Supporting structure for resisting tunnel rockburst and construction method thereof

Abstract

The invention relates to the technical field of tunnel supporting, in particular to a supporting structure for resisting tunnel rockburst and a construction method of the supporting structure, and aims to solve the problem that in the prior art, after a supporting structure is subjected to rockburst impact, the supporting strength is not enough, and a single position is easily damaged. Comprising a plurality of reinforced nets, supporting ropes and a plurality of anchoring bodies, and each anchoring body comprises a lantern ring and a fixing shaft; primary spraying concrete is sprayed on the inner wall of the tunnel, the reinforced net is laid on the surface of the primary spraying concrete, the supporting rope penetrates through the lantern ring and the reinforced net along the inner wall of the tunnel, the fixing shaft is connected with a fixing cylinder, the lantern ring is connected with a supporting cylinder, and the supporting cylinder is used for improving the supporting strength of the reinforced net. The anchoring body and the reinforced net are beneficial to introducing stress into the reinforced net surface, the supporting strength is improved, and the risk of single-point snapping is reduced; and the lantern ring and the fixing shaft are convenient to position, pour and fix in the drill hole, so that the mounting stability and the construction convenience are improved.

Description

Technical Field

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

[0002] As transportation, water conservancy, and energy projects develop towards deeper and ultra-deep burial, the geological environment of tunnel projects is becoming increasingly complex. Especially under high ground stress conditions, the surrounding rock is prone to sudden damage phenomena such as rock bursts, spalling, and spalling under the effects of excavation unloading and stress redistribution. Rock bursts are characterized by high energy, short duration, and violent forms of damage, often causing instantaneous impacts on existing support structures, seriously threatening construction safety and project stability.

[0003] Currently, for the support of surrounding rock in high-stress tunnels, engineering projects commonly employ a combined support system mainly composed of anchor bolts, anchor cables, steel mesh, and shotcrete. Among these, anchor bolts are mostly integral metal rods or hollow grouting anchor bolts, which connect the surrounding rock to the deeper stable rock mass through end anchoring or full-length bonding, thereby improving the overall bearing capacity of the surrounding rock. Simultaneously, steel mesh or metal mesh is used to constrain the surface of the surrounding rock, and shotcrete is used to form a surface reinforcement structure.

[0004] However, the aforementioned traditional support systems still have significant shortcomings in dealing with high-energy dynamic disasters such as rockbursts. First, existing anchor structures are mainly rigid or quasi-rigid, with a design focus on improving load-bearing capacity, while insufficient consideration is given to the absorption and dissipation of impact energy. This makes them prone to failure modes such as anchor breakage, anchoring failure, or large-scale spalling of shotcrete during rockbursts. Second, existing anchors and support meshes are usually connected by simple binding, welding, or rigid methods. These methods are difficult to redistribute stress under dynamic impact, and local failure can easily induce cascading damage. Third, existing support structures have long construction times (5-7 hours), making it difficult to quickly seal off rockburst areas, and the sealing process is prone to safety risks such as flying rocks and ricochets. Furthermore, the steel mesh used is 8mm in diameter and 25cm×25cm in size, which is relatively large. Moreover, the welding quality is easily affected by subjective human factors, which means that it cannot effectively resist flying rocks and projectile impacts when moderate or strong delayed rock bursts occur, making it prone to damage. Fourth, due to safety concerns about rock bursts during construction, a combined support method of "shotcrete, double-layer steel mesh, system anchor bolts and re-shotcrete" is uniformly adopted regardless of the strength, resulting in over-support, extended construction period, increased costs and waste of resources.

[0005] Furthermore, existing support systems generally lack the ability to respond to and record rockburst impact processes. After experiencing impact loads, anchor bolts and their connecting components typically only show whether they have broken or fallen off, failing to reflect the impact energy level and stress history experienced by the surrounding rock. This makes it impossible for construction personnel to effectively assess the evolution of surrounding rock stability afterward, and also makes it difficult to take timely and targeted reinforcement or adjustment measures, posing certain safety hazards. Summary of the Invention

[0006] The purpose of this invention is to provide a support structure and its construction method for resisting tunnel rockbursts, so as to solve the above-mentioned problems.

[0007] The first aspect of the present invention is achieved by the following technical solution: A support structure for tunnel rockburst, comprising: Several reinforcing meshes; Several support ropes, with tensioning components provided at both ends of the support ropes along their length; Several anchor bodies are formed by bending a steel wire rope 180° at its midpoint along its own axis. The anchor body forms a loop at the bend. The two sides of the loop are fixed shafts. Several boreholes are opened in the inner wall of the tunnel. The fixed shafts are located inside the boreholes, and the loops are located outside the boreholes. Cement grout is poured into the boreholes. Several anchor bodies are equidistantly arranged on the reinforcing mesh. A support cylinder is detachably connected to a collar, and a base is connected to the bottom of the support cylinder. The base and the support cylinder are used to clamp the mesh of the reinforcing mesh. The tunnel's inner wall is sprayed with initial shotcrete. Adjacent reinforcing meshes are connected to each other by rope clamps and laid on the surface of the initial shotcrete along the circumferential direction of the tunnel. Several support ropes are equidistantly threaded through loops along the tunnel's axial direction to abut against the reinforcing meshes. A fixing cylinder is connected to the fixing shaft. The fixing cylinder is used to increase the anchoring strength of the fixing shaft. The support cylinder is used to enhance the support strength of the reinforcing meshes and transmits the impact force to adjacent support cylinders through connectors.

