Prestressed cable easy-to-retract anchorage device, installation method, lock releasing device and use method

Abstract

This invention relates to the field of anchor cable support technology, and particularly to an easy-release anchor for prestressed anchor cables, its installation method, release device, and usage method. The anchor includes a wedge-shaped member, an inner anchor ring, and an outer anchor ring around the inner anchor ring. The wedge-shaped member and the inner anchor ring are separate structures, while the outer anchor ring is an integral structure. The outer anchor ring and the inner anchor ring form a first conical wedge engagement pair, and the inner anchor ring and the wedge-shaped member form a second conical wedge engagement pair. The taper direction of the first and second conical wedge engagement pairs is configured such that when the anchor cable is tensioned, the wedge-shaped member wedges into the inner anchor ring, and the inner anchor ring wedges into the outer anchor ring. The bottom end of the outer anchor ring has an annular tension portion; during release, the annular tension portion is axially pulled, and the outer anchor ring axially disengages from the inner anchor ring, releasing the radial constraint on the inner anchor ring. This anchor can meet the requirements for high preload anchoring and achieve controllable and rapid release without damaging the components.

Description

Technical Field

[0001] This invention relates to the field of anchor cable support technology, and in particular to a prestressed anchor cable easy-release anchor and its installation method, release device and usage method. Background Technology

[0002] Cable anchors are a common support method in underground engineering projects such as coal mine roadways, traffic tunnels, and high slopes. They clamp the steel strand through the conical wedging action of the anchor ring and wedge-shaped clamps, providing anchoring force and preload to the surrounding rock. Traditional cable anchors typically consist of an anchor ring and two or three wedge-shaped clamps. During tensioning, the clamps wedge into the conical holes inside the anchor ring as the cable retracts, converting the axial tension into radial clamping force, thus achieving self-locking anchoring.

[0003] In practical engineering, when the working face is being mined, temporary supports are being dismantled, or pallets need to be retrieved, some anchor cables require unanchoring. Current unanchoring operations often involve hammering, prying, or forcefully pulling to disengage the wedges from the anchor rings and release the anchor cable. Due to the long-term high preload, the wedges and anchor rings, as well as the wedge teeth and anchor cable surfaces, are tightly interlocked, resulting in significant radial pressure. Conventional unanchoring methods are insufficient to effectively separate the components, often necessitating cutting the anchor cable or damaging the anchor body on-site to complete the removal. This process is not only physically demanding and inefficient, but also prone to safety hazards such as anchor component breakage and sudden anchor cable release. Furthermore, damaged anchors are difficult to reuse.

[0004] In addition, some improved solutions adopt toothed meshing (patent CN206352510U a detachable anchor lock) or threaded connection (patent CN110005455A a quick-release anchor) structures in order to achieve detachability. However, under high preload, dust corrosion and off-center load conditions, the tooth surface is prone to mechanical biting and jamming, and the threaded pair often cannot be properly loosened due to radial deformation or corrosion, resulting in unsatisfactory anchor release reliability. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide an anchorage, installation method, unlocking device, and usage method that can meet the requirements of high preload anchorage and achieve controllable and rapid unlocking without damaging the components.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions: In a first aspect, embodiments of the present invention provide a prestressed anchor cable easy-release anchor, comprising: a wedge-shaped member for being sleeved on the outer periphery of the anchor cable, an inner anchor ring sleeved on the outer periphery of the wedge-shaped member, and an outer anchor ring sleeved on the outer periphery of the inner anchor ring; The wedge-shaped member and the inner anchor ring are both separate structures, while the outer anchor ring is an integral structure. The outer anchor ring and the inner anchor ring form a first conical wedge pair, and the inner anchor ring and the wedge-shaped member form a second conical wedge pair. The taper direction of the first conical wedge pair and the second conical wedge pair is set such that when the anchor cable is tensioned, the wedge-shaped member wedges into the inner anchor ring, and the inner anchor ring wedges into the outer anchor ring. The bottom end of the outer anchor ring is provided with an annular tension part. When the anchor is withdrawn, the annular tension part is axially pulled, and the outer anchor ring is axially separated from the inner anchor ring, releasing the radial constraint on the inner anchor ring.

[0007] As a further technical solution, the angle between the generatrix of the first conical wedge joint and the axis of the anchor cable is 6°-10°.

[0008] As a further technical solution, the inner anchor ring is composed of two ring lobes that extend along the anchor cable axis and are joined together circumferentially, and the joining surface of the two ring lobes is a plane passing through the anchor cable axis.

[0009] As a further technical solution, the wedge-shaped member consists of three wedges distributed circumferentially. The inner surfaces of the three wedges enclose a clamping hole that is adapted to the outer diameter of the anchor cable. The inner surface of the clamping hole is provided with anti-slip teeth, knurling, or circumferential grooves.

[0010] As a further technical solution, the annular tension portion is an annular flange, annular step, or annular groove formed on the outer periphery of the bottom end of the outer anchor ring, and the annular tension portion has a tension end face facing the anchor retraction direction; the axial end of the inner anchor ring is at least partially exposed on the end face of the outer anchor ring.

[0011] As a further technical solution, the anchor is used in conjunction with a spherical pad and a tray, with the tray abutting against the surface of the surrounding rock and the spherical pad positioned between the tray and the inner anchor ring.

