Gradient viscosity layered anchor rod for drainage grouting collaborative control of underground engineering

Abstract

The utility model relates to grouting technical field, especially relate to gradient viscosity layered anchor rod for drainage grouting collaborative control of underground engineering, including outer sleeve tube, the inner core tube of coaxial wear in it and bottom end anchor head, the inner core tube top end is equipped with drainage outlet, and the anchor head is equipped with the drainage hole of intercommunication inner core tube, a plurality of longitudinal partitions are equipped with between outer sleeve tube and inner core tube, and a plurality of mutual non -intercommunication grouting chamber is separated out, each chamber top end independent intercommunication grouting interface, and the grout outlet position is staggered arrangement along the axial direction, and the anchor head is equipped with the grout outlet of intercommunication bottom end chamber, the utility model constructs independent drainage channel to realize initiative depressurization, avoids that grout is diluted by groundwater, simultaneously through the independent chamber accurate delivery different viscosity grout of axial stagger, need not external sealing piece to realize the efficient collaborative operation of drainage and gradient viscosity layered grouting.

Description

Technical Field

[0001] This utility model relates to the field of grouting technology, and in particular to a gradient viscosity layered anchor bolt for coordinated control of drainage grouting in underground engineering. Background Technology

[0002] In underground engineering construction such as traffic tunnel excavation, mine roadway excavation, underground chambers, and drainage tunnels, grouting anchor bolt support is one of the core technical means to control surrounding rock deformation, prevent collapse, and control leakage. Its basic principle is to drill holes in the rock mass, insert anchor bolts into the holes, and inject cement-based or chemical grout into the holes through the bolts. Under pressure, the grout penetrates and fills along the fissures in the surrounding rock, solidifying to form a concretion that tightly bonds the anchor bolts to the surrounding rock, forming an integral load-bearing structure. This achieves the purpose of reinforcing the surrounding rock, controlling deformation, and preventing seepage and water leakage.

[0003] However, existing grouting anchors have the following drawbacks in practical engineering applications, especially under complex geological conditions:

[0004] 1. Simple structure, unable to achieve gradient grouting. Existing grouting anchors (such as segmented or mechanically isolated types) typically only have one grouting channel. This means that during construction, the entire anchor can only be injected with grout of the same viscosity. However, in actual construction, the deep anchoring section at the bottom of the borehole usually requires low-viscosity grout to ensure sufficient penetration, while the borehole sealing section requires high-viscosity grout to prevent backflow. The single-channel structure makes it impossible to use grouts with different performance parameters in different sections, making it difficult to simultaneously meet the needs of deep reinforcement and borehole sealing.

[0005] 2. Incompatible with water-rich environments, making it difficult to guarantee grouting quality. Existing anchor bolts generally lack active drainage and pressure reduction mechanisms. When facing water-rich strata or high-pressure water inflow strata, fissure water in the surrounding rock can seep back into the borehole, causing the injected grout to be diluted, dispersed, or even carried away by high-pressure water before the grout solidifies. This results in insufficient anchor strength, grouting failure, and seriously affects the safety and reliability of the support. Utility Model Content

[0006] The purpose of this invention is to overcome the shortcomings of existing grouting anchors, which are not suitable for water-rich strata and have a single grouting channel that cannot achieve gradient viscosity stratified grouting. This invention provides a gradient viscosity stratified anchor for coordinated control of drainage and grouting in underground engineering.

[0007] In a first aspect, this utility model provides a gradient viscosity layered anchor bolt for coordinated control of drainage and grouting in underground engineering, comprising: Outer tube; The inner core tube is coaxially inserted inside the outer tube, and the top end of the inner core tube is provided with a drain outlet; Multiple longitudinal baffles are disposed in the annular space between the inner wall of the outer sleeve and the outer wall of the inner core tube. The longitudinal baffles extend along the axial direction of the outer sleeve and divide the annular space into multiple non-communicating grouting chambers. The top end of the outer sleeve is provided with a grouting interface that is independently connected to each of the grouting chambers, and the grout outlet positions corresponding to each of the grouting chambers are staggered along the axial direction of the outer sleeve. An anchor head is fixedly connected to the bottom end of the outer sleeve. The anchor head is provided with a drainage hole communicating with the bottom end of the inner core tube, and a grout outlet communicating with the grouting chambers of the plurality of grouting chambers extending to the bottom end of the outer sleeve.

[0008] The gradient viscosity layered anchor bolt for drainage and grouting coordinated control in underground engineering provided by this utility model constructs an independent drainage channel inside the anchor bolt by coaxially arranged inner core tube and drainage hole at the bottom of the anchor head. This achieves active drainage and pressure reduction in water-rich strata, effectively avoiding the defects of grout being diluted and dispersed by high-pressure fracture water in traditional grouting process, and ensuring anchoring quality in complex geological environments.

[0009] Meanwhile, the annular space between the inner and outer pipes is physically divided into multiple non-interconnected grouting chambers by using longitudinal baffles, and the grout outlet positions of each chamber are staggered along the axial direction. Without relying on easily failed sealing components such as external annular grout plugs, grouts of different viscosities and different setting times can be accurately delivered to sections of different depths through their own independent channels, realizing the coordinated operation of drainage and gradient viscosity stratified grouting.

[0010] Preferably, there are three longitudinal partitions, which are arranged circumferentially in the annular space to divide the annular space into a first grouting chamber, a second grouting chamber, and a third grouting chamber.

