A tunnel support structure and a support method

Abstract

This invention relates to the field of tunnel support technology, and more particularly to a tunnel support structure and method, comprising an upper steel arch frame and a lower steel arch frame for fitting against the inner wall of the tunnel and supporting the surrounding rock. A bottom plate and a top plate are respectively provided on the opposing end faces of the upper and lower steel arch frames. A pressure-relief component is provided between the bottom plate and the top plate to adapt to the slow steady-state creep condition of the surrounding rock. The invention also includes a self-starting damping protection mechanism, comprising a detection trigger component and a damping unit. This invention adds a self-starting damping protection mechanism to the basic support structure, achieving dual protection of conventional pressure relief and sudden impact damping, adapting to extreme scenarios such as rock bursts and sudden collapse of surrounding rock. It requires no external sensors, controllers, or energy sources, and has high reliability. Furthermore, the reliability and stability of the damping function activation are ensured through a precise contact unit and an anti-rebound locking unit.

Description

Technical Field

[0001] This invention relates to the field of tunnel support technology, and in particular to a tunnel support structure and support method. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] As my country's infrastructure construction, including transportation and energy, extends into deeper and more complex geological areas, tunnel engineering faces increasingly harsh geological conditions. Complex working conditions such as high ground stress, large deformation of soft rock, rock bursts, and fault fracture zones occur frequently, placing extremely high demands on the safety and adaptability of tunnel support structures.

[0004] As the core load-bearing component of the initial support for tunnels, the steel arch frame's main function is to resist the surrounding rock load, constrain its deformation, and prevent instability of the initial support structure. In existing technologies, support structures designed to address surrounding rock deformation often employ a combination of "yield springs + support columns." The yield springs absorb the deformation energy of the surrounding rock through elastic deformation, achieving smooth yielding. Finally, the support columns limit the maximum deformation, preventing excessive shrinkage of the steel arch frame.

[0005] However, such existing support structures have significant technical defects in practical applications: existing structures can only adapt to slow steady-state creep conditions of surrounding rock. When encountering sudden impacts such as sudden collapse or rock burst of surrounding rock, the surrounding rock load will act on the upper steel arch frame at extremely high speed, causing the compression spring to be compressed to its elastic limit in an instant. This makes it unable to continuously absorb impact energy, resulting in a hard collision between the upper steel arch frame and the lower steel arch frame and the support column. This causes irreversible damage such as tearing of the steel arch frame flange, buckling of the web plate, and breakage of the connection node. In severe cases, it may even lead to the collapse of the initial support structure, threatening construction and operation safety. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned shortcomings by providing a tunnel support structure and support method.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a tunnel support structure, comprising an upper steel arch frame and a lower steel arch frame for fitting against the inner wall of the tunnel and supporting the surrounding rock, wherein a bottom plate and a top plate are respectively provided on the opposing end faces of the upper steel arch frame and the lower steel arch frame, and a pressure-relief component for adapting to the slow steady-state creep condition of the surrounding rock is provided between the bottom plate and the top plate, and further comprising: The self-starting damping protection mechanism includes a detection trigger component for converting the speed of the upper steel arch frame movement into the magnitude of centrifugal force and automatically triggering the damping function when the centrifugal force exceeds a set value, and a damping unit disposed on the base plate for damping the upper steel arch frame moving rapidly downward.

[0008] Furthermore, the detection triggering component includes a drive unit disposed between the bottom plate and the top plate and transmitting force under the rapid movement of the upper steel arch frame, and a centrifugal detection unit for triggering the damping unit and driven by the drive unit.

[0009] Furthermore, two guard plates are fixed at both ends of the lower steel arch frame, and the guard plates are provided with openings for the upper steel arch frame to move down and slide to connect with the corresponding part of the upper steel arch frame. The centrifugal detection unit includes a horizontal plate fixed between the two guard plates, a mounting plate located under the horizontal plate and rotating horizontally, two sliders sliding separately along their radial lines on the mounting plate, a movable rod rotatably mounted on each slider, a common rotating block rotatably mounted on the adjacent ends of the two movable rods, a small square column rotatably mounted on the rotating block, the small square column penetrating the end face of the horizontal plate and moving vertically, a large square column formed by a transition slope at the upper end of the small square column, and a first spring connected to the horizontal plate on the outer wall of the large square column.

