Tunnel self-adapting yielding and anti-seismic energy-dissipation anchor rod

Abstract

This invention discloses a tunnel adaptive pressure relief and seismic energy dissipation anchor, belonging to the field of tunnel engineering support and seismic technology. The anchor includes a viscous damper and a seismic energy dissipation anchor. The head of the viscous damper is fixed in the secondary lining structure of the tunnel, and the tail is connected to the rod body of the seismic energy dissipation anchor. The anchor head of the seismic energy dissipation anchor is anchored in the undisturbed stable surrounding rock, and its interior is injected with anchoring grout. The viscous damper includes a push rod piston, a high-strength spring, viscous damping fluid, and a steel sleeve shell, with a through hole on the push rod piston. Under static load, the viscous damper is embedded into the surrounding rock in stages, and the spring is compressed to achieve adaptive pressure relief. During an earthquake, the spring and damping fluid jointly dissipate energy, suppressing the deformation rate. After the earthquake, the spring drives the anchor to reset, reducing residual deformation. This invention integrates the functions of static load pressure relief and dynamic load energy dissipation reset, featuring modularity, strong adaptability, and excellent seismic performance, ensuring the safety of the tunnel throughout its entire life cycle.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering support and seismic resistance technology, and in particular to a tunnel adaptive pressure relief and seismic energy dissipation anchor. Background Technology

[0002] Tunnels in fault zones combine high-intensity earthquakes, weak surrounding rock, and high ground stress. Peak ground acceleration often exceeds 0.3g, and the surrounding rock is mostly Class IV-V soft rock or fractured rock. Creep-compression deformation continues for several months after excavation, with convergence often reaching 30-50cm. For such near-fault tunnels in mountainous areas experiencing high-intensity earthquakes, it is necessary not only to resist additional seismic loads but also to promptly control the large deformation of the weak and fractured surrounding rock.

[0003] Traditional fully bonded or end-anchored threaded steel anchors have an elongation of less than 6%, and the ultimate displacement corresponding to the design breaking force is far less than the actual requirements of large deformation of the surrounding rock. Under the coupled action of high ground stress and additional seismic loads, the anchors lack an effective energy dissipation mechanism, making them prone to instantaneous overload breakage, pallet collapse, and "string of candied haws" failure of the support system, which can lead to secondary lining cracking, invert arch heave, or even overall collapse. In addition, traditional anchors are difficult to self-reset after an earthquake, which seriously affects the long-term stability and seismic performance of the structure, and increases maintenance costs and difficulties.

[0004] Therefore, a type of anchor bolt is urgently needed for tunnels in mountainous areas with soft rock and large deformation under high-intensity earthquakes. This anchor bolt can not only gradually reduce pressure with the deformation of the surrounding rock during the static load stage and maintain stable support resistance, but also quickly dissipate energy and automatically reset under seismic action to ensure the safety of the tunnel throughout its entire life cycle. Summary of the Invention

[0005] The purpose of this invention is to provide a tunnel adaptive pressure-yielding and seismic energy-dissipating anchor, aiming to solve the support problem of large deformation tunnels in soft rock near fault zones under static load and seismic dynamic action. This anchor can adapt to large deformation of the surrounding rock and seismic load conditions. During construction and under static load, it can gradually yield pressure and smoothly control the support resistance, effectively supporting large deformation of the surrounding rock and preventing rockfall. During earthquakes, it rapidly dissipates energy and suppresses the deformation rate, and after the earthquake, it automatically resets itself through its own structure, significantly reducing residual deformation.

[0006] To achieve the above objectives, the present invention provides a tunnel adaptive pressure relief and seismic energy dissipation anchor, comprising a viscous damper and a seismic energy dissipation anchor. The head of the viscous damper is fixedly connected to the secondary lining structure of the tunnel, and the tail of the viscous damper is connected to the rod body of the seismic energy dissipation anchor. The anchor head of the seismic energy dissipation anchor is fixed in the undisturbed stable surrounding rock at a distance. Anchoring grout is injected inside the seismic energy dissipation anchor, and the anchoring grout extends to the anchor head. The deformation of the secondary lining structure of the tunnel and the seismic energy dissipation anchor are coordinated.

[0007] Preferably, the viscous damper includes a push rod piston, a high-strength spring, a viscous damping fluid, and a steel sleeve shell; one end of the steel sleeve shell is provided with an end cap plate, and the end cap plate is provided with bolt holes for fixing the viscous damper; the high-strength spring is sleeved on the rod of the push rod piston, and one end of the high-strength spring is fixedly connected to the push rod piston; the viscous damping fluid is filled in the inner cavity of the steel sleeve shell; the push rod piston is configured to move axially in the inner cavity of the viscous damper, and the free end of the push rod piston rod penetrates the steel sleeve shell and is connected to the rod of the seismic energy dissipation anchor.