[0008] In the above technical solution, the combination of the anchor body and the reinforcing mesh is beneficial to introduce the force into the surface of the reinforcing mesh, realize the force distribution, and reduce the risk of single-point breakage; the loop and fixed shaft formed by bending the wire rope are convenient for positioning and casting fixation in the borehole, improving installation stability and construction simplicity; the support cylinder can improve the support strength of the reinforcing mesh and anchor body in the local area.

[0009] In some optional technical solutions, a sliding groove is provided on the inner peripheral wall of the fixed cylinder, a limiting ring is slidably connected in the sliding groove, a retaining strip is connected to the end of the sliding groove, the retaining strip can rotate outward along the sliding groove, a through hole is passed through the middle of the limiting ring, and the fixed shaft passes through the through hole and is connected to the limiting ring.

[0010] In the above technical solution, during the grouting process, the anchor body automatically unfolds the locking strip through the moving limiting ring to achieve reverse locking, thereby increasing the anchoring strength.

[0011] In some alternative technical solutions, the bottom of the limiting ring is connected to a connecting cylinder, the cavity of the connecting cylinder is connected to the through hole, and a retaining ring is detachably connected to the fixed shaft for connecting with the connecting cylinder.

[0012] In the above technical solution, the geometric relationship between the radius of the limiting ring and the clip ensures that the clip has a sufficient angle of expansion when it is pulled to insert into the grout and form a mechanical engagement. The solidification of the cement grout is used to achieve secondary anchoring, thereby improving the reliability of the anchoring.

[0013] In some optional technical solutions, a shaft is fixedly connected to the bottom surface of the support cylinder, there is a gap between the shaft and the inner wall of the support cylinder, a connecting hole is opened on the top surface of the support cylinder, a transition hole is opened on the shaft in the radial direction, a buckle is provided on the side of the inner wall of the support cylinder away from the connecting hole, and the collar is sleeved on the buckle along the connecting hole and through the transition hole.

[0014] In the above technical solution, the collar is fitted onto the buckle after passing through the transition hole, forming a U-shaped bend on the shaft, so that the collar and the fixed shaft are not on the same axis. When a rockburst occurs, the entire anchor body is not vertical, but forms a U-shaped bend at the transition hole, and the impact force of the rockburst is dispersed by the shaft.

[0015] In some optional technical solutions, a guide rail is provided inside the wall of the support cylinder, and a slider is slidably connected to the guide rail. An annular groove is provided at the bottom of the shaft, and a rotating shaft is rotatably connected inside the annular groove. A spiral groove is provided on the outer peripheral wall of the rotating shaft. A guide rod is connected to the inner peripheral wall of the slider, and the end of the guide rod is slidably connected to the groove. An insertion hole is provided through the slider, and the support rope passes through the insertion hole and passes through a collar through a transition hole inside the support cylinder.

[0016] In the above technical solution, the support cylinder can break the easily broken shaft when a certain load is reached, the slider slides down and drives the rotating shaft to rotate, and the rotating shaft drives the reinforcing mesh to rotate synchronously, thereby improving the tension of the reinforcing mesh and the support strength.

[0017] In some alternative technical solutions, a breakable shaft is connected to the outer peripheral wall of the shaft, and the other end of the breakable shaft is connected to the inner peripheral wall of the slider.

[0018] In the above technical solution, the fracturing shaft is used to restrict the slider from sliding down due to inertia. Only when a rock burst occurs and the fracturing shaft breaks can the slider slide down.

[0019] In some alternative technical solutions, the connector is a flexible connecting rope, and every four sliders are connected sequentially by the connecting rope along the length of the reinforcing mesh.

[0020] In the above technical solution, when a rockburst occurs in a certain area, if the rockburst impact is strong, after the slider of a support cylinder falls, it will drive the connected sliders to fall together through the connecting rope, thus avoiding the risk of large damage to a single point.

[0021] In some optional technical solutions, the base is connected to a number of locking pins on the side facing the shaft, and the rotating shaft is provided with a number of locking holes on the side facing the base for engaging with the locking pins. When the slider is sliding or stationary, the end of the rotating shaft near the base is always located outside the slider.

[0022] In the above technical solution, the base is fixed by a locking pin and a locking hole of the rotating shaft. The two clamp the reinforcing mesh, and the rotating shaft rotates to drive the reinforcing mesh to rotate and increase the tension.

[0023] In some optional technical solutions, the surface of the initial shotcrete is also sprayed with secondary shotcrete, and the surface of the secondary shotcrete is covered with several geotextiles and waterproof membranes. Several detachable fixing clips are equidistantly arranged on the two fixing shafts of the anchor body.

[0024] In the above technical solution, the waterproof membrane and geotextile protect the initial shotcrete layer from moisture, erosion and secondary damage during construction, improving the integrity and lifespan of the coating layer; the equidistantly arranged fixing clips improve the stress distribution, prevent local shear concentration, and enhance the connection durability.

[0025] A second aspect of the present invention provides a construction method for a tunnel rockburst support structure, wherein the tunnel is constructed based on the support structure described in the first aspect of the present invention, comprising the following steps: S1. Excavate and remove slag, remove hazards from the rock surface, prepare the wet spraying trolley, and spray initial shotcrete onto the tunnel rock surface. S2. Lay reinforcing mesh; S3. Drill holes to install the anchor body and inject cement grout to fix it; S4. After repeating the construction cycles of S1 to S3 several times, install the support rope and support cylinder through the collar. S5. Inspection of safety status of tunnel rockburst; S6. Dismantle the support cylinder, re-spray concrete, and install geotextile and waterproof membrane in sequence, followed by secondary lining concrete construction.

