Combined pre-stressed anchor rod and anchoring construction method thereof

Abstract

The invention provides a combined type pre-stressed anchor rod and an anchoring construction method thereof, and belongs to the technical field of engineering construction.The combined type pre-stressed anchor rod comprises an anchor rod body, a first pre-stressed anchor rod body and a second pre-stressed anchor rod body, the sleeve is arranged on the anchor rod body in a sleeving manner; the pre-tightening assembly is arranged on the first threaded end and used for being in threaded fit with the first threaded end during anchoring so as to pre-tighten the anchor rod body and change the position of the second threaded end; the combined anchor head is in threaded connection with the second threaded end; the expansion wedge body is provided with an opening end, and the combined anchor head can stretch into the expansion wedge body through the opening end under the pre-tightening effect so as to expand the expansion wedge body to achieve anchoring. The device has multiple anchoring mechanisms, so that the anchoring stability and reliability can be enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of engineering construction, and in particular to a combined prestressed anchor rod and an anchoring construction method thereof. Background Art

[0002] Anchor support is one of the most important support methods for solving underground engineering problems and is widely used in tunnel, hydropower station, mine construction and other fields throughout the world.

[0003] However, the existing anchor technology is difficult to meet different construction requirements. The existing anchor support mostly uses resin anchors, pipe seam anchors, and expansion shell prestressed anchors. It has certain structural problems and high material costs, complex construction processes, and high construction requirements. At the same time, the anchoring mechanism is relatively simple and the anchoring reliability is poor. In addition, the problem of prestress loss will occur during the prestressing stage, affecting the overall structural stability of the structure. If effective measures are not taken, it is easy to lead to substandard project quality, causing engineering safety hazards, and seriously endangering the safety of personnel and subsequent engineering use.

[0004] Therefore, there is an urgent need for an anchor rod with multiple anchoring mechanisms to solve the existing construction technology problems. Summary of the invention

[0005] The object of the present invention is to overcome at least one of the above-mentioned deficiencies of the prior art and to provide a combined prestressed anchor rod with multiple anchoring mechanisms.

[0006] Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

[0007] According to one aspect of the present invention, there is provided a combined prestressed anchor rod, comprising: An anchor body having a first threaded end and a second threaded end disposed opposite to each other; A sleeve, sleeved on the anchor body; A pre-tightening assembly, disposed on the first threaded end, for threadably cooperating with the first threaded end during anchoring to pre-tighten the anchor rod body and change the position of the second threaded end; A combined anchor head, threadedly connected to the second threaded end; The expansion wedge body has an open end, and the combined anchor head can extend into the expansion wedge body through the open end under the action of pre-tightening to expand the expansion wedge body and realize anchoring.

[0008] In some exemplary embodiments of the present invention, based on the aforementioned solution, the sleeve has a first connecting end; Wherein, the first connecting end is an end close to the second threaded end, and the first connecting end is connected to the connecting end of the expansion wedge.

[0009] In some exemplary embodiments of the present invention, based on the aforementioned solution, the first connecting end is connected to the connecting end of the expansion wedge in a ring pressing manner.

[0010] In some exemplary embodiments of the present invention, based on the above solution, the sleeve further has a second connecting end, and the second connecting end is an end close to the first threaded end; The combined prestressed anchor rod also includes a sleeve clamping ring, and the sleeve clamping ring is sleeved on the second connecting end.

[0011] In some exemplary embodiments of the present invention, based on the aforementioned solution, the combined prestressed anchor rod further includes a limiting ring, which is disposed at a middle position inside the sleeve to limit the installation position and movement position of the anchor rod body.

[0012] In some exemplary embodiments of the present invention, based on the aforementioned solution, the pre-tightening assembly includes: a torque nut, wherein an internal thread in the torque nut is threadably matched with an external thread of the first threaded end.

[0013] In some exemplary embodiments of the present invention, based on the aforementioned solution, the pre-tightening assembly further includes: a tray, which is sleeved on the anchor rod body and arranged away from the first threaded end; and a gasket, which is sleeved on the anchor rod body and located between the tray and the torque nut.

