Self-resetting anchoring structure system resistant to strong earthquake impact and construction method thereof

Abstract

The application discloses an anti-strong-impact self-resetting anchoring structure system and a construction method thereof, and belongs to the technical field of rock-soil anchoring engineering, the system is composed of an anchor head assembly, a hollow anchor rod body, a central force transmission rod and a deep mechanical anchoring assembly, and a shallow bonding anchoring and deep mechanical anchoring dual-system time sequence switching bearing structure is constructed; the shallow bonding anchoring section independently bears under a static load working condition, the deep mechanical anchoring assembly automatically opens and self-locks to bear impact load under a strong dynamic load, the deep mechanical anchoring assembly is automatically unlocked and folded after the dynamic load is dissipated, and the system resets. The construction method comprises five processes of drilling, assembling and lowering, installing an anchor head, grouting and maintenance detection. The application significantly improves the anti-strong-impact performance of the anchoring system, realizes self-resetting and multiple cyclic loading, reduces the whole life cycle cost, and is suitable for rock-soil anchoring engineering, such as tunnels and slopes, in high-intensity seismic areas.

Description

Technical Field

[0001] This invention relates to the field of geotechnical anchoring engineering technology, and in particular to a self-resetting anchoring structure system resistant to strong earthquake impact and its construction method. Background Technology

[0002] Rock bolt support is a core technical means to control surrounding rock deformation and ensure structural stability in tunnel engineering, slope engineering, mining engineering, and underground space development. As engineering construction continues to extend into deeper rock masses, coupled with the large-scale construction of infrastructure in high-intensity earthquake zones, anchoring structures face severe challenges from extreme dynamic loads such as strong earthquakes and powerful blasting impacts. Strong earthquakes and powerful blasting impacts are characterized by instantaneous peak values, high energy, and cyclic fatigue loading. Under these extreme conditions, traditional anchoring structures are prone to brittle failure, rapid loss of anchoring force, and irreversible damage, making it difficult to restore the original load-bearing capacity after the earthquake, directly endangering the long-term operational safety of the engineering structure.

[0003] Currently, the anchoring technologies widely used in engineering mainly include three types: full-length bonded anchors, mechanical anchors, and yielding anchors. However, all of them have inherent defects that are difficult to overcome in strong earthquake impact scenarios. Traditional full-length bonded anchors achieve full-length bond anchoring between the rod and the surrounding rock through cement grout or chemical resin, relying on interfacial bond stress to transfer the load. The bond interface is a brittle medium, which is prone to instantaneous peeling failure under strong earthquake impact, resulting in a sharp loss of anchoring force. Moreover, the yielding of the rod or the interface failure are irreversible damages, and the anchoring capacity cannot be recovered after the earthquake. Mechanical anchors rely on the wedging force or friction between mechanical devices such as expansion shells and wedges and the borehole wall to achieve anchoring. After installation, the mechanical anchoring components are under tension and load for a long time. Continuous exposure to surrounding rock pressure can easily lead to fatigue failure, corrosion, and loosening. The instantaneous impact of a strong earthquake can easily cause plastic deformation of mechanical components, resulting in permanent loss of anchoring force that cannot be repaired. At the same time, this type of anchor cannot achieve time-sharing bearing of daily static loads and strong dynamic loads, resulting in poor adaptability. Yielding anchors are a new type of anchor developed to address the problem of large deformation in soft rock and deep, high-stress surrounding rock. They achieve yielding deformation under constant resistance through a built-in yielding device to absorb the deformation energy of the surrounding rock. However, the core design of this type of anchor is permanent deformation energy absorption, and the yielding deformation process is irreversible. After an earthquake, the anchor body is in an elongated state, resulting in a significant decrease in overall load-bearing capacity. Furthermore, its yielding device is mostly a disposable component, which cannot work cyclically in repeated impacts. This technology is mainly suitable for soft rock with large deformation conditions and is not well adapted to strong earthquake impacts on hard rock surrounding rock in high-intensity earthquake zones.

