High-prestress and large-elongation anchoring structure and supporting method thereof

Abstract

The invention discloses a high-prestress and large-ductility anchoring structure and a supporting method thereof.The high-prestress and large-ductility anchoring structure comprises a plurality of high-ductility energy absorption anchor cables, a plurality of high-strength and high-prestress anchor rods, a moving layer, an energy absorption layer and a strong anchoring layer, and the moving layer, the energy absorption layer and the strong anchoring layer are located above a roadway and sequentially distributed from bottom to top; and the high-elongation energy-absorbing anchor cable is mounted on the moving layer, the energy-absorbing layer and the strong anchoring layer. The technical problems that a dynamic pressure roadway anchor cable is frequently snapped, the yielding capacity of a supporting system is poor and the like are solved, and the reliability and safety of dynamic pressure roadway supporting are improved. The method has good application effect and economic benefit in engineering practice, and can meet the technical requirements of coal mine tunnel surrounding rock support.

Description

Technical Field

[0001] The invention relates to an anchoring structure with high prestress and large elongation and a supporting method thereof, belonging to the field of tunnel anchor support. Background Art

[0002] The complex environment of "three highs and one disturbance" in deep tunnels causes the surrounding rock to exhibit nonlinear large deformation phenomena such as large deformation, fast deformation rate, long duration, strong destructiveness, and serious damage to the support body. The tunnel maintenance is extremely difficult, and the anchor prestressing in the conventional support form often cannot provide sufficient support resistance to form a prestressed bearing layer of the roof; the resin roll is not sufficiently stirred during anchoring of ordinary anchor cables, resulting in insufficient anchoring force and easy unanchoring; and the elongation of ordinary anchor cables is relatively small (1×19 strands, 21.8 diameter anchor cables, the elongation is about 7%), while the elongation of anchor rods is generally around 12% to 15%. The elongation of the two is not coordinated. When the stress environment of the tunnel deteriorates and causes large deformation of the surrounding rock, the anchor cables are prone to breakage, which ultimately leads to poor support effect. Summary of the invention

[0003] In view of the problems existing in the above-mentioned prior art, the present invention provides an anchoring structure with high prestress and large elongation and a support method thereof, which can ensure that when the dynamic pressure of the tunnel becomes obvious, the surrounding rock-support system can absorb and yield pressure during the collaborative deformation process, thereby reducing the stress of the tunnel surrounding rock. Even when large deformation occurs, the support system still does not fail, thereby ensuring the stability of the tunnel surrounding rock.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts a high prestressed and large elongation anchoring structure, which includes a plurality of high elongation energy-absorbing anchor cables, a plurality of high-strength and high prestressed anchor rods, and a moving layer, an energy-absorbing layer and a strong anchor layer located above the tunnel and distributed in sequence from bottom to top, wherein the high-strength and high prestressed 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 anchor layer;

[0005] The high-elongation energy-absorbing anchor cable is sequentially equipped with a lock, a high-resistance pressure-relieving device, an anchor cable tray, a pressure-relieving and pressure-relieving structure, and a stirring structure. The lock, the high-resistance pressure-relieving device, and the anchor cable tray are all exposed outside the moving layer. The pressure-relieving and pressure-relieving structure is located in the energy-absorbing layer, and the stirring structure is located in the strong anchor layer. The high-strength and 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 outside the moving layer.

[0006] The moving layer is composed of high-strength and high-prestressed anchor support control and shallow surrounding rock of the tunnel. The high-strength and high-prestressed anchor applies pre-tightening force through the anti-nut reversal structure, forms a stable prestressed field in the shallow surrounding rock, forms an overall bearing structure in the shallow surrounding rock, realizes overall movement during the deformation of the surrounding rock, and realizes reasonable control of the shallow broken surrounding rock; the high-strength and high-prestressed anchor is made of high-strength steel, and the pre-tightening torque is not less than 400N·m;

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

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

[0009] In some embodiments, the method for applying the pre-tightening torque of the high-strength and high-prestressed anchor rod is to pre-tighten it with a pneumatic drill or a torque wrench, and then use a torque multiplier to increase the pre-tightening torque to the design value.

[0010] In some embodiments, the anti-nut reversal structure includes a pre-tightening nut for tightening and an anti-reversal nut installed outside the pre-tightening nut.