[0012] Secondly, embodiments of the present invention provide a method for installing the prestressed anchor cable easy-release anchor as described above, comprising: After the inner anchor ring is assembled, it is fitted onto the outer circumference of the anchor cable; The outer anchor ring is fitted around the outer circumference of the inner anchor ring; Insert the wedge-shaped piece circumferentially between the anchor cable and the inner anchor ring; An axial preload is applied to the outer anchor ring and wedge to form an initial lock between the first and second conical wedge joints. Tension the anchor cable to bring the anchor into a self-locking clamping state.

[0013] Thirdly, embodiments of the present invention provide a release device for the prestressed anchor cable easy-release anchor, including a rear cover, a cylinder barrel, a front cover, bolts, an oil inlet, an oil return port, a hollow oil rod, and an anchor release claw; One end of the anchor release claw is used to hold the annular tension part of the outer anchor ring, and the other end of the anchor release claw is connected to the front cover through the bolt, so that part of the anchor release claw can rotate around the bolt axis between the avoidance position and the holding position, and part of the anchor release claw can retract and rotate between the avoidance position and the holding position. The avoidance position is the passing position of the holding end of the anchor release claw towards the outside of the outer anchor ring, and the holding position is the position where the holding end of the anchor release claw holds the annular tension part. The hollow oil rod is provided with an axial through hole for the anchor cable to pass through, and the front end of the hollow oil rod only abuts against the axial end of the inner anchor ring; When oil pressure is applied into the cylinder through the oil inlet, the hollow oil rod only applies axial support force to the inner anchor ring, driving the retracting anchor claw to pull the outer anchor ring outward along the anchor cable axis.

[0014] As a further technical solution, the front end of the hollow oil rod forms a thrust ring, the inner diameter of the thrust ring is larger than the outer diameter of the wedge to form an axial clearance space, and the outer diameter of the thrust ring is larger than the outer diameter of the inner anchor ring and smaller than the outer diameter of the outer anchor ring. The anchor release claw is a fastening structure, and the fastening end of the anchor release claw is provided with an inner fastening step that cooperates with the annular tension part; The anchoring claws are arranged in a circumferential array on the front cover and are divided into rotating claws and moving claws. The front cover is provided with a round hole and a long slot. The rotating claws are installed on the round hole by bolts, and the moving claws are installed on the long slot by bolts.

[0015] Fourthly, embodiments of the present invention provide a method of using the aforementioned unlocking device, comprising: The hollow oil rod should only abut against the inner anchor ring along the anchor cable axis; Adjust the anchor claw to the avoidance position so that the clamping end of the anchor claw faces outward and passes axially through the outer anchor ring; After the anchor claw passes the outer anchor ring, adjust the anchor claw to the holding position so that the anchor claw engages with the annular tension part of the outer anchor ring; Oil pressure is applied into the cylinder through the oil inlet, so that the hollow oil rod applies axial support force only to the inner anchor ring, while the outer anchor ring is pulled outward along the anchor cable axis by the retraction claw; After the outer anchor ring separates from the inner anchor ring, loosen the bolts, adjust the retractable anchor claw to the avoidance position, remove the outer anchor ring, and then remove the inner anchor ring and wedge in sequence.

[0016] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: 1. Traditional anchor cables, after prolonged exposure to high preload, develop a tight grip between the wedge and the anchor ring, making unanchoring difficult. This often requires hammering, prying, cutting, or forceful pulling, resulting in high workload and safety risks. Furthermore, the anchors are easily damaged and cannot be reused. This anchor utilizes a three-layer, split-type wedge structure. The wedge and inner anchor ring are separate units, while the outer anchor ring is a single unit. The first and second conical wedge joints are configured with their taper directions designed for wedge insertion during tensioning and for releasing the radial constraint during unanchoring by traction of the outer anchor ring. During tensioning, the self-locking characteristic of the conical surface reliably supports high preload. During unanchoring, axial traction of the annular tension portion of the outer anchor ring causes it to disengage first, releasing the radial constraint on the inner anchor ring. The separate inner anchor ring and wedge then naturally loosen. The anchor removal process does not rely on screwing the threaded pair or disengaging the toothed structure. It can better adapt to complex working conditions such as high preload, long-term load, and on-site dust / rust / eccentric load. It fundamentally avoids the problem of destructive operation required due to excessive wedging during anchor removal. It achieves anchor removal with controllable force, without cutting the anchor cable or damaging the main body of the anchor. Moreover, all components of the anchor are intact after anchor removal and can be reused.

[0017] 2. This unlocking device, through the configuration of a rotatable unlocking claw and a hollow hydraulic rod that abuts only against the inner anchor ring, forms a clear axial support and axial traction path: the hollow hydraulic rod applies an inward supporting force to the inner anchor ring, while the unlocking claw applies an outward traction force to the outer anchor ring. These two forces act on different components in opposite directions, directly causing the outer anchor ring to axially separate from the inner anchor ring. The design of the unlocking claw's avoidance and holding positions allows the device to be easily installed on the anchor without being obstructed by the outer anchor ring. Furthermore, the unlocking claw can be locked in the holding position, and the outer diameter of the thrust ring at the front end of the hollow hydraulic rod is larger than the inner diameter of the outer anchor ring. This creates an axial retraction space for the outer anchor ring between the holding end of the unlocking claw and the thrust ring of the hollow hydraulic rod, preventing the outer anchor ring from instantly dislodging. This keeps the outer anchor ring, inner anchor ring, and wedge within the space enclosed by the unlocking claw, preventing damage to the anchor and injury to operators from flying debris.