[0011] This structural design, through the explicit placement of three longitudinal baffles, creates three independent grouting chambers, precisely matching the three-section support requirements of underground engineering grouting construction: "deep penetration at the bottom of the borehole, transitional filling in the middle, and rapid sealing at the borehole opening." This structure allows construction personnel to inject grouts of low, medium, and high viscosities and setting properties into the first, second, and third chambers respectively. This ensures that the low-viscosity, thinner grout can penetrate deep into the micro-cracks at the bottom of the borehole to enhance deep anchoring force, while the high-viscosity, fast-setting, thicker grout can quickly seal the borehole opening to prevent grout leakage. This effectively solves the problem of traditional single-channel anchor bolts, which can only use grout of the same viscosity and cannot simultaneously achieve deep reinforcement and borehole sealing.

[0012] Preferably, the first grouting chamber extends from the top end of the outer sleeve to the bottom end of the outer sleeve, and the bottom end of the first grouting chamber is connected to the grout outlet on the anchor head; a one-way pressure opening valve is provided at the grout outlet of the anchor head; and a one-way drainage valve is provided at the drainage hole on the anchor head.

[0013] With this structural design, the first grouting chamber runs through the entire length of the outer casing and directly connects to the grout outlet of the anchor head. This ensures that the low-viscosity, high-permeability grout can be precisely delivered to the deepest part of the borehole, directly acting on the bottom section, thereby achieving large-scale penetration and cementation of the loose and fractured surrounding rock at the bottom of the borehole. The one-way pressure valve at the grout outlet provides reliable backflow prevention protection. This valve only opens to discharge grout when the preset grouting pressure is reached. Once grouting stops or the pressure inside the borehole fluctuates, the valve automatically closes, effectively preventing high-pressure groundwater or mud and sand from the water-rich strata from invading the first grouting chamber in reverse, thus avoiding blockage of the grouting pipeline. The one-way drainage valve at the drainage hole ensures unobstructed drainage channels, ensuring that the fissure water in the surrounding rock can only flow into the inner core pipe and be discharged outwards in one direction.

[0014] Preferably, the bottom end of the second grouting chamber is provided with a first closed end, and the distance between the first closed end and the anchor head is one-third of the total length of the outer casing.

[0015] By adopting this structural design, the path of the medium-viscosity grout in the second grouting chamber to continue flowing downward is effectively cut off by setting a first closed end at one-third of the length of the anchor head. This forces the grout to be squeezed outward and filled only in the designated middle section. At the same time, this structure forms a reliable physical isolation in the axial direction, preventing cross-contamination between the middle grout and the low-viscosity grout in the deep first chamber at the bottom of the hole.

[0016] Preferably, the side wall of the second grouting chamber is provided with a plurality of lateral grouting holes, and the outer circumference of the outer sleeve is provided with an anti-backflow sleeve valve covering the lateral grouting holes.

[0017] This structural design, by opening lateral grouting holes on the sidewall of the second grouting chamber, alters the flow direction of the grout, enabling radial diffusion of the grout from the middle section to the periphery. This facilitates better filling of the annular gap between the rod and the borehole wall. Simultaneously, an anti-backflow sleeve valve is fitted on the outside to cover the grouting hole. Utilizing the compressive deformation characteristics of elastic rubber, the anti-backflow sleeve valve is opened when grouting pressure is applied, allowing grout to flow out. When grouting stops or external water pressure is too high, the anti-backflow sleeve valve quickly rebounds due to its own elasticity and tightly seals the grouting hole by gripping the pipe wall, achieving "unidirectional radial grout discharge" and effectively preventing backflow of external high-pressure mud or groundwater.

[0018] Preferably, the bottom end of the third grouting chamber is provided with a second closed end, and the distance between the second closed end and the top end of the outer sleeve is 0.5m to 1.0m; the side wall of the third grouting chamber is connected to a grout outlet short pipe, and the diameter of the grout outlet short pipe is larger than the diameter of the lateral grouting hole.

[0019] With this structural design, by setting a second closed end 0.5 to 1.0 m from the top of the outer casing, the third grouting chamber is precisely defined in physical space to serve only the "shallow sealing section of the orifice". The grout outlet short pipe connected to the side wall provides a larger grout outlet cross section compared to the lateral grouting hole, ensuring that the thick grout can be smoothly extruded and quickly accumulate and solidify in the circumferential space of the orifice to form a reliable seal.

[0020] Preferably, a drain control valve and a pressure gauge are connected to the drain outlet of the inner core tube.

[0021] This structural design, by integrating a drainage control valve and a pressure gauge at the outlet of the drainage channel, endows the anchor bolt with the ability to actively sense and regulate the hydrological environment within the borehole. The pressure gauge provides real-time and intuitive feedback on the dynamic changes in the fissure water pressure at the bottom of the borehole, offering accurate data support for setting the grouting timing and pressure. Meanwhile, the drainage control valve allows operators to precisely control the opening and closing of the drainage channel and the flow rate based on the readings, improving the flexibility and scientific nature of the grouting process.

[0022] Preferably, a three-channel rotary distribution joint is installed at the top of the outer casing. The three-channel rotary distribution joint is configured to allow the external grout supply pipeline to selectively connect to any one of the first grouting chamber, the second grouting chamber, or the third grouting chamber through a rotational action.

[0023] This structural design, with a three-channel rotary distribution joint at the top of the outer casing, greatly simplifies the on-site construction process for multi-chamber gradient grouting. Operators can use the rotary joint to sequentially align a single external grout supply pipe with any of the three interfaces, achieving independent grouting switching between the three chambers through rotation, reducing the need for repeated pipe disconnection and reconnection.

[0024] Preferably, it also includes a grout stopper, which is sleeved on the outer circumferential surface of the outer sleeve near the orifice.