[0010] Furthermore, the damping unit includes mounting plates disposed opposite to both sides of the small square column, two F-shaped abutment plates with bendable and deformable lower ends fixed to the front and rear ends of the upper steel arch frame and fixedly connected to the base plate, a pressing column is horizontally slidably disposed on the mounting plate, and the pressing column is fixedly connected to the mounting plate by a second spring, and a roller adapted to abut against the transition slope is disposed on the end of the pressing column corresponding to the small square column, and a rod is rotatably disposed on the other end of the pressing column, and multiple sets of cams are disposed on the rod, and long arc-shaped protrusions are disposed on the periphery of the cams, and the multiple sets of cams are connected by connecting rods, and a blocking rod is eccentrically disposed on the outermost cam, and the blocking rod contacts the stop block disposed at the end of the pressing column; As the small square column moves downward, the roller smoothly passes through the transition slope and contacts the outer wall of the large square column, causing the extrusion column to move horizontally outward under the support of the second spring. At the same time, the cam contacts and rotates against the inner wall of the downward-moving F-shaped abutment plate, transmitting the gradually increasing frictional extrusion force between the cam and the F-shaped abutment plate, as well as the limiting and holding effect of the blocking rod and the stop block, causing the lower end of the F-shaped abutment plate to bend and deform outward, forming a gradual resistance against the upper steel arch frame.

[0011] Furthermore, the drive unit includes a rack fixedly mounted on the base plate, a large gear rotatably mounted on the top plate and adapted to be connected to the rack, and a small gear located on one side of the large gear and adapted to be connected to the large gear. A rotating shaft passes through the end face of the small gear, and a first bevel gear is fixed to one end of the rotating shaft away from the small gear. A second bevel gear is adapted to be mounted on the first bevel gear. The second bevel gear is coaxially mounted with the mounting plate and fixed to the top plate. The rapid downward movement of the upper steel arch frame drives the rack to rotate the large gear. The torque transmitted through the small gear and the rotating shaft drives the first bevel gear to rotate at an increased speed. Under the transmission action of the first bevel gear and the second bevel gear, the mounting plate rotates at high speed, transmitting centrifugal force to make the two sliders slide outward. Then, under the action of the movable rod and the rotating block, the small square column moves downward.

[0012] Furthermore, a stop post is provided at the end of the extrusion column and on the lower side of the rod; The rod is equipped with a precise contact unit for controlling and realizing the initial contact between the cam and the surface of the F-shaped contact plate; The precise abutment unit includes a drive gear coaxially mounted on the rod body, an abutment toothed rod adapted to the drive gear and fixed on the top plate, a spherical weight is provided at the end of the blocking rod away from the cam, and an annular weakening groove is provided at the other end of the blocking rod, with the movement path of the annular weakening groove passing through the stop post; When the extrusion column passes the transition slope and moves outward under the pressure of the outer wall of the large square column, the drive gear meshes with the abutting rack, driving the cam to rotate; after the drive gear disengages from the abutting rack, the cam continues to rotate under the gravity of the spherical weight until it abuts against the F-shaped abutting plate; and when the blocking rod is pressed against the stop column, the blocking rod breaks off from the annular weakening groove, causing the spherical weight to separate from the cam.

[0013] Furthermore, the horizontal plate is provided with an anti-rebound locking unit for limiting and locking the large square column; The anti-rebound locking unit includes a U-shaped plate fixed to the horizontal plate and spaced apart on the side of the large square column, and a spiral plate extending on the side of the large square column. A locking post is slidably disposed on the U-shaped plate and moves linearly toward the spiral plate and presses against it. A locking spring is horizontally fixed on the locking post at the inner end of the U-shaped plate.

[0014] Furthermore, the outer wall of the F-shaped contact plate is provided with multiple sets of reinforcing plates arranged side by side, and the reinforcing plates are right-angled triangular structures with a bottom wider than the top.

[0015] Furthermore, the pressure relief assembly includes multiple sets of pressure relief springs for support, which are disposed between the bottom plate and the top plate and are evenly distributed. Each pressure relief spring has a support column fixed to the top plate coaxially disposed inside it, and the upper end of the support column does not contact the bottom plate and leaves a clearance space. The upper horizontal plane of the support column is located above the end face of the large square column.

[0016] A tunnel support method specifically includes the following steps: S1, Conventional creep relief: In the scenario of slow steady-state creep of the surrounding rock, the upper steel arch is smoothly relieved by relief springs. The self-starting damping protection mechanism is not activated, and the rigid limit of the relief stroke is completed by the support column. S2, Sudden Impact Mitigation: In the event of sudden collapse of surrounding rock or rock burst causing the upper steel arch to move rapidly downward, a self-activating mitigation protection mechanism is activated to form a two-level collaborative protection to smoothly dissipate the impact energy. S3, Reset and Reuse: After the impact condition ends, the support structure is fully inspected and vulnerable parts are replaced. The motion mechanism is reset and the parameters are recalibrated to enable the reuse of the support structure.

