Self-repairing support system for altered surrounding rock of pumped-storage power station

Abstract

The present invention provides a self-healing support system for altered surrounding rock in a pumped storage power station, which relates to the technical field of underground structure support and includes: a fractal anchoring structure, including a main anchor rod and a number of multi-stage bifurcated anchor rods arranged along the length extension direction of the main anchor rod. A grouting main pipe is arranged inside the main anchor rod, and grouting branch pipes are arranged inside the multi-stage bifurcated anchor rods. The grouting main pipe and the grouting branch pipes are connected; a number of hydraulic gradient-responsive hierarchical repair structures are evenly distributed on the main anchor rod and the multi-stage bifurcated anchor rods; wherein, the hydraulic gradient-responsive hierarchical repair structure at least includes a first-level repair unit, and the first-level repair unit includes a first repair agent and a first pressure-triggering membrane wrapping the first repair agent. When the seepage pressure in the altered surrounding rock reaches a first threshold value, the first pressure-triggering membrane ruptures to release the first repair agent to fill the cracks. The present invention has the advantages of improving the anchoring effect, automatically repairing cracks, enhancing the stability of the surrounding rock, and adapting to different seepage pressures.

Description

Technical Field

[0001] The present invention relates to the technical field of underground structure support, and particularly to a self - repairing support system for altered surrounding rock of a pumped - storage power station. Background Art

[0002] Due to tectonic action or hydrothermal activity, altered rock has significantly deteriorated mineral composition and physical and mechanical properties, featuring low strength, developed fissures, poor integrity, water - softening and swelling when encountering water, etc. It is extremely prone to safety accidents such as large deformation of the surrounding rock of the chamber, collapse, and even seepage failure, seriously threatening the safety during the construction and operation periods of the chamber. The underground powerhouse of a pumped - storage power station is usually built in rock mass. Due to the existence of natural fissures, faults or alteration zones in the selected site area, groundwater will seep into the powerhouse through these weak zones, especially the seepage phenomenon is more significant under the action of high - pressure water head, exacerbating the danger of the altered surrounding rock. To deal with the altered surrounding rock, the commonly used measures in engineering are still ordinary bolt or cable - anchor reinforcement measures, which cannot ensure the safety of the altered surrounding rock under long - term water seepage; moreover, the existing specifications are also blank for the support design of the altered surrounding rock. Summary of the Invention

[0003] An object of the present invention is to overcome at least one of the above - mentioned deficiencies of the prior art, and provide a self - repairing support system for altered surrounding rock of a pumped - storage power station, which has the advantages of improving the anchoring effect, automatically repairing cracks, enhancing the stability of the surrounding rock, and adapting to different seepage pressures.

[0004] Additional aspects and advantages of the present invention will be partly set forth in the following description, and partly will become apparent from the description, or can be learned through the practice of the present invention.

[0005] According to one aspect of the present invention, there is provided a self - repairing support system for altered surrounding rock of a pumped - storage power station, including:

[0006] A fractal anchoring structure, including a main bolt and a plurality of multi - level bifurcated bolts arranged along the length extension direction of the main bolt. A grouting main pipe is arranged in the main bolt, and grouting branch pipes are arranged in the multi - level bifurcated bolts. The grouting main pipe and the grouting branch pipes are connected.

[0007] A plurality of hydraulic - gradient - responsive hierarchical repair structures, evenly distributed on the main bolt and the multi - level bifurcated bolts;

[0008] Wherein, the hydraulic - gradient - responsive hierarchical repair structure includes at least a first - level repair unit. The first - level repair unit includes a first repair agent and a first pressure - trigger membrane wrapping the first repair agent. When the seepage pressure in the altered surrounding rock reaches a first threshold, the first pressure - trigger membrane ruptures to release the first repair agent to fill the cracks.

[0009] In some exemplary embodiments of the present invention, based on the foregoing solution, each of the multi - level bifurcated bolts includes:

[0010] The first - level bifurcated rod is inclined and arranged on the main anchor rod, and has a first included angle with the main anchor rod.

[0011] The second - level bifurcated rod is inclined and arranged on the first - level bifurcated rod, and has a second included angle with the first - level bifurcated rod.

[0012] In some exemplary embodiments of the present invention, based on the foregoing solution, the first - level bifurcated rods are arranged at intervals along the length - extending direction of the main anchor rod, and the positions of adjacent first - level bifurcated rods are staggered at intervals of greater than or equal to 90° in the circumferential direction of the main anchor rod.

[0013] In some exemplary embodiments of the present invention, based on the foregoing solution, the main anchor rod includes a central chamber and an external chamber between the central chamber and the outer wall.

[0014] The self - healing support system for the altered surrounding rock of the pumped - storage power station further includes a drain pipe.

[0015] Wherein, the grouting main pipe is arranged in the central chamber, and the drain pipe is arranged in the external chamber for draining the water in the altered surrounding rock.

[0016] In some exemplary embodiments of the present invention, based on the foregoing solution, there are multiple drain pipes, and the multiple drain pipes are arranged in an array in the external chamber.

