Construction support system and method for hard rock lag-type cake layer rock burst type

Abstract

The application discloses a construction supporting system and method for hard rock lag type pie layer rock burst type, and relates to the technical field of tunnel supporting.The supporting system comprises a supporting component and an anchor protection component.The supporting component comprises a flexible steel rope layer, a primary nano material steel fiber concrete layer, a steel structure net layer and a secondary nano material fiber concrete layer arranged in sequence.The anchor protection component comprises a plurality of energy releasing anchor rods and a plurality of full-length bonded anchor rods.Taking the surface of the supporting component close to the rock layer as a reference surface, the energy releasing anchor rods and the full-length bonded anchor rods are arranged in a rectangular array, and adjacent rows and columns of the rectangular array are staggered.The supporting method is implemented by using the supporting system.The supporting system and method combine flexibility and rigidity, match the lag type pie layer rock burst characteristics, can effectively weaken the impact and influence of rock burst, and thus effectively weaken or eliminate the damage of the lag type pie layer rock burst to the rock mass.

Description

Technical Field

[0001] This invention relates to the field of tunnel support technology, and more specifically, to a construction support system and method for hard rock delayed-type cake-layer rockburst. Background Technology

[0002] Under high ground stress conditions, the excavated cross-section is well-formed with a high residual porosity. However, over time, the cross-section formation deteriorates, and the residual porosity from blasting essentially disappears. Shallow rock-like defects appear in the surrounding rock within the supported sections. These defects are thin-layered, with nearly uniform strike and orientation, and exhibit tensile fracture surfaces. The depth of these defects is mostly 0.2m–0.4m, with some areas reaching 0.5m–1m. This is a significant contributing factor to secondary damage in high ground stress zones. The delayed-type shallow rock-like defects worsen with increasing burial depth and tunnel diameter. Higher stress levels, higher rockburst intensity levels, and longer support delay times result in more severe damage from these delayed-type shallow rock-like defects.

[0003] In existing tunnel support systems and processes, the configuration of anchor bolts only considers the radial connection support function. This not only fails to buffer and release energy from rock impacts, but even if some buffering and energy release functions are considered, the support strength is still poor, resulting in unsatisfactory support effects.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] The first objective of this invention is to provide a construction support system for hard rock delayed-type cake layer rockburst. This support system, by configuring anchor components with a specific distribution of energy-releasing anchors and full-length bonded anchors on the basis of the support components, can both buffer the rock impact to a certain extent and provide sufficient support strength, thus achieving a good support effect.

[0006] The second objective of this invention is to provide a construction support method for hard rock delayed-type cake layer rockburst. This support method utilizes the aforementioned support system for installation and construction, which not only possesses the advantages of the support system but also ensures construction safety, practicality, and good process support effect during construction.

[0007] The embodiments of the present invention are implemented as follows:

[0008] Firstly, a construction support system for a hard rock delayed-type rockburst type includes a support component and an anchoring component. The support component includes a flexible steel rope layer, a primary sprayed nanomaterial steel fiber concrete layer, a steel mesh layer, and a secondary sprayed nanomaterial fiber concrete layer arranged sequentially along a first direction, wherein the first direction is the direction connecting the rock strata to the tunnel. The anchoring component includes multiple energy-releasing anchors and multiple full-length bonded anchors. One end of each energy-releasing anchor and full-length bonded anchor is inserted into the rock strata, and the other end passes through the support component. The distribution relationship of the multiple energy-releasing anchors and multiple full-length bonded anchors is as follows: taking the surface of the support component near the rock strata as the reference plane, the energy-releasing anchors and full-length bonded anchors are arranged in a rectangular array, and the adjacent rows and columns of the rectangular array are staggered.

[0009] In an optional embodiment, a pad is provided at the intersection of the energy-releasing anchor and the full-length bonded anchor with the steel mesh layer, and the pad is pressed tightly against the outside of the steel mesh layer.

