Screw-in self-locking type combined hollow anchor rod system and construction method

Abstract

The invention provides a screw-in self-locking type combined hollow anchor rod system and a construction method, relates to the field of anchor rod systems, and aims to solve the problem that an existing forward-pushing expansion shell type anchor rod is poor in anti-pulling capacity, a positioning section and an extrusion section are arranged at the tail end of a threaded rod body, and the extrusion section can extend into a variable-diameter section, so that the variable-diameter section can be expanded for anchoring; a telescopic positioning pin is arranged on the positioning section and can extend into a clamping groove formed in the anchor crown in the radial direction when being matched with the anchor crown to form a one-way stop structure, so that the pulling resistance of the anchor crown after being matched with the anchor crown is improved, and a guarantee is provided for applying high prestress in the later period; the problem that initial pulling force cannot be effectively applied due to low early-stage strength of the anchor rod due to the fact that traditional mechanical anchoring only depends on thread friction or only an early-strength anchoring agent is used for providing the tensile capacity is solved.

Description

Technical Field

[0001] The invention relates to the field of anchor rod systems, and in particular to a screw-in self-locking combined hollow anchor rod system and a construction method. Background Art

[0002] In tunnel engineering, the initial support construction mostly adopts sprayed anchor support structure, among which the widely used sprayed anchor support types include anchor shotcrete support, anchor shotcrete steel arch support and anchor shotcrete steel mesh support. Ordinary mortar anchors often adopt the process of grouting first and then inserting reinforcement. Human factors have a great influence on the grouting fullness, especially in the arch with large elevation angle, the grouting fullness is more difficult to ensure, and there is currently a lack of effective methods to test the mortar fullness, resulting in pores, cavities and exposed steel bars in the borehole. It is often difficult to avoid, which seriously affects the durability of the anchor. In addition, due to the deadweight of the anchor and the fluidity of the mortar, the anchor in the borehole will actively lean against and cling to one side of the hole wall, and the thickness of the mortar protective layer cannot be guaranteed. The outer side of the hollow grouting anchor is a standard large pitch thread. The thread structure is convenient for the cutting and extension of the anchor. Compared with the smooth rod body, it increases the bonding area between the anchor body and the grouting material, thereby improving the anchoring force. The hole in the anchor rod body is used to drill the high-pressure wind and water channel and the grouting channel. Its rigidity and shear strength are also better than the solid rod body. However, sometimes in order to improve the grouting effect, small holes are drilled on the surface of the rod body, which will reduce the strength of the rod body. Ordinary mortar anchor rods and ordinary grouting anchor rods are passive support anchor rods. When drilling holes in poor formations such as weak and broken rock, the hole often collapses after the drill rod is pulled out, and the formation has poor coping ability.

[0003] A Chinese patent (publication number CN 116877159 A, publication date 20231013) discloses an expansion shell type combined anchor system and construction method, wherein one end of the anchor body is connected to the anchor head assembly through a connecting sleeve, and the other end of the anchor is used to extend to the outside of the surrounding rock and connect to the anchor assembly, the anchor head assembly includes a rod body, one end of the rod body is connected to the connecting sleeve, and the other end is threadedly connected to an expansion anchor crown, the expansion anchor crown includes a fixed part and a plurality of expansion parts arranged at the end of the fixed part, the fixed part is threadedly connected to the rod body through a threaded through hole, and the rod body extends into the space between the plurality of expansion parts to open the plurality of expansion parts; after the expansion parts are opened and anchored in the borehole, the anchor crown part located between adjacent expansion parts is not fully squeezed, and the pull-out resistance of the expansion parts is poor, especially when the anchor rod has low strength in the early stage and cannot effectively apply the initial tension. Summary of the invention

[0004] The purpose of the present invention is to provide a screw-in self-locking combined hollow anchor system and a construction method in response to the defects of the prior art. A positioning section and an extrusion section are arranged at the end of the threaded rod body. The extrusion section can penetrate into the diameter-changing section so that the diameter-changing section can expand and anchor, thereby ensuring the anchoring effect of the anchor crown and the drill hole. A retractable positioning pin is arranged on the positioning section. The positioning pin can radially penetrate into a groove provided in the anchor crown when cooperating with the anchor crown to form a one-way stop structure, thereby improving the pull-out resistance after cooperating with the anchor crown, providing a guarantee for applying high prestress in the later stage, and avoiding the problem that the traditional mechanical anchoring relies solely on thread friction or only uses early-strength anchoring agents to provide tensile resistance, resulting in low initial strength of the anchor rod and inability to effectively apply initial tension.