[0017] The beneficial effects of this invention are reflected in: This invention adds a self-activating damping protection mechanism to the basic support structure, achieving dual protection against conventional pressure relief and sudden impact damping. It is suitable for extreme scenarios such as rock bursts and sudden collapse of surrounding rock, requiring no external sensors, controllers or energy sources, and has high reliability. Furthermore, through a precise contact unit and an anti-rebound locking unit, the reliability and stability of the damping function activation are ensured. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 for Figure 1 A magnified schematic diagram of the central part of the structure; Figure 3 for Figure 2 Diagram of the split structure; Figure 4 for Figure 3 Schematic diagram of the rear view of the lower and middle steel arch frame; Figure 5 for Figure 4 Schematic diagram of the detection trigger component structure; Figure 6 for Figure 5 A magnified schematic diagram of a portion of the detection trigger component; Figure 7 for Figure 5 Schematic diagram of the medium-resistance buffer unit structure; Figure 8 for Figure 7 Enlarged structural diagram at point A Figure 9 A schematic diagram of the anti-rebound locking unit structure; Figure 10 This is a schematic diagram of the cam's side view structure.

[0019] In the picture: 1. Upper steel arch frame; 2. Lower steel arch frame; 3. Base plate; 4. Top plate; 5. Guard plate; 6. Pressure relief spring; 7. Support column; 8. F-shaped contact plate; 9. Reinforcing plate; 10. Gear rack; 11. Large gear; 12. Small gear; 13. Rotating shaft; 14. First bevel gear; 15. Fixing frame; 16. Second bevel gear; 17. Mounting plate; 18. Slider; 19. Movable rod; 20. Rotating block; 21. Small square column; 22. 23. Large square column; 24. Transition slope; 25. First spring; 26. Horizontal plate; 27. Extrusion column; 28. Mounting plate; 29. ​​Cam; 20. Roller; 31. Second spring; 32. Stop bar; 33. Stop block; 34. Rod body; 35. Drive gear; 36. Abutting toothed rod; 37. Annular weakening groove; 38. Stop column; 39. Connecting rod; 40. Spherical weight; 41. Locking column; 42. Recurve plate; 43. Locking spring. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figure 1-10 This invention discloses a tunnel support structure that can adapt to both slow steady-state creep and sudden rapid impact of the surrounding rock.

[0022] like Figure 2As shown, the support structure includes an upper steel arch 1 fixed to the inner wall of the tunnel and a lower steel arch 2 located below it. A base plate 3 is welded or bolted to the lower end face of the upper steel arch 1, and a horizontal top plate 4 is similarly welded / bolted to the upper end face of the lower steel arch 2. A conventional pressure-relief assembly, specifically multiple evenly distributed pressure-relief springs 6, is provided between the base plate 3 and the top plate 4. Each pressure-relief spring 6 has a coaxial support column 7 inside, the lower end of which is welded to the top plate 4, and a gap (i.e., a clearance space) is left between its upper end and the lower surface of the base plate 3. During slow creep of the surrounding rock, the upper steel arch 1 slowly moves downward, compressing the pressure-relief springs 6 to achieve pressure relief; when the deformation reaches the design limit, the base plate 3 contacts the top of the support column 7, forming a rigid support to prevent further compression.

[0023] To guide the upper steel arch frame 1, the two ends of the lower steel arch frame 2 are fixed with guard plates 5 by bolts, and the guard plates 5 are grooved with vertical openings. The outer side of the end of the upper steel arch frame 1 is embedded in the openings and can slide up and down along them.

[0024] To mitigate the rapid downward movement of the upper steel arch 1, and to completely prevent hard collisions between the upper steel arch 1 and the lower steel arch 2 and support column 7, thus eliminating irreversible damage such as tearing of the steel arch wing plates, buckling of the web plates, and breakage of joints, a self-activating damping protection mechanism is also included. This mechanism comprises a detection trigger component and a damping unit.

[0025] The detection triggering components include a drive unit and a centrifugation detection unit.

[0026] like Figure 4-6 As shown, the drive unit includes a rack 10, a large gear 11, a small gear 12, a rotating shaft 13, a first bevel gear 14, and a second bevel gear 16. The upper end of the rack 10 is welded to the base plate 3 and extends vertically downward. The large gear 11 is rotatably mounted on the top plate 4 via a bearing / central shaft and meshes with the rack 10. The small gear 12 is meshed with one side of the large gear 11. The rotating shaft 13 is fixedly mounted through the end face of the small gear 12, and the first bevel gear 14 is keyed to or integrally machined at the other end of the rotating shaft 13. The first bevel gear 14 meshes with a vertically arranged second bevel gear 16, the shaft of which rotates vertically upward.

[0027] It should be noted that the size ratio of the large gear 11 to the small gear 12 can be adjusted according to actual needs. The large gear 11 can drive the small gear 12 to rotate quickly, thereby increasing the rotational speed of the small gear 12 and preparing for the subsequent large centrifugal force of the slider 18.

