A secondary grouting blocking device suitable for large deformation anchor cable

Abstract

The application provides a secondary grouting blocking device suitable for large deformation anchor cables, which comprises a dynamic slidable sealing ring, the dynamic slidable sealing ring comprises a dynamic sealing unit, a low-friction bushing, a rigid sealing disc, a ring shell and a static sealing unit which are sequentially nested from inside to outside; the ring shell is internally provided with the rigid sealing disc, the rigid sealing disc is provided with a central sliding channel and two eccentric overflow channels; the low-friction bushing is embedded in the central sliding channel, and the dynamic sealing unit is mounted on the inner side of the low-friction bushing; the application realizes the compatibility of dynamic sealing and large axial displacement; the dynamic slidable sealing ring allows the anchor cable to freely slide while keeping sealing, fundamentally overcomes the destructive shearing effect of large deformation on the grouting ring, and makes the application of secondary grouting on NPR anchor cables possible; integrated design and modular integration are adopted, which is convenient for quality control and on-site installation.

Description

Technical Field

[0001] This application relates to the field of secondary grouting technology, and in particular to a secondary grouting sealing device suitable for anchor cables with large deformation. Background Technology

[0002] As underground engineering continues to advance into deeper strata, the surrounding rock of underground structures such as roadways and tunnels often exhibits complex large deformation characteristics, such as large deformation of soft rock, large deformation of rock bursts, large deformation of impact, and large deformation of gas coupling, which puts forward higher requirements for the deformation adaptability and anchoring performance of the surrounding rock support system.

[0003] Traditional prestressed anchor cables are mostly made of high-strength steel strands. They rely on the bonding effect between the grout and the soil and rock mass, and achieve soil and rock stability by applying prestress. However, they have poor ductility and are prone to brittle fracture when the stress exceeds the limit. They cannot adapt to the large deformation characteristics of the strata and are prone to sudden failure in engineering scenarios such as landslides and soft rock tunnels with large deformation, which can lead to catastrophic engineering consequences. They are difficult to meet the support requirements of deep large deformation surrounding rock.

[0004] NPR anchor bolts (publication number CN211038693U), as constant-resistance large-deformation anchor bolts with negative Poisson's ratio effect, can interact with the rock mass and undergo synergistic deformation after being embedded in the rock mass with an anchoring agent, forming NPR rock mass. This effectively improves the mechanical conditions of the surrounding rock and adapts to the large-deformation support requirements of deep engineering, becoming an important technical means for deep surrounding rock support. The NPR anchor bolt includes a rod body, a tray, and a locking device. The rod body is an NPR spiral steel bar, and the tray and the locking device are directly fitted onto the tail of the NPR spiral steel bar. The NPR anchor cable designed based on the NPR anchor bolt inherits the large-deformation adaptability characteristics of NPR material, becoming a preferred solution for anchor cable support in deep large-deformation surrounding rock.

[0005] To enhance the anchoring force of anchor cables, especially to meet the anchoring requirements of soft strata, the industry has developed secondary high-pressure grouting technology. This technology involves pre-embedding a grouting pipe with a sleeve valve within the borehole and performing high-pressure fracturing grouting after the initial grout has set. This creates expanded, root-like grout veins in the anchoring section of the anchor cable, significantly improving the bond strength between the anchor cable and the stratum. It is a key technology for enhancing anchor cable anchoring performance. The core device of secondary high-pressure grouting technology is a sealing device (grout stop ring), whose primary function is to effectively isolate the anchoring section from the free section after secondary grouting, preventing grout leakage and ensuring the effectiveness of the secondary high-pressure grouting process.

[0006] Traditional grout sealing rings in existing technologies mainly rely on rigid fixation to the borehole wall to achieve a sealing effect. When used in conjunction with NPR anchor cables, the NPR anchor cables will undergo large axial deformations of up to several hundred millimeters during the support process. This deformation will generate huge shear forces on the traditional grout sealing ring, which can easily cause shear failure of the grout sealing ring and seal failure. This will lead to the inability to carry out secondary grouting normally or serious grout leakage problems. At the same time, the deformation adaptability of ordinary grouting pipes is insufficient. Under the large deformation conditions of NPR anchor cables, they are easily broken, directly causing the failure of the entire grouting system.

