Slope protection structure and construction method

Abstract

The application discloses a slope protection structure, which comprises a concrete layer, a plurality of grouting anchor cables, a rigid mesh layer and a net rack structure. The concrete layer is formed on a slope surface of a slope body. The plurality of grouting anchor cables are arranged in a matrix mode on the slope body, and the anchoring sections of the grouting anchor cables are embedded in the slope body, and the free ends of the grouting anchor cables extend out of the concrete layer. The rigid mesh layer is a rigid mesh structure covering the whole slope body surface. The net rack structure comprises anchoring nodes corresponding to the grouting anchor cables one by one, and the free ends of the grouting anchor cables are anchored on the anchoring nodes. Any anchoring node is connected with a plurality of main rod members in a radial direction of the slope body, and the other ends of the main rod members are connected with the rigid mesh layer and are embedded in the concrete layer. The connecting points of the main rod members and the rigid mesh layer are distributed in a matrix mode. The application further discloses a slope protection structure construction method. The anchor cable tension is dispersed into surface constraint through four-level force transmission of the anchoring node-main rod member-rigid mesh layer-concrete layer, the stress concentration problem is solved, and the construction efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of slope protection. More specifically, this invention relates to a slope protection structure and construction method. Background Technology

[0002] In the field of slope protection engineering, anchoring technology combined with concrete slope protection layers is a widely used core method. Traditional anchor-sprayed support structures form a basic reinforcement system by installing anchor rods or cables within the slope and supplementing them with a steel mesh and sprayed concrete surface layer. However, this type of structure has significant limitations. The core problem is that the prestress or working load applied by the anchor is mainly applied directly to a relatively small point area on the concrete surface layer through the anchor at its end. This point-concentrated stress mode is prone to stress concentration phenomena below and around the anchor. Under the action of the slope's own weight, groundwater pressure, or external loads, the stress concentration point is very likely to induce local cracking, breakage, or even spalling of the concrete surface layer. Once the surface layer fails locally, it not only weakens its function of preventing slope weathering and rainwater erosion, but also accelerates the attenuation of anchoring force, which may eventually lead to the overall failure of the slope.

[0003] To overcome the drawbacks of stress concentration in traditional anchor-sprayed structures, engineering practice has developed composite support methods such as lattice beams, frame beams, or steel beams combined with anchor cables. This transforms point-based stress into linear constraint. By setting up a grid frame composed of staggered reinforced concrete or steel beams on the slope, and placing the anchor points at the nodes of the frame, the tensile force applied by a single anchor cable is first transmitted to the nodes of the frame, and then partially distributed to adjacent nodes and the beam itself through the linear structure of the beams. Compared to pure anchor-sprayed structures, this alleviates local stress peaks to a certain extent and improves the overall structural integrity. However, this improved solution still has shortcomings. First, the frame beam structure is essentially still a discrete linear constraint; the force transmission mainly occurs along the beam's direction. The "grid" area between beams is relatively weak, making it difficult to form a true "surface" constraint. Second, the frame nodes themselves still bear the convergence of concentrated forces from beams in multiple directions, making them high-stress areas in the structure prone to failure. Therefore, although lattice and frame structures improve protection capabilities, their stress dispersion effect is still not ideal, making it difficult to achieve a high degree of uniformity of slope stress. Under complex geological or steep slope conditions, their reliability and economy face challenges.

[0004] In response to the bottlenecks in existing slope protection technologies regarding stress dispersion uniformity and structural integrity, there is an urgent need for a new type of slope protection structure. This structure should be able to efficiently and uniformly diffuse the concentrated tensile force generated by the anchors to the entire slope surface, forming a strong surface constraint effect, thereby eliminating stress concentration points to the greatest extent and improving the overall stability and durability of the slope. At the same time, the structure should also take into account the ease of construction, economy, and adaptability to complex slope surfaces. Summary of the Invention

[0005] One objective of this invention is to provide a slope protection structure and construction method that can evenly distribute the tension generated by the grouting anchor cable to the entire slope surface, forming a surface constraint effect on the slope, eliminating stress concentration points, improving the overall stability and durability of the slope, and the structure is easy to construct and cost-controllable.

[0006] To achieve these and other advantages according to the invention, in a first aspect, the invention provides a slope protection structure comprising: a concrete layer formed on the slope surface; a plurality of grouting anchors arranged in a matrix on the slope, the front ends of the grouting anchors being embedded in the slope and the free ends of the grouting anchors extending outward from the concrete layer; a rigid mesh layer, the rigid mesh layer being a rigid mesh structure covering the entire slope surface; and a grid structure comprising anchoring nodes corresponding one-to-one with the grouting anchors, the free ends of the grouting anchors being anchored to the anchoring nodes, each anchoring node being radially connected to a plurality of main members in the slope direction, the other ends of the plurality of main members being connected to the rigid mesh layer and embedded in the concrete layer, the connection points between the main members and the rigid mesh layer being distributed in a matrix; wherein the tension force generated by a single grouting anchor is uniformly applied to the slope surface through the anchoring nodes, main members, rigid mesh layer, and concrete layer in sequence.

