Slope protection structure and construction method

Abstract

The invention discloses a slope protection structure which comprises a concrete layer formed on the slope surface of a slope body and a plurality of grouting anchor cables arranged on the slope body in a matrix mode, anchoring sections of the grouting anchor cables are fixedly 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 of a rigid mesh structure covering the whole surface of the slope body; the grid structure comprises anchoring nodes in one-to-one correspondence with the grouting anchor cables, the free ends of the grouting anchor cables are anchored on the anchoring nodes, any anchoring node is radially connected with a plurality of main rod pieces in the slope body direction, and the other ends of the main rod pieces are connected with the rigid mesh layer and embedded in the concrete layer; the invention further discloses a slope protection structure construction method, through four-stage force transmission of the anchoring joints, the main rod pieces, the rigid mesh layers and the concrete layers, the tensile force of the anchor cables is dispersed into surface constraint, the problem of stress concentration is solved, and efficient cooperation of construction is synchronously achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of slope protection. More particularly, the present application relates to a slope protection structure and a construction method. BACKGROUND

[0002] In the field of slope protection engineering, anchoring technology combined with a concrete slope surface protection layer is a widely used core means. A traditional anchor-shotcrete support structure forms a basic reinforcement system by setting anchor rods or anchor cables in the slope body and supplementing a steel mesh shotcrete surface layer. However, this type of structure has significant limitations. The core problem is that the prestress or working load applied by the anchoring member is mainly directly applied to a relatively small point area on the concrete surface layer through the anchor device at the end of the anchoring member. This point-type concentrated stress mode is prone to stress concentration phenomena below and around the anchor device. Under the action of its own gravity, groundwater pressure or external load, the stress concentration point is prone to induce local cracking, fragmentation or even peeling of the concrete surface layer. Once the surface layer fails locally, not only does it weaken its role in preventing weathering and rainwater erosion of the slope surface, but it also accelerates the decay of the anchoring force, which may eventually lead to overall failure of the slope body.

[0003] In order to overcome the drawbacks of stress concentration in traditional anchor-shotcrete structures, composite support forms such as lattice beams, frame beams or steel beams combined with anchor cables have been developed in engineering practice to convert point-type stress into line-type constraint. By setting a grid framework of interlaced reinforced concrete beams or steel beams on the slope surface and setting the end anchoring points of the anchor cables on the nodes of the framework, the tensile force applied by a single anchor cable is first transmitted to the nodes of the framework and then partially dispersed to adjacent nodes and the beam body itself through the linear structure of the beam. Compared to a pure anchor-shotcrete structure, this improves the overall stability of the structure to some extent, but this improved scheme still has shortcomings. First, the framework beam structure is still essentially a discrete linear constraint, and force transmission mainly occurs along the direction of the beam. The "grid" area between beams is relatively weak in terms of stress, making it difficult to form a true "surface" constraint. Second, the framework nodes themselves are still subjected to the convergence of concentrated forces from multiple directions, which are high stress areas in the structure and are prone to failure. Therefore, although lattice and frame structures improve the protection capacity, the effect of dispersing stress is still not ideal, and it is difficult to achieve high uniformity of slope stress. Under complex geological or high and steep slope conditions, the reliability and economy of the structure face challenges.

[0004] In the face of the bottlenecks of existing slope protection technologies in terms of stress dispersion uniformity and structural integrity, there is an urgent need for a new type of slope protection structure that can efficiently and uniformly diffuse the concentrated tensile force generated by the anchoring member to the entire slope surface, forming a strong surface constraint effect, thereby maximizing the elimination of stress concentration points and improving the overall stability and durability of the slope body. At the same time, the structure also needs to take into account the convenience of construction, economy and adaptability to complex slopes. Summary of the Invention

[0005] One object of the present invention is to provide a slope protection structure and construction method, which can evenly spread the tension generated by the grouting anchor cable to the entire slope surface, form a surface constraint effect on the slope, eliminate stress concentration points, and improve the overall stability and durability of the slope. The structure is easy to construct and the cost is controllable.

[0006] In order to achieve these objects and other advantages according to the present invention, in a first aspect, the present invention provides a slope protection structure, comprising: a concrete layer, which is formed on the slope surface of the slope; a plurality of grouting anchor cables, which are arranged in a matrix on the slope, the front parts of the grouting anchor cables are embedded in the interior of the slope, and the free ends of the grouting anchor cables extend outward from the concrete layer; a rigid mesh layer, which is a rigid mesh structure covering the entire surface of the slope; a grid structure, which includes anchor nodes corresponding to the grouting anchor cables one by one, the free ends of the grouting anchor cables are anchored to the anchor nodes, and any anchor node is radially connected to a plurality of main rods in the direction of the slope, the other ends of the plurality of main rods are connected to the rigid mesh layer and buried in the concrete layer, and the connection points between the main rods and the rigid mesh layer are distributed in a matrix; wherein the tensioning force generated by the single grouting anchor cable is uniformly applied to the slope surface through the anchor nodes, the main rods, the rigid mesh layer, and the concrete layer in sequence.

