Displacement recoverable anti-blast anchor

Abstract

The present application provides a kind of displacement recoverable anti-blast anchor rod, including sleeve, rod body, limit plate and spring, the right end of the internal cavity of sleeve is equipped with internal thread, the limit plate is installed at the opening of sleeve right end, limit plate is threadedly connected with the internal thread of sleeve, the middle part of limit plate 7 is equipped with through-hole;The rod body is threaded in the through-hole of limit plate 7, the left end of rod body is fixedly connected with end slider 1, and the end slider is located in the right end inside the internal cavity of sleeve;The middle part of rod body movably sheaths shear slider, and shear slider is located in the internal cavity of sleeve 5 and is located at the left end outside of internal thread, the outer diameter of shear slider is greater than the inner diameter of internal thread;The spring is sheathed on the rod body, and the spring is located between end slider and shear slider;The right end of the rod body is free section.The present application can realize the toughness recovery of deformation, has the energy-absorbing function of buffer, can improve the anti-blast ability of underground lining structure on anchoring structure.

Description

Technical Field

[0001] This invention relates to the field of blast-resistant support technology for surrounding rock in subway tunnels, specifically a displacement-recoverable blast-resistant anchor bolt. Background Technology

[0002] Because the blast wave propagates within the strata and is influenced by the strata and supporting structures, the propagation pattern of the resulting air shock wave differs from that in free atmosphere. When the shock wave encounters the underground lining structure, it is reflected and superimposed, resulting in an overpressure peak far exceeding the pressure in a free field. To enhance the blast resistance of underground lining structures, a common method is to increase the stiffness and thickness of the underground lining structure to improve structural rigidity and resist the impact of the blast wave. However, this method is costly to construct, and the improvement in blast resistance does not take into account the anchoring structure. Therefore, simply increasing the stiffness and thickness of the underground lining structure to improve its blast resistance is not the best approach. The most economical method to improve the blast resistance of underground lining structures is to use flexible, yielding support structures. This allows the blast load energy to be released and absorbed through structural deformation, and then the remaining blast load is resisted by the rigid structure. Therefore, an improvement scheme addressing the shortcomings of existing technologies is needed. Summary of the Invention

[0003] In response to the problems pointed out in the background art, the purpose of this invention is to propose a displacement-recoverable blast-resistant anchor bolt. By improving the anchor bolt structure, which is the most critical part of the anchoring structure, the anchor bolt is made to have flexible resistance. Under the action of explosive load, it can not only efficiently dissipate energy, but also rebound stably under the action of elastic elements, thereby improving the blast resistance of underground lining structures in the anchoring structure.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A displacement-recoverable explosion-proof anchor bolt includes a sleeve, a rod body, a limiting plate, and a spring. The sleeve is a straight circular metal tube structure closed at the left end, with an internal thread at the right end of its internal cavity. The inner diameter of the internal thread is smaller than the inner diameter of the cavity. The limiting plate is installed at the opening at the right end of the sleeve and is threadedly connected to the internal thread of the sleeve. A through hole is provided in the middle of the limiting plate. The rod body passes through the through hole of the limiting plate, and an end slider is fixedly connected to the left end of the rod body. The end slider is located at the right end of the sleeve cavity. A shear slider is movably sleeved in the middle of the rod body. The shear slider is located inside the sleeve cavity and outside the left end of the internal thread. The outer diameter of the shear slider is larger than the inner diameter of the internal thread. The spring is sleeved on the rod body and is located between the end slider and the shear slider. The right end of the rod body is a free section.

[0005] The right end of the rod is provided with a washer and a nut. The washer is sleeved on the rod, and the nut is threaded to the right end of the rod. The washer and nut are used to apply prestress to the rod.

[0006] The end slider is made of 40Cr steel and its outer diameter is larger than that of the spring.

[0007] The spring is a mold compression spring, and its material is SWOSC_V alloy steel.

[0008] The shearing slider is made of 40Cr steel, and the thickness of the shearing slider is greater than twice the pitch of the internal thread.