[0007] To address the aforementioned issues, this application provides a secondary grouting sealing device capable of adapting to the massive axial displacement of NPR anchor cables. This device ensures that the secondary high-pressure grouting function can be effectively established and maintained in a sealed manner before and after the anchor cable undergoes large deformation, thereby achieving a perfect combination of high anchoring force and large deformation capacity. Summary of the Invention

[0008] The purpose of this application is to provide a secondary grouting sealing device suitable for anchor cables with large deformation, so as to solve or alleviate the problems existing in the prior art.

[0009] To achieve the above objectives, this application provides the following technical solution: A secondary grouting sealing device suitable for anchor cables with large deformation includes a dynamic sliding sealing ring, wherein the dynamic sliding sealing ring includes a dynamic sealing unit, a low friction bushing, a rigid sealing disc, a ring housing, and a static sealing unit arranged in sequence from the inside to the outside. The ring housing is provided with a rigid sealing disc, which has a central sliding channel and two eccentrically positioned eccentric flow channels. The central sliding channel is used for the NPR anchor cable to pass through, and the two eccentric flow channels are used for the primary grouting pipe and the secondary grouting pipe to pass through, respectively. The low-friction bushing is embedded in the central sliding channel, and a dynamic sealing unit is installed on the inner side of the low-friction bushing. The dynamic sealing unit consists of multiple wear-resistant, highly elastic lip-shaped rubber sealing rings, which provide continuous dynamic sealing during the sliding of the NPR anchor cable. The static sealing unit is made of water-stopping and sealing rubber material and is fixedly sleeved on the outside of the rigid sealing disc to achieve static sealing between the ring housing and the borehole wall.

[0010] Furthermore, the static sealing unit is made of water-swellable rubber material, and the initial outer diameter of the static sealing unit is 0.95-1.00 times the borehole diameter.

[0011] Furthermore, the static sealing unit is made of high-strength compression rubber, and the initial outer diameter of the static sealing unit is 1.03-1.08 times the borehole diameter.

[0012] Furthermore, the ring housing and the rigid sealing disc are integral structures. The ring housing is made of Q235B carbon structural steel to facilitate the processing, manufacturing, and welding of auxiliary components. The rigid sealing disc is made of low-alloy structural steel with mechanical properties no less than Q355B to ensure its strength and rigidity as the core load-bearing structure.

[0013] Furthermore, the low-friction bushing is made of polytetrafluoroethylene or is an oil-impregnated bearing; the low-friction bushing allows the NPR anchor cable to slide axially with low resistance within the ring housing.

[0014] Furthermore, the dynamic sliding sealing ring also includes a smooth transition conduit, which is made of steel and its outer surface is finely ground and polished before being electroplated with hard chrome; the chrome plating thickness is not less than 30μm, the surface hardness is not less than HV800, and the surface roughness Ra is not greater than 0.4μm; the length of the conduit is determined according to the design deformation of the anchor cable; the smooth transition conduit wraps around and fixes the NPR anchor cable, and the length of the smooth transition conduit covers the maximum deformation stroke of the NPR anchor cable; the smooth transition conduit is fixedly sleeved on the NPR anchor cable, providing a smooth and wear-resistant sliding surface for the sealing ring.

[0015] Furthermore, the dynamic sliding sealing ring also includes a centering bracket installed on the outer periphery of the rigid sealing disc, wherein at least a portion of the centering bracket's structure radially protrudes from the outer contour of the static sealing unit; the centering bracket is used to maintain the centering position of the ring housing within the borehole.

[0016] Furthermore, the secondary grouting pipe includes a straight section and a pre-deformed section. The pre-deformed section is wavy, spiral, or has a redundant loop with a sufficient reserved length. The pre-deformed section is placed inside a flexible protective sleeve.

[0017] Furthermore, the secondary grouting sealing device suitable for large deformation anchor cables also includes a guide cap that can cover the ends of the NPR anchor cable, the primary grouting pipe, and the secondary grouting pipe.

[0018] Furthermore, the secondary grouting sealing device for anchor cables with large deformation also includes an exhaust channel set on a rigid sealing disc, and the exhaust channel is sealed and connected to an exhaust pipe.