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

[0008] Preferably, the prefabricated mesh also includes an inner support frame, which includes a plurality of parallel steel pipes, one end of which is fixed to an inner plate of the mesh, and the other end is fixed to an opposite outer plate of the mesh, and corrugated steel bars are arranged between the majority of adjacent steel pipes.

[0009] Preferably, the outer plate body of the mesh is C-shaped, wherein the two long sides of the outer plate body of the mesh are vertically bent to one side of the center of the corresponding area unit with flange plates, screw holes are formed on the flange plates, a connecting piece is arranged at the middle part of the two connected outer plate bodies of the mesh, the connecting piece comprises a fixing plate and two symmetrically arranged fixing sleeves, the fixing plate is bolted to the corresponding two flange plates, the fixing sleeves are respectively inclined towards the anchoring nodes of the corresponding side area unit, the anchoring node comprises six connecting supports arranged around the circumference, threaded holes are formed on the surface of the connecting supports opposite to the fixing sleeves, one end of the main rod is matched and inserted into the fixing sleeve, and the other end is bolted with the corresponding connecting support.

[0010] Preferably, the middle part of the main rod is detachably connected with one end of a secondary rod, the other end of the secondary rod is sleeved with a secondary rod support, and the secondary rod support is fixed to the inner support frame body.

[0011] Preferably, the secondary rod support and the connecting piece are both embedded in the concrete layer.

[0012] Preferably, the anchoring node comprises a node outer cylinder and a node inner cylinder, the node outer cylinder is a hexagonal cylinder, one connecting support is arranged on each outer surface of the node outer cylinder, the node inner cylinder is a frustum-shaped cylinder, the small bottom of the node inner cylinder faces the slope body, the outer wall of the node inner cylinder is connected with the inner wall of the node outer cylinder through a patch, a steel strand fixing seat is matched and accommodated in the node inner cylinder, a plurality of through holes are formed in the steel strand fixing seat, and the through holes correspond one-to-one to the steel strands of the grouting anchor cables.

[0013] Preferably, a fixing cylinder is fixed on the slope body, the grouting anchor cable passes through the fixing cylinder, the fixing cylinder partially protrudes outside the slope body, the node inner cylinder extends out of the slope body to form an extension cylinder, the extension cylinder is coaxial with the fixing cylinder and has the same outer diameter, a protective cylinder is matched and sleeved outside the extension cylinder and the fixing cylinder at two ends respectively, and the protective cylinder is provided with an exhaust port and a grouting port.

[0014] In a second aspect, the application provides a slope protection structure construction method applied to the above-mentioned slope protection structure, comprising the following steps: S1, drilling holes into the slope body at equal intervals in a plum blossom shape, and sequentially inserting the grouting anchor cables into the holes and completing grouting of the anchoring sections in the holes; S2, installing a rigid mesh layer on the surface of the slope body; S3, completing the entire mesh structure and ensuring that the steel strands of each grouting anchor cable are arranged in the corresponding anchoring nodes; S4, spraying concrete on the surface of the slope body, and forming a concrete layer that completely covers the rigid mesh layer; S5, sequentially applying prestress to the steel strands of the grouting anchor cables with the anchoring nodes as supports. S6, secondary grouting is performed in the borehole to close the free section in the borehole.

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

[0016] The present application at least includes the following beneficial effects: Firstly, the present application forms a four-stage force transmission path through the "anchoring node-main rod member-rigid mesh layer-concrete layer", and the concentrated tension force generated by a single grouting anchor cable is evenly spread to the entire slope surface, forming a cooperative and continuous "surface" constraint structure system, which ensures that the tension force of the grouting anchor cable is dispersed over a large area and uniformly applied to the slope surface, significantly reduces the local stress peak of the concrete layer, avoids the common problems of concrete crushing and peeling under the anchorage device in traditional structures, and thus avoids the local damage and stability loss of the slope surface, and improves the integrity and durability of the protection system. Secondly, the rigid mesh layer used in the present application adopts modular design, and is divided into hexagonal area units centered on the grouting anchor cables arranged in a plum blossom shape, and is assembled using prefabricated mesh, which realizes standardized and factory production. The detachable connection design of the inner plate body and the outer plate body of the mesh greatly shortens the installation period of the slope support structure. The anchoring node, connecting piece, main rod member, secondary rod member and other components are connected by bolts and other detachable methods, which not only ensures the reliability of node force transmission, but also makes the installation and positioning of the mesh structure more convenient, reduces the difficulty of on-site operation and the dependence on manual skills, ensures the uniformity and controllability of construction quality, and is especially suitable for complex slope engineering with large terrain fluctuations or wide area.