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

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

[0013] The cable body steel strands of the high elongation energy absorbing anchor cable are processed to form an untwisted expansion cavity, namely the cage structure, and the high hardness energy absorbing material is installed inside the cage structure. The energy absorbing and pressure-absorbing structure is used to increase the elongation of the high elongation energy absorbing anchor cable, and realize the energy absorbing and pressure-absorbing support in the process of coordinated 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 stress-absorbing structures on the high elongation energy absorbing anchor cable is 0.6 m, and the number of the structures is no less than 5.

[0016] In some embodiments, the stirring structure is formed by processing a steel strand at the outermost side 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 between the stirring structures on the anchoring section of the high elongation energy absorbing anchor cable is 0.5 m, and the number of the stirring structures is 3 to 5.

[0018] In some embodiments, the high-resistance pressure-releasing 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 greater than the diameter of the compressible gourd-shaped structure.

[0019] The second aspect of the present invention further provides a method for supporting the anchor structure with high prestress and large elongation, comprising the following steps:

[0020] Step S1, making a prefabricated part, comprising:

[0021] Step S1-1, making a plurality of energy-absorbing and pressure-reducing structures on the high-elongation energy-absorbing anchor cable;

[0022] Step S1-2, setting a plurality of stirring structures in the anchoring section of the high elongation energy absorbing anchor cable;

[0023] Step S2, laying and connecting metal meshes and applying supporting materials;

[0024] Step S3, installing high-strength and high-prestressed anchor rods, comprising:

[0025] Step S3-1, drilling and cleaning the holes using a drilling machine;

[0026] Step S3-2, installing the resin anchor and the high-strength and high-prestressed anchor, stirring the resin anchor with an anchor drill for a specified time, stopping stirring and waiting for a specified time;

[0027] Step S3-3, tighten the pre-tightening nut by a pre-tightening tool to reach the designed pre-tightening force, and then install an anti-reversal nut to form an anti-nut reversal structure;

[0028] Step S4, installing high elongation energy absorbing anchor cables, comprising:

[0029] Step S4-1, drilling and cleaning the holes using a drilling machine;

[0030] Step S4-2, installing the resin anchor and the high elongation energy absorbing anchor cable, stirring the resin anchor with a bolting machine for a specified time, stopping stirring and waiting for a specified time;

[0031] Step S4-3: tensioning the high elongation energy-absorbing anchor cable to the designed preload force by means of a tensioning pump.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The use of high-strength and high-prestressed anchor rods can effectively prevent the initial delamination of the shallow surrounding rock of the tunnel, improve its bearing capacity, and form a mobile layer with prestressed bearing on the top plate, thereby appropriately reducing the support density and increasing the tunnel excavation speed. The use of high-strength steel as the main bearing material of the anchor rod can improve the bending and tensile properties of the anchor rod.

[0034] (2) The high-elongation energy-absorbing anchor cable has a pressure-absorbing structure on the cable body and a high-resistance pressure-releasing 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 tunnel undergoes large deformation due to tectonic stress, mining stress, etc., the high-elongation energy-absorbing anchor cable can provide pressure-releasing support, thus avoiding the phenomenon of the anchor cable breaking and losing its supporting function, thereby forming an energy-absorbing layer in the support structure.

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

[0036] (4) The anchoring structure of the present invention has good pressure-relieving capacity and anti-deformation effect through the synergistic effect of each layer, and can effectively control the deformation of the surrounding rock of the tunnel; it can appropriately reduce the support density, save support time, and increase the tunnel excavation speed.

[0037] In summary, the present invention has good application effect and economic benefit in engineering practice, and can meet the technical requirements of surrounding rock support in coal mine tunnels. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

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

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

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

[0042] Figure 4 It is a schematic diagram of the nut reversal prevention structure of the present invention;

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

[0044] Figure 6 It is a cross-sectional schematic diagram of the pressure-absorbing and pressure-reducing structure of the present invention;

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

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

[0047] Fig. 9 A schematic diagram of a high-resistance pressure-yielding device of the present invention;

[0048] Fig.10 It is a cross-sectional schematic diagram of the high-resistance pressure-yielding device of the present invention;

[0049] In the figure: A, moving layer, B, energy absorbing layer, C, strong anchor layer, D, roadway;

[0050] 1. High elongation energy-absorbing anchor cable; 2. Lock; 3. High resistance pressure-yielding device, 31. Protection structure, 32. Compressible gourd-shaped structure; 4. Anchor cable tray; 5. Pressure-absorbing and pressure-yielding structure, 51. Cage-shaped structure, 52. High-hardness energy-absorbing material; 6. Stirring structure, 61. Iron wire, 62. Cavity; 7. High-strength and high-prestressed anchor rod; 8. Anti-nut reversal structure, 81. Pre-tightening nut, 82. Anti-reversal nut; 9. Anchor rod tray. DETAILED DESCRIPTION

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

[0052] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection content of the present invention.