[0026] In some alternative technical solutions, in S2, several reinforcing meshes are laid along one side of the tunnel arch foot toward the arch crown and then close to the surface of the initial shotcrete in S1. The mesh surface of the reinforcing meshes is fixed to the surface of the initial shotcrete with U-shaped steel clips. Adjacent reinforcing meshes are fixed to each other by rope clips. 50cm of length is left on each side of the tunnel arch foot for the reinforcing mesh to wrap around.

[0027] In some optional technical solutions, step S3 further includes the following steps: S31. Drill holes into the surface of the initial sprayed concrete through the mesh of the reinforcing mesh, and clean the drill holes; S32. Fold the wire rope along its own axial direction to form an anchor body; repeat the preparation of anchor bodies until the required number is reached. S33. Insert the two fixed shafts of each anchor body into the two fixed cylinders respectively; S34. The two fixed shafts of the anchor body are brought close together and fixed by the fixing clamp, which is located between the collar and the fixing cylinder of the anchor body. S35. Insert the fixed shaft of the anchor body into the borehole and inject cement grout into the borehole.

[0028] In some alternative technical solutions, in S33, after the fixed shaft passes through the through hole of the limiting ring, the retaining ring is installed on the shaft body of the fixed shaft and connected to the connecting cylinder; in S35, after the cement grout has submerged the fixed cylinder, the collar of the anchor body is pulled into the tunnel, the fixed shaft drives the limiting ring to move, the limiting ring pushes the retaining strip to unfold and insert into the cement grout, and then the cement grout continues to be injected until the borehole is filled.

[0029] In some optional technical solutions, step S4 further includes the following steps: S41. Place the support sleeve at the collar position of the anchor body; S42. The end of the support cylinder furthest from the slider is inserted into the cement grout, while the other end is exposed inside the tunnel; S43. Adjust the length of the support cylinder inserted into the cement grout until the collar of the anchor body contacts the slider.

[0030] In some optional technical solutions, in S5, within a set period after the construction in S4, the position and status of the support cylinder inside the tunnel are observed: When the slider inside the support cylinder does not slide out, it indicates that the area where the support cylinder is located is safe and qualified. When the slider inside the support cylinder slides out, it indicates that a rock burst has occurred in the area where the support cylinder is located, and the support strength in the area where the support cylinder is located needs to be increased; in S6, after the set cycle is reached, the support cylinder is removed or sheared, and sprayed with sprayed concrete on the surface of the initial sprayed concrete. Geotextile and waterproof membrane are installed on the surface of the sprayed concrete in sequence, and finally, secondary lining concrete is constructed on the surface of the waterproof membrane.

[0031] In the above technical solution, Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. In this invention, through the synergistic effect of steel wire rope bent into an anchor body, multiple reinforcing meshes, several support ropes and shotcrete, a composite support structure with both flexible energy absorption and rigid constraint is constructed on the tunnel rock surface, so that the impact energy is gradually dispersed and dissipated within and inside the reinforcing mesh, significantly reducing the risk of instantaneous fracture at a single point. 2. The fixing cylinder in this invention can unfold the locking strip in the cement grout during the process of inserting the anchor body into the borehole and injecting cement grout, and mechanically engage with the grout, thereby improving construction efficiency and anchoring strength. 3. When the support cylinder of the present invention is subjected to impact, the internal easily broken shaft breaks, the slider slides, and drives the rotating shaft to rotate. The rotating shaft then drives the reinforcing mesh clamped with the base to rotate synchronously, thereby increasing the tension of the reinforcing mesh and thus increasing the support strength of the reinforcing mesh. Attached Figure Description

[0032] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram showing the installation position of the support structure of the present invention in a tunnel; Figure 2 This is a schematic diagram showing the relative positions of the support structures of the present invention; Figure 3 This is a schematic diagram of the anchor body in this invention; Figure 4 This is a schematic diagram of the structure of the anchor body and the support cylinder in this invention; Figure 5 This is a schematic diagram of the structure of the fixed cylinder in this invention; Figure 6 This is a cross-sectional view of the support cylinder in this invention. Figure 1 ; Figure 7 This is a cross-sectional view of the middle support cylinder in this invention. Figure 2 ; Figure 8 This is a schematic diagram showing the connection between the collar, support rope, and reinforcing mesh and the support cylinder in this invention; Figure 9 This is an exploded view of the support cylinder in this invention.

[0033] The reference numerals in the attached figures represent: 1. Reinforcing mesh; 2. Support rope; 3. Anchor body; 31. Collar; 32. Fixed shaft; 4. Fixed cylinder; 41. Limiting ring; 42. Clamping ring; 43. Clamping claw; 5. Support cylinder; 51. Sliding block; 511. Guide rod; 512. Connecting rope; 52. Easily broken shaft; 53. Insertion hole; 54. Rotating shaft; 541. Groove; 55. Base; 56. Shaft; 561. Transition hole; 57. Connecting hole; 58. Buckle; 6. Initial shotcrete. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are for illustrative purposes only and are not intended to limit the invention. It should be noted that this invention is already in the actual research and development stage.