[0025] This structural design, by installing a grout-stopping plug around the outer circumference of the outer sleeve near the borehole opening, initially creates a physical sealing barrier at the borehole opening. This grout-stopping plug effectively seals the annular gap between the anchor rod and the borehole wall, preventing a large amount of grout from overflowing directly from the borehole opening during the initial grouting stage.

[0026] Preferably, it further includes a washer and a locking nut, the outer circumference of the top end of the outer tube is provided with threads, the washer is sleeved on the outer tube, and the locking nut is screwed into the threads and abuts against the outside of the washer.

[0027] This structural design, by adding a washer plate and a locking nut mechanical fastening assembly at the tail end of the anchor bolt, can, on the one hand, apply prestress to the anchor bolt after grouting is completed or after consolidation, and evenly transfer and diffuse the fastening load of the nut to the rock surface at the borehole opening through the washer plate, thereby providing active support resistance to the surrounding rock surface and effectively suppressing the initial loosening and deformation of the surrounding rock. On the other hand, the axial thrust generated by tightening the locking nut at the beginning of construction can force the washer plate to press inward against the grout stop plug at the borehole opening, causing the grout stop plug to expand radially under pressure and adhere tightly to the borehole wall, further enhancing the tightness and reliability of the initial physical seal at the borehole opening.

[0028] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. This utility model provides a gradient viscosity layered anchor rod for drainage and grouting coordinated control in underground engineering. By coaxially arranged inner core tube and drainage hole at the bottom of anchor head, an independent drainage channel is constructed inside the anchor rod, thereby realizing active drainage and pressure reduction in water-rich strata. This effectively avoids the defects of grout being diluted and dispersed by high-pressure fracture water in traditional grouting process, and ensures the anchoring quality in complex geological environments. 2. This utility model provides a gradient viscosity layered anchor bolt for coordinated control of drainage and grouting in underground engineering. It uses a longitudinal partition to physically divide the annular space between the inner and outer pipes into multiple non-interconnected grouting chambers. The grout outlet positions of each chamber are staggered along the axial direction. Without relying on easily failed sealing components such as external annular grout plugs, grouts of different viscosities and different setting times can be accurately delivered to sections of different depths through their respective independent channels, realizing the coordinated operation of drainage and gradient viscosity layered grouting. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a gradient viscosity layered anchor structure used for coordinated control of drainage and grouting in underground engineering.

[0030] Figure 2 for Figure 1 Sectional view along the AA direction.

[0031] Figure 3 for Figure 1 Sectional view along the BB direction.

[0032] Figure 4 for Figure 1 Sectional view along the CC direction.

[0033] Figure 5This is a schematic diagram of a three-channel rotary distribution joint.

[0034] Figure 6 This is a schematic diagram showing the effect after grouting.

[0035] Marked in the image: 1-Outer sleeve, 11-First grouting chamber, 12-Second grouting chamber, 121-First closed end, 122-Side grouting hole, 123-Anti-backflow sleeve valve, 13-Third grouting chamber, 131-Second closed end, 132-Grouting outlet short pipe, 2-Inner core tube, 21-Drainage control valve, 22-Pressure gauge, 3-Longitudinal partition, 4-Anchor head, 41-One-way pressure opening valve, 42-One-way drainage valve, 5-Three-channel rotary distribution joint, 51-First grouting interface, 52-Second grouting interface, 53-Third grouting interface, 54-Stator part, 55-Rotor part, 6-Grouting stop plug, 7-Pan plate, 8-Locking nut, 100-Drill hole wall. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to specific embodiments. However, it should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0037] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of this utility model is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the utility model solution or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on this utility model.

[0038] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0039] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0040] Furthermore, in the description of the embodiments of this utility model, "several", "multiple", and "several" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0041] Furthermore, in the description of the technical solution of this utility model, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "equipped with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0042] Example 1 This embodiment provides a gradient viscosity layered anchor bolt for drainage and grouting coordinated control in underground engineering, mainly used for underground engineering support under high water pressure and complex geological conditions such as water-rich fault fracture zones, deep water tunnels, and vertical shafts.

[0043] like Figures 1-6 As shown in the figure, the gradient viscosity layered anchor bolt for drainage and grouting coordinated control in underground engineering provided in this embodiment includes: The outer casing 1 is preferably made of seamless steel pipe, with an outer diameter of 25~32mm, a wall thickness of 5~6mm, and an inner diameter of 15~22mm. The total length of the outer casing 1 can be flexibly configured according to the actual drilling depth on site, for example, it can be 3.0m, 4.0m or 5.0m.

[0044] The inner core tube 2 is coaxially inserted inside the outer tube 1, and the top end of the inner core tube 2 is provided with a drainage outlet.

[0045] Specifically, the outer diameter of the inner core tube 2 can be 8~10mm, and the wall thickness can be 1~2mm. Its length is slightly longer than that of the outer sleeve tube 1. By inserting the inner core tube 2 through the axis of the outer sleeve tube 1, an independent drainage channel is constructed at the central axis of the anchor rod.

[0046] Multiple longitudinal baffles 3 are disposed in the annular space between the inner wall of the outer sleeve 1 and the outer wall of the inner core tube 2. The longitudinal baffles 3 extend along the axial direction of the outer sleeve 1. Their inner side is sealed and fixed to the outer wall of the inner core tube 2, and their outer side is sealed and fixed to the inner wall of the outer sleeve 1, thereby ensuring that each separated space has good fluid sealing performance and dividing the annular space into multiple non-interconnected grouting chambers.