[0053] like Figure 1 As shown, a high prestressed and large elongation anchoring structure comprises a plurality of high elongation energy absorbing anchor cables 1, a plurality of high-strength and high prestressed anchor rods 7, and a moving layer A, an energy absorbing layer B and a strong anchor layer C located above a tunnel D and sequentially distributed from bottom to top, wherein the high-strength and high prestressed 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 anchor layer C;

[0054] like Figure 2 As shown, the high elongation energy absorbing anchor cable 1 is sequentially installed with a lock 2, a high resistance pressure-releasing device 3, an anchor cable tray 4, an absorption and pressure-releasing structure 5 and a stirring structure 6. The lock 2, the high resistance pressure-releasing device 3 and the anchor cable tray 4 are all exposed outside the moving layer A, the absorption and pressure-releasing 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 and high-prestressed anchor rod 7 is installed with a nut-reversal-proof structure 8 and an anchor rod tray 9, and the nut-reversal-proof structure 8 and the anchor rod tray 9 are exposed outside the moving layer A;

[0055] like Figure 1 As shown, the moving layer A is composed of high-strength and high-prestressed anchor rods 7 supporting and controlling and shallow surrounding rocks of the tunnel, and its range is basically consistent with the length of the high-strength and high-prestressed anchor rods 7. The high-strength and high-prestressed anchor rods 7 apply a relatively high pre-tightening force through the anti-nut reversal structure 8, forming a stable prestressed field in the shallow surrounding rocks, forming an overall bearing structure in the shallow surrounding rocks, realizing overall movement during the deformation of the surrounding rocks, and realizing reasonable control of the shallow broken surrounding rocks; wherein, the high-strength and high-prestressed anchor rods 7 are made of high-strength steel, such as BHRB 500, and the pre-tightening torque thereof is not less than 400N·m;

[0056] like Figure 1 As shown, the range of the energy absorption layer B is the difference between the cable length of the high elongation energy absorption anchor cable 1, the rod length of the high-strength and high-prestressed anchor rod 7, and the anchoring section length of the high elongation energy absorption anchor cable 1. The energy absorption layer B cooperates with the surrounding rock to deform through multiple absorption and pressure-releasing structures 5; and the high-resistance pressure-releasing device 3 is added to the exposed section of the high elongation energy absorption anchor cable 1 to increase the elongation of the high elongation energy absorption anchor cable 1, so that it can adapt to the large deformation of the tunnel surrounding rock, and the support system still does not fail, so as to achieve the purpose of absorption and pressure-releasing; wherein, the elongation of the high elongation energy absorption 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, and the high elongation energy absorbing anchor cable 1 is anchored into the stable rock formation, and a plurality of 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 of the high elongation energy absorbing anchor cable 1, thereby increasing the contact area between the anchoring agent and the high elongation energy absorbing anchor cable 1 and increasing the anchoring force, while preventing the anchoring agent from flowing down along the hole wall and the cable body of the high elongation energy absorbing anchor cable 1, resulting in poor anchoring effect, thereby enhancing the anchoring effect of the high elongation energy absorbing anchor cable 1.

[0058] In some embodiments, the steel grade of the high-strength and high-prestressed anchor rod 7 is 500. The pre-tightening torque of the high-strength and high-prestressed anchor rod 7 is applied by pre-tightening with a pneumatic drill or a torque wrench, and then using a torque multiplier to increase the pre-tightening torque to the design value. The anti-nut reversal structure 8 is used to ensure that the pre-tightening force loss is small, and the loosening of the nut is prevented, which causes the support effect of the high-strength and high-prestressed anchor rod 7 to deteriorate. Figure 4 shown.