[0018] Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, the dimensions or spacing between the components are exaggerated to show the position of each component, and the schematic diagrams are for illustrative purposes only.

[0020] Figure 1 This is a cross-sectional structure, a top view of the anchorage, and a schematic diagram of the axial force analysis of the outer anchor ring when the prestressed anchorage of the present invention is installed in the anchorage support structure. Figure 2 The installation steps for the prestressed anchor cable easy-release anchorage of the present invention are as follows; Figure 3 This is a schematic diagram of the unlocking device of the present invention and a cross-sectional structural schematic diagram of its unlocking structure when used in conjunction with the easy-to-unlock anchorage of the prestressed anchor cable; Figure 4 This describes the unlocking steps of the unlocking device of the present invention.

[0021] In the attached diagram: 1. Anchor; 11. Wedge; 12. Inner anchor ring; 13. Outer anchor ring; 2. Unlocking device; 21. Rear cover; 22. Hydraulic cylinder; 23. Front cover; 24. Bolt; 25. Oil inlet; 26. Oil return port; 27. Hollow hydraulic rod; 28. Unlocking claw; 281. Rotating claw; 282. Moving claw; 3. Spherical pad; 4. Tray; 5. Anchoring agent; 6. Surrounding rock; 7. Anchor cable; Detailed Implementation To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the linguistic context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0022] Generally speaking, the terms "include" and "contain" only indicate that the steps and elements are explicitly identified, and these steps and elements do not constitute an exclusive list, as the method or apparatus may also include other steps or elements.

[0023] Example 1 Cable anchoring is an important support method for improving the stability of surrounding rock in engineering projects such as coal mine roadways, traffic tunnels, high slopes, and underground chambers. Commonly used cable anchors typically consist of anchor rings and wedge-shaped clamps. Through the wedge-shaped conical surface and the toothed surface interlocking action, they clamp the steel strand, providing high anchoring force and preload.

[0024] In scenarios such as face mining, temporary support dismantling, roadway maintenance, pallet recycling, or anchor recycling, some anchor cables need to be unanchored. After long-term high preload, traditional wedge-type anchors have a tight fit between the wedge, anchor ring, and anchor cable. On-site, it is often necessary to knock, pry, cut the anchor cable, or pull it forcefully to release the lock. This not only involves high work intensity but also easily causes safety risks such as anchor damage, sudden release of the anchor cable, and personnel approaching the danger source.

[0025] Existing technologies also include solutions to improve anchoring conditions by using outer sleeves, anchoring rings, threaded trays, or special pull-out parts. However, these solutions may still have problems such as indirect force paths, the need to damage or consume additional parts during anchoring, low reusability, insufficient adaptability to high preload conditions, and high requirements for on-site operating space.

[0026] Existing technology CN206352510U discloses a detachable anchor lock, in which the inner and outer locking anchor rings employ a toothed or sawtooth-shaped engagement structure, relying primarily on the meshing of the toothed structures to achieve locking and limiting. In this type of structure, the release contact surface is basically arranged along the anchor cable axis, and the release surface is approximately parallel to the direction of the anchor cable tension. It lacks a conical release angle conducive to the axial disengagement of the outer component; the release angle can be understood as close to 0°. The toothed meshing structure is more prone to mechanical engagement after high preload, making it difficult to achieve stable, rapid, and controllable release.

[0027] Existing technology CN110005455A discloses a quick-release anchorage, whose core structure consists of an anchor ring, a fixed wedge, and an anchor clamp. The fixed wedge has threads on its outer circumference and connects to the internal thread of the anchor ring via these external threads. The release mechanism essentially relies on the threaded connection being loosened or removed during release, thereby relieving the constraint between the anchor ring and the wedge. However, under high preload conditions, its release reliability highly depends on the threaded pair remaining in a screw-able state. After long-term support, high-preload anchor cables experience significant radial clamping forces and local contact stresses between the anchor ring, wedge, and anchor cable. The threaded pair is prone to increased screwing resistance or even inability to be screwed due to radial deformation, pressure engagement, corrosion, coal and rock dust ingress, or uneven loading.

[0028] This embodiment provides a three-layer split wedge-shaped ring structure prestressed anchor 7 with high prestressing force, which is easy to remove. This solves the problems of existing anchor 7 anchors 1, such as difficulty in removal, easy damage to components, high labor intensity, low reusability, and high safety risks. This anchor 1 is mainly used in anchor 7 support scenarios in underground engineering such as coal mine roadways, traffic tunnels, and high slopes. It is especially suitable for situations that require temporary support removal, tray 4 recycling, or anchor reuse.