[0047] In order to achieve precise stratified grouting of slurries of different depths and different viscosities, the top of the outer casing 1 is provided with grouting interfaces that are independently connected to each grouting chamber. The grout outlet positions of each grouting chamber are staggered along the axial direction of the outer casing 1.

[0048] like Figure 1 As shown, the anchor head 4 is fixedly connected to the bottom end of the outer sleeve 1. The anchor head 4 can be conical to facilitate the smooth insertion of the anchor rod into the bottom of the borehole. Specifically, the anchor head 4 can be sealed and fixed to the end of the outer sleeve 1 by welding or threading. The anchor head 4 is provided with a drainage hole and a grout outlet. The drainage hole is sealed and connected to the bottom end of the inner core tube 2, allowing fissure water at the bottom of the borehole to enter the drainage channel constructed by the inner core tube 2 through the anchor head 4. The grout outlet is sealed and connected to the only grouting chamber among the multiple grouting chambers that extends to the bottom end of the outer sleeve 1. The diameter of the grout outlet can be 6mm.

[0049] Furthermore, such as Figure 2 As shown, the number of longitudinal partitions 3 is preferably three, the thickness of the longitudinal partitions 3 is preferably 2mm, and the three longitudinal partitions 3 are arranged circumferentially (preferably at equal 120° intervals) in the annular space, dividing the annular space into a first grouting chamber 11, a second grouting chamber 12 and a third grouting chamber 13.

[0050] Specifically, in this embodiment, the first grouting chamber 11 is configured to deliver a low-viscosity, slow-setting grout, so that its good fluidity allows it to be deeply injected and penetrate into the micro-fractures of the surrounding rock at the bottom of the borehole, achieving deep reinforcement. This type of grout can fully penetrate and diffuse along the micro-fractures of the surrounding rock to the deeper parts of the rock mass under grouting pressure, with a diffusion radius of 0.8~1.5m, an initial setting time of not less than 30 minutes, and a grouting pressure of 0.5~1.2MPa. This re-cements the loose and broken surrounding rock at the bottom of the borehole into a whole, forming a deep anchor body.

[0051] The second grouting chamber 12 is configured to deliver conventional grout of medium viscosity, primarily for fully filling the annular gap between the middle section of the anchor bolt and the borehole wall 100. This type of grout has moderate fluidity, an initial setting time of 15-30 minutes, and a grouting pressure of 0.3-0.8 MPa.

[0052] The third grouting chamber 13 is used to transport high-viscosity, fast-setting grout. Its purpose is to quickly squeeze out, accumulate, and solidify at the borehole opening, thereby rapidly forming a reliable physical seal and preventing grout leakage during subsequent medium-deep high-pressure grouting. This type of grout has a short gel time and high early strength, with a grouting pressure of 0.5~1.0MPa and a gel time of 1~3min. The solidified seal tightly adheres to the borehole opening section between the grout stop plug 6 and the second sealing end 131, tightly sealing the borehole opening and preventing grout backflow during subsequent deep grouting.

[0053] Furthermore, to facilitate quick identification of grouting chambers during on-site construction, the words "deep," "middle," and "shallow" can be engraved on the outer wall of the top of the outer casing 1, corresponding to the first, second, and third grouting chambers.

[0054] This structural design, through the explicit placement of three longitudinal partitions 3, creates three independent grouting chambers, precisely matching the three-section support requirements of underground engineering grouting construction: "deep penetration at the bottom of the borehole, transitional filling in the middle, and rapid sealing at the borehole opening." This structure allows construction personnel to inject grouts of different viscosities and solidification properties (low, medium, and high) into the first, second, and third chambers respectively. This ensures that the low-viscosity slurry can penetrate deep into the micro-cracks at the bottom of the borehole to enhance deep anchoring force, while the high-viscosity, fast-setting slurry can quickly seal the borehole opening to prevent grout leakage. This effectively solves the problem that traditional single-channel anchor bolts, which can only use grout of the same viscosity, cannot simultaneously achieve deep reinforcement and borehole sealing.

[0055] Furthermore, the first grouting chamber 11 has the largest axial extension length, extending from the top end of the outer sleeve 1 to the bottom end of the outer sleeve 1. The bottom end of the first grouting chamber 11 is sealed and connected to the grout outlet opened inside the anchor head 4.

[0056] To achieve precise control of the grout flow direction, a one-way pressure valve 41, commonly used in industrial production, is installed at the grout outlet of the anchor head 4. This one-way pressure valve 41 is configured to automatically open when the pressure of the low-viscosity grout in the first grouting chamber 11 reaches a preset threshold (e.g., 0.3~0.5MPa), allowing the grout to be sprayed towards the bottom of the hole; while in the non-grouting state, the valve is in a closed state, which can effectively prevent high-pressure mud or groundwater at the bottom of the hole from back-invading into the chamber and causing pipeline blockage.

[0057] The anchor head 4 is equipped with a one-way drain valve 42, which is commonly used in industrial production. One end of the one-way drain valve 42 is sealed to the bottom end of the inner core tube 2, and the other end leads to the external borehole. This one-way drain valve 42 only allows fissure water at the bottom of the borehole to flow into the inner core tube 2 in one direction.

[0058] With this structural design, the first grouting chamber 11 runs through the entire length of the outer casing 1 and directly connects to the grout outlet of the anchor head 4, ensuring that the low-viscosity, high-permeability grout can be accurately delivered to the deepest part of the borehole and directly act on the bottom section, thereby achieving large-scale penetration and cementation of the loose and fractured surrounding rock at the bottom of the borehole. The one-way pressure opening valve 41 at the grout outlet provides reliable backflow prevention protection. This valve only opens to discharge grout when the preset grouting pressure is reached. Once grouting stops or the pressure inside the borehole fluctuates, the valve can automatically close, effectively blocking the backflow of high-pressure groundwater or mud and sand from the water-rich strata into the first grouting chamber 11, and avoiding blockage of the grouting pipeline. The one-way drainage valve 42 configured at the drainage hole ensures the smooth flow of drainage channels, ensuring that the surrounding rock fissure water can only flow into the inner core pipe 2 and be discharged outwards in one direction.