[0004] In summary, existing anchoring technologies mostly adopt a shallow-deep integrated, permanent anchoring load-bearing mode. Once installed, the anchoring device participates in the load-bearing process throughout its lifespan. Under extreme impacts such as strong earthquakes and blasting, it either suffers brittle failure or permanent plastic deformation, failing to achieve the self-resetting function of the anchoring system and lacking the ability to withstand multiple cyclic loads throughout its entire lifespan. This makes it difficult to meet the comprehensive requirements of safety, durability, and economy in deep engineering and geotechnical anchoring projects in high-intensity seismic zones. Therefore, it is necessary to develop a new type of anchoring structure system that can resist strong earthquake impacts, efficiently absorb deformation energy, and automatically reset after an earthquake. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a self-resetting anchoring structure system resistant to strong seismic impacts and its construction method.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a self-resetting anchoring structure system resistant to strong earthquake impact, including an anchor head assembly, a hollow anchor rod body, a central force transmission rod and a deep mechanical anchoring assembly; The hollow anchor body is embedded in the shallow surrounding rock, and the outer wall is grouted to form a shallow bonded anchoring section; the central force transmission member is inserted into the internal cavity of the hollow anchor body and can slide relative to the hollow anchor body axially. The deep mechanical anchoring assembly is installed in the deep stable rock layer at the bottom of the borehole and connected to the bottom end of the central force transmission rod; the anchor head assembly is fixed to the exposed end of the borehole of the hollow anchor body and connected to the central force transmission rod. The anchoring structure system forms a load-bearing structure with two parallel systems and time-sequential switching: a shallow bonded anchoring section and a deep mechanical anchoring component. Under static load conditions, the shallow bonded anchoring section bears the load independently, while the deep mechanical anchoring component is in a retracted standby state. Under strong dynamic load conditions, the deep mechanical anchoring component is triggered to open and lock, and the impact load is borne by the deep mechanical anchoring component, while the stress in the shallow bonded anchoring section is limited within the elastic limit; after the dynamic load dissipates, the deep mechanical anchoring component automatically unlocks and retracts, and the system resets to the initial static load bearing state.

[0007] Furthermore, the hollow anchor rod body is a metal rod with an axially penetrating cavity. The outer wall of the hollow anchor rod body is provided with centering supports at intervals along the axial direction to ensure the centering position of the anchor rod body in the borehole. The exposed end of the hollow anchor rod body is provided with a grouting hole, and the side wall of the hollow anchor rod body is provided with a number of grout outlet holes at intervals along its own axial direction.

[0008] Furthermore, the hollow anchor rod body is a metal rod with an axially penetrating cavity. The outer wall of the hollow anchor rod body is provided with centering supports at intervals along the axial direction to ensure the centering position of the anchor rod body in the borehole. The exposed end of the hollow anchor rod body is provided with a grouting hole, and the side wall of the hollow anchor rod body is provided with a number of grout outlet holes at intervals along its own axial direction.

[0009] Furthermore, the deep mechanical anchoring assembly includes a base, an anchoring cam assembly, a connecting rod, and a central sliding sleeve; The base is provided with a guide cone at one end away from the central force transmission rod, and an axial gap is reserved between the other end and the end of the central force transmission rod. The anchoring cam assembly includes several cam units evenly distributed along the circumference of the base. Each cam unit includes a cam body, a cam shaft, and friction teeth. The outer contour surface of the cam body is a logarithmic spiral surface, and the radial radius of the logarithmic spiral surface increases monotonically with the rotation angle. The cam body is rotatably connected to the base through the cam shaft. The friction teeth are integrally formed on the outer surface of the cam body and are sawtooth-shaped. The two ends of the connecting rod are respectively hinged to the cam body and the central sliding sleeve. The central sliding sleeve is sleeved on the guide column of the base, and the end of the central sliding sleeve away from the connecting rod is fixedly connected to the central force transmission rod.

[0010] Furthermore, the deep mechanical anchoring assembly has two working states: retracted standby and open anchoring. In the retracted standby state, the cam body rotates around the cam shaft to the minimum radial position, and the maximum radial dimension of the cam body is smaller than the borehole diameter, with a fit clearance of 2mm-8mm. In the open anchoring state, the central force transmission rod is under tension, causing the central sliding sleeve to move towards the borehole opening. The connecting rod pushes the cam body to rotate outward around the cam shaft. After the outer contour surface of the cam body contacts the borehole wall, a wedge-tightening effect is generated as the tension increases, and the radial pressure increases sharply until the angle between the connecting rod and the cam body reaches a preset angle, at which point it enters a self-locking state.

[0011] Furthermore, the anchor head assembly includes an anchor head base, an elastic energy storage unit, a limit adjustment unit, and a detachable end cap; The anchor head base is sleeved on the outer end of the hole of the hollow anchor rod body and is threadedly connected to the hollow anchor rod body. One end of the detachable end cap is threadedly connected to the outer circumferential surface of the anchor head base, and a closed cavity for installing the elastic energy storage unit and the limit adjustment unit is formed between the detachable end cap and the anchor head base. The elastic energy storage unit is located between the anchor head base and the limiting adjustment unit. The elastic energy storage unit adopts a disc spring assembly or a ring spring assembly. The limiting adjustment unit is an adjusting nut, which is threaded to the outer end of the hole of the central force transmission rod and is used to preset the initial compression of the elastic energy storage unit.