[0035] Example 1: like Figures 1 to 8 As shown, this embodiment provides a support structure for tunnel rockburst, comprising: Several reinforced mesh 1; Several support ropes 2, with tensioning components at both ends of the support ropes 2 along their length; Several anchor bodies 3 are formed by bending a steel wire rope 180° at its midpoint along its own axis. An anchor body 3 forms a ring 31 at the bend. The two sides of the ring 31 are fixed shafts 32. Several boreholes are opened in the inner wall of the tunnel. The fixed shafts 32 are located inside the boreholes, and the ring 31 is located outside the boreholes. Cement grout is poured into the boreholes. Several anchor bodies 3 are equidistantly arranged on the reinforcing mesh 1. The support cylinder 5 is detachably connected to the collar 31. The bottom of the support cylinder 5 is connected to the base 55, and the base 55 and the support cylinder 5 are used to clamp the mesh of the reinforcing mesh 1. In this process, initial shotcrete 6 is sprayed onto the inner wall of the tunnel. Adjacent reinforcing mesh 1 is connected to each other by rope clamps and laid on the surface of the initial shotcrete 6 along the circumferential direction of the tunnel. Several support ropes 2 are equidistantly threaded through collars 31 along the axial direction of the tunnel and abut against the reinforcing mesh 1. A fixing cylinder 4 is connected to the fixing shaft 32. The fixing cylinder 4 is used to increase the anchoring strength of the fixing shaft 32. The support cylinder 5 is used to enhance the support strength of the reinforcing mesh 1 and transmits the impact force to the adjacent support cylinder 5 through the connector.

[0036] like Figures 3 to 5 As shown, a sliding groove is provided on the inner peripheral wall of the fixed cylinder 4, and a limit ring 41 is slidably connected in the sliding groove. A retaining strip is connected to the end of the sliding groove, and the retaining strip can rotate outward along the sliding groove. A through hole is provided in the middle of the limit ring 41, and the fixed shaft 32 passes through the through hole and is connected to the limit ring 41.

[0037] like Figures 3 to 5As shown, there is a gap between the end of the slide groove and the bottom of the fixed cylinder 4. The radius of the limiting ring 41 is greater than the distance from the inner wall of the clip to the center of the fixed cylinder 4. The bottom of the limiting ring 41 is connected to a connecting cylinder. The cavity of the connecting cylinder and the through hole are connected. A retaining ring 42 is detachably connected to the fixed shaft 32. The retaining ring 42 is used to connect with the connecting cylinder.

[0038] Specifically, after the tunnel is excavated and cleaned, initial shotcrete 6 is sprayed onto the tunnel rock surface. After it solidifies, a reinforcing mesh 1 is laid on the surface of the initial shotcrete 6. The reinforcing mesh 1 is laid along the arch foot on one side of the tunnel to the arch top on the other side. The reinforcing mesh 1 needs to be attached to the tunnel arch top with steel buckles. Then, holes are drilled into the initial shotcrete 6 and the tunnel rock surface for inserting anchor bodies 3 into the holes.

[0039] It should be noted that the anchor body 3 of the present invention is formed by bending a steel wire rope along its own axial midpoint. The anchor body 3 has the same function as the anchor rod. After bending, the anchor body 3 forms a collar 31 at the bend. The steel wire ropes at both ends of the collar 31 serve as fixed shafts 32. When the anchor body 3 is inserted into the drill hole, the fixed shaft 32 is located inside the drill hole, and the collar 31 is located outside the drill hole. At the same time, after the anchor body 3 is inserted into the drill hole, cement grout is injected into the drill hole for fixation. Finally, the reinforcing mesh 1 and the anchor body 3 are connected and fixed by the support rope 2. When the support rope 2 passes through the mesh surface of the reinforcing mesh 1, it will also pass through the collar 31 of the anchor body 3 to achieve connection and fixation.

[0040] To increase the anchoring strength of the anchor body 3, after the wire rope is bent into the anchor body 3, the fixed shaft 32 passes through the through hole of the limiting ring 41, and the retaining ring 42 is also sleeved on the fixed shaft 32. The retaining ring 42 is rotated to connect with the connecting cylinder by threads, so that the fixed shaft 32 is fixed to the limiting ring 41. Preferably, in order to facilitate the fixing of the fixed shaft 32, the retaining ring 42 itself is two detachably connected semi-circular rings that can be interlocked without affecting the external thread. The retaining ring 42 is interlocked with the fixed shaft 32 near the connecting cylinder, and then the fixed shaft 32 is screwed into the connecting cylinder.

[0041] Next, after the anchor body 3 is inserted into the borehole, cement grout is injected to the bottom of the fixing cylinder 4. The top of the fixing cylinder 4 is held in place by a rod-shaped tool, and grouting continues until the fixing cylinder 4 is submerged. Then, the collar 31 is pulled outward, and the fixing shaft 32 of the anchor body 3 drives the limiting ring 41 to slide along the groove. When the limiting ring 41 slides, it will abut against the retaining strip. The retaining strip is squeezed and opens outward to insert into the cement grout. At the same time, the cement grout in the borehole will also seep into the groove. The limiting ring 41 cannot be reset due to the limitation of the fixing shaft 32 and the cement grout. At this time, all retaining strips have been fully opened, which can effectively improve the anchoring strength of the anchor body 3. Finally, the borehole is completely filled with cement grout.

[0042] Example 2: A shaft 56 is fixedly connected to the bottom surface of the support cylinder 5. There is a gap between the shaft 56 and the inner wall of the support cylinder 5. A connecting hole 57 is opened on the top surface of the support cylinder 5. A transition hole 561 is opened in the radial direction of the shaft 56. A buckle 58 is provided on the side of the inner wall of the support cylinder 5 away from the connecting hole 57. The collar 31 is sleeved on the buckle 58 through the transition hole 561 along the connecting hole 57.

[0043] like Figures 6 to 9 As shown, a guide rail is provided inside the support cylinder 5, and a slider 51 is slidably connected to the guide rail. An annular groove is provided at the bottom of the shaft 56, and a rotating shaft 54 ​​is rotatably connected inside the annular groove. A spiral groove 541 is provided on the outer peripheral wall of the rotating shaft 54. A guide rod 511 is connected to the inner peripheral wall of the slider 51, and the end of the guide rod 511 is slidably connected inside the groove 541. An insertion hole 53 is passed through the slider 51, and the support rope 2 passes through the insertion hole 53 and passes through the transition hole 561 inside the support cylinder 5 to pass through the collar 31.