[0014] In some exemplary embodiments of the present invention, based on the aforementioned solution, the gasket is a spherical gasket.

[0015] According to another aspect of the present invention, there is provided a method for anchoring a combined prestressed anchor rod, the method comprising: S1: Drill anchor holes on the working surface; S2: Pushing the combined prestressed anchor rod into the anchor rod hole to achieve full-length anchoring; S3: Turn the torque nut. When the combined anchor head is embedded in the expansion wedge and the expansion wedge is fully squeezed open, continue to turn the torque nut until the first thread end stops moving, thereby completing the anchoring.

[0016] In some exemplary embodiments of the present invention, based on the above solution, the diameter of the anchor hole is smaller than the diameter of the sleeve before closing.

[0017] It can be seen from the above technical solution that the present invention has the following advantages and positive effects: On the one hand, the anchor body can be effectively pre-tightened by cooperating the pre-tightening component with the thread of the first threaded end. This puts the anchor in a certain tension state before use, provides a stable foundation for subsequent anchoring work, and enhances the reliability and firmness of the anchor during work. On the other hand, the pre-tightening operation can change the position of the combined anchor head, which enables the shape and position of the anchor to be flexibly adjusted under different working scenarios and anchoring requirements to adapt to various complex installation conditions. When the combined anchor head extends into the expansion wedge under the action of pre-tightening and spreads the expansion wedge, anchoring can be achieved quickly and firmly. This anchoring method is relatively simple to operate, and the method of spreading the expansion wedge can evenly distribute the anchoring force, thereby effectively improving the anchoring effect and stability.

[0018] In addition, a full-length anchoring can be formed between the sleeve and the anchor hole, and the cooperation between the expansion wedge and the combined anchor head can achieve double-end anchoring. Therefore, the combined prestressed anchor provided by the present invention has multiple anchoring mechanisms, thereby enhancing the anchoring stability and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

[0020] Figure 1 It is a structural schematic diagram of an embodiment of a combined prestressed anchor rod of the present invention; Figure 2 It is a structural schematic diagram of another embodiment of the combined prestressed anchor rod of the present invention; Figure 3 is a flow chart of the anchoring construction method of the present invention; Figure 4 It is a schematic diagram of the working principle of the sleeve; Figure 5 Schematic diagram of the working principle of the expansion wedge; Figure 6 It is a schematic diagram of the principle of the anchoring construction method of the present invention.

[0021] Description of Reference Numerals 1. Anchor rod body; 2. Torque nut; 3. Gasket; 4. Tray; 5. Sleeve clamp; 6. Sleeve; 7. Limit ring; 8. Expansion wedge; 9. Combined anchor head. DETAILED DESCRIPTION

[0022] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present invention will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted.

[0023] The features, structures or characteristics described above may be combined in one or more embodiments in any suitable manner, and if possible, the features discussed in each embodiment are interchangeable. In the above description, many specific details are provided to provide a full understanding of the embodiments of the present invention. However, those skilled in the art will appreciate that the technical solution of the present invention may be practiced without one or more of the specific details, or other methods, components, materials, etc. may be adopted. In other cases, known structures, materials or operations are not shown or described in detail to avoid blurring various aspects of the present invention.

[0024] Although relative terms such as "upper" and "lower" are used in the present invention to describe the relative relationship of one component of the illustration to another component, these terms are used in the present invention only for convenience, such as the orientation of the examples described in the drawings. It is understood that if the device of the illustration is turned over and turned upside down, the component described as being "upper" will become the component "lower". Other relative terms such as "high", "low", "top", "bottom", "front", "back", "left", "right", etc. are also used to have similar meanings. When a structure is "on" other structures, it may mean that the structure is formed integrally on the other structure, or that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure through another structure.

[0025] In the present invention, the terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "comprising", "including" and "having" are used to express an open-ended inclusion and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.