[0005] The first object of the present invention is to provide a screw-in self-locking combined hollow anchor system, which adopts the following scheme: include: The hollow anchor rod body is equipped with an anchor; The end of the threaded rod body is butted with the end of the hollow anchor rod body. The threaded rod body is provided with a positioning section and an extrusion section. The positioning section is provided with a positioning needle that can be extended and retracted in the radial direction. Along the axial direction of the threaded rod body, an inclined guide surface is provided on the side of the positioning needle away from the hollow anchor rod body to receive the thrust to retract the positioning needle into the threaded rod body. The anchor crown is a cylindrical structure with a guide hole, a through hole and a reducing hole distributed in sequence along the axial direction. The guide hole is an internal threaded hole with an inner wall provided with a thread matching the outer thread of the threaded rod. The inner wall of the through hole is provided with a slot for a one-way locking positioning pin. The reducing hole gradually reduces in diameter in the direction away from the hollow anchor rod body to accommodate the extrusion section.

[0006] Furthermore, the positioning needles are provided in a plurality of groups, and the plurality of groups of positioning needles are spaced apart and distributed along the axis of the threaded rod body, and each group of positioning needles is provided with two positioning needles, and the two positioning needles in the same group abut against the resilient member together.

[0007] Furthermore, there are multiple slots along the axial direction of the anchor crown, and the multiple slots are distributed corresponding to the multiple groups of positioning pins. The positioning pins accompany the movement of the threaded rod relative to the anchor crown to pass through other slots and then reach the slot corresponding to the positioning pin, thereby one-way stopping the relative movement of the threaded rod and the anchor crown.

[0008] Furthermore, along the axial direction of the threaded rod body away from the hollow anchor rod body, the lengths of the multiple groups of positioning pins protruding out of the outer periphery of the threaded rod body gradually increase, and the corresponding groove depth gradually increases.

[0009] Furthermore, the extrusion section is distributed closer to the end of the threaded rod body than the positioning section, and the end of the threaded rod body is an end away from the hollow anchor rod body. The extrusion section passes through the guide hole and the through hole in sequence and then enters the variable diameter hole.

[0010] Furthermore, the outer peripheral wall of the anchor crown is provided with concave and convex patterns distributed alternately, and the anchor crown is coaxially matched with the threaded rod body.

[0011] Furthermore, the anchor comprises a pad and a nut. The pad is sleeved outside the hollow anchor body, one side of the pad abuts against the slurry stopper, and the other side abuts against the nut. An exhaust hole is opened on the pad, and the nut cooperates with the threaded section of the hollow anchor body.

[0012] Furthermore, the hollow anchor rod body and the threaded rod body are butt-jointed via a connecting sleeve, the connecting sleeve is externally mounted on a positioner, a slurry outlet hole is provided on the connecting sleeve, and the hollow anchor rod body is connected to the slurry outlet hole.

[0013] The second object of the present invention is to provide a construction method of the screw-in self-locking combined hollow anchor system as described in the first object, comprising: Assemble the hollow anchor rod body and the threaded rod body, and pre-assemble the anchor crown and the threaded rod body; The anchor crown is placed into the borehole using the hollow anchor rod body and the threaded rod body, the extrusion section is kept separated from the variable diameter hole, and the anchor crown corresponding to the variable diameter hole is in an unexpanded state until the anchor crown reaches the bottom of the borehole; Rotating the hollow anchor rod body drives the threaded rod body to rotate in coordination with the guide hole, so that the positioning section and the extrusion section of the threaded rod body are pushed into the interior of the anchor crown; The positioning pin passes through other slots and then enters the slot it matches, preventing the threaded rod from coming out of the anchor crown; the extrusion section gradually enters the variable diameter hole, causing the anchor crown area corresponding to the variable diameter hole to expand and fill densely for anchoring; Anchors are installed on the hollow anchor rod body and prestress is applied, and grouting is performed on the drilled hole.

[0014] Furthermore, as the threaded rod moves along the inside of the anchor crown, the positioning pin first penetrates into the slot when passing through the slot, and then as the threaded rod moves further, the guide surface is forced to push the positioning pin back into the threaded rod to pass through the slot to reach the next slot.

[0015] Compared with the prior art, the present invention has the following advantages and positive effects: In view of the problem that the current forward-push expansion shell type anchor has poor pull-out resistance, a positioning section and an extrusion section are provided at the end of the threaded rod body. The extrusion section can penetrate into the reducing section so that the reducing section can expand and anchor, thereby ensuring the anchoring effect of the anchor crown and the drill hole. A retractable positioning pin is provided on the positioning section. When matching with the anchor crown, the positioning pin can radially penetrate into the groove provided in the anchor crown to form a one-way stop structure, thereby improving the pull-out resistance after matching with the anchor crown, providing a guarantee for the subsequent application of high prestress, and avoiding the problem that traditional mechanical anchoring relies solely on thread friction or only uses early-strength anchoring agents to provide tensile resistance, resulting in low initial strength of the anchor rod and inability to effectively apply initial tension.