[0017] In some exemplary embodiments of the present invention, based on the foregoing solution, a number of grouting holes are also arranged on the main anchor rod, and the grouting holes communicate the grouting main pipe with the outside of the fractal anchoring structure, so that the grout can enter the anchor hole through the grouting holes.

[0018] In some exemplary embodiments of the present invention, based on the foregoing solution, the hydraulic - gradient - responsive hierarchical repair structure further includes a secondary repair unit located inside the first pressure - trigger membrane. The secondary repair unit includes a second repair agent and a second pressure - trigger membrane wrapping the second repair agent. When the seepage pressure in the altered surrounding rock reaches the second threshold value, the second pressure - trigger membrane ruptures to release the second repair agent to fill the cracks.

[0019] In some exemplary embodiments of the present invention, based on the foregoing solution, the first repair agent and / or the second repair agent is a silicate - nano - bentonite composite repair agent, and a nano - silica gel is formed after the first pressure - trigger membrane and / or the second pressure - trigger membrane rupture to release the repair agent.

[0020] In some exemplary embodiments of the present invention, based on the foregoing solution, a number of circles of hydraulic - gradient - responsive hierarchical repair structures are arranged on the main anchor rod, and each circle includes a plurality of the hydraulic - gradient - responsive hierarchical repair structures.

[0021] In some exemplary embodiments of the present invention, based on the foregoing solution, the volume of the altered surrounding rock self-repairing support system of the pumped storage power station that can be repaired satisfies:

[0022] It is proportional to the volume percentage of the first repair agent and / or the second repair agent in the core of the primary repair unit and / or the secondary repair unit, the volume of the core of the primary repair unit and / or the secondary repair unit, the total length of the main anchor rod, the number of arrangements of the hydraulic gradient-responsive hierarchical repair structures on a single secondary bifurcated rod, and the number of arrangements of the hydraulic gradient-responsive hierarchical repair structures in a circle along the circumferential direction of the main anchor rod, and is inversely proportional to the arrangement spacing of the primary bifurcated rods along the main anchor rod and the arrangement spacing of the hydraulic gradient-responsive hierarchical repair structures along the main anchor rod.

[0023] From the above technical solutions, it can be seen that the present invention has the following advantages and positive effects:

[0024] The present invention enhances the anchoring effect through the fractal anchoring structure, and combines the hierarchical pressure-triggered release repair agent mechanism of the hydraulic gradient-responsive hierarchical repair structure to achieve the dynamic filling of cracks and the self-repair of the surrounding rock, effectively coping with the change of seepage pressure, and having the advantages of improving the support stability, extending the service life, and adapting to complex geological conditions. Brief Description of the Drawings

[0025] By referring to the accompanying drawings and describing its exemplary embodiments in detail, the above and other features and advantages of the present invention will become more obvious.

[0026] Figure 1 It is a schematic diagram of the structure in a reduced scale of an embodiment of the altered surrounding rock self-repairing support system of the pumped storage power station of the present invention;

[0027] Figure 2 It is a schematic diagram of the structure in an enlarged scale of an embodiment of the altered surrounding rock self-repairing support system of the pumped storage power station of the present invention;

[0028] Figure 3 It is a schematic cross-sectional view of an embodiment of the altered surrounding rock self-repairing support system of the pumped storage power station of the present invention Figure 1 ;

[0029] Figure 4 It is a schematic cross-sectional view of an embodiment of the altered surrounding rock self-repairing support system of the pumped storage power station of the present invention Figure 2 ;

[0030] Figure 5 It is a schematic cross-sectional view of an embodiment of the altered surrounding rock self-repairing support system of the pumped storage power station of the present invention Figure 3 ;

[0031] Figure 6 It is a schematic cross-sectional view of an embodiment of the altered surrounding rock self-repairing support system of the pumped storage power station of the present invention Figure 4 ;

[0032] Figure 7 It is a schematic cross-section of an implementation manner of the self-healing support system for altered surrounding rocks of the pumped-storage power station of the present invention. Figure 5 ;

[0033] Figure 8 It is a schematic cross-section of an implementation manner of the self-healing support system for altered surrounding rocks of the pumped-storage power station of the present invention. Figure 6 。

[0034] Description of the reference numerals in the drawings

[0035] 1. Fractal anchoring structure; 11. Main bolt; 12. Multi-stage bifurcated bolt; 121. First-stage bifurcated rod; 122. Second-stage bifurcated rod; 123. Central chamber; 124. External chamber; 13. Grouting main pipe; 14. Grouting branch pipe; 15. Grouting hole; 2. Hydraulic gradient response type hierarchical repair structure; 211. First repair agent; 212. First pressure trigger membrane; 3. Drain pipe. Specific implementation manners

[0036] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. Like reference numerals in the figures denote the same or similar structures, and thus their detailed descriptions will be omitted.

[0037] The features, structures, or characteristics described above can be combined in any suitable manner in one or more embodiments. If possible, the features discussed in each embodiment are interchangeable. In the above description, many specific details are provided to give a thorough understanding of the embodiments of the present invention. However, those skilled in the art will realize that the technical solutions of the present invention can be practiced without one or more of the specific details, or other methods, components, materials, etc. can be adopted. In other cases, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the present invention.