[0026] According to one aspect of the present invention, there is provided a combined prestressed anchor rod, Figure 1 and Figure 2 As shown, the combined prestressed anchor includes: The anchor rod body 1 has a first threaded end and a second threaded end arranged opposite to each other; A sleeve 6 is sleeved on the anchor body 1; The pre-tightening assembly is arranged on the first threaded end and is used to cooperate with the first threaded end thread during anchoring to pre-tighten the anchor rod body 1, change the position of the second threaded end (the rod body moves upward relative to the end nut, driving the second threaded end expansion body to squeeze the expansion wedge body 8, expand inside the anchor rod hollow, and realize end anchoring.

[0027] A combined anchor head 9, threadedly connected to the second threaded end; The expansion wedge 8 has an open end, and the combined anchor head 9 can extend into the expansion wedge 8 through the open end under the action of pre-tightening to expand the expansion wedge 8 and squeeze the rock wall to achieve end anchoring.

[0028] On the one hand, the anchor body 1 can be effectively pre-tightened by the cooperation between the pre-tightening component and the thread of the first threaded end. This puts the anchor in a certain tension state before use, provides a stable foundation for subsequent anchoring work, and enhances the reliability and firmness of the anchor during work. On the other hand, the pre-tightening operation can change the position of the combined anchor head 9, which enables the shape and position of the anchor to be flexibly adjusted under different working scenarios and anchoring requirements to adapt to various complex installation conditions. When the combined anchor head 9 extends into the expansion wedge 8 and spreads the expansion wedge 8 under the action of pre-tightening, anchoring can be achieved quickly and firmly. This anchoring method is relatively simple to operate, and the method of spreading the expansion wedge 8 can evenly distribute the anchoring force, thereby effectively improving the anchoring effect and stability.

[0029] In addition, a full-length anchoring can be formed between the sleeve 6 and the anchor hole, and the cooperation between the expansion wedge 8 and the combined anchor head 9 can achieve double end anchoring. Therefore, the combined prestressed anchor provided by the present invention has multiple anchoring mechanisms, thereby enhancing the anchoring stability and reliability.

[0030] The present invention does not impose any specific restrictions on the structure of the pre-tightening assembly. For example, in some embodiments, a sleeve 6 structure with an internal thread may be used, and the internal thread of the sleeve 6 is adapted to the external thread of the first threaded end. The sleeve 6 is rotated to move along the first threaded end, thereby achieving the pre-tightening operation of the anchor body 1. Alternatively, a structure composed of a plurality of adjustable wedge blocks may be used, and these wedge blocks are installed around the first threaded end, and the pre-stress of the anchor body 1 is changed by adjusting the position of the wedge blocks. A combined structure with a coil spring and an adjusting nut may also be used, wherein the coil spring is sleeved on the outside of the first threaded end, and the adjusting nut is screwed on the thread of the first threaded end and squeezes the coil spring, and the compression degree of the spring is changed by screwing the adjusting nut in and out, thereby achieving the pre-tightening adjustment of the anchor body 1.

[0031] In the embodiment provided by the present invention, the pre-tightening assembly includes a torque nut 2, and the internal thread in the torque nut 2 cooperates with the external thread on the first thread end. On the one hand, the torque nut 2 converts the externally applied rotational force into a prestress along the axial direction of the anchor rod through the threaded connection with the first thread end, so that the anchor rod body 1 is in a certain tension state before anchoring, thereby playing a role in transmitting the prestress; on the other hand, when anchoring, the threaded connection structure of the torque nut 2 can prevent the sudden relaxation or fluctuation of the prestress through the friction and bite force between the threads when the anchor rod is subjected to external force, thereby maintaining the stability of the anchoring system. Thereby, it can play a role in stabilizing the tightening force. In addition, the torque nut 2 can be precisely rotated and adjusted according to actual needs, so as to flexibly control the size of the prestress to adapt to different anchoring conditions and requirements. At the same time, its sturdy structure and reliable threaded connection method can maintain good working performance during long-term use and is not easily invalidated due to environmental factors or external force impact.