[0029] like Figure 1As shown, a prestressed anchor cable 7 easy-release anchor 1 includes a wedge-shaped member 11 for sleeved on the outer periphery of the anchor cable 7, an inner anchor ring 12 for sleeved on the outer periphery of the wedge-shaped member 11, and an outer anchor ring 13 for sleeved on the outer periphery of the inner anchor ring 12; the wedge-shaped member 11 and the inner anchor ring 12 are both split structures, while the outer anchor ring 13 is an integral structure; the outer anchor ring 13 and the inner anchor ring 12 form a first conical wedge joint, and the inner anchor ring 12 and the wedge-shaped member 11 form a second conical wedge joint. The taper direction of the first conical wedge joint and the second conical wedge joint is set such that when the anchor cable 7 is tensioned, the wedge-shaped member 11 wedges into the inner anchor ring 12, and the inner anchor ring 12 wedges into the outer anchor ring 13; the bottom end of the outer anchor ring 13 is provided with an annular tension portion, and when the anchor is released, the annular tension portion is axially pulled, and the outer anchor ring 13 axially disengages from the inner anchor ring 12, releasing the radial constraint on the inner anchor ring 12.

[0030] Wedge 11 refers to a ring-shaped split component with an outer conical surface, the inner wall of which is used to clamp the anchor cable 7. Inner anchor ring 12 refers to a split ring-shaped component with both an inner and outer conical surface, located between wedge 11 and outer anchor ring 13. Outer anchor ring 13 refers to an integral ring-shaped load-bearing component with an inner conical surface. A split structure refers to a structure assembled circumferentially from multiple independent parts, capable of radial separation after the loss of external constraints. An integral structure refers to a ring-shaped component machined as a single piece. A conical wedge pair refers to a wedge-tight fit formed by mutually mating inner and outer conical surfaces; when axial load is applied, the conical surface converts the axial force into a radial clamping force. The ring-shaped tension section refers to a structural feature located at the bottom of the outer anchor ring 13, capable of being held by external tools and bearing axial pull-out force.

[0031] The aforementioned components can be made of alloy steel, carbon structural steel, or other metal materials that meet the support strength requirements of the anchor cable 7. The length, wall thickness, heat treatment process, and tooth pattern of the outer anchor ring 13, inner anchor ring 12, and wedge 11 can be selected according to the diameter of the anchor cable 7, the design preload, and the available space. The three-layer split wedge ring structure can be used for the installation of newly installed anchor cables 7, as well as for engineering scenarios where the tray 4, anchor 1, or temporary support components need to be recovered.

[0032] When the anchor cable 7 is tensioned, it pushes the wedge 11 to move towards the surrounding rock 6. Since the outer conical surface of the wedge 11 engages with the inner conical surface of the inner anchor ring 12, the wedge 11 wedges into the inner anchor ring 12. At this time, the inner anchor ring 12 tends to move outward circumferentially. Simultaneously, a frictional force f is generated between the outer conical surface of the inner anchor ring 12 and the inner conical surface of the outer anchor ring 13 due to a force perpendicular to the surface, thus causing the inner anchor ring 12 to wedge into the outer anchor ring 13 and achieve self-locking. The axial load is transmitted step-by-step through the three-layer structure and converted into a radial clamping force on the anchor cable 7, achieving self-locking. During anchor release, the annular tension portion at the bottom of the outer anchor ring 13 is axially pulled by the dedicated unlocking device 2, causing the outer anchor ring 13 to axially disengage from the inner anchor ring 12. Since the outer anchor ring 13 is an integral structure, its inner conical surface forms a radial constraint on the outer conical surface of the inner anchor ring 12. Once the outer anchor ring 13 is axially moved away, this radial constraint is released. At this point, the split inner anchor ring 12 loses its external restraint and can be separated radially, which in turn causes the wedge-shaped part 11 to lose its clamping force and loosen, thus completing the anchor release.

[0033] The three-layer wedge structure increases the contact area for stress and can withstand high preload. By setting the wedge 11 and inner anchor ring 12 as separate parts and the outer anchor ring 13 as an integral part, the mechanism of outer layer constraint and inner layer release is realized. When retracting the anchor, only the outer anchor ring 13 needs to be axially pulled, without cutting the anchor cable 7 or damaging the anchor 1. The operation is controllable and highly safe.

[0034] In a further specific example of this disclosure, the angle between the generatrix of the first conical wedge joint and the axis of the anchor cable 7 is 6°-10°.

[0035] The term "conical generatrix" refers to a straight line on the conical surface. The angle between the generatrix and the axis of the anchor cable 7 determines the taper of the conical surface. The smaller the angle, the stronger the self-locking ability of the wedge pair, but the greater the axial separation force required for anchor removal, and it may even be impossible to disengage due to excessive wedge tightness; the larger the angle, the easier it is to remove the anchor, but the self-locking reliability may decrease during tensioning.

[0036] Testing revealed that when the included angle is less than 6°, even with a wedge-shaped split structure, difficulties in anchor removal can easily arise due to excessively tight wedging, radial deformation, and contact jamming; while when the included angle is greater than 10°, the self-locking performance is insufficient. Controlling the included angle between 6° and 10° ensures that the outer anchor ring 13 and the inner anchor ring 12 can be reliably wedged together without slippage under high preload, while also preventing the wedging pair from seizing up during anchor removal due to an excessively small angle.