[0038] Although relative terms such as "upper" and "lower" are used in the present invention to describe the relative relationship of one component of an icon to another component, these terms are used in the present invention only for convenience, for example, according to the directions of the examples described in the drawings. It can be understood that if the device of the icon is flipped so that it is upside down, the component described as "upper" will become the component described as "lower". Other relative terms such as "high", "low", "top", "bottom", "front", "rear", "left", "right", etc. also have similar meanings. When a structure is "on" another structure, it may mean that a structure is integrally formed on another structure, or that a structure is "directly" disposed on another structure, or that a structure is "indirectly" disposed on another structure through another structure.

[0039] In the present invention, the terms "a", "one", "the", "said" and "at least one" are used to indicate the existence of one or more elements / components / etc.; the terms "comprising", "including" and "having" are used to mean an open inclusion and mean that there may be additional elements / components / etc. in addition to the listed elements / components / etc. The terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0040] In the prior art, the underground powerhouse of a pumped-storage power station is often built in a rock mass containing an altered zone. Natural fissures and faults lead to an increase in groundwater seepage. Under the action of high-pressure water heads, the surrounding rock is prone to softening expansion and crack propagation. Traditional bolt support only provides passive support and cannot sense the change of seepage pressure. The repair agent cannot be accurately released to the crack propagation area, and long-term water seepage is likely to cause anchoring failure. The linear structure of conventional grouting bolts is difficult to adapt to the characteristics of multi-directional fissure development, and the slurry diffusion path is single, resulting in insufficient reinforcement in local areas.

[0041] To solve the above problems, the present invention discovers the correlation between seepage pressure and surrounding rock damage and conceives to use the pressure signal as the triggering condition for the release of the repair agent. Considering that the fissures in the altered surrounding rock present multi-scale fractal characteristics, the bifurcated structure of tree roots is used for reference to enhance the spatial adaptability of the anchoring system. By constructing a connected grouting network of the main rod and the bifurcated rods, the penetration of the slurry in the three-dimensional fissures is realized. Based on the distribution law of the seepage gradient, a hydraulic gradient response type hierarchical repair structure 2 is arranged at the key nodes of the bolt to form a hierarchical repair mechanism.

[0042] Therefore, the present invention proposes a self-repairing support system for the altered surrounding rock of a pumped-storage power station, referring to Figures 1 to 7 As shown, it includes a fractal anchoring structure (1), which includes a main bolt (11) and a plurality of multi-stage bifurcated bolts (12) arranged along the length extension direction of the main bolt (11). A grouting main pipe (13) is arranged in the main bolt (11), and a grouting branch pipe (14) is arranged in the multi-stage bifurcated bolt (12), and the grouting main pipe (13) and the grouting branch pipe (14) are connected;

[0043] A number of hydraulic gradient-responsive hierarchical repair structures 2, refer to Figure 2 as shown, are evenly distributed on the main anchor rod 11 and the multi-stage bifurcated anchor rod 12;

[0044] Among them, the hydraulic gradient-responsive hierarchical repair structure 2 at least includes a primary repair unit, and the primary repair unit includes a first repair agent 211 and a first pressure-triggering membrane 212 that wraps the first repair agent 211. When the seepage pressure in the altered surrounding rock reaches the first threshold value, the first pressure-triggering membrane 212 ruptures to release the first repair agent 211 to fill the cracks.

[0045] The fractal anchoring structure 1 refers to a three-dimensional anchoring system with a multi-stage bifurcated topology, which can be specifically realized by a tree-like branch structure. The main anchor rod 11 extends in the direction parallel to the axis of the anchor hole as the main trunk, and the multi-stage bifurcated anchor rods 12 are distributed at intervals along the axial direction of the main anchor rod 11 to form a spatial anchoring network covering multi-directional fissures. The hydraulic gradient-responsive hierarchical repair structure 2 refers to a trigger-type repair unit arranged according to the seepage pressure gradient distribution. In some embodiments, the hydraulic gradient-responsive hierarchical repair structure 2 can be realized by wrapping a repair agent with a pressure-sensitive polymer material, and its layout position matches the surrounding rock stress concentration area. The first pressure-triggering membrane 212 refers to a sealing material layer with a predetermined rupture strength, such as a composite membrane of polyvinyl alcohol and nano-clay, and the first threshold value can be set according to the permeability coefficient of the surrounding rock.

[0046] The grouting main pipe 13 and the grouting branch pipes 14 form a connected grouting channel, so that the grout can flow into each grouting branch pipe 14 along the grouting main pipe 13, and then evenly and efficiently fill the rock mass pores and cracks around the main anchor rod 11 and the multi-stage bifurcated anchor rods 12. In this way, on the one hand, the bonding force between the anchor rod and the surrounding rock can be enhanced, making the anchor rod and the surrounding rock form a tight whole, and greatly improving the reliability and stability of the anchoring. On the other hand, during the filling process of the grouting liquid, it plays a certain role in strengthening the surrounding rock, improving the mechanical properties of the surrounding rock, and reducing the risk of deformation and damage caused by the inherent defects of the surrounding rock. In addition, this connected grouting structure can also flexibly adjust the grouting pressure and the grout flow rate according to the specific conditions of the surrounding rock in different areas. For areas with complex geological conditions and different degrees of rock mass fragmentation, targeted enhanced grouting can be carried out to ensure that the fractal anchoring structure 1 can exert the best anchoring efficiency under different geological conditions.