[0009] The sleeve has multiple steel bars symmetrically welded on both sides of its outer wall to increase the anchoring force between the anchor bolt anchoring section and the surrounding rock.

[0010] The sleeve includes a cylinder and a plug, with the plug threaded to the left end of the cylinder.

[0011] The principle of this invention: Under explosive load, the underground lining structure is impacted, and the pad plate stretches along with the underground lining structure. The pad plate drives the end slider to move through the rod. The end slider first compresses the mold spring inside the sleeve. When the mold spring reaches its compression limit, it squeezes the shear slider, which shears the internal thread. The internal thread prevents the shear slider from sliding towards the free section. The overall working process of the anchor bolt is divided into three stages: the linear elastic motion stage and the displacement recovery stage. The working stage that the displacement-recoverable anchor bolt can reach is determined by the magnitude of the explosive load acting on the pad plate by the underground lining structure.

[0012] In practical use, the free section of this invention is fixed to the outside of the rock mass or the underground lining structure through a pad plate. The anchored section, anchored in the surrounding rock mass, has a displacement-recoverable elastic damping structure and a plastic deformation structure that improves the support capacity. This allows the displacement of the anchored section to recover after a short period of time following an explosive impact load. Compared with ordinary anchor bolts, the displacement-recoverable blast-resistant anchor bolt can efficiently dissipate energy under explosive loads and can also rebound stably under the action of elastic elements. It has strong flexibility and resistance, and can significantly improve the blast resistance performance of underground lining structures.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. The displacement-recoverable blast-resistant anchor rod is connected to the underground lining structure or the outside of the rock mass through a pad. Under the action of explosive load, the deformation of the underground lining structure or rock mass is transmitted to the mold compression spring inside the sleeve through the rod, which can realize the toughness recovery of the deformation and has the function of buffering and absorbing energy. On-site construction can increase or decrease the number of displacement-recoverable blast-resistant anchor rods according to actual needs, so that the support of the underground lining structure meets the predetermined blast resistance level.

[0014] 2. The displacement-recoverable explosion-proof anchor bolt is designed as an assemblable structure. The end slider, mold compression spring, shear slider, rod body, and limiting plate are all detachable components, allowing for flexible on-site assembly to meet different resistance levels required during field assembly. Furthermore, all components are reusable, effectively saving research time and economic costs. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the segmentation of the anchor bolt; Figure 3 Here are cross-sectional views of the sleeve, rod, and spring; Figure 4 Cross-sectional views of the sleeve, rod, and internal thread; Figure 5 A diagram illustrating the blast-resistant reinforcement of underground lining structures; Figure 6 The figure shows the test results of static load pull-out force when the load is less than the spring's ultimate pressure. Figure 7 The figure shows the test results of static load pull-out force when the load is greater than the spring's ultimate compression but less than the internal thread's ultimate shear strength. Figure 8 The figure shows the static load pull-out force test results when the load is greater than the ultimate shear strength of the internal thread but the force is not transmitted to the limiting plate. Figure 9 The figure shows the static load pull-out force test results when the load exceeds the ultimate shear strength of the internal thread and the force is fully transmitted to the limiting plate.

[0016] In the diagram: 1-End slider, 2-Spring, 3-Shear slider, 4-Internal thread, 5-Sleeve, 6-Rod, 7-Limiting plate, 8-Pad, 9-Nut, 10-Rebar end, 11-Underground lining structure. Detailed Implementation