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

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

[0061] In some embodiments, Figure 5 , Figure 6 As shown, the energy absorption and compression structure 5 includes a cage structure 51 and a high-hardness energy absorption material 52 disposed in the cage structure 51;

[0062] The cage structure anchor cable forming machine processes the cable body steel strands of the high elongation energy absorbing anchor cable 1 to form an untwisted expansion cavity, namely the cage structure 51, and the high hardness energy absorbing material 52 is filled inside the cage structure 51. The energy absorption and pressure-absorbing structure 5 is used to enhance the instantaneous response of the cable body when dynamic pressure occurs, and improve the elongation of the high elongation energy absorbing anchor cable 1. In the process of coordinated deformation with the surrounding rock, the energy absorption and pressure-absorbing support is realized.

[0063] In some embodiments, the high-hardness energy-absorbing material 52 can be made of high-hardness rubber, polyurethane, starch plastic, polyimide and other materials. 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, and then formed after cooling. The high-hardness energy-absorbing material 52 needs to have good compression resistance and low elastic deformation to ensure that when the anchor cable is pre-tightened (300KN), the cage structure 51 is not straightened and the high-hardness energy-absorbing material 52 is not damaged; when the dynamic pressure of the roadway appears violent, the overall force of the cable body exceeds the limit of the high-hardness energy-absorbing material 52, and when the cage structure 51 is straightened, the high-hardness energy-absorbing material 52 is squeezed and damaged, thereby achieving the purpose of improving the elongation.

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

[0065] In some embodiments, the diameter of the energy absorbing and stress absorbing 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 stress absorbing structure 5 is 25-26 mm to prevent obstruction when pushing and stirring the anchoring agent.

[0066] In some embodiments, Figure 7 , Figure 8 As shown, the outermost steel strand of the anchoring section of the high elongation energy absorbing anchor cable 1 is processed by a machine to form a cavity 62, and 3 turns of iron wire 61 are wound around the remaining steel strands. The diameter of the iron wire 61 is about 1.5 mm, and finally the stirring structure 6 is formed. The diameter of the stirring structure 6 is about 25-26 mm to prevent obstruction when pushing and stirring the anchor agent; the spacing between 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 iron wire 61 is wound for no less than 5 turns to prevent the anchoring agent from flowing down along the borehole wall and the cable body of the high elongation energy absorbing anchor cable 1 during the stirring process, resulting in insufficient anchoring and poor anchoring effect.

[0068] In some embodiments, Fig. 9 , Fig.10 As shown, the high-resistance pressure-releasing device 3 is made of an alloy material, such as alloy steel. The high-resistance pressure-releasing 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 a force exceeding the material limit, it will continue to be compressed until it is flattened. The diameter of the protective structure 31 is larger than the compressible gourd-shaped structure 32, ensuring that during the load deformation process, the lock will not enter the compressible gourd-shaped structure 32 and the compressible gourd-shaped structure 32 will not be embedded in the anchor tray 4.

[0069] In addition, the second aspect of the present invention further provides a method for supporting the anchor structure with high prestress and large elongation, comprising the following steps:

[0070] Step S1, making a prefabricated part, comprising:

[0071] Step S1-1, using a cage structure anchor cable forming machine to process a high elongation energy absorbing anchor cable 1 to form a cage structure 51, and filling it with a high hardness energy absorbing material 52 of a certain strength to form an energy absorbing and pressure absorbing structure 5, wherein the diameter of the energy absorbing and pressure absorbing structure 5 is about 25-26 mm;

[0072] Step S1-2, installing a stirring structure 6 at the anchoring section of the high elongation energy absorbing anchor cable 1, processing the outermost steel strands of the anchoring section of the high elongation energy absorbing anchor cable 1 by a machine to form a cavity 62, and wrapping a circle of No. 17 iron wire around the remaining steel strands, the diameter of the iron wire is about 1.5 mm, and the stirring structure 6 finally formed has a diameter of about 25 to 26 mm;

[0073] Step S2, laying and connecting metal meshes, and installing supporting materials such as steel joists or steel belts;

[0074] Step S3, installing the high-strength and high-prestressed anchor rod 7, comprises:

[0075] Step S3-1, drilling and cleaning the holes using a drilling machine;

[0076] Step S3-2, installing the resin anchor and the high-strength and high-prestressed anchor 7, stirring the resin anchor with an anchor drill for a specified time, stopping stirring and waiting for a specified time;

[0077] Step S3-3, tighten the preload nut 81 to reach the designed preload force by using tools such as a pneumatic drill, a torque wrench, a torque multiplier, etc., and additionally install an anti-reverse nut 82 to prevent the nut from loosening and causing loss of preload force;

