Composite grouting anchor rod for preventing impact damage, construction method and application in preventing rock burst

Abstract

The present application relates to a kind of composite grouting anchor rod of impact damage prevention and construction method and application in preventing rock burst, wherein grouting anchor rod includes the anchor rod with central passage and the spacer in the anchor rod central passage, the first end of anchor rod is sleeved with expansion sleeve, the outer periphery of expansion sleeve expands when anchor rod is against expansion sleeve, a plurality of through holes are arranged on the anchor rod between first end and spacer, limit recess is arranged in the position close to spacer in anchor rod, anchor joint is placed in the limit recess, prestressed pipe is connected to the right end of anchor joint, the right end of prestressed pipe is provided with thread and nut connected with thread, resisting disc is abutted between nut and the second end of anchor rod, the center hole of prestressed pipe is provided with material delivery pipe capable of passing through spacer.This grouting anchor rod can resist tensile failure, also can prevent shear failure, improve the adaptability of anchor rod construction to complex geological environment.

Description

TECHNICAL FIELD

[0001] The present application relates to a composite grouting anchor for preventing impact damage and a construction method and application in preventing rock burst. BACKGROUND

[0002] Roadway surrounding rock support technology is one of the key technologies to ensure the safety and efficiency of mining. Traditional support methods mainly include wood support, steel support, anchor support, and shotcrete support. These methods have been widely used in the past few decades and have achieved certain results. However, in the face of complex underground conditions, especially in high ground stress areas and mining affected areas, the limitations of traditional methods gradually appear. They are often difficult to adapt to the strong deformation of rock and the influence of dynamic load, and are prone to failure and damage of the support structure. In order to overcome these problems, researchers have begun to explore more scientific and efficient new support technologies in recent years. For example, the development of collapsible support, high-strength shotcrete, and prestressed anchor cable has greatly improved the overall stability and carrying capacity of the support system.

[0003] Anchor rods are a basic component of underground engineering and slope support systems, mainly functioning to reinforce the surrounding rock of roadways or other underground spaces together, utilizing the power of the surrounding rock for support. Anchor rods are not only widely used in mine roadways, but also used for the main reinforcement of engineering structures such as slopes, tunnels, and dam bodies. With the complexity of engineering geological conditions, traditional anchor rods have long been unable to meet the needs of actual construction. Liu Sihui et al. proposed a splitting grouting anchor and its construction method (Application No. CN202410085675.4), which includes a hollow anchor rod, a centering rod, an anchor cable, a grouting pipe, a connecting sleeve, and an anchoring head, solving problems existing in certain technologies. Peng Jun et al. proposed an internal expansion grouting anchor for roadway surrounding rock support and its support method (Application No. CN202410058358.3), mainly composed of a rod body, an anchor head, a fixing structure, a grouting structure, an exhaust pipe, and a sensor structure. Although these anchor rods have solved technical problems to some extent, the comprehensiveness of the anchor rods is relatively single, and the adaptability to complex conditions is poor. SUMMARY

[0004] In view of the above shortcomings of the prior art, the purpose of the present application is to provide a composite grouting anchor for preventing impact damage and a construction method. The composite grouting anchor for preventing impact damage can not only resist tensile failure but also prevent shear failure, improving the adaptability of anchor rod construction to complex geological environments.

[0005] The application discloses a composite grouting anchor rod capable of preventing impact damage, and belongs to the technical field of rock bolting.

[0006] Preferably, the limiting recess is conical, and the anchor joint is also conical and matched with the conical limiting recess.

[0007] Preferably, the spacer is fixedly arranged at one-third to one-half of the central channel of the anchor rod.

[0008] Preferably, the inner wall of the expansion sleeve is conical, the first end of the anchor rod is also conical, the large end of the conical shape is towards the second end of the anchor rod, and a plurality of slots are uniformly arranged on the circumferential direction of the side of the expansion sleeve towards the second end of the anchor rod.

[0009] Preferably, the anchor joint is coaxially arranged with the prestressed pipe and fixed by thread connection or welding.

[0010] Preferably, the limiting recess is formed by a conical bucket fixed in the central channel of the anchor rod, the large end of the conical bucket is welded to the inner wall of the central channel of the anchor rod, and the small end of the conical bucket is welded to a sleeve pipe, and the central channel of the sleeve pipe is used for penetrating the prestressed pipe.

[0011] Preferably, the anchor rod is divided into two pipe rods at the position of the spacer, the two pipe rods are fixed by thread connection at the end close to each other, the spacer is pressed on the groove bottom of the thread groove of the first pipe rod and the end surface of the second pipe rod, and the conical bucket is fixedly welded in the central channel close to the end surface of the second pipe rod.