[0047] The present invention does not make specific limitations on the material and shape of the main anchor rod 11. For example, in some embodiments, the main anchor rod 11 can also be arranged to include a central chamber 123 and an outer chamber 124 between the central chamber 123 and the outer wall;

[0048] The self-healing support system for the altered surrounding rock of the pumped-storage power station further includes a drain pipe 3;

[0049] Among them, the grouting main pipe 13 is arranged in the central chamber 123, and the drain pipe 3 is arranged in the outer chamber 124 for draining the water in the altered surrounding rock.

[0050] The central chamber 123 refers to the longitudinally penetrating channel formed inside the main bolt 11, which can be specifically realized by using a seamless steel pipe or a high-strength plastic pipe as a partition structure, and is used to accommodate the grouting main pipe 13 and ensure the sealing of slurry transportation. The outer chamber 124 refers to the annular space formed between the central chamber 123 and the outer wall of the main bolt 11, and is used to arrange the drain pipe 3 and form a seepage water drainage channel. In some embodiments, the main bolt 11 can be designed as a hollow cylindrical bolt formed by a fiber-reinforced polymer (such as a basalt fiber-reinforced polymer), and the hollow structure forms the central chamber 123 to facilitate the installation of the grouting main pipe 13. The drain pipe 3 refers to a seepage guiding device arranged in the outer chamber 124, which can be specifically realized by using a seamless steel pipe, and is used to direct the seepage water in the surrounding rock fissures.

[0051] During the implementation process, the main bolt 11 is constructed as a double-layer cavity structure: the central chamber 123 is specifically used for the arrangement of the grouting main pipe 13, and the slurry is transported to the anchoring area through the grouting main pipe 13; the outer chamber 124 is distributed around the central chamber 123, and the built-in drain pipe 3 therein forms a connection with the surrounding rock fissure network. When seepage occurs in the surrounding rock, the outer chamber 124 can quickly respond to the seepage change because it is closer to the surrounding rock fissure development area. Therefore, the drain pipe 3 can preferentially capture the seepage water and drain it to the preset drainage channel, reducing the pore water pressure inside the surrounding rock. This structural separation design enables the grouting process not to block the drainage path, and at the same time, the drainage operation does not interfere with the slurry consolidation. The two form a non-interfering collaborative working mechanism in space, effectively overcoming the technical obstacle of functional cross-interference in the traditional technology.

[0052] That is to say, the present invention can realize the directional drainage of the seepage water in the surrounding rock, avoid the softening and swelling of the rock mass caused by the accumulation of water pressure, and at the same time maintain the structural stability of the anchoring system. By physically isolating the grouting and drainage functions, it not only ensures the complete consolidation of the anchoring slurry, but also establishes a reliable seepage diversion mechanism, suppressing the occurrence of seepage failure at the root.

[0053] In some other embodiments, refer to Figure 2As shown, multiple drain pipes 3 can be designed. The multiple drain pipes 3 are arranged in an array within the outer chamber 124. That is to say, the drain pipes 3 can be arranged within the outer chamber 124 at regular intervals and in a specific direction. Specifically, an orthogonal grid or a circular radial layout can be adopted to ensure that the drainage channels evenly cover the area around the main bolt 11, forming a densely distributed seepage diversion path. When the seepage water pressure inside the surrounding rock increases, the seepage water is quickly diverted through the array of drain pipes 3 in the outer chamber 124 and discharged at the end of the bolt. The array arrangement enables each drain pipe 3 to undertake the seepage diversion task in a local area, avoiding blockage or failure of a single drainage path due to overload. At the same time, the regularly arranged drain pipes 3 form a symmetric structure in space, reducing the risk of pipe body deformation caused by uneven stress and maintaining long-term drainage stability.

[0054] In addition, it can also be designed to set a number of grouting holes 15 on the main bolt 11 (refer to Figure 8 as shown), and the grouting holes 15 communicate with the main grouting pipe 13 and the outside of the fractal anchoring structure 1, so that the grout can enter the bolt hole through the grouting holes 15.

[0055] Among them, the grouting hole 15 refers to a hole channel penetrating through the surface of the main bolt 11. Specifically, it can be processed by embedding a steel pipe in the outer chamber 124 to form a grouting channel, and it is a round hole with a diameter range of 3 - 8 mm, evenly distributed along the axial and circumferential directions of the main bolt 11. This hole channel serves as the outlet for the flow of the grout, guiding the high-pressure grout in the main grouting pipe 13 to the outer surface of the main bolt 11.

[0056] Specifically, when a cement-based or epoxy resin-based grout is injected into the main grouting pipe 13, the grout diffuses outward along the grouting holes 15 under the drive of pressure. After the grout enters the annular space between the main bolt 11 and the bolt hole wall through the grouting holes 15, it penetrates into the micro-crack network of the altered rock mass under capillary action. In addition, grouting branch pipes 14 are also arranged inside the extension structure of the multi-stage bifurcated bolt 12, which promotes the grout to flow in multiple directions along the axial and radial directions of the branch bolts, and finally forms a continuous consolidated body in three-dimensional space. This process effectively makes up for the defects of traditional bolt grouting, such as slurry accumulation at the end and incomplete filling in the middle.

