Non-prestressed hollow anchor rod suitable for mechanical construction

Abstract

The non-prestressed hollow anchor rod comprises a hollow rod body, a nut, a base plate, a stop-grouting plug and an anti-falling cap, the nut, the base plate, the stop-grouting plug and the anti-falling cap are sequentially arranged on the hollow rod body, the anti-falling cap is installed at the head of the hollow rod body, the stop-grouting plug is installed at the front end of the base plate, and an inner hole of the stop-grouting plug is a through hole and is attached to the large diameter of the hollow rod body. An inner hole of the base plate is a through hole, a gap exists between the inner hole of the base plate and the outer surface of the hollow rod body, and the base plate is arranged at the front end of the nut and tightly pressed by the nut so that the base plate can be tightly attached to the rock surface. The non-prestressed hollow anchor rod has the advantages that the weight is light; 2) the process steps are few, the grouting plumpness is good, and the grouting is more uniform; the construction method is simple, and mechanical construction can be achieved in cooperation with an anchor rod trolley.

Description

Technical Field

[0001] This utility model relates to a non-prestressed hollow anchor rod suitable for mechanized construction, which can replace threaded steel anchor rods under non-prestressed support conditions in various fields, and realize mechanized construction of drilling and injection in the entire process on the anchor rod trolley. Background Technology

[0002] Currently, threaded steel anchor bolts are widely used in the support of transportation tunnels, water conservancy and hydropower projects, underground mines, and other fields, accounting for a large market share. Their main disadvantages include: the anchor bolts are solid structures, resulting in a greater weight per meter compared to hollow bolts of the same specifications, leading to higher labor intensity and lower support efficiency; the need to install grouting pipes and venting pipes during construction also contributes to low construction efficiency, and bending of the grouting or venting pipes within the hole can easily lead to incomplete grouting; misalignment of the threaded steel within the hole affects the consistency of the protective layer and anchoring performance; the need to install venting and grouting pipes, and the requirement for wedging the arch support bolts, involves numerous steps and complex operations, making it difficult to rely entirely on equipment. Therefore, their most significant drawback is the difficulty in achieving mechanized construction methods.

[0003] Mechanized construction is an inevitable trend in anchor bolt support. For example, expandable shell type low-prestress hollow anchor bolts, such as "CN220621918U A Type of Expandable Shell Prestressed Hollow Anchor Bolt," have already achieved mechanized construction. However, this type of metal expandable shell anchor bolt is suitable for surrounding rock requiring prestressing. For conditions with good geological conditions where prestressing is not required, the cost of using this type of expandable shell anchor bolt is high. Therefore, expandable shell anchor bolts cannot replace the most widely used threaded steel anchor bolts. There is an urgent need to design a new type of anchor bolt with a cost roughly equivalent to that of threaded steel anchor bolts, but which can be mechanized, to promote the mechanized development of threaded steel anchor bolts. Utility Model Content

[0004] In order to overcome the above-mentioned shortcomings of the prior art, this utility model proposes a non-prestressed hollow anchor rod suitable for mechanized construction.

[0005] The technical solution adopted by this utility model to solve its technical problem is: a non-prestressed hollow anchor rod suitable for mechanized construction, comprising a hollow rod body and a nut, a washer, a grout stopper, and a fall arrestor set sequentially on the hollow rod body, wherein: the fall arrestor is installed at the head of the hollow rod body, the grout stopper is installed at the front end of the washer, the inner hole of the grout stopper is a through hole that fits with the large diameter of the hollow rod body, the large end face of the grout stopper contacts the washer, the inner hole of the washer is a through hole that has a gap with the outer surface of the hollow rod body, the washer is set at the front end of the nut, the nut presses the washer tightly, so that the washer is in close contact with the rock surface.

[0006] Compared with the prior art, the positive effects of this utility model are:

[0007] 1. Compared to threaded steel anchor rods of the same specifications, the non-prestressed hollow anchor rod of this utility model has the following advantages: 1) Lighter weight. The hollow rod body of this utility model undergoes heat treatment, and its load-bearing capacity is comparable to that of threaded steel anchor rods, but it is lighter and easier to transport and construct; 2) Fewer steps and better fullness. Grouting can be performed directly in the inner hole of the hollow rod body without the need to install grouting pipes and vent pipes, improving construction efficiency and avoiding the problem of incomplete grouting caused by bending when the grouting pipe is inserted into the hole; 3) More uniform. The anti-fall cap at the front end and the grout stop plug at the rear end of this utility model can keep the rod body centered in the hole, effectively ensuring the uniformity of the anchor rod protective layer thickness; 4) Mechanization. The construction method is simple, involving only a few simple steps: drilling anchor holes, inserting anchor bolts, and grouting. It is easy to coordinate with an anchor bolt trolley for mechanized construction. The detailed actions of mechanized construction on the anchor bolt trolley are: drilling—grabbing—pushing in—grouting—exiting; 5) Wide applicability: This mechanized construction method is applicable to the geological and working conditions where traditional threaded steel anchor bolts are used. It is also applicable to working conditions where traditional threaded steel anchor bolts are difficult to operate (such as arch roofs); 6) Labor saving: Only one person is needed to operate the equipment for mechanized anchor bolt support construction. When the anchor bolts in the bolt magazine are used up, only the operator needs to refill them; 7) Safer: During mechanized construction, except for the short time when the anchor bolts are loaded into the bolt magazine, the operator is in the anchor bolt trolley, resulting in higher safety.

