A sleeve hydraulic expansion type grouting anchor rod and method

Abstract

The application provides a sleeve hydraulic expansion type grouting anchor rod and method, and belongs to the technical field of grouting anchor rods. The device comprises a connecting rod, a pad, a grouting pipe, an expansion shell and a cutting rod. The grouting pipe is arranged in the connecting rod, the end part is connected with the expansion shell through a connecting sleeve, the expansion shell is provided with an axially movable extrusion block, the grouting pipe is provided with a drainage block with a sharp end, a gas separation film with a radial breaking groove is arranged between the grouting head and the grouting pipe, the end part of the connecting rod is selectively provided with a first end cover with a water inlet or a second end cover with a grouting inlet and a drainage inlet, thereby forming independent water injection cavities and grouting cavities. The fixing method comprises the steps of drilling hole pretreatment, anchor rod installation, hydraulic expansion, wastewater discharge, grouting filling and sealing pressure maintaining. The linkage of the extrusion block and the drainage block realizes the temporary communication and exhaust of the water injection cavities and the grouting cavities in the hydraulic expansion stage. In the grouting stage, the drainage block pierces the gas separation film and seals and separates the two cavities, thereby achieving dynamic isolation of the hydraulic expansion and the grouting.

Description

Technical Field

[0001] This invention relates to the field of grouting anchor technology, and more specifically, to a sleeve-type hydraulic expansion grouting anchor and its method. Background Technology

[0002] In fields such as mining, tunnel excavation, and rock and soil slope reinforcement, grouting anchors are often used to control the stability of surrounding rock. For example, in the excavation of underground coal mine roadways, in order to prevent the collapse of the roof, floor, and side rock masses and ensure the safety of the excavation operation, it is often necessary to reinforce the fractured surrounding rock in advance. At this time, a sleeve-type hydraulic expansion grouting anchor and method are needed to achieve dual reinforcement of the surrounding rock by mechanical anchoring and grout filling, which facilitates the improvement of the integrity and bearing capacity of the surrounding rock.

[0003] However, traditional hydraulic grouting anchors cannot simultaneously address the dynamic isolation between hydraulic expansion pre-anchoring and grouting. This leads to air blockage in the grouting cavity during the grouting process because air cannot be completely expelled from the borehole. Consequently, the grout may not be properly filled. Furthermore, the poor sealing performance of the grout plug can easily cause grout leakage during grouting, making it difficult to maintain grouting pressure. This can result in insufficient filling of surrounding rock fissures, which not only affects the bond strength between the anchor and the surrounding rock, leading to anchoring failure, but also increases construction costs and time due to secondary grouting, ultimately threatening project safety. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a sleeve-type hydraulic expansion grouting anchor bolt and method, which solves the technical problem in the prior art where traditional devices cannot achieve dynamic isolation between hydraulic expansion pre-anchoring and grouting, and the venting and sealing coordination is poor, leading to insufficient grouting.

[0005] The purpose and effectiveness of the sleeve-type hydraulic expansion grouting anchor bolt and method of the present invention are achieved by the following specific technical means: This invention provides a sleeve-type hydraulic expansion grouting anchor bolt and its method. A sleeve-type hydraulic expansion grouting anchor bolt includes a connecting rod and a pad. One end of the connecting rod is located inside a drilled hole. The pad has a fastening nut on the side away from the drilled hole and a grout stopper on the other side. Both the fastening nut and the grout stopper are sleeved on the connecting rod. A grouting pipe passes through the connecting rod. An expansion shell is provided at the end of the connecting rod located in the drilled hole. The expansion shell is connected to the connecting rod through a connecting sleeve. An extrusion block is provided at the end of the expansion shell near the connecting sleeve. The extrusion block is sleeved on the grouting pipe, and the expansion shell has a grouting head at one end away from the connecting sleeve. One end of the grouting pipe passes through the expansion shell and is connected to the grouting head. A drainage block is provided at the end of the grouting pipe away from the grouting head; A cutting rod is installed at the end of the grouting head away from the expansion shell, and the cutting rod is connected to the borehole by an anchoring agent; The connecting rod may be provided with a first end cap or a second end cap at the end away from the borehole. The first end cap has a water injection port, and the second end cap has a grout injection port. A grouting cavity is formed inside the grouting pipe, and a water injection cavity is formed between the grouting pipe, the expansion shell, and the connecting rod.

[0006] In a preferred embodiment, the expansion shell includes an expansion section and two sets of connecting sections, the two sets of connecting sections being located at both ends of the expansion section, and the connecting sections being connected to the expansion section via a frustum-shaped transition section; The expansion section includes multiple sets of spiral lobes, which are connected by spiral elastic ribs. The spiral lobes are made of alloy steel, and the spiral elastic ribs are made of spring steel. The two sets of connecting sections are respectively provided with a first receiving groove and a second receiving groove for accommodating the extruded block. Both the connecting section and the frustum transition section are made of low alloy steel. The two sets of connecting sections are respectively threaded to the connecting sleeve and the grouting head.

[0007] As a preferred embodiment, a guide rib is formed on the expansion section and the frustum transition section, and a second guide groove is provided on the outer wall of the extrusion block, with the guide rib and the second guide groove being slidably connected; The extrusion block is made of alloy structural steel and is covered with a rubber layer. The extrusion block has multiple sets of ventilation holes, and each ventilation hole is equipped with a one-way valve.

[0008] As a preferred embodiment, the grouting head is provided with a grouting groove and a plurality of radially distributed grouting holes inside, and a third receiving groove is provided inside the grouting head for accommodating the tip of the drainage block.

[0009] As a preferred embodiment, an air-barrier membrane is provided at the connection between the grouting head and the grouting pipe, the air-barrier membrane comprising a substrate layer and a metal barrier layer arranged sequentially along the grouting direction; The substrate layer is a polypropylene film, the metal barrier layer is an aluminum film, and the gas barrier film has crack grooves that are radially distributed on the side of the gas barrier film near the expansion shell.

[0010] As a preferred embodiment, the drainage block is provided with a flow guiding channel, which includes a main cavity and multiple sets of radially distributed flow guiding holes. A sealing sleeve is fitted on the drainage block, and the sealing sleeve is made of nitrile rubber. The drainage block is provided with multiple sets of limiting blocks, which are located between two adjacent sets of the guide holes. The grouting pipe is provided with a limiting groove for restricting the movement of the limiting blocks. The end of the drainage block facing the grouting head is provided with a tip for piercing the air barrier membrane.

[0011] As a preferred embodiment, the grouting pipe has an vent hole at one end near the grouting head; When the drainage block moves inside the grouting pipe and the squeezing block is located in the first receiving groove: the squeezing block divides the water injection chamber into a waterless chamber and a water-containing chamber, the grouting chamber is connected to the waterless chamber through the vent hole, and the waterless chamber and the water-containing chamber are connected through the ventilation hole; The waterless cavity is located on the side of the extrusion block closer to the grouting head, and the water-containing cavity is located on the side of the extrusion block farther from the grouting head; When the drainage block is located in the third receiving groove and the squeezing block is located in the second receiving groove: the drainage block is located on the side of the vent hole, separating the water injection chamber and the grouting chamber into independent chambers, and the grouting chamber is connected to the grouting groove through the guide channel of the drainage block.

[0012] In a preferred embodiment, the water inlet is connected to the water injection cavity, and the first end cap is provided with a first plug, which is engaged in the grouting cavity; The grouting port is connected to the grouting cavity, and a drain outlet is provided on the side wall of the second end cap. The drain outlet is connected to the water injection cavity, and a second plug is provided on the second end cap. The second plug is locked in the water injection cavity.

[0013] As a preferred embodiment, the grout stopper includes a first retaining ring and a second retaining ring, which are connected by an elastic sealing ring. The elastic sealing ring contains a spring and multiple sets of vent holes. The first retaining ring has a vent groove, which contains a filter block. One end of each set of vent holes is connected to the vent groove, and the other end is connected to the drill hole. The second retaining ring is provided with multiple sets of guide posts, and the first retaining ring is provided with multiple sets of first guide grooves, wherein the guide posts are slidably connected to the first guide grooves.

