Bionic negative poisson's ratio multi-stage energy-absorbing anchor rod and construction method thereof

Abstract

The application provides a bionic negative Poisson's ratio multi-stage energy absorption anchor rod and a construction method thereof, and belongs to the field of tunnel construction and underground engineering. The bionic negative Poisson's ratio multi-stage energy absorption anchor rod comprises an energy absorption anchor head assembly, a hierarchical energy absorption rod body assembly and a terminal anchoring rod assembly. The energy absorption anchor head assembly comprises an end connecting rod, an end energy absorption sleeve and a bionic negative Poisson's ratio energy absorption component. The hierarchical energy absorption rod body assembly comprises a pressure-relief push rod, an energy absorption sleeve and a bionic negative Poisson's ratio energy absorption component. The hollow end connecting rod, the pressure-relief push rod and the terminal connecting rod are sequentially connected to form an internal grouting channel. The bionic negative Poisson's ratio energy absorption component is adopted in the application, combined with the hierarchical energy absorption sleeve and the pressure-relief push rod, to realize multi-stage energy absorption of 'elastic buffering + plastic deformation + bionic structure energy consumption', which can adapt to impact loads of different intensities. Meanwhile, the internal grouting channel is used to realize full-hole grouting, fill the surrounding rock gap and form a corrosion-resistant layer, and the anchoring and corrosion-resistant requirements are considered.

Description

Technical Field

[0001] This application relates to the field of underground engineering in tunnel construction, specifically to a biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor and its construction method. Background Technology

[0002] As mining depth increases, geological conditions in deeper areas change significantly. Under high ground stress, the failure mechanism of the surrounding rock changes, often leading to large deformations, spalling, rock bursts, and other phenomena in the roadway. Mining pressure becomes severe, and in serious cases, it can cause anchor bolts to break, resulting in the failure of the existing roadway support system.

[0003] Currently, conventional support materials such as left-hand threaded steel anchors, commonly used in mine roadways, are insufficient to meet the long-term stability requirements of deep mine roadways due to their poor ductility and weak impact resistance. Although many experts and scholars have proposed new solutions such as pressure-yielding anchors, high-damping energy-absorbing anchors, and energy-absorbing anchor rings, existing technologies generally suffer from problems such as short pressure-yielding distances and cumbersome installation procedures.

[0004] Patent document CN112983520B discloses a multi-stage pressure-yielding anchor bolt suitable for supporting tunnels with large deformation in soft rock. It includes an end anchoring section member and a pressure-yielding mechanism positioned above the end anchoring section member for pressure yielding. The pressure yielding distance is adjusted by increasing or decreasing the number of intermediate pressure-yielding components. Pressure yielding is achieved through the instability deformation of a thin-walled metal cylinder, and axial force is monitored by a ring pressure sensor. This structure relies on the instability deformation of the thin-walled metal cylinder. Although it can be combined in multiple stages, its energy absorption method is limited to the plastic deformation of the metal structure, making it prone to failure due to cumulative damage under high-frequency, strong impact loads.

[0005] Patent document CN114941544B discloses a dual energy-absorbing anchor bolt and support method, including a main rod body, an auxiliary rod body, a primary energy-absorbing mechanism (spring, baffle, sensor) and a secondary energy-absorbing mechanism (conical rod body, expansion sleeve). Primary energy absorption is achieved through spring compression, and secondary energy absorption is achieved through plastic deformation of the expansion sleeve. However, the spring has a low elastic limit, and after the primary energy absorption fails, it relies solely on the expansion sleeve mechanism, which is difficult to cope with continuous deformation under complex geological conditions. Summary of the Invention

[0006] In view of the technical problems existing in the background art, and considering the characteristics of large deformation and strong disturbance in deep mine roadways, this invention provides a biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor bolt and its construction method, which can absorb strong impact energy in stages, provide constant resistance, and allow appropriate deformation of the surrounding rock, so as to ensure safe production in mines.

[0007] The energy-absorbing anchor bolt of this application adopts a biomimetic negative Poisson's ratio energy-absorbing component (tortoise shell biomimetic structure), combined with a graded energy-absorbing sleeve and a pressure-relief push rod, to achieve multi-stage energy absorption of "elastic buffering + plastic deformation + biomimetic structure energy dissipation", which can adapt to impact loads of different intensities; at the same time, this application utilizes a hollow rod body to integrate a grouting channel, and achieves full-hole grouting through the grouting channel to fill the voids in the surrounding rock and form an anti-corrosion layer, taking into account both anchoring and anti-corrosion requirements.