[0032] In addition, in order to be able to diffuse the prestress while reinforcing the surrounding rock and organizing the movement and deformation of the surrounding rock. In the exemplary embodiment provided by the present invention, the pre-tightening assembly also includes a tray 4, which is sleeved on the anchor body 1 and is arranged away from the first threaded end. On the one hand, since the tray 4 has a large contact area, the prestress applied by the torque nut 2 can be evenly dispersed to the surface of the surrounding rock, avoiding damage to the surrounding rock caused by excessive local stress, so that the prestress can be more effectively transmitted to the anchoring area, and the stability and reliability of the anchoring are enhanced. Therefore, the tray 4 is arranged away from the first threaded end, which can play a role in transmitting and diffusing the prestress. On the other hand, the tray 4 can increase the integrity and strength of the surrounding rock by being in close contact with the surrounding rock. When subjected to external loads or geological stresses, the tray 4 can effectively prevent the displacement and deformation of the surrounding rock, provide a stable support foundation for the anchor, and thus ensure the long-term effectiveness of the anchoring system. Therefore, the tray 4 can play a role in reinforcing the surrounding rock and preventing displacement.

[0033] In order to ensure sufficient contact between the torque nut 2 and the tray 4, a gasket 3 may be provided between the torque nut 2 and the tray 4. In some embodiments, the gasket 3 may be made of a highly elastic rubber material or a polymer material with similar properties. It has a certain thickness and a suitable elastic coefficient, and when placed between the torque nut 2 and the tray 4, it can form a flexible connection layer between the two. When the torque nut 2 is tightened, the elastic buffer gasket 3 can automatically deform elastically according to the surface flatness and pressure distribution between the torque nut 2 and the tray 4, filling the tiny gaps and uneven areas that may exist between the two, thereby ensuring an all-round tight fit between the torque nut 2 and the tray 4.

[0034] Considering that the contact surface between the torque nut 2 and the tray 4 is fully fitted, in the embodiment provided by the present invention, the gasket 3 is determined to be a spherical gasket 3. The special spherical structure of the spherical gasket 3 enables it to adaptively adjust the relative position relationship between the torque nut 2 and the tray 4 within a certain angle range. Even when there is a slight angle deviation between the components during the installation process or due to external forces, it can ensure the tight connection between the two through its own deformation, effectively reducing the stress concentration and energy loss caused by loose connection. Therefore, the spherical gasket 3 can be used to ensure that the contact surface between the torque nut 2 and the tray 4 is fully fitted, thereby improving the connection quality.

[0035] In actual application scenarios, after the anchor rod is installed in the hole, it may be affected by the external force of the hole wall and cause the anchor rod to close improperly. In order to prevent the anchor rod from being squeezed and closed by the hole wall, thereby affecting its normal working performance and service life, and at the same time to enhance the full-length anchoring to achieve a more reliable fixing effect, a sleeve 6 with a certain strength and suitable structure can also be tightly mounted on the outside of the anchor rod body 1. The sleeve 6 can cooperate well with the anchor rod body 1 and the surrounding anchoring environment to jointly construct a stable anchoring system.

[0036] On this basis, the sleeve 6 has a first connecting end, which is an end close to the second threaded end, and is connected to the connecting end of the expansion wedge 8 through the first connecting end.

[0037] Due to the existence of the sleeve 6, it can not only play a certain protective role on the anchor body 1, reduce the erosion and wear of the anchor body 1 by the external environment such as soil, sand, and water during installation and use, and extend the service life of the anchor. And through its connection with the expansion wedge 8 and its position relationship on the anchor body 1, the force generated during the anchoring process can be effectively transmitted and dispersed between the anchor body 1 and the expansion wedge 8. When the anchor is subjected to external force, the sleeve 6 can evenly transmit the force to the entire anchoring system to avoid structural damage caused by excessive local force.

[0038] In addition, the presence of the sleeve 6 not only provides a clear installation reference and guide for the installation of the anchor rod, but also limits the movement range of the expansion wedge 8, ensuring that the expansion wedge 8 can be expanded and maintained in a stable state according to the design requirements during the anchoring process, thereby enhancing the anchoring effect and stability of the entire anchor rod.

