Tunnel energy absorption and pressure relief support system and method

Abstract

The application relates to the technical field of tunnel construction, and provides a tunnel energy-absorbing pressure-releasing supporting system and method, which comprises a flexible concrete spraying layer, a flexible steel mesh, a steel frame mesh, a damping anchor rod and a concrete layer, the flexible concrete spraying layer is used for being arranged on a tunnel rock wall, the flexible steel mesh is arranged on the flexible concrete spraying layer, the steel frame mesh is arranged on the flexible steel mesh, the damping anchor rod is used for being anchored in the tunnel rock wall after sequentially penetrating and connecting the steel frame mesh, the flexible steel mesh and the flexible concrete spraying layer, and the concrete layer is arranged on the damping anchor rod, the steel frame mesh and the flexible steel mesh, basalt fibers and coarse polypropylene fibers are doped in the flexible concrete spraying layer, and the flexible steel mesh is a concave negative Poisson's ratio honeycomb mesh structure. Through the above structural arrangement, the overall energy absorption and pressure release prevent the damage of rock burst to the overall structure, thereby guaranteeing the supporting effectiveness and improving the safety.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and more specifically, to a tunnel pressure-absorbing support system and method. Background Technology

[0002] Tunnels are engineering structures buried underground or within mountains, typically used as transportation tunnels, water conservancy tunnels, and mining tunnels. During tunnel construction and use, especially in high-stress tunnel projects, the elastic deformation energy stored in the tunnel rock mass is suddenly released under the effects of blasting disturbance and excavation unloading. This leads to frequent, sudden, random, and hazardous rockburst disasters such as cracking, spalling, and ejection in the high-stress tunnel rock walls, posing unstable safety hazards to the project, transportation equipment, and personnel.

[0003] Currently, the support structure for tunnel rock walls typically involves anchoring the support mesh or support frame to the tunnel rock wall using anchors. This traditional support structure generally relies solely on its high rigidity to resist most of the kinetic energy of the fractured rock mass during a rockburst. Existing rockburst hazards are generally classified into minor, moderate, severe, and extremely severe rockbursts. For the first two levels of rockbursts, existing traditional support structures can generally control them well. However, for the latter two levels of rockbursts, traditional support structures are insufficient to provide good control. In severe cases, this can lead to anchor breakage, twisting and breakage of the support mesh or support frame, resulting in unstable and unsafe situations such as rock fragment ejection and tilting and collapse of the support structure. Summary of the Invention

[0004] The technical problem to be solved by this invention is: how to improve the stability and safety of rockburst sections in high-stress tunnels.

[0005] This invention provides a tunnel energy-absorbing and pressure-retaining support system, comprising a flexible concrete sprayed layer, a flexible steel mesh, a steel frame mesh, shock-absorbing anchors, and a concrete layer. The flexible concrete sprayed layer is used to cover the tunnel rock wall. The flexible steel mesh covers the flexible concrete sprayed layer, and the steel frame mesh covers the flexible steel mesh. The shock-absorbing anchors pass through and connect the steel frame mesh, the flexible steel mesh, and the flexible concrete sprayed layer in sequence, and are then anchored within the tunnel rock wall. The concrete layer covers the shock-absorbing anchors and the steel frame mesh. The flexible steel mesh, wherein the flexible concrete spray layer is doped with basalt fiber and coarse polypropylene fiber, the flexible steel mesh is a concave negative Poisson's ratio honeycomb mesh structure, the shock-absorbing anchor rod includes a rod body, a sleeve and a connector, the outer wall of the sleeve is used to abut against the wall of the anchor hole opened in the tunnel rock wall, the rod body is used to anchor in the anchor hole, the sleeve is sleeved on the rod body and elastically connected to the rod body, the connector is connected to the end of the rod body away from the tunnel rock wall and pressed onto the steel mesh.

[0006] Optionally, the shock-absorbing anchor rod further includes an elastic deformation member, which is sleeved on the rod body and connected to the end of the sleeve.

[0007] Optionally, the shock-absorbing anchor rod further includes a third spring, the sleeve includes a first sleeve and a second sleeve respectively sleeved on the rod body, the elastic deformation member includes a first elastic deformation member and a second elastic deformation member, the first elastic deformation member is connected to the end of the first sleeve near the second sleeve, the second elastic deformation member is connected to the end of the second sleeve near the first sleeve, and the third spring is sleeved on the rod body and connected between the first elastic deformation member and the second elastic deformation member.

[0008] Optionally, the ends of the first sleeve and the second sleeve near the bottom of the anchoring hole are both configured as wedge-shaped structures.

[0009] Optionally, the shock-absorbing anchor rod further includes a first spring and a second spring respectively sleeved on the rod body. The first spring is placed inside the first sleeve, with one end connected to the rod body and the other end connected to the first elastic deformation member. The second spring is placed inside the second sleeve, with one end connected to the rod body and the other end connected to the second elastic deformation member.