[0012] Preferably, the material feeding pipe is a plastic pipe, the first end of the plastic pipe penetrates the spacer, and the second end of the plastic pipe penetrates the right end of the prestressed pipe.

[0013] Preferably, the outer periphery of the anchor rod is sleeved with a constant resistance sleeve made of NPR material or exotic metal material, the constant resistance sleeve is uniformly provided with slot seams on the circumferences of both ends, and the slot seams at both ends are arranged in a staggered manner in the circumferential direction.

[0014] The construction method of the composite grouting anchor rod against impact damage first drills a hole in the rock, inserts the expansion sleeve on the anchor rod into the hole, and expands the expansion sleeve to fasten with the hole by applying force to the anchor rod during the insertion process. Then, the nut is rotated to move the anchor joint towards the second end of the anchor rod, to further pre-tighten the anchor joint to the limiting groove and the anchor rod. Then, the concrete grout is poured into the central passage of the anchor rod through the feed pipe, and the grout overflows from the through hole into the hole. After the grout solidifies, the anchor rod is fixed.

[0015] The application of the composite grouting anchor rod against impact damage in preventing rock burst is characterized in that:

[0016] (1) Pre-stress is applied to the anchor rod. After the anchor rod 2 and the expansion sleeve 4 are inserted into the hole, the nut is rotated to apply pre-stress through the feed pipe 11 in the resisting disc 10 and the pre-stress pipe 8.

[0017] (2) High-pressure water injection. High-pressure water is injected through the right end port of the feed pipe 11, and the high-pressure water is injected into the high-stress rock mass through the through hole 5. The liquid pressure is used to open and expand the cracks in the rock, and the formation and expansion of the cracks are controlled to release the ground stress.

[0018] (3) High-risk rock mass stress release. After the high-pressure water is injected, a constant water injection pressure needs to be maintained.

[0019] (4) Water pumping and pressure relief. After the high-pressure water fully plays its role and causes the rock mass to break, the water pumping device is used to completely pump out the fissure water injected into the rock mass.

[0020] Grouting reinforcement. After the water pumping and pressure relief are completed, the concrete grout is injected into the feed pipe through the right end port of the feed pipe 11. With the injection and penetration of the grout, the grout gradually fills the cracks and voids in the rock mass, and forms an anchoring integrated structure with the anchor rod.

[0021] The main innovations of the present application are:

[0022] 1. Energy absorption support method: The support system of the present application can absorb and disperse the energy generated by impact ground pressure, rather than just bearing the energy.

[0023] 2. Impact prevention mechanism research: The anchor rod device of the present application can allow instantaneous tensile and shear deformation, greatly improving the single fixing defect of traditional anchor rods, and effectively preventing or reducing the impact of impact ground pressure.

[0024] 3. Composite performance application: The present application combines initial anchoring and later grouting, realizes the combination of in-situ modification technology and energy absorption support method, greatly improves the stability of the rock mass, and helps to improve the mechanical properties of the in-situ rock mass, creating a more stable and safe roadway environment for the rock mass to be supported.

[0025] 4. Coping with extreme conditions: In environments with frequent or particularly intense rock bursts, where traditional support methods are difficult to cope with, the material of the anchor bolts described in this invention (NPR material / exotic metal material) can adapt to extreme geological conditions, including but not limited to temperature, earthquakes, blasting disturbances, rock bursts, landslides, etc. Attached image description:

[0026] Figure 1 This is a schematic diagram of the front view structure of an embodiment of the present invention;

[0027] Figure 2 This is a three-dimensional structural schematic diagram of the expansion sleeve of the present invention;

[0028] Figure 3 This is a three-dimensional structural schematic diagram of the constant resistance sleeve of the present invention;

[0029] Figure 4 This is a schematic diagram of the front view structure of another embodiment of the present invention;

[0030] Figure 5 , 6 yes Figure 4 A partial view. Detailed implementation method:

[0031] The composite grouting anchor bolt of the present invention for impact protection includes an anchor bolt 2 having a central channel 1 and a spacer 3 disposed in the central channel of the anchor bolt. The spacer can be a spacer fixedly disposed at one-third to one-half of the central channel of the anchor bolt. The spacer can be fixed in the central channel by means of glue, or another method of fixing will be provided later.