[0059] Furthermore, such as Figure 1 , Figure 3 As shown, the bottom end of the second grouting chamber 12 is provided with a first closed end 121, and the distance from the first closed end 121 to the anchor head 4 is one-third of the total length of the outer sleeve 1. Specifically, the first closed end 121 can be a fan-shaped metal sheet with a thickness of 3mm, welded between the inner wall of the outer sleeve 1 and the outer wall of the inner core tube 2.

[0060] By adopting this structural design, the first closed end 121 located one-third of the length of the anchor head 4 in the second grouting chamber 12 effectively cuts off the path for the grout to continue flowing downward in the second grouting chamber 12, forcing it to be squeezed outward for filling only in the designated middle section; at the same time, this structure forms a reliable physical isolation in the axial direction, preventing cross-contamination between the middle grout and the low-viscosity grout in the deep first chamber at the bottom of the hole.

[0061] Furthermore, such as Figure 1As shown, since the bottom end of the second grouting chamber 12 has been blocked and sealed by the first closed end 121, in order to facilitate the smooth discharge of grout, several lateral grouting holes 122 are provided on the side wall of the outer casing 1 corresponding to the second grouting chamber 12. These lateral grouting holes 122 convert the grout from axial flow to radial discharge, so that the conventional grout with medium viscosity can be squeezed out evenly in all directions, thereby fully and densely filling the annular gap between the anchor rod body and the borehole wall 100 in the middle section area.

[0062] Specifically, multiple sets of lateral grouting holes 122 can be evenly opened along the axial direction at a spacing of 200mm. Each set of lateral grouting holes 122 has 3 to 4 holes evenly opened in the circumferential direction, with a hole diameter of 3 to 4mm.

[0063] Furthermore, an anti-backflow sleeve valve 123 is fitted onto the outer circumference of the outer sleeve 1, and the anti-backflow sleeve valve 123 completely covers all the lateral grouting holes 122. The anti-backflow sleeve valve 123 is preferably made of highly elastic rubber. During actual grouting operations, when the grouting pressure in the second grouting chamber 12 continuously rises until it overcomes the initial elastic clamping force of the anti-backflow sleeve valve 123, the anti-backflow sleeve valve 123 expands outward under pressure, and the grout flows out from the lateral grouting holes 122. When grouting stops, or when the groundwater pressure or mud pressure in the external environment is greater than the pressure inside the pipe, the anti-backflow sleeve valve 123 rebounds quickly due to its own elasticity, tightly wraps around the outer wall of the outer sleeve 1 again, and completely seals the lateral grouting holes 122.

[0064] This structural design, by opening lateral grouting holes 122 on the sidewall of the second grouting chamber 12, alters the flow direction of the grout, achieving radial diffusion of the grout from the middle section to the periphery. This facilitates better filling of the annular gap between the rod and the borehole wall 100. Simultaneously, an anti-backflow sleeve valve 123 is fitted over the grouting hole on the outside. Utilizing the compressive deformation characteristics of elastic rubber, the anti-backflow sleeve valve 123 is opened to allow grout to flow out when grouting pressure is applied. When grouting stops or external water pressure is excessive, the anti-backflow sleeve valve 123 quickly rebounds due to its elasticity and tightly seals the grouting hole against the pipe wall, achieving unidirectional radial grout discharge and effectively preventing backflow of external high-pressure mud or groundwater. In this embodiment, the anti-backflow sleeve valve 123 can be a sleeve valve commonly used in industrial production.

[0065] Furthermore, such as Figure 1 , Figure 4As shown, the bottom end of the third grouting chamber 13 is provided with a second closed end 131, and the distance between the second closed end 131 and the top end of the outer casing 1 is 0.5m to 1.0m. The side wall of the third grouting chamber 13 is connected to a grout outlet short pipe 132, and the diameter of the grout outlet short pipe 132 is larger than the diameter of the side grouting hole 122. Preferably, the diameter of the grout outlet short pipe 132 can be 8 to 10 mm. The grout outlet direction of the grout outlet short pipe 132 can be perpendicular to the axis of the rod and toward the borehole wall 100.

[0066] With this structural design, by setting a second closed end 131 at a distance of 0.5~1.0m from the top of the outer casing 1, the third grouting chamber 13 is precisely defined in physical space to serve only the "shallow sealing section of the orifice". The grout outlet short pipe 132 connected to its side wall provides a larger grout outlet cross section than the lateral grouting hole 122, ensuring that the thick grout can be smoothly extruded and quickly accumulate and solidify in the circumferential space of the orifice to form a reliable seal.

[0067] Furthermore, such as Figure 5 As shown, the top of the inner core tube 2 extends approximately 30mm beyond the top of the outer sleeve tube 1. A pressure gauge 22 and a drainage control valve 21 (two-way ball valve), commonly used in industrial production, are sequentially connected to the drainage outlet of the inner core tube 2. This structural design, by integrating the drainage control valve 21 and pressure gauge 22 at the drainage channel outlet, endows the anchor bolt with the ability to actively sense and regulate the hydrological environment within the borehole. The pressure gauge 22 can provide real-time and intuitive feedback on the dynamic changes in the fissure water pressure at the bottom of the borehole, providing accurate data support for setting the grouting timing and pressure. The drainage control valve 21 allows operators to precisely control the opening and closing of the drainage channel and the flow rate based on the readings, improving the flexibility and scientific nature of the grouting process.