[0017] Other advantages, objects and features of the present application will be apparent from the following description, and will be understood by those skilled in the art through study and practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural overall schematic diagram of one technical solution of the present application; Figure 2 is a structural schematic diagram of a region unit in one technical solution of the present application; Figure 3 is a structural exploded view of a region unit in one technical solution of the present application; Figure 4 is a region unit division schematic diagram in one technical solution of the present application; Figure 5 is a rigid mesh layer schematic diagram in a single region unit in one technical solution of the present application; Figure 6 Preform net piece schematic diagram in one technical solution of the present application; Figure 7 Preform net piece installation schematic diagram in one single area unit in one technical solution of the present application; Figure 8 Preform net piece installation schematic diagram between adjacent area units in one technical solution of the present application; Figure 9 Inner support frame body schematic diagram in one technical solution of the present application; Figure 10 Connecting piece installation schematic diagram in one technical solution of the present application; Figure 11 Main rod piece and secondary rod piece installation schematic diagram in one technical solution of the present application; Figure 12 Anchor node schematic diagram in one technical solution of the present application; Figure 13 Net rack structure installation process schematic diagram in one technical solution of the present application; Figure 14 Sealing cylinder installation schematic diagram in one technical solution of the present application; Figure 15 Grouting process schematic diagram in one technical solution of the present application.

[0019] Reference signs: 1-slope body, 2-grouting anchor cable, 201-anchoring section, 202-free section, 21-anchoring expansion structure, 22-supporting sleeve, 23-steel strand, 3-concrete layer, 4-net rack structure, 41-connecting piece, 411-fixing plate, 412-fixing sleeve, 42-main rod piece, 43-secondary rod piece, 431-secondary rod piece support, 44-transverse rod piece, 5-preform net piece, 50-arc-shaped plate, 51-net piece inner plate body, 52-net piece outer plate body, 53-inner support frame body, 531-steel pipe, 532-wavy reinforcement, 6-anchoring node, 61-node outer cylinder, 62-node inner cylinder, 63-connecting support, 621-extended cylinder, 64-steel strand fixing seat, 641-through hole, 7-fixing cylinder, 8-protecting cylinder, 81-exhaust port, 82-grouting port. DETAILED DESCRIPTION

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

[0021] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0022] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "set" should be understood in a broad sense, for example, they can be fixedly connected or set, or detachably connected or set, or integrally connected or set. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The orientations or positional relationships indicated by the terms "transverse", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present 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, which are arranged in a matrix on the slope 1, the front parts of the grouting anchor cables 2 being embedded in the interior of the slope 1, and the free ends of the grouting anchor cables 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; a grid structure 4, which comprises anchor nodes 6 corresponding to the grouting anchor cables 2 one by one, the free ends of the grouting anchor cables 2 being anchored on the anchor nodes 6, and any anchor node 6 being radially connected to a plurality of main rods 42 in the direction of the slope 1, the other ends of the plurality of main rods 42 being connected to the rigid mesh layer and buried in the concrete layer 3, and the connection points between the main rods 42 and the rigid mesh layer being distributed in a matrix; wherein the tensioning force generated by the single grouting anchor cable 2 is uniformly applied to the surface of the slope 1 through the anchor nodes 6, the main rods 42, the rigid mesh layer, and the concrete layer 3 in sequence.

[0024] In the technical solution, the grouting anchor cable 2 is composed of steel strands 23 and grouting pipes, and the end portion of the grouting anchor cable 2 extending into the slope body 1 can be additionally provided with an anchoring expansion structure 21 composed of steel bars and a frame body, the anchoring expansion structure 21 is expanded to form an expanded steel cage body after drilling, and the anchoring expansion structure 21 is opened after the grouting anchor cable 2 extends into the slope body 1, the grouting anchor cable 2 further includes a plurality of support sleeves 22 sleeved outside the steel strands 22 for preventing hole collapse, after the grouting anchor cable 2 is placed and the anchoring expansion structure 21 is opened, the hole is grouted through the grouting pipes, so that the anchoring expansion structure 21 and part of the steel strands 23 of the grouting anchor cable 2 are embedded in the hole bottom to form an anchoring section 201, and the steel strands 23 can be tensioned and locked after the grout of the anchoring section 201 reaches the strength, the concrete layer 3 is a cast-in-place reinforced concrete thin layer covering the surface of the slope body 1, which can be formed by spraying concrete, the anchoring node 6 is a welded or cast metal pressure-bearing plate body or a spherical node capable of anchoring the steel strands 23, and the anchoring node 6 is fixed outside the slope body 1, the rigid mesh layer can be formed by splicing plate bodies or rod bodies into a net structure, and is fixed by auxiliary soil nails or expansion bolts inserted into the surface of the slope body 1.