[0008] 2. Compared to the expansion-shell type low-prestress hollow anchor bolt, the non-prestressed hollow anchor bolt of this utility model has the following advantages: 1) Lower equipment requirements. While achieving mechanized construction, this utility model does not require both the inner and outer shafts of the anchor bolt trolley to rotate, thus lowering equipment requirements (during mechanized installation of the expansion-shell type low-prestress hollow anchor bolt, the inner sleeve is first used to rotate the rod body counterclockwise, causing the expansion shell head to open and the entire anchor bolt to be fixed in the hole; then the nut is rotated, and the nut presses the washer against the rock surface); 2) Lower cost. The cost of the expansion shell anchor head at the front end of the expansion-shell type low-prestress anchor bolt is far higher than the anti-fall cap at the front end of this utility model. Attached Figure Description

[0009] This utility model will be described by way of example and with reference to the accompanying drawings, wherein:

[0010] Figure 1 This is a schematic diagram of the non-prestressed hollow anchor rod of this utility model, suitable for mechanized construction;

[0011] Figure 2 This is a structural schematic diagram of the fall protection helmet of this utility model;

[0012] Figure 3 This is a schematic diagram of the anchor bolt construction method of this utility model.

[0013] The attached diagram includes the following labels: 1. Hollow rod, 2. Nut, 3. Washer plate, 4. Anti-slip plug, 5. Small cone surface, 6. Spring, 7. Anti-slip spring, 8. Detailed Implementation

[0014] A non-prestressed hollow anchor suitable for mechanized construction, such as Figure 1 As shown, it includes: hollow rod body 1, nut 2, washer 3, grout stop plug 4, anti-fall cap 5, etc., wherein:

[0015] The structure of the fall protection helmet 5 is as follows Figure 2 As shown, the device consists of a spring 7 and a fall arrestor 8, forming a cone-shaped structure that is smaller at the top and larger at the bottom. When inserted into the hole, it provides fall protection. The small conical surface 6 at the tip of the fall arrestor 8 can be a circumferential cone or simply a symmetrical, non-closed cone. The fall arrestor 8 extends diagonally downwards from the main body, forming an elastic support leg of a certain length (determined by the anchor hole diameter), thickness, and width. This structure possesses a certain degree of toughness. Before being inserted into the anchor hole, the elastic support leg has a large opening. After insertion, due to its toughness, the elastic support leg contracts, exerting pressure on the hole wall. When the anchor rod falls, it supports or embeds itself into the hole wall, achieving the fall protection effect. There can be two or more elastic support legs in the circumferential direction.

[0016] The small conical surface and elastic support legs of the anti-fall shrapnel can be made by bending elastic steel sheets.

[0017] Spring 7 is a steel spring, and the spring and the anti-fall spring are connected by welding.

[0018] The fall arrestor 5 is installed at the head of the hollow rod 1. The pitch and size of the spring 7 match the threads on the outer surface of the hollow rod 1, allowing it to be screwed in normally without the hollow rod passing through the fall arrestor.

[0019] The grout stopper 4 is installed at the front end of the pad 3. The inner hole of the grout stopper 4 is a through hole that fits the major diameter of the hollow rod body 1. The large end face of the grout stopper 4 is in contact with the pad 3. During grouting, cement mortar leaks out from the gap between the pad 3 and the anchor hole opening.

[0020] After the fall arrestor 5 is placed into the anchor hole, its large end contacts the anchor hole wall, and the head of the hollow rod 1 is in the center of the fall arrestor. Therefore, the head of the hollow rod is centered in the hole. Similarly, the large end of the grout stop plug 4 also contacts the anchor hole wall (to prevent grout leakage). The hollow rod is centered in the grout stop plug. Since the entire hollow rod is straight and the anchor hole is also straight, the hollow rod is centered in the anchor hole.

[0021] The inner hole of the pad 3 is a through hole, with a gap between it and the outer surface of the hollow rod 1. The pad 3 is in contact with the rock surface and is located at the front end of the nut 2. The nut 2 has internal threads, and the nut presses the pad 3 tightly, so that the pad is in close contact with the rock surface. When the cement mortar solidifies, if the surrounding rock tends to displace, the load is borne on the pad, and the pad can limit the displacement of the surrounding rock.