[0019] The technical solution of this application has the following beneficial effects: This application proposes a dynamic sliding sealing ring hoop, which achieves compatibility between dynamic sealing and large axial displacement through the division of labor and cooperation of static sealing, sliding bearing and dynamic sealing. The dynamic sliding sealing ring hoop allows the anchor cable body to slide freely while maintaining a seal, fundamentally overcoming the destructive shear effect of large deformation on the grout stop ring, making the application of secondary grouting on NPR anchor cables possible. This application adopts an integrated design and modular integration, which facilitates quality control and on-site installation, reduces human interference, and ensures the reliability of complex technical measures. This application combines the two major technical advantages of NPR anchor cables' large deformation energy absorption and secondary grouting's high-strength anchoring, forming a support system of "strong anchoring and flexible deformation", which is particularly suitable for controlling extreme geological disasters such as high-speed landslides and heavily mined roadways. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. Wherein: Figure 1 This is a schematic diagram of the front cross-sectional structure according to an embodiment of the present invention.

[0021] Figure 2 This is a cross-sectional view of an embodiment of the present invention along the vertical plane.

[0022] Figure 3 This is an assembly diagram of an embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram showing the arrangement of the pre-deformation section before deformation of the secondary grouting pipe in an embodiment of the present invention.

[0024] Figure 5 This is a schematic diagram of the arrangement of the pre-deformed section after the deformation of the secondary grouting pipe in an embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures: 1-Plate, 2-Anchor, 3-NPR anchor cable, 4-Primary grouting pipe, 5-Secondary grouting pipe, 51-Pre-deformed section, 6-Protective sleeve, 7-Protective sleeve, 8-Exhaust pipe, 9-Dynamic sealing ring, 10-Hole wall, 11-Guide cap, 91-Static sealing unit, 92-Centering bracket, 93-Ring housing, 94-Rigid sealing disc, 95-Smooth transition guide, 96-Dynamic sealing unit, 97-Eccentric flow channel, 98-Low friction bushing, 99-Exhaust channel, 100-Concrete pier. Detailed Implementation

[0026] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present application without departing from the scope or spirit thereof. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present application encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing embodiments of this disclosure only and is not intended to limit this disclosure.

[0028] In the description of this application, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and do not require this application to be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0029] like Figures 1 to 5 As shown, a secondary grouting sealing device suitable for anchor cables with large deformation includes a dynamic sliding sealing ring, which includes a dynamic sealing unit 96, a low friction bushing 98, a rigid sealing disc 94, a ring housing 93, and a static sealing unit 91 arranged in sequence from the inside to the outside. A rigid sealing disc 94 is provided inside the ring housing 93. The rigid sealing disc 94 is provided with a central sliding channel and two eccentrically positioned eccentric flow channels 97. The central sliding channel is used for the NPR anchor cable 3 to pass through, and the two eccentrically positioned flow channels 97 are used for the primary grouting pipe 4 and the secondary grouting pipe 5 to pass through, respectively. The low-friction bushing 98 is embedded in the central sliding channel, and a dynamic sealing unit 96 is installed on the inner side of the low-friction bushing 98. The dynamic sealing unit 96 is composed of multiple wear-resistant and highly elastic lip-shaped rubber sealing rings, and the dynamic sealing unit 96 provides continuous dynamic sealing during the sliding of the NPR anchor cable 3. The static sealing unit 91 is made of water-stopping and sealing rubber material and is fixedly sleeved on the outside of the rigid sealing disc 94 to achieve static sealing between the ring housing 93 and the borehole wall 10.

[0030] Furthermore, such as Figure 1 , Figure 2 As shown, the dynamic sealing unit 96 consists of at least two lip-shaped rubber sealing rings, with a lubrication cavity formed between adjacent lip-shaped rubber sealing rings, filled with grease. All sealing rings have their lips facing the bottom of the borehole, allowing them to adhere more tightly to the outer wall of the smooth transition conduit 95 under secondary grouting pressure, forming a pressure-activated dynamic seal. The lip-shaped rubber sealing rings are made of wear-resistant, pressure-resistant, and alkali-resistant elastic materials, such as hydrogenated nitrile rubber, polyurethane rubber, or fluororubber; their Shore hardness is recommended to be between 80A and 90A, balancing sealing performance, conformability, and wear resistance.

