Anchor structure with high prestress and large elongation and support method thereof

Abstract

This invention discloses a high-prestress, high-elongation anchoring structure and its support method, comprising multiple high-elongation energy-absorbing anchor cables, multiple high-strength, high-prestress anchor bolts, and a moving layer, an energy-absorbing layer, and a strong anchor layer located above the roadway and distributed sequentially from bottom to top. The high-strength, high-prestress anchor bolts are installed on the moving layer, and the high-elongation energy-absorbing anchor cables are installed on the moving layer, the energy-absorbing layer, and the strong anchor layer. This invention solves the technical problems of frequent anchor cable breakage and poor pressure-bearing capacity of the support system in dynamic pressure roadways, improving the reliability and safety of dynamic pressure roadway support. This invention has good application effects and economic benefits in engineering practice and can meet the technical requirements of coal mine roadway surrounding rock support.

Description

Technical Field

[0001] This invention relates to a high-prestress, high-elongation anchoring structure and its support method, belonging to the field of roadway anchor support. Background Technology

[0002] The complex environment of deep roadways, characterized by "high altitude, high temperature, high humidity, and high stress," results in nonlinear large deformation phenomena in the surrounding rock, including large deformation volume, rapid deformation rate, long duration, strong destructiveness, and severe damage to the support structure. Roadway maintenance is extremely difficult. Conventional anchor bolt prestressing often fails to provide sufficient support resistance to form a prestressed bearing layer for the roof. Insufficient mixing of resin cartridges during ordinary anchor cable anchoring leads to insufficient anchoring force and a tendency for anchor detachment. Furthermore, ordinary anchor cables have a relatively low elongation rate (approximately 7% for a 1×19 strand, 21.8mm diameter anchor cable), while anchor bolts typically have an elongation rate of 12%–15%. This mismatch in elongation rates makes anchor cables prone to breakage when the roadway stress environment deteriorates, leading to large deformation of the surrounding rock and ultimately resulting in poor support performance. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a high-prestress, high-elongation anchoring structure and its support method, which can ensure that when the dynamic pressure in the roadway is significant, the surrounding rock-support system can absorb and release pressure during the coordinated deformation process, reducing the stress in the roadway surrounding rock. Even when large deformation occurs, the support system will not fail, ensuring the stability of the roadway surrounding rock.

[0004] To achieve the above objectives, the present invention employs a high-prestress, high-elongation anchoring structure, comprising multiple high-elongation energy-absorbing anchor cables, multiple high-strength, high-prestress anchor rods, and a moving layer, an energy-absorbing layer, and a strong anchoring layer located above the roadway and distributed sequentially from bottom to top. The high-strength, high-prestress anchor rods are installed on the moving layer, and the high-elongation energy-absorbing anchor cables are installed on the moving layer, the energy-absorbing layer, and the strong anchoring layer.

[0005] The high-elongation energy-absorbing anchor cable is sequentially equipped with a locking device, a high-resistance pressure-relief device, an anchor cable tray, an energy-absorbing pressure-relief structure, and a stirring structure. The locking device, the high-resistance pressure-relief device, and the anchor cable tray are all exposed on the outside of the moving layer. The energy-absorbing pressure-relief structure is located in the energy-absorbing layer, and the stirring structure is located in the strong anchor layer. The high-strength, high-prestressed anchor rod is equipped with an anti-nut reversal structure and an anchor rod tray. The anti-nut reversal structure and the anchor rod tray are exposed on the outside of the moving layer.

[0006] The moving layer consists of high-strength, high-prestressed anchor bolt support and control, and shallow surrounding rock of the roadway. The high-strength, high-prestressed anchor bolts apply pre-tightening force through an anti-nut reversal structure, forming a stable prestressed field in the shallow surrounding rock and creating an integral load-bearing structure. During the deformation of the surrounding rock, the entire structure moves, achieving reasonable control of the shallow fractured surrounding rock. The high-strength, high-prestressed anchor bolts are made of high-strength steel, and the pre-tightening torque is not less than 400 N·m.