[0039] The present invention does not impose any specific restrictions on the connection method between the first connection end and the expansion wedge 8. For example, in some embodiments, mechanical connection such as threaded connection, pin connection, etc., or welding can be used. In the exemplary embodiment provided by the present invention, in order to ensure the reliability and sealing of the connection, the present invention sets the connection between the first connection end and the expansion wedge 8 by ring pressing.

[0040] Compared with the common connection method, the ring pressure connection method can not only withstand greater external forces such as tension and shear force, but also make the connection between the first connection end and the connection end of the expansion wedge 8 more firmly, and it is not easy to loosen during the operation of the anchor rod, thus ensuring the structural integrity of the entire anchor rod system when under stress. It can also form a good sealing effect at the connection part, preventing external dust, moisture, impurities, etc. from entering the connection part, thereby effectively avoiding corrosion and damage to the connection part, and at the same time it is also beneficial to maintain the stability of the anchor rod connection performance in some special environments (such as underwater, humid underground environments, etc.). In addition, due to the uniform pressure distribution characteristics of the ring pressure connection, the force transmitted from the sleeve 6 to the expansion wedge 8 or from the expansion wedge 8 back to the sleeve 6 can be more evenly distributed on the connection interface, reducing stress concentration, and improving the force transmission efficiency, so as to better play the anchoring role of the entire anchor rod system.

[0041] During the installation and use of the anchor rod, due to the influence of various external forces and vibrations, the sleeve 6 may have a tendency to slide axially along the anchor rod body 1. In order to limit the axial movement and deformation of the sleeve 6 on the anchor rod body 1, some limiting structures can be provided on the sleeve 6 or the anchor rod body 1 to limit the sleeve 6. For example, in some embodiments, a protrusion can be provided at the end of the sleeve 6 or an annular groove can be machined on the anchor rod body 1 at a position corresponding to the sleeve 6. However, considering the structural stability, in the exemplary embodiment provided by the present invention, the sleeve 6 also has a second connecting end, which is an end close to the first threaded end; the combined prestressed anchor rod also includes a sleeve clamp 5, which is sleeved on the second connecting end.

[0042] In this way, the existence of the sleeve clamping ring 5 can provide a restriction at the end of the sleeve 6, ensuring that the sleeve 6 always remains in the designed position, thereby ensuring the stability of the entire anchoring system. And through the clamping effect of the sleeve clamping ring 5 on the sleeve 6, the connection between the sleeve 6 and the anchor body 1 can be made more secure, and the tightness of the connection between the sleeve 6 and the anchor body 1 near the second connection end is increased, thereby effectively reducing the relative rotation or looseness that may occur between the two, which is conducive to the effective transmission of force and the realization of the anchoring effect.

[0043] On this basis, considering that the radial movement of the anchor body 1 inside the sleeve 6 may also affect the anchoring effect and system stability, therefore, in some embodiments, an annular rubber lining may be provided on the inner wall of the sleeve 6, or some tiny pits or patterns may be processed on the inner wall of the sleeve 6 to increase the friction resistance between the inner wall of the sleeve 6 and the anchor body 1, so as to prevent the anchor body 1 from radially sliding in the sleeve 6. However, considering the stability and service life of the anchor structure, in the exemplary embodiment provided by the present invention, a limiting ring 7 is provided on the inner wall of the sleeve 6, and the limiting ring 7 is provided in the middle position inside the sleeve 6, which can not only limit the installation position of the anchor body 1 (i.e., limit the anchor body 1 to the center position), but also limit its radial movement.

[0044] The limiting ring 7 is usually made of a material with certain strength and rigidity, and its structure is relatively stable and not easily deformed due to long-term use or certain external force impact, so it can meet the requirements of structural stability and service life.