[0031] Furthermore, the static sealing unit 91 is made of water-swellable rubber material, and the initial outer diameter of the static sealing unit 91 is 0.95-1.00 times the borehole diameter. Alternatively, the static sealing unit 91 is made of high-strength compression rubber, and the initial outer diameter of the static sealing unit 91 is 1.03-1.08 times the borehole diameter.

[0032] Furthermore, the ring housing 93 and the rigid sealing disc 94 are both integral structures. The ring housing 93 is made of Q235B carbon structural steel to facilitate the processing, manufacturing, and welding of auxiliary components. The borehole wall 10 is often uneven, and the static sealing unit 91 experiences uneven pressure from the borehole wall 10 when expanding or under pressure. As an integral cylinder, the ring housing 93 can homogenize and absorb these uneven radial forces, preventing these irregular forces from being directly transmitted to the internal rigid sealing disc 94 and precision sliding sealing components, thereby ensuring their coaxiality and smooth sliding. It also serves as a fixed carrier for the centering support 92. The rigid sealing disc 94 is made of low-alloy structural steel with mechanical properties no lower than Q355B to ensure its strength and rigidity as the core load-bearing structure.

[0033] Furthermore, the low-friction bushing 98 is made of polytetrafluoroethylene or is an oil-impregnated bearing; the low-friction bushing 98 allows the NPR anchor cable 3 to slide axially with low resistance within the ring housing 93; the low-friction bushing 98 is designed to guide rather than seal; the low-friction bushing 98 has a length of 80-100 mm, which is sufficient to provide good guidance while keeping the frictional resistance within a reasonable range.

[0034] Furthermore, the dynamic sliding sealing ring also includes a smooth transition conduit 95, which is made of steel, such as No. 45 steel, and its outer surface is finely ground and polished before being electroplated with hard chrome; the chrome plating thickness is not less than 30μm, the surface hardness is not less than HV800, and the surface roughness Ra is not greater than 0.4μm; the length of the conduit is determined according to the design deformation of the anchor cable; preferably, the wall thickness of the smooth transition conduit 95 is 4mm, and the length of the smooth transition conduit 95 is 400mm to 600mm.

[0035] The smooth transition conduit 95 is fixedly sleeved on the NPR anchor cable 3, only covering the section of the NPR anchor cable 3 that needs to participate in sliding and receive sealing, thereby providing a smooth, wear-resistant sliding surface for the dynamic sealing unit 96. Assuming the maximum deformation stroke of the anchor cable is ΔL (e.g., 300mm), and the low-friction bushing length L... ct (e.g., 25mm), smooth transition conduit length L dg Must satisfy: L dg ≥ΔL+L ct+Safety margin; the safety margin is 10%-15% of the maximum deformation stroke of the anchor cable; this is to ensure that, throughout the entire process of the anchor cable sliding from its initial position to its maximum stroke, the lip of the dynamic sealing ring is always and completely in contact with the outer wall of the smooth transition conduit 95, and never comes into contact with the rough, irregular anchor cable strand body. Specifically, the smooth transition conduit 95 forms a coaxial, firm, and sealed fixed connection with the NPR anchor cable 3 body through interference fit crimping and supplemented by end sealing welding, ensuring that the two move as a whole when under tension, and there is no path for grout leakage; the smooth transition conduit 95, together with the dynamic sealing structure, solves the problem of not being able to achieve high-pressure dynamic sealing on the steel strand.

[0036] Preferred, such as Figure 1 , Figure 2 As shown, the dynamic sliding sealing ring also includes a centering bracket 92 installed on the outer periphery of the rigid sealing disc 94. The centering bracket 92 includes an annular portion that wraps around and is fixed to the outer periphery of the sealing ring / rigid sealing disc 94 and several legs that are uniformly fixed to the outer periphery of the annular portion. The free ends of the legs extend beyond or are flush with the outer contour of the static sealing unit 91, so that the free ends of the legs can directly contact the borehole wall 10 to initially position and maintain the centering position of the ring within the borehole. During installation, the device is placed into the borehole. The legs of the centering bracket 92 first contact the irregular borehole wall 10, pushing the device to a position centered relative to the borehole. Subsequently, the static sealing unit 91 undergoes radial deformation under pressure or upon contact with water, filling the gaps between the legs and the gap with the borehole wall 10, achieving final sealing. At this point, although the legs may be partially wrapped by the static sealing unit 91, the initial centering task has been completed.