[0007] The range of the energy-absorbing layer is the difference between the length of the high-elongation energy-absorbing anchor cable, the length of the high-strength, high-prestressed anchor rod, and the length of the anchorage section of the high-elongation energy-absorbing anchor cable. The energy-absorbing layer deforms in tandem with the surrounding rock through multiple energy-absorbing pressure structures. The elongation of the high-elongation energy-absorbing anchor cable is 10-12%.

[0008] The range of the strong anchor layer is consistent with the length of the anchorage section of the high-elongation energy-absorbing anchor cable.

[0009] In some embodiments, the pre-tightening torque of the high-strength, high-prestressed anchor bolt is applied by pre-tightening with a pneumatic drill or torque wrench, and then using a torque multiplier to increase the pre-tightening torque to the design value.

[0010] In some embodiments, the anti-reverse nut structure includes a preload nut for fastening and an anti-reverse nut mounted on the outside of the preload nut.

[0011] In some embodiments, the high elongation energy-absorbing anchor cable consists of 1×19 strands, has a diameter of 21.8 mm, and a preload of not less than 300 KN.

[0012] In some embodiments, the energy-absorbing pressure structure includes a cage-like structure and a high-hardness energy-absorbing material disposed within the cage-like structure;

[0013] The steel strands of the high-elongation energy-absorbing anchor cable are processed to form an unstretched expansion cavity, which is the cage structure. The high-hardness energy-absorbing material is installed inside the cage structure. The energy-absorbing and pressure-reducing structure is used to improve the elongation of the high-elongation energy-absorbing anchor cable and achieve energy-absorbing and pressure-reducing support during the process of co-deformation with the surrounding rock.

[0014] In some embodiments, the high-hardness energy-absorbing material is any one of high-hardness rubber, polyurethane, starch plastic, and polyimide.

[0015] In some embodiments, the spacing between the energy-absorbing and pressure-absorbing structures on the high-elongation energy-absorbing anchor cable is 0.6m, and the number is not less than 5.

[0016] In some embodiments, the stirring structure is formed by treating the outermost steel strand of the anchoring section of the high elongation energy-absorbing anchor cable to form a cavity and winding multiple turns of iron wire around the remaining steel strands.

[0017] The spacing of the stirring structures on the anchoring section of the high elongation energy-absorbing anchor cable is 0.5m, and the number is 3 to 5.

[0018] In some embodiments, the high-resistance pressure relief device is made of alloy material and includes a protective structure and a compressible gourd-shaped structure, wherein the diameter of the protective structure is larger than the diameter of the compressible gourd-shaped structure.

[0019] A second aspect of the present invention also provides a support method for the aforementioned high-prestress, high-elongation anchoring structure, comprising the following steps:

[0020] Step S1: Fabricate prefabricated components, including:

[0021] Step S1-1: Fabricate multiple energy-absorbing and pressure-absorbing structures on the high-elongation energy-absorbing anchor cable;

[0022] Step S1-2: Set multiple mixing structures in the anchoring section of the high elongation energy-absorbing anchor cable;

[0023] Step S2: Lay and connect the metal mesh, and apply the support material;

[0024] Step S3: Install high-strength, high-prestressed anchor bolts, including:

[0025] Step S3-1: Drill holes using a drilling rig and clean the holes;

[0026] Step S3-2: Install resin anchoring agent and high-strength, high-prestressed anchor bolts. Use an anchor bolt drilling machine to stir the resin anchoring agent for the specified time, then stop stirring and wait for the specified time.

[0027] Step S3-3: Tighten the preload nut to the designed preload force using a preload tool, and then install an anti-reverse nut to form an anti-reverse nut structure;

[0028] Step S4: Install high elongation energy-absorbing anchor cables, including:

[0029] Step S4-1: Drill holes using a drilling rig and clean the holes;

[0030] Step S4-2: Install resin anchoring agent and high elongation energy-absorbing anchor cable. Stir the resin anchoring agent with anchor drilling machine for the specified time, stop stirring and wait for the specified time.