[0025] In the technical solution, the concrete layer 3, the rigid mesh layer, all the anchoring nodes 6 and all the main rod members 42 can be regarded as a net rack type roof inverted on the slope body 1, and the force transmission path is inverted as the net rack type roof, the steel strands 23 are anchored on the anchoring nodes 6, the anchoring nodes 6 exert a force on the slope body 1 in the direction of the slope body 1, the anchoring nodes 6 disperse the concentrated force of the anchoring nodes 6 to the rigid mesh layer through the main rod members 42, and the multi-point force after dispersion is uniformly applied to the surface of the slope body 1 through the rigid mesh layer and the concrete layer 3, compared with the traditional anchor rod support, the stress diffusion efficiency of the structure is greatly improved, and local cracking is effectively inhibited.

[0026] In another technical solution, a plurality of grouting anchor cables 2 are arranged at equal intervals in a quincunx shape, and a plurality of equal hexagonal area units of the same size are divided with each grouting anchor cable 2 as the center. The rigid mesh layer in each area unit is made of three prefabricated meshes 5. The prefabricated mesh 5 is a parallelogram with an inward recess at an obtuse angle. The prefabricated mesh 5 includes two mesh inner plate bodies 51 and two mesh outer plate bodies 52. The prefabricated meshes 5 in the same area unit are detachably connected to each other through the mesh inner plate bodies 51. The prefabricated meshes 5 in adjacent area units are detachably connected through the mesh outer plate bodies 51. The joint of the two mesh inner plate bodies 51 is provided with an arc-shaped plate 50 with an inward recess. The arc-shaped plates 50 of the three prefabricated meshes 5 are spliced to form a circular area through the grouting anchor cable 2. In this technical solution, the grouting anchor cables 2 are arranged at equal intervals and staggered in a quincunx shape. The grouting anchor cables 2 can divide the slope body 1 into a plurality of equal hexagonal area units with the same area. The prefabricated mesh 5 is a parallelogram with an obtuse angle of 120° and an acute angle of 60°. The three prefabricated meshes 5 can completely match an equilateral hexagon. Therefore, the three prefabricated meshes 5 can completely cover an area unit with the grouting anchor cable 2 as the center. The mesh inner plate body 51 and the mesh outer plate body 52 of the prefabricated mesh 5 are both strip-shaped plate bodies with screw holes. The mesh inner plate bodies 51 of the three prefabricated meshes 5 are attached to each other and connected by bolts. The mesh outer plate body 52 is attached to the mesh outer plate body 51 in the adjacent area unit and connected by bolts. The prefabricated mesh 5 can also be internally provided with a mesh rib and other structures to fill the internal area of the parallelogram. The arc-shaped plate 50 is arranged at the joint of the adjacent mesh inner plate bodies 51. The three arc-shaped plates 50 can enclose a circular area for the grouting anchor cable 2.

[0027] In another technical solution, the prefabricated mesh 5 further comprises an inner support frame 53, which comprises a plurality of parallel steel pipes 531, one end of the steel pipes 531 being fixed to the mesh inner plate body 51 and the other end being fixed to the opposite mesh outer plate body 52, and a plurality of corrugated steel bars 532 being arranged between adjacent steel pipes 531. In this technical solution, the prefabricated mesh 5 is processed and produced by a steel structure factory, the steel pipes 531 are arranged in double rows in a staggered manner, the two ends of the steel pipes 531 are welded between the mesh outer plate body 52 and the mesh inner plate body 51, and the corrugated steel bars 532 are welded between adjacent steel pipes 531 of different rows. After the construction of the concrete layer 3 is completed, the double-row staggered steel pipes 531 form a dense three-dimensional framework inside the concrete layer 3, greatly enhancing 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 stable connection, but also effectively limits the plastic shrinkage and micro-crack expansion 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 uniformly disperses the tensile stress borne by the concrete layer 3, and cooperatively improves the overall tensile capacity. This built-in steel framework system changes the traditional brittle surface layer of the concrete layer 3 into a composite structure layer with excellent crack resistance and tensile properties, can uniformly apply surface load to the slope 1, and greatly prolongs the service life of the slope protection structure.