[0012] Furthermore, the anchor head assembly also includes a damping unit arranged in parallel with the elastic energy storage unit. The damping unit is also installed in the closed cavity formed between the detachable end cap and the anchor head base. The damping unit includes a damping cylinder, a damping piston, and a damping medium. The damping cylinder is fixedly connected to the outer end face of the anchor head base. The damping cylinder is an axially through sealed cavity structure. The damping medium completely fills the internal cavity of the damping cylinder, and the elastic energy storage unit is also located in the internal cavity of the damping cylinder. The damping piston is adapted to be embedded inside the damping cylinder, and the damping piston is fixedly connected to the outer end of the hole of the central force transmission rod. The damping piston has a throttling hole for the damping medium to flow through. When the central force transmission rod moves rapidly, the damping medium generates damping force through the throttling hole on the damping piston, consuming the impact kinetic energy.

[0013] Furthermore, the elastic energy storage unit, limit adjustment unit, damping unit, and central force transmission rod together constitute an independent replaceable module, which can be removed as a whole for inspection or replacement through the detachable end cap.

[0014] This invention also provides a construction method for a self-resetting anchoring structure system resistant to strong seismic impacts, applied to the aforementioned anchoring structure system, comprising the following steps: S1. Drilling: Drilling holes of the designed diameter and depth in the surrounding rock using a drilling rig; S2. Assembly and lowering: Assemble the deep mechanical anchoring components, central force transmission rods, and hollow anchor bodies into an integral structure outside the hole, and lower them into the borehole in the center so that the deep mechanical anchoring components reach the designed position of the deep stable rock layer. S3. Install the anchor head assembly: Fix the anchor head assembly to the exposed end of the hole of the hollow anchor rod body, rotate the adjusting nut of the limit adjustment unit, and preset the initial compression of the elastic energy storage unit. S4. Grouting: Grout is injected into the annular gap of the borehole and the surrounding rock fissures through the grouting holes of the hollow anchor rod body. After the grout solidifies, a shallow bonded anchoring section is formed. During the grouting process, the central force transmission rod is isolated to prevent consolidation. S5. Curing and Inspection: After the grout reaches the design strength, the pre-tightening force of the system is tested to confirm that the anchoring structure system is working normally.

[0015] The beneficial effects of this invention are: 1. This invention adopts a load-bearing mode with a dual-system time-switching of shallow bonded anchorage and deep mechanical anchorage. Under strong dynamic loads, the stress peak of the shallow bonded anchorage section can be limited within the material's elastic limit, effectively avoiding irreversible brittle failures such as bond interface peeling and plastic deformation of the rod, significantly improving the anchorage system's resistance to strong earthquakes and impacts. Furthermore, the deep mechanical anchorage component only works momentarily under impact conditions and is in a retracted standby state under normal conditions, which can effectively alleviate component fatigue, corrosion, and stress relaxation problems, significantly extending the overall service life of the anchorage system.

[0016] 2. This invention, through the coordinated operation of a reversible self-locking and unlocking deep mechanical anchoring component and an elastic energy storage unit, can achieve automatic retraction and reset after dynamic load dissipation, enabling the anchoring system to have multiple cyclic bearing capacity, thus solving the technical defects of traditional anchoring structures that permanently fail after earthquakes and cannot be reused.

[0017] 3. The elastic energy storage unit of the present invention adopts a threshold trigger design, which initiates deep anchoring action only when the dynamic load reaches a preset threshold. This can avoid ineffective mechanical action caused by minor disturbances. Combined with the damping unit, it can quickly dissipate impact kinetic energy and improve the system's working stability and impact resistance reliability.

[0018] 4. This invention adopts a modular and detachable anchor head assembly, and the internal functional units can be inspected and replaced as a whole without removing the embedded components. At the same time, the shallow anchoring length is greatly shortened, effectively reducing the amount of drilling work and reducing the construction cost and maintenance difficulty of the anchoring system throughout its entire life cycle. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention under static load.

[0020] Figure 2 This is a schematic diagram of the overall structure of the present invention under strong dynamic load.

[0021] Figure 3 This is a structural cross-sectional view used in this invention to illustrate the hollow anchor rod body.

[0022] Figure 4 This is a schematic diagram illustrating the structure of the centering support in this invention.

[0023] Figure 5 This is a schematic diagram of the structure of the deep mechanical anchoring assembly under static load in this invention.

[0024] Figure 6 This is a schematic diagram of the structure of the deep mechanical anchoring assembly used in this invention to illustrate the strong dynamic load.

[0025] Figure 7 This is a schematic diagram illustrating the structure of the cam body in this invention.

[0026] In the diagram: 1. Anchor head assembly; 11. Anchor head base; 12. Elastic energy storage unit; 13. Limit adjustment unit; 14. Damping unit; 141. Damping cylinder; 142. Damping piston; 143. Damping medium; 144. Throttling orifice; 15. Removable end cap; 2. Hollow anchor rod body; 21. Axially penetrating cavity; 22. Centering bracket; 23. Grouting hole; 24. Grout outlet hole; 25. Grout stop plug; 3. Central force transmission rod; 4. Deep mechanical anchoring assembly; 41. Base; 411. Guide column; 42. Guide cone; 43. Axial clearance; 44. Cam body; 45. Logarithmic spiral curved surface; 46. Camshaft; 47. Friction tooth; 48. Connecting rod; 49. Central sliding sleeve. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings.