[0068] Furthermore, such as Figure 1 , Figure 5 As shown, the top end of the outer sleeve 1 is equipped with a three-channel rotary distribution joint 5 (also called a three-channel rotary joint or multi-channel rotary joint), which is commonly used in industrial production. The three-channel rotary distribution joint 5 is configured to selectively connect the external grout supply pipeline to any one of the first grouting chamber 11, the second grouting chamber 12, or the third grouting chamber 13 through rotation. Specifically, the outer diameter of the three-channel rotary distribution joint 5 is the same as that of the outer sleeve 1, and it includes a stator part 54 and a rotor part 55 that rotates relative to the stator part 54. The stator part 54 is fixedly connected to the top end of the outer sleeve 1, and its interior has internal flow channels that communicate with the first grouting chamber 11, the second grouting chamber 12, and the third grouting chamber 13 respectively. The rotor part 55 is provided with a first grouting interface 51, a second grouting interface 52, and a third grouting interface 53, all of which are quick-connect interfaces.

[0069] In actual use, the operator rotates the rotor 55 manually or with auxiliary tools. The internal rotating ring structure allows the external grout supply pipeline to selectively align with the flow channel within the stator 54 through the corresponding grouting interface, thereby achieving precise communication with the target grouting chambers (first grouting chamber 11, second grouting chamber 12, and third grouting chamber 13). Furthermore, the three-channel rotary distribution joint 5 has a through-hole at its central axis, through which the inner core tube 2 extends outward.

[0070] This structural design, with a three-channel rotary distribution joint 5 at the top of the outer casing 1, greatly simplifies the on-site construction process for multi-chamber gradient grouting. Operators can use the rotary joint to sequentially align a single external grout supply pipe with any of the three interfaces, achieving independent grouting switching between the three chambers through rotation, reducing the need for repeated pipe disconnection and reconnection.

[0071] Furthermore, such as Figure 1 As shown, the gradient viscosity layered anchor bolt for drainage and grouting coordinated control in underground engineering provided in this embodiment also includes a grout stop plug 6, which is sleeved on the outer circumferential surface of the outer sleeve 1 near the borehole opening. Specifically, the grout stop plug 6 is preferably made of elastic rubber (e.g., nitrile rubber) or compressible soft material with good deformation capacity and corrosion resistance, and its outer diameter is slightly larger than the borehole diameter, or it can undergo radial expansion when subjected to axial compression.

[0072] With this structural design, a physical sealing barrier is initially constructed at the borehole opening by fitting a grout stopper 6 around the outer circumference of the outer sleeve 1 near the borehole opening. This grout stopper 6 effectively seals the annular gap between the anchor rod and the borehole wall 100, preventing a large amount of grout from overflowing directly from the borehole opening during the initial grouting stage.

[0073] Furthermore, such as Figure 1 As shown in the figure, the gradient viscosity layered anchor bolt for drainage and grouting coordinated control in underground engineering provided in this embodiment also includes a pad 7 and a locking nut 8. The outer periphery of the top end of the outer sleeve 1 is machined with matching mechanical threads. The pad 7 is fitted onto the outer sleeve 1, and the locking nut 8 is screwed into the threads and abuts against the outside of the pad 7. In this embodiment, the pad 7 can be specifically made of Q235 steel plate, stamped with dimensions of 150mm × 150mm × 8mm. A circular hole is opened in the center for the outer sleeve 1 to pass through.

[0074] By adopting this structural configuration, and by adding a pad 7 and a locking nut 8 to the tail end of the anchor bolt, a mechanical fastening assembly can be installed. On the one hand, prestress can be applied to the anchor bolt after the grouting operation is completed or after consolidation. The fastening load of the nut can be evenly transferred and diffused to the rock surface at the borehole opening through the pad 7, thereby providing active support resistance to the surrounding rock surface and effectively suppressing the initial loosening and deformation of the surrounding rock. On the other hand, the axial thrust generated by tightening the locking nut 8 at the beginning of construction can force the pad 7 to press the grout stop plug 6 at the borehole opening inward, causing the grout stop plug 6 to expand radially under pressure and stick tightly to the borehole wall 100, further enhancing the tightness and reliability of the initial physical seal at the borehole opening.

[0075] The gradient viscosity layered anchor bolt for drainage and grouting coordinated control in underground engineering provided in this embodiment, through the inner core tube 2 set coaxially and the drainage hole at the bottom of the anchor head 4, constructs an independent drainage channel inside the anchor bolt, thereby realizing active drainage and pressure reduction in water-rich strata, effectively avoiding the defects of grout being diluted and dispersed by high-pressure fracture water in traditional grouting process, and ensuring the anchoring quality in complex geological environments. Meanwhile, the annular space between the inner and outer pipes is physically divided into multiple non-interconnected grouting chambers by the longitudinal partition 3, and the grout outlet positions of each chamber are staggered along the axial direction. Without relying on easily failed sealing components such as external annular grout plugs, grouts of different viscosities and different setting times can be accurately delivered to sections of different depths through their own independent channels, realizing the coordinated operation of drainage and gradient viscosity stratified grouting.