[0057] The present invention does not limit the specific structure of the multi-stage bifurcated bolt 12. For example, in some embodiments, the multi-stage bifurcated bolt 12 includes at least a first-stage bifurcated rod 121 and a second-stage bifurcated rod 122. Refer to Figures 1 to 7 as shown, the first-stage bifurcated rod 121 is inclined on the main bolt 11 and forms a first angle with it, and the second-stage bifurcated rod 122 is inclined on the first-stage bifurcated rod 121 and forms a second angle with it.

[0058] Among them, the primary bifurcated rod 121 refers to a branched rod extending from the side wall of the main bolt 11, and specifically, it can form an integral structure with the main bolt 11 by using a prefabrication process. This structure expands the anchoring range through the first included angle, and the range of the first included angle can be controlled between 30° and 60° (such as 30°, 45°, 60°, etc.), so that the branched bolts can cover the fracture development areas in different directions around the main bolt 11. The secondary bifurcated rod 122 refers to a secondary anchoring unit formed by further bifurcating on the primary bifurcated rod 121, and specifically, it can be manufactured by using a prefabrication and forming process. The second included angle can be designed to be 45° to 90° (such as 45°, 60°, 90°, etc.) relative to the extension direction of the primary bifurcated rod 121, and is used to capture the secondary cracks derived from the periphery of the main crack.

[0059] In this way, after the primary bifurcated rod 121 extends from the main bolt 11 at the first included angle, the stress it bears is dispersed twice by the secondary bifurcated rod 122. When the main control crack is generated in the surrounding rock, the primary bifurcated rod 121 changes its extension path through the first included angle to form an anchoring support matching the secondary crack trend; when the secondary crack expands around the main crack, the secondary bifurcated rod 122 changes its extension path through the second included angle to form an anchoring support matching the secondary crack trend. This hierarchical bifurcated structure enables the bolt system to establish a multi-level stress transfer path and form a self-similar fractal anchoring system in the fractured rock mass. It can not only increase the contact area between the bolt and the rock mass, but also dynamically adjust the anchoring direction according to the actual crack trend, making the stress distribution more uniform. Compared with the conventional bolt that can only deal with cracks of a single scale, this structure realizes the synchronous anchoring of the main and secondary cracks through two-level bifurcation. Of course, in some embodiments, multiple secondary bifurcated rods 122 can be designed, or a tertiary bifurcated rod can be further provided on the basis of the secondary bifurcated rod 122, and the specific setting method is determined according to the actual situation, and the present invention does not make specific limitations.

[0060] In some embodiments, with reference to Figures 3 to 6 As shown, the primary bifurcated rods 121 can also be designed to be arranged at intervals in a spiral shape along the length extension direction of the main bolt 11, and the positions of adjacent primary bifurcated rods 121 are staggered at intervals of greater than or equal to 90° in the circumferential direction of the main bolt 11.

[0061] The interval setting means that the bifurcated rods are discontinuously distributed along the axis of the main bolt 11, and specifically, it can be realized by using a fixed spacing or variable spacing mode. By longitudinally discretely arranging, the continuous stress transfer along the axis direction of the main bolt 11 leading to local stress concentration is avoided. The staggered setting means that adjacent primary bifurcated rods 121 form a spatial phase difference in the circumferential direction of the main bolt 11, and specifically, it can be realized by the way of being prefabricated in one processing with the main bolt 11. By circumferentially offset distribution, a three-dimensional support network is constructed to eliminate the blind area of single-plane support.

[0062] Specifically, the axial spacing arrangement enables the first-level bifurcated rods 121 to form discrete support nodes longitudinally, interrupting the linear propagation path of the rock mass stress along the longitudinal direction of the main bolt 11 and reducing the risk of stress superposition. The circumferential staggered arrangement enables the support directions of adjacent bifurcated rods to form spatial complementarity. For example, four first-level bifurcated rods 121 are respectively located at 0°, 90°, 180°, and 270° phases in the circumferential direction, forming a three-dimensional support system with full circumferential coverage; or three first-level bifurcated rods 121 are respectively located at 0°, 120°, and 240° phases in the circumferential direction. This spatial layout not only avoids the crushing of the rock mass caused by the multi-level bifurcated bolts 12 at the same circumferential position, but also disperses the shear stress through multi-angle support points, and does not affect the setting of the drain pipe 3.

[0063] The hydraulic gradient response type hierarchical repair structure 2 is arranged at the position where the contact stress between the fractal anchoring structure 1 and the surrounding rock suddenly changes. When the seepage pressure breaks through the first threshold, it triggers the rupture of the first pressure trigger membrane 212, enabling the repair agent to penetrate along the crack. The hierarchical structure of the multi-level bifurcated bolts 12 expands the coverage range and repair volume of the repair unit, enabling the repair agent to reach the crack areas at different depths. The synergistic effect of the main bolt 11 and the multi-level bifurcated bolts 12 can optimize the stress transmission path and disperse the shear stress generated by the deformation of the surrounding rock.