[0007] Preferably, a number of grouting anchors are arranged at equal intervals in a quincunx pattern, and several hexagonal area units of the same size are divided around each grouting anchor. The rigid mesh layer in each area unit is composed of three prefabricated meshes. The prefabricated mesh is a parallelogram with an obtuse angle. The prefabricated mesh includes two inner mesh plates and two outer mesh plates. The prefabricated meshes in the same area unit are detachably connected to each other through the inner mesh plates. The prefabricated meshes in adjacent area units are detachably connected through the outer mesh plates. The junction of the two inner mesh plates is provided with a concave arc plate. The grouting anchor passes through the circular area formed by the splicing of the arc plates of the three prefabricated meshes.

[0008] Preferably, the precast mesh further includes an inner support frame, which includes several parallel steel pipes. One end of each steel pipe is fixed to an inner plate of the mesh, and the other end is fixed to an outer plate of the mesh. Corrugated steel bars are provided between adjacent steel pipes.

[0009] Preferably, the outer mesh panel is C-shaped, wherein the two long sides of the outer mesh panel are bent vertically towards the center of the corresponding area unit to form flanges. The flanges have screw holes. A connector is provided in the middle of two connected outer mesh panels. The connector includes a fixing plate and two symmetrically arranged fixing sleeves. The fixing plate is bolted to the corresponding two flanges. The fixing sleeves are inclined towards the anchoring nodes of the corresponding side area unit. The anchoring nodes include six connecting supports arranged around the perimeter. The surface of the connecting supports opposite to the fixing sleeves has threaded through holes. One end of the main rod is inserted into the fixing sleeve, and the other end is bolted to the corresponding connecting support.

[0010] Preferably, one end of a secondary member is detachably connected to the middle of the main member, and a secondary member support is fitted onto the other end of the secondary member, with the secondary member support fixed to the inner support frame.

[0011] Preferably, the secondary member support and connector are both embedded inside the concrete layer.

[0012] Preferably, the anchoring node includes an outer node cylinder and an inner node cylinder. The outer node cylinder is a hexagonal cylinder with a connecting support on each of its outer surfaces. The inner node cylinder is a frustum-shaped cylinder with its smaller base facing the slope. The outer wall of the inner node cylinder is connected to the inner wall of the outer node cylinder by a connecting plate. A steel strand fixing seat is matched and accommodated inside the inner node cylinder. The steel strand fixing seat has several through holes, and each through hole corresponds to a steel strand of the grouting anchor cable.

[0013] Preferably, a fixed cylinder is fixed on the slope, the grouting anchor cable passes through the fixed cylinder, the fixed cylinder extends outward from the slope, the inner cylinder of the node extends into an extension cylinder in the direction of the slope, the extension cylinder is coaxial with the fixed cylinder and has the same outer diameter, the two ends of the protective cylinder are respectively matched and sleeved on the outside of the extension cylinder and the fixed cylinder, and the protective cylinder is provided with an exhaust port and a grouting port.

[0014] Secondly, the present invention provides a construction method for a slope protection structure, applied to the aforementioned slope protection structure, comprising the following steps: S1. Drill holes into the slope body in a plum blossom pattern with equal intervals, insert the grouting anchor cables one by one into the holes and complete the grouting of the anchoring section in the holes. S2. Install a rigid mesh layer on the slope surface; S3. Complete the entire space frame structure and ensure that the steel strand of each grouting anchor cable is threaded into the corresponding anchoring node; S4. Spray concrete onto the slope surface, and the resulting concrete layer completely covers the rigid mesh layer. S5. Apply prestress to the steel strands of the grouting anchor cable one by one, using the anchoring nodes as supports. S6. Perform secondary grouting into the borehole to seal the free section inside the borehole.

[0015] Preferably, in step S1, after the grouting of the anchoring section inside the borehole is completed, a row of grouting pipes is driven into the anchoring section from top to bottom on both sides of each anchoring section, and pressure grouting is performed on the grouting pipes. The stone body formed by the pressure grouting covers the anchoring section.