[0037] In some other specific examples of this disclosure, the inner anchor ring 12 is composed of two ring lobes that extend axially along the anchor cable 7 and are joined together circumferentially, with the joining surface of the two ring lobes being a plane passing through the axis of the anchor cable 7.

[0038] The inner anchor ring 12 adopts a two-lobed structure, with the two lobes extending axially and their mating surface being a plane passing through the axis of the anchor cable 7, i.e., the two lobes are semi-cylindrical. When the outer anchor ring 13 is fitted around the outer circumference of the inner anchor ring 12, the inner conical surface of the outer anchor ring 13 applies radially inward pressure to the two lobes, forcing the lobes to tightly grip the internal wedge-shaped member 11. During anchor withdrawal, after the outer anchor ring 13 axially disengages, the two lobes lose radial restraint and can separate along the mating surface under their own weight, elastic rebound, or slight external force, thereby releasing the wedge-shaped member 11.

[0039] In a further specific example of this disclosure, the wedge 11 is composed of three wedges distributed circumferentially. The inner surfaces of the three wedges enclose a clamping hole that is adapted to the outer diameter of the anchor cable 7. The inner surface of the clamping hole is provided with anti-slip teeth, knurling, circumferential grooves or rough friction-enhancing surfaces.

[0040] Three wedges are evenly distributed circumferentially, each with an inner arc surface. When assembled, they form a circular clamping hole with a diameter approximately the same as the outer diameter of the anchor cable 7. To increase the frictional clamping force on the anchor cable 7, the inner surface of the clamping hole is equipped with anti-slip serrations or knurling. The three-part structure can more evenly transmit radial clamping force, preventing the wedge 11 from deflecting under force. Furthermore, the three wedges are easier to separate from the anchor cable 7 during anchor withdrawal.

[0041] In some other specific examples of this disclosure, the annular tension portion is an annular flange, annular step, or annular groove formed on the outer periphery of the bottom end of the outer anchor ring 13, and the annular tension portion has a tension end face facing the anchoring direction; the axial end of the inner anchor ring 12 is at least partially exposed on the end face of the outer anchor ring 13.

[0042] The specific form of the annular tension portion can be an outwardly convex annular flange, a machined annular step, or an annular groove, as long as it provides a tension end face for the anchor release claw 28 to hold. When the anchor release claw 28 holds and applies axial tension, the force is clearly defined. In addition, the axial end of the inner anchor ring 12 is exposed on the end face of the outer anchor ring 13, allowing the hollow oil rod 27 to directly abut against the end of the inner anchor ring 12 during anchor release.

[0043] In a further specific example of this disclosure, the anchor 1 is used in conjunction with a spherical pad 3 and a tray 4, the tray 4 being abutted against the surface of the surrounding rock 6, and the spherical pad 3 being disposed between the tray 4 and the inner anchor ring 12.

[0044] The tray 4 is a large-area pad that fits tightly against the surface of the surrounding rock 6. It is used to distribute the tension of the anchor cable 7 to the surrounding rock 6, preventing local crushing of the surrounding rock 6. The spherical pad 3 has a spherical fit structure, which can automatically adjust its angle to adapt to situations where the anchor cable 7 is not perpendicular to the surface of the surrounding rock 6, thus avoiding the anchor 1 bearing additional bending moment. During installation, the spherical pad 3 is located between the tray 4 and the inner anchor ring 12. That is, the end of the inner anchor ring 12 is pressed against the tray 4 by the spherical pad 3, and the tray 4 then presses against the surrounding rock 6, ensuring that the anchor cable 7 is subjected to uniform force and improving the reliability of the support system.

[0045] In summary, the three-layer wedge structure of the anchor 1 increases the contact area under stress, enabling it to accommodate high-preload anchor cables 7 and improve locking stability. The included angle θ, controlled between 6° and 10°, balances the self-locking reliability of the outer anchor ring 13 and the separability of the inner anchor ring 12 during anchor removal. The integrated outer anchor ring 13 serves as the overall load-bearing ring, supporting the outer constraint, while the two-part inner anchor ring 12 and wedge-shaped component 11 act as separate release structures, balancing locking reliability and ease of anchor removal. The anchor 1 is not easily damaged after anchor removal, can be reused, and reduces support and recycling costs.

[0046] Example 2 This embodiment provides a method for using the easy-release anchor 1 of the prestressed anchor cable 7 described in Embodiment 1, including: installing the tray 4 and the spherical pad 3 on the exposed section of the anchor cable 7 and abutting it against the surface of the surrounding rock 6; assembling the inner anchor ring 12 and then fitting it around the outer periphery of the anchor cable 7; fitting the outer anchor ring 13 around the outer periphery of the inner anchor ring 12; inserting the wedge 11 circumferentially between the anchor cable 7 and the inner anchor ring 12; applying an axial preload to the outer anchor ring 13 and the wedge 11 to form an initial locking of the first conical wedge pair and the second conical wedge pair; and tensioning the anchor cable 7 to bring the anchor 1 into a self-locking clamping state.