[0008] Preferably, the push rod piston is provided with multiple through holes for the flow of viscous damping fluid.

[0009] Preferably, the anchor head of the seismic energy dissipation anchor is provided with at least one cone, which is embedded in the original stable surrounding rock at the far end.

[0010] Preferably, the interior of the seismic energy dissipation anchor is a hollow structure, and the anchoring grout fills the hollow structure and extends to the anchor head.

[0011] Preferably, the head of the viscous damper is fixed to the tunnel primary lining structure by expansion bolts, and then the head of the viscous damper is cast into the tunnel secondary lining structure.

[0012] Preferably, the viscous damping fluid is a non-Newtonian fluid.

[0013] Preferably, the viscous damper and the seismic energy dissipation anchor are detachably connected.

[0014] Preferably, the tail end of the viscous damper is provided with a threaded joint, and the end of the seismic energy dissipation anchor rod is screwed or welded to the threaded joint.

[0015] Therefore, the tunnel adaptive pressure relief and seismic energy dissipation anchor bolt of the present invention, with the above-mentioned structure, has the following beneficial effects: (1) The viscous damper and seismic energy dissipation anchor of the present invention adopt a modular and detachable structure. Different parameters (such as spring stiffness, anchor diameter and anchor length) can be selected according to actual engineering and geological conditions for combination and assembly, which can be adapted to different geological conditions and working conditions, facilitate transportation and installation, and form a cooperative force system with the tunnel primary lining structure and the tunnel secondary lining structure, with strong anchor reliability and durability.

[0016] (2) The present invention can adapt to large deformation of surrounding rock and seismic load conditions. In the static load stage, the viscous damper is embedded in the surrounding rock pores to achieve primary pressure relief, and the internal spring compression achieves secondary pressure relief, which can effectively support large deformation of surrounding rock and prevent surrounding rock collapse; during the earthquake, the energy is quickly dissipated and the deformation rate is suppressed by the combined action of high-strength spring and viscous damping fluid. After the earthquake, the elastic reset function of the high-strength spring is relied on to automatically reset, which greatly reduces residual deformation.

[0017] (3) The present invention is convenient to construct in engineering applications, compatible with existing processes, and the standardized manufacturing and modular combination improve the economy of the whole life cycle. In terms of safety, it can avoid disturbances caused by load changes, reduce the risk of collapse and secondary disasters, and comprehensively protect the safety of the tunnel throughout its entire life cycle.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] Figure 1 This is a structural schematic diagram of a specific embodiment of the tunnel adaptive pressure relief and seismic energy dissipation anchor bolt of the present invention; Figure 2 This is a schematic diagram of the end structure of the viscous damper in a specific embodiment of the present invention; Figure 3 This is a cross-sectional view of the static load stage pressure relief support according to a specific embodiment of the present invention; Figure 4 This is a working cross-sectional view of a specific embodiment of the present invention during an earthquake; Figure Labels 1-Viscous damper; 2-Seismic energy dissipation anchor; 3-Anchoring grout; 4-Anchor head; 5-Push rod piston; 6-High-strength spring; 7-Viscous damping fluid; 8-Steel sleeve shell; 9-Threaded joint; 10-End sealing plate; 11-Bolt hole; 12-Tunnel primary lining structure; 13-Void; 14-Rock loosening ring; 15-Original stable surrounding rock; 16-Expansion bolt; 17-Tunnel secondary lining structure. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0022] Example like Figure 1-4 As shown, this invention provides a tunnel adaptive pressure relief and seismic energy dissipation anchor, including a viscous damper 1 and a seismic energy dissipation anchor 2. Both the viscous damper 1 and the seismic energy dissipation anchor 2 are modularly manufactured. In practical engineering applications, appropriate parameters are selected for assembly based on geological conditions. For example, in soft rock tunnels with large deformation, a seismic energy dissipation anchor 2 with an anchorage length of 4.5–6.0 m is used to enhance the bond strength with the deep, stable surrounding rock. The anchor diameter is selected as 32 mm to improve the tensile bearing capacity. A viscous damper 1 with a length of 40 cm–60 cm is selected, and a high-strength spring 6 with a stiffness of 80–100 kN / m and a viscous damping fluid 7 with a damping coefficient of 150–200 kN·s / m are configured to ensure that the gradual pressure relief does not hinder the deformation of the surrounding rock, while dissipating the energy of large deformation. In hard rock tunnels in high seismic intensity zones, the anchorage length of the seismic energy dissipation anchor 2 is selected as 2-3m, and the diameter is selected as 28mm. The length of the viscous damper 1 is selected as 30cm-40cm. It is equipped with a high-strength spring 6 with a stiffness of 180-220kN / m and a viscous damping fluid 7 with a damping coefficient of 200-250kN·s / m to provide strong support resistance and quickly dissipate seismic energy.