[0016] The present invention has at least the following beneficial effects: First, this invention forms a four-level force transmission path through "anchoring node - main member - rigid mesh layer - concrete layer", which evenly diffuses the concentrated tension force generated by a single grouting anchor cable to the entire slope surface, forming a collaborative and continuous "surface" constraint structure system. This ensures that the tension of the grouting anchor cable is dispersed over a large area and evenly applied to the slope surface, significantly reducing the local stress peak of the concrete layer. It avoids the common problems of concrete crushing and spalling under the anchor in traditional structures and the resulting local slope instability, thus improving the integrity and durability of the protection system. Secondly, the rigid mesh layer used in this invention adopts a modular design. By dividing the rigid mesh layer into hexagonal area units centered on grouting anchor cables arranged in a quincunx pattern, and assembling them using prefabricated mesh panels, standardized and factory-produced production is achieved. The detachable connection design of the inner and outer mesh panels significantly shortens the installation cycle of the slope support structure. Anchoring nodes, connectors, main members, secondary members, and other components are connected by detachable methods such as bolts. While ensuring the reliability of force transmission at the nodes, it makes the installation and positioning of the grid structure more convenient, reduces the difficulty of on-site operations and the dependence on manual skills, and ensures the uniformity and controllability of construction quality. It is especially suitable for complex slope projects with large topographic relief or large area.

[0017] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure in one technical solution of the present invention; Figure 2 This is a schematic diagram of the internal structure of a regional unit in one technical solution of the present invention; Figure 3 This is a schematic diagram of the structural disassembly within a regional unit in one technical solution of the present invention; Figure 4 This is a schematic diagram of the region unit division in one technical solution of the present invention; Figure 5 This is a schematic diagram of a rigid mesh layer within a single region unit in one technical solution of the present invention; Figure 6 This is a schematic diagram of a prefabricated mesh in one technical solution of the present invention; Figure 7 This is a schematic diagram of the installation of prefabricated mesh panels within a single area unit in one technical solution of the present invention; Figure 8 This is a schematic diagram of the installation of prefabricated mesh between adjacent area units in one technical solution of the present invention; Figure 9 This is a schematic diagram of the inner support frame in one technical solution of the present invention; Figure 10 This is a schematic diagram of the connector installation in one technical solution of the present invention; Figure 11 This is a schematic diagram of the installation of the main member and secondary member in one technical solution of the present invention; Figure 12 This is a schematic diagram of an anchoring node in one technical solution of the present invention; Figure 13 This is a schematic diagram of the installation process of the space frame structure in one technical solution of the present invention; Figure 14 This is a schematic diagram of the sealing cylinder installation in one technical solution of the present invention; Figure 15 This is a schematic diagram of the grouting process in one technical solution of the present invention.

[0019] Attached reference numerals: 1-Slope, 2-Grouting anchor cable, 201-Anchorage section, 202-Free section, 21-Anchorage enlargement structure, 22-Support sleeve, 23-Steel strand, 3-Concrete layer, 4-Grid structure, 41-Connector, 411-Fixing plate, 412-Fixing sleeve, 42-Main member, 43-Secondary member, 431-Secondary member support, 44-Transverse member, 5-Precast mesh, 50-Arc plate, 51-Inner plate of mesh, 52-Outer plate of mesh, 53-Inner support frame, 531-Steel pipe, 532-Wave-shaped steel bar, 6-Anchorage node, 61-Outer cylinder of node, 62-Inner cylinder of node, 63-Connecting support, 621-Extension cylinder, 64-Steel strand fixing seat, 641-Through hole, 7-Fixing cylinder, 8-Casing, 81-Exhaust port, 82-Grouting port. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can implement it based on the description.

[0021] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0022] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are conventional methods, and the reagents and materials mentioned are commercially available. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "setting" should be interpreted broadly. For example, they can refer to fixed connection or setting, detachable connection or setting, or integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description. They 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, and therefore should not be construed as a limitation of this invention.

[0023] like Figures 1-15 As shown, the present invention provides a slope protection structure, comprising: a concrete layer 3; a plurality of grouting anchor cables 2 arranged in a matrix on a slope 1, the front part of each grouting anchor cable 2 being embedded inside the slope 1, and the free end of each grouting anchor cable 2 extending outward from the concrete layer 3; a rigid mesh layer, which is a rigid mesh structure covering the entire surface of the slope 1; and a grid structure 4, which includes anchoring nodes 6 corresponding one-to-one with each grouting anchor cable 2, the free end of each grouting anchor cable 2 being anchored to the anchoring node 6, and a plurality of main members 42 radially connected to each anchoring node 6 in the direction of the slope 1, the other end of each main member 42 being connected to the rigid mesh layer and embedded in the concrete layer 3, the connection points of the main members 42 and the rigid mesh layer being distributed in a matrix; wherein, the tension force generated by a single grouting anchor cable 2 is uniformly applied to the surface of the slope 1 through the anchoring node 6, the main members 42, the rigid mesh layer, and the concrete layer 3 in sequence.