[0014] A method for fixing a sleeve-type hydraulic expansion grouting anchor bolt, applied to the aforementioned sleeve-type hydraulic expansion grouting anchor bolt, includes the following steps: S1 borehole pretreatment: Drill holes in the surrounding rock with a diameter 10-15 mm larger than the outer diameter of the anchor bolt, and use high-pressure air to clean the rock cuttings and water inside the holes; Fill the bottom of the borehole with a cylindrical anchoring agent with a diameter matching the borehole and a length one-third the length of the cutting rod. A hole matching the cutting rod is reserved in the center of the anchoring agent. S2 Anchor Bolt Installation: Insert the end of the cutting rod into the pre-drilled hole for the anchoring agent, and slowly push the anchor rod until the expansion shell is fully inserted into the borehole, ensuring that the distance between the grouting head and the bottom of the borehole is greater than or equal to 50mm; At this time, the vent hole of the grout stop plug remains open, and the guide column is inserted into the first guide groove to a depth of one-quarter of the total stroke; Let it stand for 5 to 10 minutes until the anchoring agent has initially cured. When you hold the anchor rod and there is no obvious shaking, it means that the fixing is complete. Rotate the fastening nut to move the first retaining ring of the grout stop plug toward the borehole opening, so that the elastic sealing ring initially fits against the inner wall of the borehole. S3 hydraulic expansion: Install a first end cap at the end of the connecting rod to ensure that the first plug fits the grouting cavity with an interference fit; Water is injected into the injection chamber through the injection port at a pressure of 0.8-1.2 MPa. The water pressure pushes the extrusion block to move axially along the grouting pipe. The second guide groove of the extrusion block slides along the guide rib, generating circumferential rotation while advancing axially; The spiral flaps of the extrusion expansion section expand radially until they adhere to the inner wall of the borehole. The proper adhesion is determined by stabilizing the water injection pressure at 1.0 MPa. During the expansion process, the air in the waterless cavity enters the grouting cavity through the exhaust hole on the grouting pipe, and the grouting cavity obtains the initial air pressure; S4 discharges wastewater from the water injection chamber: Remove the first end cap and replace it with the second end cap; At this time, the drainage block is located at the end of the grouting pipe away from the grouting head, and the grouting chamber is connected to the waterless chamber through the vent hole; Low-pressure grout is injected into the grouting chamber through the grouting port of the second end cap. The pressure is 0.2-0.3 MPa. At the same time, the grouting pressure pushes the drainage block to move towards the grouting head, and the air in the grouting chamber enters the waterless chamber through the exhaust hole on the grouting pipe. Under air pressure, the gas in the waterless chamber pushes the one-way valve in the extrusion block to open, and the gas enters the water chamber from the waterless chamber through the one-way valve. As gas continues to flow in, the pressure inside the water chamber increases, pushing the wastewater inside the chamber out through the drain port of the second end cap; The drain outlet and the water chamber are connected by an axial channel of a connecting rod. Wastewater is continuously discharged along this channel until there is no continuous water flow at the drain outlet, which indicates that the water chamber is empty. As the drainage block moves, its tip gradually approaches the air barrier membrane; S5 grouting and filling: Continue to increase the grouting pressure to 0.5-0.6MPa, and the drainage block continues to move until the limiting block contacts the step of the limiting groove on the inner wall of the grouting pipe. At this time, the drainage block enters the third receiving groove, and the tip of the drainage block pierces the air-tight membrane, and the rupture groove cracks radially. The sealing sleeve on the drainage block fits against the inner wall of the grouting pipe, completely separating the water injection chamber from the grouting chamber; After the air-tight membrane is punctured, the grout enters the grouting groove of the grouting head through the main cavity and guide hole of the drainage block. The grout diffuses into the borehole gap through multiple sets of radial grouting holes of the grouting head. S6 Exhaust and Sealing Pressure Maintenance: During the grouting process, the residual air in the grouting cavity is discharged through the vent hole of the grout stop plug, through the vent groove, the gap between the second retaining ring and the connecting rod; When the grouting pressure rises to 1.0-2.0 MPa, the grout pressure pushes the second retaining ring of the grout stop plug closer to the first retaining ring, the elastic sealing ring is axially compressed, the spring contracts, its outer wall fits against the inner wall of the borehole, and at the same time the vent hole is closed due to the deformation of the sealing ring, thus achieving borehole sealing. Maintain this pressure for 3-5 minutes to ensure the grout is fully filled, then stop grouting; S7 anchoring complete: Remove the second end cap, install the plug, and complete the anchor bolt anchoring after the grout has solidified.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention, through the synergy of the extrusion block and the drainage block, enables the device to achieve dynamic isolation between the hydraulic expansion pre-anchoring and grouting stages, thus improving the process coordination of the device. The device can divide the water injection chamber into a waterless chamber and a water-containing chamber through the extrusion block, guiding the orderly discharge of air during the hydraulic expansion stage; during grouting, the drainage block forms an independent cavity by fitting with the grouting pipe through a sealing sleeve, preventing water and grout from mixing. This ensures both the expansion anchoring effect and the purity of the grout, improving the adaptability of the device in complex surrounding rock.

[0016] 2. When using this device, the elastic sealing ring of the grout stop plug combined with the vent hole achieves adaptive coordination of venting and sealing. This allows residual air to be discharged through the vent hole during the initial grouting stage, avoiding air resistance. When the pressure rises to 1.0–2.0 MPa, the sealing ring deforms under pressure, sealing the vent hole and achieving a reliable seal, thus improving the device's grouting pressure holding capacity. Furthermore, a filter block prevents rock debris from clogging the venting channel, reducing grouting defects and enhancing the device's engineering practicality.

[0017] 3. This invention, through the combination of the spiral petals of the expanding shell and the spiral elastic ribs, enables the device to form initial anchorage, thereby enhancing its emergency support capability. The device can use water pressure to push the extrusion block, causing the spiral petals to expand radially and engage with the borehole wall. Combined with the initial fixation of the insertion rod and anchoring agent, the device can provide anchoring force from the initial installation stage, improving its rapid response capability in fractured surrounding rock. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the assembly structure of the invention; Figure 2 This is a schematic diagram of the internal structure of the invention; Figure 3 This is a schematic diagram of the disassembled structure of the slurry stop plug of the invention; Figure 4 This is a schematic diagram of the internal structure of the slurry stopper of the invention; Figure 5 This is a partial schematic diagram of the grouting surface of the invention; Figure 6 This is a schematic cross-sectional view of the expansion shell of the invention; Figure 7 This is a schematic longitudinal section of the expansion shell of the invention; Figure 8 This is a cross-sectional schematic diagram of the internal structure tube of the extrusion block of the invention; Figure 9 This is a schematic diagram of the extrusion block of the invention; Figure 10 This is a schematic diagram of the drainage block of the invention; Figure 11 This is a schematic diagram of the internal structure of the drainage block of the invention; Figure 12 This is a schematic diagram of the structure of the first end cap of the invention; Figure 13 This is a schematic diagram of the structure of the second end cap of the invention; Figure 14 This is a schematic diagram of the internal structure of the air-barrier membrane of this invention; Figure 15 This is a flowchart of the solidification method of the invention; Figure 16 This is a schematic diagram of the structure of the spiral petals and spiral elastic ribs of the invention.

[0019] In the diagram, the correspondence between component names and their corresponding reference numerals is as follows: 11. Connecting rod; 12. Pad; 13. Tighten the nuts: 14. Stop plug; 141. First retaining ring; 142. Second retaining ring; 143. Elastic sealing ring; 144. Vent hole; 145. Vent groove; 146. Guide post; 147. First guide groove; 148. Spring; 149. Filter block; 15. Grouting pipe; 151. Vent hole; 152. Limiting groove; 16. Expansion shell; 161. Spiral petal; 162. Spiral elastic rib; 163. Connecting section; 164. Frustum transition section; 165. First receiving groove; 166. Guide rib; 167. Expansion section; 168. Second receiving groove; 17. Connecting sleeve; 18. Extrusion block; 181. Second guide groove; 182. Ventilation hole; 183. One-way valve; 19. Grouting head; 191. Grouting groove; 192. Grouting hole; 193. Third receiving groove; 21. Drainage block; 211. Main cavity; 212. Guide hole; 213. Tip; 214. Limiting block; 215. Sealing sleeve; 22. Insertion rod; 23. Anchoring agent; 24. First end cap; 241. First plug; 242. Water inlet; 25. Second end cap; 251. Second plug; 252. Drain outlet; 253. Grouting port; 26. Air barrier membrane; 261. Substrate layer; 262. Metal barrier layer; 263. Crack groove. Detailed Implementation

[0020] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the technical solutions of the present invention, but should not be used to limit the scope of protection of the present invention.

[0021] Example: Figures 1 to 16 As shown, the present invention provides a sleeve-type hydraulic expansion grouting anchor bolt, including a connecting rod 11 and a pad 12. One end of the connecting rod 11 is located inside the drill hole. The pad 12 is provided with a fastening nut 13 on the side away from the drill hole and a grout stop plug 14 on the other side. Both the fastening nut 13 and the grout stop plug 14 are sleeved on the connecting rod 11.

[0022] With this setup, when the device is fixed to the surrounding rock by the anchoring agent 23, the pad 12 can adhere to the surface of the surrounding rock by the pre-tightening force of the fastening nut 13, forming initial support; the grout stop plug 14 is located between the pad 12 and the borehole opening, which can adjust the position with the fastening nut 13 through the sleeve structure, and can also initially seal the borehole opening during subsequent grouting to prevent grout from overflowing, laying the foundation for subsequent sealing and pressure maintenance.