[0028] This invention discloses a self-resetting anchoring structure system resistant to strong earthquake impact.

[0029] Reference Figure 1 and Figure 2 A self-resetting anchoring structure system resistant to strong earthquake impacts is disclosed, comprising an anchor head assembly 1, a hollow anchor rod body 2, a central force transmission member 3, and a deep mechanical anchoring assembly 4. These components work together to form a graded load-bearing and self-resetting anchoring system. The hollow anchor rod body 2 is embedded in the shallow fractured area of ​​the surrounding rock, and its outer wall is tightly bonded to the surrounding rock through grouting to form a shallow bonded anchoring section, serving as the core load-bearing structure under static load conditions. The central force transmission member 3 is coaxially inserted into the axially penetrating cavity 21 of the hollow anchor rod body 2. The two are not rigidly fixed together, allowing for relative displacement along the axial direction, providing the necessary degrees of freedom for dynamic load triggering, force transmission, and post-earthquake resetting.

[0030] The deep mechanical anchoring component 4 is positioned and installed in the deep stable rock layer at the bottom of the borehole. Its input end is fixedly connected to the bottom end of the hole of the central force transmission rod 3. It provides impact anchoring bearing capacity by relying on the high strength characteristics of the deep stable rock layer. The anchor head component 1 is fixedly assembled to the exposed end of the hole of the hollow anchor body 2. Its internal elastic component forms an elastic connection with the outer end of the hole of the central force transmission rod 3, realizing dynamic load energy storage, threshold triggering and reset driving force output. The whole constitutes a bearing structure in which the shallow bonded anchoring section and the deep mechanical anchoring component 4 are connected in parallel and time-sequentially.

[0031] This anchoring structure system possesses a precise working condition adaptation mechanism. Under static load conditions, only the shallow bonded anchoring section independently bears the static load of the surrounding rock and minor disturbance loads, while the deep mechanical anchoring component 4 remains in a retracted standby state, not contacting the borehole wall and not outputting anchoring force, thus avoiding fatigue, corrosion, and stress relaxation caused by long-term stress on mechanical components. Under strong dynamic load conditions, the deep mechanical anchoring component 4 is automatically triggered by the system and achieves geometric self-locking, instantly bearing high-energy impact loads, strictly limiting the stress peak of the shallow bonded anchoring section within the material's elastic limit range, thereby avoiding irreversible damage such as bond interface peeling and plastic deformation of the rod in the shallow anchoring section. After the dynamic load dissipates, the deep mechanical anchoring component 4 automatically unlocks and retracts under the action of elastic driving force, and the system quickly resets to the initial static load bearing state, possessing the ability to bear loads multiple times throughout its entire life cycle.

[0032] Reference Figure 3 and Figure 4 The hollow anchor body 2 is a long strip-shaped metal rod with an axially penetrating cavity 21, made of 20MnSi or HRB400 seamless steel pipe. The wall thickness of the rod is set according to the design anchoring force, usually 3mm to 8mm. The length of the rod matches the thickness of the shallow surrounding rock fracture zone, generally 2m to 6m, to ensure the coverage and bearing capacity of the shallow anchoring. Centering supports 22 are arranged axially at intervals on the outer wall of the hollow anchor body 2. The centering supports 22 are radially protruding annular. The structure or three-point support can ensure that the anchor body is centrally positioned in the borehole, ensuring uniform grout layer thickness and dense grouting. The exposed end of the hollow anchor body 2 has a grouting hole 23 for connecting the grouting equipment. Several grout outlet holes 24 are opened along the axial direction at intervals of 300mm to 500mm on the side wall to achieve uniform penetration of grout into the borehole annulus and surrounding rock fissures. A grout stop plug 25 is installed on the outer wall near the hole to effectively prevent grout from overflowing during the grouting process and ensure the quality of grouting formation.

[0033] Reference Figure 1 and Figure 2 The central force transmission member 3 is a solid metal member made of 40Cr or 35CrMo material after quenching and tempering, with a tensile strength ≥800MPa, and has excellent axial tensile performance and force transmission stability. The overall length of the central force transmission member 3 is greater than that of the hollow anchor body 2. Its bottom end extends out of the hollow anchor body 2 and connects with the deep mechanical anchoring component 4. Its outer end extends out of the hollow anchor body 2 and connects with the anchor head component 1, so as to realize the full transmission of trigger signal, anchoring tension and reset force.