[0024] In this technical solution, the grouting anchor cable 2 consists of steel strands 23 and grouting pipes. An anchoring expansion structure 21, composed of reinforcing bars and a frame, can be added to its end extending into the slope 1. During drilling, the end of the hole is enlarged. The anchoring expansion structure 21 is an existing structure that can be unfolded after drilling to form an enlarged reinforcing cage. After the grouting anchor cable 2 is inserted into the slope 1, the anchoring expansion structure 21 is opened. The grouting anchor cable 2 also includes several sections of support sleeves 22 that are fitted over the steel strands 22 to prevent hole collapse. After the grouting anchor cable 2 is placed and the anchoring expansion structure 21 is opened, grout is injected into the hole through the grouting pipe. The anchoring expansion structure 21 of the grouting anchor cable 2 and a portion of the steel strand 23 are embedded in the bottom of the hole to form the anchoring section 201. The steel strand 23 can be tensioned and locked after the grout in the anchoring section 201 reaches the required strength. The concrete layer 3 is a thin layer of cast-in-place reinforced concrete covering the surface of the slope 1, which can be formed by spraying concrete. The anchoring node 6 is a welded or cast metal bearing plate or a spherical node that can anchor the steel strand 23, fixing the outside of the slope 1. The rigid mesh layer can be spliced ​​from plates or rods into a mesh structure and fixed by auxiliary soil nails or expansion bolts inserted into the surface of the slope 1.

[0025] In this technical solution, the concrete layer 3, the rigid mesh layer, all anchoring nodes 6, and all main members 42 can be regarded as an inverted grid roof on the slope 1. Its force transmission path is considered as an inverted grid roof. Since the steel strands 23 are anchored to the anchoring nodes 6, a force is applied to the anchoring nodes 6 in the direction of the slope 1. The anchoring nodes 6 disperse the concentrated force of the anchoring nodes 6 into the rigid mesh layer through the main members 42. Since the rigid mesh layer is embedded in the concrete layer 3 and has rigidity and bending resistance, the multi-point force after dispersion is evenly applied to the surface of the slope 1 through the rigid mesh layer and the concrete layer 3. Compared with traditional anchor support, this structure greatly improves the stress diffusion efficiency and effectively suppresses local cracking.

[0026] In another technical solution, several grouting anchors 2 are arranged at equal intervals in a quincunx pattern. Each grouting anchor 2 is used as the center to divide the area into several hexagonal regions of the same size. Within each region, the rigid mesh layer is composed of three prefabricated mesh sheets 5. Each prefabricated mesh sheet 5 is a parallelogram with an obtuse angle. Each prefabricated mesh sheet 5 includes two inner mesh plates 51 and two outer mesh plates 52. The prefabricated mesh sheets 5 within the same region are detachably connected to each other via the inner mesh plates 51. In adjacent regions, the prefabricated mesh sheets 5 are detachably connected via the outer mesh plates 51. A concave arc-shaped plate 50 is provided at the junction of the two inner mesh plates 51. The grouting anchors 2 pass through the circular area formed by the splicing of the arc-shaped plates 50 of the three prefabricated mesh sheets 5. In this technical solution, the grouting anchors 2 are arranged in a quincunx pattern with equal intervals and staggered rows, which precisely protects the slope around the grouting anchor 2. 1. Divide into several equal hexagonal area units. The prefabricated mesh 5 is a parallelogram with an obtuse angle of 120° and an acute angle of 60°. Three prefabricated mesh 5 can be completely assembled into an equilateral hexagon. Therefore, three prefabricated mesh 5 can completely cover an area unit with a grouting anchor cable 2 as the center. The inner plate 51 and outer plate 52 of the prefabricated mesh 5 are strip-shaped plates with screw holes. The inner plates 51 of the three prefabricated mesh 5 are attached to each other in pairs and connected by bolts. The outer plates 52 are attached to each other in pairs with the outer plates 51 of the adjacent area unit and connected by bolts. The prefabricated mesh 5 can also be equipped with mesh reinforcement and other structures to fill the internal area of ​​the parallelogram. An arc plate 50 is set at the intersection of the adjacent inner plates 51. The three arc plates 50 can enclose a circular area for the passage of the grouting anchor cable 2.