[0016] A guide hole, a through hole and a reducing hole are respectively arranged along the axial direction of the threaded rod body to be matched with the anchor crown. The guide hole is an internal threaded hole that matches the external thread distributed on the threaded rod body, and the internal threaded hole guides the direction of the threaded rod body; the through hole is for the threaded rod body to pass through, and a groove is opened radially outward on the inner wall of the through hole, so that the slidably matched positioning pin on the threaded rod body can be inserted into the groove to form an anti-pullout structure, thereby restricting the displacement of the threaded rod body from the direction of the anchor crown; the reducing hole is for the threaded rod body to pass through, and when the end of the threaded rod body gradually enters the reducing hole, the threaded rod body squeezes and pushes the anchor crown, so that the segments of the reducing holes distributed on the anchor crown can expand radially outward, thereby squeezing the drilled hole to improve the anchoring effect, so that the threaded rod body connected to the hollow anchor rod body can be stably anchored in the drilled hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0018] Figure 1 It is a schematic diagram of a screw-in self-locking combined hollow anchor system in one or more embodiments of the present invention.

[0019] Figure 2 Schematic diagram of a nut in one or more embodiments of the present invention.

[0020] Figure 3 Schematic diagram of a pad in one or more embodiments of the present invention.

[0021] Figure 4 Schematic diagram of the distribution of exhaust holes on the pad in one or more embodiments of the present invention.

[0022] Figure 5 It is a schematic diagram of the distribution of positioning pins on the threaded rod body in one or more embodiments of the present invention.

[0023] Figure 6 Schematic diagram of an anchoring crown in one or more embodiments of the present invention.

[0024] Among them, 1. nut; 2. washer; 3. pad; 4. exhaust hole; 5. slurry stop plug; 6. hollow anchor rod body; 7. exhaust pipe; 8. slurry outlet hole; 9. connecting sleeve; 10. positioner; 11. threaded rod body; 12. anchor crown; 13. positioning pin; 14. anchor arm through hole; 15. nut slot; 16. annular steel ring on the outer side of the pad; 17. curved protrusion; 18. annular steel ring on the inner side of the pad; 19. high-elastic spring; 20. semi-curved steel sheet; 21. slot; 22. texture. DETAILED DESCRIPTION

[0025] Example 1 In a typical embodiment of the present invention, Figure 1-Figure 6As shown, a screw-in self-locking combined hollow anchor system is provided.

[0026] In the current anchor system, the pull-out resistance of the anchor is poor, and there is a problem that the anchor strength is low in the early stage and the initial tension cannot be effectively applied. Based on this, this embodiment provides a screw-in self-locking combined hollow anchor system, which rotates and pushes the threaded rod 11 so that the positioning pin 13 at the end of the threaded rod 11 is ejected into the corresponding slot 21 of the semi-expanded cylindrical anchor crown 12, so that the anchor crown 12 is tightly fitted with the surrounding rock to provide a larger anchoring force, thereby solving the problem that the anchor strength is low in the early stage and the initial tension cannot be effectively applied.

[0027] like Figure 1 As shown, the screw-in self-locking combined hollow anchor system mainly includes a hollow anchor body 6, a threaded rod body 11 and an anchor crown 12. The end of the threaded rod body 11 is connected to the end of the hollow anchor body 6 through a connecting sleeve 9. The main body of the anchor system is composed of the threaded rod body 11, the hollow anchor body 6 and the connecting sleeve 9. The length of the threaded rod body 11 and the hollow anchor body 6 is determined by the anchor design. It inherits the convenience of the hollow grouting anchor, the prestressing can be applied immediately, and the anchor body has good comprehensive mechanical properties.

[0028] The threaded rod body 11 is provided with a positioning section and an extrusion section. The positioning section is provided with a radially retractable positioning needle 13. Along the axial direction of the threaded rod body 11, an inclined guide surface is provided on the side of the positioning needle 13 away from the hollow anchor rod body 6 to receive the thrust to retract the positioning needle 13 into the threaded rod body 11.

[0029] The anchor crown 12 is a cylindrical structure as a whole, and is provided with guide holes, through holes and diameter-reducing holes distributed in sequence along the axial direction. Among them, two semi-curved steel sheets 20 are fixed at one end of the anchor crown 12. The two semi-curved steel sheets 20 are symmetrical, and a diameter-reducing hole is formed between them. The diameter of the diameter-reducing hole gradually decreases in the direction away from the hollow anchor rod body 6 to accommodate the extrusion section. The two steel sheets and the extrusion section of the threaded rod body 11 form a squeeze action during the insertion process to achieve an expansion effect, which is similar to an expansion screw. The other end of the anchor crown 12 is cylindrical, and there are multiple protrusions parallel to the end face of the anchor crown 12 on the outside, forming a texture 22 to increase the bonding friction with the rock mass. A communicating guide hole and through hole are formed on the inside, and a slot 21 is provided on the inner wall of the through hole. The slot 21 can unidirectionally engage the positioning pin 13.