[0028] The centrifugal testing unit includes a horizontally arranged mounting plate 17, which is keyed or flanged to the upper end of the shaft of the second bevel gear 16. A slide rail is mounted on the upper surface of the mounting plate 17 along its diameter, and two sliders 18 symmetrically fit and slide on the slide rail. Each slider 18 has a movable rod 19 hinged to it via a pin. The upper ends of the two movable rods 19 are hinged together to a rotating block 20 and connected via a pin. A small vertical square post 21 is rotatably connected to the center of the rotating block 20, and the small square post 21 passes upward through a square hole (clearance fit) in a horizontal plate 25. The horizontal plate 25 is horizontally welded between two guard plates 5. The upper end of the small square post 21 is integrally formed into a larger square post 22 with a larger cross-section through a transition slope 23 (e.g., a tapered surface that gradually increases in size). First springs 24 are symmetrically welded to the outer sides of the large square post 22, and the lower ends of the first springs 24 are welded to the horizontal plate 25 to provide an upward restoring force.

[0029] In practice, when sudden impacts such as rockfall or rock bursts occur, the upper steel arch 1 moves rapidly downwards. The rack 10 drives the large gear 11 to rotate, which in turn drives the small gear 12 mounted on its side to rotate at high speed. The rapid rotation of the small gear 12 drives the rotating shaft 13 to rotate rapidly. The rotating shaft 13, through the meshing of the first bevel gear 14 and the second bevel gear 16, drives the mounting plate 17 to rotate rapidly. The centrifugal force generated by the rapid rotation of the mounting plate 17 causes the two sliders 18 to be thrown outwards, forcing the small square column 21 and the large square column 22 to overcome the elastic force of the first spring 24 and move downwards. When the speed of the upper steel arch 1 exceeds the design threshold (e.g., 0.1 m / s, which can be adjusted according to the mass of the centrifugal slider and the spring stiffness), the large square column 22 will move downwards by a significant stroke. Conversely, during slow creep, the centrifugal force is insufficient to overcome the elastic force of the first spring 24, and the large square column 22 will not undergo triggered displacement.

[0030] like Figure 3 , Figure 7 As shown, the damping unit uses an F-shaped contact plate 8. The upper end of the F-shaped contact plate 8 is snapped onto the base plate 3 and fixedly connected to the base plate 3 by bolts. Its lower end is a free end and can undergo elastic bending deformation under external force. Multiple sets of reinforcing plates 9 are welded side by side on the outer wall of the F-shaped contact plate 8. The reinforcing plates 9 have a right-angled triangular structure and are wider at the bottom and narrower at the top. The setting of the reinforcing plates 9 with a right-angled triangular structure and a wider bottom and narrower top helps to ensure the consistency of the structural strength of the F-shaped contact plate 8. It allows the F-shaped contact plate 8 to expand and deform evenly under the compression of the subsequent cam 28, so that the frictional resistance between the cam 28 and the F-shaped contact plate 8 does not rise or fall suddenly, preventing contact separation and slippage caused by excessive deformation, and allowing the movement speed of the upper steel arch frame 1 to decrease smoothly and linearly.

[0031] In addition, the damping unit also includes mounting plates 27 (mounting plates 27 are fixed to the upper surface of the top plate 4 by bolts) positioned opposite each other on both sides of the small square column 21. A pressing column 26 is slidably mounted on the mounting plate 27 (the mounting plate 27 has guide holes, and the pressing column 26 slides into the guide holes), and the pressing column 26 is connected to the mounting plate 27 by a second spring 30 (one end of the second spring 30 abuts against the side wall of the mounting plate 27, and the other end abuts against the shoulder on the pressing column 26). A roller 29 is mounted on the end of the pressing column 26 near the small square column 21 via a rolling bearing, and a rotating rod 33 is mounted on the other end of the pressing column 26. Multiple sets of cams 28 are fixedly mounted on the rod 33 via a key connection or set screw. All sets of cams 28 are connected by a connecting rod 38, and a blocking rod 31 is eccentrically mounted on the outermost cam 28 (one end of the blocking rod is threaded onto the eccentric position of the cam), and the blocking rod 31 contacts a stop block 32 welded to the end of the pressing column 26. In the initial state, the side wall of the blocking rod 31 abuts against the stop block 32 fixed to the end face of the extrusion column 26 to restrict the free rotation of the rod.

[0032] It should be noted that the stop block 32 can be made of magnetic material and magnetically attracted and fixed to the stop rod 31.