[0023] A grouting pipe 15 is inserted inside the connecting rod 11. An expansion shell 16 is provided at one end of the connecting rod 11 located in the borehole. The expansion shell 16 is connected to the connecting rod 11 through a connecting sleeve 17. An extrusion block 18 is provided at one end of the expansion shell 16 near the connecting sleeve 17.

[0024] With this configuration, the grouting pipe 15 serves as an independent channel through the connecting rod 11, providing a dedicated path for grout delivery; the expansion shell 16 is rigidly connected to the connecting rod 11 via the connecting sleeve 17, ensuring stable transmission of expansion force; the extrusion block 18 is fitted onto the grouting pipe 15 and can move axially along the grouting pipe 15, extruding the expansion shell 16 under water pressure, thus achieving the force transmission of "hydraulic drive-mechanical expansion" and overcoming the limitations of traditional anchor bolts that rely on a single anchoring method.

[0025] Furthermore, the connecting rod 11 is made of high-strength low-alloy steel, such as Q355 alloy steel, which serves as the main frame to bear the anchoring tension and ensure overall rigidity; the grouting pipe 15 is made of seamless steel pipe, such as 20# steel, with a smooth inner wall to reduce grout resistance, and an independent channel to avoid mutual interference with the connecting rod 11, ensuring that it does not bulge under internal pressure during grouting, while being isolated from the annular water injection cavity formed by the connecting rod 11, so that the pressure of the two cavities does not interfere with each other.

[0026] For example, the grouting pipe 15 is made of 20# seamless steel pipe with an outer diameter of 20mm and a wall thickness of 3mm, and the connecting rod 11 has an inner diameter of 25mm. The two form an annular water injection cavity with a thickness of 2.5mm, ensuring a flow rate of ≥5L / min under a water pressure of 0.8-1.2MPa to meet the expansion speed requirements. The connection between the grouting pipe 15 and the expansion shell 16 and the grouting head 19 is an M18×1.5 fine thread with a thread engagement length of ≥15mm to ensure no leakage under a pressure of 1.5MPa.

[0027] The extrusion block 18 is sleeved on the grouting pipe 15. The expansion shell 16 is provided with a grouting head 19 at the end away from the connecting sleeve 17. One end of the grouting pipe 15 passes through the expansion shell 16 and is connected to the grouting head 19.

[0028] With this configuration, the nesting relationship between the extrusion block 18 and the grouting pipe 15 ensures that the extrusion block 18 can move stably along the axial direction without obstructing the grout delivery of the grouting pipe 15. The grouting pipe 15 passes through the expansion shell 16 and connects to the grouting head 19, so that the grout can reach the grouting head 19 at the depth of the borehole and diffuse into the surrounding rock fissures through the grouting hole 192 of the grouting head 19, ensuring that the grout filling range covers the entire anchoring section.

[0029] It should be noted that the extrusion block 18 is sealed to the grouting pipe 15 by a nitrile rubber sealing ring, which is press-fitted to the outer wall of the grouting pipe 15. This is not shown in the figure and is a conventional method in this technical field, which can prevent high-pressure water in the water injection chamber from seeping into the grouting pipe 15.

[0030] A drainage block 21 is provided at the end of the grouting pipe 15 away from the grouting head 19.

[0031] With this configuration, the drainage block 21 can move along the grouting pipe 15 under the pressure of grouting, which can drain the residual water in the water injection chamber before grouting and avoid diluting the grout.

[0032] A cutting rod 22 is installed at the end of the grouting head 19 away from the expansion shell 16. The cutting rod 22 is connected to the borehole through the anchoring agent 23.

[0033] With this setup, the insertion rod 22 is inserted into the anchoring agent 23 at the bottom of the borehole. In the early stage of device installation, the initial curing of the anchoring agent 23 forms a "point anchoring", which, together with the subsequent "surface anchoring" of the expansion shell 16, forms a "point-surface combination" multi-anchoring system, improving the initial stability in the fractured surrounding rock and preventing displacement caused by deformation of the surrounding rock after the device is installed.

[0034] The end of the connecting rod 11 away from the borehole may be provided with either a first end cap 24 or a second end cap 25. The first end cap 24 has a water injection port 242, and the second end cap 25 has a grout injection port 253.

[0035] With this configuration, the water inlet 242 of the first end cap 24 is dedicated to providing a high-pressure water channel for the hydraulic expansion stage, while the grouting inlet 253 of the second end cap 25 is used to transport grout during the grouting stage. Choosing one of these configurations allows for independent switching between the "expansion-grouting" process, avoiding interference between the media (water and grout) in the two stages and ensuring that each process is specialized and stable.

[0036] A grouting cavity is formed inside the grouting pipe 15, and a water injection cavity is formed between the grouting pipe 15, the expansion shell 16, and the connecting rod 11.

[0037] With this configuration, the two chambers are physically isolated by the wall of the grouting pipe 15. The water injection chamber is used only for hydraulic expansion, and the grouting chamber is used only for conveying grout, completely avoiding the mixing of water and grout. This ensures both stable water pressure during the expansion stage and the purity and strength of the grout during the grouting stage, thus solving the functional conflict problem caused by the single chamber of the traditional device.

[0038] Specifically, the anchor bolt achieves anchoring through "component functional zoning + process progressive collaboration": with the connecting rod 11 as the core skeleton to integrate various key components, firstly relying on the insertion rod 22 and anchoring agent 23 to complete the initial positioning and fixation, then using hydraulic drive to expand the shell 16 to form mechanical interlocking, and finally using the isolation effect of the independent cavity and drainage block 21 to achieve pure slurry filling, taking into account rapid fixation, expansion and grouting throughout the process, and constructing a multi-stage, multi-level reinforcement system.

[0039] For example, when applied in the fractured surrounding rock of a coal mine roadway: In the initial stage of installation, the insertion rod 22 is inserted into the bottom anchoring agent 23 to quickly form a stable support point, preventing the anchor from tilting in the soft surrounding rock; after the hydraulic expansion is started, the extrusion block 18 pushes the spiral petals 161 to expand radially and fit against the hole wall to form a reliable temporary anchor; in the grouting stage, the drainage block 21 drains the residual water and isolates the two cavities, and the grout penetrates evenly into the surrounding rock fissures through the radial holes of the grouting head 19. The grout stop plug 14 seals under pressure, and finally the grout fully fills the borehole and surrounding rock fissures, improving the anchoring stability compared to traditional anchors and restraining the deformation of the surrounding rock in the roadway.

[0040] like Figures 1 to 7 As shown, the expansion shell 16 includes an expansion section 167 and two sets of connecting sections 163. The two sets of connecting sections 163 are located at both ends of the expansion section 167, and the connecting sections 163 and the expansion section 167 are connected by a frustum transition section 164.

[0041] With this configuration, the frustum transition section 164 can smoothly transfer the axial force transmitted by the connecting section 163 to the expansion section 167, avoiding sudden changes in force that could lead to local stress concentration, ensuring that the expansion section 167 is subjected to uniform force, and preventing breakage due to local overload.

[0042] The expansion section 167 includes multiple sets of spiral petals 161, which are connected by spiral elastic ribs 162. The spiral petals 161 are made of alloy steel, and the spiral elastic ribs 162 are made of spring steel.

[0043] With this design, the alloy steel material of the spiral petal 161 ensures rigidity and wear resistance during expansion, and can engage with the borehole wall; the spring steel material of the spiral elastic rib 162 gives the expansion section 167 good expansion capacity, which can expand radially synchronously with the extrusion block 18, and maintain continuous tension after the pressure stabilizes, avoiding shrinkage after expansion and improving the long-term effectiveness of mechanical anchoring.

[0044] Furthermore, the spiral petal 161 adopts a segmented spiral structure, such as 4-6 groups of petals. Adjacent petals are connected by spiral elastic ribs 162, and the spiral angle of the spiral petals 162 is consistent with the direction of rotation of the spiral elastic ribs 162, such as 30° right-handed. The spiral petal 161 can be made of 42CrMo alloy steel, which is quenched and tempered to enhance wear resistance and rigidity. The spiral elastic ribs 162 can be made of 60Si2Mn spring steel, which is heat-treated to give it good fatigue strength and maintain stable mechanical properties during tensile testing. When the extrusion block 18 is axially advanced, the spiral elastic ribs 162 are tensile and generate radial force, which works in conjunction with the rigid expansion of the spiral petals 161. This avoids uneven deformation caused by excessive force on a single group of petals, and the energy storage effect of the spiral elastic ribs 162 can compensate for gaps when there are slight deviations in the borehole diameter, ensuring close contact with the borehole wall.

[0045] For example, the initial diameter of the expansion section 167 spiral flap 161 is 82%–85% of the borehole diameter (e.g., 82–85 mm for a borehole diameter of 100 mm), and the maximum expansion diameter is 1–2 mm larger than the borehole diameter (i.e., 101–102 mm). Engagement with the borehole wall is achieved through an interference fit of 0.5%–2%. The number of spiral flaps 161 is adapted to the hardness of the surrounding rock. Six sets of flaps are used for fractured surrounding rock (uniaxial compressive strength ≤30MPa) to increase the contact area and disperse stress; four sets of flaps are used for medium-hard rock (30-60MPa) to balance rigidity and expansion efficiency.