[0030] In this embodiment, the guide hole is an internal threaded hole with an inner wall provided with an external thread matching the threaded rod 11. The threaded rod 11 can be pushed axially relative to the guide hole through the relative rotation of the threaded rod 11 and the guide hole. The steel sheet has a certain thickness and plasticity, and the inner surface of the steel sheet gradually approaches the central axis of the threaded rod 11 to form a variable diameter hole, so that the steel sheet can expand and open after the threaded rod 11 is pushed.

[0031] There are multiple groups of positioning pins 13, which are spaced apart along the axial direction of the threaded rod 11. Each group of positioning pins 13 has two positioning pins, and the two positioning pins 13 in the same group abut against the resilient member. Correspondingly, there are multiple slots 21 along the axial direction of the anchor crown 12, and the multiple slots 21 are distributed corresponding to the multiple groups of positioning pins 13. The positioning pins 13 follow the movement of the threaded rod 11 relative to the anchor crown 12 to pass over other slots 21 and then reach the slot 21 corresponding to the positioning pin 13, thereby unidirectionally stopping the relative movement of the threaded rod 11 and the anchor crown 12.

[0032] In this embodiment, there are three groups of positioning pins 13, and three layers of slots 21. The slots 21 are annular slots with a wedge-shaped cross section. The radial depth of each layer of slots 21 increases in sequence in the direction away from the threaded rod 11. The positioning pins 13 of the threaded rod 11 are rotated and pushed into the slots 21 of the anchor crown 12 to achieve the fixation of the end of the threaded rod 11 and the anchor crown 12. At the same time, the extrusion section at the end of the threaded rod 11 is squeezed into the variable diameter hole, so that the end of the anchor crown 12 is squeezed tightly with the rock mass to achieve the anchoring effect.

[0033] like Figure 6 As shown, the anchor crown 12 is divided into three functional sections along the axial direction of the threaded rod 11, namely, a guiding section, a clamping section and an expansion section. The guiding section is provided with an internal threaded hole that matches the external thread distributed on the threaded rod 11, and the internal threaded hole serves as a guiding hole for guiding the threaded rod 11; the clamping section is provided with a through hole for the threaded rod 11 to pass through, and the inner wall of the through hole is provided with a clamping groove 21 radially outward, so that the slidably matched positioning pin 13 on the threaded rod 11 can be inserted into the clamping groove 21 to form an anti-pullout structure, thereby restricting the displacement of the threaded rod 11 from the anchor crown 12; the expansion section is provided with a reducing hole for the threaded rod 11 to pass through, and when the end of the threaded rod 11 gradually penetrates into the reducing hole, the threaded rod 11 squeezes and pushes the anchor crown 12, so that the expansion section of the anchor crown 12 can expand radially outward, thereby squeezing the drilled hole to improve the anchoring effect, so that the threaded rod 11 connected to the hollow anchor body 6 can be stably anchored in the drilled hole.

[0034] like Figure 5 and Figure 6 As shown, three layers of vertically crossed anchor arm through holes 14 are provided on the positioning section at one end of the threaded rod body 11, and a group of positioning pins 13 symmetrically distributed relative to the axis of the threaded rod body 11 are installed in each group of anchor arm through holes 14. The positioning pins 13 are slidably matched with the anchor arm through holes 14 set on the threaded rod body 11, and the aperture sizes of the two are matched.

[0035] Each group of positioning pins 13 includes two positioning pins 13, and the two positioning pins 13 in the same group are coaxially arranged at intervals, and a resilient member is provided between the two positioning pins 13 in the same group, and the two ends of the resilient member respectively abut against the positioning pins 13 to accept the compression of the positioning pins 13 or rebound to drive the positioning pins 13 to slide relative to the anchor arm through hole 14. In this embodiment, the resilient member adopts a high-elasticity spring 19, and the sum of the maximum compression amount of the high-elasticity spring 19 and the length of the positioning pins 13 on both sides is less than or equal to the diameter length of the threaded rod body 11, so that the positioning pins 13 can be completely retracted into the threaded rod body 11, and the elasticity of the high-elasticity spring 19 meets the fixing requirements of the positioning pins 13, and the strength is set according to the anchoring force design of the anchor rod system.

[0036] An inclined guide surface is provided on the side of the positioning pin 13 away from the hollow anchor rod body 6. When the positioning pin 13 moves relative to the anchor crown 12, the inclined guide surface of the positioning pin 13 can receive the thrust of the anchor crown 12, so that the positioning pin 13 is retracted into the threaded rod body 11, and then pops out and probes into the slot 21 when it reaches the next slot 21. The shape of one end of the inclined guide surface is consistent with the shape of the wedge-shaped slot 21 of the anchor crown 12, so that after the positioning pin 13 enters the slot 21, when the threaded rod body 11 continues to rotate and advances axially, the inclined guide surface of the positioning pin 13 can contact the wedge-shaped inclined surface of the slot 21, receive the thrust, and gradually retract into the anchor arm through hole 14.