[0010] Optionally, the rod body includes a continuously arranged connecting segment, a main body segment, and an anchoring segment. The connecting segment is connected to the connector, and the anchoring segment is used to anchor to the bottom of the anchoring hole. The structural cell constituting the main body segment is a concave negative Poisson's ratio structural cell.

[0011] Optionally, the tunnel pressure-absorbing support system further includes an anchoring agent, the end of the anchoring section is a wedge-shaped structure, and the anchoring section is provided with external threads. The anchoring agent is used to be placed at the bottom of the anchoring hole, and the anchoring section is anchored to the anchoring agent.

[0012] Optionally, the shock-absorbing anchor rod further includes a fourth spring, which is sleeved on the connecting section and its two ends abut against the connecting member and the steel frame mesh, respectively.

[0013] Optionally, the steel frame mesh includes axial steel strips and annular steel strips. The axial steel strips are arranged along the tunnel axis, and multiple axial steel strips are spaced apart. Multiple annular steel strips are arranged at intervals along the tunnel axis, and each annular steel strip is connected to multiple axial steel strips. The multiple axial steel strips and multiple annular steel strips are interwoven and connected to form a cylindrical steel frame mesh.

[0014] Optionally, the tunnel energy-absorbing pressure support system further includes a protective net, which is installed on the steel frame net. The protective net includes multiple sets of single-cell hook-and-loop structures. The shape of the single-cell hook-and-loop structure is a concave negative Poisson's ratio cell shape. The structural endpoints of the single-cell hook-and-loop structure are connected to the shock-absorbing anchor rod.

[0015] Optionally, the tunnel pressure-absorbing support system further includes a locking anchor rod, one end of which is connected to the steel frame mesh, and the other end is used to pass through the flexible steel mesh and the flexible concrete spray layer and then anchor to the tunnel rock wall.

[0016] Compared with the prior art, the tunnel energy-absorbing pressure support system provided by the present invention has the following technical effects:

[0017] This invention provides initial rockburst protection for tunnel walls by covering them with a flexible concrete sprayed layer containing basalt confinement and coarse polypropylene fibers. This prevents cracking of the flexible concrete sprayed layer, improves material toughness and tensile / compressive strength, and provides primary rockburst protection. Furthermore, by covering the flexible concrete sprayed layer with a flexible steel mesh with a concave negative Poisson's ratio honeycomb structure, when a rockburst occurs, the flexible steel mesh is locally subjected to impact force. Its concave negative Poisson's ratio structure undergoes tensile and compressive stress, generating a certain amount of deformation and absorbing energy, making it less susceptible to damage and preventing rock fragments from being ejected. Simultaneously, by covering the flexible steel mesh with a steel frame mesh and connecting the steel frame mesh, flexible steel mesh, flexible concrete sprayed layer, and tunnel walls sequentially with shock-absorbing anchors, the steel frame mesh ensures overall structural strength while its mesh structure allows for a certain amount of deformation under stress, thus acting as a pressure relief mechanism. This prevents the entire structure from being solely rigid and unable to release pressure and force, which could lead to structural fracture and other failures. Moreover, by using shock-absorbing anchors… The anchor bolt is structured as a connector, rod, and sleeve. The connector is tightly pressed against the steel mesh, ensuring the overall structural stability. The sleeve is fitted onto the rod, and the two are elastically connected. When the anchor holes on the tunnel rock wall deform due to rock bursts or internal high stress, the sleeve abuts against the wall of the anchor hole outside the rod. The elastic connection between the sleeve and the rod buffers the impact of stress deformation on the structural strength of the rod, making the rod less susceptible to damage and providing a certain degree of energy absorption and vibration reduction. Furthermore, when the steel mesh, flexible steel mesh, and flexible concrete sprayed layer exert tensile or thrust stress on the shock-absorbing anchor bolt after deformation under stress, the elastic connection between the sleeve and the rod also provides a certain degree of energy absorption and vibration reduction. The friction between the sleeve and the wall of the anchor hole further prevents the rod from being pulled out and causing large displacement and failure, ensuring the stability and safety of the overall structure. Finally, the concrete layer completely covers the shock-absorbing anchor bolt, steel mesh, and flexible steel mesh, further ensuring the overall structural stability. Through the above structural design, this tunnel energy-absorbing and pressure-relief support system provides safe and stable support for the tunnel rock walls. Especially for rockbursts that may occur in high-stress tunnel rockburst sections, it absorbs energy through a step-by-step absorption of stress via flexible concrete spraying, flexible steel mesh, and shock-absorbing anchors. The steel frame mesh ensures structural strength while allowing pressure relief, and finally, a concrete layer provides complete coverage to ensure the stability of the overall structure. The overall energy-absorbing and pressure-relief system prevents damage to the overall structure from rockbursts, thereby ensuring the effectiveness of the support and improving safety.

[0018] In addition, the present invention also provides a tunnel energy-absorbing pressure support method, applicable to the above-mentioned tunnel energy-absorbing pressure support system, the method comprising the following steps:

[0019] A flexible concrete spray layer mixed with basalt fiber and coarse polypropylene fiber was sprayed onto the tunnel rock wall.