[0008] This application can also precisely set the yielding axial force threshold by changing the unit thickness, size and number of the biomimetic negative Poisson's ratio component, thus solving the problem that the yielding threshold is difficult to adjust flexibly in the prior art.

[0009] In a first aspect, embodiments of this application provide a biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor bolt, including an energy-absorbing anchor head assembly, comprising a hollow end connecting rod and a limiting tray, an end energy-absorbing sleeve, a tray, and an annular pressure sensor sequentially sleeved on the end connecting rod; a biomimetic negative Poisson's ratio energy-absorbing component is disposed within the receiving space formed by the end energy-absorbing sleeve and the outer peripheral wall of the end connecting rod; the upper end of the end connecting rod is provided with an external thread adapted to a nut;

[0010] A tiered energy-absorbing rod assembly includes at least two energy-absorbing components; each energy-absorbing component includes a hollow pressure-relief push rod, an energy-absorbing sleeve sleeved around the outer periphery of the pressure-relief push rod, and a biomimetic negative Poisson's ratio energy-absorbing member disposed within a receiving space formed by the outer periphery of the energy-absorbing sleeve and the pressure-relief push rod; the uppermost energy-absorbing sleeve is connected to the lower end of the end connecting rod, and the bottom of the pressure-relief push rod is connected to the energy-absorbing sleeve or end anchoring member of the next-level energy-absorbing component;

[0011] The end anchoring rod assembly includes a hollow end connecting rod and a stirring structure connected to the end connecting rod; the end connecting rod has a slurry outlet on its peripheral wall;

[0012] The end connecting rod, the pressure-relieving push rod, and the end connecting rod are connected in sequence to form an internal grouting channel.

[0013] Furthermore, the biomimetic negative Poisson's ratio energy-absorbing component adopts a tortoise shell biomimetic structure. The biomimetic negative Poisson's ratio energy-absorbing component includes several vertical repeating units and connecting horizontal plates connecting adjacent vertical repeating units. Each vertical repeating unit includes several minimum repeating units. Each minimum repeating unit includes an upper plate and a lower plate arranged opposite each other, as well as two oppositely arranged inwardly concave arc-shaped plates connecting the upper plate and the lower plate.

[0014] Furthermore, the vertical repeating unit is arranged in a multi-layered structure with gradually varying sizes; from top to bottom, the thickness of the upper plate, lower plate, arc plate, and connecting horizontal plate connected to the arc plate of the smallest repeating unit increases in a gradient.

[0015] Furthermore, the upper plate, lower plate, arc plate, and connecting horizontal plate of the same minimum repeating unit have the same thickness; the thickness difference between adjacent minimum repeating units in the same vertical repeating unit is 0.2-0.3 mm.

[0016] Furthermore, the upper plate, lower plate, arc plate, and connecting cross plate connected to the arc plate of the same minimum repeating unit have the same thickness; the thickness range is 0.5-12mm.

[0017] Furthermore, the outer diameter of the biomimetic negative Poisson's ratio energy-absorbing component is the same as the inner diameter of the energy-absorbing sleeve and the end energy-absorbing sleeve.

[0018] Furthermore, the biomimetic negative Poisson's ratio energy-absorbing component is integrally molded.

[0019] Furthermore, the pressure-relief push rod includes a hollow disc structure at the upper end and a hollow rod-shaped structure at the lower end; the outer diameter of the hollow disc structure is the same as the inner diameter of the energy-absorbing sleeve; the central axes of the end connecting rod, the end energy-absorbing sleeve, the pressure-relief push rod, the energy-absorbing sleeve, and the end connecting rod are collinear.

[0020] Furthermore, the stirring structure is a foldable end fin.

[0021] Secondly, embodiments of this application provide a construction method for a biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor bolt, used for constructing the biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor bolt described in any of the aforementioned technical solutions; including the following steps:

[0022] S1, using an anchor drilling rig to drill holes on the surface of the surrounding rock of the roadway that needs support, according to the predetermined position and hole depth, to drill surrounding rock holes that match the diameter of the biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor.