[0037] Specifically, the slot 21 is distributed circumferentially on the inner wall of the through hole corresponding to the anchor crown 12, and the axial cross-section is wedge-shaped. The three layers of positioning pins 13 distributed on the positioning section of the threaded rod body 11 are vertically staggered in space, and the end of the positioning pin 13 is also wedge-shaped by setting an inclined guide surface. When one end of the threaded rod body 11 is screwed into the anchor crown 12, due to the presence of a high-elasticity spring 19 in the middle of the positioning pin 13, the inclined guide surface at the end of the positioning pin 13 can slide on the inclined surface of the slot 21, and is unidirectional. Along the direction of axial movement of the threaded rod body 11 relative to the anchor crown 12, the positioning pin 13 is locked after each layer of the slot 21 is inserted. Due to the restraining effect of the wedge-shaped structure, the positioning pin 13 restrains the reverse movement of the threaded rod body 11 relative to the axial movement of the anchor crown 12. After the threaded rod body 11 is inserted into the anchor crown 12, it moves unidirectionally until the three layers of positioning pins 13 are correspondingly inserted into the corresponding positions of the three layers of the slot 21, and the screwing-in process of the threaded rod body 11 is completed. During this process, the semi-curved steel sheet 20 expands radially and adheres to the drilled rock wall due to the screwing-in thrust of the threaded rod body 11.

[0038] The structures of the lines 22 and the three-layer expansion grooves 21 are to increase the friction and connection force of the threaded rod 11 to strengthen the anchoring effect and restrict the threaded rod 11 from being pulled out. The anchor crown 12 is rotated and pushed into the lock to generate support force immediately. The local point anchoring method clamps the rock mass immediately to form a pressure arch and inhibit the development of the surrounding rock loosening zone.

[0039] like Figure 1As shown, the hollow anchor body 6 and the threaded rod body 11 are butt-jointed via a connecting sleeve 9, the connecting sleeve 9 is externally mounted on a positioner 10, a slurry outlet hole 8 is provided on the connecting sleeve 9, and the hollow anchor body 6 is connected to the slurry outlet hole 8. Specifically, the connecting sleeve 9 is a cylindrical structure, one end of the connecting sleeve 9 is connected to the hollow anchor body 6, and the other end is connected to the threaded rod body 11, and a plurality of slurry outlet holes 8 are provided on the side wall of the connecting sleeve 9. After the connecting sleeve 9 is connected to the hollow anchor body 6, the internal channel of the connecting sleeve 9 is connected to the grouting channel inside the hollow anchor body 6, so that the slurry from the hollow anchor body 6 can enter the connecting sleeve 9, and be discharged from the connecting sleeve 9 through the slurry outlet hole 8 and enter the borehole. There are three groups of slurry outlet holes 8 provided on the connecting sleeve 9, which are arranged in sequence along the axial direction of the connecting sleeve 9, and each group is provided with four slurry outlet holes 8, and adjacent groups of slurry outlet holes 8 are arranged in staggered positions.

[0040] The other end of the hollow anchor body 6 is connected to the anchor, and the entire length of the hollow anchor body 6 is threaded. The connecting sleeve 9 has sufficient rigidity, and the connecting sleeve 9 and the hollow anchor body 6 are threadedly matched to enable slurry to enter the borehole from the hollow anchor body 6 through the slurry outlet hole 8 on the connecting sleeve 9.

[0041] A group of arc-shaped positioners 10 are also installed on the outer periphery of the connecting sleeve 9. The positioners 10 are arranged every 120 degrees to support the hollow anchor body 6 so that the hollow anchor body 6 is in a central position in the drilled hole.

[0042] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the anchor includes a pad 3 and a nut 1. The pad 3 is sleeved outside the hollow anchor body 6. One side of the pad 3 abuts against the slurry stopper 5, and the other side abuts against the nut 1. An exhaust hole 4 is opened on the pad 3, and the nut 1 cooperates with the threaded section of the hollow anchor body 6.

[0043] In this embodiment, Figure 3 As shown, the pad 3 is a double-sided steel ring hole-entry pad 3. The pad 3 is provided with an inner ring steel ring 18 adapted to the drill hole on the side facing the drill hole. The inner ring steel ring 18 can fit the hole wall and be stuck in the drill hole for preliminary fixation, which facilitates the installation of the entire anchor. The outer side of the pad 3 is provided with an outer ring steel ring 16 of the same diameter as the nut slot 15, which is used for rotational fixation with the nut 1. The aperture of the central opening of the pad 3 matches the diameter of the hollow anchor body 6. The top surface of the pad 3 has a certain curvature, forming a curved protrusion 17. The diameter range of the curved protrusion 17 is slightly smaller than the diameter of the nut slot 15. The back of the curved protrusion 17 allows the edge of the pad 3 to better fit the rock surface of different angles.