[0034] The outer surface of the central force transmission rod 3 is provided with an epoxy coating or a zinc plating layer to form an anti-corrosion and friction-reducing layer, and is fitted with a polytetrafluoroethylene bushing to reduce axial sliding friction resistance and improve anti-corrosion and durability. The axial relative displacement stroke between the central force transmission rod 3 and the hollow anchor rod body 2 is limited by the anchor head assembly 1 limiting structure, generally 30mm to 100mm, to match the motion requirements of system triggering and resetting.

[0035] Reference Figures 5 to 7 The deep mechanical anchoring assembly 4 mainly consists of a base 41, an anchoring cam assembly, a connecting rod 48, and a central sliding sleeve 49, forming a reversible mechanical anchoring actuator that is self-locking and unlockable. The base 41 is a cylindrical metal component, with a guide cone 42 at one end away from the central force transmission rod 3 to facilitate the smooth entry of the component into the bottom of the borehole when it is lowered. An axial gap 43 is reserved between the other end and the bottom of the borehole of the central force transmission rod 3 to ensure that there is no axial force transmission under static load and to prevent the deep mechanical anchoring assembly 4 from being accidentally triggered.

[0036] The anchoring cam assembly comprises several cam units evenly distributed around the base 41. Each cam unit consists of a cam body 44, a cam shaft 46, and friction teeth 47. The cam body 44 is made of alloy steel with surface carburizing treatment, and has a surface hardness ≥ HRC58. It has high wear resistance and high impact resistance. Its outer contour is a logarithmic spiral curved surface 45. The radial radius of this curved surface increases monotonically with the rotation angle, which can gradually achieve progressive wedging with the hole wall during rotation. The cam body 44 is rotatably connected to the base 41 through the cam shaft 46. The outer surface is integrally formed with sawtooth-shaped friction teeth 47 with a tooth height of 0.5mm to 1mm, which improves the mechanical engagement with the rock wall and ensures the anchoring reliability under impact load.

[0037] The two ends of the connecting rod 48 are hinged to the cam body 44 and the central sliding sleeve 49 respectively, forming a stable connecting rod 48 drive mechanism. The central sliding sleeve 49 is coaxially sleeved on the guide post 411 of the base 41 and can slide freely along the axial direction of the base 41. The end away from the connecting rod 48 is threadedly fixed to the central force transmission rod 3 to realize the synchronous transmission of tension and reset force.

[0038] The deep mechanical anchoring component 4 has two stable working states: retracted standby and open anchoring. In the retracted standby state, the cam body 44 rotates around the cam shaft 46 to the minimum radial position, and the maximum radial dimension is smaller than the borehole diameter. The clearance between the two is 2mm to 8mm. There is no contact with the borehole wall and no anchoring force output. It is in a low-loss standby dormant state. In the open anchoring state, the central force transmission rod 3 is pulled and drives the central sliding sleeve 49 to move towards the borehole opening. The connecting rod 48 simultaneously pushes the cam body 44 to rotate outward around the cam shaft 46. After the logarithmic spiral curved surface 45 of the cam body 44 contacts the borehole wall, a wedging effect is gradually generated as the tension increases, and the radial pressure increases sharply. When the included angle between the connecting rod 48 and the cam body 44 reaches a preset angle of 7° to 12°, the mechanism enters a geometric self-locking state. Even if the tension of the central force transmission rod 3 is removed, the cam body 44 can still maintain the open anchoring state by relying on the interface friction and geometric self-locking characteristics, stably bearing the impact load and realizing the deep temporary anchoring function.

[0039] The anchor head assembly 1, serving as the system's control terminal and energy management unit, mainly consists of an anchor head base 11, an elastic energy storage unit 12, a limit adjustment unit 13, a detachable end cap 15, and a damping unit 14. The anchor head base 11 is coaxially sleeved on the outer end of the hole in the hollow anchor rod body 2, and the two are connected by a threaded detachable connection, facilitating on-site installation and subsequent maintenance. The detachable end cap 15 is threadedly connected to the outer circumferential surface of the anchor head base 11, and the two together form a closed cavity for installing the elastic energy storage unit 12 and the limit adjustment unit 13.

[0040] The elastic energy storage unit 12 is located between the anchor head base 11 and the limit adjustment unit 13. It adopts a disc spring group or a ring spring group. Its stiffness and stroke are specially designed. The trigger compression stroke corresponds to 80% to 90% of the elastic limit bearing capacity of the shallow bonded anchoring section. The deep anchoring action is triggered only when the dynamic load amplitude reaches the threshold, avoiding false triggering caused by minor disturbances such as light winds or small explosions. The limit adjustment unit 13 is an adjusting nut that is threaded to the outer end of the three holes of the central force transmission rod. By rotating the adjusting nut, the initial compression amount of the elastic energy storage unit 12 can be preset, ensuring the accuracy and stability of the system trigger threshold.