[0017] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figure 1-4As shown, this invention proposes a displacement-recoverable explosion-proof anchor bolt, comprising a sleeve 5, a rod body 6, a limiting plate 7, and a spring 2. The sleeve 5 is an integral metal straight circular tube structure closed at the left end, with an internal thread 4 at the right end of its internal cavity. The inner diameter of the internal thread 4 is smaller than the inner diameter of the cavity. The limiting plate 7 is installed at the right end opening of the sleeve 5 and is threadedly connected to the internal thread of the sleeve 5. A through hole is provided in the middle of the limiting plate 7. The rod body 6 passes through the through hole of the limiting plate 7, and the left end of the rod body 6 is fixed. An end slider 1 is connected, located at the right end inside the cavity of the sleeve 5; a shearing slider 3 is movably sleeved in the middle of the rod 6, located inside the cavity of the sleeve 5 and outside the left end of the internal thread 4, with the outer diameter of the shearing slider 3 being larger than the inner diameter of the internal thread 4; a spring 2 is sleeved on the rod 6, located between the end slider 1 and the shearing slider 3; the right end of the rod 6 is a free section, used to connect to the underground lining structure 11, and can also be directly fixed to the inner wall of the surrounding rock of the cavern. Specifically, in one embodiment of the present invention, the sleeve 5 and the limiting plate 7 are both made of Q235 steel, and the rod 6 is made of 40 steel.

[0019] The right end of the rod 6 is provided with a pad 8 and a nut 9. The pad 8 is sleeved on the rod 6, and the nut 9 is threaded to the right end of the rod 6. When the pad 8 and the nut 9 move to the left, prestress can be applied to the anchoring section at the left end of the rod 6.

[0020] The end slider 1 is made of 40Cr steel, and its outer diameter is larger than that of the spring 2. The end slider 1 is welded to the rod body 6.

[0021] The spring 2 is a mold compression spring, and its material is SWOSC_V alloy steel.

[0022] The shearing slider 3 is made of 40Cr steel, and the thickness of the shearing slider 3 is greater than twice the pitch of the internal thread 4.

[0023] The sleeve 5 has multiple reinforcing bar heads 10 symmetrically welded on both sides of its outer wall.

[0024] The sleeve 5 includes a cylinder and a plug, with the plug threaded to the left end of the cylinder.

[0025] Specifically, such as Figure 2 , Figure 5 As shown, the displacement-recoverable blast-resistant anchor proposed in this invention is divided into an anchoring section and a free section. The anchoring section extends into the surrounding rock, and the free section connects to the underground lining structure 11 or the inner wall of the surrounding rock. The underground lining structure 11 can be a concrete lining or a lining in the form of corrugated steel support.

[0026] like Figure 6-9As shown, under the action of explosive load, the displacement-recoverable blast-resistant overall working process proposed in this invention is divided into three stages: linear elastic motion stage, shear friction motion stage, and displacement recovery stage. The working stage reached by the anchor bolt is determined according to the magnitude of the external load transmitted from the underground lining structure 11 to the pad plate.

[0027] First, when the external load is less than the ultimate pressure of spring 2 or greater than the ultimate pressure of spring 2 but less than the ultimate shear force of the internal thread 4, the process involves the conventional linear elastic motion stage and the displacement recovery stage. The conventional linear elastic motion stage is further divided into two phases: the elastic element compression stage and the internal thread elastic deformation stage. Under the action of the external load, the end slider 1 first compresses the spring 2, causing it to undergo elastic deformation. When the external load exceeds the ultimate pressure of spring 2, it continues to push the shear slider 3 to elastically compress the internal thread 4. At this time, no plastic failure occurs in the internal components; only linear elastic motion occurs. Subsequently, the end slider 1 recovers its displacement under the rebound action of spring 2. No plastic failure occurs throughout this process, so the load-displacement curve of the displacement recovery stage coincides with that of the linear elastic motion stage.

[0028] When the external load exceeds the ultimate shear strength of the internal thread 4, the shear slider 3 will shear the internal thread 4 to dissipate energy; this is the shear friction motion stage. At this time, the load-displacement curve is wavy, and plastic shear failure occurs at the tip of the internal thread 4; this motion stage is also the energy dissipation stage. Until the entire energy dissipation stage of the internal thread 4 is completely sheared and destroyed, the shear slider 3 continues to press against the limiting plate 7, entering the third linear elastic motion stage. Finally, under the rebound action of the spring 2, the end slider 1 is pushed into the displacement recovery stage.