[0020] Anchor holes for anchoring and damping anchor rods were drilled in the tunnel rock wall;

[0021] A flexible steel mesh with a concave negative Poisson's ratio honeycomb structure is laid on the flexible concrete spray layer, and the positions of the anchoring holes are reserved in advance.

[0022] A steel frame mesh is erected on the surface of the flexible steel mesh, and the shock-absorbing anchor rod is passed through the steel frame mesh, the flexible steel mesh and the flexible concrete spray layer in sequence and then anchored in the anchor hole so that the steel frame mesh fits and presses the flexible steel mesh tightly;

[0023] A layer of concrete is sprayed onto the surface of the steel mesh to completely cover the steel mesh, the shock-absorbing anchors, the flexible steel mesh, and the flexible concrete spray layer.

[0024] The shock-absorbing anchor rod includes a rod body, a sleeve, and a connector. When installing the shock-absorbing anchor rod, the outer wall of the sleeve abuts against the wall of the anchoring hole, the rod body is anchored in the anchoring hole, the sleeve is fitted onto the rod body and elastically connected to the rod body, and the connector is connected to the end of the rod body away from the tunnel rock wall and pressed against the steel frame mesh.

[0025] Compared with the prior art, the tunnel energy-absorbing pressure support method provided by the present invention has roughly the same technical effect as the tunnel energy-absorbing pressure support system described above, and will not be repeated here. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the cross-sectional structure of the tunnel pressure-absorbing support system according to an embodiment of the present invention;

[0027] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0028] Figure 3 This is a schematic diagram of the cross-sectional structure of the shock-absorbing anchor rod according to an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the planar structure of the flexible steel mesh according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the shape of the concave negative Poisson's ratio cell in an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the planar structure of the tunnel pressure-absorbing support system according to an embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1-Flexible concrete spray layer, 2-Flexible steel mesh, 21-Mesh, 3-Steel frame mesh, 31-Axial steel strip, 32-Annular steel strip, 4-Concrete layer, 5-Shock-absorbing anchor, 51-Rod body, 52-Sleeve, 521-First sleeve, 522-Second sleeve, 53-Connector, 54-Elastic deformation component, 541-First elastic deformation component, 542-Second elastic deformation component, 55-Third spring, 56-First spring, 57-Second spring, 58-Fourth spring, 6-Tunnel rock wall, 61-Anchor hole, 7-Anchoring agent, 8-Unit cell chain structure, 9-Locking anchor. Detailed Implementation

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0035] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0036] In the description of this invention, the orientations or positional relationships indicated by terms such as "up," "down," "left," "right," "top," "bottom," "front," "back," "inner," and "outer" are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this disclosure. They are not intended to indicate or imply that the device referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this disclosure.

[0037] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] In the description of this specification, references to terms such as "embodiment," "one embodiment," and "one implementation" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or implementation is included in at least one embodiment or illustrative implementation of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or implementation. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or implementations.

[0039] To solve the above technical problems, such as Figures 1 to 3 As shown in the figure, this embodiment of the invention provides a tunnel pressure-absorbing support system, including a flexible concrete sprayed layer 1, a flexible steel mesh 2, a steel frame mesh 3, shock-absorbing anchors 5, and a concrete layer 4. The flexible concrete sprayed layer 1 is used to cover the tunnel rock wall 6. The flexible steel mesh 2 is used to cover the flexible concrete sprayed layer 1. The steel frame mesh 3 is used to cover the flexible steel mesh 2. The shock-absorbing anchors 5 pass through and connect the steel frame mesh 3, the flexible steel mesh 2, and the flexible concrete sprayed layer 1 in sequence, and are then anchored within the tunnel rock wall 6. The concrete layer 4 is used to cover the shock-absorbing anchors 5, the steel frame mesh 3, and the flexible concrete sprayed layer 1. The flexible steel mesh 2, the flexible concrete spray layer 1 is doped with basalt fiber and coarse polypropylene fiber, the flexible steel mesh 2 is a concave negative Poisson's ratio honeycomb mesh structure, the shock-absorbing anchor rod 5 includes a rod body 51, a sleeve 52 and a connector 53, the outer wall of the sleeve 52 is used to abut against the wall of the anchor hole 61 opened in the tunnel rock wall, the rod body 51 is used to anchor in the anchor hole 61, the sleeve 52 is sleeved on the rod body 51 and elastically connected to the rod body 51, the connector 53 is connected to the end of the rod body 51 away from the tunnel rock wall 6 and pressed onto the steel frame mesh 3.