[0023] The viscous damper 1 comprises a push rod piston 5, a high-strength spring 6, a viscous damping fluid 7, and a steel sleeve housing 8. The steel sleeve housing 8 has an end cap 10 at its end, with multiple bolt holes 11 pre-drilled on the end cap 10. Embedded parts or expansion bolts 16 are inserted into the bolt holes 11 to fix the viscous damper 1 to the tunnel structure. The high-strength spring 6 is sleeved on the rod of the push rod piston 5, with one end fixedly connected to the push rod piston 5 and the other end abutting against the inside of the steel sleeve housing 8 or the step of the push rod piston 5. It can withstand tension or pressure, providing support resistance for the tunnel structure. The viscous damping fluid 7, preferably a non-Newtonian fluid, fills the inner cavity of the steel sleeve housing 8 to absorb instantaneous energy and reduce the deformation rate of the tunnel structure. The push rod piston 5 is configured to move axially within the cavity of the viscous damper 1. The free end of the push rod piston 5 penetrates the end cap 10 of the steel sleeve housing 8 and extends out, connecting to the rod of the seismic energy dissipation anchor 2 via a threaded joint 9. The push rod piston 5 is provided with multiple small holes for the flow of viscous damping fluid 7. When the push rod piston 5 moves, the viscous damping fluid 7 flows through the small holes, generating damping force.

[0024] One end of the seismic energy dissipation anchor rod 2 is threaded to the rod body of the push rod piston 5 via a threaded joint 9, or connected by welding. The anchor head 4 of the seismic energy dissipation anchor rod 2 is embedded in the undisturbed stable surrounding rock 15 with good lithology at the distal end. The anchor head 4 is provided with at least one level of cone, preferably three levels of cone, with the spacing between each level of cone being 5-20 cm to enhance the anchoring force. The internal design of the seismic energy dissipation anchor rod 2 is a hollow structure. By injecting anchoring grout 3 into the anchor head 4, the rod body and the anchor head 4 are reinforced, further enhancing the anchoring force.

[0025] The construction and working process of this invention is as follows: Initial support stage (static load shedding process): First, the initial support for the tunnel is constructed. The anchor head 4 of the seismic energy dissipation anchor 2 is embedded in the undisturbed stable surrounding rock 15, and the anchor head 4 of the seismic energy dissipation anchor 2 is reinforced by injecting anchoring grout 3. Then, a hole 13, thinner and shorter than the viscous damper 1, is excavated in the loosened zone 14 of the surrounding rock at the tunnel entrance. The viscous damper 1 is placed in the hole 13, and the tail of the viscous damper 1 is connected to the rod body of the seismic energy dissipation anchor 2 through a threaded joint 9.

[0026] As the loosened zone 14 of the surrounding rock undergoes large deformation due to compression, the viscous damper 1 gradually embeds into the pre-reserved hole 13 in the surrounding rock under the pressure of the surrounding rock. This process achieves primary pressure relief support. When the viscous damper 1 reaches the bottom of the hole 13, the high-strength spring 6 inside it continues to compress under the action of the push rod piston 5, achieving secondary pressure relief support. This step-by-step pressure relief mechanism can smoothly control the support resistance, effectively support large deformations of the surrounding rock, and prevent surrounding rock collapse.

[0027] Subsequently, expansion bolts 16 are inserted into bolt holes 11 to fix the viscous damper 1 to the primary lining structure 12 of the tunnel. Finally, the secondary lining structure 17 of the tunnel is constructed, and the head of the viscous damper 1 is poured into concrete to completely fix the head of the viscous damper 1. The displacement of the secondary lining structure 17 and the head of the viscous damper 1 is coupled, and the deformation of the secondary lining structure 17 and the seismic energy dissipation anchor 2 is coordinated. At the same time, the problem of water leakage in the secondary lining structure 17 caused by the reserved hole 13 is avoided.