[0064] In some embodiments, the hydraulic gradient response type hierarchical repair structure 2 can be designed to further include a secondary repair unit located inside the first pressure trigger membrane 212. The secondary repair unit includes a second repair agent and a second pressure trigger membrane that wraps the second repair agent. When the seepage pressure in the altered surrounding rock reaches the second threshold, the second pressure trigger membrane ruptures to release the second repair agent to fill the crack.

[0065] The secondary repair unit refers to an independent repair component nested inside the first pressure trigger membrane 212, which can be specifically implemented by a double-layer capsule structure. The inner capsule contains the second repair agent and is wrapped by the second pressure trigger membrane. This nested structure realizes the staged release control of the repair agent through physical isolation.

[0066] The second pressure trigger membrane refers to a functional material layer that responds to a specific pressure threshold, which can be specifically implemented by polymer films with different crosslinking densities. For example, when the second threshold pressure is higher than the first threshold, a polyvinyl alcohol film with a higher crosslinking degree is used. The rupture strength of this film is preset through the crosslinking degree of the molecular chains to ensure rupture under the predetermined pressure.

[0067] Specifically, when the seepage pressure of the surrounding rock reaches the first threshold, the first pressure-triggering membrane 212 on the outer layer first ruptures, releasing the first repair agent 211 to fill the initial cracks. If the seepage pressure continues to increase to the second threshold, the internal second pressure-triggering membrane will rupture immediately to release the second repair agent. The grading of the pressure thresholds is achieved through the mechanical property differences of the two triggering membranes. For example, the first threshold is set at 0.3 MPa and the second threshold is set at 0.5 MPa. The second repair agent continues to fill the expanding cracks in a higher-pressure environment to form a secondary protection. The spatial nesting relationship of the two-stage repair unit ensures that the repair agents are released in the order of the pressure gradient, avoiding release interference at different thresholds.

[0068] Through the above technical solutions, the present application realizes the multi-stage dynamic repair of the crack development of the altered surrounding rock. The first repair agent 211 treats the initial cracks at a lower pressure, and the second repair agent prevents the secondary expansion of the cracks in a higher-pressure environment, solving the technical defect that a single repair mechanism cannot adapt to the change of seepage pressure. The sequential release of the two-stage repair agents avoids the premature depletion of the repair materials, ensuring the continuous repair ability when the stress state of the surrounding rock deteriorates.

[0069] Generally, the hydraulic gradient-responsive hierarchical repair structure 2 can be evenly distributed on the surfaces of the main anchor rod 11, the first-level bifurcated rod 121, and the second-level bifurcated rod 122 of the fractal anchoring structure 1. The hydraulic gradient-responsive hierarchical repair structure 2 is evenly arranged along the circumference at the unbranched part of the main anchor rod 11, as shown in Figure 7 the figure. In some embodiments, for example, in some areas with severe alteration phenomena, it can be designed that at least several circles of the hydraulic gradient-responsive hierarchical repair structure 2 are arranged on the main anchor rod 11, and each circle includes a plurality of the hydraulic gradient-responsive hierarchical repair structure 2. In addition, in some embodiments, the adjacent hydraulic gradient-responsive hierarchical repair structures 2 can be connected to form a repair agent storage cavity.

[0070] Several circles of the hydraulic gradient-responsive hierarchical repair structure 2 are axially distributed along the main anchor rod 11, and the adjacent structures form a continuous storage space through the built-in channels. When the seepage pressure at a certain place reaches the triggering threshold, the pressure-triggering membrane of the corresponding layer ruptures to release the repair agent to fill the cracks, and at the same time, the repair agent in the storage cavity is supplemented to the ruptured area through the connecting channels. With the change of the seepage pressure gradient, different circle structures respond in turn, realizing the staged repair of the cracks from shallow to deep. The flow path of the repair agent in the storage cavity is designed to be parallel to the axis of the main anchor rod 11 to ensure the uniformity of pressure transmission and avoid the interruption of the repair agent supply caused by local pressure exceeding the limit.

[0071] At least one of the first repair agent 211 and the second repair agent adopts a composite material of silicate and nano-bentonite, and nano-silica gel can be generated after the corresponding pressure-triggering membrane ruptures.

[0072] Among them, the silicate-nano bentonite composite repair agent refers to a mixed system of a silicate substrate and nano-scale bentonite particles (with a swelling ratio of 150%-200%), and specifically, it can be achieved by mixing sodium silicate solution and modified nano-bentonite with a mass ratio of 3:1 to 5:1. Silicate (such as sodium silicate, ) undergoes a hydrolysis reaction when dissolved in water:

[0073]

[0074] The released after hydrolysis forms an alkaline environment.

[0075] The main component of bentonite is montmorillonite, which has a layered structure: alternating stacks of silicon-oxygen tetrahedron layers and aluminum-oxygen octahedron layers. Interlayer cations: such as , , etc., balance the negative charge of the structure and can be exchanged by other cations. Under the action of an alkaline environment, the interlayer cations are hydrated more strongly, the interlayer spacing expands, and at the same time, silicate ions enhance the surface negative charge, synergistically enhancing the ion exchange ability.