[0046] The two sets of connecting sections 163 are respectively provided with a first receiving groove 165 and a second receiving groove 168 for accommodating the extrusion block 18. Both the connecting section 163 and the frustum transition section 164 are made of low alloy steel.

[0047] With this configuration, the first receiving groove 165 near the end of the connecting rod 11 provides initial installation space for the extrusion block 18, while the second receiving groove 168 away from the end of the connecting rod 11 provides a limit for the stroke end of the extrusion block 18, ensuring that it is in a stable position when not under force. The low alloy steel material (such as Q355 alloy steel) takes into account both strength and toughness, which not only meets the rigid connection requirements of the connecting section 163 with the connecting sleeve 17 and the grouting head 19, but also works with the frustum transition section 164 to buffer the impact force during expansion and avoid brittle fracture.

[0048] The two sets of connecting sections 163 are threadedly connected to the connecting sleeve 17 and the grouting head 19 respectively, and a sealing ring is provided at the connection (not shown in the figure).

[0049] This design allows for quick on-site assembly and disassembly of the threaded connection, adapting to the adjustment needs of different drilling depths; the sealing ring reliably seals the connection gap, preventing leakage of high-pressure water from the water injection chamber or grout from the grouting chamber, ensuring stable pressure, and guaranteeing expansion and grouting effects. The sealing ring can be made of nitrile rubber.

[0050] Specifically, the expansion shell 16 ensures the transmission of force during hydraulic expansion through a structural chain of "force transmission through connecting section 163 - force uniformity through frustum transition section 164 - force amplification through expansion section 167". Furthermore, through the synergy of the spiral structure and the spiral elastic rib 162, the expansion section 167 forms a mechanical engagement with the borehole wall, laying the foundation for subsequent grouting reinforcement.

[0051] like Figures 1 to 9 As shown, a guide rib 166 is formed on the expansion section 167 and the frustum transition section 164, and a second guide groove 181 is provided on the outer wall of the extrusion block 18. The guide rib 166 and the second guide groove 181 are slidably connected.

[0052] With this configuration, the cooperation between the guide rib 166 and the second guide groove 181 provides the movement trajectory for the extrusion block 18. This not only constrains the extrusion block 18 to move smoothly along the axial direction, avoiding uneven expansion, but also guides the extrusion block 18 to rotate synchronously during movement through the helical angle of the guide structure, such as 30° right-hand rotation. This makes the helical petals 161 of the expansion section 167 more evenly stressed, achieving symmetry in radial expansion and preventing local over-extrusion from causing damage to the borehole wall. The extrusion block 18 is shaped like a frustum.

[0053] The extrusion block 18 is made of alloy structural steel and is covered with a rubber layer.

[0054] With this configuration, the alloy structural steel (such as 35CrMo) has high strength and wear resistance, and can withstand the axial force and radial reaction force when driven by high-pressure water, thus avoiding its own deformation; the rubber layer (such as nitrile rubber) can avoid rigid contact between the extrusion block 18 and the expansion section 167, reduce component wear, and at the same time enhance the sealing of the contact surface between the two, preventing high-pressure water in the water injection chamber from leaking out of the gap.

[0055] Multiple sets of ventilation holes 182 are provided inside the extrusion block 18, and a one-way valve 183 is provided inside the ventilation hole 182.

[0056] With this configuration, the extrusion block 18 divides the water injection chamber into a water-containing chamber and a waterless chamber. The vent 182 provides a gas flow channel between the water-containing chamber and the waterless chamber. The one-way valve 183 is integrated, integrally formed with the extrusion block 18, i.e., the valve seat is embedded in the extrusion block 18, avoiding swaying issues. This one-way valve 183 only allows gas to flow from the waterless chamber to the water-containing chamber. It can both expel air from the waterless chamber during the hydraulic expansion stage (avoiding air resistance that hinders the movement of the extrusion block 18) and prevent residual water or slurry in the water-containing chamber from flowing back into the waterless chamber during the grouting stage, ensuring that the pressure of the two chambers does not interfere with each other.

[0057] The extrusion block 18 is engaged in the second receiving groove 168 at the end away from the connecting rod 11 through the following structure. The second receiving groove 168 forms a radial limit on the outer wall of the extrusion block 18. The rubber layer on the extrusion block 18 is initially in a slightly expanded state. The rubber layer undergoes elastic deformation under pressure, filling the gap of the conical surface and enhancing the contact friction. The high-pressure water continuously injected into the water injection chamber pushes the extrusion block 18 axially, so that the contact pressure of the conical surface increases with the increase of water pressure, further compacting the fit gap between the extrusion block 18 and the second receiving groove 168. Finally, under the synergistic effect of axial thrust, radial constraint and water pressure compaction, the extrusion block 18 is engaged in the groove and achieves stable positioning.

[0058] The reason why air pressure can push the wastewater generated in the water injection chamber after expansion to be discharged is that: during the movement of the extrusion block 18, the air in the waterless chamber flows into the water chamber in one direction through the air exchange hole 182, so that the air pressure in the water chamber increases with the continuous influx of air; when the air pressure in the water chamber exceeds the resistance of the external drainage path, such as the pressure difference between the drain outlet 252 and the outside, the air pressure will push the residual wastewater in the chamber to flow along the axial channel of the connecting rod 11 to the drain outlet 252, and finally realize the discharge of wastewater. The one-way flow characteristic of the one-way valve 183 ensures that gas can only enter the water chamber from the waterless chamber, avoids the backflow of wastewater or gas, and ensures that the air pressure continues to act on the wastewater, forming a stable discharge force.

[0059] like Figure 1 , Figure 5 As shown, the grouting head 19 has a grouting groove 191 and a plurality of radially distributed grouting holes 192 inside, and a third receiving groove 193 for accommodating the tip of the drainage block 21 is provided inside the grouting head 19.

[0060] With this configuration, the grouting groove 191 can guide the flow of grout, and the radially distributed grouting holes 192 can allow the grout to spread evenly to the surrounding rock fissures; the third receiving groove 193 can position the drainage block 21, ensuring that after the drainage block 21 is in place, the grout can smoothly enter the grouting groove 191 and flow out through the grouting holes 192 to achieve grouting.

[0061] like Figures 1 to 10 and Figure 14 As shown, an air-barrier membrane 26 is provided at the connection between the grouting head 19 and the grouting pipe 15. The air-barrier membrane 26 includes a substrate layer 261 and a metal barrier layer 262 arranged sequentially along the grouting direction.

[0062] With this configuration, the substrate layer 261 and the metal barrier layer 262 work together to form a dual barrier, which can prevent water or gas from entering the grouting cavity during the hydraulic expansion stage (to avoid contaminating the grout to be injected), and can also be disrupted during the grouting stage to allow the grout to pass through, thus achieving a controllable switch between "isolation and conduction".

[0063] The substrate layer 261 is a polypropylene film, the metal barrier layer 262 is an aluminum film, and the gas barrier membrane 26 has a rupture groove 263, which is radially distributed on the side of the gas barrier membrane 26 near the expansion shell 16.

[0064] With this configuration, the polypropylene membrane provides tough support, and the aluminum membrane enhances the barrier properties against gas and liquid. The radial rupture grooves 263 allow the gas barrier membrane 26 to crack along a preset trajectory when squeezed by the tip 213 of the drainage block 21, avoiding disorderly breakage and ensuring that a smooth channel is formed after rupture, without blocking the flow of slurry.

[0065] Specifically, the air-barrier membrane 26 plays an isolation role during the hydraulic expansion and drainage stages: the aluminum membrane blocks the gas in the grouting cavity from entering the grouting tank 191, and the polypropylene membrane enhances the overall structural strength and prevents accidental damage; when the drainage block 21 moves to the third receiving tank 193, its tip 213 squeezes the air-barrier membrane 26, and the radial rupture groove 263 guides the membrane to crack radially, forming multiple fan-shaped openings. The grout can smoothly enter the grouting tank 191 through the openings, which not only ensures strict isolation before grouting, but also realizes the conduction during grouting.

[0066] like Figures 10 to 11 As shown, a flow channel is provided on the drainage block 21. The flow channel includes a main cavity 211 and multiple sets of radially distributed flow holes 212. A sealing sleeve 215 is fitted on the drainage block 21. The sealing sleeve 215 is made of nitrile rubber.

[0067] With this configuration, the main cavity 211 serves as the main channel for grout flow, and the radial guide hole 212 can disperse and discharge the grout from the main cavity 211, ensuring that the grout enters the grouting head 19 evenly. The nitrile rubber sealing sleeve 215 can fit against the inner wall of the grouting pipe 15 to form a dynamic seal, which not only prevents gas in the water injection cavity or grout in the grouting cavity from flowing through the cavity when the drainage block 21 moves, but also maintains the seal when sliding with the drainage block 21 to avoid media leakage.