[0041] Reference Figure 2The anchor head assembly 1 is also provided with a damping unit 14 arranged in parallel with the elastic energy storage unit 12. The damping unit 14 is also assembled in the closed cavity formed between the detachable end cap 15 and the anchor head base 11. The damping unit 14 includes a damping cylinder 141, a damping piston 142, and a damping medium 143. The damping cylinder 141 is fixedly connected to the outer end face of the anchor head base 11 and is an axially through sealed cavity structure. The damping medium 143 fills the internal cavity of the damping cylinder 141. The elastic energy storage unit 12 is also located inside the damping cylinder 141. Inside the cavity, the two ends of the elastic energy storage unit 12 are connected to the damping piston 142 and the anchor base 11, respectively. The damping piston 142 is adapted to be embedded inside the damping cylinder 141 and is fixedly connected to the outer end of the hole of the central force transmission rod 3. A throttling hole 144 is opened on the damping piston 142 to allow the damping medium 143 to flow. When the central force transmission rod 3 moves rapidly with a strong dynamic load, the damping medium 143 flows through the throttling hole 144 to generate viscous damping force, which efficiently consumes the impact kinetic energy, avoids damage to mechanical components caused by high-speed impact, and improves the impact resistance stability of the system.

[0042] The elastic energy storage unit 12, the limit adjustment unit 13, the damping unit 14 and the central force transmission rod 3 together constitute an independent replaceable module. After removing the detachable end cap 15, the entire module can be taken out for inspection, debugging or replacement. There is no need to remove the hollow anchor rod body 2 and the grouting body buried in the rock layer, which reduces the maintenance cost of the whole life cycle and improves the efficiency of engineering operation and maintenance.

[0043] The working principle of the self-resetting anchoring structure system for resisting strong earthquake impact is as follows: The working mechanism of this anchoring structure system is realized by relying on the core mechanism of the time-sequential coordination of shallow bonded anchoring and deep mechanical anchoring, threshold triggering, self-locking anchoring, and elastic reset. It can adaptively match the stress requirements of static load, strong dynamic load, and all working conditions after the dynamic load dissipates.

[0044] Under static load conditions, the static load and minor disturbance load of the surrounding rock are borne independently by the shallow bonded anchoring section. The load is transferred to the anchor head assembly 1 through the hollow anchor body 2 to complete the locking. At this time, the central force transmission member 3 only bears the minor preload of the elastic energy storage unit 12. No axial tension is transferred to the deep mechanical anchoring assembly 4. The deep mechanical anchoring assembly 4 remains in a retracted standby state. The cam body 44 has no contact with the borehole wall and does not generate anchoring force, thus avoiding fatigue and corrosion caused by long-term stress on mechanical components.

[0045] Under strong dynamic load conditions, strong earthquakes or blasting impacts cause instantaneous large deformation of the surrounding rock. The hollow anchor rod 2 moves synchronously towards the borehole opening along with the shallow surrounding rock. The central force transmission rod 3 is displaced with lag due to the fixed constraint of the anchor head base 11 and the connection with the elastic energy storage unit 12. The two form an axial relative displacement and compress the elastic energy storage unit 12. When the dynamic load amplitude reaches 80% to 90% of the elastic limit bearing capacity of the shallow bonded anchoring section, the compression of the elastic energy storage unit 12 drives the central force transmission rod 3 to pull the central sliding sleeve 49 of the deep mechanical anchoring component 4 towards the borehole opening. The connecting rod 48 pushes the cam body 44 to rotate outward around the cam shaft 46. The logarithmic spiral curved surface 45 gradually weds into the borehole wall and enters a geometric self-locking state. The deep mechanical anchoring component 4 instantly bears all the impact load, strictly limiting the stress peak of the shallow bonded anchoring section within the material's elastic limit, and preventing interface peeling and plastic deformation of the rod. At the same time, the damping units 14 arranged in parallel work synchronously. The central force transmission rod 3 drives the damping piston 142 to move rapidly. The damping medium 143 generates viscous damping force through the throttling hole 144, which efficiently consumes the impact kinetic energy and avoids damage to mechanical components caused by high-speed impact.

[0046] After the dynamic load dissipates, the elastic energy storage unit 12 releases the stored elastic potential energy, driving the central force transmission rod 3 to reset towards the bottom of the hole. The central sliding sleeve 49 then moves backward, and the connecting rod 48 pulls the cam body 44 to rotate inward to release the geometric self-locking. The deep mechanical anchoring component 4 automatically retracts and returns to the standby state. The anchoring load is switched back to the shallow bonded anchoring section, and the system completely returns to the initial static load bearing state. It can cope with multiple reciprocating impact loads and realize the full life cycle cyclic bearing and self-resetting function.

[0047] The present invention also discloses a construction method for a self-resetting anchoring structure system resistant to strong earthquake impact.