[0076] Nano-silica gel refers to a three-dimensional network structure formed by the sol-gel reaction of silicate catalyzed by bentonite. Specifically, the gel formation rate can be controlled by adjusting the silicate concentration and the particle size of bentonite, and the gel network can penetrate into micron-scale cracks.

[0077] Specifically, when the pressure-triggered membrane ruptures due to the seepage pressure reaching the threshold, the silicate contacts the surrounding rock seepage water with the nano-bentonite. The silicate dissolves into silicate ions under alkaline conditions, and the nano-bentonite releases calcium and magnesium ions through interlayer cation exchange, accelerating the polycondensation of silicate ions to form nano-silica gel. The gel fills the cracks through two mechanisms: on the one hand, the nano-bentonite absorbs water and swells to produce a physical plugging effect; on the other hand, the gelation process of silicate forms chemical bonds with the surrounding rock minerals to form an anti-seepage barrier. By adjusting the ratio of silicate to bentonite, the initial setting time and final strength of the gel can be controlled to adapt to the crack repair requirements under different seepage pressure environments. By enhancing the dispersibility and reaction activity of the silicate system with nano-bentonite, the repair agent has both ion exchange catalysis and nano-scale filling capabilities. Under the same seepage pressure, the gel can cover finer cracks than traditional materials, and the anti-seepage strength of the formed composite gel is improved.

[0078] The present application further proposes that the fractal anchoring structure 1 is an integrally formed part.

[0079] Among them, the fact that the fractal anchoring structure 1 is a one-piece formed part means that the main anchor rod 11 and all multi-stage bifurcated anchor rods 12 form a continuous integral structure through the same manufacturing process. Specifically, it can be achieved by metal casting or additive manufacturing techniques. For example, it can be processed from basalt fiber-reinforced polymer or directly generated by 3D printing technology to form an anchor rod assembly with fractal branches. This feature eliminates the splicing interfaces of traditional split anchor rods, enabling the fractal anchor rods to form spatial continuity in mechanical properties, thereby avoiding stress concentration or sudden changes in material properties caused by the connection parts.

[0080] Specifically, the geometric configurations of the main anchor rod 11 and the multi-stage bifurcated anchor rods 12 form a topological continuum through integrated manufacturing, and the internal grouting main pipe 13 and the grouting branch pipes 14 of the bifurcated anchor rods form a lumen connection synchronously during the manufacturing process. When the surrounding rock deforms, the external force is evenly transmitted to each level of bifurcated anchor rods through the continuous material structure of the fractal anchor rods, avoiding local stress peaks caused by material discontinuity at the traditional welding or threaded connection parts. When the anchoring system bears seepage pressure, the one-piece formed structure eliminates the corrosion penetration path at the split connection interface, preventing groundwater from invading along the connection gap and causing the anchor rods to rust.

[0081] In some specific embodiments, the main anchor rod 11 and the bifurcated anchor rods can be integrally processed using corrosion-resistant alloy materials, and the processing die designs the bifurcation angle and the number of levels according to the fractal geometric parameters. In another embodiment, the laser melting deposition technology can be used to stack layer by layer to form an anchor rod with a complex fractal structure, ensuring the continuity of the microcrystalline phase structure of each multi-stage bifurcated anchor rod 12 and the main anchor rod 11.

[0082] In addition, the volume of the altered surrounding rock self-repairing support system of the present invention that can be repaired satisfies:

[0083]

[0084] Among them, is the volume percentage of the first repair agent 211 and the second repair agent in the primary repair unit and the secondary repair unit, is the volume of the primary repair unit and the secondary repair unit; is the total length of the main anchor rod 11; is the number of arrangements of the hydraulic gradient-responsive hierarchical repair structure 2 on a single secondary bifurcated rod 122; is the arrangement spacing of the primary bifurcated rods 121 along the main anchor rod 11; is the number of arrangements of the hydraulic gradient-responsive hierarchical repair structure 2 along the circumferential direction of the main anchor rod 11 for one circle; is the arrangement spacing of the hydraulic gradient-responsive hierarchical repair structure 2 along the main anchor rod 11; m is the number of secondary bifurcated rods 122 on a single primary bifurcated rod 121.

[0085] That is to say, assuming that the altered zone forms a crack with an equivalent height of 10 cm, a length of 20 cm, and a width of 1 cm, the volume of the cavity is approximately 200 cm³. Assuming that the outermost layer of the hierarchical repair unit is a sphere with a diameter of 1 cm, the volume is 4 / 3πr³ = 0.52 cm³. The repair agents in the inner and outer layers account for 90% of the total core, which is 0.468 cm³. Among them, the outer circle accounts for 50% and the inner circle accounts for 50%, about 0.234 cm³ for each layer. Assuming that the anchor rod is 12 m long and 5 cm in diameter, and a branch is arranged every 30 cm in height, then there are 40 branches. A circle of hierarchical repair units is arranged every 15 cm in height, and there are 80 circles. There are 2 secondary bifurcated rods 122. There are 3 hierarchical repair units on one secondary bifurcated rod 122, so there are 6 hierarchical repair units on one primary bifurcated rod 121. 8 are arranged in a circle on the main anchor rod 11, with a total of 6×40 + 8×80 = 880 arranged, and a total of 880×0.468 = 411.84 cm³, of which the total volume of the outer layer repair units is approximately 205 cm³.