[0028] In another technical solution, the mesh outer plate body 52 is in a C shape, wherein the two long edges of the mesh outer plate body 52 are vertically bent to one side of the center of the corresponding regional unit to form flange plates 521, screw holes are formed in the flange plates 521, a connecting piece 41 is arranged in the middle of the two connected mesh outer plate bodies 52, the connecting piece 41 comprises a fixed plate 411 and two symmetrically arranged fixed sleeves 412, the fixed plate 411 is bolted to the corresponding two flange plates 521, the fixed sleeves 412 are respectively inclined towards the anchoring nodes 6 of the corresponding side regional units, the anchoring nodes 6 comprise six connecting supports 63 arranged in a circle, screw through holes are formed in the surface of the connecting supports 63 opposite to the fixed sleeves 412, one end of the main rod piece 42 is matched and inserted into the fixed sleeve 412, and the other end is bolted with the corresponding connecting support 63. In this technical solution, the mesh outer plate body 52 adopts a C-shaped cross-section design, the two long edges thereof are vertically bent to form flange plates 521 at the center of the corresponding regional unit, standard screw holes are preformed in the flange plates 521, the fixed plate 411 of the connecting piece 41 is arranged on the flange plates 521 of the two mesh outer plate bodies 52, and fastening connection with the two mesh outer plate bodies 52 is realized by high-strength bolts penetrating the screw holes of the flange plates 521, the inclined end of the fixed sleeve 412 is accurately aligned in the direction of the anchoring nodes 6 of the corresponding side regional units, and when the main rod piece 42 is installed, one end thereof is inserted into the fixed sleeve 412 to realize axial positioning, and the other end is rigidly connected with the corresponding connecting support 63 of the anchoring node 6 by bolts.

[0029] In this technical solution, the C-shaped mesh outer plate body 52 cooperates with the vertical flange plates 521 to form a strong bending-resistant cross-section, which significantly improves the rigidity of the plate body, the connecting piece 41 realizes quick and adjustable connection with the flange plates 521 by bolts, the symmetrically arranged fixed sleeves 412 can accurately guide the force transmission direction of the main rod piece 42, ensuring that the pulling force is transmitted to the anchoring nodes 6 along the designed angle, the main rod piece 42 is respectively inserted into the fixed sleeves 412 and bolted with the connecting supports 63, forming a double force transmission mechanism of “insertion + bolt”, which not only ensures convenient installation, but also provides a reliable rigid joint node, greatly improves the installation accuracy and efficiency, and at the same time ensures that the main rod piece 42 disperses the concentrated load of the grouting anchor cable 2 of the anchoring node 6 to the slope body 1 in the rigid mesh layer and the concrete layer 3.

[0030] In another technical solution, one end of the secondary rod member 43 is detachably connected to the middle part of the main rod member 42, and the other end of the secondary rod member 43 is sleeved with a secondary rod member support 431, and the secondary rod member support 431 is fixed to the inner support frame body 53. In this technical solution, the main rod member 42 and the secondary rod member 43 jointly constitute a spatial force transmission network. During construction, a connection interface is first set in the middle part of the main rod member 42. The connection interface refers to an existing steel structure node form, such as a connection plate with a bolt hole or a sleeve. One end of the secondary rod member 43 is detachably connected to the connection interface through a bolt or a latch, and the other end is inserted into the secondary rod member support 431. The secondary rod member support 431 is preliminarily fixed to the steel pipe 531 or the wave-shaped steel bar 532 of the inner support frame body 53 through binding wires or temporary bolts, forming temporary positioning during the construction stage. At this time, the secondary rod member 43 is in a two-end hinged state. When the concrete layer 3 is constructed, the secondary rod member support 431, the inner support frame body 53, and the end part of the secondary rod member 43 are completely wrapped by sprayed concrete. After the concrete solidifies, the secondary rod member support 431 is embedded and fixed by the concrete, and is converted into a rigid fixed end. The end part of the secondary rod member 43 is bonded with the concrete to form a whole, and the temporary connection between the secondary rod member support 431 and the inner support frame body 53 is replaced by the concrete to form a permanent rigid connection.

[0031] In this technical solution, the stress of the secondary rod member 43 is transmitted to the inner support frame body 53 through the secondary rod member support 431, and then uniformly dispersed to the concrete layer 3 through the steel pipe 531 and the wave-shaped steel bar 532, further realizing the conversion of concentrated stress into multi-point stress on the rigid net rack layer. The connection point of the secondary rod member 43 in the middle part of the main rod member 42 forms an additional fulcrum, effectively shortening the compression free length of the main rod member 42, avoiding the instability of the main rod member 42 when transmitting stress, and optionally, a transverse rod member 44 can be additionally arranged between the connection node of the secondary rod member 43 and the main rod member 42, further improving the overall stress stability.