[0037] Furthermore, such as Figure 2 As shown, the secondary grouting pipe 5 includes a straight section and a pre-deformed section 51. The pre-deformed section 51 is wavy, spiral, or has a redundant ring with a sufficient reserved length. The pre-deformed section 51 is placed inside a flexible protective sleeve 6 to prevent it from being stuck during installation. Figure 4 The diagram shows the arrangement of the pre-deformation section 51 before the deformation of the secondary grouting pipe 5. Figure 5This diagram illustrates the arrangement of the pre-deformed section 51 after the secondary grouting pipe 5 deforms. When the NPR anchor cable 3 experiences a large axial displacement under tension, the pre-deformed section is gradually straightened, converting its reserved geometric length into a compensation length. This effectively absorbs the tensile stress generated by the elongation of the NPR anchor cable 3 on the secondary grouting pipe 5, ensuring the integrity and reliability of the secondary grouting channel throughout the entire large deformation process. When the NPR anchor cable 3 deforms under tension, the pre-set corrugated or looped sections are gradually straightened, compensating for the tensile stress generated by the anchor cable elongation on the grouting pipe and preventing plastic stretching or breakage of the pipeline. The protective sleeve 6 is made of corrosion-resistant and wear-resistant high-molecular polymer material. The inner diameter of the protective sleeve 6 is 15%-25% larger than the maximum outer diameter of the secondary grouting pipe 5 after coiling. Preferably, a high-density polyethylene double-wall corrugated pipe is used, with an inner diameter of 20%, possessing excellent ring stiffness and flexibility, effectively resisting mechanical damage within the borehole.

[0038] Priority is that the straight section and the pre-deformed section 51 of the secondary grouting pipe 5 are independent of each other. The straight section and the pre-deformed section 51 of the secondary grouting pipe 5 are respectively connected to the corresponding eccentric flow channel 97 through threads or quick-connect couplings. In this way, the tensile and compressive forces borne by the grouting pipeline are borne by the rigid sealing disc 94, avoiding the problem of loose structure.

[0039] Furthermore, such as Figure 3 As shown, the secondary grouting sealing device for large deformation anchor cables also includes a guide cap 11 that can cover the ends of the NPR anchor cable 3, the primary grouting pipe 4, and the secondary grouting pipe 5. The guide cap 11 has a socket post inside for the end of the NPR anchor cable 3 to be inserted. The guide cap 11 gathers the primary grouting pipe 4, the secondary grouting pipe 5, and the NPR anchor cable 3 into a whole; when lowering the anchor cable, the guide cap 11 can guide the anchor cable to smoothly enter the borehole, preventing the ends of the primary grouting pipe 4, the secondary grouting pipe 5, and the NPR anchor cable 3 from directly scraping the borehole wall 10.

[0040] Furthermore, the secondary grouting sealing device suitable for large deformation anchor cables also includes an exhaust channel 99 disposed on a rigid sealing disc 94, wherein an exhaust pipe 8 is sealed and connected to the exhaust channel 99. During grouting, the exhaust pipe 8 needs to be led out of the borehole.

[0041] This application allows for direct field use after factory assembly. The device employs a modular design; core functional modules should be pre-assembled and tested in the factory to ensure reliable quality. The assembly steps are as follows: (1) Core skeleton assembly: The rigid sealing disc 94 is inserted into the ring housing 93 with an interference fit and fixed by end circumferential welding or bolts; the low friction bushing 98 is pressed into the central sliding channel of the rigid sealing disc 94.

[0042] (2) Installation of sealing unit: The dynamic sealing unit 96, composed of multiple lip-shaped rubber sealing rings, is sequentially installed into the central channel of the rigid sealing disc 94, ensuring that all lips face the same side; the lubrication cavity between the sealing rings is filled with special grease.

[0043] (3) Sealing pipeline connection: Protect and bind the pre-deformed section 51 of the secondary grouting pipe 5 with a protective sleeve 6; pass the free ends of the primary grouting pipe 4, the secondary grouting pipe 5 and the exhaust pipe 8 through the corresponding eccentric flow channel 97 and exhaust channel 99 on the rigid sealing plate 94 respectively, and use a threaded clamping joint with a sealing ring to tighten and seal both ends of the eccentric flow channel 97 and the exhaust channel 99.