[0031] Step S4-3: Tension the high elongation energy-absorbing anchor cable to the design preload using a tensioning pump.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] (1) High-strength, high-prestressed anchor bolts can effectively prevent the initial delamination of the shallow surrounding rock in the roadway, improve its bearing capacity, and form a moving layer with prestressed bearing capacity of the roof. This can appropriately reduce the support density and increase the tunneling speed. Using high-strength steel as the main bearing material of the anchor bolts can improve the bending and tensile properties of the anchor bolts.

[0034] (2) The high elongation energy-absorbing anchor cable body has a pressure-relief structure and a high resistance pressure-relief device at the tail end, which can enhance the deformation and elongation capacity of the energy-absorbing anchor cable. When the surrounding rock of the roadway undergoes large deformation due to tectonic stress, mining stress, etc., the high elongation energy-absorbing anchor cable can achieve pressure relief support, avoid the phenomenon of anchor cable breakage and loss of support function, and thus form an energy-absorbing layer in the support structure.

[0035] (3) The mixing structure installed in the anchoring section of the high elongation energy-absorbing anchor cable makes the anchoring agent more fully mixed and can also prevent the anchoring agent from flowing down along the hole wall and cable body, thus avoiding affecting the anchoring effect of the anchor cable.

[0036] (4) The anchoring structure of the present invention has good pressure relief capacity and deformation resistance, and can effectively control the deformation of the surrounding rock of the roadway; it can appropriately reduce the support density, save support time, and increase the tunneling speed.

[0037] In summary, this invention has good application effects and economic benefits in engineering practice, and can meet the technical requirements of coal mine roadway surrounding rock support. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the anchoring structure of the present invention;

[0040] Figure 2 This is a schematic diagram of the high elongation energy-absorbing anchor cable of the present invention;

[0041] Figure 3 This is a schematic diagram of the high-strength, high-prestressed anchor rod of the present invention;

[0042] Figure 4 This is a schematic diagram of the anti-nut reversal structure of the present invention;

[0043] Figure 5 This is a schematic diagram of the pressure-absorbing structure of the present invention;

[0044] Figure 6 This is a schematic cross-sectional view of the pressure-absorbing structure of the present invention;

[0045] Figure 7 This is a schematic diagram of the stirring structure of the present invention;

[0046] Figure 8 This is a cross-sectional schematic diagram of the stirring structure of the present invention;

[0047] Figure 9 This is a schematic diagram of the high-resistance pressure relief device of the present invention;

[0048] Figure 10 This is a cross-sectional schematic diagram of the high-resistance pressure relief device of the present invention;

[0049] In the diagram: A, moving layer; B, energy-absorbing layer; C, strong anchor layer; D, tunnel.

[0050] 1. High elongation energy-absorbing anchor cable; 2. Locking device; 3. High resistance pressure relief device; 31. Protective structure; 32. Compressible gourd-shaped structure; 4. Anchor cable tray; 5. Energy-absorbing pressure relief structure; 51. Cage structure; 52. High-hardness energy-absorbing material; 6. Mixing structure; 61. Iron wire; 62. Cavity; 7. High-strength, high-prestress anchor bolt; 8. Anti-nut reversal structure; 81. Pre-tightened nut; 82. Anti-reversal nut; 9. Anchor bolt tray. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of this application and the specific features in the embodiments are detailed descriptions of the technical solutions of this application, rather than limitations on the technical solutions of this application. In the absence of conflict, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0052] In the description of this invention, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of this invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0053] like Figure 1 As shown, a high-prestress, high-elongation anchoring structure includes multiple high-elongation energy-absorbing anchor cables 1, multiple high-strength, high-prestress anchor rods 7, and a moving layer A, an energy-absorbing layer B, and a strong anchoring layer C located above the roadway D and distributed from bottom to top. The high-strength, high-prestress anchor rods 7 are installed on the moving layer A, and the high-elongation energy-absorbing anchor cables 1 are installed on the moving layer A, the energy-absorbing layer B, and the strong anchoring layer C.