[0040] It should be noted that, as Figure 4 As shown, the mesh 21 of the flexible steel mesh 2 has a concave negative Poisson's ratio structural cell shape (e.g., Figure 5 As shown, the structure composed of concave negative Poisson's ratio structural cells has certain concave negative Poisson's ratio structural characteristics. That is, when subjected to tension, its structure will expand and deform, and when subjected to pressure, its structure will compress and deform, which is called tensile-expansion-compression. This makes the structure composed of concave negative Poisson's ratio structural cells have a certain elastic deformation and is not easily damaged when subjected to external stress. In this embodiment, the flexible steel mesh 2 is woven with mesh 21 with concave negative Poisson's ratio structural cell shape. When encountering rockburst, the flexible steel mesh 2 is subjected to sudden tensile force, and its mesh 21 structure can deform to a certain extent. On the one hand, it prevents breakage and failure, and on the other hand, it can further prevent rock fragments from being ejected, which can effectively improve the stability and safety of use.

[0041] In addition, the flexible concrete spray layer 1 is mixed with basalt confinement and coarse polypropylene fiber and cement-based materials, which gives the flexible concrete spray layer 1 a certain amount of deformation, that is, a certain degree of flexibility. It is also easier to penetrate into cracks, such as those on the tunnel rock wall 6, making the surface structure of the tunnel rock wall 6 easier to connect into one and less prone to cracking.

[0042] Meanwhile, basalt confinement and coarse polypropylene fibers can also be mixed into concrete layer 4 with cement-based materials, which has the same beneficial effects as flexible concrete spray layer 1, and no specific limitations are made here.

[0043] In this embodiment, by covering the tunnel rock wall 6 with a flexible concrete sprayed layer 1 mixed with basalt confinement and coarse polypropylene fibers, cracking of the flexible concrete sprayed layer 1 is prevented, and the material toughness and tensile and compressive strength are improved, providing primary rockburst protection for the tunnel rock wall 6. Furthermore, by covering the flexible concrete sprayed layer 1 with a flexible steel mesh 2 having a concave negative Poisson's ratio honeycomb structure, when a rockburst occurs, the flexible steel mesh 2 is locally subjected to impact force, and its concave negative Poisson's ratio structure will generate a state of tensile and compressive expansion, producing a certain amount of deformation and energy absorption, making it less susceptible to damage and preventing rock bursts. The system is ejected, and simultaneously, a steel frame mesh 3 is laid on top of the flexible steel mesh 2. The steel frame mesh 3, flexible steel mesh 2, flexible concrete sprayed layer 1, and tunnel rock wall 6 are sequentially connected by shock-absorbing anchor rods 5. While ensuring the overall structural strength, the steel frame mesh 3's mesh structure allows for a certain amount of deformation under stress on the flexible steel mesh 2 or flexible concrete sprayed layer 1, thus playing a role in pressure relief. This prevents the entire structure from being entirely rigid under pressure, which could lead to structural fracture and other damage. Furthermore, by setting the shock-absorbing anchor rods 5 as connectors 53 and rods... The structural form of sleeve 51 and sleeve 52, with connector 53 tightly pressed against the steel mesh 3, ensures the connection stability of the overall structure. Sleeve 52 is fitted onto rod 51, and the two are elastically connected. When the anchor hole 61 on the tunnel rock wall 6 deforms due to rock bursts or internal high stress, sleeve 52 abuts against the wall of the anchor hole 61 outside the rod 51. The elastic connection between sleeve 52 and rod 51 can buffer the impact of stress deformation on the structural strength of rod 51, making rod 51 less prone to damage. It plays a certain role in energy absorption and shock absorption. Moreover, when the steel mesh 3, flexible... When the steel mesh 2 and the flexible concrete spray layer 1 generate a certain tensile or thrust stress on the shock-absorbing anchor rod 5 after deformation under stress, the elastic connection structure of the sleeve 52 and the rod 51 can also play a certain energy absorption and shock absorption effect. In addition, the sleeve 52 and the wall of the anchor hole 61 have a certain friction force, which further prevents the rod 51 from being pulled out and causing large displacement and failure, thus ensuring the stability and safety of the overall structure. Furthermore, the concrete layer 4 completely covers the shock-absorbing anchor rod 5, steel mesh 3 and flexible steel mesh 2, further ensuring the stability of the overall structure. Through the above structural design, this tunnel energy-absorbing and pressure-relief support system provides safe and stable support for the tunnel rock wall 6. Especially for rockbursts that may occur in high-stress tunnel rockburst sections, the system absorbs energy through the gradual absorption of stress by the flexible concrete spray layer 1, flexible steel mesh 2, and shock-absorbing anchors 5. The steel frame mesh 3 ensures structural strength while allowing pressure relief. Finally, the concrete layer 4 provides complete coverage to ensure the stability of the overall structure. The overall energy-absorbing and pressure-relief system prevents damage to the overall structure from rockbursts, thereby ensuring the effectiveness of the support and improving safety.

[0044] Optionally, such as Figure 3As shown, the shock-absorbing anchor rod 5 also includes an elastic deformation member 54, which is sleeved on the rod body 51 and connected to the end of the sleeve 52.

[0045] Specifically, the elastic deformation member 54 can also be threadedly connected to the rod body 51. During installation, the rod body 51 can be screwed through the elastic deformation member 54, making the structure more stable and robust. The elastic deformation member 54 can be made of rubber, plastic or other materials with elastic deformation characteristics, and its contour shape matches the end of the sleeve 52.