[0044] The nut 1 is abutted against the backing plate 3 through the anti-loosening washer 2. The outer diameter of the anti-loosening washer 2 matches the inner diameter of the annular steel ring 16 on the outer side of the backing plate, so that the anti-loosening washer 2 can be placed inside the annular steel ring 16 on the outer side of the backing plate. The thread of the inner ring of the nut 1 matches the thread of the hollow anchor rod body 6, which is used to rotate the anchor rod body. An annular nut clamping groove 15 is provided on the end face of the nut 1 facing the backing plate 3. The radial width of the nut clamping groove 15 matches the radial thickness of the annular steel ring 16 on the outer side of the backing plate. The axial depth of the nut clamping groove 15 is greater than the axial length of the annular steel ring 16 on the outer side of the backing plate, so that the annular steel ring 16 on the outer side of the backing plate can be inserted into the nut clamping groove 15 along the axial direction. At the same time, one axial end of the anti-loosening washer 2 abuts against the backing plate 3, and the other end is tightened by the end face of the nut 1 and pressed into the annular steel ring 16 on the outer side of the backing plate.

[0045] The backing plate 3, the anti-loosening washer 2 and the nut 1 are sequentially inserted into the hollow anchor body 6. The three can be closely fitted to each other by rotating the nut 1, so that the rock mass, the anchor body and the anchor form a stable whole to prevent loosening.

[0046] like Figure 4 As shown, a vent hole is provided on the backing plate 3. When the annular steel bar inside the backing plate 3 is inserted into the anchor hole, it is inserted together with the stop grout plug 5. The stop grout plug 5 is also provided with a corresponding exhaust hole 4, which is used for grouting exhaust or inserting the exhaust pipe 7 to exhaust. The stop grout plug 5 is sleeved on the hollow anchor rod body 6 and is firmly clamped with the backing plate 3. The stop grout plug 5 and the backing plate 3 at the hole mouth jointly realize the function of sealing the hole and stopping grouting.

[0047] The diameter of the exhaust pipe 7 matches the exhaust hole 4 provided on the backing plate 3 and the grout stopper 5, and can extend to the anchor crown 12 at the bottom of the borehole when in use, so as to realize the exhaust of the elevation grouting.

[0048] In this embodiment, the injected slurry uses expansive cement mortar. The expansive cement has high early strength, a large increase in later strength, and a stable increase in long-term strength. After being strengthened, the expansive cement has expansion self-stress inside itself, and produces a stronger grip after combining with the threaded rod body 11. The expansive cement mortar quickly fills the seams and holes and expands and hardens to enhance the anchoring ability of the anchor rod. It has a good anchoring effect on weak surrounding rocks and has good waterproofness and durability.

[0049] When the anchor is installed at an elevation angle, the grouting liquid is injected from the hollow anchor body 6, and then gradually fills the borehole through the grouting hole 8 of the connecting sleeve 9, and the grout flows upward from the hole mouth to the anchor at the bottom of the hole, and the air in the borehole is gradually discharged from the bottom of the hole through the pre-inserted exhaust pipe 7. When the anchor is installed at a depression angle, the grout gradually flows from the anchor at the bottom of the hole to the hole mouth, and the air in the borehole is directly discharged from the exhaust hole 4. The functions of elevation angle grouting and depression angle grouting are used according to needs to improve the reliability of anchor grouting.

[0050] Example 2 In another typical embodiment of the present invention, Figure 1-Figure 6 As shown, a construction method of a screw-in self-locking combined hollow anchor system is provided, using the screw-in self-locking combined hollow anchor system as in Example 1.

[0051] A construction method for a screw-in self-locking combined hollow anchor system, comprising: Assemble the hollow anchor rod body 6 and the threaded rod body 11, and pre-assemble the anchor crown 12 and the threaded rod body 11; The anchor crown 12 is placed into the borehole using the hollow anchor rod body 6 and the threaded rod body 11, and the extrusion section is kept away from the variable diameter hole, and the anchor crown 12 corresponding to the variable diameter hole is in an unexpanded state until the anchor crown 12 reaches the bottom of the borehole; Rotating the hollow anchor rod body 6 drives the threaded rod body 11 to rotate in coordination with the guide hole, so that the positioning section and the extrusion section of the threaded rod body 11 are pushed into the anchor crown 12; The positioning pins 13 successively pass over the slots 21 and then probe into the slots 21 they match, preventing the threaded rod 11 from coming out of the anchor crown 12; the extrusion section gradually probes into the variable diameter hole, causing the area of ​​the anchor crown 12 corresponding to the variable diameter hole to expand and fill densely for anchoring; Anchors are installed on the hollow anchor rod body 6 and prestress is applied, and grouting is performed on the drilled hole.