[0033] Further optimization involves forming a long arc-shaped protrusion on the outer periphery of cam 28. The radial lift rate λ of cam 28 is controlled to be 0.06~0.12 mm / mm. When the lift rate exceeds 0.12 mm / mm, the increase in protrusion height per unit arc length of cam 28 is too large. Even a small rotation angle of cam 28 will generate an extremely large radial compressive force, which increases exponentially. This directly causes cam 28 to become instantly and rigidly jammed with the F-shaped contact plate 8, forming a hard damping effect and triggering a series of problems such as brittle damage to the steel arch frame, secondary collapse of the surrounding rock, and cracking of structural components. At the same time, when the lift rate exceeds 0.12 mm / mm, cam 28 is prone to slippage, unable to continuously increase the compressive force, and the damping effect completely fails. When the lift rate is less than 0.06 mm / mm, the increase in protrusion height per unit arc length is too small, and the rate of increase in compressive force is extremely slow. It cannot provide sufficient frictional resistance within the effective pressure relief stroke of the steel arch frame, resulting in a severely insufficient damping effect. This fails to reduce the impact velocity of the upper steel arch frame, and ultimately, a strong hard collision still occurs.

[0034] To address the technical problem that during the actual production of various components, product precision or installation errors often prevent the fulfillment of the condition that "when the roller 29 just moves to the outer wall of the large square column 22, the outer wall of the cam 28 on both sides of it just touches the inner wall of the corresponding downward-moving F-shaped contact plate 8," thus failing to achieve precise contact between the cam 28 and the F-shaped contact plate 8 and failing to provide a damping effect on the upper steel arch frame 1, a precision contact unit is designed to solve the problem of inaccurate contact between the cam 28 and the F-shaped contact plate 8 and the failure of damping due to processing and installation errors.

[0035] like Figure 8 As shown, the precision contact unit includes a drive gear 34 coaxially mounted on the rod 33 and a spherical weight 39 welded to the end of the blocking rod 31. The drive gear 34 meshes with the upper end of the contact rack 35 welded to the top plate 4 (the contact rack 35 is a spur rack). A stop post 37 is also welded to the end of the extrusion post 26, and the stop post 37 is located directly below the rod 33. An annular weakening groove 36 is provided on the blocking rod 31 (the annular weakening groove is a V-shaped or U-shaped annular groove machined at the root of the blocking rod, serving as a predetermined fracture position), and the stop post 37 is located on the movement path of the annular weakening groove 36.

[0036] In actual operation, due to the precise contact unit, the process from the spherical weight 39 driving the cam 28 to rotate until the cam 28 contacts the F-shaped contact plate 8 requires a certain amount of time (albeit a short time). When the large square column 22 moves rapidly downwards due to centrifugal force, the compression spring 6 continuously slows down the rapidly downward-moving upper steel arch 1, causing the centrifugal force to continuously decrease and the descent speed of the large square column 22 to continuously slow down. Then, it moves upwards due to the elastic force of the first spring 24. This can easily lead to the first spring 24 causing the large square column 22 to move upwards during the period when the spherical weight 39 causes the cam 28 to contact the F-shaped contact plate 8, causing the cam 28 to separate from the roller 29, and subsequently failing to complete the contact and slowing down of the cam 28 and the F-shaped contact plate 8. Therefore, an anti-rebound locking unit is set to prevent the large square column 22 from rebounding under the action of the first spring 24, which would cause the precise contact unit to be interrupted and the slowing down to fail during the contact process.

[0037] like Figure 9 As shown, the anti-rebound locking unit includes a U-shaped plate bolted to the horizontal plate 25 and a U-shaped plate 41 integrally formed on the side of the large square column 22 (with a rectangular or circular lock hole). A locking post 40 is slidably installed on the U-shaped plate through a guide hole thereon, and one end of the locking post 40 is horizontally welded to the U-shaped plate through a locking spring 42. The other end of the locking post 40 is located below the U-shaped plate 41, and its upper end is provided with a pressing slope.

[0038] Working principle: Normal creep condition: Under normal conditions, when the upper steel arch 1 is slowly compressed by the surrounding rock, the upper steel arch 1 will move downward relative to the lower steel arch 2. Because it cannot generate a sufficiently large centrifugal force, the damping unit does not activate; instead, it uses four sets of relief springs 6 for pressure relief and buffering, achieving smooth pressure relief. Although the drive unit rotates the mounting plate 17, the generated centrifugal force is insufficient to overcome the preload of the first spring 24, and the detection trigger component does not activate. The final posture is that the support column 7 contacts the upper end of the base plate 3, completing the rigid limit of the pressure relief stroke. This process is suitable for slow, steady-state creep conditions of the surrounding rock.

[0039] Sudden Impact Conditions: When sudden impacts such as rockfall or rock bursts occur, the upper steel arch frame 1 will move rapidly downwards. This movement, via the rack and pinion 10, drives the large gear 11 to rotate. The large gear 11 then drives the small gear 12 to rotate rapidly. The rapid rotation of the small gear 12 will drive the rotating shaft 13 to rotate rapidly. The rotating shaft 13, through the meshing of the first bevel gear 14 and the second bevel gear 16, drives the mounting plate 17 to rotate rapidly. The centrifugal force generated by the rapid rotation of the mounting plate 17 causes the two sets of sliders 18 to move outwards against the tension of the first spring 24. This movement, via the movable rod 19, drives the rotating block 20 and the small square column 21 to move downwards.