[0027] In another technical solution, the precast mesh 5 further includes an inner support frame 53, which comprises several parallel steel pipes 531. One end of each steel pipe 531 is fixed to an inner plate 51 of the mesh, and the other end is fixed to an opposite outer plate 52 of the mesh. Corrugated reinforcing bars 532 are arranged between adjacent steel pipes 531. In this technical solution, the precast mesh 5 is manufactured by a steel structure factory. The steel pipes 531 are arranged in double rows in a staggered pattern. Both ends of the steel pipes 531 are welded between the outer plate 52 and the inner plate 51 of the mesh. The corrugated reinforcing bars 532 are welded between adjacent rows of steel pipes 531. After the concrete layer 3 is constructed, the double rows of staggered steel pipes 531... The concrete layer 3 has a dense three-dimensional skeleton, which greatly enhances the integrity and bending stiffness of the concrete layer 3. The welding of the corrugated steel bars 532 between adjacent steel pipes 531 not only plays a role in stabilizing the connection, but also effectively restricts the plastic shrinkage and micro-crack propagation of the concrete, significantly improving the crack resistance of the concrete layer 3. The three-dimensional network formed by the steel pipes 531 and the corrugated steel bars 532 evenly disperses the tensile stress borne by the concrete layer 3, and synergistically improves its overall tensile strength. This built-in steel skeleton system transforms the concrete layer 3 from a traditional brittle surface layer into a composite structural layer with excellent crack resistance and tensile strength. While uniformly applying surface load to the slope 1, it greatly extends the service life of the slope protection structure.

[0028] In another technical solution, the outer mesh plate 52 is C-shaped, wherein the two long sides of the outer mesh plate 52 are bent vertically towards the center of the corresponding area unit to form flange plates 521. Screw holes are provided on the flange plates 521. A connector 41 is provided in the middle of two connected outer mesh plates 52. The connector 41 includes a fixing plate 411 and two symmetrically arranged fixing sleeves 412. The fixing plate 411 is bolted to the corresponding two flange plates 521. The fixing sleeves 412 are inclined towards the anchoring nodes 6 of the corresponding side area unit. The anchoring nodes 6 include six connecting supports 63 arranged around the perimeter. Threaded through holes are provided on the surface of the connecting supports 63 opposite to the fixing sleeves 412. One end of the main rod 42 is fitted with a connecting support. The fixed sleeve 412 is located inside the fixed sleeve 412, and the other end is bolted to the corresponding connecting support 63. In this technical solution, the outer plate 52 of the mesh adopts a C-shaped cross-section design. Its two long sides are bent vertically towards the center of the area unit to form a flange plate 521. The flange plate 521 has a pre-made standard screw hole. The fixing plate 411 of the connector 41 is placed across the flange plates 521 of the two outer plates 52 of the mesh. The fastening connection with the two outer plates 52 is achieved by high-strength bolts passing through the screw holes of the flange plates 521. The inclined end of the fixed sleeve 412 is precisely aligned with the direction of the anchoring node 6 of the corresponding side area unit. When the main rod 42 is installed, one end is inserted into the fixed sleeve 412 to achieve axial positioning, and the other end is rigidly connected to the corresponding connecting support 63 on the anchoring node 6 by bolts.

[0029] In this technical solution, the C-shaped mesh outer plate 52, together with the vertical flange plate 521, forms a strong bending section, which significantly improves the rigidity of the plate. The connector 41 is quickly and adjustablely connected to the flange plate 521 by bolts. The symmetrically arranged fixed sleeves 412 can accurately guide the force transmission direction of the main member 42, ensuring that the tension is transmitted to the anchoring node 6 along the design angle. The two ends of the main member 42 are respectively connected to the fixed sleeve 412 by plug-in and to the connecting support 63 by bolts, forming a dual force transmission mechanism of "plug-in + bolt". This not only ensures the convenience of installation, but also provides a reliable rigid connection node, which greatly improves the installation accuracy and efficiency. At the same time, it ensures that the main member 42 distributes the concentrated load of the grouting anchor cable 2 on the anchoring node 6 in the direction of the slope 1 in the rigid mesh layer and the concrete layer 3.

[0030] In another technical solution, one end of a secondary member 43 is detachably connected to the middle of the main member 42, and the other end of the secondary member 43 is fitted with a secondary member support 431. The secondary member support 431 is fixed to the inner support frame 53. In this technical solution, the main member 42 and the secondary member 43 together form a spatial force transmission network. During construction, a connection interface is first preset in the middle of the main member 42. The connection interface refers to the existing steel structure node form, such as a connecting plate or sleeve with bolt holes. One end of the secondary member 43 is detachably connected to the connection interface via bolts or pins, while the other end is inserted into the secondary member support 431. The secondary member support 431 is initially fixed to the steel pipe 531 or corrugated steel bar 532 of the inner support frame 53 by binding wire or temporary bolts, forming a temporary positioning during the construction phase. At this time, the secondary member 43 is in a hinged state at both ends. When the concrete layer 3 is constructed, the shotcrete completely covers the secondary member support 431, the inner support frame 53, and the end of the secondary member 43. After the concrete cures, the secondary member support 431 is embedded in the concrete, transforming into a rigid fixed end. The end of the secondary member 43 is bonded to the concrete to form an integral whole, and the temporary connection between the secondary member support 431 and the inner support frame 53 is replaced by the concrete into a permanent rigid connection.