[0044] like Figures 6 to 9 As shown, a breakable shaft 52 is connected to the outer peripheral wall of the shaft 56, and the other end of the breakable shaft 52 is connected to the inner peripheral wall of the slider 51.

[0045] The base 55 is connected to several locking pins on the side facing the shaft 56, and the rotating shaft 54 ​​is provided with several locking holes on the side facing the base 55 for engaging with the locking pins. When the slider 51 is sliding or stationary, the end of the rotating shaft 54 ​​near the base 55 is always located outside the slider 51.

[0046] The surface of the initial shotcrete 6 is also sprayed with secondary shotcrete, and several geotextiles and waterproof membranes are installed on the surface of the secondary shotcrete.

[0047] Several detachable fixing clips are equidistantly arranged on the two fixed shafts 32 of the anchor body 3.

[0048] Specifically, after the anchor body 3, reinforcing mesh 1, and support rope 2 are installed, a support cylinder 5 will be installed at the collar 31 of the anchor body 3. The collar 31 must first pass through the connecting hole 57 and then through the transition hole 561, and finally be fixed on the buckle 58. The support cylinder 5 has a guide rail, and the slider 51 is slidably connected to the guide rail. The side of the support cylinder 5 near the connecting hole 57 can be inserted into the uncured cement grout. The slider 51 is blocked by the easily broken shaft 52 and cannot slide. It should be noted that all anchor bodies 3 are installed in a ring along the tunnel, that is, the anchor body 3 is in an inclined state, and the collar 31 above the arch foot always faces downward.

[0049] After the anchor body 3, reinforcing mesh 1, and support rope 2 are installed, a certain period of waiting will be required. During this waiting period, if a rock burst occurs in a certain area of ​​the tunnel, the anchor body 3 will provide buffer support to that area through the support rope 2 and the reinforcing mesh 1. However, the impact vibration is unavoidable. When the anchor body 3 is impacted, it will be transmitted to the support cylinder 5. The fragile shaft 52 inside the support cylinder 5 is thin and fragile. It will break after being impacted. After the fragile shaft 52 breaks, the slider 51 is no longer limited and will slide down along the guide rail. The guide rail has a limited length, so the slider 51 does not fall completely outside the support cylinder 5 to avoid injuring people or damaging the initial shotcrete 6.

[0050] After passing through the transition hole 561, the collar 31 is fitted onto the buckle 58, forming a U-shaped bend on the shaft 56, so that the collar 31 and the fixed shaft 32 are not on the same axis. When a rock burst occurs, the entire anchor body 3 is not vertical, but forms a U-shaped bend at the transition hole 561, and disperses the impact force of the rock burst with the help of the shaft 56.

[0051] When the slider 51 of a certain support cylinder 5 slips, it indicates that a rockburst has occurred in that area. The fragile shaft 52 breaks, the slider 51 loses its limit, and falls rapidly due to the impact force of the rockburst and its own inertia. During the fall, the slider 51 will cooperate with the groove 541 of the rotating shaft 54 ​​through the guide rod 511. The rotating shaft 54 ​​is rotatably connected to the bottom of the shaft 56 and cannot move axially on its own. When pushed by the axially moving guide rod 511, it rotates along the shaft 56 with the help of the spiral groove 541. The base 55 is engaged with the locking hole at the bottom of the rotating shaft 54 ​​through the locking pin. When the rotating shaft 54 ​​rotates, it will also drive the base 55 to rotate synchronously. The rotating shaft 54 ​​and the base 55 together hold the mesh of the reinforcing mesh 1. The reinforcing mesh 1 is flexible. When the rotating shaft 54 ​​rotates, it will drive the reinforcing mesh 1 at that location to rotate synchronously, increasing the local tension of the reinforcing mesh 1, thereby increasing the support strength of the reinforcing mesh 1.

[0052] When slider 51 falls, it also proves that a rockburst has occurred. Construction workers can judge whether a rockburst has occurred based on whether slider 51 falls, and whether the support structure needs to be strengthened or maintained. If slider 51 is not exposed or falls, it indicates that everything is normal. Afterwards, the support cylinder 5 can be cut with the help of tools, and the part outside the initial shotcrete 6 can be cut off. Preferably, the shaft 56 itself can be divided into two sections and threadedly connected, including a first connecting section above the transition hole 561 and a second connecting section below the transition hole 561. This makes it easy to unscrew the second connecting section for recycling after cutting the support cylinder 5. The first connecting section and the support cylinder 5 are fixed in the cement slurry. If slider 51 and the easily broken shaft 52 are intact, they can be used in the next construction area, which is not wasteful. Finally, spray shotcrete on the initial shotcrete 6, and install waterproof membrane and geotextile on the shotcrete.

[0053] Example 3: like Figures 6 to 9 As shown, the connector is a flexible connecting rope 512. Along the length of the reinforcing mesh 1, every four sliders 51 are connected in sequence by the connecting rope 512.

[0054] Specifically, when a rockburst occurs in a certain area, if the rockburst impact is strong, after the slider 51 of one support cylinder 5 falls, it will drive the connected slider 51 to fall together through the connecting rope 512. That is, the impact force that originally had to be borne by one support cylinder 5 and the connected reinforcing mesh 1 is now borne by multiple support cylinders 5 and reinforcing mesh 1, reducing the force borne by each support cylinder 5 and each reinforcing mesh 1, and avoiding damage caused by excessive impact on a single point.