[0045] According to another aspect of the present invention, referring to Figure 3 As shown, a method for anchoring a combined prestressed anchor rod is also provided, and the anchoring construction method comprises: S1: Drill anchor holes on the working surface; S2: Push the combined prestressed anchor into the anchor hole to achieve full-length anchoring; S3: Turn the torque nut 2. When the combined anchor head 9 is embedded in the expansion wedge 8 and the expansion wedge 8 is fully squeezed open, continue to turn the torque nut 2 until the first thread end stops moving, and the anchoring is completed.

[0046] In S1, anchor holes are drilled on the working surface.

[0047] The present invention does not limit the method of drilling the anchor hole. For example, in some embodiments, the hole can be drilled using an anchor drill, or a down-the-hole drill or a handheld pneumatic rock drill. Those skilled in the art can selectively use the above drilling tools according to actual conditions.

[0048] When drilling the anchor hole, it should be noted that the anchor hole diameter must be smaller than the diameter of the sleeve 6 before closing. In this way, it can be ensured that the sleeve 6 can pass smoothly before being installed into the anchor hole. If the anchor hole diameter is larger than the diameter of the sleeve 6 before closing, the sleeve 6 cannot be closed during the insertion process of the anchor hole, which will produce radial pressure on the hole wall, thereby causing the full-length anchoring to fail. Obviously, when the anchor hole diameter is smaller than the diameter of the sleeve 6 before closing, after the sleeve 6 is placed in the anchor hole, with the subsequent installation operation, the sleeve 6 can fit tightly on the anchor hole wall. In this way, the friction and bite force between the sleeve 6 and the anchor hole wall can be increased, and the stability of the entire anchoring system can be improved. During the anchoring process, the anchoring force can be better transmitted and dispersed, avoiding uneven distribution of the anchoring force due to the excessive gap between the sleeve 6 and the anchor hole wall, which affects the anchoring effect.

[0049] In S2, the combined prestressed anchor rod is pushed into the anchor rod hole to achieve full-length anchoring.

[0050] Figure 4 It is a schematic diagram of the working principle of the sleeve, which shows the mechanism of full-length mechanical anchoring of the combined prestressed anchor rod: the combined anchor rod is inserted as a whole into the pre-drilled anchor rod hole. Since the anchor rod hole diameter is slightly smaller than the diameter of the sleeve 6, the outer tube wall of the sleeve 6 will be squeezed by the hole wall, causing the sleeve 6 to close radially. At the same time, the hole wall will be subject to the radial force of the sleeve 6 itself that hinders the closure, thereby generating a friction anchoring force along the hole wall direction, thereby achieving full-length anchoring.

[0051] When pushing the combined prestressed anchor provided by the present invention into the anchor hole, it should be noted that the staff should hold the first threaded end, align the second threaded end with the expansion wedge 8 with the entrance of the anchor hole, keep the axis of the anchor substantially coincident with the axis of the anchor hole, and then push the combined prestressed anchor into the anchor hole steadily and forcefully. During the pushing process, the advancement of the combined prestressed anchor should be observed at all times to ensure that it is not obstructed or stuck.

[0052] After the combined prestressed anchor rod is completely pushed into the anchor rod hole, check whether the position of the combined prestressed anchor rod in the hole meets the requirements, and check whether the tray 4 fits tightly against the surface of the surrounding rock. If there is a gap between the tray 4 and the surrounding rock, it is necessary to properly adjust the position of the tray 4 or fill it with a gasket 3 or the like to ensure that the tray 4 can effectively transfer and diffuse the prestress.

[0053] In S3, the torque nut 2 is rotated, and when the combined anchor head 9 is embedded in the expansion wedge 8 and the expansion wedge 8 is fully squeezed open, the torque nut 2 is continuously rotated until the first thread end stops moving, thereby completing the anchoring.

[0054] As the torque nut 2 rotates, the anchor rod drives the combined anchor head 9 and the expansion wedge 8 to produce relative displacement, squeezes the expansion wedge 8 to achieve the end expansion effect, and squeezes the anchor rod hole wall to achieve preliminary anchoring of the end.