[0023] S2, the resin anchoring agent is placed into the depth of the borehole, and the hollow end connecting rod, the graded energy-absorbing rod assembly, and the end anchoring rod assembly are assembled according to the borehole depth. The stirring structure at the end is opened, the biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor is inserted into the borehole, and the anchor drilling machine is started. The stirring structure at the end is used to fully stir the resin anchoring agent and push it to the bottom of the borehole before stopping. The anchor drilling machine is then removed. The graded energy-absorbing rod assembly includes at least two energy-absorbing components. Each energy-absorbing component includes a hollow pressure-relief push rod, an energy-absorbing sleeve sleeved around the pressure-relief push rod, and a biomimetic negative Poisson's ratio energy-absorbing component disposed in the receiving space formed by the outer peripheral wall of the energy-absorbing sleeve and the pressure-relief push rod. The uppermost energy-absorbing sleeve is connected to the lower end of the end connecting rod, and the bottom of the pressure-relief push rod is connected to the energy-absorbing sleeve or end anchoring rod of the next stage energy-absorbing component.

[0024] S3, the limiting tray, end energy-absorbing sleeve, tray and annular pressure sensor are sequentially mounted on the end connecting rod, and the nut is screwed on the outer end of the end connecting rod. The torque is applied to the nut to complete the anchor bolt pre-tightening support.

[0025] S4. After the resin anchoring agent has bonded, the anchor rod body is tensioned using a tensioning tool to achieve the predetermined locking force, so that the anchor rod is in a tensioned state. The tension force must be lower than the axial force threshold of the energy-absorbing sleeve of the graded energy-absorbing rod assembly when it is under pressure.

[0026] S5. Regularly observe the deformation of the surrounding rock in the roadway. When the displacement of the anchor bolt reaches the displacement limit of the pressure pusher or encounters an impact, grout the anchor bolt through the internal grouting channel formed by the end connecting rod, the pressure pusher, and the end connecting rod to achieve full bonding and anchoring of the anchor bolt.

[0027] The beneficial effects of this invention are:

[0028] In the technical solution of this application embodiment, a biomimetic negative Poisson's ratio energy-absorbing component is adopted, which provides constant resistance while absorbing energy in stages, effectively controlling the deformation of the surrounding rock of the roadway, resisting strong impacts, ensuring the safety of personnel and equipment in the roadway, and realizing safe production in the mine.

[0029] Specifically, the push rod compresses the biomimetic negative Poisson's ratio energy-absorbing component under tensile load, and the load is distributed to the roadway surface through the cooperation of the end energy-absorbing sleeve and the limiting tray. Within the staged energy-absorbing rod body, the push rod slides along the sleeve axis, generating a certain pressure relief distance and providing constant resistance, effectively improving the elongation rate of the anchor bolt. The internal energy-absorbing component absorbs energy through deformation, preventing the anchor bolt from breaking during large deformations of the surrounding rock or rock bursts. Furthermore, this application utilizes a hollow rod body to integrate internal grouting channels, achieving full-hole grouting through these channels to fill the voids in the surrounding rock and form an anti-corrosion layer, thus addressing both anchoring and corrosion protection requirements.

[0030] This application adopts a segmented energy-absorbing component (multi-stage pressure-relief structure) with a modular design. The pressure-relief distance and anchor length can be flexibly increased by changing the number of staged energy-absorbing rods to achieve anchoring of surrounding rock in roadways at different depths.

[0031] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0032] To more clearly illustrate the technical solution of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of the biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor provided in the embodiments of this application.

[0034] Figure 2 This is a schematic cross-sectional view of the biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor provided in the embodiments of this application.

[0035] Figure 3 This is a schematic diagram of the energy-absorbing anchor head assembly.

[0036] Figure 4 This is a schematic diagram of the energy absorption component.

[0037] Figure 5 This is a structural schematic diagram of the end anchoring rod assembly.

[0038] Figure 6 A schematic diagram of the pressure relief working state of the energy absorption component.

[0039] Figure 7 This is a schematic diagram of one embodiment of the biomimetic negative Poisson's ratio energy-absorbing component of the present invention.

[0040] Figure 8 This is a schematic diagram of another embodiment of the biomimetic negative Poisson's ratio energy-absorbing component of the present invention. Detailed Implementation

[0041] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0043] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0044] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0045] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two). In the description of the embodiments of this application, the technical terms "top," "bottom," "upper," "lower," "inner," "horizontal," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying 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 limitations on the embodiments of this application.