[0046] In this embodiment, by providing the elastic deformation member 54, the stress transmission between the sleeve 52 and the rod 51 can be further buffered, making the rod 51 less susceptible to damage and further improving the overall energy absorption effect of the structure.

[0047] Optionally, such as Figure 3 As shown, the shock-absorbing anchor rod 5 further includes a third spring 55, the sleeve 52 includes a first sleeve 521 and a second sleeve 522 respectively sleeved on the rod body 51, the elastic deformation member 54 includes a first elastic deformation member 541 and a second elastic deformation member 542, the first elastic deformation member 541 is connected to the end of the first sleeve 521 near the second sleeve 522, the second elastic deformation member 542 is connected to the end of the second sleeve 522 near the first sleeve 521, and the third spring 55 is sleeved on the rod body 51 and connected between the first elastic deformation member 541 and the second elastic deformation member 542.

[0048] Specifically, a first elastic deformation member 541 can be provided at both ends of the first sleeve 521, and correspondingly, a second elastic deformation member 542 can be provided at both ends of the second sleeve 522. The first sleeve 521 and the second sleeve 522 can have the same structure for easy processing, and the first elastic deformation member 541 and the second elastic deformation member 542 can also have the same structure.

[0049] In this embodiment, by setting the sleeve 52 as a first sleeve 521 and a second sleeve 522, setting the elastic deformation member 54 as a first elastic deformation member 541 and a second elastic deformation member 542, and setting a third spring 55 between them, when the rod 51 is subjected to external stress, the first sleeve 521 and the second sleeve 522 can carry out graded stress transmission and absorb energy step by step under the connection of the third spring 55 between them. This has a better absorption effect on the impact force on the rod 51 when rockburst occurs, and further improves the stability and safety of the overall structure.

[0050] Optionally, such as Figure 3As shown, the shock-absorbing anchor rod 5 also includes a first spring 56 and a second spring 57 respectively sleeved on the rod body 51. The first spring 56 is placed inside the first sleeve 521, and one end of it is connected to the rod body 51, and the other end is connected to the first elastic deformation member 541. The second spring 57 is placed inside the second sleeve 522, and one end of it is connected to the rod body 51, and the other end is connected to the second elastic deformation member 542.

[0051] Specifically, the first spring 56 and the second spring 57 can have the same structure. When both ends of the first sleeve 521 are provided with the first elastic deformation member 541, both ends of the first spring 56 can be connected and fixed with the first elastic deformation member 541. Similarly, the second spring 57 can also be matched with this structure.

[0052] In this embodiment, by setting a first spring 56 and a second spring 57 in the first sleeve 521 and the second sleeve 522 respectively, the graded resistance-increasing energy absorption effect of the shock-absorbing anchor rod 5 is further enhanced. That is, when a rockburst occurs, the rod body 51 is subjected to an impact force (basically a tension force on the shock-absorbing anchor rod 5). The first spring 56 undergoes elastic deformation. When the deformation reaches a certain level, the stress is transmitted to the third spring 55 through the first elastic deformation member 541. After the third spring 55 absorbs energy through deformation, if there is still additional stress, it is transmitted to the second spring 57 through the second elastic deformation member 542 for further elastic deformation and energy absorption. This achieves graded force release and energy absorption, protecting the rod body from damage. At the same time, the first elastic deformation member 541 and the second elastic deformation member 542 can transmit stress to the first sleeve 521 and the second sleeve 522. Both the first sleeve 521 and the second sleeve 522 abut against the wall of the anchor hole 61, generating friction and increasing resistance, further preventing the rod body 51 from undergoing large deformation and displacement.

[0053] Optionally, such as Figure 3 As shown, the ends of the first sleeve 521 and the second sleeve 522 near the bottom of the anchoring hole 61 are both configured as wedge-shaped structures.

[0054] In this example, by setting the ends of the first sleeve 521 and the second sleeve 522 near the bottom of the anchor hole 61 as wedge-shaped structures, the first sleeve 521 and the second sleeve 522 are more convenient and easier to insert into the anchor hole 61 when the shock-absorbing anchor rod 5 is installed, which facilitates installation.

[0055] Optionally, such as Figure 3 As shown, the rod body 51 includes a continuously arranged connecting section, a main body section and an anchoring section. The connecting section is connected to the connector 53. The anchoring section is used to anchor to the bottom of the anchoring hole 61. The structural cell constituting the main body section is a concave negative Poisson's ratio structural cell.

[0056] Specifically, the connector 53 is a nut, and the connecting section has an external thread that matches it, which facilitates connection, installation and disassembly. The structure of the connecting section and the anchoring section can also be composed of concave negative Poisson's ratio structural cells.