[0055] On this basis, continue to rotate the torque nut 2. Based on the special design of the anchor head end, when the end of the expansion wedge 8 is squeezed into the anti-overslip buckle at the end of the anchor head, it is resisted and the anchor rod end no longer moves. Continue to rotate the torque nut 2, which is equivalent to fixing one end and continuing to stretch the other end. This process realizes the application of prestress.

[0056] The expansion direction of the expansion wedge 8 is mainly along the radial direction of the anchor hole, exerting pressure on the surrounding surrounding rock. As the expansion wedge 8 continues to expand, the contact area between it and the anchor hole wall and the surrounding surrounding rock gradually increases, and the friction and extrusion forces also increase accordingly. The friction and extrusion forces together constitute the anchoring force. When the expansion wedge 8 is fully squeezed open, the anchoring force reaches a level that can firmly fix the anchor in the surrounding rock. At this time, a stable anchoring system is formed between the anchor, the expansion wedge 8 and the surrounding rock. In this system, the anchor transfers the prestress to the surrounding rock through the expansion wedge 8, and the surrounding rock supports the anchor through the reaction force on the expansion wedge 8, thereby achieving the anchoring of the anchor.

[0057] Figure 5 The schematic diagram of the working principle of the expansion wedge 8 shows the mechanism of mechanical anchoring of the combined prestressed anchor bolt end: the combined anchor head 9 is embedded in the open end below the expansion wedge 8 and is tightly connected to the second threaded end through threads. During the process of applying prestress, the anchor bolt body 1 moves upward, which will drive the combined anchor head 9 to move upward synchronously, so that it is further embedded in the expansion wedge 8. After the combined anchor head 9 moves upward to a certain distance, it will stop moving upward due to the obstruction of the anti-overslip buckle at its end to prevent it from being overly embedded in the expansion wedge 8. At this time, the expansion wedge 8 is fully opened to apply the end anchoring force to the surrounding hole wall.

[0058] refer to Figure 6 As shown, the more explicit steps are: First, the anchor hole is punched on the working surface, and the anchor is pushed into the anchor hole as a whole. The sleeve 6 is squeezed and closed, generating radial force on the hole wall, forming friction anchoring force, achieving full-length anchoring, and completing the first step of mechanical anchoring. Then, the torque nut 2 is turned to apply prestress to the anchor, and at the same time, the combined anchor head 9 moves upward and continues to be embedded in the expansion wedge 8. After moving upward to a certain position, it is stuck. At this time, the expansion wedge 8 has been fully squeezed open, and the end of the anchor is expanded to achieve end anchoring, and finally the second step of mechanical anchoring and the prestressing process are completed.

[0059] Therefore, when the first step of mechanical anchoring is performed, the sleeve 6 is squeezed and closed to generate radial force on the hole wall, so that the connection between the anchor rod and the hole wall is tighter. On the one hand, this tight connection increases the friction between the two, so that the friction anchoring force formed can effectively resist various external forces such as tension and shear force that the anchor rod is subjected to during operation, greatly improving the stability of anchoring; on the other hand, by squeezing the sleeve 6 to form the friction anchoring force, for the anchor rod hole wall under different geological conditions (whether it is hard rock or soft rock formation), the degree of squeezing of the sleeve 6 and the size of the radial force can be adjusted to achieve a reliable anchoring effect, thereby improving the application scope of the anchoring technology in various complex geological environments. And the realization of full-length anchoring means that the anchor rod forms an effective connection and anchoring effect with the surrounding medium (such as the hole wall) throughout its entire length. Compared with the traditional local anchoring method, it can better disperse and withstand loads from different directions, reducing the risk of anchor failure due to excessive local force.

[0060] In the second step of mechanical anchoring, the torque nut 2 is rotated to apply prestress to the anchor rod, so that the anchor rod is in a pre-tensioned state. This prestress can offset part of the possible tension in advance when the anchor rod is working, thereby improving the bearing capacity of the anchor rod. At the same time, the combined anchor head 9 continues to embed the expansion wedge 8 and fully squeezes the expansion wedge 8, realizing the end anchoring, further increasing the anchoring force of the anchor rod end, and making the anchoring effect of the entire anchor rod more reliable.