[0040] As the large square column 22 moves downward, the lower end of the U-shaped plate 41 mounted on it abuts against the pressing slope of the locking column 40, causing the locking column 40 to press against the locking spring 42. This ultimately causes the end of the locking column 40 to move into the U-shaped opening of the U-shaped plate 41. After the roller 29 contacts the large square column 22, the end of the locking column 40 has entered the U-shaped opening of the U-shaped plate 41. When rebound occurs, the inner wall of the U-shaped opening abuts against the bottom of the locking column 40, forming a blockage. This prevents the large square column 22 from continuing to move upward. The roller 29 remains in contact with the outer wall of the large square column 22, preventing excessive rebound and separation of the roller 29 from the large square column 22.

[0041] Furthermore, the roller 29, which initially contacts the small square column 21, will press against the outer wall of the large square column 22 via the transition slope 23 (during this process, the extrusion column 26 will compress the second spring 30 outward). As the extrusion column 26 moves outward under the pressure of the transition slope 23, it drives the cam 28 to rotate through the meshing of the drive gear 34 and the abutting rack 35. Figure 10 As shown, cam 28 rotates counterclockwise. After the spherical weight 39 passes the central axis of cam 28, the drive gear 34 disengages from the contact rack 35. Subsequently, the cam 28 continues to rotate counterclockwise due to the gravity of the spherical weight 39, eventually causing cam 28 to press against the inner wall of the F-shaped contact plate 8.

[0042] It should be noted that when the spherical weight 39 continues to rotate counterclockwise and does not cross the central axis of the cam 28, the cam 28 can be made to stick tightly to the F-shaped contact plate 8 through the component force of the gravity of the spherical weight 39.

[0043] When the roller 29 just moves to the outer wall of the large square column 22, the outer wall of the cam 28 on both sides of it just abuts against the inner wall of the corresponding and downward moving F-shaped abutment plate 8 (or the abutment is completed with the assistance of the precision abutment unit).

[0044] Subsequently, the friction between cam 28 and F-shaped contact plate 8 causes cam 28 to rotate, thereby increasing the squeezing force between cam 28 and F-shaped contact plate 8. During this process, the reaction force of the squeezing force increases the squeezing force between roller 29 and the outer wall of large square column 22, which can perform bidirectional squeezing and limiting of large square column 22, keeping its position unchanged. This prevents the downward movement speed of upper steel arch frame 1 from decreasing due to the obstruction of cam 28 on upper steel arch frame 1, thus reducing the centrifugal force generated. This also prevents the large square column 22 from returning to its original position under the elastic force of the first spring 24, which would cause cam 28 to separate from F-shaped contact plate 8.

[0045] As the compressive force increases (the greater the compressive force, the better the damping effect), the lower ends of the two sets of F-shaped contact plates 8 bend outward to dampen the speed of the upper steel arch frame 1 (during this process, the compression spring 6 also provides damping). The outward deformation of the lower ends of the two sets of F-shaped contact plates 8 due to excessive compressive force is a necessary design feature—if they did not deform and resulted in hard compression, it would cause permanent damage to components such as the rod 33, the extrusion column 26, the roller 29, and the large square column 22 due to excessive impact force, making them unusable.

[0046] Throughout the braking process, as the cam 28 rotates, the compressive force between it and the F-shaped contact plate 8 increases, and the braking strength on the upper steel arch 1 per unit time increases. This gradually increasing braking strength causes the movement speed of the upper steel arch 1 to decrease smoothly, rather than abruptly, achieving flexible braking. This avoids both the instantaneous impact stress caused by rigidity and the hard collision caused by insufficient braking, ensuring that the stress change throughout the braking process remains within the elastic deformation range of the steel, protecting the steel arch 1 and the braking structure from damage.

[0047] Ultimately, this significantly reduces the collision between the upper steel arch frame 1 and the lower steel arch frame 2, thereby preventing irreversible damage to the steel arch frame and making the steel arch frame recyclable (the F-shaped contact plate 8 only needs to be replaced when reused).

[0048] When the spherical weight 39 continues to rotate counterclockwise and moves to the central axis position of the cam 28, its blocking rod 31 will contact the stop post 37 and form a compression, eventually causing the blocking rod 31 to break from the annular weakening groove 36. The spherical weight 39 separates from the blocking rod 31, preventing the spherical weight 39 from continuing to rotate counterclockwise and passing the central axis position of the cam 28, which would cause the spherical weight 39 to hinder the counterclockwise rotation of the cam 28 by gravity.