[0031] In this technical solution, the force on the secondary member 43 is transmitted to the inner support frame 53 through the secondary member support 431, and then evenly distributed to the concrete layer 3 through the steel pipe 531 and the corrugated steel bar 532, further realizing the transformation of concentrated force into multi-point force on the rigid grid layer. In addition, the connection point of the secondary member 43 in the middle of the main member 42 forms an additional support point, effectively shortening the compression free length of the main member 42 and avoiding instability of the main member 42 when transmitting force. Optionally, a transverse member 44 can be added between the connection node of the secondary member 43 and the main member 42 to further improve the overall stress stability.

[0032] In another technical solution, the secondary rod support 431 and the connector 41 are both embedded inside the concrete layer 3.

[0033] In another technical solution, the anchoring node 6 includes an outer cylinder 61 and an inner cylinder 62. The outer cylinder 61 is a hexagonal cylinder with a connecting support 63 on each of its outer surfaces. The inner cylinder 62 is a frustoconical cylinder with its smaller bottom facing the slope 1. The outer wall of the inner cylinder 62 is connected to the inner wall of the outer cylinder 61 by a connecting plate. A steel strand fixing seat 64 is fitted inside the inner cylinder 62. The steel strand fixing seat 64 has several through holes 641, which correspond one-to-one with the steel strands 23 of the grouting anchor cable 2. In this technical solution, the anchoring node 6 adopts a double-layer cylinder composite structure. The inner conical surface of the inner cylinder 62 matches the outer conical surface of the steel strand fixing seat 64. The inner cylinder 62 concentrates the dispersed tension of the steel strands 23 into axial pressure, which is evenly transmitted to the hexagonal outer cylinder 61 through the connecting plate, thus avoiding stress concentration.

[0034] In another technical solution, a fixed cylinder 7 is fixed on the slope 1, and the grouting anchor cable 23 passes through the fixed cylinder 7. A portion of the fixed cylinder 7 extends outside the slope 1. The inner cylinder 62 of the node extends into an extension cylinder 621 towards the slope 1. The extension cylinder 621 is coaxial with the fixed cylinder 2 and has the same outer diameter. A protective sleeve 8 is fitted onto the extension cylinder 621 and the fixed cylinder 2 at both ends. The protective sleeve 8 is provided with an exhaust port 81 and a grouting port 82. In this technical solution, the fixed cylinder 7 is embedded after drilling is completed on the slope 1, and the grouting anchor cable 2 passes through it. The inner cylinder 621 of the node extends into the slope 1. 2. An extension tube 621 with the same diameter as the fixed tube 7 extends out. When the protective tube 8 is installed, the two ends are respectively sleeved with the extension tube 621 and the exposed section of the fixed tube 7 to form a continuous sealed channel. The exhaust port 81 and the grouting port 82 on the protective tube 8 are kept unobstructed. The grouting pipe of the grouting anchor cable 2 extends out from the grouting port 82. When the concrete layer 3 is sprayed, the protective tube 8 ensures that the sprayed concrete does not contaminate the steel strand 23 and that the concrete does not flow into the borehole. After the steel strand 23 is tensioned, secondary grouting is performed using the grouting port 82 so that the free section 202 of the grouting anchor cable 2 is completely covered by the grouting material.

[0035] In another technical solution, a slope protection structure construction method is applied to the aforementioned slope protection structure, characterized by comprising the following steps: S1. Drill holes into the slope 1 in a staggered, quincunx pattern. Insert the grouting anchor cables 2 one by one into the holes and complete the grouting of the anchoring section 201 inside the holes. Specifically, locate the drilling points on the slope 1 in a staggered, quincunx pattern. Enlarge the end of the hole formed by the drilling rig. Install a fixing cylinder 7 at the hole opening. Insert the grouting anchor cables 2 through the fixing cylinder 7 into the hole. The grouting anchor cables 2 include an anchoring enlargement structure 21, steel strands 23, grouting pipes, and several sections of support sleeves 22. After the grouting anchor cables 2 are installed, open the anchoring enlargement structure 21 to form a mesh frame in the enlarged area at the bottom of the hole. Inject cement grout into the anchoring section 201 at the bottom of the hole through the grouting pipe so that the front section of the grouting anchor cables 2 is embedded inside the slope 1.