[0054] like Figure 2 As shown, the high-elongation energy-absorbing anchor cable 1 is sequentially equipped with a locking device 2, a high-resistance pressure-relief device 3, an anchor cable tray 4, an energy-absorbing pressure-relief structure 5, and a stirring structure 6. The locking device 2, high-resistance pressure-relief device 3, and anchor cable tray 4 are all exposed on the outside of the moving layer A. The energy-absorbing pressure-relief structure 5 is located in the energy-absorbing layer B, and the stirring structure 6 is located in the strong anchor layer C. Figure 3 As shown, the high-strength, high-prestressed anchor rod 7 is equipped with an anti-nut reversal structure 8 and an anchor rod tray 9, which are exposed on the outside of the moving layer A.

[0055] like Figure 1 As shown, the moving layer A is composed of high-strength, high-prestressed anchor bolts 7 for support and control, and shallow surrounding rock of the roadway. Its range is basically consistent with the length of the high-strength, high-prestressed anchor bolts 7. The high-strength, high-prestressed anchor bolts 7 apply a high preload through the anti-nut reversal structure 8, forming a stable prestress field in the shallow surrounding rock and forming an integral bearing structure in the shallow surrounding rock. During the deformation of the surrounding rock, the entire structure moves, achieving reasonable control of the shallow fractured surrounding rock. The high-strength, high-prestressed anchor bolts 7 are made of high-strength steel, such as BHRB 500, and their preload torque is not less than 400 N·m.

[0056] like Figure 1 As shown, the range of the energy-absorbing layer B is the difference between the length of the high-elongation energy-absorbing anchor cable 1, the length of the high-strength, high-prestressed anchor rod 7, and the length of the anchoring section of the high-elongation energy-absorbing anchor cable 1. The energy-absorbing layer B deforms in tandem with the surrounding rock through multiple pressure-absorbing structures 5. Furthermore, the high-resistance pressure-absorbing device 3 is added to the exposed section of the high-elongation energy-absorbing anchor cable 1 to increase the elongation of the high-elongation energy-absorbing anchor cable 1, so that the support system can still not fail when the surrounding rock of the roadway undergoes large deformation, thus achieving the purpose of pressure absorption and pressure relief. The elongation of the high-elongation energy-absorbing anchor cable 1 is 10-12%.

[0057] like Figure 1 As shown, the range of the strong anchor layer C is basically consistent with the length of the anchoring section of the high elongation energy-absorbing anchor cable 1, which anchors the high elongation energy-absorbing anchor cable 1 into the stable rock layer. Multiple stirring structures 6 are installed in the anchoring section of the high elongation energy-absorbing anchor cable 1 to fully stir the anchoring agent during the installation process, increase the contact area between the anchoring agent and the high elongation energy-absorbing anchor cable 1, increase the anchoring force, and at the same time prevent the anchoring agent from flowing down along the hole wall and the cable body of the high elongation energy-absorbing anchor cable 1, which would result in poor anchoring effect and enhance the anchoring effect of the high elongation energy-absorbing anchor cable 1.

[0058] In some embodiments, the high-strength, high-prestressed anchor rod 7 is made of steel grade 500. The pre-tightening torque of the high-strength, high-prestressed anchor rod 7 is applied by first pre-tightening it with a pneumatic drill or torque wrench, then using a torque multiplier to increase the pre-tightening torque to the design value. An anti-nut reversal structure 8 ensures minimal pre-tightening force loss and prevents the nut from loosening, which could lead to a deterioration in the support effect of the high-strength, high-prestressed anchor rod 7. Figure 4 As shown.

[0059] In some embodiments, such as Figure 4 As shown, the anti-reverse nut structure 8 includes a pre-tightening nut 81 for fastening and an anti-reverse nut 82 installed on the outside of the pre-tightening nut 81. Specifically, after the high-strength, high-prestress anchor rod 7 is pre-tightened by the pre-tightening nut 81, an anti-reverse nut 82 is then installed to prevent the loss of pre-tightening force due to loosening of the nut during pre-tightening of a single nut.