[0055] Example 4: like Figures 1 to 9 As shown, a construction method for a tunnel rockburst support structure is used to construct a tunnel based on the support structures of Examples 1 to 3, including the following steps: S1. Excavate and remove slag, remove hazards from the rock surface, prepare the wet spraying trolley, and spray initial shotcrete onto the tunnel rock surface. S2, Lay the reinforcing mesh 1; S3. Drill holes to install anchor body 3, and inject cement grout to fix it; S4. After repeating the construction cycles of S1 to S3 for several cycles, install the support rope 2 and the support cylinder 5 through the collar 31. S5. Inspection of safety status of tunnel rockburst; S6. Dismantle support cylinder 5, spray concrete again and install geotextile and waterproof membrane in sequence, and then carry out secondary lining concrete construction.

[0056] In S2, several reinforcing meshes 1 are attached to the surface of the initial shotcrete 6 in S1 along one side of the tunnel arch foot towards the arch top and the other side arch foot. The mesh surface of the reinforcing meshes 1 is fixed to the surface of the initial shotcrete 6 with U-shaped steel clips. Adjacent reinforcing meshes 1 are fixed to each other by rope clamps. 50cm of length is left on each side of the tunnel arch foot for the reinforcing meshes 1 to wrap around.

[0057] S3 also includes the following steps: S31. Drill holes into the surface of the initial sprayed concrete 6 through the mesh of the reinforcing mesh 1, and clean the drill holes; S32. Fold the wire rope along its own axial direction to form the anchor body 3; repeat the preparation of anchor bodies 3 until the required number is reached. S33. Insert the two fixed shafts 32 of each anchor body 3 into the two fixed cylinders 4 respectively; S34. The two fixing shafts 32 of the anchor body 3 are brought close together and fixed by the fixing clamp, which is located between the collar 31 and the fixing cylinder 4 of the anchor body 3. S35. Insert the fixed shaft 32 of the anchor body 3 into the borehole and inject cement grout into the borehole.

[0058] In S33, after the fixed shaft 32 passes through the through hole of the limiting ring 41, the retaining ring 42 is installed on the shaft body of the fixed shaft 32 and connected to the connecting cylinder; in S35, after the cement grout has submerged the fixed cylinder 4, the collar 31 of the anchor body 3 is pulled into the tunnel, the fixed shaft 32 drives the limiting ring 41 to move, the limiting ring 41 pushes the retaining strip to unfold and insert into the cement grout, and then the cement grout continues to be injected until the borehole is filled.

[0059] S4 also includes the following steps: S41. The support cylinder 5 is fitted onto the collar 31 of the anchor body 3; S42, the end of the support cylinder 5 away from the slider 51 is inserted into the cement grout, and the other end is exposed in the tunnel; S43. Adjust the length of the support cylinder 5 inserted into the cement grout until the collar 31 of the anchor body 3 contacts the slider 51.

[0060] In S5, within the set period following the construction of S4, observe the position and status of the support cylinder 5 inside the tunnel: When the slider 51 inside the support cylinder 5 does not slide out, it indicates that the area where the support cylinder 5 is located is safe and qualified; When the slider 51 inside the support cylinder 5 slides out, it indicates that a rock burst has occurred in the area where the support cylinder 5 is located, and the support strength in the area where the support cylinder 5 is located needs to be increased. In S6, after the set cycle is reached, the support cylinder 5 is removed or sheared, and sprayed with sprayed concrete on the surface of the initial sprayed concrete 6. Geotextile and waterproof membrane are then installed on the surface of the sprayed concrete in sequence, and finally, secondary lining concrete is constructed on the surface of the waterproof membrane.

[0061] Specifically, the reinforcing mesh 1 has a rectangular structure with hexagonal or rhomboid meshes. The width of each reinforcing mesh 1 is less than or equal to 3m. The circumferential length of each reinforcing mesh 1 laid along the tunnel is L, where L is the arc length of the tunnel wall, with an additional 100cm length reserved for overlapping at the two arch feet of the tunnel. The reinforcing mesh 1 is a flexible composite metal mesh made of 2.7mm diameter steel wire and 8mm steel wire rope woven in a double-twisted manner. The interval between adjacent reinforcing mesh 1 is less than 20cm, and they are connected and fixed to each other by rope clamps. The reinforcing mesh 1 is fixed to the initial shotcrete 6 and the rock surface by U-shaped steel clips.

[0062] Anchor body 3 passes through reinforcing mesh 1 in a quincunx pattern. The steel wire rope used in anchor body 3 has a diameter of 16mm-20mm and a length of ≥2.5m. The fixing clamp spacing of the fixing shaft 32 on anchor body 3 is ≥8cm. Support rope 2 is 4 times the width of reinforcing mesh 1 with a 1m margin. It is fixed to the mesh surface of reinforcing mesh 1 by a tensioning device. Support rope 2 passes through collar 31 and is fixed, and abuts against reinforcing mesh 1. Tensioning components are provided on both sides of support rope 2 to limit the tension in the length direction and prevent loosening. The tensioning component is a hand-operated hoist.

[0063] In this embodiment, the support cylinder 5 is installed in the same way as in embodiment 2. The side of the support cylinder 5 away from the guide rail is inserted into the uncured cement grout, and the slider 51 abuts against the support rope 2. During subsequent dismantling, the support cylinder 5 outside the cement grout is cut off. If the internal structure is not damaged, it can continue to be used. Preferably, the material of the support cylinder 5 is easy to cut off manually.