[0022] The working principle of this utility model:

[0023] This invention enables mechanized support for non-prestressed anchor bolts. The principle is as follows: the anti-fall cap consists of a spring and an anti-fall spring plate. The spring has a helical structure that matches the helical structure of the anchor bolt, allowing it to rotate normally to the head of the anchor bolt. When the hollow anchor bolt is pushed into the anchor hole, the anti-fall cap, with its conical structure and small end entering first, and featuring a small conical surface at the front, smoothly enters the anchor hole. When the pad is pressed tightly against the tunnel rock surface and the pad is pressed tightly against the nut, the rod is pushed into place. The anchor rod is a hollow anchor rod. The anchor bolting machine is pressed tightly against the tail of the hollow rod. The anchor bolting machine can directly inject grout into the anchor hole through the inner hole of the anchor rod. After the grouting is completed, when the anchor bolting machine is separated from the rod, the anchor rod tends to fall downwards due to its own weight and the weight of the cement mortar supported on the pad. However, because the large end of the anti-fall cap cone structure is facing downwards and the initial opening size of the two elastic legs is larger than the inner diameter of the anchor hole, the elastic legs exert pressure on the inner wall of the hole. Therefore, the elastic legs of the anti-fall cap can immediately support the inner wall of the hole, thereby preventing the anchor rod and cement mortar from falling, continuously bearing the load and maintaining balance until the cement mortar is completely solidified.

[0024] The anchor bolt trolley for installing hollow anchor bolts, which is compatible with this utility model, has two workstations: a rock drill workstation and an anchor bolt machine workstation. The rock drill workstation is used to drill anchor bolt holes (using a drill bit and drill rod, with the drill rod's tail connected to the rock drill via a threaded structure). After drilling is completed, the rock drill is moved away by rotating or translating, and the anchor bolt machine reaches the original rock drill workstation. The anchor bolt machine has pre-grabbed the anchor bolt in the anchor bolt magazine and clamped it onto the machine. When the anchor bolt machine reaches the original rock drill position, the front end of the anchor bolt is aligned with the hole opening, and the rear end of the anchor bolt is threadedly connected to the anchor bolt machine. The anchor bolt body has external threads, and the anchor bolt machine has a sleeve with internal threads. After the anchor bolt is grabbed and placed on the anchor bolt machine, the sleeve is aligned with the anchor bolt body and screwed on, connecting and mating the anchor bolt machine and the anchor bolt body. Later, cement mortar can be injected into the anchor hole through this sleeve from the inner hole of the anchor bolt.

[0025] The construction method of this utility model for non-prestressed hollow anchor rods:

[0026] 1) The anchor bolt, already equipped with the fall arrestor, grout stopper, nut, and washer, is placed into the anchor bolt magazine; 2) The rock drill on the anchor bolt trolley moves to the cantilever and drills the anchor hole at the designated position until drilling is complete; 3) The rock drill returns to the zero position and the anchor bolt machine is switched. The flipping mechanism grabs the anchor bolt from the anchor bolt magazine and places it into the anchor bolt machine. The anchor bolt machine aligns with the tail of the anchor bolt and pushes the anchor bolt into the anchor hole until the upper surface of the washer is flush with the tunnel rock surface and the lower surface of the washer is flush with the nut; 4) The grouting equipment on the anchor bolt machine injects grout into the anchor hole through the center hole of the anchor bolt until cement grout is observed flowing out; 5) The anchor bolt machine detaches from the anchor bolt, thus completing the construction of one anchor bolt. Figure 3 As shown.

Claims

1. A non-prestressed hollow anchor rod suitable for mechanized construction, characterized in that: The device comprises a hollow rod body, a nut, a pad plate, a plug and a fall-preventing cap, wherein the fall-preventing cap is installed at the head of the hollow rod body, the plug is installed at the front end of the pad plate, the inner hole of the plug is a through hole, the plug is in close contact with the large diameter of the hollow rod body, the large end surface of the plug is in contact with the pad plate, the inner hole of the pad plate is a through hole, there is a gap between the outer surface of the hollow rod body and the pad plate, the pad plate is arranged at the front end of the nut, and the nut presses the pad plate so that the pad plate is tightly attached to the rock surface.

2. A non-prestressed hollow anchor rod suitable for mechanized construction according to claim 1, characterized in that: The fall-preventing cap is welded by a spring and a fall-preventing sheet.

3. A non-prestressed hollow anchor rod suitable for mechanized construction according to claim 2, characterized in that: The spring has a spiral structure, and the pitch and size of the spring are matched with the thread on the outer surface of the hollow rod body.

4. A non-prestressed hollow anchor rod suitable for mechanized construction according to claim 2, characterized in that: The fall-preventing sheet comprises a small taper surface at the top end and an elastic leg at the tail.

5. A non-prestressed hollow anchor rod suitable for mechanized construction according to claim 4, characterized in that: The small taper surface is a circular cone structure in the circumferential direction.

6. A non-prestressed hollow anchor rod suitable for mechanized construction according to claim 4, characterized in that: The small taper surface is a symmetrical non-closed vertebral surface structure.

7. A non-prestressed hollow anchor rod suitable for mechanized construction according to claim 4, characterized in that: The small taper surface and the elastic leg are made by bending an elastic sheet.

8. A non-prestressed hollow anchor rod suitable for mechanized construction according to claim 1, characterized in that: The elastic leg is at least two in the circumferential direction.

9. A non-prestressed hollow anchor rod suitable for mechanized construction according to claim 1, characterized in that: The fall-preventing cap has a vertebral body structure with a small upper part and a large lower part.

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