[0048] A construction method for a self-resetting anchoring structure system resistant to strong seismic impacts, applied to the aforementioned anchoring structure system, includes the following steps: S1. Drilling: Using an engineering drilling rig, drill holes in the target surrounding rock area that meet the design diameter and depth requirements. The hole size is adapted to the component specifications, and the drilling depth reaches deep stable rock layers to provide a stable foundation for deep anchoring. S2. Assembly and lowering: Assemble the deep mechanical anchoring component 4, the central force transmission rod 3, and the hollow anchor body 2 into an integral structure, and lower it in the center along the borehole axis so that the deep mechanical anchoring component 4 reaches the designed position of the deep stable rock layer. S3. Install anchor head assembly 1: Fix anchor head assembly 1 to the exposed end of the hole of hollow anchor body 2, and preset the initial compression of elastic energy storage unit 12 by rotating the adjusting nut of limit adjustment unit 13, and calibrate the dynamic load trigger threshold of the system. S4. Grouting: Grout is injected into the annular gap of the borehole and the surrounding rock fissures through the grouting hole 23 of the hollow anchor body 2. After the grout solidifies, a shallow bonded anchoring section is formed. During the grouting process, isolation and protection measures are taken for the central force transmission member 3 to prevent the member from solidifying with the grout and to ensure that its axial sliding function is not affected. S5. Curing and Testing: After the grout reaches the design strength, the pre-tightening force of the entire anchoring system is tested to confirm that the deep mechanical anchoring component 4 is in a retracted standby state under static load and that the elastic energy storage unit 12 is not over-compressed. This verifies that all functions of the system are normal and the construction acceptance is completed.

[0049] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A self-resetting anchoring structural system resistant to strong seismic impact, characterized in that: It includes an anchor head assembly (1), a hollow anchor rod body (2), a central force transmission rod (3), and a deep mechanical anchoring assembly (4); The hollow anchor body (2) is buried in the shallow surrounding rock, and the outer wall is formed by grouting to form a shallow bonded anchoring section; the central force transmission rod (3) is inserted into the internal cavity of the hollow anchor body (2) and can slide relative to the hollow anchor body (2) axially; The deep mechanical anchoring assembly (4) is set in the deep stable rock layer at the bottom of the borehole and connected to the bottom end of the central force transmission rod (3); the anchor head assembly (1) is fixed to the exposed end of the hole of the hollow anchor body (2) and connected to the central force transmission rod (3). The anchoring structure system forms a load-bearing structure with a shallow bonded anchoring section and a deep mechanical anchoring component (4) connected in parallel and switched in sequence. Under static load conditions, the shallow bonded anchoring section bears the load independently, while the deep mechanical anchoring component (4) is in a retracted standby state. Under strong dynamic load conditions, the deep mechanical anchoring component (4) is triggered to open and lock, and the impact load is borne by the deep mechanical anchoring component (4). The stress of the shallow bonded anchoring section is limited within the elastic limit. After the dynamic load dissipates, the deep mechanical anchoring component (4) automatically unlocks and retracts, and the system is reset to the initial static load bearing state.

2. The self-resetting anchoring structure system for resisting strong seismic impacts according to claim 1, characterized in that: The hollow anchor rod body (2) is a metal rod with an axially penetrating cavity (21). The outer wall of the hollow anchor rod body (2) is provided with centering brackets (22) at intervals along the axial direction to ensure the centering position of the anchor rod body in the borehole. The exposed end of the hole of the hollow anchor rod body (2) is provided with a grouting hole (23), and the side wall of the hollow anchor rod body (2) is provided with a number of grout outlet holes (24) at intervals along its own axial direction.

3. The self-resetting anchoring structure system for resisting strong seismic impacts according to claim 2, characterized in that: The central force transmission rod (3) is a solid metal rod. The length of the central force transmission rod (3) is greater than that of the hollow anchor rod body (2). The bottom end of the hole of the central force transmission rod (3) extends out of the hollow anchor rod body (2) and is connected to the deep mechanical anchoring assembly (4). The outer end of the hole of the central force transmission rod (3) extends out of the hollow anchor rod body (2) and is connected to the anchor head assembly (1).

4. The self-resetting anchoring structure system for resisting strong seismic impacts according to claim 3, characterized in that: The deep mechanical anchoring assembly (4) includes a base (41), an anchoring cam assembly, a connecting rod (48), and a central sliding sleeve (49); The base (41) has a guide cone (42) at one end away from the central force transmission rod (3), and an axial gap (43) is reserved between the other end and the end of the central force transmission rod (3). The anchoring cam assembly includes several cam units evenly distributed around the base (41). Each cam unit includes a cam body (44), a cam shaft (46), and friction teeth (47). The outer contour surface of the cam body (44) is a logarithmic spiral surface (45). The radial radius of the logarithmic spiral surface (45) increases monotonically with the rotation angle. The cam body (44) is rotatably connected to the base (41) through the cam shaft (46). The friction teeth (47) are integrally formed on the outer surface of the cam body (44) and are sawtooth-shaped. The two ends of the connecting rod (48) are respectively hinged to the cam body (44) and the central sliding sleeve (49). The central sliding sleeve (49) is sleeved on the guide post (411) of the base (41). The end of the central sliding sleeve (49) away from the connecting rod (48) is fixedly connected to the central force transmission rod (3).