[0028] Earthquake occurrence stage (earthquake resistance and energy dissipation process): During normal tunnel operation, in the event of an earthquake, the seismic energy dissipation anchor 2 absorbs seismic energy through the viscous damper 1. Specifically, the vibration generated by the earthquake causes the push rod piston 5 to move axially at high frequency within the viscous damper 1, driving the high-strength spring 6 to reciprocate. The high-strength spring 6 deforms under stress, reducing the deformation amplitude of the tunnel secondary lining structure 17; the viscous damping fluid 7 flows through the small holes on the piston under the pressure of the push rod piston 5, generating viscous resistance, converting the seismic energy into heat energy for dissipation, thereby reducing the deformation rate of the tunnel secondary lining structure 17.

[0029] Post-earthquake recovery phase: After the earthquake, the high-strength spring 6, under the action of elastic restoring force, drives the push rod piston 5 to gradually return to its original position, thereby causing the tunnel secondary lining structure 17 to recover to its equilibrium position. This significantly reduces the residual deformation caused by the seismic load and ensures the long-term stability of the tunnel structure. The adaptive pressure relief and seismic energy dissipation anchor bolts of this invention automatically adjust under different conditions to protect the tunnel structure, improving not only the safety and reliability of the system but also extending its service life.

[0030] This invention, through the aforementioned structural design and working mechanism, achieves adaptive pressure relief under static load and efficient energy dissipation and resetting under seismic conditions, solving the problem of traditional anchor bolts' easy failure under complex geological conditions, and demonstrating significant technological progress. Furthermore, this invention employs a combination of a viscous damper and the anchor bolt body, achieving organic integration of functions through modular design.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A tunnel self-adapting yielding and anti-seismic energy-dissipation anchor rod, characterized in that, The system includes a viscous damper and a seismic energy dissipation anchor. The head of the viscous damper is fixedly connected to the secondary lining structure of the tunnel, and the tail of the viscous damper is connected to the rod body of the seismic energy dissipation anchor. The anchor head of the seismic energy dissipation anchor is fixed in the undisturbed stable surrounding rock at a distance. The seismic energy dissipation anchor is injected with anchoring grout, which extends to the anchor head. The deformation of the secondary lining structure of the tunnel and the seismic energy dissipation anchor are coordinated.

2. The tunnel adaptive pressure relief and seismic energy dissipation anchor bolt according to claim 1, characterized in that, The viscous damper comprises a push rod piston, a high-strength spring, a viscous damping fluid, and a steel sleeve shell. One end of the steel sleeve shell is provided with an end cap plate, and the end cap plate is provided with bolt holes for fixing the viscous damper. The high-strength spring is sleeved on the rod of the push rod piston, and one end of the high-strength spring is fixedly connected to the push rod piston. The viscous damping fluid is filled in the inner cavity of the steel sleeve shell. The push rod piston is configured to move axially in the inner cavity of the viscous damper, and the free end of the push rod piston rod penetrates the steel sleeve shell and is connected to the rod of the seismic energy dissipation anchor.

3. The tunnel adaptive pressure relief and seismic energy dissipation anchor bolt according to claim 2, characterized in that, The push rod piston is provided with multiple through holes for the flow of viscous damping fluid.

4. The tunnel adaptive pressure relief and seismic energy dissipation anchor bolt according to claim 2, characterized in that, The viscous damping fluid is a non-Newtonian fluid.

5. The tunnel adaptive pressure relief and seismic energy dissipation anchor bolt according to claim 1, characterized in that, The anchor head of the seismic energy dissipation anchor is provided with at least one cone, which is embedded in the original stable surrounding rock at the far end.

6. The tunnel adaptive pressure relief and seismic energy dissipation anchor bolt according to claim 5, characterized in that, The anchor head is provided with three levels of cones, with a spacing of 5 to 20 cm between each level of cone.

7. The tunnel adaptive pressure relief and seismic energy dissipation anchor bolt according to claim 1, characterized in that, The internal structure of the seismic energy dissipation anchor is hollow, and the anchoring grout fills the hollow structure and extends to the anchor head.

8. The tunnel adaptive pressure relief and seismic energy dissipation anchor bolt according to claim 1, characterized in that, The head of the viscous damper is fixed to the tunnel primary lining structure by expansion bolts, and then the head of the viscous damper is cast into the tunnel secondary lining structure.

9. A tunnel adaptive pressure relief and seismic energy dissipation anchor bolt according to claim 1, characterized in that, The viscous damper and the seismic energy dissipation anchor are detachably connected.

10. A tunnel adaptive pressure relief and seismic energy dissipation anchor bolt according to claim 9, characterized in that, The tail end of the viscous damper is provided with a threaded joint, and the end of the seismic energy dissipation anchor rod is screwed or welded to the threaded joint.

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