[0046] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0047] In the description of the embodiments of this application, anchor bolt drilling refers to forming a hole of a specific diameter and depth in the surrounding rock of a roadway by means of drilling or other methods to meet the installation space requirements for installing anchor bolts. In the description of this invention, the term "top" refers to the section of the anchor bolt or component near the anchor bolt hole opening; "bottom" refers to the section of the anchor bolt or component near the bottom of the anchor bolt hole.

[0048] Please see Figures 1 to 8 As shown, this application provides a biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor bolt, including an energy-absorbing anchor head assembly, a staged energy-absorbing rod body assembly, and an end anchoring rod assembly. The energy-absorbing anchor head assembly includes a hollow end connecting rod 6 and a limiting tray 5, an end energy-absorbing sleeve 4, a tray 3, and an annular pressure sensor 2 sequentially sleeved on the end connecting rod 6.

[0049] A biomimetic negative Poisson's ratio energy-absorbing component 13 is installed within the receiving space formed by the outer peripheral wall of the end energy-absorbing sleeve 4 and the end connecting rod 6. The upper end of the end connecting rod 6 is provided with an external thread that is compatible with the nut 1.

[0050] The end energy-absorbing sleeve 4 is a short, straight cylindrical metal tube made of high-strength steel.

[0051] The ring pressure sensor 2 adopts a piezoelectric pressure sensor, which can realize on-site monitoring and calibration of anchoring force and can monitor the stress of the anchor rod throughout its entire life cycle in real time.

[0052] The bottom of the end connecting rod 6 is connected to the graded energy-absorbing rod assembly.

[0053] The graded energy-absorbing rod assembly includes at least two energy-absorbing components. Each energy-absorbing component includes a hollow pressure-relief push rod 8, an energy-absorbing sleeve 7 sleeved around the outer periphery of the pressure-relief push rod 8, and a biomimetic negative Poisson's ratio energy-absorbing member 13 disposed within the receiving space formed by the outer periphery of the energy-absorbing sleeve 7 and the pressure-relief push rod 8. The uppermost energy-absorbing sleeve 7 is connected to the lower end of the end connecting rod 6, and the bottom of the pressure-relief push rod 8 is connected to the energy-absorbing sleeve 7 or the end anchoring rod of the next stage energy-absorbing component.

[0054] In this embodiment, the graded energy-absorbing rod assembly includes two energy-absorbing components, namely a first energy-absorbing component and a second energy-absorbing component. The energy-absorbing sleeve 7 of the first energy-absorbing component is connected to the bottom of the end connecting rod 6.

[0055] It should be understood that the number of energy-absorbing components can be set according to actual application requirements.

[0056] The energy-absorbing sleeve 7 includes a cylindrical main body 71 and a cylindrical boss 72 protruding upward from the main body 71; the outer diameter of the cylindrical boss 72 is smaller than the outer diameter of the main body 71. The inner peripheral wall of the cylindrical boss 72 is provided with an internal thread that matches the external thread of the lower end of the end connecting rod 6, for connecting the energy-absorbing sleeve 7 and the end connecting rod 6.

[0057] The energy-absorbing sleeve 7 is made of high-strength steel.

[0058] In some embodiments, the biomimetic negative Poisson's ratio energy-absorbing component 13 adopts a tortoise shell biomimetic structure.

[0059] The biomimetic negative Poisson's ratio energy-absorbing component 13 is integrally molded. The outer diameter of the biomimetic negative Poisson's ratio energy-absorbing component 13 is the same as the inner diameter of the energy-absorbing sleeve 7 and the end energy-absorbing sleeve 4.

[0060] Please see Figures 7 to 8As shown, the biomimetic negative Poisson's ratio energy-absorbing component 13 includes several vertical repeating units and connecting horizontal plates 132 connecting adjacent vertical repeating units. Each vertical repeating unit includes several minimum repeating units 131. The minimum repeating unit 131 includes an upper plate 133 and a lower plate 134 arranged opposite each other, and two oppositely arranged inwardly recessed arc-shaped plates 135 connecting the upper plate 133 and the lower plate 134.

[0061] When the biomimetic negative Poisson's ratio energy-absorbing component 13 is subjected to axial compression, it can achieve constant resistance and efficient energy absorption through the deformation of the minimum repeating unit, thus meeting the requirements for absorbing strong impact energy.

[0062] The upper plate 133, lower plate 134, and arc plate 135 of the same minimum repeating unit have the same thickness; the thickness range is 0.5-12mm.