[0068] The drainage block 21 is provided with multiple sets of limiting blocks 214, which are located between two adjacent sets of guide holes 212. The grouting pipe 15 is provided with a limiting groove 152 for restricting the movement of the limiting block 214. The end of the drainage block 21 facing the grouting head 19 is provided with a tip 213 for piercing the air barrier membrane 26.

[0069] With this configuration, the limiting block 214 and the limiting groove 152 can limit the movement of the drainage block 21, preventing it from moving excessively and causing structural misalignment; the tip 213 can pierce the air barrier membrane 26 when the drainage block 21 reaches the grouting head 19, opening a channel for grout flow and preventing the air barrier membrane 26 from remaining and blocking the grouting path.

[0070] Specifically, the drainage block 21 achieves multiple functions through the integrated design of "flow guidance - sealing - limiting - membrane breaking": the flow guidance channel ensures the delivery of slurry, the sealing sleeve 215 isolates the media in the two chambers, the limiting structure controls the movement accuracy, and the tip 213 breaks the air-barrier membrane 26, ultimately ensuring that residual water is smoothly drained during the drainage stage and that the slurry flows unimpeded during the grouting stage.

[0071] like Figures 1 to 9 As shown, the grouting pipe 15 has an exhaust hole 151 at one end near the grouting head 19.

[0072] With this configuration, the vent 151 can expel residual air from the grouting cavity before grouting, preventing air stagnation from forming air resistance that hinders grout flow and ensuring that the grout can smoothly fill the grouting head 19.

[0073] When the drainage block 21 moves inside the grouting pipe 15 and the squeezing block 18 is located in the first receiving groove 165: the squeezing block 18 divides the water injection chamber into a waterless chamber and a water-containing chamber. The grouting chamber is connected to the waterless chamber through the vent hole 151, and the waterless chamber and the water-containing chamber are connected through the air exchange hole 182.

[0074] This configuration creates an air circulation path of "grouting chamber - waterless chamber - water chamber". Air in the grouting chamber enters the waterless chamber through the exhaust port 151, then flows into the water chamber through the air exchange port 182, and is finally discharged with the wastewater, thus avoiding air resistance that hinders the movement of the drainage block 21 and the extrusion block 18.

[0075] The waterless cavity is located on the side of the extrusion block 18 closer to the grouting head 19, while the water-containing cavity is located on the side of the extrusion block 18 away from the grouting head 19.

[0076] This configuration places the waterless chamber close to the vent hole 151 of the grouting chamber, shortening the gas flow path; the water-filled chamber is far from the grouting head 19, facilitating the high-pressure water to drive the extrusion block 18 from the end of the connecting rod 11, conforming to the force transmission direction and improving driving efficiency.

[0077] When the drainage block 21 is located in the third receiving groove 193 and the squeezing block 18 is located in the second receiving groove 168: the drainage block 21 is located on the side of the vent hole 151, separating the water injection chamber and the grouting chamber into independent chambers, and the grouting chamber is connected to the grouting groove 191 through the guide channel of the drainage block 21.

[0078] This design prevents the air in the water injection chamber from mixing with the grout in the grouting chamber, while allowing the grout to flow into the grouting tank 191 through the guide channel and be injected into the surrounding rock through the radial grouting hole 192, thus achieving an orderly connection between "isolation-guide-grouting".

[0079] Specifically, by dynamically separating the positions of the exhaust port 151 and the air exchange port 182 from the cavity, the device forms targeted air / liquid paths at different stages: during the drainage stage, the gas circulation channel is opened to avoid air blockage; during the grouting stage, water and grout are completely isolated to ensure the purity of the grout; and finally, through structural synergy, smooth drainage and efficient grouting are ensured.

[0080] like Figure 4 , Figure 12 , Figure 13 As shown, when the first end cap 24 is connected to the connecting rod 11, the water inlet 242 is connected to the water injection cavity, and the first end cap 24 is provided with a first plug 241, which is locked in the grouting cavity.

[0081] With this configuration, the water inlet 242 provides a high-pressure water injection channel for the water injection chamber to meet the hydraulic expansion requirements; the first plug 241 seals the grouting chamber during the water injection stage to prevent high-pressure water from entering the grouting pipe 15 and interfering with the cleanliness of the grouting chamber, ensuring that the grout channel is not contaminated before grouting.

[0082] When the second end cap 25 is installed on the connecting rod 11, the grouting port 253 is connected to the grouting cavity. The side wall of the second end cap 25 is provided with a drain port 252, which is connected to the water injection cavity. The second end cap 25 is provided with a second plug 251, which is locked in the water injection cavity.

[0083] With this configuration, the grouting port 253 delivers grout to the grouting cavity to meet the grouting reinforcement requirements; the drain port 252 can discharge residual water and gas in the grouting cavity after hydraulic expansion, avoiding water accumulation that could affect the grouting effect; and the second plug 251 seals the grouting cavity during the grouting stage to prevent grout from flowing back into the grouting cavity and causing blockage.

[0084] like Figure 2 , Figure 3 As shown, the grout stopper 14 includes a first retaining ring 141 and a second retaining ring 142. The first retaining ring 141 and the second retaining ring 142 are connected by an elastic sealing ring 143. A spring 148 is provided inside the elastic sealing ring 143. Multiple sets of vent holes 144 are provided on the elastic sealing ring 143. A vent groove 145 is opened on the first retaining ring 141. A filter block 149 is provided inside the vent groove 145. One end of the multiple sets of vent holes 144 is connected to the vent groove 145, and the other end is connected to the drill hole.

[0085] With this configuration, when grouting is not performed, the elastic sealing ring 143 of the grout stop plug 14 is in a naturally relaxed state, only initially adhering to the inner wall of the borehole through the pre-tightening force of the fastening nut 13. At this time, the vent hole 144 on the elastic sealing ring 143 remains unobstructed and forms a complete exhaust channel with the vent groove 145 of the first retaining ring 141. This channel allows residual air or a small amount of gas generated during the hydraulic expansion stage in the borehole to be discharged smoothly, preventing gas from accumulating in the borehole and forming air resistance. At the same time, the filter block 149 in the vent groove 145 can intercept rock cuttings and dust in the borehole, preventing them from clogging the vent hole 144, ensuring that the exhaust channel is always unobstructed, and creating an air resistance-free environment for the subsequent grouting process. During grouting, as grout is continuously injected into the borehole, the pressure inside the grouting chamber gradually increases. When the pressure rises, the grout pressure pushes the second retaining ring 142 of the grout stop plug 14 towards the first retaining ring 141, compressing the elastic sealing ring 143. The elastic sealing ring 143 expands radially after being axially compressed, its outer wall fitting against the inner wall of the borehole, thus sealing the borehole opening. Simultaneously, the deformation of the elastic sealing ring 143 causes the diameter of the vent hole 144 to shrink until it is completely closed, cutting off the exhaust channel and preventing grout leakage from the vent hole 144. During this process, the spring 148 contracts synchronously with the compression of the elastic sealing ring 143, providing elastic support to the elastic sealing ring 143 to prevent excessive deformation and damage, and also helping to maintain the sealing state of the sealing ring during pressure fluctuations, ensuring stable grouting pressure and guaranteeing that the grout fully fills the borehole and surrounding rock fissures.

[0086] The second retaining ring 142 is provided with multiple sets of guide posts 146, and the first retaining ring 141 is provided with multiple sets of first guide grooves 147, with the guide posts 146 and the first guide grooves 147 slidably connected.

[0087] With this configuration, the guide post 146 and the first guide groove 147 work together to constrain the deformation direction of the grout stop plug 14, ensuring that the elastic sealing ring 143 expands uniformly in the radial direction rather than in the axial direction, thus ensuring the symmetry and reliability of the seal and avoiding seal failure due to local displacement.

[0088] Specifically, the end cap plugs achieve the switching and isolation of the "water injection - grouting" process: the first plug 241 and the second plug 251 respectively seal the non-working cavities at their corresponding stages, ensuring that the medium does not flow across; the grout stop plug 14, through the synergy of elastic sealing and a venting structure, achieves reliable sealing under high grouting pressure, and ensures dense grout filling through venting; the guide column 146 further enhances the sealing stability. The overall structure, through functional zoning and process adaptation, allows the two stages of water injection expansion and grouting reinforcement to be orderly connected and do not interfere with each other, ultimately improving the anchoring effect of the anchor bolt.

[0089] like Figure 15 As shown, a method for fixing a sleeve-type hydraulic expansion grouting anchor bolt, applied to the aforementioned sleeve-type hydraulic expansion grouting anchor bolt, includes the following steps: S1 borehole pretreatment: Drill holes in the surrounding rock with a diameter 10-15 mm larger than the outer diameter of the anchor rod, and use high-pressure air to clean the rock debris and water inside the holes.