[0060] In some embodiments, the high elongation energy-absorbing anchor cable 1 consists of 1×19 strands with a diameter of 21.8 mm and a preload of not less than 300 KN. The elongation of the high elongation energy-absorbing anchor cable 1 is superior to that of ordinary anchor cables, ensuring that the support system does not fail when the surrounding rock of the roadway undergoes large deformation.

[0061] In some embodiments, such as Figure 5 , Figure 6 As shown, the energy-absorbing pressure structure 5 includes a cage-shaped structure 51 and a high-hardness energy-absorbing material 52 disposed within the cage-shaped structure 51.

[0062] The high-elongation energy-absorbing anchor cable 1 is processed by a cage-shaped anchor cable forming machine to form an unstretched expansion cavity, which is the cage-shaped structure 51. The high-hardness energy-absorbing material 52 is filled inside the cage-shaped structure 51. Through the energy-absorbing and pressure-reducing structure 5, the instantaneous response of the cable body when dynamic pressure occurs is enhanced, and the elongation of the high-elongation energy-absorbing anchor cable 1 is increased. During the process of co-deformation with the surrounding rock, energy-absorbing and pressure-reducing support is achieved.

[0063] In some embodiments, the high-hardness energy-absorbing material 52 can be made of high-hardness rubber, polyurethane, starch plastic, polyimide, etc. During installation, the rubber sheet can be inserted after the cage structure is formed, or the high-hardness energy-absorbing material 52 can be heated into a fluid after the cage structure is formed, cooled, and then molded. The high-hardness energy-absorbing material 52 needs to have good compressive strength and low elastic deformation to ensure that the cage structure 51 is not straightened and the high-hardness energy-absorbing material 52 is not damaged when the anchor cable is pre-tightened (300KN). When the dynamic pressure in the roadway is severe, the overall force on the cable exceeds the limit of the high-hardness energy-absorbing material 52. When the cage structure 51 is straightened, the high-hardness energy-absorbing material 52 is crushed and destroyed, thereby achieving the purpose of improving the elongation rate.

[0064] In some embodiments, the spacing of the energy-absorbing and pressure-absorbing structures 5 on the high-elongation energy-absorbing anchor cable 1 is 0.6m, and the number is not less than 5, to ensure that the anchor cable can respond quickly when dynamic pressure occurs, the internal high-hardness energy-absorbing material 52 is destroyed, the cage structure 51 is gradually straightened, and during its cooperative deformation with the surrounding rock, the elastic strain energy of the rock layer is reduced, and the stress of the surrounding rock is reduced.

[0065] In some embodiments, the diameter of the energy-absorbing and pressure-reducing structure 5 of the high-elongation energy-absorbing anchor cable 1 should match the borehole diameter. For a borehole with a diameter of 30 mm, the reasonable diameter of the energy-absorbing and pressure-reducing structure 5 is 25 to 26 mm to prevent obstruction when pushing in and stirring the anchoring agent.

[0066] In some embodiments, such as Figure 7 , Figure 8 As shown, a cavity 62 is formed by processing the outermost steel strand of the anchoring section of the high elongation energy-absorbing anchor cable 1 using a machine, and three turns of iron wire 61 are wound around the remaining steel strands. The diameter of the iron wire 61 is about 1.5 mm, which finally forms the stirring structure 6. The diameter of the stirring structure 6 is about 25-26 mm to prevent obstruction when pushing in and stirring the anchoring agent. The spacing of the stirring structures 6 on the anchoring section of the high elongation energy-absorbing anchor cable 1 is 0.5 m, and the number is 3-5.

[0067] In some embodiments, the wire 61 is wound at least 5 turns to prevent the anchoring agent from flowing down the borehole wall and the cable body of the high elongation energy-absorbing anchor cable 1 during the mixing process, which would result in insufficient anchoring and a poor anchoring effect.