[0049] This support structure adds a self-opening damping protection mechanism to the basic support structure, which can achieve dual protection of "normal pressure relief + precise damping of sudden impact".

[0050] When a high-speed sudden impact occurs, the damping unit and the relief spring 6 work synchronously. The relief spring 6 absorbs the peak energy of the impact, and the cam 28 (made of wear-resistant alloy material) continuously consumes the remaining kinetic energy by squeezing and contacting the F-shaped contact plate 8 (the F-shaped contact plate 8 deforms due to contact), forming a secondary protection of "elastic buffer + deformation damping". It is suitable for extreme scenarios such as rock bursts and sudden collapse of surrounding rock, and its application range covers all types of tunnels from soft rock with large deformation to high ground stress impact.

[0051] After the impact condition ends, a comprehensive overhaul of the support structure is performed. Since the blocking rod 31 has broken at the annular weakening groove 36, a new blocking rod 31 (along with the spherical weight 39) needs to be replaced, along with the potentially worn F-shaped contact plate 8 and cam 28. The locking pin 40 is manually pulled out of the retaining plate 41, and the large square pin 22 is pushed upwards to reset the first spring 24; the compression pin 26 is pushed inwards to reset the second spring 30. After resetting, the support structure can be put back into use, achieving reuse.

[0052] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0053] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0054] Additionally, "multiple" refers to two or more.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A tunnel support structure, comprising an upper steel arch frame (1) and a lower steel arch frame (2) for fitting against the inner wall of the tunnel and supporting the surrounding rock, wherein a bottom plate (3) and a top plate (4) are respectively provided on the opposing end faces of the upper steel arch frame (1) and the lower steel arch frame (2), and a pressure-relief component for adapting to the slow steady-state creep condition of the surrounding rock is provided between the bottom plate (3) and the top plate (4), characterized in that, Also includes: The self-starting damping protection mechanism includes a detection trigger component for converting the speed of movement of the upper steel arch frame (1) into the magnitude of centrifugal force and automatically triggering the damping function when the centrifugal force is greater than a set value, and a damping unit disposed on the base plate (3) for damping the upper steel arch frame (1) moving rapidly downward.

2. The tunnel support structure according to claim 1, characterized in that: The detection triggering component includes a drive unit located between the bottom plate (3) and the top plate (4) and transmitting force under the rapid movement of the upper steel arch frame (1), and a centrifugal detection unit for triggering the damping unit and driven by the drive unit.

3. The tunnel support structure according to claim 2, characterized in that: The lower steel arch frame (2) has two guard plates (5) fixed at both ends. The guard plates (5) have openings for the upper steel arch frame (1) to move down and slide to connect with the corresponding part of the upper steel arch frame (1). The centrifugal detection unit includes a horizontal plate (25) fixed between the two guard plates (5) and a mounting plate (17) located on the lower side of the horizontal plate (25) and rotating horizontally. Two sliders (18) slide separately along their radial lines on the mounting plate (17). Each slider (18) is rotatably provided with a movable rod (19). The two movable rods (19) are rotatably provided with the same rotating block (20) at their close ends. A small square column (21) is rotatably provided on the rotating block (20). The small square column (21) passes through the end face of the horizontal plate (25) and moves vertically. The upper end of the small square column (21) is formed into a large square column (22) by a transition slope (23). The outer wall of the large square column (22) is provided with a first spring (24) connected to the horizontal plate (25).

4. A tunnel support structure according to claim 3, characterized in that: The damping unit includes mounting plates (27) arranged opposite to each other on both sides of the small square column (21), and two F-shaped abutment plates (8) with flexible and deformable lower ends fixed to the front and rear ends of the upper steel arch frame (1) and fixedly connected to the bottom plate (3). A compression column (26) is horizontally slidably arranged on the mounting plate (27), and the compression column (26) is fixedly connected to the mounting plate (27) by a second spring (30). The compression column (26) is provided with a corresponding end of the small square column (21). A roller (29) adapted to and abuts against the transition slope (23), and a rod (33) is rotatably provided at the other end of the extrusion column (26). Multiple sets of cams (28) are provided on the rod (33), and a long arc-shaped protrusion is provided on the periphery of the cam (28). Multiple sets of cams (28) are connected by connecting rods (38). A blocking rod (31) is eccentrically provided on the outermost cam (28), and the blocking rod (31) contacts the stop block (32) provided at the end of the extrusion column (26). As the small square column (21) moves downward, the roller (29) smoothly passes through the transition slope (23) and contacts the outer wall of the large square column (22), causing the extrusion column (26) to move outward horizontally under the support of the second spring (30). At the same time, the cam (28) contacts the inner wall of the downward-moving F-shaped contact plate (8) and rotates, transmitting the gradually increasing frictional extrusion force between the cam (28) and the F-shaped contact plate (8) and the limiting and holding effect of the stop rod (31) and the stop block (32), causing the lower end of the F-shaped contact plate (8) to bend and deform outward and form a gradual resistance to the upper steel arch frame (1).