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

[0033] In another technical solution, the anchoring node 6 comprises a node outer cylinder 61 and a node inner cylinder 62, the node outer cylinder 61 is a hexagonal cylinder, and each outer surface is provided with one connecting support 63; the node inner cylinder 62 is a truncated cone cylinder, and the small bottom is directed to the slope body 1; the outer wall of the node inner cylinder 62 is connected with the inner wall of the node outer cylinder 61 through a patch plate; a steel strand fixing seat 64 is matched and accommodated in the node inner cylinder 62; the steel strand fixing seat 64 is provided with a plurality of through holes 641, and the through holes 641 correspond to the steel strands 23 of the grouting anchor cable 2 one by one; in this technical solution, the anchoring node 6 adopts a double-layer cylinder composite structure, the inner conical surface of the node inner cylinder 62 matches the outer conical surface of the steel strand fixing seat 64, the node inner cylinder 62 collects the dispersed tension of the steel strands 23 into axial pressure, and the axial pressure is uniformly transmitted to the hexagonal node outer cylinder 61 through the patch plate, so that stress concentration is avoided.

[0034] In another technical solution, the slope body 1 is fixed with a fixed cylinder 7, the grouting anchor cable 23 passes through the fixed cylinder 2, the fixed cylinder 2 partially extends outside the slope body 1, the node inner cylinder 62 extends an extension cylinder 621 towards the slope body 1, the extension cylinder 621 is coaxial with the fixed cylinder 2 and has the same outer diameter, and the two ends of a protection cylinder 8 are respectively matched and sleeved outside the extension cylinder 621 and the fixed cylinder 2; the protection cylinder 8 is provided with an exhaust port 81 and a grouting port 82; in this technical solution, the fixed cylinder 7 is buried after the drilling of the slope body 1 is completed, the grouting anchor cable 2 is arranged in the fixed cylinder 7, the node inner cylinder 62 extends the extension cylinder 621 which has the same diameter as the fixed cylinder 7, and the protection cylinder 8 is sleeved with the extension cylinder 621 and the exposed section of the fixed cylinder 7 at two ends when the protection cylinder 8 is installed, so that a continuous sealed channel is formed, the exhaust port 81 and the grouting port 82 of the protection cylinder 8 are kept unobstructed, and the grouting pipe of the grouting anchor cable 2 extends from the grouting port 82; when the concrete layer 3 is sprayed, the protection cylinder 8 prevents the sprayed concrete from polluting the steel strands 23 and the concrete from flowing into the inside of the drill hole; after the steel strands 23 are tensioned, the grouting port 82 is used for secondary grouting, 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 above-mentioned slope protection structure, and the method comprises the following steps: S1, drill holes in the slope body 1 at equal intervals in the shape of a plum blossom, and sequentially insert the grouting anchor cable 2 into the drill hole and complete the grouting of the anchoring section 201 in the drill hole. Specifically, drill holes are positioned at equal intervals in the shape of a plum blossom on the slope body 1, the end of the drill hole is enlarged, a fixed cylinder 7 is installed at the drill hole opening, the grouting anchor cable 2 is inserted through the fixed cylinder 7 into the drill hole, the grouting anchor cable 2 includes an anchoring expansion structure 21, a steel strand 23, a grouting pipe, and a plurality of supporting sleeves 22, after the grouting anchor cable 2 is installed, the anchoring expansion structure 21 is opened to form a mesh network in the enlarged area at the bottom of the drill hole, and cement slurry is injected into the anchoring section 201 at the bottom of the drill hole through the grouting pipe to embed the front section of the grouting anchor cable 2 in the slope body 1.

[0036] S2, install a rigid mesh layer on the surface of the slope body 1, specifically, the prefabricated mesh 5 is transported to the construction site after being processed in the steel structure processing plant, and is assembled in a hexagonal area unit with each grouting anchor cable 2 as the center, the inner plate body 51 of the mesh is connected to the adjacent inner plate body 51 by bolts, and the outer plate body 52 of the mesh is fixed by bolts, and when assembling, the arc-shaped plates 50 of the three prefabricated meshes 5 are ensured to be enclosed into a circular anchor cable channel, and during the installation of the rigid mesh layer, soil nails or expansion bolts and other structures can be added to the slope body 1 for temporary fixing of the prefabricated mesh 5.

[0037] S3, complete the entire net rack structure and make the steel strand of each grouting anchor cable 2 pass through the corresponding anchoring node 6, specifically, the connecting piece 41 is bolted to the outer plate body 52 of the mesh through the fixed plate 411, the secondary rod piece support 431 is temporarily fixed to the surface of the inner support frame body 53, one end of the main rod piece 42 is inserted into the fixed sleeve 412 of the connecting piece 41, and the other end is bolted to the connecting support 63 of the anchoring node 6, and the two ends of the secondary rod piece 43 are connected to the middle part of the main rod piece 42 and the secondary rod piece support 431 respectively.