[0047] First, install the tray 4 and the spherical pad 3, then install the inner anchor ring 12, as follows. Figure 2 As shown, the inner anchor ring 12 is assembled and then fitted onto the anchor cable 7; that is, the two ring segments are first closed and then fitted onto the anchor cable 7. Next, the outer anchor ring 13 is fitted in, and then the three wedges of the wedge-shaped member 11 are sequentially inserted into the gap between the anchor cable 7 and the inner anchor ring 12. Applying axial preload is to ensure that the conical surfaces initially fit together, eliminate gaps, and ensure uniform stress on each component during subsequent tensioning. Finally, the anchor cable 7 is tensioned, and the anchor 1 automatically enters a self-locking state by utilizing the retraction tendency of the anchor cable 7. The anchor cable 7 can be anchored to the surrounding rock 6 using the anchoring agent 5.

[0048] This method of use provides a complete assembly sequence from tray 4, spherical pad 3 to inner anchor ring 12, outer anchor ring 13, and wedge 11, ensuring the correct fit of each conical surface and creating conditions for the smooth disengagement of outer anchor ring 13 during subsequent anchor removal.

[0049] Example 3 When using a conventional puller to unanchor the existing anchor 1, due to the large force, the outer anchor ring 13 will pop out axially at the moment of unanchoring, and the inner split anchor ring or wedge 11 will jump out in all directions, which will not only damage the anchor 1, but also pose a great safety risk to the operator.

[0050] Based on this, this embodiment provides a release device 2 for the easily release anchorage 1 of the prestressed anchor cable 7, such as... Figure 3 As shown, the system includes a rear cover 21, a cylinder barrel 22, a front cover 23, a bolt 24, an oil inlet 25, an oil return port 26, a hollow oil rod 27, and an anchor release claw 28. One end of the anchor release claw 28 is used to hold the annular tension portion of the outer anchor ring 13, and the other end of the anchor release claw 28 is connected to the front cover 23 via the bolt 24, allowing part of the anchor release claw 28 to rotate around the axis of the bolt 24 between a clearance position and a holding position. Part of the anchor release claw 28 can retract and rotate between the clearance position and the holding position. The clearance position is the position where the anchor release claw 28... The holding end faces the outer side of the outer anchor ring 13. The holding position is when the holding end of the retracting anchor claw 28 rotates to the bottom of the outer anchor ring 13 and holds the annular tension part. The hollow oil rod 27 is provided with an axial through hole for the anchor cable 7 to pass through, and the front end of the hollow oil rod 27 only abuts against the axial end of the inner anchor ring 12. When oil pressure is applied to the oil cylinder through the oil inlet 25, the hollow oil rod 27 only applies axial support force to the inner anchor ring 12, driving the retracting anchor claw 28 to pull the outer anchor ring 13 outward along the axial direction of the anchor cable 7.

[0051] The unlocking device 2 is a hydraulically driven hollow cylinder assembly. The rear cover 21, cylinder barrel 22, and front cover 23 constitute the cylinder housing. The inlet port 25 and outlet port 26 control the flow of hydraulic oil. The hollow rod 27 is the piston rod; its hollow structure allows the anchor cable 7 to pass through, enabling the device to be fitted onto the outer end of the anchor cable 7. When installing the unlocking device 2, first adjust the unlocking claw 28 to the clearance position, with the clamping end facing outwards from the outer anchor ring 13, i.e., radially outwards, so that the unlocking claw 28 can smoothly pass axially through the outer anchor ring 13 without being blocked by the annular tension part. After the clamping end of the unlocking claw 28 passes through the outer anchor ring 13, adjust it to the clamping position, rotating the clamping end to the bottom of the outer anchor ring 13 and hooking the annular tension part. Then tighten the bolt 24 to lock the unlocking claw 28.

[0052] During anchor retraction, hydraulic oil pushes the hollow hydraulic rod 27 forward. Since the front end of the hollow hydraulic rod 27 only abuts against the axial end of the inner anchor ring 12, the hollow hydraulic rod 27 applies an inward axial support force to the inner anchor ring 12. Simultaneously, the front cover 23 of the cylinder drives the anchor retraction claw 28 to move outward, and the anchor retraction claw 28 pulls the outer anchor ring 13 outward. The inner anchor ring 12 is subjected to an inward force, and the outer anchor ring 13 is subjected to an outward force, resulting in relative axial displacement between the two, causing the outer anchor ring 13 to detach from the inner anchor ring 12.

[0053] In some other specific examples of this disclosure, the front end of the hollow oil rod 27 forms a thrust ring, the inner diameter of the thrust ring is larger than the outer diameter of the wedge 11 to form an axial clearance space, the outer diameter of the thrust ring is larger than the outer diameter of the inner anchor ring 12 and smaller than the outer diameter of the outer anchor ring 13; the anchor release claw 28 is a two-claw, three-claw or ring-shaped clamping structure, and the clamping end of the anchor release claw 28 is provided with an inner clamping step that cooperates with the annular tension part.

[0054] The front end of the hollow hydraulic rod 27 forms a thrust ring, which is a radially enlarging annular step. The inner diameter of the thrust ring is larger than the outer diameter of the wedge 11, meaning the thrust ring will not contact the wedge 11, allowing for axial clearance. The outer diameter of the thrust ring is larger than the outer diameter of the inner anchor ring 12, or in other words, larger than the inner diameter of the outer anchor ring 13. At the same time, the outer diameter of the thrust ring is smaller than the outer diameter of the outer anchor ring 13, allowing the end face of the thrust ring to abut against the end face of the inner anchor ring 12, and providing axial restraint to the outer anchor ring 13, preventing the outer anchor ring 13 from flying out during anchor retraction.