[0090] A cylindrical anchoring agent 23 is filled into the bottom of the drill hole. The diameter matches the drill hole, and the length is one-third of the length of the insertion rod 22. The center of the anchoring agent 23 is reserved with an insertion hole that matches the insertion rod 22.

[0091] Specifically, a 10-15mm gap is reserved in the borehole diameter to provide space for the subsequent expansion of the expansion shell 16 and grout filling; high-pressure air cleaning can prevent rock debris from obstructing the installation of the anchor rod or the flow of grout. The anchoring agent 23 is filled into the bottom of the borehole and a pre-reserved insertion hole is made, which not only ensures the quick insertion and positioning of the insertion rod 22, but also achieves preliminary anchoring through local curing, preventing the anchor rod from shifting due to loosening of the surrounding rock in the early stage of installation, and providing a stable benchmark for subsequent processes.

[0092] S2 Anchor Bolt Installation: Insert the end of the insertion rod 22 into the pre-drilled hole of the anchoring agent 23, and slowly push the anchor rod until the expansion shell 16 is fully inserted into the borehole, ensuring that the distance between the grouting head 19 and the bottom of the borehole is greater than or equal to 50mm.

[0093] At this time, the vent hole 144 of the grout stop plug 14 remains open, and the guide post 146 is inserted into the first guide groove 147 to a depth of one-quarter of the total stroke.

[0094] Let it stand for 5 to 10 minutes until the anchoring agent 23 has initially cured. When there is no obvious shaking when you hold the anchor rod, it means that the fixing is complete.

[0095] Rotate the fastening nut 13 to move the first retaining ring 141 of the grout stop plug 14 toward the borehole opening, so that the elastic sealing ring 143 initially fits against the inner wall of the borehole.

[0096] Specifically, after the insertion rod 22 is inserted into the pre-drilled hole of the anchoring agent 23, the expansion shell 16 is pushed into the borehole, and the grouting head 19 is kept at a distance of ≥50mm from the bottom of the hole to prevent rock cuttings from clogging the grouting head 19. When the tightening nut 13 is rotated, the first retaining ring 141 of the grout stop plug 14 moves and compresses the elastic sealing ring 143 to initially fit against the hole wall. At this time, the vent hole 144 is open, and the guide post 146 is inserted one-quarter of the way, which not only reserves space for the subsequent expansion of the elastic sealing ring 143, but also ensures its deformation direction through guidance and constraint. At the same time, the vent structure reserves a channel for air to be discharged from the borehole to avoid air blockage during installation. The "no shaking when held by hand" standard after the anchoring agent 23 has initially cured (5-10 minutes) ensures that the anchor rod has the initial bearing capacity to meet the force transmission requirements of subsequent hydraulic expansion.

[0097] S3 hydraulic expansion: Install a first end cap 24 at the end of the connecting rod 11 to ensure that the first plug 241 is in interference fit with the grouting cavity.

[0098] Water is injected into the injection chamber through the injection port 242 at a pressure of 0.8-1.2 MPa. The water pressure pushes the extrusion block 18 to move axially along the grouting pipe 15.

[0099] The second guide groove 181 of the extrusion block 18 slides along the guide rib 166, generating circumferential rotation while advancing axially.

[0100] The spiral petals 161 of the compression expansion section 167 expand radially until the spiral petals 161 fit against the inner wall of the borehole. The fit is determined by the water injection pressure stabilizing at 1.0 MPa.

[0101] During the expansion process, the air in the waterless cavity enters the grouting cavity through the exhaust hole 151 on the grouting pipe 15, and the grouting cavity obtains the initial air pressure.

[0102] Specifically, the first plug 241 of the first end cap 24 seals the grouting cavity to prevent high-pressure water from entering and contaminating it; water pressure of 0.8-1.2 MPa drives the extrusion block 18 to move spirally along the guide rib 166. The spiral angle (e.g., 30° right-handed) causes the extrusion block 18 to rotate and advance simultaneously, ensuring that the spiral petals 161 of the expansion section 167 are subjected to uniform force, achieving radially symmetrical expansion. When the water injection pressure stabilizes at 1.0 MPa, it indicates that the spiral petals 161 are in contact with the borehole wall. Stable pressure means there is no room for continuous expansion, thus completing mechanical anchoring.

[0103] The criterion for determining whether the injection pressure is stable at 1.0 MPa is "pressure fluctuation ≤ ±0.05 MPa for 30 seconds", indicating that the spiral valve 161 has completely adhered to the borehole wall. For soft rock (uniaxial compressive strength ≤ 20 MPa), the initial water pressure is 0.8 MPa, increasing by 0.1 MPa every 30 seconds to 1.0 MPa to avoid rapid expansion leading to borehole wall collapse. For hard rock (≥ 60 MPa), the pressure can be started directly at 1.2 MPa, and maintained for 1 minute after stabilization to enhance the interlocking strength.

[0104] During this stage, air from the waterless chamber enters the grouting chamber through the vent 151, forming an initial air pressure of 0.1-0.2 MPa. This is due to the air accumulation caused by the movement of the extrusion block 18 compressing the waterless chamber. This not only balances the air pressure to prevent air resistance but also provides the basic pressure for the subsequent drainage stage, facilitating rapid air venting and drainage.

[0105] It should be noted that in the initial stage of hydraulic expansion, the water pressure preferentially drives the extrusion block 18 to move axially along the grouting pipe 15. This is because the axial movement resistance between the extrusion block 18 and the grouting pipe 15 is much smaller than the radial expansion resistance of the spiral flap 161 of the expansion section 167. The spiral petal 161 is constrained by the spiral elastic rib 162, resulting in high initial radial stiffness. As high-pressure water is continuously injected, the volume of the water cavity (the side of the extrusion block 18 away from the grouting head 19) increases synchronously with the movement of the extrusion block 18. According to the principle of hydrostatic pressure, the water pressure in the water cavity is always maintained within the injection range of 0.8-1.2 MPa, without significant sudden increase. At this time, the expansion section 167 is only subjected to the initial contact force of the extrusion block 18, and the radial expansion amplitude of the spiral petal 161 is controlled at 0.5-1 mm, only slightly adhering to the inner wall of the borehole. This will not damage the initial seal of the grout stop plug 14 (the elastic sealing ring 143 is only pre-tightened by the fastening nut 13 at this time and is not subjected to high pressure extrusion), and will also prevent the borehole wall from collapsing due to premature stress under soft rock conditions. When the second guide groove 181 of the extrusion block 18 slides along the guide rib 166 to the end of its stroke, that is, when the extrusion block 18 is fully inserted into the second receiving groove 168 on one side of the expansion section 167, the axial movement of the extrusion block 18 is mechanically limited, and the water kinetic energy can no longer be converted into the axial displacement of the extrusion block 18. At this time, the water injection chamber continues to inject high-pressure water, and the volume of the water chamber cannot be further increased. According to Pascal's law, the water pressure will be rapidly transmitted to the spiral petal 161 and the frustum transition section 164 of the expansion section 167. The elastic potential energy of the spiral elastic rib 162 accumulates to a critical value. Under the action of the sudden increase in water pressure (briefly rising to 1.5-1.8MPa), the spiral petal 161 expands rapidly in the radial direction until it engages with the inner wall of the borehole, achieving reliable mechanical anchoring.

[0106] S4 discharges wastewater from the water injection chamber: Remove the first end cap 24 and replace it with the second end cap 25.

[0107] At this time, the drainage block 21 is located at the end of the grouting pipe 15 away from the grouting head 19, and the grouting chamber is connected to the waterless chamber through the vent hole 151.

[0108] Low-pressure grout is injected into the grouting chamber through the grouting port 253 of the second end cap 25. The pressure is 0.2-0.3 MPa. While the grouting pressure pushes the drainage block 21 to move towards the grouting head 19, the air in the grouting chamber enters the waterless chamber through the exhaust port 151 on the grouting pipe 15.

[0109] Under air pressure, the gas in the waterless chamber pushes the one-way valve 183 in the extrusion block 18 to open, and the gas enters the water chamber from the waterless chamber through the one-way valve 183.

[0110] As gas continues to flow in, the pressure inside the water chamber increases, pushing the wastewater inside the chamber out through the drain port 252 of the second end cap 25.

[0111] The drain outlet 252 is connected to the water chamber through the axial channel of the connecting rod 11. Wastewater is continuously discharged along this channel until there is no continuous water flow at the drain outlet 252, at which point it is determined that the water chamber is empty.

[0112] As the drainage block 21 moves, the tip 213 of the drainage block 21 gradually approaches the air barrier membrane 26.