[0052] As the threaded rod 11 moves along the inside of the anchor crown 12 , the positioning pin 13 first penetrates into the slot 21 when passing through the slot 21 , and then as the threaded rod 11 moves further, the guide surface is forced to push the positioning pin 13 back into the threaded rod 11 to pass through the slot 21 to reach the next slot 21 .

[0053] Specific, combined Figure 1-Figure 6 The construction method of the screw-in self-locking combined hollow anchor system includes the following detailed steps: (1) Preparation work: prepare to screw in the various components of the self-locking combined hollow anchor system and the supporting installation equipment, assemble the initial anchoring device according to the requirements of the drawings, and prepare the fast-hardening expansion cement slurry; (2) Measurement and marking: after the initial spraying of the tunnel is completed to form the concrete surface layer, measurement and setting out are carried out to determine the anchor drilling positions and mark them; (3) Drilling: Use an intelligent anchor trolley to drill holes, and use a high-precision drill bit that is suitable for screwing into self-locking anchors.

[0054] (4) Hole cleaning: Use the compressed air or high-pressure water provided by the intelligent anchor trolley to flush out the gravel in the borehole.

[0055] (5) Insert the anchor rod. Pre-connect the hollow anchor rod body 6 and the threaded rod body 11 with the connecting sleeve 9, and then insert the positioning pin 13 of the first layer of the positioning section of the front end of the threaded rod body 11 into the first layer of the slot 21 of the anchor crown 12. Put the early strength anchor into the front end of the positioning section. The early strength anchor is an early strength cement roll. Use an intelligent anchor trolley to push the self-locking combined hollow anchor system into the drilled anchor hole. When pushing, be careful not to open the semi-curved steel sheet 20. Keep the semi-curved steel sheet 20 at the front end of the anchor crown 12 in the minimum diameter state to avoid excessive diameter after expansion, and ensure that the anchor crown 12 reaches the bottom of the borehole smoothly.

[0056] (6) Rotational self-locking. After the anchor crown 12 successfully reaches the bottom of the borehole, the bolting machine of the intelligent anchor trolley pushes and rotates the rod body to make the three-layer positioning pin 13 of the threaded rod body 11 snap into the three-layer slot 21 of the anchor crown 12. The semi-curved steel sheet 20 of the anchor crown 12 is fully opened at the bottom of the borehole. At the same time, the threaded rod body 11 breaks and squeezes the early-strength anchoring agent and fills it densely in the anchor crown 12. At this time, the anchor crown 12 is tightly attached to the borehole to form an early-strength anchor body.

[0057] (7) Install the anchor. The stop plug 5, double-sided steel ring hole-entry pad 3, anti-loosening washer 2 and nut 1 are installed on the hollow anchor body 6 in sequence. After the early-strength anchor body at the anchor crown 12 reaches the required strength, rotate the nut 1 to anchor the double-sided steel ring hole-entry pad 3, anti-loosening washer 2 and nut 1, and then use the anchor bolt machine to rotate the nut 1 to apply preliminary prestress to ensure that the anchor and the anchor crown 12 are anchored and the anchor is fixed in the anchor hole.

[0058] (8) Apply prestress. The hollow anchor body 6 can be tensioned by an anchor machine, anchor tensioner or torque wrench of an intelligent anchor trolley and the nut 1 and the pad 3 can be further tightened to apply prestress to the anchor to a specified value. For rapid on-site construction, a pneumatic wrench with rated torque after process testing can also be used.

[0059] (9) Grouting. The grouting material is fast-hardening expansion cement slurry. Before grouting, all the slurry in the feeder is pumped back into the feeder so that the slurry is fully mixed by the pump before grouting the anchor. The slurry has good workability and good grouting effect.

[0060] (10) Quality inspection: Use anchor rod nondestructive testing instruments to inspect construction quality.

[0061] The screw-in self-locking combined hollow anchor system uses pressure expansion self-locking to make the anchor crown 12 fully contact with the surrounding rock mass in the annular direction of the borehole and at the bottom of the borehole, and fill the gaps with anchoring agent, so that the early anchor body and rock mass at the anchor crown 12 have sufficient connectivity to form a stable whole, thereby improving the reliability of the entire anchor support.