[0057] In this embodiment, by setting the cylinder 51 into a continuous connecting section, main body section, and anchoring section, the connecting section facilitates connection and installation with the connector 53, and the anchoring section facilitates overall anchoring. Furthermore, by setting the structural cell of the main body section as a concave negative Poisson's ratio structural cell, the main body of the rod 51 has the characteristics of a concave negative Poisson's ratio structure. That is, when the rod 51 is stretched, its structure will expand and deform; when it is compressed, its structure will compress and deform. This is called tensile expansion and compression, which makes the main body section composed of concave negative Poisson's ratio structural cells have a certain elastic deformation. It is not easily damaged when subjected to external stress, and at the same time, it can further absorb energy, making the structure of the shock-absorbing anchor rod 5 more stable and its energy absorption effect further improved.

[0058] Optionally, such as Figure 3 As shown, the tunnel pressure-absorbing support system also includes an anchoring agent 7. The end of the anchoring section is a wedge-shaped structure and the anchoring section is provided with external threads. The anchoring agent 7 is used to be placed at the bottom of the anchoring hole 61, and the anchoring section is anchored to the anchoring agent 7.

[0059] Specifically, when installing the shock-absorbing anchor rod 5, the anchoring agent 7 can be pre-inserted into the bottom of the anchor hole 61. The anchoring agent 7 is used to enhance the firmness of the anchoring structure.

[0060] In this embodiment, by setting the anchoring agent 7 at the bottom of the anchoring hole 61 and anchoring the anchoring section in the anchoring agent 7, the structural robustness of the shock-absorbing anchor rod 5 is further enhanced. By setting the end of the anchoring section as a wedge-shaped structure, it is easy to insert into the anchoring hole 61 and the anchoring agent 7, which facilitates installation. Furthermore, by setting external threads on the anchoring section, on the one hand, the rod body 51 can be screwed into the anchoring hole 61 and the anchoring agent 7 during installation, and on the other hand, the friction between the anchoring section and the anchoring agent 7 is increased, making the rod body 51 less likely to be pulled out and fail, thereby improving the overall structural stability.

[0061] Optionally, such as Figure 3 As shown, the shock-absorbing anchor rod 5 also includes a fourth spring 58, which is sleeved on the connecting section and its two ends abut against the connecting member 53 and the steel frame mesh 3 respectively.

[0062] Specifically, a constraint steel ring is also provided on the fourth spring 58 to restrict the structural position of the fourth spring 58, so that it is stably connected between the connector 53 and the steel frame mesh 3.

[0063] In this embodiment, by setting a fourth spring 58 between the connector 53 and the steel frame mesh 3, a shock-absorbing and buffering effect can be further achieved. While absorbing energy under further stress, it prevents the steel frame mesh 3 from deforming and causing the connection between it and the shock-absorbing anchor rod 5 to fail, thereby further improving the stability of the overall structure and the safety of use.

[0064] Optionally, such as Figure 6 As shown, the steel frame mesh 3 includes axial steel strips 31 and annular steel strips 32. The axial steel strips 31 are arranged along the tunnel axis, and multiple axial steel strips 31 are spaced apart. Multiple annular steel strips 32 are arranged along the tunnel axis, and each annular steel strip 32 is connected to multiple axial steel strips 31. The multiple axial steel strips 31 and multiple annular steel strips 32 are interwoven to form the steel frame mesh 3.

[0065] Specifically, the axial steel strip 31 can be an axial narrow steel strip or an axial wide steel strip. The number of axial narrow steel strips and the spacing between them are selected according to the actual application. They are combined and woven in a staggered mesh structure. For example, two adjacent axial steel strips 31 are located on opposite sides of the annular steel strip 32, and so on, and are staggered. The axial narrow steel strips and axial wide steel strips are connected by welding at the intersection with the annular steel strip 32. At the intersection, the axial narrow steel strip, axial wide steel strip or annular steel strip 32 is bent to better fit the flexible steel mesh 2, making the overall structure more stable.

[0066] In this embodiment, by setting axial steel strips 31 and annular steel strips 32, and interweaving multiple axial steel strips 31 and multiple annular steel strips 32 to form a steel frame mesh 3, on the one hand, the flexible steel mesh 2 can be pressed more tightly to transfer stress and bear load; on the other hand, it provides rigid support to the overall structure and prevents structural deformation and failure.

[0067] Optionally, such as Figure 6 As shown, the tunnel energy absorption and pressure support system also includes a protective net, which is set on the steel frame net 3. The protective net includes multiple sets of single-cell hook-and-loop structures 8. The shape of the single-cell hook-and-loop structure 8 is a concave negative Poisson's ratio cell shape. The structural endpoints of the single-cell hook-and-loop structure 8 are connected to the shock-absorbing anchor rod.

[0068] Specifically, the single-cell chain structure 8 may have steel wire ropes or reinforcing bars connected to pre-positioned shock-absorbing anchor rods 5, thereby forming a concave negative Poisson's ratio cell shape (such as...). Figure 5 As shown), and the multiple sets of single-cell chain structures 8 can be independent of each other or connected to each other. The shock-absorbing anchor rods 5 used to connect steel wire ropes or steel bars to form the single-cell chain structure can be pre-installed.