[0061] The combination of end anchoring and full-length anchoring forms a double anchoring mechanism, which achieves strong fixation from the whole to the part, greatly improving the pull-out resistance and stability of the anchor rod.

[0062] The application of prestress can make the anchor rod in a tight state before working, which can effectively reduce the deformation and displacement of the surrounding rock or structure when subjected to external forces. Especially in some projects with strict requirements on deformation, such as tunnels and underground projects, it can effectively control the convergence and deformation of the surrounding rock and ensure the stability and safety of the engineering structure.

[0063] The double anchoring mechanism and prestressing can reduce the loosening and fatigue damage of anchor rods during long-term use, thus extending the service life of anchor rods. At the same time, good anchoring effect can also reduce the maintenance and replacement work caused by anchor rod failure, thus reducing the maintenance cost of the project.

[0064] It should be understood that the present invention does not limit its application to the detailed structure and arrangement of the components proposed by the present invention. The present invention can have other embodiments and can be implemented and executed in a variety of ways. The aforementioned variations and modifications fall within the scope of the present invention. It should be understood that the present invention disclosed and defined by the present invention extends to all alternative combinations of two or more individual features mentioned or evident in the text and / or the accompanying drawings. All these different combinations constitute multiple alternative aspects of the present invention. The embodiments described in the present invention illustrate the best mode known for implementing the present invention and will enable those skilled in the art to utilize the present invention.

Claims

1. A combined prestressed anchor rod, characterized in that: include: An anchor body having a first threaded end and a second threaded end disposed opposite to each other; A sleeve, sleeved on the anchor body; A pre-tightening assembly, disposed on the first threaded end, for threadably cooperating with the first threaded end during anchoring to pre-tighten the anchor rod body and change the position of the second threaded end; A combined anchor head, threadedly connected to the second threaded end; The expansion wedge body has an open end, and the combined anchor head can extend into the expansion wedge body through the open end under the action of pre-tightening to expand the expansion wedge body and realize anchoring.

2. The combined prestressed anchor rod according to claim 1, characterized in that: The sleeve has a first connecting end; Wherein, the first connecting end is an end close to the second threaded end, and the first connecting end is connected to the connecting end of the expansion wedge.

3. The combined prestressed anchor rod according to claim 2, characterized in that: The first connecting end is connected to the connecting end of the expansion wedge in a ring pressing manner.

4. The combined prestressed anchor rod according to claim 2, characterized in that: The sleeve also has a second connecting end, which is an end close to the first threaded end; The combined prestressed anchor rod also includes a sleeve clamping ring, and the sleeve clamping ring is sleeved on the second connecting end.

5. The combined prestressed anchor rod according to claim 4, characterized in that: The combined prestressed anchor rod further comprises a limiting ring, which is arranged at a middle position inside the sleeve to limit the installation position and movement position of the anchor rod body.

6. The combined prestressed anchor rod according to any one of claims 1 to 4, characterized in that: The preload assembly comprises: A torque nut, wherein the internal thread in the torque nut is threadably matched with the external thread of the first threaded end.

7. The combined prestressed anchor rod according to claim 6, characterized in that: The preload assembly also includes: A tray is sleeved on the anchor rod body and is arranged away from the first threaded end. A gasket is sleeved on the anchor rod body and located between the tray and the torque nut.

8. The combined prestressed anchor rod according to claim 7, characterized in that: The gasket is a spherical gasket.

9. An anchoring construction method of a combined prestressed anchor rod according to any one of claims 1 to 8, characterized in that: The anchoring construction method comprises: S1: Drill anchor holes on the working surface; S2: Pushing the combined prestressed anchor rod into the anchor rod hole to achieve full-length anchoring; S3: Turn the torque nut. When the combined anchor head is embedded in the expansion wedge and the expansion wedge is fully squeezed open, continue to turn the torque nut until the first thread end stops moving, thereby completing the end anchoring.

10. The anchoring construction method according to claim 9, characterized in that: The diameter of the anchor hole is smaller than the diameter of the sleeve before closing.

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