[0055] The anchor release claw 28 adopts a two-claw, three-claw, or ring-shaped structure. The two-claw type has two symmetrical claws arranged in the diameter direction, the three-claw type has three claws evenly distributed in the circumference, and the ring-shaped type has a complete ring claw. The locking end of the claw is provided with an inner locking step. The shape of the step matches the flange or groove of the ring tension part, which can reliably hook the ring tension part without slipping.

[0056] Specifically, the anchoring claws 28 are arranged in a circumferential array on the front cover 23, and are divided into rotating claws 281 and moving claws 282. The front cover 23 is provided with a round hole and a long slot. The rotating claws 281 are installed on the round hole by bolts 24, and the moving claws 282 are installed on the long slot by bolts 24.

[0057] like Figure 4 As shown, during operation, first rotate all the anchor release claws 28 outwards, and move the moving claw 282 radially outwards along the elongated groove. After passing through the outer anchor ring 13, first rotate the rotating claw 281 inwards and fix it, then rotate the moving claw 282 inwards, and then push the moving claw 282 radially inwards so that all the anchor release claws 28 are engaged on the outer anchor ring 13, and tighten the bolt 24.

[0058] When the anchor release device 2 releases the anchor, the hollow oil rod 27 supports the inner anchor ring 12, and the anchor release claw 28 pulls the outer anchor ring 13. The force path is clear and the release process is controllable. The anchor release claw 28 can first avoid the outer anchor ring 13 before locking it, which reduces the difficulty of on-site installation and ensures the safety of the anchor release.

[0059] Example 4 This embodiment provides a method for using the unlocking device 2 of Embodiment 3, including: making the hollow oil rod 27 abut against the inner anchor ring 12 along the axial direction of the anchor cable 7; adjusting the unlocking claw 28 to the avoidance position, so that the holding end of the unlocking claw 28 faces outward and passes through the outer anchor ring 13 axially; after the unlocking claw 28 passes through the outer anchor ring 13, adjusting the unlocking claw 28 to the holding position, so that the unlocking claw 28 locks the annular tension part of the outer anchor ring 13; applying oil pressure to the oil cylinder through the oil inlet 25, so that the hollow oil rod 27 applies axial support force only to the inner anchor ring 12, while the unlocking claw 28 pulls the outer anchor ring 13 outward along the axial direction of the anchor cable 7; after the outer anchor ring 13 is separated from the inner anchor ring 12, loosening the bolt 24, rotating the unlocking claw 28 radially to the avoidance position, removing the outer anchor ring 13, and then removing the inner anchor ring 12 and the wedge 11 in sequence.

[0060] First, temporary support measures were implemented, and it was confirmed that no personnel were in danger zone around anchor cable 7. The unlocking device 2 was arranged coaxially with anchor 1, ensuring that the front end of hollow hydraulic rod 27 only abutted the end of inner anchor ring 12; Figure 4 As shown, first rotate all the anchor release claws 28 outwards, and move the moving claw 282 radially outwards along the elongated groove, so that the holding end of the anchor release claw 28 faces outwards so that the anchor release claw 28 passes through the outer anchor ring 13; after passing through, first rotate the rotating claw 281 inwards and fix it, then rotate the moving claw 282 inwards, and then push the moving claw 282 radially inwards so that all the anchor release claws 28 are engaged with the annular tension part at the bottom of the outer anchor ring 13, and tighten the bolt 24. Apply oil pressure to the oil cylinder through the oil inlet 25, and the hollow oil rod 27 applies axial support force only to the inner anchor ring 12. The front cover 23 drives the anchor release claws 28 through the bolt 24 to apply an axial pull force in the opposite direction to the outer anchor ring 13. As the oil pressure gradually increases, the outer anchor ring 13 disengages from the inner anchor ring 12 along the axial direction of the anchor cable 7, and the first conical wedge joint is released. Loosen the bolt 24 fixing the anchor release claw 28, turn the anchor release claw 28 to the clearance position, and remove the outer anchor ring 13.

[0061] After the outer anchor ring 13 detaches, the inner anchor ring 12 is no longer radially constrained by the outer anchor ring 13 and can separate radially under its own weight, elastic rebound, or slight external force; the wedge 11 then loosens its grip on the anchor cable 7. The operator removes the outer anchor ring 13, the inner anchor ring 12, and the wedge 11 in sequence, thus completing the anchor removal.

[0062] During the anchor release process, pressure should be applied in stages, and after the outer anchor ring 13 generates initial displacement, the holding status of the anchor release claw 28, the coaxial status of the hollow oil rod 27, and the offset of the anchor 1 should be checked to ensure that the release process is smooth and controllable.