[0010] In an optional embodiment, the nanomaterials in the initial sprayed nanomaterial steel fiber concrete layer and the subsequent sprayed nanomaterial fiber concrete layer are XPM nanomaterials.

[0011] In an optional embodiment, the steel reinforcement mesh layer adopts a grid structure with a grid size of 5cm × 5cm.

[0012] In an optional embodiment, the spacing between adjacent energy-releasing anchors is no more than 1.2m, and the length of the energy-releasing anchor is shorter than the length of the full-length bonded anchor.

[0013] In an optional embodiment, the energy-releasing anchor bolt includes an anchor bolt body and anchor bolt heads and pre-tightening components connected to both ends of the anchor bolt body. An energy-releasing component is installed between the anchor bolt body and the pre-tightening component, and the pre-tightening component forms a pre-tightening part for adjusting the supporting force of the energy-releasing component.

[0014] In an optional embodiment, the energy-releasing component includes a sleeve and an energy-releasing spring and a damper disposed within the sleeve. The energy-releasing spring is located on the side of the damper closer to the pre-tightening component. One end of the sleeve is connected to the anchor rod body via a connector, and the other end is movably connected to the pre-tightening component. The pre-tightening component can extend into the sleeve and act on the energy-releasing spring.

[0015] In an optional embodiment, the pre-tightening component includes a support rod, a nut, an energy release ring, and a support plate. One end of the support rod forms a pre-tightening part, and the other end is fitted with a nut. The support plate is sleeved on the support rod between the pre-tightening part and the nut. The support plate is used to support the rock wall of the rock stratum. The energy release ring is disposed between the support plate and the nut through a connecting piece.

[0016] Secondly, a construction support method for a delayed-type rockburst in hard rock is proposed, applying the aforementioned construction support system for the delayed-type rockburst in hard rock. This method includes: S1: Smooth blasting is used during tunnel excavation. After slag removal, loose rocks are cleared from the excavation face and surrounding tunnel walls, followed by high-pressure water jet washing; S2: After cleaning, the tunnel is left to stand for 2-3 days to determine if construction safety conditions are met. If they are, surface spalling is removed; S3: Flexible steel wire mesh is installed, followed by initial spraying of nano-material steel fiber concrete; S4: Energy release anchors are installed, followed by full-length bonded anchors; S5: After anchor installation, a steel mesh layer connects the energy release anchors and full-length bonded anchors. Pads are installed at the points where the energy release anchors, full-length bonded anchors, and steel mesh intersect, followed by re-spraying of nano-material fiber concrete.

[0017] In an optional implementation, in step S4, the anchor head and rod body of the energy release anchor are placed in the borehole before the energy release anchor is installed.

[0018] The beneficial effects of the embodiments of the present invention are:

[0019] The construction support system for hard rock delayed-type cake-layer rockburst provided in this embodiment of the invention utilizes a support component consisting of a flexible steel rope layer, a primary sprayed nanomaterial steel fiber concrete layer, a steel mesh layer, and a secondary sprayed nanomaterial fiber concrete layer as the basic support component. Combined with an anchoring component consisting of a specifically distributed energy-releasing anchor bolt and a full-length bonded anchor bolt, it can not only provide sufficient support for the tunnel rock strata, but also cope with a certain degree of rock strata impact, and still ensure sufficient support strength during the buffering energy release process.

[0020] The construction support method for delayed rockburst type in hard rock provided by the embodiments of the present invention uses the above-mentioned support system for installation and construction. It not only ensures the safety and reliability of tunnel support throughout the entire construction process, but also has the support advantages of the support system and can cope with reliable support scenarios for delayed rockburst type.

[0021] In general, the construction support system and method for delayed-type rockburst in hard rock provided by the embodiments of the present invention combines flexibility and rigidity, which is in line with the characteristics of delayed-type rockburst and can effectively reduce the impact and influence of rockburst, thereby effectively reducing or eliminating the harm of delayed-type rockburst to the rock mass. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A cross-sectional structural diagram of the support system provided in an embodiment of the present invention;

[0024] Figure 2 A cross-sectional structural diagram of the support component provided in an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the assembly of the anchoring component provided in an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the structure of the anchoring assembly provided in an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram showing the distribution of the anchoring components provided in an embodiment of the present invention.