[0036] S2. Install a rigid mesh layer on the surface of slope 1. Specifically, after the prefabricated mesh 5 is processed in the steel structure processing plant, it is transported to the construction site and assembled in hexagonal area units with each grouting anchor cable 2 as the center. The inner plate 51 of the mesh is connected to the inner plate 51 of the adjacent mesh by bolts, and the outer plate 52 of the mesh is fixed with bolts. During assembly, ensure that the arc plates 50 of the three prefabricated mesh 5 form a circular anchor cable channel. During the installation of the rigid mesh layer, soil nails or expansion bolts can be added to the slope 1 for temporary fixation of the prefabricated mesh 5.

[0037] S3. Complete the entire grid structure and ensure that the steel strands of each grouting anchor cable 2 are threaded into the corresponding anchoring node 6. Specifically, the connector 41 is bolted onto the outer plate 52 of the grid through the fixing plate 411, the secondary member support 431 is temporarily fixed to the surface of the inner support frame 53, one end of the main member 42 is inserted into the fixing sleeve 412 of the connector 41, and the other end is bolted to the connecting support 63 of the anchoring node 6. The two ends of the secondary member 43 are respectively connected to the middle of the main member 42 and the secondary member support 431.

[0038] S4. Concrete is sprayed onto the surface of slope 1, and the resulting concrete layer 3 completely covers the rigid mesh layer. Specifically, geotextile or other roll materials are first used to cover the anchoring nodes 63 to prevent contamination. Casings 8 are installed to prevent the sprayed concrete from contaminating the exposed steel strands 23 and to prevent the sprayed concrete from flowing into the borehole. A wet spraying machine is used to spray concrete in layers, completely wrapping the rigid mesh layer, connectors 41, and secondary member supports 431 to form a continuous concrete layer 3. During spraying, the process is advanced from the slope toe to the slope top. The resulting concrete layer 3 combines with the rigid mesh layer to form a composite tensile body. The corrugated steel bars 532 suppress concrete shrinkage cracks. The inner mesh plate 51, outer mesh plate 52, and steel pipe 531 enhance the overall rigidity. The secondary member supports 431 are solidified by the concrete and become fixed ends.

[0039] S5. Apply prestress to the steel strands 23 of the grouting anchor cable 2 one by one with the anchoring node 6 as the support. With the anchoring node 6 as the reaction support, use jacks to tension the steel strands 23. The tensioning sequence follows the principle of "first the middle and then the periphery, and proceed symmetrically". The main member 42 and the secondary member 43 are compressed and transfer the force to the rigid mesh layer and the concrete layer 3 to jointly apply surface pressure to the surface of the slope 1.

[0040] S6. Perform secondary grouting into the borehole to seal the free section 202 inside the borehole. Inject micro-expansion grout into the free section 202 through the grouting port 82 of the casing 8. Exhaust air and excess water are discharged through the vent port 81. The grouting pressure is 0.3-0.5MPa until full. After the grout hardens, a full-length bonded anchor cable is formed.

[0041] In another technical solution, in step S1, after the grouting of the anchoring section 201 in the borehole is completed, a row of grouting pipes is driven from top to bottom on both sides of each row of anchoring sections 201. Pressure grouting is performed on the grouting pipes, and the stone body formed by the pressure grouting covers the anchoring section 201. In this technical solution, the construction of the grouting pipes is carried out after the initial setting of the anchoring section 201. The formed stone body eliminates the weak contact zone between the anchoring section 201 and the stratum, transforming the point anchoring into a columnar composite anchor body, and improving the ultimate pull-out resistance of the grouting anchor cable 2. For example, the grouting pipe hole position is located 0.5m off to both sides of the center line of each row of anchoring sections 201. The hole is formed vertically on the slope using an impact drill, and a seamless steel pipe with a cone head and circumferential grout outlet is quickly inserted as the grouting pipe. The bottom end of the grouting pipe extends below the bottom of the lowest anchoring section 201, and the pipe opening is connected to the grouting equipment. Ultrafine cement-based grout is injected under high pressure of 0.8-1.2 MPa, with the grouting flow rate controlled at 15-20 L / min. Grouting is terminated when grout returns from adjacent holes or when there is local bulging on the slope. The grout diffuses and permeates along the rock and soil fissures, and hardens to form a continuous and dense stone body after 24 hours.

[0042] It should be noted that although the steps are described in a specific order above, this does not mean that they must be performed in that order. In fact, some of these steps can be executed concurrently, or even in a different order, as long as the required functionality is achieved. The number of devices and processing scale described herein are for simplification of the invention; applications, modifications, and variations of this invention will be readily apparent to those skilled in the art.