[0063] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A prestressed cable easy-release anchorage, characterized in that, include: A wedge-shaped piece fitted around the outer periphery of an anchor cable, an inner anchor ring fitted around the outer periphery of the wedge-shaped piece, and an outer anchor ring fitted around the outer periphery of the inner anchor ring; The wedge-shaped member and the inner anchor ring are both separate structures, while the outer anchor ring is an integral structure. The outer anchor ring and the inner anchor ring form a first conical wedge pair, and the inner anchor ring and the wedge-shaped member form a second conical wedge pair. The taper direction of the first conical wedge pair and the second conical wedge pair is set such that when the anchor cable is tensioned, the wedge-shaped member wedges into the inner anchor ring, and the inner anchor ring wedges into the outer anchor ring. The bottom end of the outer anchor ring is provided with an annular tension part. When the anchor is withdrawn, the annular tension part is axially pulled, and the outer anchor ring is axially separated from the inner anchor ring, releasing the radial constraint on the inner anchor ring.

2. The prestressed anchor cable easy-release anchorage as described in claim 1, characterized in that, The angle between the generatrix of the first conical wedge joint and the axis of the anchor cable is 6°-10°.

3. The prestressed anchor cable easy-release anchorage as described in claim 1, characterized in that, The inner anchor ring consists of two ring lobes that extend along the anchor cable axis and are joined together circumferentially. The joining surface of the two ring lobes is a plane passing through the anchor cable axis.

4. The prestressed anchor cable easy-release anchorage as described in claim 1, characterized in that, The wedge-shaped component consists of three wedges distributed circumferentially. The inner surfaces of the three wedges enclose a clamping hole that is adapted to the outer diameter of the anchor cable. The inner surface of the clamping hole is provided with anti-slip teeth, knurling, or circumferential grooves.

5. The prestressed anchor cable easy-release anchorage as described in claim 1, characterized in that, The annular tension portion is an annular flange, annular step, or annular groove formed on the outer periphery of the bottom end of the outer anchor ring, and the annular tension portion has a tension end face facing the anchor retraction direction; the axial end of the inner anchor ring is at least partially exposed on the end face of the outer anchor ring.

6. The prestressed anchor cable easy-release anchorage as described in claim 1, characterized in that, The anchor is used in conjunction with a spherical pad and a tray, with the tray resting against the surface of the surrounding rock and the spherical pad positioned between the tray and the inner anchor ring.

7. A method for installing a prestressed anchor cable easy-release anchor as described in any one of claims 1-6, characterized in that, include: After the inner anchor ring is assembled, it is fitted onto the outer circumference of the anchor cable; The outer anchor ring is fitted around the outer circumference of the inner anchor ring; Insert the wedge-shaped piece circumferentially between the anchor cable and the inner anchor ring; An axial preload is applied to the outer anchor ring and wedge to form an initial lock between the first and second conical wedge joints. Tension the anchor cable to bring the anchor into a self-locking clamping state.

8. A release device for an easily releasable prestressed anchor cable as described in any one of claims 1-6, characterized in that, Includes rear cover, cylinder barrel, front cover, bolts, oil inlet, oil outlet, hollow oil rod, and anchor release claw; One end of the anchor release claw is used to hold the annular tension part of the outer anchor ring, and the other end of the anchor release claw is connected to the front cover through the bolt, so that part of the anchor release claw can rotate around the bolt axis between the avoidance position and the holding position, and part of the anchor release claw can retract and rotate between the avoidance position and the holding position. The avoidance position is the passing position of the holding end of the anchor release claw towards the outside of the outer anchor ring, and the holding position is the position where the holding end of the anchor release claw holds the annular tension part. The hollow oil rod is provided with an axial through hole for the anchor cable to pass through, and the front end of the hollow oil rod only abuts against the axial end of the inner anchor ring; When oil pressure is applied into the cylinder through the oil inlet, the hollow oil rod only applies axial support force to the inner anchor ring, driving the retracting anchor claw to pull the outer anchor ring outward along the anchor cable axis.

9. The unlocking device as described in claim 8, characterized in that, The front end of the hollow oil rod forms a thrust ring. The inner diameter of the thrust ring is larger than the outer diameter of the wedge to form an axial clearance space. The outer diameter of the thrust ring is larger than the outer diameter of the inner anchor ring and smaller than the outer diameter of the outer anchor ring. The anchor release claw is a fastening structure, and the fastening end of the anchor release claw is provided with an inner fastening step that cooperates with the annular tension part; The anchoring claws are arranged in a circumferential array on the front cover and are divided into rotating claws and moving claws. The front cover is provided with a round hole and a long slot. The rotating claws are installed on the round hole by bolts, and the moving claws are installed on the long slot by bolts.

10. A method of using the unlocking device as described in claim 8 or 9, characterized in that, include: The hollow oil rod should only abut against the inner anchor ring along the anchor cable axis; Adjust the anchor claw to the avoidance position so that the clamping end of the anchor claw faces outward and passes axially through the outer anchor ring; After the anchor claw passes the outer anchor ring, adjust the anchor claw to the holding position so that the anchor claw engages with the annular tension part of the outer anchor ring; Oil pressure is applied into the cylinder through the oil inlet, so that the hollow oil rod applies axial support force only to the inner anchor ring, while the outer anchor ring is pulled outward along the anchor cable axis by the retraction claw; After the outer anchor ring separates from the inner anchor ring, loosen the bolts, adjust the retractable anchor claw to the avoidance position, remove the outer anchor ring, and then remove the inner anchor ring and wedge in sequence.

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