[0063] In some embodiments, the upper plate 133, lower plate 134, arc plate 135, and connecting horizontal plate 132 of all the smallest repeating units have the same thickness.

[0064] Please see Figure 8 As shown, in some embodiments, the vertical repeating units are arranged in a multi-layered structure with gradually varying sizes (gradually changing energy-absorbing components). Specifically, from top to bottom, the thickness of the upper plate 133, lower plate 134, arc-shaped plate 135 of the smallest repeating unit, and the connecting horizontal plate 132 connected to the arc-shaped plate of the smallest repeating unit increase in a gradient. The thickness difference between adjacent smallest repeating units in the same vertical repeating unit is 0.2-0.3 mm.

[0065] The gradient energy-absorbing component gives the energy absorption process a graded characteristic of "low resistance buffering first, and high resistance bearing later". It can not only cope with the flexible pressure relief of small deformation in the early stage, but also resist the rigid support of strong impact in the later stage, thus solving the limitation of the fixed energy absorption threshold of a single structure.

[0066] The push rod 8 includes a hollow disc structure 81 at the upper end and a hollow rod-shaped structure 82 at the lower end. The outer diameter of the hollow disc structure 81 is the same as the inner diameter of the energy-absorbing sleeve 7.

[0067] The lower end of the pressure relief push rod 8 of the second energy absorption component is connected to the end anchor rod assembly.

[0068] The end anchoring rod assembly includes a hollow end connecting rod 9 and a mixing structure connected to the end connecting rod 9. A slurry outlet 12 is provided on the peripheral wall of the end connecting rod 9.

[0069] In this embodiment, the stirring structure is a foldable end tail fin 10.

[0070] It should be noted that the mixing structure can also be a spiral blade type mixing structure, which can fully mix the resin anchoring agent to ensure the end anchoring effect.

[0071] Preferably, the blades of the spiral blade stirring structure are evenly distributed circumferentially along the end connecting rod.

[0072] In the implementation of this application, the central axes of the end connecting rod 6, the end energy-absorbing sleeve 4, the pressure-relief push rod 8, the energy-absorbing sleeve 7, and the end connecting rod 9 are collinear. The end connecting rod 6, the pressure-relief push rod 8, and the end connecting rod 9 are connected in sequence to form an internal grouting channel 11. Full-hole grouting can be achieved through this internal grouting channel 11 to fill the voids in the surrounding rock and form an anti-corrosion layer, thus taking into account both anchoring and anti-corrosion requirements.

[0073] The energy-absorbing anchor bolt is anchored with resin cartridges. When the displacement of the anchor bolt reaches the displacement limit of the push rod 8 or encounters a strong impact, grout is injected into the anchor bolt hole through the internal grouting channel 11, so that the annular gap between the hole wall and the bolt body is completely filled, realizing the transformation from end anchoring to full-length bonded anchoring, which greatly improves the ultimate bearing capacity of the anchor bolt and the surrounding rock deformation capacity.

[0074] This application also provides a construction method for the aforementioned biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor, including the following steps:

[0075] S1, using an anchor drilling rig to drill holes on the surface of the surrounding rock of the roadway that needs support, according to the predetermined position and hole depth, to drill surrounding rock holes that match the diameter of the biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor.

[0076] S2, put the resin anchoring agent into the depth of the borehole, and assemble the hollow end connecting rod 6, the graded energy-absorbing rod body assembly, and the end anchoring rod assembly according to the depth of the hole. Then, open the stirring structure at the end, insert the biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor into the borehole, and start the anchor drilling machine. The stirring structure at the end will fully stir the resin anchoring agent and push it to the bottom of the borehole and stop. Then, remove the anchor drilling machine.

[0077] S3, the limiting tray 5, the end energy-absorbing sleeve 4, the tray 3, and the annular pressure sensor 2 are sequentially mounted on the end connecting rod 6, and the nut 1 is screwed on the outer end of the end connecting rod 6. The torque is applied to the nut 1 to complete the anchor bolt pre-tightening support.

[0078] S4. After the resin anchoring agent has bonded, use a tensioning tool to tension the anchor rod body to achieve the predetermined locking force, so that the anchor rod is in a tensioned state. The tension force must be lower than the axial force threshold of the energy-absorbing sleeve 7 of the graded energy-absorbing rod assembly to cause pressure relief.