[0043] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A slope protection structure, characterized in that, include: The concrete layer is formed on the slope surface of the slope. A number of grouting anchors are arranged in a matrix on the slope, with the front part of the grouting anchors embedded inside the slope and the free end of the grouting anchors extending outward from the concrete layer. Rigid mesh layer, wherein the rigid mesh layer is a rigid mesh structure covering the entire slope surface; The space frame structure includes anchoring nodes corresponding to grouting anchors. The free ends of the grouting anchors are anchored to the anchoring nodes. Each anchoring node is radially connected to several main members in the direction of the slope. The other ends of the main members are connected to the rigid mesh layer and embedded in the concrete layer. The connection points between the main members and the rigid mesh layer are distributed in a matrix. Among them, the tension generated by a single grouting anchor cable is applied evenly to the slope surface through the anchoring node, main member, rigid mesh layer and concrete layer in sequence; Several grouting anchors are arranged at equal intervals in a quincunx pattern. Each grouting anchor is used as the center to divide several hexagonal area units of the same size. The rigid mesh layer in each area unit is composed of three prefabricated meshes. The prefabricated mesh is a parallelogram with an obtuse angle. The prefabricated mesh includes two inner mesh plates and two outer mesh plates. The prefabricated meshes in the same area unit are detachably connected to each other through the inner mesh plates. The prefabricated meshes in adjacent area units are detachably connected through the outer mesh plates. The junction of the two inner mesh plates is provided with an inwardly concave arc plate. The grouting anchor passes through the circular area formed by the splicing of the arc plates of the three prefabricated meshes. The precast mesh also includes an inner support frame, which includes several parallel steel pipes. One end of each steel pipe is fixed to an inner plate of the mesh, and the other end is fixed to an outer plate of the mesh. Corrugated steel bars are provided between adjacent steel pipes. The outer mesh panel is C-shaped, with two long sides of the outer mesh panel bent vertically towards the center of the corresponding area unit to form flanges. Screw holes are provided on the flanges. A connector is provided in the middle of two connected outer mesh panels. The connector includes a fixing plate and two symmetrically arranged fixing sleeves. The fixing plate is bolted to the corresponding two flanges. The fixing sleeves are inclined towards the anchoring nodes of the corresponding side area unit. The anchoring nodes include six connecting supports arranged around the perimeter. Threaded through holes are provided on the surface of the connecting supports opposite to the fixing sleeves. One end of the main rod is inserted into the fixing sleeve, and the other end is bolted to the corresponding connecting support.

2. The slope protection structure as described in claim 1, characterized in that, One end of a secondary member is detachably connected to the middle of the main member, and a secondary member support is fitted onto the other end of the secondary member. The secondary member support is fixed to the inner support frame.

3. The slope protection structure as described in claim 2, characterized in that, The secondary member supports and connectors are all embedded inside the concrete layer.

4. The slope protection structure as described in claim 1, characterized in that, The anchoring node includes an outer cylinder and an inner cylinder. The outer cylinder is a hexagonal cylinder with a connecting support on each of its outer surfaces. The inner cylinder is a frustum-shaped cylinder with its smaller base facing the slope. The outer wall of the inner cylinder is connected to the inner wall of the outer cylinder by a connecting plate. A steel strand fixing seat is fitted inside the inner cylinder. The steel strand fixing seat has several through holes, and each through hole corresponds to a steel strand of the grouting anchor cable.

5. The slope protection structure as described in claim 4, characterized in that, A fixed cylinder is fixed on the slope, the grouting anchor cable passes through the fixed cylinder, and part of the fixed cylinder extends out of the slope. The inner cylinder of the node extends into an extension cylinder in the direction of the slope. The extension cylinder is coaxial with the fixed cylinder and has the same outer diameter. The two ends of the protective cylinder are respectively matched and sleeved on the outside of the extension cylinder and the fixed cylinder. The protective cylinder is provided with an exhaust port and a grouting port.

6. A construction method for a slope protection structure, applied to the slope protection structure described in claim 5, characterized in that, Includes the following steps: S1. Drill holes into the slope body in a plum blossom pattern with equal intervals, insert the grouting anchor cables one by one into the holes and complete the grouting of the anchoring section in the holes. S2. Install a rigid mesh layer on the slope surface; S3. Complete the entire space frame structure and ensure that the steel strand of each grouting anchor cable is threaded into the corresponding anchoring node; S4. Spray concrete onto the slope surface, and the resulting concrete layer completely covers the rigid mesh layer. S5. Apply prestress to the steel strands of the grouting anchor cable one by one, using the anchoring nodes as supports. S6. Perform secondary grouting into the borehole to seal the free section inside the borehole.

7. The slope protection structure construction method as described in claim 6, characterized in that, In step S1, after the grouting of the anchoring section inside the borehole is completed, a row of grouting pipes is driven into the two sides of each anchoring section from top to bottom, and pressure grouting is performed on the grouting pipes. The stone body formed by the pressure grouting covers the anchoring section.

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