[0113] Specifically, after replacing the second end cap 25, the 0.2-0.3MPa low-pressure grout pushes the drainage block 21 to move. Air from the grouting chamber enters the waterless chamber through the vent 151, and then flows into the water-containing chamber through the one-way valve 183—forming a pressure transmission path of "grouting chamber → waterless chamber → water-containing chamber". As the air pressure in the water-containing chamber increases, it pushes wastewater out through the drain outlet 252. Low-pressure grouting avoids premature triggering of the grout stop plug 14 and gradually squeezes out accumulated water through the movement of the drainage block 21 until there is no continuous water flow at the drain outlet 252, ensuring that residual water in the grouting chamber is completely drained and preventing dilution of subsequent grout. The tip 213 of the drainage block 21 approaches the air-barrier membrane 26, preparing for the next stage of membrane-breaking grouting.

[0114] S5 grouting and filling: Continue to increase the grouting pressure to 0.5-0.6MPa, and the drainage block 21 continues to move until the limiting block 214 contacts the step of the limiting groove 152 on the inner wall of the grouting pipe 15. At this time, the drainage block 21 enters the third receiving groove 193, and the tip 213 of the drainage block 21 pierces the air-sealing membrane 26, and the rupture groove 263 cracks radially.

[0115] The sealing sleeve 215 on the drainage block 21 fits against the inner wall of the grouting pipe 15, completely separating the water injection chamber from the grouting chamber.

[0116] After the air-tight membrane 26 is punctured, the grout enters the grouting groove 191 of the grouting head 19 through the main cavity 211 and the guide hole 212 of the drainage block 21. The grout diffuses into the borehole gap through the multiple sets of radial grouting holes 192 of the grouting head 19.

[0117] Specifically, the grouting pressure of 0.5-0.6MPa pushes the drainage block 21 along the grouting pipe 15 until the limiting block 214 contacts the step of the limiting groove 152 and gets stuck in the third receiving groove 193 to avoid overtravel deviation; on the other hand, the pressure causes the tip 213 of the drainage block 21 to pierce the air-barrier membrane 26, and the radial cracking groove 263 cracks along the preset trajectory to form a smooth grout channel.

[0118] At this time, the sealing sleeve 215 of the drainage block 21 fits against the inner wall of the grouting pipe 15, completely cutting off the connection between the water injection chamber and the grouting chamber, preventing residual water from mixing into the grout; the grout is collected through the main cavity 211 of the drainage block 21, and then evenly distributed to the grouting groove 191 of the grouting head 19 through the radial guide hole 212, and then diffused into the borehole gap through the circumferentially distributed radial grouting holes 192, ensuring that the grout evenly fills the surrounding rock fissures within the anchoring section, thus realizing grouting.

[0119] S6 Exhaust and Sealing Pressure Maintenance: During the grouting process, the residual air in the grouting cavity is discharged through the vent hole 144 of the grout stop plug 14, through the vent groove 145, the gap between the second retaining ring 142 and the connecting rod 11.

[0120] When the grouting pressure rises to 1.0-2.0 MPa, the grout pressure pushes the second retaining ring 142 of the grout stop plug 14 closer to the first retaining ring 141, the elastic sealing ring 143 is axially compressed, the spring 148 contracts, its outer wall fits against the inner wall of the borehole, and at the same time the vent hole 144 is closed due to the deformation of the sealing ring, thus achieving borehole sealing.

[0121] Maintain this pressure for 3 to 5 minutes to ensure the grout is fully filled, then stop grouting.

[0122] Specifically, in the initial stage of grouting, air in the borehole is discharged through the vent hole 144 of the grout stop plug 14 → vent groove 145 → gap between the grout stop plug 14 and the pad plate 12, preventing air from accumulating and forming bubbles that affect the anchoring strength; the filter block 149 can intercept rock cuttings to prevent the vent hole 144 from becoming blocked. When the pressure rises to 1.0-2.0 MPa, the grout pushes the second retaining ring 142 closer to the first retaining ring 141, the elastic sealing ring 143 is axially compressed (with spring 148 assisting in contraction), and radially expands to fit against the borehole wall. At the same time, the vent hole 144 is closed due to the deformation of the sealing ring, achieving complete sealing of the borehole opening. Holding the pressure for 3-5 minutes ensures that the grout fully penetrates the surrounding rock fissures, avoids grout backflow due to sudden pressure drop, and improves the filling density.

[0123] S7 anchoring complete: Remove the second end cap 25, install the plug, and complete the anchor bolt anchoring after the grout has solidified.

[0124] Specifically, removing the second end cap 25 removes the exposed parts of the grouting channel, preventing them from interfering with subsequent operations on the surrounding rock surface (such as shotcreting and support); installing the plug (not shown in the figure, it is a sealing plug that matches the connecting rod 11) can seal the port of the connecting rod 11, preventing dust and moisture from entering the solidified grout and protecting the internal structure of the anchor rod.

[0125] The grouting uses ordinary silicate cement grout, with an initial setting time of 4-6 hours and a final setting time of ≤24 hours. It is then naturally cured at room temperature (15-25℃), reaching the preset strength (≥30MPa) after 72 hours. During the curing period, the anchor bolts must not be disturbed, and the ambient humidity must be maintained at ≥80% to ensure strength development.

[0126] Handling abnormal situations: When the borehole axial deviation angle is ≤5°, the spiral elastic rib 162 of the expansion section 167 can generate radial deformation to compensate for the deviation. The guide rib 166 and the second guide groove 181 reserve a gap to allow the extrusion block 18 to deflect slightly radially, ensuring that the spiral petals 161 can still contact the borehole wall evenly and ensuring that the slurry diffusion range is not affected.

[0127] When the pressure drops suddenly during hydraulic expansion (the drop is greater than 0.3 MPa / 10 seconds): immediately stop water injection, drain water from the drain outlet 252 in the opposite direction to reduce the pressure to 0 MPa, check whether the borehole has collapsed (this can be observed through an endoscope), if the spiral flap 161 is stuck, slowly inject water (below 0.3 MPa) and rotate the connecting rod 11 to release the obstruction and then repressurize.

[0128] If the grout stop plug 14 leaks during grouting: immediately reduce the pressure to 0.5MPa, add a rubber layer to the outside of the expansion section 167 of the grout stop plug 14, and pressurize it by tightening the nut 13. After the leakage stops, slowly increase the pressure back to the preset pressure.

[0129] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A sleeve-type hydraulic expansion grouting anchor bolt, comprising a connecting rod (11) and a pad (12), wherein one end of the connecting rod (11) is located inside a borehole, and the pad (12) has a fastening nut (13) on the side away from the borehole and a grout stopper (14) on the other side, wherein the fastening nut (13) and the grout stopper (14) are both sleeved on the connecting rod (11), characterized in that: The connecting rod (11) is provided with a grouting pipe (15), and the connecting rod (11) is provided with an expansion shell (16) at one end of the borehole. The expansion shell (16) and the connecting rod (11) are connected by a connecting sleeve (17). The expansion shell (16) is provided with an extrusion block (18) at one end near the connecting sleeve (17). The extrusion block (18) is sleeved on the grouting pipe (15), and the expansion shell (16) is provided with a grouting head (19) at one end away from the connecting sleeve (17). One end of the grouting pipe (15) passes through the expansion shell (16) and is connected to the grouting head (19). A drainage block (21) is provided at one end of the grouting pipe (15) away from the grouting head (19). A cutting rod (22) is installed at the end of the grouting head (19) away from the expansion shell (16), and the cutting rod (22) is connected to the borehole by an anchoring agent (23); The connecting rod (11) may be provided with a first end cap (24) or a second end cap (25) at the end away from the borehole. The first end cap (24) is provided with a water inlet (242), and the second end cap (25) is provided with a grouting inlet (253). A grouting cavity is formed inside the grouting pipe (15), and a water injection cavity is formed between the grouting pipe (15), the expansion shell (16), and the connecting rod (11); The expansion shell (16) includes an expansion section (167) and two sets of connecting sections (163). The two sets of connecting sections (163) are located at both ends of the expansion section (167). The connecting sections (163) are connected to the expansion section (167) through a frustum transition section (164). Guide ribs (166) are formed on the expansion section (167) and the frustum transition section (164), and a second guide groove (181) is provided on the outer wall of the extrusion block (18). The guide ribs (166) and the second guide groove (181) are slidably connected. The extrusion block (18) is made of alloy structural steel and is covered with a rubber layer. The extrusion block (18) has multiple sets of ventilation holes (182), and each ventilation hole (182) is equipped with a one-way valve (183).

2. The sleeve-type hydraulic expansion grouting anchor bolt according to claim 1, characterized in that: The expansion section (167) includes multiple sets of spiral petals (161), which are connected by spiral elastic ribs (162). The spiral petals (161) are made of alloy steel, and the spiral elastic ribs (162) are made of spring steel. The two sets of connecting sections (163) are respectively provided with a first receiving groove (165) and a second receiving groove (168) for accommodating the extrusion block (18). The connecting section (163) and the frustum transition section (164) are both made of low alloy steel. The two sets of connecting sections (163) are threadedly connected to the connecting sleeve (17) and the grouting head (19), respectively.