[0069] In this embodiment, by setting a protective net on the steel frame mesh 3, the tunnel rock wall 6 can be further protected. Furthermore, by making the protective net consist of multiple sets of single-cell hook-and-loop structures 8, and setting the shape of the single-cell hook-and-loop structure 8 to a concave negative Poisson's ratio cell shape, the concave negative Poisson's ratio structure can further improve the overall toughness and stress absorption effect, thereby improving the overall structural stability and rockburst prevention capability.

[0070] Optionally, such as Figure 1 and Figure 2 As shown, the tunnel pressure-absorbing support system also includes a locking anchor rod 9. One end of the locking anchor rod 9 is connected to the steel frame mesh 3, and the other end is used to pass through the flexible steel mesh 2 and the flexible concrete spraying layer 1 and then anchor to the tunnel rock wall 6.

[0071] Specifically, the anchor bolt 9 can be connected to the axial steel strip 31 and / or the annular steel strip 32 of the steel frame mesh 3.

[0072] In this embodiment, by setting the locking anchor rod 9 and connecting it to the steel frame mesh 3, and then anchoring it to the tunnel rock wall 6 after passing through the flexible steel mesh 2 and the flexible concrete spray layer 1, the overall structural strength is further improved. On the other hand, the locking anchor rod 9 can also serve as the connection fulcrum of the structural endpoint of the single-cell hook structure 8, improving the overall structure and the convenience of installation.

[0073] In addition, another embodiment of the present invention provides a tunnel energy-absorbing pressure support method, applicable to the above-mentioned tunnel energy-absorbing pressure support system, the method comprising the following steps:

[0074] A flexible concrete spray layer 1, mixed with basalt fiber and coarse polypropylene fiber, was sprayed onto the tunnel rock wall 6.

[0075] Anchor holes 61 are drilled in the tunnel rock wall 6 for anchoring and damping anchor rods 5;

[0076] A flexible steel mesh 2 with a concave negative Poisson's ratio honeycomb structure is laid on the flexible concrete spray layer 1, and the position of the anchor hole 61 is reserved.

[0077] A steel frame mesh 3 is erected on the surface of the flexible steel mesh 2, and the shock-absorbing anchor rod 5 is sequentially passed through the steel frame mesh 3, the flexible steel mesh 2 and the flexible concrete spray layer 1 and then anchored in the anchor hole 61, so that the steel frame mesh 3 fits and presses the flexible steel mesh 2 tightly.

[0078] A concrete layer 4 is sprayed onto the surface of the steel mesh 3 so that the concrete layer 4 completely covers the steel mesh 3, the shock-absorbing anchor rod 5, the flexible steel mesh 2, and the flexible concrete spray layer 1;

[0079] The shock-absorbing anchor rod 5 includes a rod body 51, a sleeve 52, and a connector 53. When installing the shock-absorbing anchor rod 5, the outer wall of the sleeve 52 abuts against the wall of the anchor hole 61, the rod body 51 is anchored in the anchor hole 61, the sleeve 52 is sleeved on the rod body 51 and elastically connected to the rod body 51, and the connector 53 is connected to the end of the rod body 51 away from the tunnel rock wall 6 and pressed against the steel frame mesh 3.

[0080] In this embodiment, the tunnel pressure-absorbing support method has roughly the same technical effect as the tunnel pressure-absorbing support system in the above embodiments, and will not be described again here.

[0081] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the scope of protection of this invention.

Claims

1. A tunnel pressure-absorbing support system, characterized in that, The system includes a flexible concrete spray layer (1), a flexible steel mesh (2), a steel frame mesh (3), shock-absorbing anchors (5), and a concrete layer (4). The flexible concrete spray layer (1) is used to cover the tunnel rock wall (6). The flexible steel mesh (2) is placed over the flexible concrete spray layer (1). The steel frame mesh (3) is placed over the flexible steel mesh (2). The shock-absorbing anchors (5) pass through and connect the steel frame mesh (3), the flexible steel mesh (2), and the flexible concrete spray layer (1) in sequence, and are then anchored within the tunnel rock wall (6). The concrete layer (4) is placed over the shock-absorbing anchors (5), the steel frame mesh (3), and the flexible steel mesh (2). The flexible concrete spray layer (1) is doped with basalt fiber and coarse polypropylene fiber. The flexible steel mesh (2) is a concave negative Poisson's ratio honeycomb mesh structure. The shock-absorbing anchor rod (5) includes a rod body (51), a sleeve (52) and a connector (53). The outer wall of the sleeve (52) is used to abut against the wall of the anchor hole (61) opened in the tunnel rock wall. The rod body (51) is used to anchor in the anchor hole (61). The sleeve (52) is sleeved on the rod body (51) and elastically connected to the rod body (51). The connector (53) is connected to the end of the rod body (51) away from the tunnel rock wall (6) and pressed onto the steel mesh (3). The shock-absorbing anchor rod (5) also includes an elastic deformation member (54), which is sleeved on the rod body (51) and connected to the end of the sleeve (52); The shock-absorbing anchor rod (5) also includes a third spring (55). The sleeve (52) includes a first sleeve (521) and a second sleeve (522) respectively sleeved on the rod body (51). The elastic deformation member (54) includes a first elastic deformation member (541) and a second elastic deformation member (542). The first elastic deformation member (541) is connected to the end of the first sleeve (521) near the second sleeve (522). The second elastic deformation member (542) is connected to the end of the second sleeve (522) near the first sleeve (521). The third spring (55) is sleeved on the rod body (51) and connected between the first elastic deformation member (541) and the second elastic deformation member (542).