[0079] S5. Regularly observe the deformation of the surrounding rock in the roadway. When the displacement of the anchor bolt reaches the displacement limit of the pressure pusher 8 or encounters a strong impact, the anchor bolt is grouted through the internal grouting channel 11 formed by the end connecting rod 6, the pressure pusher 8, and the end connecting rod 9 to achieve full bonding and anchoring of the anchor bolt.

[0080] The working principle of this biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor is as follows:

[0081] When the surrounding rock of the tunnel deforms under the influence of complex factors such as geological stress and mining disturbance, the push rod 8 actively applies pressure to the biomimetic negative Poisson's ratio energy-absorbing component 13 at the moment it bears tensile load, forcing this special component to undergo compressive deformation. The biomimetic negative Poisson's ratio energy-absorbing component 13 draws on the mechanical properties of biological structures in nature, exhibiting efficient energy absorption capacity during compression, thus acting as a buffer. The end energy-absorbing sleeve 4 and the limiting tray 5 form a tight fit, together evenly transferring the concentrated load to the tunnel surface. The limiting tray 5 can precisely control the range of force application, preventing damage due to excessive stress concentration in local areas; while the end energy-absorbing sleeve 4 further plays a buffering role, continuously weakening the energy impact during load transfer, forming a double protective barrier.

[0082] Within the internal structure of the graded energy-absorbing rod assembly, the push rod 8 slides directionally along the axial direction of the sleeve, generating a specific push distance. This provides a buffer space for surrounding rock deformation while consistently providing constant resistance, ensuring stable output of support force. This characteristic effectively extends the working stroke of the anchor bolt and significantly improves its elongation, enabling it to better adapt to the deformation requirements of the surrounding rock.

[0083] The biomimetic negative Poisson's ratio energy-absorbing component 13 inside the energy-absorbing anchor bolt continuously absorbs energy through its own deformation throughout the process. When the surrounding rock undergoes slow and continuous large deformation or violent impact caused by rock bursts, the biomimetic negative Poisson's ratio energy-absorbing component 13 absorbs most of the energy due to its excellent deformation capacity, significantly reducing the load transmitted to the anchor bolt and preventing the anchor bolt from breaking due to the force of the breaking load. This effectively ensures the safety and stability of the roadway support system and provides reliable support for the normal production operations of the mine.

[0084] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A biomimetic negative Poisson's ratio multi-stage energy-absorbing anchor rod, characterized in that, Comprising The energy-absorbing anchor head assembly comprises a hollow end connecting rod, a limiting tray, an end energy-absorbing sleeve, a tray and a ring-shaped pressure sensor which are sequentially sleeved on the end connecting rod; the end energy-absorbing sleeve is provided with a bionic negative Poisson's ratio energy-absorbing component in the accommodation space formed by the outer peripheral wall of the end connecting rod; the upper end of the end connecting rod is provided with an outer thread matched with a nut; The hierarchical energy-absorbing rod body assembly comprises at least two energy-absorbing assemblies; each energy-absorbing assembly comprises a pressure-relief push rod, an energy-absorbing sleeve and a bionic negative Poisson's ratio energy-absorbing component; the uppermost energy-absorbing sleeve is connected with the lower end of the end connecting rod, and the bottom of the pressure-relief push rod is connected with the energy-absorbing sleeve or the terminal anchoring rod of the next energy-absorbing assembly; The terminal anchoring rod assembly comprises a hollow terminal connecting rod and a stirring structure connected with the terminal connecting rod; the terminal connecting rod is provided with a slurry outlet on the peripheral wall; The end connecting rod, the pressure-relief push rod and the terminal connecting rod are sequentially connected to form an internal grouting channel.

2. The biomimetic negative Poisson's ratio multistage energy-absorbing anchor rod according to claim 1, characterized in that, The bionic negative Poisson's ratio energy-absorbing component adopts a tortoise shell bionic structure, and comprises a plurality of vertical repeating units and a connecting horizontal plate connecting adjacent vertical repeating units; each vertical repeating unit comprises a plurality of minimum repeating units, and each minimum repeating unit comprises oppositely arranged upper and lower plates and two oppositely arranged inwardly recessed arc-shaped plates connecting the upper and lower plates.

3. The biomimetic negative Poisson's ratio multistage energy-absorbing anchor rod according to claim 2, characterized in that, The vertical repeating units are arranged in a multi-layer structure with gradually changing sizes; from top to bottom, the thicknesses of the upper plate, the lower plate, the arc-shaped plate and the connecting horizontal plate connected with the arc-shaped plate of the minimum repeating unit increase in gradient.