3. The sleeve-type hydraulic expansion grouting anchor bolt according to claim 2, characterized in that: The grouting head (19) is provided with a grouting groove (191) and a plurality of radial grouting holes (192) distributed circumferentially. The grouting head (19) is provided with a third receiving groove (193) for receiving the tip of the drainage block (21).

4. A sleeve-type hydraulic expansion grouting anchor bolt according to claim 3, characterized in that: An air-barrier membrane (26) is provided at the connection between the grouting head (19) and the grouting pipe (15). The air-barrier membrane (26) includes a substrate layer (261) and a metal barrier layer (262) arranged sequentially along the grouting direction. The substrate layer (261) is a polypropylene film, the metal barrier layer (262) is an aluminum film, and the gas barrier membrane (26) is provided with a rupture groove (263), which is radially distributed on the side of the gas barrier membrane (26) near the expansion shell (16).

5. A sleeve-type hydraulic expansion grouting anchor bolt according to claim 4, characterized in that: The drainage block (21) is provided with a flow channel, which includes a main cavity (211) and multiple radially distributed flow holes (212). The drainage block (21) is fitted with a sealing sleeve (215), which is made of nitrile rubber. The drainage block (21) is provided with multiple sets of limiting blocks (214), the limiting blocks (214) are located between two adjacent sets of the guide holes (212), the grouting pipe (15) is provided with a limiting groove (152) for restricting the movement of the limiting blocks (214), and the drainage block (21) is provided with a tip (213) for piercing the air barrier membrane (26) at the end facing the grouting head (19).

6. A sleeve-type hydraulic expansion grouting anchor bolt according to claim 5, characterized in that: The grouting pipe (15) has an exhaust hole (151) at one end near the grouting head (19). When the drainage block (21) moves inside the grouting pipe (15) and the squeezing block (18) is located in the first receiving groove (165): the squeezing block (18) divides the water injection chamber into a waterless chamber and a water-containing chamber. The grouting chamber is connected to the waterless chamber through the vent hole (151). The waterless chamber and the water-containing chamber are connected through the air exchange hole (182). The waterless cavity is located on the side of the extrusion block (18) closer to the grouting head (19), and the water-containing cavity is located on the side of the extrusion block (18) away from the grouting head (19); When the drainage block (21) is located in the third receiving groove (193) and the squeezing block (18) is located in the second receiving groove (168): the drainage block (21) is located on the side of the vent hole (151), separating the water injection chamber and the grouting chamber into independent chambers, and the grouting chamber is connected to the grouting groove (191) through the flow channel of the drainage block (21).

7. A sleeve-type hydraulic expansion grouting anchor bolt according to claim 1, characterized in that: The water inlet (242) is connected to the water injection chamber; The first end cap (24) is provided with a first plug (241), and the first plug (241) is engaged in the grouting cavity; The grouting port (253) is connected to the grouting cavity. The second end cap (25) has a drain port (252) on its side wall. The drain port (252) is connected to the water injection cavity. The second end cap (25) has a second plug (251) which is locked inside the water injection cavity.

8. A sleeve-type hydraulic expansion grouting anchor bolt according to claim 7, characterized in that: The grout stopper (14) includes a first retaining ring (141) and a second retaining ring (142). The first retaining ring (141) and the second retaining ring (142) are connected by an elastic sealing ring (143). A spring (148) is provided inside the elastic sealing ring (143). Multiple sets of vent holes (144) are provided on the elastic sealing ring (143). A vent groove (145) is opened on the first retaining ring (141). A filter block (149) is provided inside the vent groove (145). One end of the multiple sets of vent holes (144) is connected to the vent groove (145), and the other end is connected to the drill hole. The second retaining ring (142) is provided with multiple sets of guide posts (146), and the first retaining ring (141) is provided with multiple sets of first guide grooves (147). The guide posts (146) are slidably connected to the first guide grooves (147).

9. A method for fixing a sleeve-type hydraulic expansion grouting anchor bolt, applied to the sleeve-type hydraulic expansion grouting anchor bolt described in any one of claims 1 to 8, characterized in that: Includes the following steps: S1 borehole pretreatment: Drill holes in the surrounding rock with a diameter 10-15 mm larger than the outer diameter of the anchor bolt, and use high-pressure air to clean the rock cuttings and accumulated water in the holes; A cylindrical anchoring agent (23) is filled into the bottom of the borehole. The diameter matches the borehole, and the length is one-third of the length of the insertion rod (22). An insertion hole adapted to the insertion rod (22) is reserved in the center of the anchoring agent (23). S2 Anchor Bolt Installation: Insert the end of the cutting rod (22) into the pre-drilled hole of the anchoring agent (23), and slowly push the anchor rod until the expansion shell (16) is fully inserted into the borehole, ensuring that the distance between the grouting head (19) and the bottom of the borehole is greater than or equal to 50mm; At this time, the vent hole (144) of the grout stop plug (14) remains open, and the guide post (146) is inserted into the first guide groove (147) to a depth of one-quarter of the total stroke; Let stand for 5 to 10 minutes until the anchoring agent (23) has initially cured. When the anchor rod is held in the hand and there is no obvious shaking, it indicates that the fixing is complete. Rotate the fastening nut (13) to move the first retaining ring (141) of the grout stop plug (14) toward the borehole opening, so that the elastic sealing ring (143) initially fits against the inner wall of the borehole. S3 hydraulic expansion: Install a first end cap (24) at the end of the connecting rod (11) to ensure that the first plug (241) is interference-fitted with the grouting cavity; Water is injected into the injection chamber through the injection port (242) at a pressure of 0.8-1.2 MPa. The water pressure pushes the extrusion block (18) to move axially along the grouting pipe (15). The second guide groove (181) of the extrusion block (18) slides along the guide rib (166), generating circumferential rotation while advancing axially; The spiral petals (161) of the extrusion expansion section (167) expand radially until the spiral petals (161) fit against the inner wall of the borehole. The fit is determined by the water injection pressure stabilizing at 1.0 MPa. During the expansion process, the air in the waterless cavity enters the grouting cavity through the exhaust hole (151) on the grouting pipe (15), and the grouting cavity obtains the initial air pressure; S4 discharges wastewater from the water injection chamber: Remove the first end cap (24) and replace it with the second end cap (25); At this time, the drainage block (21) is located at the end of the grouting pipe (15) away from the grouting head (19), and the grouting chamber is connected to the waterless chamber through the vent hole (151); Low-pressure grout is injected into the grouting chamber through the grouting port (253) of the second end cap (25), with a pressure of 0.2-0.3MPa. The grouting pressure pushes the drainage block (21) to move towards the grouting head (19), while the air in the grouting chamber enters the waterless chamber through the exhaust hole (151) on the grouting pipe (15). Under the action of air pressure, the gas in the waterless chamber pushes the one-way valve (183) in the extrusion block (18) to open, and the gas enters the water chamber from the waterless chamber through the one-way valve (183); As gas continues to flow in, the pressure inside the water chamber increases, pushing the wastewater inside the chamber out through the drain outlet (252) of the second end cap (25); The drain outlet (252) is connected to the water chamber through the axial channel of the connecting rod (11). Wastewater is continuously discharged along this channel until there is no continuous water flow at the drain outlet (252), at which point it is determined that the water chamber is empty. During the movement of the drainage block (21), the tip (213) of the drainage block (21) gradually approaches the air barrier membrane (26). S5 grouting and filling: Continue to increase the grouting pressure to 0.5-0.6MPa, and the drainage block (21) continues to move until the limiting block (214) contacts the step of the limiting groove (152) on the inner wall of the grouting pipe (15). At this time, the drainage block (21) enters the third receiving groove (193), and the tip (213) of the drainage block (21) punctures the air-tight membrane (26), and the rupture groove (263) cracks radially. The sealing sleeve (215) on the drainage block (21) fits against the inner wall of the grouting pipe (15), completely separating the water injection chamber from the grouting chamber; After the air-tight membrane (26) is punctured, the grout enters the grouting groove (191) of the grouting head (19) through the main cavity (211) and the guide hole (212) of the drainage block (21). The grout diffuses into the borehole gap through the multiple sets of radial grouting holes (192) of the grouting head (19). S6 Exhaust and Sealing Pressure Maintenance: During the grouting process, the residual air in the grouting cavity is discharged through the vent hole (144) of the grout stop plug (14) and through the gap between the vent groove (145), the second retaining ring (142) and the connecting rod (11); When the grouting pressure rises to 1.0-2.0 MPa, the grout pressure pushes the second retaining ring (142) of the grout stop plug (14) closer to the first retaining ring (141), the elastic sealing ring (143) is axially compressed, the spring (148) contracts, its outer wall fits against the inner wall of the borehole, and at the same time the vent hole (144) is closed due to the deformation of the sealing ring, thus achieving borehole sealing; Maintain this pressure for 3-5 minutes to ensure the grout is fully filled, then stop grouting; S7 anchoring complete: Remove the second end cap (25), install the plug, and complete the anchor bolt anchoring after the grout has solidified.

Images