[0028] Icons: 1- Flexible steel rope layer; 2- Initial sprayed nanomaterial steel fiber concrete layer; 3- Steel mesh layer; 4- Re-sprayed nanomaterial fiber concrete layer; 5- Energy release anchor; 6- Full-length bonded anchor; 7- Rock stratum; 8- Pad; 51- Pre-tightening component; 52- Energy release component; 53- Anchor rod body; 54- Anchor head; 511- Nut; 512- Connecting piece; 513- Energy release ring; 514- Support plate; 521- Energy release spring; 522- Damper; 523- Sleeve; 524- Connector. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed during use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] Furthermore, the terms "parallel" and "perpendicular" do not imply that components must be absolutely parallel or perpendicular, but rather that they can be slightly tilted. For example, "parallel" simply means that its direction is more parallel than "perpendicular," not that the structure must be perfectly parallel, but that it can be slightly tilted.

[0034] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0035] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] Example

[0037] Under high ground stress conditions, the excavated cross-section is well-formed with a high residual porosity. However, as time progresses, the cross-section formation deteriorates, and the residual porosity essentially disappears. Approximately 2-3 days after excavation, rockburst becomes prominent, resulting in V-shaped craters (0.1m-0.2m) at the arch shoulder, and spalling, splitting, and tension failure occurring on the upstream and downstream sidewalls. To address the rock mass damage caused by this delayed-type rockburst, this embodiment provides a construction support system and method for hard rock with delayed-type rockburst, which can effectively reduce or eliminate the harm of delayed-type rockburst to the rock mass and improve the quality of construction support.

[0038] Please refer to the details. Figure 1 , Figure 2and Figure 5 This embodiment provides a construction support system for a hard rock delayed-type cake-layer rockburst type, including a support component and an anchor component. The support component serves as the basic support body for the tunnel rock stratum 7, and the anchor component serves as a key component for the impact-resistant support of the rock stratum 7. Specifically, the support component includes a flexible steel rope layer 1, a primary sprayed nanomaterial steel fiber concrete layer 2, a steel mesh layer 3, and a secondary sprayed nanomaterial fiber concrete layer 4, arranged sequentially along a first direction. The first direction is the direction connecting the rock stratum 7 to the tunnel, that is, the direction from the rock stratum 7 to the center of the tunnel. The flexible steel rope layer 1, the primary sprayed nanomaterial steel fiber concrete layer 2, the steel mesh layer 3, and the secondary sprayed nanomaterial fiber concrete layer 4 are laid sequentially.

[0039] In some implementations, the tunnel is arched, meaning the overall shape of the support assembly matches the shape of the tunnel and is also arched. In this case, the first direction is the direction of the approximate diameter of the arch, so that the overall shape of the flexible steel rope layer 1, the initial sprayed nanomaterial steel fiber concrete layer 2, the steel mesh layer 3, and the re-sprayed nanomaterial fiber concrete layer 4 is also a cylindrical form with an arched cross-section.

[0040] The outermost flexible steel reinforcement layer 1 is a crucial energy-absorbing structure of the protective netting and its main load-bearing structure. It effectively intercepts projectile rocks generated by rock bursts and resists the impact of the rocks. The nanomaterials in the middle layer (initial sprayed nanomaterial steel fiber concrete layer 2) and the innermost layer (re-sprayed nanomaterial fiber concrete layer 4) are XPM nanomaterials. XPM nanomaterials are a new type of inorganic nano-level multi-effect and multi-functional admixture that integrates water reduction, reinforcement, and rapid setting. It can reduce the rebound of shotcrete, reduce dust in the tunnel, improve the early compressive strength of shotcrete, increase the thickness of a single spraying, and improve the impermeability of shotcrete. The innermost steel reinforcement mesh layer 3 uses, for example, a 5mm diameter mesh with a 5cm x 5cm grid size.