5. The self-resetting anchoring structure system for resisting strong seismic impacts according to claim 4, characterized in that: The deep mechanical anchoring assembly (4) has two working states: retracted standby and open anchoring. In the retracted standby state, the cam body (44) rotates around the cam shaft (46) to the minimum radial position. The maximum radial dimension of the cam body (44) is smaller than the borehole diameter, and the fit clearance is 2mm to 8mm. In the open anchoring state, the central force transmission rod (3) is stretched, causing the central sliding sleeve (49) to move towards the borehole opening. The connecting rod (48) pushes the cam body (44) to rotate outward around the cam shaft (46). After the outer contour surface of the cam body (44) contacts the borehole wall, a wedge-tightening effect is generated as the tension increases, and the radial pressure increases sharply until the angle between the connecting rod (48) and the cam body (44) reaches the preset angle, and then it enters the self-locking state.

6. The self-resetting anchoring structure system for resisting strong seismic impact according to claim 5, characterized in that: The anchor head assembly (1) includes an anchor head base (11), an elastic energy storage unit (12), a limit adjustment unit (13), and a detachable end cap (15); The anchor base (11) is sleeved on the outer end of the hole of the hollow anchor body (2) and threadedly connected to the hollow anchor body (2). One end of the detachable end cap (15) is threadedly connected to the outer circumferential surface of the anchor base (11), and a closed cavity for installing the elastic energy storage unit (12) and the limit adjustment unit (13) is formed between the detachable end cap (15) and the anchor base (11). The elastic energy storage unit (12) is located between the anchor head base (11) and the limiting adjustment unit (13). The elastic energy storage unit (12) adopts a disc spring group or a ring spring group. The limiting adjustment unit (13) is an adjusting nut. The adjusting nut is threaded to the outer end of the hole of the central force transmission rod (3) and is used to preset the initial compression amount of the elastic energy storage unit (12).

7. A self-resetting anchoring structure system resistant to strong seismic impact as described in claim 6, characterized in that: The anchor head assembly (1) also includes a damping unit (14) arranged in parallel with the elastic energy storage unit (12). The damping unit (14) is also installed in the closed cavity formed between the detachable end cap (15) and the anchor head base (11). The damping unit (14) includes a damping cylinder (141), a damping piston (142), and a damping medium (143). The damping cylinder (141) is fixedly connected to the outer end face of the anchor base (11). The damping cylinder (141) is an axially through sealed cavity structure. The damping medium (143) completely fills the internal cavity of the damping cylinder (141), and the elastic energy storage unit (12) is also set in the internal cavity of the damping cylinder (141). The damping piston (142) is adapted to be embedded inside the damping cylinder (141), and the damping piston (142) is fixedly connected to the outer end of the hole of the central force transmission rod (3). The damping piston (142) is provided with a throttling hole (144) for the damping medium (143) to flow. When the central force transmission rod (3) moves rapidly, the damping medium (143) generates damping force through the throttling hole (144) on the damping piston (142) and consumes the impact kinetic energy.

8. The self-resetting anchoring structure system for resisting strong seismic impact according to claim 7, characterized in that: The elastic energy storage unit (12), limit adjustment unit (13), damping unit (14) and central force transmission rod (3) together constitute an independent replaceable module, which can be taken out as a whole for inspection or replacement through the detachable end cap (15).

9. A construction method for a self-resetting anchoring structural system resistant to strong earthquake impact, characterized in that: The method applied to the anchoring structure system of claim 8 includes the following steps: S1. Drilling: Drilling holes of the designed diameter and depth in the surrounding rock using a drilling rig; S2. Assembly and lowering: Assemble the deep mechanical anchoring assembly (4), the central force transmission rod (3), and the hollow anchor body (2) into an integral structure outside the hole, and lower it into the borehole in the center so that the deep mechanical anchoring assembly (4) reaches the designed position of the deep stable rock layer. S3. Install the anchor head assembly (1): Fix the anchor head assembly (1) to the exposed end of the hole of the hollow anchor body (2), rotate the adjusting nut of the limit adjustment unit (13), and preset the initial compression of the elastic energy storage unit (12). S4. Grouting: Grout is injected into the annular gap of the borehole and the surrounding rock fissures through the grouting hole (23) of the hollow anchor body (2). After the grout solidifies, a shallow bonded anchoring section is formed. During the grouting process, the central force transmission member (3) is isolated to prevent consolidation. S5. Curing and Inspection: After the grout reaches the design strength, the pre-tightening force of the system is tested to confirm that the anchoring structure system is working normally.

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