[0078] Step S4, installing the high elongation energy absorbing anchor cable 1, comprises:

[0079] Step S4-1, drilling and cleaning the holes using a drilling machine;

[0080] Step S4-2, installing the resin anchor and the high elongation energy absorbing anchor cable 1, stirring the resin anchor with a bolting machine for a specified time, stopping stirring and waiting for a specified time;

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

[0082] When carrying out tunnel support according to the above-mentioned construction method, the construction quality should be guaranteed and the relevant safety and technical requirements should be met to give full play to the characteristics and advantages of the present invention and ensure the stability of the tunnel; at the same time, the mechanization degree of anchor support construction can be improved, construction machinery and tools can be optimized, construction technology can be optimized, and the speed of tunnel support can be increased.

[0083] The present invention has the following characteristics:

[0084] 1. Use high-strength and high-prestressed anchor rods to support the shallow surrounding rock of the tunnel, reduce the initial separation of the roof, prevent the gradual destruction of the surface rock layer of the tunnel surrounding rock, form an overall bearing structure in the shallow surrounding rock, realize overall movement during the deformation of the surrounding rock, and form a moving layer in the support structure;

[0085] 2. A cage-shaped structure that can be extended and deformed is provided in the free section of the high-elongation energy-absorbing anchor cable, and high-hardness energy-absorbing materials are filled in the cage-shaped structure. When the surrounding rock of the tunnel is subjected to instantaneous dynamic pressure, the high-hardness energy-absorbing material is squeezed and damaged, and the cage-shaped structure can deform and elongate quickly, thereby increasing the elongation of the high-elongation energy-absorbing anchor cable. In the process of coordinated movement between the high-elongation energy-absorbing anchor cable and the surrounding rock, the effect of absorbing pressure is achieved, thus forming an energy-absorbing layer in the support structure.

[0086] 3. In the anchoring section of the high elongation energy-absorbing anchor cable, the outermost steel strands are processed at intervals of a certain length to form a stirring structure, ensure that the anchoring agent is fully stirred, increase the contact area between the anchoring agent and the high elongation energy-absorbing anchor cable, achieve the goal of improving the anchoring force of the anchor cable, and anchor the high elongation energy-absorbing anchor cable into the stable rock formation to form a strong anchor layer in the support structure;

[0087] 4. Add an anti-reversal nut at the tail of the anchor rod to prevent the nut from reversing and loosening due to uneven surrounding rock surface and dynamic pressure, which may affect the support effect. Add a high-resistance pressure-relieving device between the lock of the high-elongation energy-absorbing anchor cable and the anchor cable tray to increase the elongation of the cable body and enhance the pressure-relieving effect of the high-elongation energy-absorbing anchor cable.

[0088] The invention solves the technical problems of frequent breaking of anchor cables in dynamic pressure tunnels and poor pressure-relieving capacity of support systems, thereby improving the reliability and safety of dynamic pressure tunnel support.

[0089] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can 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] In addition, those skilled in the art will understand that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments also means being within the scope of protection of the present invention and forming different embodiments. For example, in the above embodiments, those skilled in the art can use them in combination according to the known technical solutions and the technical problems to be solved by this application.

[0091] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. An anchoring structure with high prestress and large elongation, characterized in that: The invention comprises a plurality of high-elongation energy-absorbing anchor cables (1), a plurality of high-strength and high-prestressed anchor rods (7), and a moving layer (A), an energy-absorbing layer (B) and a strong anchor layer (C) located above a tunnel (D) and distributed in sequence from bottom to top, wherein the high-strength and high-prestressed 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 anchor layer (C); The high-elongation energy-absorbing anchor cable (1) is provided with a lock (2), a high-resistance pressure-releasing device (3), an anchor cable tray (4), a pressure-releasing structure (5) and a stirring structure (6) in sequence; the lock (2), the high-resistance pressure-releasing device (3) and the anchor cable tray (4) are all exposed outside the moving layer (A); the pressure-releasing structure (5) is located in the energy-absorbing layer (B); the stirring structure (6) is located in the strong anchor layer (C); the high-strength and high-prestressed anchor rod (7) is provided with a nut-reversal prevention structure (8) and an anchor rod tray (9); the nut-reversal prevention structure (8) and the anchor rod tray (9) are exposed outside the moving layer (A); The moving layer (A) is composed of high-strength and high-prestressed anchor rods (7) supporting and controlling and shallow surrounding rock of the tunnel. The high-strength and high-prestressed anchor rods (7) apply pre-tightening force through the anti-nut reversal structure (8), forming a stable pre-stressed field in the shallow surrounding rock, forming an overall bearing structure in the shallow surrounding rock, achieving overall movement during the deformation process of the surrounding rock, and realizing reasonable control of the shallow broken surrounding rock; the high-strength and high-prestressed anchor rods (7) are made of high-strength steel, and the pre-tightening torque is not less than 400N·m; The energy absorbing layer (B) has a range of the difference between the cable length of the high elongation energy absorbing anchor cable (1), the rod length of the high-strength and high-prestressed anchor rod (7), and the anchoring section length of the high elongation energy absorbing anchor cable (1). The energy absorbing layer (B) deforms in coordination with the surrounding rock through a plurality of absorbing and yielding 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 anchoring section of the high elongation energy absorbing anchor cable (1).