[0076] Example 2 This embodiment illustrates the working mode of the gradient viscosity layered anchor bolt for drainage and grouting coordinated control in underground engineering provided in Embodiment 1: Mode 1: Drainage first, grouting later This method is mainly suitable for medium-water-rich formations where the hydrostatic pressure at the bottom of the borehole is below 0.5 MPa and the recharge rate of fissure water in the surrounding rock is slow. The specific operating steps are as follows: After the anchor bolt is lowered into the borehole at an inclined angle and initially secured, the drainage control valve 21 at the top of the anchor bolt is manually opened. Under the combined action of gravity and borehole pressure, fissure water in the surrounding rock at the bottom of the borehole enters the inner core tube 2 through the one-way drainage valve 42 and flows out of the borehole by gravity. During this process, the construction personnel monitor the drop in water pressure at the bottom of the borehole in real time using the pressure gauge 22.

[0077] Continuously monitor the reading of pressure gauge 22. When the reading drops below 0.05 MPa, or the drainage volume at the drain outlet decreases significantly, it is determined that the bottom of the hole has reached a suitable pressure reduction state for grouting. At this time, close the drain control valve 21.

[0078] The external grout supply pipeline is connected to the rotor section 55 of the three-channel rotary distribution joint 5. Based on the "deep," "medium," and "shallow" markings engraved on the outer wall of the outer sleeve 1, the rotor section 55 is aligned with the corresponding distribution channels. Grout of different viscosities is injected into the three independent chambers, achieving a step-by-step operation of "draining and depressurizing first, then gradient grouting."

[0079] Mode 2: Simultaneous drainage and grouting This method is mainly suitable for high-pressure, high-inflow formations where the hydrostatic pressure at the bottom of the borehole is not less than 0.5 MPa and drainage alone cannot effectively reduce the local water pressure, or for fractured, highly permeable formations. The specific operating steps are as follows: After the anchor bolt is lowered into the predetermined position, the top drainage control valve 21 is opened and the three-channel rotary distribution joint 5 is rotated.

[0080] Construction workers read the real-time dynamic water pressure using pressure gauge 22. During the grouting process, the output pressure of the grouting pump is adjusted in real time according to the reading of pressure gauge 22 to ensure that the grouting pressure is always higher than the real-time water pressure. The drainage channel continuously drains water to reduce the local water pressure, while the grouting channel is simultaneously injected with grout. Driven by the pressure difference, the grout permeates into the surrounding rock fissures in a positive direction.

[0081] When the grouting volume reaches the design standard, or when grout is observed at the drainage outlet, stop the grouting pump. At this time, keep the drainage control valve 21 running for 5-10 seconds before closing it, thus achieving synchronous operation of "draining and grouting simultaneously, with dynamic balance".

[0082] like Figure 6 The diagram shows the effect of surrounding rock reinforcement after grouting using the gradient viscosity layered anchor bolt for drainage and grouting coordinated control in underground engineering, as provided in Example 1. After grouting, a grout solidified body with gradient physical properties from the bottom to the opening is formed inside the borehole wall 100, as shown below: Deep anchoring section: In the deep region near the bottom of the hole, the low-viscosity, slow-setting grout injected through the first grouting chamber 11, with its excellent fluidity, is ejected through the grout outlet of the anchor head 4, fully penetrating and filling the micro-fractures deep within the surrounding rock, forming a large-scale deep low-viscosity grout diffusion zone. This effective diffusion ensures a tight grip between the anchor root and the deep strata, significantly improving the anchoring force.

[0083] Mid-section filling section: In the middle region of the anchor bolt, medium-viscosity conventional grout injected through the second grouting chamber 12 is radially extruded through the lateral grouting hole 122 and evenly fills the annular gap between the outer sleeve 1 and the borehole wall 100, forming a continuous and full mid-section grout filling body.

[0084] Shallow sealing section: In the area near the orifice, the high-viscosity fast-setting grout injected through the third grouting chamber 13 solidifies rapidly in the orifice section under the blocking effect of the grout stop plug 6, forming a high-strength orifice fast-setting seal.

[0085] The gradient viscosity layered anchor bolt provided in this embodiment for coordinated control of drainage and grouting in underground engineering features an independent drainage channel within the inner core tube 2, enabling gravity-fed drainage. For moderately water-rich strata, a "drainage first, grouting later" approach effectively reduces the water content of the surrounding rock. For high-pressure, high-inflow strata, a "drainage while grouting" approach is used, adjusting the grouting pressure to exceed the real-time water pressure to achieve dynamic balanced grouting, preventing the grout from being diluted or washed away by the high-pressure water flow.

[0086] The innovative "one rod, three chambers" design enables precise grouting with gradient viscosity: Three longitudinal baffles divide the annular space into three independent and unconnected grouting chambers, allowing for the separate and independent injection of grouts of different viscosities (low, medium, and high). This structure simultaneously meets the triple requirements of deep micro-fracture penetration at the bottom of the borehole, full circumferential filling in the middle, and rapid flow obstruction and sealing at the borehole opening on the same anchor rod, effectively resolving the engineering contradiction of traditional single-viscosity grouts where penetration and sealing are mutually exclusive.

[0087] The first grouting chamber 11 is equipped with a one-way pressure opening valve 41 at its end to prevent backflow of deep high-pressure groundwater; the second grouting chamber 12 has a lateral grouting hole 122 that works with an elastic anti-backflow sleeve valve 123 to achieve radial extrusion grout discharge and utilize elastic anti-backflow; the third grouting chamber 13 uses a large-diameter short pipe to adapt to the physical characteristics of high-viscosity slurry with poor fluidity and easy blockage, ensuring smooth grout discharge.

[0088] This device relies on the internal longitudinal partition 3 and the closed end to achieve physical space separation, and there are no mechanical moving parts inside the rod. The drainage system relies entirely on gravity flow and manual gate valve control, while the grouting system is switched purely mechanically through the top three-channel rotary distribution joint 5, without relying on external energy.