4. The biomimetic negative Poisson's ratio multistage energy-absorbing anchor rod according to claim 3, characterized in that, The thicknesses of the upper plate, the lower plate and the arc-shaped plate of the same minimum repeating unit are the same; the thickness difference between adjacent minimum repeating units in the same vertical repeating unit is 0.2-0.3 mm.

5. The biomimetic negative Poisson's ratio multistage energy-absorbing anchor rod according to claim 2, characterized by, The thicknesses of the upper plate, the lower plate, the arc-shaped plate and the connecting horizontal plate connected with the arc-shaped plate of the same minimum repeating unit are the same; the thicknesses range from 0.5 mm to 12 mm.

6. The biomimetic negative Poisson's ratio multistage energy-absorbing anchor rod according to claim 1, characterized in that, The outer diameter of the bionic negative Poisson's ratio energy-absorbing component is the same as the inner diameter of the energy-absorbing sleeve and the end energy-absorbing sleeve.

7. The bio-inspired negative Poisson's ratio multistage energy-absorbing anchor rod according to claim 1, characterized in that, The bionic negative Poisson's ratio energy-absorbing component is integrally formed.

8. The bio-inspired negative Poisson's ratio multistage energy-absorbing anchor rod according to claim 1, characterized in that, The pressure-relief push rod comprises a hollow disc structure at the upper end and a hollow rod structure at the lower part; the outer diameter of the hollow disc structure is the same as the inner diameter of the energy-absorbing sleeve; the central axes of the end connecting rod, the end energy-absorbing sleeve, the pressure-relief push rod, the energy-absorbing sleeve and the terminal connecting rod are collinear.

9. The bio-inspired negative Poisson’s ratio multistage energy-absorbing anchor rod according to claim 1, characterized in that, The stirring structure is a foldable terminal tail wing.

10. A construction method of a bionic negative Poisson's ratio multi-stage energy-absorbing anchor rod, used for constructing the bionic negative Poisson's ratio multi-stage energy-absorbing anchor rod according to any one of claims 1-9; characterized in that: The method comprises the following steps: S1, using an anchor rod drilling machine to drill a hole with a diameter matched with that of the bionic negative Poisson's ratio multi-stage energy-absorbing anchor rod on the surface of the surrounding rock of a roadway in need of support according to a predetermined position and hole depth; S2, the resin anchoring agent is put into the deep part of the drill hole, and the hollow end connecting rod, the hierarchical energy absorption rod body assembly, and the end anchoring rod assembly are assembled according to the hole depth, the end stirring structure is opened, the bionic negative Poisson's ratio multi-stage energy absorption anchor rod is inserted into the drill hole and the anchor drill is started, the end stirring structure fully stirs the resin anchoring agent and advances to the bottom of the drill hole and stops, and the anchor drill is removed; the hierarchical energy absorption rod body assembly comprises at least two energy absorption assemblies; each energy absorption assembly comprises a hollow pressure relief push rod, an energy absorption sleeve sleeved on the outer periphery of the pressure relief push rod, and a bionic negative Poisson's ratio energy absorption member arranged in the accommodation space formed by the energy absorption sleeve and the outer peripheral wall of the pressure relief push rod; the uppermost energy absorption sleeve is connected with the lower end of the end connecting rod, and the bottom of the pressure relief push rod is connected with the energy absorption sleeve of the next stage energy absorption assembly or the end anchoring rod; S3, the limiting tray, the end energy absorption sleeve, the tray, and the annular pressure sensor are sequentially sleeved on the end connecting rod, a nut is screwed on the outer end of the end connecting rod, and the nut is subjected to torque to complete anchor rod pre-tightening support; S4, after the resin anchoring agent is cured, the anchor rod body is tensioned by using a tensioning tool, a predetermined locking force is reached, the anchor rod is in a tensioned state, and the tensioning force needs to be lower than the axial force threshold at which the energy absorption sleeve of the hierarchical energy absorption rod body assembly yields; S5, the deformation condition of the surrounding rock of the roadway is observed regularly, when the displacement amount of the anchor rod reaches the displacement limit of the pressure relief push rod or impact is encountered, anchor rod grouting is performed through the internal grouting channel formed by the end connecting rod, the pressure relief push rod, and the end connecting rod, and full-bonding anchoring of the anchor rod is realized.

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