[0062] The structure of nut 1, anti-loosening washer 2 and double-sided steel ring hole-entry pad 3 with slot 21 makes the three parts of the anchor have sufficient anchoring force and plays a good anti-loosening effect. Due to the rod centering measure, the full self-waterproof expansion slurry can ensure that the threaded rod 11 will not fail for many years. The exhaust pipe 7 can be disassembled and can be used for elevation and depression angle anchor construction according to actual conditions. The performance of the rotating self-locking combined hollow anchor system meets the actual construction needs and is easy to construct. It can be widely promoted and used in surrounding rock tunnels of various grades.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A screw-in self-locking combined hollow anchor system, characterized in that: include: The hollow anchor rod body is equipped with an anchor; The end of the threaded rod body is butted with the end of the hollow anchor rod body. The threaded rod body is provided with a positioning section and an extrusion section. The positioning section is provided with a positioning needle that can be extended and retracted in the radial direction. Along the axial direction of the threaded rod body, an inclined guide surface is provided on the side of the positioning needle away from the hollow anchor rod body to receive the thrust to retract the positioning needle into the threaded rod body. The anchor crown is a cylindrical structure with a guide hole, a through hole and a reducing hole distributed in sequence along the axial direction. The guide hole is an internal threaded hole with an inner wall provided with a thread matching the outer thread of the threaded rod. The inner wall of the through hole is provided with a slot for a one-way locking positioning pin. The reducing hole gradually reduces in diameter in the direction away from the hollow anchor rod body to accommodate the extrusion section.

2. The screw-in self-locking combined hollow anchor system according to claim 1, characterized in that: The positioning needles are provided in a plurality of groups, and the plurality of groups of positioning needles are spaced apart and distributed along the axis of the threaded rod body. Each group of positioning needles is provided with two positioning needles, and the two positioning needles in the same group abut against the resilient member together.

3. The screw-in self-locking combined hollow anchor system according to claim 2, characterized in that: There are multiple slots along the axial direction of the anchor crown, and the multiple slots are distributed corresponding to the multiple groups of positioning pins. The positioning pins follow the movement of the threaded rod relative to the anchor crown to pass through other slots and reach the slot corresponding to the positioning pin, thereby unidirectionally stopping the relative movement of the threaded rod and the anchor crown.

4. The screw-in self-locking combined hollow anchor system according to claim 2, characterized in that: Along the axial direction of the threaded rod body away from the hollow anchor rod body, the lengths of the multiple groups of positioning pins protruding out of the circumference of the threaded rod body gradually increase, and the corresponding groove depth gradually increases.

5. The screw-in self-locking combined hollow anchor system according to claim 1, characterized in that: The extrusion section is closer to the end of the threaded rod body than the positioning section. The end of the threaded rod body is an end away from the hollow anchor rod body. The extrusion section passes through the guide hole and the through hole in sequence and then probes into the variable diameter hole.

6. The screw-in self-locking combined hollow anchor system according to claim 5, characterized in that: The outer peripheral wall of the anchor crown is provided with concave and convex patterns distributed alternately, and the anchor crown is coaxially matched with the threaded rod body.

7. The screw-in self-locking combined hollow anchor system according to claim 1, characterized in that: The anchor comprises a pad and a nut. The pad is sleeved outside the hollow anchor body, one side of the pad abuts against the slurry stopper, and the other side abuts against the nut. An exhaust hole is opened on the pad, and the nut cooperates with the threaded section of the hollow anchor body.

8. The screw-in self-locking combined hollow anchor system according to claim 1, characterized in that: The hollow anchor rod body and the threaded rod body are butted against each other via a connecting sleeve, the connecting sleeve is externally mounted on a positioner, a slurry outlet hole is provided on the connecting sleeve, and the hollow anchor rod body is connected to the slurry outlet hole.

9. A construction method of a screw-in self-locking combined hollow anchor system, using the screw-in self-locking combined hollow anchor system as claimed in any one of claims 1 to 8, characterized in that: include: Assemble the hollow anchor rod body and the threaded rod body, and pre-assemble the anchor crown and the threaded rod body; The anchor crown is placed into the borehole using the hollow anchor rod body and the threaded rod body, the extrusion section is kept separated from the variable diameter hole, and the anchor crown corresponding to the variable diameter hole is in an unexpanded state until the anchor crown reaches the bottom of the borehole; Rotating the hollow anchor rod body drives the threaded rod body to rotate in coordination with the guide hole, so that the positioning section and the extrusion section of the threaded rod body are pushed into the interior of the anchor crown; The positioning pin passes through other slots and then enters the slot it matches, preventing the threaded rod from coming out of the anchor crown; the extrusion section gradually enters the variable diameter hole, causing the anchor crown area corresponding to the variable diameter hole to expand and fill densely for anchoring; Anchors are installed on the hollow anchor rod body and prestress is applied, and grouting is performed on the drilled hole.

10. The construction method of the screw-in self-locking combined hollow anchor system according to claim 9, characterized in that: As the threaded rod moves along the inside of the anchor crown, the positioning pin first penetrates into the slot when passing through the slot, and then as the threaded rod moves further, the guide surface is forced to push the positioning pin back into the threaded rod to pass through the slot to reach the next slot.

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