[0038] S4, spray concrete on the surface of the slope body 1, and the formed concrete layer 3 completely covers the rigid mesh layer, specifically, the anchoring node 63 is first wrapped with a roll of geotextile to avoid pollution, a protection cylinder 8 is installed to avoid the sprayed concrete from polluting the exposed steel strand 23 and flowing into the drill hole, a wet spraying machine is used to spray concrete layer by layer, and a continuous concrete layer 3 is formed by completely wrapping the rigid mesh layer, the connecting piece 41 and the secondary rod piece support 431, the spraying is pushed from the slope foot to the slope top, the formed concrete layer 3 is combined with the rigid mesh layer to form a composite tensile body, the corrugated reinforcement 532 inhibits concrete shrinkage cracks, the inner plate body 51 of the mesh, the outer plate body 52 of the mesh and the steel pipe 531 improve the overall stiffness, and the secondary rod piece support 431 is solidified by the concrete to become a fixed end.

[0039] S5, pre-stress the steel strand 23 of the grouting anchor cable 2 one by one with the anchoring node 6 as a support, and use the anchoring node 6 as a counterforce support to tension the steel strand 23 with a jack, the tensioning sequence follows the principle of "first middle and then periphery, and symmetrically", the main rod 42 and the secondary rod 43 are compressed and transmit force to the rigid mesh layer and the concrete layer 3 to cooperatively apply surface pressure to the surface of the slope body 1.

[0040] S6, secondary grouting is performed in the drill hole, the free section 202 in the drill hole is closed, micro-expansion slurry is injected into the free section 202 through the grouting port 82 of the casing 8, and the air and residual water are discharged through the exhaust port 81, the grouting pressure is 0.3-0.5 MPa until fullness, and the slurry forms a full-length bonded anchor cable after hardening.

[0041] In another technical solution, after the grouting of the anchoring section 201 in the drill hole is completed in step S1, a row of grouting flower pipes is punched into the slope from top to bottom on both sides of each row of anchoring sections 201, and pressure grouting is performed on the grouting flower pipes, and the resulting rock mass covers the anchoring section 201. In this technical solution, the grouting flower pipe construction is implemented after the anchoring section 201 is initially set, and the resulting rock mass eliminates the weak contact zone between the anchoring section 201 and the stratum, and converts the point anchoring into a columnar composite anchoring body, and the ultimate uplift capacity of the grouting anchor cable 2 is improved. Exemplarily, the grouting flower pipe hole positions are located 0.5 m away from the center line of each row of anchoring sections 201, the holes are formed vertically to the slope surface by impact drilling, the seamless steel pipes with tapered heads and annular slurry outlets are quickly inserted as the grouting flower pipes, the bottom ends of the grouting flower pipes are extended below the bottom of the anchoring section 201 at the lowest position, and the pipe openings of the grouting flower pipes are connected to the grouting equipment. The ultra-fine cement-based slurry is injected at a high pressure of 0.8-1.2 MPa, the grouting flow rate is controlled to be 15-20 L / min, the grouting is terminated when the slurry returns from the adjacent hole positions or the slope surface locally rises, the slurry diffuses and penetrates along the rock-soil cracks, and the continuous and dense rock mass is formed after 24 hours of hardening.

[0042] It should be noted that although the above describes the steps in a specific order, it does not mean that the steps must be performed in the above specific order, in fact, some of the steps can be performed concurrently or even in a changed order, as long as the required functions can be achieved. The number of devices and the processing scale described herein are used to simplify the description of the present application, and the application, modification and change of the present application are obvious to those skilled in the art.

[0043] Although the embodiments of the present application have been disclosed as above, they are not limited to the application and implementation listed in the specification, and can be fully applied to various fields suitable for the present application, and additional modifications can be easily realized by those skilled in the art, therefore, the present application is not limited to specific details and the figures shown and described herein, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. Slope protection structure, characterized in that: include: A concrete layer (3) formed on the slope surface of the slope (1); A plurality of grouting anchor cables (2) are arranged in a matrix on the slope (1), the front portions of the grouting anchor cables (2) are embedded in the interior of the slope (1), and the free ends of the grouting anchor cables (2) extend outward from the concrete layer (3); A rigid mesh layer, wherein the rigid mesh layer is a rigid mesh structure covering the entire surface of the slope (1); A grid structure (4) includes anchor nodes (6) corresponding one to one with grouting anchor cables (2), wherein the free ends of the grouting anchor cables (2) are anchored on the anchor nodes (6), and any anchor node (6) is radially connected to a plurality of main rods (42) in the direction of the slope (1), and the other ends of the plurality of main rods (42) are connected to the rigid mesh layer and buried in the concrete layer (3), and the connection points between the main rods (42) and the rigid mesh layer are distributed in a matrix manner; The tensioning force generated by the single grouting anchor cable (2) is uniformly applied to the surface of the slope (1) through the anchoring node (6), the main rod (42), the rigid mesh layer, and the concrete layer (3) in sequence.