[0064] In S5 and S6, the cycle is set to 5-7 days. During this period, according to the content of Example 2, it can be determined whether a rockburst has occurred based on whether the slider 51 has slid down, and corresponding measures can be taken to increase the support strength or remove the support cylinder 5.

[0065] For the exposed rock walls of the excavated tunnel, a wet spraying robotic arm is used to spray initial and secondary shotcrete made of steel fiber reinforced concrete onto the tunnel rock surface, allowing subsequent processes to be carried out in a safe space. The steel fiber reinforced concrete has high toughness and is not easily broken when subjected to rock burst impact. It only deforms and cracks but still maintains its integrity, which significantly improves construction safety.

[0066] The reinforcing mesh is installed using a curtain-style method. The mesh sheets are prefabricated according to the arc length and excavation depth of the tunnel. After arriving on site, they can be laid as a whole along the arch foot of the sidewall to the arch crown, significantly improving installation efficiency and reducing construction costs. Its overall stress distribution and stress dispersion effects are superior to traditional block meshes, resulting in a more robust structure and facilitating faster construction cycles. Longitudinal support ropes pass through loops, and tensioning components ensure that the reinforcing mesh and steel fiber reinforced concrete are tightly bonded to the rock surface, enhancing the support strength and durability.

[0067] In the construction of ultra-deep, high-stress tunnels prone to rockbursts, a multi-layered, high-strength protective system is constructed using steel fiber reinforced concrete, a rectangular double-twisted hexagonal reinforcing mesh, multiple double-strand steel wire ropes anchored into the structure, and multiple longitudinally arranged support ropes. This system effectively resists the ejection of flying rocks caused by strong-delayed rockbursts, maintains structural integrity, and collectively inhibits surrounding rock deformation and loosening, significantly improving construction safety and structural durability. It also reduces the need for steel arch frames, shotcrete, steel mesh, and system anchor bolts, improving construction efficiency while lowering costs. This support structure boasts advantages such as high strength, prefabrication, and convenient construction, reducing the single-cycle operation time from 17 hours to 13 hours, effectively accelerating project progress.

[0068] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A support structure for resisting tunnel rockburst, characterized by, The utility model relates to a tunnel supporting structure, including: A plurality of reinforced mesh (1); A plurality of support rope (2), the length direction both ends of support rope (2) are provided with tensioning assembly; A plurality of anchor body (3), anchor body (3) is obtained by the bending of steel wire rope along the midpoint of its own axis 180 DEG, the bending forms a set of ring (31), the both sides of set of ring (31) are fixed shaft (32), the inner wall of tunnel is provided with a plurality of drill hole, fixed shaft (32) is located in drill hole, set of ring (31) is located outside drill hole, drill hole is injected with cement slurry, a plurality of anchor body (3) equidistantly set up on reinforced mesh (1); Support cylinder (5), support cylinder (5) is detachably connected on set of ring (31), the bottom of support cylinder (5) is connected with base (55), the base (55) is used to clamp the grid of reinforced mesh (1) between support cylinder (5), Wherein, the inner wall of tunnel is sprayed with initial spraying concrete (6), adjacent reinforced mesh (1) is connected by rope clamp and is laid on the surface of initial spraying concrete (6) along the circumferential direction of tunnel, a plurality of support rope (2) equidistantly passes through set of ring (31) along the axial direction of tunnel and is in contact with reinforced mesh (1), fixed shaft (32) is connected with fixed cylinder (4), fixed cylinder (4) is used to increase the anchoring strength of fixed shaft (32), support cylinder (5) is used to improve the support strength of reinforced mesh (1), and when being impacted, is transmitted to adjacent support cylinder (5) through connecting piece.

2. A support structure for resisting tunnel rockburst according to claim 1, wherein: The inner peripheral wall of fixed cylinder (4) is provided with a sliding groove, a limiting ring (41) is slidably connected in the sliding groove, and the end of the sliding groove is connected with a clamping strip. The clamping strip can rotate outward along the sliding groove. A through hole is formed in the middle of the limiting ring (41). The fixed shaft (32) passes through the through hole and is connected with the limiting ring (41).

3. A support structure for resisting tunnel rockburst according to claim 2, wherein: The end of the sliding groove and the bottom of the fixed cylinder (4) have a spacing. The radius of the limiting ring (41) is greater than the distance from the inner wall of the clamping strip to the center of the fixed cylinder (4). The bottom of the limiting ring (41) is connected with a connecting cylinder. The cylinder cavity of the connecting cylinder is in communication with the through hole. A clamping ring (42) is detachably connected to the fixed shaft (32). The clamping ring (42) is used to connect with the connecting cylinder.

4. A support structure for resisting tunnel rockburst according to claim 1, characterized in that: The bottom surface of the support cylinder (5) is fixedly connected with a shaft rod (56). The shaft rod (56) and the inner wall of the support cylinder (5) have a spacing. The top surface of the support cylinder (5) is provided with a connecting hole (57). The shaft rod (56) is provided with a transition hole (561) in the radial direction. The inner wall of the support cylinder (5) is provided with a buckle (58) away from the connecting hole (57). The set of ring (31) is sleeved on the buckle (58) through the connecting hole (57) and the transition hole (561).

5. A support structure for resisting tunnel rockburst according to claim 4, characterised in that: The guide rail is arranged in the cylinder wall of the supporting cylinder (5), the sliding block (51) is slidably connected on the guide rail, the bottom of the shaft rod (56) is provided with an annular groove, the rotating shaft (54) is rotatably connected in the annular groove, the outer circumferential wall of the rotating shaft (54) is provided with a spiral groove (541), the inner circumferential wall of the sliding block (51) is connected with the guide rod (511), the end of the guide rod (511) is slidably connected in the groove (541), the plug hole (53) is penetrated through the sliding block (51), the supporting rope (2) is arranged in the plug hole (53) and passes through the transition hole (561) to be arranged in the supporting cylinder (5).