[0041] The anchoring assembly includes multiple energy-releasing anchors 5 and multiple full-length bonded anchors 6. One end of each energy-releasing anchor 5 and full-length bonded anchor 6 is inserted into the rock stratum 7, and the other end passes through the support assembly (sequentially passing through the flexible steel rope layer 1, the initial sprayed nanomaterial steel fiber concrete layer 2, the steel mesh layer 3, and the re-sprayed nanomaterial fiber concrete layer 4). The energy-releasing anchors 5 primarily serve as a buffer between the support assembly and the rock stratum 7, while the full-length bonded anchors 6 primarily serve as a stable connection between the support assembly and the rock stratum 7.

[0042] To achieve a better balance between the connection strength and buffering effect between the support component and the rock stratum 7, the distribution of the energy-releasing anchors 5 and the full-length bonded anchors 6 in the anchoring component needs to be optimized. The distribution relationship of multiple energy-releasing anchors 5 and multiple full-length bonded anchors 6 is as follows: Taking the surface of the support component near the rock stratum 7 as the reference plane, the energy-releasing anchors 5 and the full-length bonded anchors 6 are arranged in a rectangular array, and the adjacent rows and columns of this rectangular array are staggered. That is, if the surface (outer surface) of the support component near the rock stratum 7 is an arc-shaped surface, and the rectangular surface unfolded from this arc-shaped surface is taken as the reference plane, all the energy-releasing anchors 5 and all the full-length bonded anchors 6 are arranged in a rectangular array on this reference plane (e.g., Figure 5 As shown in the diagram, the rectangular array here does not specifically refer to a standard rectangular array. The adjacent rows and columns are staggered, that is, every four adjacent points are combined into a rhombus shape, so that all the energy-releasing anchors 5 and all the full-length bonded anchors 6 are arranged in a "plum blossom" pattern.

[0043] Through the above technical solutions, the anchoring component utilizes the flexible energy-releasing anchor 5 and the rigidly connected full-length bonded anchor 6 as intermediate support components, which can ensure both the buffering effect and the support strength, achieving a good balance. Furthermore, the arrangement of the energy-releasing anchor 5 and the full-length bonded anchor 6 can provide support in the latitude and longitude directions of the reference plane, ensuring the uniformity of the support and the balance of forces, thereby achieving high support quality.

[0044] In some embodiments, all energy-releasing anchors 5 and all full-length bonded anchors 6 are arranged in a rectangular array on the reference surface. The number of full-length bonded anchors 6 may be greater than the number of energy-releasing anchors 5 to ensure the strength of the support. Furthermore, the spacing between adjacent energy-releasing anchors 5 is no greater than 1.2m, and the length of each energy-releasing anchor 5 is shorter than the length of each full-length bonded anchor 6. For example, the length of each energy-releasing anchor 5 is 4m, and the length of each full-length bonded anchor 6 is 6m. This distribution pattern achieves a support effect that combines sufficient buffering (the two interact) with adequate support.

[0045] Based on the above scheme, in order to ensure the support stability of the energy-releasing anchor 5 and the full-length bonded anchor 6, a pad 8 is provided at the intersection of the energy-releasing anchor 5 and the full-length bonded anchor 6 with the steel reinforcement mesh layer 3. The pad 8 is tightly pressed against the outside of the steel reinforcement mesh layer 3 (the pad 8 presses down on the steel reinforcement mesh layer 3). By configuring the pad 8, the energy-releasing anchor 5 and the full-length bonded anchor 6 can be fixed, thereby ensuring the stability of the intermediate connection between the energy-releasing anchor 5 and the full-length bonded anchor 6.