2. The anchor 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 and high-prestressed anchor rod (7) is to use a pneumatic drill or a torque wrench for pre-tightening, and then use a torque multiplier to increase the pre-tightening torque to a designed value.

3. The anchor structure with high prestress and large elongation according to claim 1, characterized in that: The nut anti-reversal structure (8) comprises a pre-tightening nut (81) for tightening and an anti-reversal nut (82) installed outside the pre-tightening nut (81).

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

5. The anchor structure with high prestress and large elongation according to claim 1, characterized in that: The energy-absorbing and decompression-reducing structure (5) comprises a cage-shaped structure (51) and a high-hardness energy-absorbing material (52) arranged in the cage-shaped structure (51); The cable body steel strands of the high elongation energy absorbing anchor cable (1) are processed to form an untwisted expansion cavity, namely the cage structure (51), and the high hardness energy absorbing material (52) is installed inside the cage structure (51). The energy absorption and compression structure (5) is used to increase the elongation of the high elongation energy absorbing anchor cable (1) and realize energy absorption and compression support in the process of coordinated deformation with the surrounding rock.

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

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

8. The anchor structure with high prestress and large elongation according to claim 1, characterized in that: The stirring structure (6) is formed by processing a steel strand at the outermost side of the anchoring section of the high-elongation energy-absorbing anchor cable (1) to form a cavity (62), and winding a plurality of turns of iron wire (61) around the remaining steel strands; The spacing between the stirring structures (6) on the anchoring section of the high-elongation energy-absorbing anchor cable (1) is 0.5 m, and the number of the stirring structures (6) is 3 to 5.

9. The anchor structure with high prestress and large elongation according to claim 1, characterized in that: The high-resistance pressure-releasing device (3) is made of alloy material, and comprises a protective structure (31) and a compressible gourd-shaped structure (32), wherein the diameter of the protective structure (31) is greater than the diameter of the compressible gourd-shaped structure (32).

10. A method for supporting an anchor structure with high prestress and large elongation as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: Step S1, making a prefabricated part, comprising: Step S1-1, manufacturing a plurality of energy-absorbing and pressure-reducing structures (5) on the high-elongation energy-absorbing anchor cable (1); Step S1-2, arranging a plurality of stirring structures (6) in the anchoring section of the high-elongation energy-absorbing anchor cable (1); Step S2, laying and connecting metal meshes and applying supporting materials; Step S3, installing high-strength and high-prestressed anchor rods (7), comprises: Step S3-1, drilling and cleaning the holes using a drilling machine; Step S3-2, installing the resin anchor and the high-strength and high-prestressed anchor (7), stirring the resin anchor with an anchor drill for a specified time, stopping stirring and waiting for a specified time; Step S3-3, tightening the pre-tightening nut (81) by a pre-tightening tool to reach the designed pre-tightening force, and then installing an anti-reversal nut (82) to form an anti-nut reversal structure (8); Step S4, installing the high elongation energy absorbing anchor cable (1), comprises: Step S4-1, drilling and cleaning the holes using a drilling machine; Step S4-2, installing the resin anchor and the high elongation energy absorbing anchor cable (1), stirring the resin anchor with a bolting machine for a specified time, stopping stirring and waiting for a specified time; Step S4-3, tensioning the high elongation energy absorbing anchor cable (1) to a designed preload force by means of a tensioning pump.

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