[0068] In some embodiments, such as Figure 9 , Figure 10 As shown, the high-resistance pressure relief device 3 is made of alloy material, such as alloy steel. The high-resistance pressure relief device 3 includes a protective structure 31 and a compressible gourd-shaped structure 32. The protective structure 31 is located at both ends of the compressible gourd-shaped structure 32. When the compressible gourd-shaped structure 32 is subjected to force exceeding the material limit, it will continue to compress until it is flattened. The diameter of the protective structure 31 is larger than that of the compressible gourd-shaped structure 32 to ensure that during the deformation under load, the lock will not enter the compressible gourd-shaped structure 32 or the compressible gourd-shaped structure 32 will not embed into the anchor cable tray 4.

[0069] Furthermore, a second aspect of the present invention provides a support method for the aforementioned high-prestress, high-elongation anchoring structure, comprising the following steps:

[0070] Step S1: Fabricate prefabricated components, including:

[0071] Step S1-1: Use a cage-shaped anchor cable forming machine to process the high elongation energy-absorbing anchor cable 1 to form a cage-shaped structure 51, and fill it with a high-hardness energy-absorbing material 52 of a certain strength, together forming an energy-absorbing and pressure-absorbing structure 5. The diameter of the energy-absorbing and pressure-absorbing structure 5 is about 25-26mm.

[0072] Step S1-2: Install the mixing structure 6 on the anchoring section of the high elongation energy-absorbing anchor cable 1. Use a machine to process the outermost steel strand of the anchoring section of the high elongation energy-absorbing anchor cable 1 to form a cavity 62. Wrap a No. 17 iron wire around the remaining steel strands. The diameter of the iron wire is about 1.5 mm. The final mixing structure 6 has a diameter of about 25-26 mm.

[0073] Step S2: Lay and connect the metal mesh, and install the steel reinforcement beams or steel strips and other support materials;

[0074] Step S3, Install high-strength, high-prestressed anchor bolts 7, including:

[0075] Step S3-1: Drill holes using a drilling rig and clean the holes;

[0076] Step S3-2: Install resin anchoring agent and high-strength, high-prestressed anchor rod 7. Stir the resin anchoring agent with the anchor drilling machine for the specified time, stop stirring and wait for the specified time.

[0077] Step S3-3: Using tools such as a pneumatic drill, torque wrench, and torque multiplier, tighten the preload nut 81 to achieve the designed preload force. Install an additional anti-reverse nut 82 to prevent the nut from loosening and causing loss of preload force.

[0078] Step S4: Install high elongation energy-absorbing anchor cable 1, including:

[0079] Step S4-1: Drill holes using a drilling rig and clean the holes;

[0080] Step S4-2: Install the resin anchoring agent and the high elongation energy-absorbing anchor cable 1. Stir the resin anchoring agent with the anchor drilling machine for the specified time, stop stirring and wait for the specified time.

[0081] Step S4-3: Install a high-resistance pressure relief device 3 between the lock 2 and the anchor cable tray 4, and tension the high-elongation energy-absorbing anchor cable 1 to the design preload using a tensioning pump.

[0082] When performing roadway support according to the above construction method, the construction quality should be guaranteed and relevant safety technical requirements should be met in order to give full play to the characteristics and advantages of the present invention and ensure the stability of the roadway; at the same time, it can improve the mechanization of anchor bolt support construction, select the best construction equipment, optimize the construction process, and increase the speed of roadway support.

[0083] This invention has the following features:

[0084] 1. High-strength, high-prestressed anchor bolts are used to support the shallow surrounding rock of the roadway, reducing the initial delamination of the roof, preventing the gradual destruction of the surface rock strata of the surrounding rock, forming an integral bearing structure in the shallow surrounding rock, and realizing the overall movement during the deformation of the surrounding rock, forming a moving layer in the support structure.

[0085] 2. A cage-like structure capable of extension and deformation is provided in the free section of the high-elongation energy-absorbing anchor cable, and high-hardness energy-absorbing material is filled inside the cage-like structure. When the surrounding rock of the roadway is subjected to instantaneous dynamic pressure, the high-hardness energy-absorbing material is squeezed and destroyed, and the cage-like structure can quickly deform and elongate, increasing the elongation of the high-elongation energy-absorbing anchor cable. During the coordinated movement of the high-elongation energy-absorbing anchor cable and the surrounding rock, it plays the role of absorbing and releasing pressure, forming an energy-absorbing layer in the support structure.