[0046] Please see Figure 3 and Figure 4In this embodiment, the energy-releasing anchor 5 can effectively reduce the energy generated by rockburst impact through its energy-releasing component 52, and can effectively absorb the energy generated by rockburst, avoiding damage to the support structure by rockburst and preventing delayed failure of the rock mass. Specifically, the energy-releasing anchor 5 includes an anchor body 53 and anchor heads 54 (for example, using an expansion-shell type anchor head, which can effectively improve the anchoring strength and anchor performance) and a pre-tightening component 51 connected to both ends of the anchor body 53. An energy-releasing component 52 is installed between the anchor body 53 and the pre-tightening component 51. The pre-tightening component 51 forms a pre-tightening part for adjusting the supporting force of the energy-releasing component 52, thereby coping with different degrees of rockburst by adjusting the buffer support degree of the energy-releasing component 52.

[0047] More specifically, the energy-releasing component 52 includes a sleeve 523 and a (high-strength) energy-releasing spring 521 and a (high-strength) damper 522 disposed within the sleeve 523. The energy-releasing spring 521 is located on the side of the damper 522 closer to the pre-tightening component 51. One end of the sleeve 523 is fixedly connected to the anchor rod body 53 (detachable) via a connector 524, and the other end is movably connected to the pre-tightening component 51 (e.g., threaded connection, sliding connection, etc., allowing a certain axial displacement). The pre-tightening component can extend into the sleeve 523 and act on the energy-releasing spring 521.

[0048] Based on the above scheme, the pre-tightening component 51 includes a support rod, a nut 511, an energy release ring 513, and a support plate 514. One end of the support rod forms the pre-tightening part, which can slide into the sleeve 523, and the other end cooperates with the nut 511. The support plate 514 is fixedly sleeved on the support rod between the pre-tightening part and the nut 511. The support plate 514 is used to support the rock wall of the rock layer 7. The energy release ring 513 is set between the support plate 514 and the nut 511 through a connecting piece 512.

[0049] Through the above technical solutions, tightening the nut 511 can apply varying degrees of pressure to the energy release ring 513. Furthermore, the strength or material of the energy release ring 513 can be adjusted to address different levels of rockburst. When a rockburst occurs in the rock stratum 7 (rock wall) and impacts the surrounding rock and anchor bolts (energy release anchor bolts 5), the (expansion shell type) anchor head 54 provides a stronger fixing effect. The energy release spring 521 and damper 522 of the energy release component 52 can absorb a large amount of the impact force generated by the rockburst. The energy release ring 513 of the pre-tightening component 51 is the final step, absorbing the remaining small amount of impact force, ensuring that the rock mass is not affected by the delayed-type rockburst damage. This support system, targeting the characteristics of delayed-type rockburst damage, can grasp its time effect, effectively avoiding damage to on-site facilities and hazards to the personal safety of construction workers caused by delayed-type rockbursts.

[0050] This embodiment also provides a construction support method for the delayed-type rockburst in hard rock, using the aforementioned construction support system for the delayed-type rockburst in hard rock. The method includes:

[0051] S1: Smooth blasting is used during tunnel excavation. After muck removal, loose rocks are removed from the excavation face and surrounding tunnel walls, followed by high-pressure water jet washing. This step indicates the use of the drill-and-blast method (stress-relief blasting is an active means of controlling rockbursts). In areas prone to rockbursts, the method of "deep pre-splitting, short advance, and weak blasting" is adopted. During stress-relief blasting, the excavation advance should generally not exceed 2 meters, and the hole depth should be 2-2.5 times the advance. After muck removal, loose rocks are removed from the working face, and the face is promptly washed with high-pressure water jets.

[0052] S2: After cleaning, let it stand for 2-3 days to determine if the conditions for construction safety are met. If the conditions for construction safety are met, remove the surface flakes. This step indicates that for the characteristics of delayed-type rockburst, it is necessary to let it stand for 2-3 days. After standing for 2-3 days, if the conditions for construction safety are met, remove the surface flakes.