[0089] Because the three grouting chambers are independent of each other and the grout outlets are staggered in the axial direction, the construction personnel can flexibly adjust the grouting strategy according to the real-time water conditions on site (for example, freely choosing to seal the borehole opening first or anchor the bottom of the borehole first). In addition, in strata with good surrounding rock integrity, it is even possible to use only the first grouting chamber 11 for conventional single-liquid grouting, with the remaining chambers serving as backup channels, thus providing a high degree of construction freedom.

[0090] Through layered control, the amount of high-cost, high-viscosity, fast-setting grout used for orifice sealing is strictly limited to 5% to 10% of the total grouting volume in the entire borehole; while lower-cost ultrafine cement grout or ordinary cement grout can be used for deep, large-volume anchoring and penetration sections. This effectively avoids the material waste and poor deep diffusion effect caused by blindly using high-viscosity grout throughout the borehole in traditional grouting processes to prevent grout leakage.

[0091] The gradient viscosity layered anchor bolt for drainage and grouting coordinated control in underground engineering provided in this embodiment is not only suitable for conventional dry or slightly wet strata support, but also for extremely harsh working conditions such as medium water-rich strata and high-pressure large-inrush strata. It basically covers the adverse geological scenarios faced by various underground space engineering projects such as traffic tunnels, mine roadways, and underground water conservancy tunnels.

[0092] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A gradient viscosity layered anchor bolt for coordinated control of drainage and grouting in underground engineering, characterized in that, include: Outer tube (1); The inner core tube (2) is coaxially inserted inside the outer tube (1), and the top end of the inner core tube (2) is provided with a drain outlet; Multiple longitudinal partitions (3) are disposed in the annular space between the inner wall of the outer sleeve (1) and the outer wall of the inner core tube (2). The longitudinal partitions (3) extend along the axial direction of the outer sleeve (1) and divide the annular space into multiple non-communicating grouting chambers. The top end of the outer sleeve (1) is provided with a grouting interface that is independently connected to each of the grouting chambers, and the grout outlet positions corresponding to each of the grouting chambers are staggered along the axial direction of the outer sleeve (1). An anchor head (4) is fixedly connected to the bottom end of the outer sleeve (1). The anchor head (4) is provided with a drainage hole that communicates with the bottom end of the inner core tube (2) and a grout outlet that communicates with the grouting chambers of the plurality of grouting chambers that extend to the bottom end of the outer sleeve (1).

2. The gradient viscosity layered anchor bolt for coordinated control of drainage and grouting in underground engineering according to claim 1, characterized in that, The number of longitudinal partitions (3) is three, and the three longitudinal partitions (3) are arranged circumferentially in the annular space to divide the annular space into a first grouting chamber (11), a second grouting chamber (12) and a third grouting chamber (13).

3. The gradient viscosity layered anchor bolt for coordinated control of drainage and grouting in underground engineering according to claim 2, characterized in that, The first grouting chamber (11) extends from the top end of the outer sleeve (1) to the bottom end of the outer sleeve (1), and the bottom end of the first grouting chamber (11) is connected to the grout outlet on the anchor head (4); a one-way pressure opening valve (41) is provided at the grout outlet of the anchor head (4); a one-way drainage valve (42) is provided at the drainage hole on the anchor head (4).

4. A gradient viscosity layered anchor bolt for coordinated control of drainage and grouting in underground engineering according to claim 2, characterized in that, The bottom end of the second grouting chamber (12) is provided with a first closed end (121), and the distance of the first closed end (121) from the anchor head (4) is one-third of the total length of the outer sleeve (1).

5. A gradient viscosity layered anchor bolt for coordinated control of drainage and grouting in underground engineering according to claim 4, characterized in that, The second grouting chamber (12) has several lateral grouting holes (122) on its side wall, and the outer sleeve (1) is fitted with an anti-backflow sleeve valve (123) covering the lateral grouting holes (122).

6. A gradient viscosity layered anchor bolt for coordinated control of drainage and grouting in underground engineering according to claim 5, characterized in that, The bottom end of the third grouting chamber (13) is provided with a second closed end (131), and the distance between the second closed end (131) and the top end of the outer sleeve (1) is 0.5m to 1.0m; the side wall of the third grouting chamber (13) is connected to a grout outlet short pipe (132), and the diameter of the grout outlet short pipe (132) is larger than the diameter of the lateral grouting hole (122).

7. A gradient viscosity layered anchor bolt for coordinated control of drainage and grouting in underground engineering according to claim 1, characterized in that, The drain outlet of the inner core tube (2) is connected to a drain control valve (21) and a pressure gauge (22).

8. A gradient viscosity layered anchor bolt for coordinated control of drainage and grouting in underground engineering according to claim 2, characterized in that, The top end of the outer casing (1) is equipped with a three-channel rotary distribution joint (5), which is configured to allow the external grout supply pipeline to selectively connect to any one of the first grouting chamber (11), the second grouting chamber (12), or the third grouting chamber (13) by rotating.

9. A gradient viscosity layered anchor bolt for coordinated control of drainage and grouting in underground engineering according to claim 1, characterized in that, It also includes a grout stopper (6), which is fitted onto the outer circumferential surface of the outer sleeve (1) near the orifice.

10. A gradient viscosity layered anchor bolt for coordinated control of drainage and grouting in underground engineering according to claim 9, characterized in that, It also includes a pad (7) and a locking nut (8). The outer circumference of the top end of the outer tube (1) is provided with threads. The pad (7) is sleeved on the outer tube (1). The locking nut (8) is screwed into the threads and abuts against the outside of the pad (7).

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