6. A support structure for resisting tunnel rockburst according to claim 4, wherein: The outer circumferential wall of the shaft rod (56) is connected with the breakable shaft (52), and the other end of the breakable shaft (52) is connected with the inner circumferential wall of the sliding block (51).

7. A support structure for resisting tunnel rockburst according to claim 5, wherein: The connecting piece is a flexible connecting rope (512), and every four sliding blocks (51) are sequentially connected by the connecting rope (512) along the length direction of the reinforcing mesh (1).

8. A support structure for resisting tunnel rockburst according to claim 5, wherein: The side, facing the shaft rod (56), of the base (55) is connected with a plurality of clamping pins, and the side, facing the base (55), of the rotating shaft (54) is provided with a plurality of clamping holes for clamping the clamping pins, and the end of the rotating shaft (54), close to the base (55), is always located outside the sliding block (51) when the sliding block (51) slides or is static.

9. A support structure for resisting tunnel rockburst according to claim 5, wherein: The surface of the initial spraying concrete (6) is also sprayed with re-spraying concrete, a plurality of geotextiles and waterproof plates are mounted on the surface of the re-spraying concrete, and a plurality of detachable fixing clamps are arranged on the two fixing shafts (32) of the anchor body (3) at equal intervals.

10. A method of construction for a support structure to resist tunnel rockburst, characterized by, The supporting structure according to any one of claims 1-9 is used for tunnel construction, and comprises the following steps: S1, excavating out slag, removing hazards on the rock surface, preparing a wet spraying trolley, and spraying initial spraying concrete (6) on the rock surface of the tunnel; S2, laying a reinforcing mesh (1); S3, drilling holes to install anchor bodies (3) and injecting cement slurry for fixation; S4, after repeating S1-S3 for several cycles, installing a supporting rope (2) through the thimble (31) and installing a supporting cylinder (5); S5, checking the safety state of the tunnel rock burst; S6, dismounting the supporting cylinder (5), re-spraying concrete, and sequentially mounting geotextiles and waterproof plates, and then performing secondary lining concrete construction.

11. The construction method of the supporting structure for resisting tunnel rock burst according to claim 10, wherein: in the S2, a plurality of reinforcing meshes (1) are laid along one side of the tunnel springing to the other side of the springing and closely adhere to the surface of the initial spraying concrete (6) in the S1, and the mesh surface of the reinforcing mesh (1) is fixed to the surface of the initial spraying concrete (6) by a U-shaped steel clamp, adjacent reinforcing meshes (1) are fixed to each other by a rope clamp, and each of the springings on the two sides of the tunnel is left with a length of 50 cm for reverse wrapping of the reinforcing mesh (1).

12. The construction method of the supporting structure for resisting tunnel rock burst according to claim 10, wherein: the S3 further comprises the following steps: S31, drilling holes to the surface of the initial spraying concrete (6) through the mesh holes of the reinforcing mesh (1) and cleaning the holes; S32, folding the steel wire rope along the center of the axial direction of the steel wire rope to form an anchor body (3); repeating the preparation of the anchor body (3) to the required number; S33, inserting two fixing shafts (32) of each of the anchor bodies (3) into two fixing barrels (4) respectively; S34, fixing the two fixing shafts (32) of the anchor body (3) close to each other by a fixing clamp, the fixing clamp being located between the fixing barrel (4) and the collar (31) of the anchor body (3); S35, inserting the fixing shaft (32) of the anchor body (3) into the drill hole and injecting cement slurry into the drill hole.

13. The construction method of a supporting structure for resisting rock burst of a tunnel according to claim 12, characterized in that: In the S33, after the fixing shaft (32) passes through the through hole of the limiting ring (41), the clamping ring (42) is installed on the shaft body of the fixing shaft (32) and connected with the connecting barrel; in the S35, after the cement slurry covers the fixing barrel (4), the collar (31) of the anchor body (3) is pulled into the tunnel, the fixing shaft (32) drives the limiting ring (41) to move, the limiting ring (41) pushes the clamping strip to expand and insert into the cement slurry, and then the cement slurry is continuously injected until the drill hole is filled.

14. The construction method of a supporting structure for resisting rock burst of a tunnel according to claim 10, characterized in that: The S4 further comprises the following steps: S41, sleeving the support barrel (5) at the position of the collar (31) of the anchor body (3); S42, inserting one end of the support barrel (5) away from the sliding block (51) into the cement slurry, and the other end is exposed in the tunnel; S43, adjusting the length of the support barrel (5) inserted into the cement slurry until the collar (31) of the anchor body (3) abuts against the sliding block (51).

15. The construction method of a supporting structure for resisting rock burst of a tunnel according to claim 10, characterized in that: In the S5, observing the position and state of the support barrel (5) in the tunnel within a set period after the S4 construction: When the sliding block (51) in the support barrel (5) does not slide out, it indicates that the area where the support barrel (5) is located is safe and qualified; When the sliding block (51) in the support barrel (5) slides out, it indicates that rock burst has occurred in the area where the support barrel (5) is located, and the support strength in the area where the support barrel (5) is located needs to be improved; In the S6, after the set period is reached, the support barrel (5) is removed or sheared, the secondary sprayed concrete is sprayed on the surface of the primary sprayed concrete, the geotextile and the waterproof board are installed on the surface of the secondary sprayed concrete in sequence, and finally the secondary lining concrete is constructed on the surface of the waterproof board.

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