[0044] (4) Integration of peripheral components: Reserve a preset position for the centering bracket 92, press the static sealing unit 91 into the outer periphery of the ring housing 93; then weld or bond the centering bracket 92 to the preset position on the outer wall of the ring housing 93.

[0045] (5) Modular packaging: The protective pipe, secondary grouting pipe 5, primary grouting pipe 4 and exhaust pipe 8 are loosely tied with nylon cable ties and labeled to obtain a dynamic sliding sealing ring hoop (hereinafter referred to as functional module) assembled with exhaust pipe 8, primary grouting pipe 4, secondary grouting pipe 5 and protective pipe.

[0046] The on-site installation and construction steps for the functional modules are as follows: (1) Drilling and cleaning: Drill holes according to design requirements and clean them thoroughly with high-pressure air or water.

[0047] (2) Anchor cable and functional module assembly: The starting point of the designed anchorage section is precisely marked on the NPR anchor cable 3 body; Slide the smooth transition conduit 95 onto the NPR anchor cable 3, move the smooth transition conduit 95 in the functional module to the marked point, use a large-tonnage hydraulic clamp to perform radial crimping, and then perform sealing welding between the two ends of the smooth transition conduit 95 and the NPR anchor cable 3 body to ensure a firm connection and no leakage path. The free section of the module is laid straight along the anchor cable body and sparsely fixed with cable ties.

[0048] (3) Install end components: Install guide cap 11 at the end of NPR anchor cable 3 and fasten it to NPR anchor cable 3 with stainless steel hose clamp at the socket post inside the guide cap 11; insert the free ends of primary grouting pipe 4 and secondary grouting pipe 5 into guide cap 11 to obtain the assembled anchor cable system. (4) Overall cable lowering: The assembled anchor cable system is slowly and evenly inserted into the borehole until the design depth is reached; the centering bracket 92 is used to guide and center the installation to ensure smooth installation. (5) Casting concrete pier 100: Formwork is erected at the opening and concrete pier 100 is cast; during casting, an extension pipe extending out of the pier is connected to the free end of the primary grouting pipe 4; the secondary grouting pipe 5 and the exhaust pipe 8 extend to the outside through the protective sleeve 7 embedded in the concrete pier 100; an outlet valve is installed on the exhaust pipe 8. (6) First grouting and curing: After the pier concrete reaches a certain strength, grouting is started from the bottom of the hole through the extension pipe and the first grouting pipe 4 until homogeneous grout returns from the hole opening, and then the extension pipe is removed; during the first grouting process, venting is assisted by the vent pipe 8 to ensure that the grouting is dense. Static curing is carried out until the first grouting body reaches more than 70% of the design strength.

[0049] (7) Secondary high-pressure grouting: Connect the secondary grouting pipe 5 to the high-pressure grouting pump. Open the outlet valve of the exhaust pipe 8 and start the grouting pump. After the air is discharged from the exhaust pipe 8 and homogeneous grout flows out, close the outlet valve of the exhaust pipe 8. Continue to pressurize to the design splitting pressure and stabilize the pressure for the specified time. During this period, the static sealing unit 91 ensures the seal between the ring and the hole wall 10, and the dynamic sealing unit 96 ensures the seal of the anchor cable sliding surface.

[0050] (8) Tensioning, locking, and system operation: After the secondary grout reaches the required strength, a steel pad is installed on the concrete pier 100. The NPR anchor cable 3 is then subjected to the design prestress using a tensioning device and locked through the anchor 2 and the tray 1. When the surrounding rock deforms and causes the anchor cable to elongate under stress, the smooth transition guide 95 slides within the dynamic sealing ring 9, and the pre-deformed section 51 of the free section grouting pipe is straightened to absorb the displacement. The system maintains anchoring force and sealing throughout the entire process.

