a certain distance from the roller. The distance from the center of the anchor rod to the bottom of the roller is slightly smaller than the maximum radius of the anchor head (drilling radius), so that the anchor rod is placed just in the center of the drill hole.

[0030] The anchor rod body is fixed to the drilling rig. After the position and angle of the drill hole are determined, the drilling rig is kept stable, started and drilled directly into the soil, and the drill bit is rotated to cut the soil. When the hole reaches the required depth, the anchor head is placed at the deepest part of the hole, and the anchor rod steel bar is inserted into the drill rod body. Grouting is injected into the hole while the drill rod is slowly withdrawn.

[0031] The anchor reinforcement 5 is made of φ32HRB400 threaded steel bar.

[0032] The steel bar support 6 is sheathed around the steel bar. Figure 3 As shown, one is set every 1m along the steel bar, and a total of 6 are set, and the inner core is a negative Poisson's ratio structure, such as Figure 4 As shown, each core layer unit cell is interconnected to form a two-dimensional porous mesh structure. The core layer is arranged in an array every 5 cm along the length direction of the steel bar to form a three-dimensional porous lattice structure. A layer of steel plate is welded on the outside. The diameter of the steel bar bracket is slightly smaller than the drill rod. The bracket is 1 cm thick and plays a supporting role to ensure that the anchor rod steel bar is in the center of the drill hole before grouting.

[0033] The fixed end anchor 8 includes a fastening nut 81 and an anchor plate 82 . The anchor plate is provided with a circular hole matching the diameter of the steel bar. The steel bar passes through the anchor plate 82 and is fixed to the end of the steel bar by the fastening nut 81 .

[0034] The technical solutions provided by this application are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of this application. The description of the above embodiments is only intended to help understand the method and core concept of this application. Those skilled in the art may modify and improve this application, and such modifications and improvements are also included in the scope of protection of the claims of this application.

Claims

1. A new type of negative Poisson's ratio anchor support structure, used for active reinforcement of general cutting slopes, etc., characterized by: include: Anchor head 1, connecting steel pipe 2, drill rod 4, drill rod support 7, drill rod joint 3, anchor rod steel bar 5, steel bar support 6, fixed end anchor 8; the anchor head (drill bit) 1 is provided with a threaded structure on the outside, with a cavity matching the steel bar head inside, and a hollow connecting steel pipe 2 with a diameter adapted to the internal cavity is fixedly connected on the outside; the drill rod 4 is connected to the anchor head 1 through a drill rod joint 3; the drill rod support 7 is welded to one end of the outside of the drill rod; the anchor rod steel bar 5 is covered with a steel bar support 6 and placed inside the drill rod, at the center of the drill hole; the fixed end anchor 8 is fixed to the free end of the steel bar.

2. A new type of negative Poisson's ratio anchor support structure according to claim 1, characterized in that: A steel ring 21 is welded to the connecting steel pipe 2, and a groove is provided on the steel ring to fit with the smooth end of the drill pipe joint.

3. The novel negative Poisson's ratio anchor support structure according to claim 1 is characterized in that: The inner wall of one end of the drill rod joint 3 is provided with a thread and is connected to the drill rod 4, and the smooth round mouth at one end is engaged with the steel ring 21.

4. The novel negative Poisson's ratio anchor support structure according to claim 1 is characterized in that: One end of the drill rod 4 is provided with an external thread connected to the drill rod joint 3, and the other end is provided with an internal thread, and is a hollow steel pipe with a diameter of 6 cm.

5. The novel negative Poisson's ratio anchor support structure according to claim 1 is characterized in that: The drill rod support 7 includes a support cross bar 72, a support longitudinal bar 71, a roller 73, and a fixing pin 74. The support cross bar 72 passes through the roller 73 and is connected to the support longitudinal bar 71. The other end of the support longitudinal bar 71 is connected to the outside of the drill rod. Fixing pins 74 are provided on the left and right sides of the roller 73.

6. The novel negative Poisson's ratio anchor support structure according to claim 1 is characterized by: The anchor reinforcement 5 is φ32HRB400 threaded steel bar.

7. The novel negative Poisson's ratio anchor support structure according to claim 1 is characterized in that: The steel bar supports 6 are arranged every 1m and are arranged along the outer circumference of the steel bar, wrapping the anchor bar, and are a star-shaped negative Poisson's ratio structure.

8. The novel negative Poisson's ratio anchor support structure according to claim 1 is characterized by: The fixed end anchor 8 includes a fastening nut 81 and a P-type anchor plate 82. The P-type anchor plate 82 fixes the end of the steel bar.

9. The novel negative Poisson's ratio anchor support structure according to claim 1, characterized in that: The drilling is done directly through a drilling rig, using the self-tapping ability of the anchor head to squeeze the soil into a hole, without the need for additional soil removal construction steps.

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