2. The slope protection structure according to claim 1, characterized in that: A plurality of grouting anchor cables (2) are arranged in a plum blossom shape with equal intervals, and a plurality of equal hexagonal regional units of the same size are divided with each grouting anchor cable (2) as the center. The rigid mesh layer in each regional unit is composed of three prefabricated meshes (5) spliced ​​together. The prefabricated meshes (5) are parallelograms with an obtuse angle concave inward. The prefabricated meshes (5) include two mesh inner plates (51) and two mesh outer plates (52). The prefabricated meshes (5) in the same regional unit are detachably connected to each other through the mesh inner plates (51). The prefabricated meshes (5) in adjacent regional units are detachably connected through the mesh outer plates (51). A concave arc plate (50) is provided at the joint of the two mesh inner plates (51). The circular area formed by splicing the arc plates (50) of the three prefabricated meshes (5) passes through the grouting anchor cable (2).

3. The slope protection structure according to claim 2, characterized in that: The prefabricated mesh (5) also includes an inner support frame (53), and the inner support frame (53) includes a plurality of parallel steel pipes (531), one end of each steel pipe (531) is fixed to one of the mesh inner plates (51), and the other end is fixed to the opposite mesh outer plate (52), and a wavy steel bar (532) is provided between the adjacent plurality of steel pipes (531).

4. The slope protection structure according to claim 3, characterized in that: The mesh outer plate body (52) is C-shaped, wherein the two long sides of the mesh outer plate body (52) are vertically bent to form flange plates (521) on one side of the center of the corresponding regional unit, and screw holes are provided on the flange plates (521). A connecting member (41) is provided in the middle of the two connected mesh outer plate bodies (52), and the connecting member (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), and the fixing sleeves (412) are respectively inclined toward the anchoring nodes (6) of the corresponding side regional units. The anchoring nodes (6) include six connecting supports (63) arranged around the circumference, and the surfaces of the connecting supports (63) opposite to the fixing sleeves (412) are provided with threaded through holes. One end of the main rod (42) is matched and inserted into the fixing sleeve (412), and the other end is bolted to the corresponding connecting support (63).

5. The slope protection structure according to claim 4, characterized in that: The middle portion of the main rod (42) is detachably connected to one end of a secondary rod (43), and the other end of the secondary rod (43) is sleeved with a secondary rod support (431), and the secondary rod support (431) is fixed on the inner support frame (53).

6. The slope protection structure according to claim 5, characterized in that: The secondary rod support (431) and the connecting member (41) are both buried inside the concrete layer (3).

7. The slope protection structure according to claim 4, characterized in that: The anchoring node (6) comprises a node outer tube (61) and a node inner tube (62), wherein the node outer tube (61) is a hexagonal cylinder, and each outer surface thereof is provided with a connection support (63), and the node inner tube (62) is a frustum-shaped cylinder, and its small bottom faces the slope (1), and the outer wall of the node inner tube (62) is connected to the inner wall of the node outer tube (61) by a plate, and a steel strand fixing seat (64) is matched and accommodated in the node inner tube (62), and the steel strand fixing seat (64) is provided with a plurality of through holes (641), and the through holes (641) correspond one-to-one to the steel strands (23) of the grouting anchor cable (2).

8. The slope protection structure according to claim 7, characterized in that: A fixed tube (7) is fixed on the slope body (1), the grouting anchor cable (23) passes through the fixed tube (2), the fixed tube (2) partially extends outside the slope body (1), the node inner tube (62) extends an extension tube (621) in the direction of the slope body (1), the extension tube (621) and the fixed tube (2) are coaxial and have the same outer diameter, the two ends of the casing (2) are respectively matched and sleeved on the outside of the extension tube (621) and the fixed tube (2), and the casing (2) is provided with an exhaust port (81) and a grouting port (82).

9. A slope protection structure construction method, applied to the slope protection structure according to claim 8, characterized in that: The following steps are involved: S1, drilling holes into the slope (1) in a plum blossom-shaped arrangement with equal spacing, inserting grouting anchor cables (2) into the holes one by one and completing grouting of the anchoring sections (201) in the holes; S2, installing a rigid mesh layer on the surface of the slope (1); S3, completing the entire grid structure (4) and ensuring that the steel strands (23) of each grouting anchor cable (2) are inserted into the corresponding anchoring nodes (6); S4, spraying concrete onto the surface of the slope (1), so that the formed concrete layer (3) completely covers the rigid mesh layer; S5, applying prestress to the steel strands (23) of the grouting anchor cable (2) one by one using the anchor nodes (6) as supports; S6. Perform secondary grouting into the borehole to seal the free section (202) in the borehole.

10. The slope protection structure construction method according to claim 9, characterized in that: In step S1, after completing the grouting of the anchoring section (201) in the borehole, a row of grouting flower tubes are driven from top to bottom on both sides of each column of anchoring sections (201), and the grouting flower tubes are pressure-grouted. The stone body formed by the pressure grouting covers the anchoring section (201).

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