[0051] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A secondary grouting sealing device suitable for anchor cables with large deformation, characterized in that: It includes a dynamic sliding sealing ring, which includes a dynamic sealing unit (96), a low friction bushing (98), a rigid sealing disc (94), a ring housing (93), and a static sealing unit (91) arranged in sequence from the inside to the outside. The ring housing (93) is provided with a rigid sealing disc (94), and the rigid sealing disc (94) is provided with a central sliding channel and two eccentrically arranged eccentric flow channels (97); the central sliding channel is used for the NPR anchor cable (3) to pass through, and the two eccentric flow channels (97) are used for the primary grouting pipe (4) and the secondary grouting pipe (5) to pass through, respectively; the low friction bushing (98) is embedded in the central sliding channel, and a dynamic sealing unit (96) is installed on the inner side of the low friction bushing (98). The dynamic sealing unit (96) is composed of multiple wear-resistant and highly elastic lip-shaped rubber sealing rings, and the dynamic sealing unit (96) provides a continuous dynamic seal during the sliding of the NPR anchor cable (3); The static sealing unit (91) is made of water-stop sealing rubber material and is fixedly sleeved on the outside of the rigid sealing disc (94) to achieve static sealing between the ring housing (93) and the borehole wall (10).

2. The secondary grouting sealing device for anchor cables with large deformation according to claim 1, characterized in that: The static sealing unit (91) is made of water-swellable rubber material, and the initial outer diameter of the static sealing unit (91) is 0.95-1.00 times the borehole diameter.

3. The secondary grouting sealing device for anchor cables with large deformation according to claim 1, characterized in that: The static sealing unit (91) is made of high-strength compression rubber, and the initial outer diameter of the static sealing unit (91) is 1.03-1.08 times the borehole diameter.

4. The secondary grouting sealing device for anchor cables with large deformation according to claim 1, characterized in that: The ring housing (93) and the rigid sealing disc (94) are integral structures. The ring housing (93) is made of Q235B carbon structural steel to facilitate the processing, manufacturing and welding of auxiliary parts. The rigid sealing disc (94) is made of low alloy structural steel with mechanical properties not lower than Q355B to ensure its strength and rigidity as the core load-bearing structure.

5. The secondary grouting sealing device for anchor cables with large deformation according to claim 1, characterized in that: The low-friction bushing (98) is made of polytetrafluoroethylene or is an oil-impregnated bearing; the low-friction bushing (98) allows the NPR anchor cable (3) to slide axially with low resistance within the hoop housing (93).

6. The secondary grouting sealing device for anchor cables with large deformation according to claim 1, characterized in that: The dynamic sliding sealing ring also includes a smooth transition conduit (95), which is made of steel and its outer surface is finely ground and polished and then electroplated with hard chrome. The chrome plating thickness is not less than 30μm, the surface hardness is not less than HV800, and the surface roughness Ra is not greater than 0.4μm. The length of the conduit is determined according to the design deformation of the anchor cable (3). The smooth transition conduit (95) wraps around and fixes the NPR anchor cable (3), and the length of the smooth transition conduit (95) covers the maximum deformation stroke of the NPR anchor cable (3). The smooth transition conduit (95) is fixedly sleeved on the NPR anchor cable (3) to provide a smooth and wear-resistant sliding surface for the sealing ring.

7. The secondary grouting sealing device for anchor cables with large deformation according to claim 1, characterized in that: The dynamic sliding sealing ring also includes a centering bracket (92) installed on the outer periphery of the rigid sealing disc (94). At least part of the structure of the centering bracket (92) protrudes radially from or is flush with the outer contour of the static sealing unit (91). The centering bracket (92) is used to maintain the centering position of the ring housing (93) in the borehole.

8. The secondary grouting sealing device for anchor cables with large deformation according to claim 1, characterized in that: The secondary grouting pipe (5) includes a straight section and a pre-deformed section (51). The pre-deformed section (51) is wavy, spiral, or has a redundant ring with a sufficient length. The pre-deformed section (51) is placed inside a flexible protective sleeve (6).

9. The secondary grouting sealing device for anchor cables with large deformation according to claim 1, characterized in that: The secondary grouting sealing device for large deformation anchor cables also includes a guide cap (11) that can cover the ends of the NPR anchor cable (3), primary grouting pipe (4), and secondary grouting pipe (5).

10. The secondary grouting sealing device for anchor cables with large deformation according to claim 1, characterized in that: The secondary grouting sealing device for anchor cables with large deformation also includes an exhaust channel (99) set on a rigid sealing plate (94), and the exhaust channel (99) is sealed to an exhaust pipe (8).

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