[0029] In one embodiment of the present invention, the internal thread 4 at the right end of the sleeve 5 cavity is a sawtooth thread. By setting different thread pitch sizes, different energy dissipation effects can be produced. The limiting plate 7 has an external thread with the same size as the internal thread 4, which facilitates locking the shearing slider 3 after all the energy dissipation of the internal thread 4 is completed, so as to continue to play the supporting role of conventional strength anchor rod. In order to increase the anchoring performance of the anchoring section, several steel bar heads 10 are welded to the two side walls of the sleeve of the displacement recoverable anchor rod.

[0030] To reduce the adverse effects of the explosion, the present invention designed the above structural form while keeping the "pressure first, shear later" energy absorption design concept unchanged. Then, the preparation materials and structural form of the present invention were verified through static load performance test. The test results show that after its energy dissipation section has fully played its role, it can still continue to produce the anchoring effect of a conventional strength anchor rod.

[0031] Therefore, the displacement-recoverable blast-resistant anchor proposed in this invention plays a positive role in the blast resistance of underground engineering when reinforcing underground lining structures. It can improve the deformation bearing capacity of underground lining structures, effectively absorb the impact energy under explosive loads, and avoid local instability of underground lining structures, thereby effectively improving the blast-resistant support capacity of underground lining structures.

[0032] The parts of this invention not described in detail are prior art.

Claims

1. A displacement-recoverable explosion-proof anchor bolt, comprising a sleeve (5), a rod body (6), a limiting plate (7), and a spring (2), characterized in that: The sleeve (5) is a straight circular metal tube structure with the left end closed. The right end of its internal cavity is provided with an internal thread (4). The internal thread (4) at the right end of the sleeve (5) cavity is a sawtooth thread, and the inner diameter of the internal thread (4) is smaller than the inner diameter of the cavity. The limiting plate (7) is installed at the opening on the right end of the sleeve (5). The limiting plate (7) is threadedly connected to the internal thread of the sleeve (5), and a through hole is provided in the middle of the limiting plate (7). The rod (6) passes through the through hole of the limiting plate (7), and the left end of the rod (6)... An end slider (1) is fixedly connected to the end of the sleeve (5) and is located at the right end inside the sleeve (5) cavity; a shearing slider (3) is movably sleeved in the middle of the rod (6) and is located inside the sleeve (5) cavity and outside the left end of the internal thread (4). The outer diameter of the shearing slider (3) is larger than the inner diameter of the internal thread (4); the spring (2) is sleeved on the rod (6) and is located between the end slider (1) and the shearing slider (3); the right end of the rod (6) is a free section.

2. The displacement-recoverable explosion-proof anchor bolt according to claim 1, characterized in that: The rod (6) is provided with a pad (8) and a nut (9) on the right end. The pad (8) is fitted on the rod (6) and the nut (9) is threaded to the right end of the rod (6). The pad (8) and the nut (9) are used to apply prestress to the rod (6).

3. The displacement-recoverable explosion-proof anchor bolt according to claim 1, characterized in that: The end slider (1) is made of 40Cr steel and its outer diameter is larger than that of the spring (2).

4. The displacement-recoverable explosion-proof anchor bolt according to claim 1, characterized in that: The spring (2) is a mold compression spring, and its material is SWOSC_V alloy steel.

5. The displacement-recoverable explosion-proof anchor bolt according to claim 1, characterized in that: The shearing slider (3) is made of 40Cr steel and the thickness of the shearing slider (3) is greater than twice the pitch of the internal thread (4).

6. The displacement-recoverable explosion-proof anchor bolt according to claim 1, characterized in that: The sleeve (5) has multiple steel bars (10) symmetrically welded on both sides of its outer wall to increase the anchoring force between the anchor bolt anchoring section and the surrounding rock.

7. The displacement-recoverable explosion-proof anchor bolt according to claim 1, characterized in that: The sleeve (5) includes a cylinder and a plug, with the plug threaded to the left end of the cylinder.

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