5. A tunnel support structure according to claim 3, characterized in that: The drive unit includes a rack (10) fixedly mounted on the base plate (3), a large gear (11) rotatably mounted on the top plate (4) and adapted to be connected to the rack (10), and a small gear (12) located on one side of the large gear (11) and adapted to be connected to the large gear (11). A rotating shaft (13) passes through the end face of the small gear (12). A first bevel gear (14) is fixed at one end of the rotating shaft (13) away from the small gear (12). A second bevel gear (16) is adapted to be mounted on the first bevel gear (14). The second bevel gear (16) is coaxially mounted with the mounting plate (17) and mounted on the top plate (4) through a fixing bracket (15). The upper steel arch frame (1) moves rapidly downward, causing the rack (10) to drive the large gear (11) to rotate. The torque transmitted through the small gear (12) and the rotating shaft (13) drives the first bevel gear (14) to rotate at an increased speed. Under the transmission action of the first bevel gear (14) and the second bevel gear (16), the mounting plate (17) rotates at high speed, transmitting centrifugal force to make the two sliders (18) slide outward. Then, under the action of the movable rod (19) and the rotating block (20), the small square column (21) moves downward.

6. A tunnel support structure according to claim 4, characterized in that: A stop post (37) is provided at the end of the extrusion post (26) and on the lower side of the rod (33). The rod (33) is provided with a precise contact unit for controlling and realizing the contact between the cam (28) and the surface of the F-shaped contact plate (8) at the beginning; The precision abutment unit includes a drive gear (34) coaxially mounted on the rod (33), an abutment tooth (35) adapted to the drive gear (34) and fixed on the top plate (4), a spherical weight (39) is provided at the end of the blocking rod (31) away from the cam (28), and an annular weakening groove (36) is provided at the other end of the blocking rod (31), and the movement path of the annular weakening groove (36) passes through the stop post (37). When the extrusion column (26) passes through the transition slope (23) and moves outward under the pressure of the outer wall of the large square column (22), the drive gear (34) meshes with the abutting rack (35) to drive the cam (28) to rotate; after the drive gear (34) disengages from the abutting rack (35), the cam (28) continues to rotate under the gravity of the spherical weight (39) until it abuts against the F-shaped abutting plate (8); and when the blocking rod (31) is squeezed by the stop column (37), the blocking rod (31) breaks from the annular weakening groove (36), causing the spherical weight (39) to separate from the cam (28).

7. A tunnel support structure according to claim 6, characterized in that: The horizontal plate (25) is provided with an anti-rebound locking unit for limiting and locking the large square column (22); The anti-rebound locking unit includes a U-shaped plate fixed on the horizontal plate (25) and spaced apart on the side of the large square column (22) and a spiral plate (41) extending on the side of the large square column (22). A locking post (40) is slidably disposed on the U-shaped plate and moves linearly toward the spiral plate (41) and presses against it. A locking spring (42) is horizontally fixed on the locking post (40) at the inner end of the U-shaped plate.

8. A tunnel support structure according to claim 4, characterized in that: The outer wall of the F-shaped contact plate (8) is provided with multiple sets of reinforcing plates (9) arranged side by side, and the reinforcing plates (9) are right-angled triangular structures with a bottom wider than the top.

9. A tunnel support structure according to claim 3, characterized in that: The pressure relief assembly includes multiple sets of pressure relief springs (6) arranged evenly between the bottom plate (3) and the top plate (4) for support. Each pressure relief spring (6) has a support column (7) coaxially arranged inside it and fixed on the top plate (4). The upper end of the support column (7) does not contact the bottom plate (3) and leaves a clearance space. The upper horizontal plane of the support column (7) is located above the end face of the large square column (22).

10. A tunnel support method, employing a tunnel support structure as described in any one of claims 1-9, characterized in that, Specifically, the steps include the following: S1, Conventional creep relief: In the scenario of slow steady creep of the surrounding rock, the upper steel arch frame (1) is smoothly relieved by the relief spring (6), the self-starting damping protection mechanism is not activated, and the rigid limit of the relief stroke is completed by the support column (7). S2, sudden impact mitigation: In the case of sudden collapse of surrounding rock and rock burst causing the upper steel arch frame (1) to move rapidly downward, the self-starting mitigation protection mechanism is activated to form a secondary collaborative protection and smoothly consume the impact kinetic energy; S3, Reset and Reuse: After the impact condition ends, the support structure is fully inspected and vulnerable parts are replaced. The motion mechanism is reset and parameters are recalibrated to enable the reuse of the support structure.

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