2. The tunnel pressure-absorbing support system according to claim 1, characterized in that, The ends of the first sleeve (521) and the second sleeve (522) near the bottom of the anchor hole (61) are both configured as wedge-shaped structures.

3. The tunnel pressure-absorbing support system according to claim 1, characterized in that, The shock-absorbing anchor rod (5) also includes a first spring (56) and a second spring (57) respectively sleeved on the rod body (51). The first spring (56) is placed inside the first sleeve (521), and one end of it is connected to the rod body (51) and the other end is connected to the first elastic deformation member (541). The second spring (57) is placed inside the second sleeve (522), and one end of it is connected to the rod body (51) and the other end is connected to the second elastic deformation member (542).

4. The tunnel pressure-absorbing support system according to claim 1, characterized in that, The rod (51) includes a continuously arranged connecting section, a main body section and an anchoring section. The connecting section is connected to the connector (53). The anchoring section is used to anchor to the bottom of the anchoring hole (61). The structural cell of the main body section is a concave negative Poisson's ratio structural cell.

5. The tunnel pressure-absorbing support system according to claim 4, characterized in that, It also includes an anchoring agent (7), the end of the anchoring section is a wedge-shaped structure, and the anchoring section is provided with external threads. The anchoring agent (7) is used to be placed at the bottom of the anchoring hole (61), and the anchoring section is anchored to the anchoring agent (7).

6. The tunnel pressure-absorbing support system according to claim 4, characterized in that, The shock-absorbing anchor rod (5) also includes a fourth spring (58), which is sleeved on the connecting section and its two ends abut against the connecting piece (53) and the steel frame mesh (3) respectively.

7. The tunnel pressure-absorbing support system according to claim 1, characterized in that, The steel frame mesh (3) includes axial steel strips (31) and annular steel strips (32). The axial steel strips (31) are arranged along the tunnel axis, and multiple axial steel strips (31) are spaced apart. Multiple annular steel strips (32) are arranged along the tunnel axis, and each annular steel strip (32) is connected to multiple axial steel strips (31). The multiple axial steel strips (31) and multiple annular steel strips (32) are interwoven to form the steel frame mesh (3).

8. The tunnel pressure-absorbing support system according to claim 1, characterized in that, It also includes a protective net, which is set on the steel frame net (3). The protective net includes multiple sets of single-cell hook-and-loop structures (8). The shape of the single-cell hook-and-loop structure (8) is a concave negative Poisson's ratio cell shape. The structural endpoints of the single-cell hook-and-loop structure (8) are connected to the shock-absorbing anchor rod.

9. The tunnel pressure-absorbing support system according to claim 1, characterized in that, It also includes a foot anchor (9), one end of which is connected to the steel frame mesh (3), and the other end is used to pass through the flexible steel mesh (2) and the flexible concrete spray layer (1) and then anchor to the tunnel rock wall (6).

10. A tunnel pressure-absorbing support method, applicable to the tunnel pressure-absorbing support system as described in any one of claims 1 to 9, characterized in that, The method includes the following steps: A flexible concrete spray layer (1) mixed with basalt fiber and coarse polypropylene fiber was sprayed onto the tunnel rock wall (6). Anchor holes (61) are drilled in the tunnel rock wall (6) for anchoring and damping anchor rods (5). A flexible steel mesh (2) with a concave negative Poisson's ratio honeycomb structure is laid on the flexible concrete spray layer (1), and the position of the anchor hole (61) is reserved. A steel frame mesh (3) is erected on the surface of the flexible steel mesh (2), and the shock-absorbing anchor rod (5) is passed through the steel frame mesh (3), the flexible steel mesh (2) and the flexible concrete spray layer (1) in sequence and then anchored in the anchor hole (61) so that the steel frame mesh (3) fits and presses the flexible steel mesh (2). A concrete layer (4) is sprayed onto the surface of the steel mesh (3) so that the concrete layer (4) completely covers the steel mesh (3), the shock-absorbing anchor (5), the flexible steel mesh (2) and the flexible concrete spray layer (1). The shock-absorbing anchor rod (5) includes a rod body (51), a sleeve (52), and a connector (53). When installing the shock-absorbing anchor rod (5), the outer wall of the sleeve (52) abuts against the wall of the anchor hole (61). The rod body (51) is anchored in the anchor hole (61). The sleeve (52) is fitted onto the rod body (51) and is elastically connected to the rod body (51). The connector (53) is connected to the end of the rod body (51) away from the tunnel rock wall (6) and is pressed onto the steel frame mesh (3).

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