[0053] S3: Install the flexible steel reinforcement rope layer 1, and then construct the initial sprayed nanomaterial steel fiber concrete layer 2. This step involves immediately installing the flexible steel reinforcement rope netting after removing surface spalling, followed by initial spraying of 15-20cm of nanomaterial steel fiber concrete. The flexible steel reinforcement rope layer 1 is a crucial energy-absorbing structure of the protective netting and its main load-bearing structure. It effectively intercepts projectile rocks generated by rock bursts and resists the impact of rock fragments.

[0054] S4: The energy-releasing anchor bolts are installed first, followed by the installation of the full-length bonded anchor bolts. This step indicates that after the mesh spraying is completed, the anchor bolt construction is carried out immediately. First, the energy-releasing anchor bolts 5 are installed, followed by the full-length bonded anchor bolts 6. The two are distributed in the above-mentioned plum blossom pile structure.

[0055] S5: After the anchor bolt construction is completed, the energy-releasing anchor bolt 5 and the full-length bonded anchor bolt 6 are connected by the steel mesh layer 3. A pad 8 is installed at the point where the energy-releasing anchor bolt 5, the full-length bonded anchor bolt 6 and the steel mesh layer 3 pass through (the rod body of the energy-releasing anchor bolt 5 and the full-length bonded anchor bolt 6 is, for example, a 22mm threaded steel anchor bolt standard, and is fixed by the pad 8). Then, the construction of the nano-material fiber concrete layer 4 is carried out, for example, a 10-15cm nano-material steel fiber concrete layer is sprayed.

[0056] In some embodiments, in step S4, the anchor head and rod body of the energy-releasing anchor 5 are first placed in the borehole before the remaining components of the energy-releasing anchor 5 are installed. Specifically, a hole is first drilled using a water drill, and the aforementioned energy-releasing anchor 5 is used. The anchor rod body 53, which matches the inner diameter of the borehole and has an (expansion shell type) anchor head 54, is placed in the borehole. A support frame is arranged at the exposed part of the anchor rod body 53, and anchoring agent is injected using grouting equipment to fix the (expansion shell type) anchor head 54. Then, high-strength energy-releasing spring 521, high-strength damper 522, and energy-releasing ring 513 that meet the requirements are selected according to the rock mass stress parameters and the severity of rockburst. The support strength effect is proportional to the strength of the three materials. After the energy-releasing components 52 are fixed, the support plate 514, energy-releasing ring 513, connecting piece 512, and nut 511 are installed in sequence. The support plate 514 is tightly attached to the rock wall. The support plate 514, the energy release ring 513, and the connecting piece 512 are tightly connected and finally tightened and fixed by the pre-tightening nut 511.

[0057] When the surrounding rock stratum 7 is subjected to rockburst impact energy, the aforementioned flexible steel rope layer 1 and energy-releasing anchor 5 can absorb the rockburst impact energy to achieve a shock absorption effect, thereby reducing the degree of rock mass deformation. The steel mesh layer 3 and the full-length bonded anchor 6 have sufficient bearing capacity to achieve the function of support and reinforcement. The combination of flexible and rigid support can effectively reduce or even avoid the damage to the rock mass caused by delayed-type rockburst, allowing the rock mass to smoothly transition through the rockburst delay period and reach a stress-stable state.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention. It should be noted that the structures or components illustrated in the accompanying drawings are not necessarily drawn to scale, and descriptions of well-known components, processing techniques, and processes have been omitted to avoid unnecessarily limiting the invention.

Claims

1. A construction support system for hard rock delayed-type cake-layer rockburst, characterized in that, include: The support assembly includes a flexible steel rope layer, a primary sprayed nanomaterial steel fiber concrete layer, a steel mesh layer, and a secondary sprayed nanomaterial fiber concrete layer arranged sequentially along a first direction, wherein the first direction is the line direction connecting the rock strata to the tunnel. An anchoring assembly, comprising multiple energy-releasing anchors and multiple full-length bonded anchors, wherein one end of each energy-releasing anchor and each full-length bonded anchor is inserted into the rock stratum, and the other end of each passes through the support assembly; The distribution relationship of the multiple energy-releasing anchor bolts and the multiple full-length bonded anchor bolts is as follows: Using the surface of the support component near the rock stratum as the reference plane, the energy-releasing anchor and the full-length bonded anchor are arranged in a rectangular array, and the adjacent rows and columns of the rectangular array are staggered.