[0086] It should be understood that the present invention does not limit its application to the detailed structure and arrangement of the components proposed in the present invention. The present invention can have other embodiments and can be implemented and executed in various ways. The foregoing variations and modifications fall within the scope of the present invention. It should be understood that the present invention disclosed and defined herein extends to all alternative combinations of two or more separate features mentioned or apparent in the text and / or drawings. All these different combinations constitute multiple alternative aspects of the present invention. The embodiments described in the present invention illustrate the best mode known for implementing the present invention and will enable those skilled in the art to utilize the present invention.

Claims

1. A self-healing support system for altered surrounding rock in a pumped storage power station, characterized in that, Comprising: A fractal anchoring structure, including a main anchor rod and a number of multi-stage bifurcated anchor rods arranged along the length extension direction of the main anchor rod. A grouting main pipe is arranged inside the main anchor rod, and grouting branch pipes are arranged inside the multi-stage bifurcated anchor rods. The grouting main pipe and the grouting branch pipes are communicated. A number of hydraulic gradient response type hierarchical repair structures, evenly distributed on the main anchor rod and the multi-stage bifurcated anchor rods. Wherein, the hydraulic gradient response type hierarchical repair structure at least includes a first-level repair unit. The first-level repair unit includes a first repair agent and a first pressure trigger film wrapping the first repair agent. When the seepage pressure in the altered surrounding rock reaches the first threshold, the first pressure trigger film ruptures to release the first repair agent to fill the cracks.

2. The self-healing support system for altered surrounding rock of a pumped storage power station according to claim 1, wherein Each of the multi-stage bifurcated anchor rods at least includes: A first-level bifurcated rod, inclinedly arranged on the main anchor rod, having a first included angle with the main anchor rod. A second-level bifurcated rod, inclinedly arranged on the first-level bifurcated rod, having a second included angle with the first-level bifurcated rod.

3. The self-healing support system for altered surrounding rock of a pumped storage power station according to claim 2, characterized in that, The first-level bifurcated rods are arranged at intervals along the length extension direction of the main anchor rod, and the positions of adjacent first-level bifurcated rods are staggered at intervals of greater than or equal to 90° in the circumferential direction of the main anchor rod.

4. The self-healing support system for altered surrounding rock of a pumped storage power station according to claim 1, characterized in that The main anchor rod includes a central chamber and an external chamber between the central chamber and the outer wall. The self-repairing support system for the altered surrounding rock of the pumped storage power station further includes a drain pipe. Wherein, the grouting main pipe is arranged in the central chamber, and the drain pipe is arranged in the external chamber for draining the water in the altered surrounding rock.

5. The self-healing support system for altered surrounding rock of a pumped storage power station according to claim 4, characterized in that, There are multiple drain pipes, and the multiple drain pipes are arranged in an array in the external chamber.

6. The self-healing support system for altered surrounding rock of a pumped storage power station according to claim 4, characterized in that, A number of grouting holes are also arranged on the main anchor rod. The grouting holes communicate the grouting main pipe with the outside of the fractal anchoring structure, so that the slurry can enter the anchor rod hole through the grouting holes.

7. The self-repairing support system for altered surrounding rock of a pumped storage power station according to claim 1, wherein The hydraulic gradient response type hierarchical repair structure further includes a second-level repair unit located inside the first pressure trigger film. The second-level repair unit includes a second repair agent and a second pressure trigger film wrapping the second repair agent. When the seepage pressure in the altered surrounding rock reaches the second threshold, the second pressure trigger film ruptures to release the second repair agent to fill the cracks.

8. The self-healing support system for altered surrounding rock of a pumped-storage power station according to claim 7, characterized in that, The first repair agent and / or the second repair agent is a silicate-nano bentonite composite repair agent. After the first pressure trigger film and / or the second pressure trigger film rupture to release the repair agent, a nano-silica gel is formed.

9. The self-healing support system for altered surrounding rock of a pumped storage power station according to claim 1, wherein A number of circles of hydraulic gradient response type hierarchical repair structures are arranged on the main anchor rod, and each circle includes a number of the hydraulic gradient response type hierarchical repair structures.

10. The self-healing support system for altered surrounding rock of a pumped storage power station according to any one of claims 1-9, characterized in that, The volume of the altered zone that the self-repairing support system for the altered surrounding rock of the pumped storage power station can repair satisfies: It is directly proportional to the volume percentage of the first repair agent and / or the second repair agent in the core of the first-level repair unit and / or the second-level repair unit, the volume of the core of the first-level repair unit and / or the second-level repair unit, the total length of the main anchor rod, the number of arrangements of the hydraulic gradient response type hierarchical repair structures on a single second-level bifurcated rod, and the number of arrangements of the hydraulic gradient response type hierarchical repair structures in a circle along the circumferential direction of the main anchor rod, and is inversely proportional to the arrangement spacing of the first-level bifurcated rods along the main anchor rod and the arrangement spacing of the hydraulic gradient response type hierarchical repair structures along the main anchor rod.

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