[0086] 3. At certain intervals, the outermost steel strands of the high-elongation energy-absorbing anchor cable are treated to form a mixing structure, ensuring that the anchoring agent is fully mixed, increasing the contact area between the anchoring agent and the high-elongation energy-absorbing anchor cable, thereby achieving the goal of improving the anchoring force of the anchor cable, and anchoring the high-elongation energy-absorbing anchor cable into the stable rock layer to form a strong anchor layer in the support structure.

[0087] 4. Add an anti-reverse nut to the end of the anchor bolt to prevent the nut from turning back and loosening due to uneven surrounding rock surfaces or dynamic pressure, which would affect the support effect; add a high-resistance pressure relief device between the locking device and the anchor plate of the high-elongation energy-absorbing anchor cable to increase the elongation of the cable and enhance the pressure relief effect of the high-elongation energy-absorbing anchor cable.

[0088] This invention solves the technical problems of frequent anchor cable breakage and poor pressure relief capacity of support systems in dynamic pressure roadways, thereby improving the reliability and safety of dynamic pressure roadway support.

[0089] In the description provided herein, numerous specific details are described. However, it is understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0090] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features found in other embodiments but not others, combinations of features from different embodiments are also within the scope of protection of this invention and form different embodiments. For example, in the embodiments described above, those skilled in the art can use them in combination based on known technical solutions and the technical problems to be solved by this application.

[0091] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-prestress, high-elongation anchoring structure, characterized in that, It includes multiple high elongation energy-absorbing anchor cables (1), multiple high strength and high prestressed anchor bolts (7), and a moving layer (A), an energy-absorbing layer (B) and a strong anchor layer (C) located above the roadway (D) and distributed from bottom to top. The high strength and high prestressed anchor bolts (7) are installed on the moving layer (A), and the high elongation energy-absorbing anchor cables (1) are installed on the moving layer (A), the energy-absorbing layer (B) and the strong anchor layer (C). The high elongation energy-absorbing anchor cable (1) is sequentially equipped with a lock (2), a high resistance pressure-relief device (3), an anchor cable tray (4), an energy-absorbing pressure-relief structure (5), and a stirring structure (6). The lock (2), the high resistance pressure-relief device (3), and the anchor cable tray (4) are all exposed on the outside of the moving layer (A). The energy-absorbing pressure-relief structure (5) is located in the energy-absorbing layer (B), and the stirring structure (6) is located in the strong anchor layer (C). The high strength and high prestressed anchor rod (7) is equipped with an anti-nut reversal structure (8) and an anchor rod tray (9). The anti-nut reversal structure (8) and the anchor rod tray (9) are exposed on the outside of the moving layer (A). The moving layer (A) is supported and controlled by high-strength, high-prestressed anchor bolts (7) and the shallow surrounding rock of the roadway. The high-strength, high-prestressed anchor bolts (7) are pre-tightened by an anti-nut reversal structure (8), forming a stable prestressed field in the shallow surrounding rock and an integral bearing structure in the shallow surrounding rock. The entire structure moves during the deformation of the surrounding rock, thus achieving reasonable control of the shallow fractured surrounding rock. The high-strength, high-prestressed anchor bolts (7) are made of high-strength steel and the pre-tightening torque is not less than 400 N·m. The range of the energy-absorbing layer (B) is the difference between the length of the high-elongation energy-absorbing anchor cable (1), the length of the high-strength, high-prestressed anchor rod (7), and the length of the anchorage section of the high-elongation energy-absorbing anchor cable (1). The energy-absorbing layer (B) deforms in tandem with the surrounding rock through multiple pressure-absorbing structures (5). The elongation of the high-elongation energy-absorbing anchor cable (1) is 10-12%. The range of the strong anchor layer (C) is consistent with the length of the anchorage section of the high elongation energy-absorbing anchor cable (1); The energy-absorbing and pressure-reducing structure (5) includes a cage-shaped structure (51) and a high-hardness energy-absorbing material (52) disposed within the cage-shaped structure (51). The steel strands of the high-elongation energy-absorbing anchor cable (1) are processed to form an unstretched expansion cavity, which is the cage-shaped structure (51). The high-hardness energy-absorbing material (52) is installed inside the cage-shaped structure (51). The energy-absorbing and pressure-reducing structure (5) is used to improve the elongation of the high-elongation energy-absorbing anchor cable (1) and achieve energy-absorbing and pressure-reducing support during the process of co-deformation with the surrounding rock. The stirring structure (6) is formed by processing the outermost steel strand of the anchoring section of the high elongation energy-absorbing anchor cable (1) to form a cavity (62) and wrapping multiple turns of iron wire (61) on the remaining steel strands; the spacing of the stirring structures (6) on the anchoring section of the high elongation energy-absorbing anchor cable (1) is 0.5m and the number is 3 to 5. The high-resistance pressure relief device (3) includes a protective structure (31) and a compressible gourd-shaped structure (32), wherein the diameter of the protective structure (31) is larger than the diameter of the compressible gourd-shaped structure (32).