2. The construction support system for the delayed-type rockburst in hard rock as described in claim 1, characterized in that, A pad is provided at the intersection of the energy-releasing anchor rod and the full-length bonded anchor rod with the steel reinforcement mesh layer, and the pad is pressed tightly against the outside of the steel reinforcement mesh layer.

3. The construction support system for the delayed-type rockburst in hard rock as described in claim 1, characterized in that, The nanomaterials in the initial sprayed nanomaterial steel fiber concrete layer and the subsequent sprayed nanomaterial fiber concrete layer are XPM nanomaterials.

4. The construction support system for the delayed-type rockburst in hard rock as described in claim 1, characterized in that, The steel reinforcement mesh layer adopts a grid structure with a grid size of 5cm × 5cm.

5. The construction support system for the delayed-type rockburst in hard rock as described in claim 1, characterized in that, The spacing between adjacent energy-releasing anchors is no greater than 1.2m, and the length of each energy-releasing anchor is shorter than the length of the full-length bonded anchor.

6. The construction support system for the delayed-type rockburst in hard rock as described in any one of claims 1-5, characterized in that, The energy-releasing anchor bolt includes an anchor bolt body, an anchor bolt head, and a pre-tightening component connected to both ends of the anchor bolt body. An energy-releasing component is installed between the anchor bolt body and the pre-tightening component, and the pre-tightening component forms a pre-tightening part for adjusting the supporting force of the energy-releasing component.

7. The construction support system for the delayed-type rockburst in hard rock as described in claim 6, characterized in that, The energy-releasing component includes a sleeve and an energy-releasing spring and a damper disposed within the sleeve. The energy-releasing spring is located on the side of the damper closer to the pre-tightening component. One end of the sleeve is connected to the anchor rod body via a connector, and the other end is movably connected to the pre-tightening component. The pre-tightening component can extend into the sleeve and act on the energy-releasing spring.

8. The construction support system for the delayed-type rockburst in hard rock as described in claim 7, characterized in that, The pre-tightening component includes a support rod, a nut, an energy release ring, and a support plate. One end of the support rod forms the pre-tightening part, and the other end is fitted with the nut. The support plate is sleeved on the support rod between the pre-tightening part and the nut. The support plate is used to support the rock wall of the rock stratum. The energy release ring is disposed between the support plate and the nut through a connecting piece.

9. A construction support method for hard rock delayed-type cake layer rockburst, characterized in that, The method, employing a construction support system for hard rock delayed-type cake-layer rockburst as described in any one of claims 2-8, comprises: S1: Smooth blasting is used during tunnel excavation. After the slag is removed, dangerous rocks are removed from the excavation face and surrounding tunnel walls, and then high-pressure water jets are used for washing. S2: After cleaning, let it stand for 2-3 days to determine if the conditions for construction safety are met. If the conditions for construction safety are met, remove the surface flakes. S3: Perform the meshing operation of the flexible steel rope layer, and then carry out the construction of the initial sprayed nanomaterial steel fiber concrete layer; S4: Carry out the construction and installation of the energy-releasing anchor bolt, and then carry out the construction and installation of the full-length bonded anchor bolt; S5: After the anchor bolt construction is completed, the energy-releasing anchor bolt and the full-length bonded anchor bolt are connected by the steel mesh layer. A pad is installed at the point where the energy-releasing anchor bolt, the full-length bonded anchor bolt and the steel mesh layer pass through, and then the nanofiber concrete layer is sprayed.

10. The construction support method for the delayed-type rockburst of hard rock as described in claim 9, characterized in that, In step S4, the anchor head and rod body of the energy-releasing anchor are first placed in the borehole before the energy-releasing anchor is installed.

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