2. The anchoring structure with high prestress and large elongation according to claim 1, characterized in that, The method for applying the pre-tightening torque of the high-strength, high-prestressed anchor rod (7) is to pre-tighten it with a pneumatic drill or torque wrench, and then use a torque multiplier to increase the pre-tightening torque to the design value.

3. The anchorage structure with high prestress and large elongation according to claim 1, characterized in that, The anti-reverse nut structure (8) includes a preload nut (81) for fastening and an anti-reverse nut (82) installed on the outside of the preload nut (81).

4. The anchorage structure with high prestress and large elongation according to claim 1, characterized in that, The high elongation energy-absorbing anchor cable (1) consists of 1×19 strands, with a diameter of 21.8 mm and a preload of not less than 300 KN.

5. The anchoring structure with high prestress and large elongation according to claim 1, characterized in that, The high-hardness energy-absorbing material (52) is any one of high-hardness rubber, polyurethane, starch plastic, and polyimide.

6. The anchoring structure with high prestress and large elongation according to claim 1, characterized in that, The spacing of the energy-absorbing and pressure-absorbing structures (5) on the high-elongation energy-absorbing anchor cable (1) is 0.6m, and the number is not less than 5.

7. The anchoring structure with high prestress and large elongation according to claim 1, characterized in that, The high-resistance pressure relief device (3) is made of alloy material.

8. A support method for a high-prestress, high-elongation anchorage structure as described in any one of claims 1-7, characterized in that, Includes the following steps: Step S1: Fabricate prefabricated components, including: Step S1-1: Fabricate multiple energy-absorbing pressure structures (5) on the high elongation energy-absorbing anchor cable (1); Step S1-2: Set multiple mixing structures (6) in the anchoring section of the high elongation energy-absorbing anchor cable (1); Step S2: Lay and connect the metal mesh, and apply the support material; Step S3, Install high-strength, high-prestressed anchor bolts (7), including: Step S3-1: Drill holes using a drilling rig and clean the holes; Step S3-2: Install resin anchoring agent and high-strength, high-prestressed anchor rod (7). Stir the resin anchoring agent with an anchor rod drilling machine for the specified time, stop stirring and wait for the specified time. Step S3-3: Tighten the preload nut (81) with a preload tool to achieve the designed preload force, and then install an anti-reverse nut (82) to form an anti-reverse nut structure (8). Step S4, Installing high elongation energy-absorbing anchor cable (1), including: Step S4-1: Drill holes using a drilling rig and clean the holes; Step S4-2: Install resin anchoring agent and high elongation energy-absorbing anchor cable (1). Stir the resin anchoring agent with anchor drilling machine for the specified time, stop stirring and wait for the specified time. Step S4-3: Tension the high elongation energy-absorbing anchor cable (1) to the designed preload using a tensioning pump.

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