[0032] An expansion sleeve 4 is fitted onto the first end of the anchor rod 2. When the anchor rod is tightened against the expansion sleeve, the outer circumference of the expansion sleeve expands. Specifically, the inner circumferential wall of the expansion sleeve 4 is conical, and the first end of the anchor rod is also conical (the end face of the first end of the anchor rod is closed). The larger end of the conical shape faces the second end of the anchor rod. Several grooves 12 are evenly distributed in the circumferential direction on the side of the expansion sleeve facing the second end of the anchor rod. When the anchor rod is tightened against the expansion sleeve, the grooves 12 make it easy for the outer circumference of the expansion sleeve to expand. When the expansion sleeve 4 and the anchor rod 2 are both inserted into the hole drilled in the rock, the second end of the anchor rod 2 can be struck to make the anchor rod 2, the expansion sleeve 4 and the drill hole more tightly locked.

[0033] Several through holes 5 are arranged on the anchor rod 2 at the position between the first end and the partition plate. These through holes 5 are used to allow concrete slurry, water, etc. to pass through the central channel.

[0034] The position of the anchor rod near the partition is provided with a limiting groove 6, which is tapered, and the anchor joint 7 is placed in the limiting groove, which is also tapered.

[0035] The anchor joint 7 is connected with the prestressed pipe 8, the right end of which passes through the second end of the anchor rod, and the anchor joint is coaxially arranged with the prestressed pipe and is fixed by thread connection or welding; the limiting groove 6 is formed by the tapered bucket 17 fixed in the central channel of the anchor rod, the large end of the tapered bucket is welded to the inner wall of the central channel of the anchor rod, and the small end of the tapered bucket is welded to the sleeve 16, and the center of the sleeve is used for passing through the prestressed pipe 8.

[0036] The right end of the prestressed pipe 8 is provided with a thread and a nut 9 connected with the thread, and the nut 9 abuts against the resisting disc 10 between the second end of the anchor rod 2, when the nut is screwed, the prestressed pipe 8 is pulled tight between the anchor joint 7 and the resisting disc 10, the central hole of the prestressed pipe is provided with the feeding pipe 11 capable of passing through the partition, the feeding pipe can be a plastic pipe, the first end of which passes through the partition, and the second end of which passes through the right end of the prestressed pipe, the concrete slurry or water is introduced into the right end of the feeding pipe 11, and the left end of the feeding pipe 11 passes through the partition 3, and the concrete slurry or water is overflowed from the through hole 5 after being introduced.

[0037] In one embodiment, the above-mentioned anchor rod 2 is divided into two pipe rods at the position where the partition is installed, the two pipe rods are fixed by thread connection at the end close to each other, the partition is pressed on the groove bottom of the thread groove 13 of the first pipe rod, and on the end face of the second pipe rod, that is, the partition is first attached to the end face of the second pipe rod, and then the two pipe rods are screwed, that is, the screwing and fixing of the two pipe rods and the fixing of the partition are realized, and the large end of the tapered bucket 17 is welded and fixed in the central channel close to the end face of the second pipe rod.

[0038] The above-mentioned anchor rod 2 is divided into two pipe rods at the position where the partition is installed, which not only facilitates the installation of the partition, but also facilitates the welding and fixing of the large end of the tapered bucket 17 in the central channel close to the end face of the second pipe rod.

[0039] The outer periphery of the above-mentioned anchor rod is provided with a constant resistance sleeve 14 made of NPR material or exotic metal material, the constant resistance sleeve is provided with slot joints 15 at both ends and in the circumferential direction, the slot joints at both ends are arranged in a staggered manner in the circumferential direction, and the inner circumferential wall of the constant resistance sleeve 14 and the outer circumferential wall of the anchor rod can also be tapered and matched in connection, like the tapered matching connection between the inner circumferential wall of the expansion sleeve 4 and the outer circumferential wall of the anchor rod 2.

[0040] In addition, the composite grouting anchor rod of the present application can also be applied to the construction of preventing rock burst:

[0041] Rockburst, as a geological disaster, poses a serious threat to mine safety due to its suddenness and destructive power. In deep mining activities, the sudden release of ground stress and the instantaneous ejection of rock not only endanger the safety of miners but also may cause equipment damage and production interruption, resulting in significant economic losses. Therefore, the importance of rockburst control cannot be ignored. Effective control measures can significantly reduce the frequency and intensity of rockburst, providing a safe working environment for miners and ensuring the smooth exploitation of mineral resources. In addition, as resource development deepens, rockburst problems are becoming increasingly prominent, and strengthening rockburst control has become a key to improving mine economic efficiency and achieving sustainable development.

[0042] As an advanced geotechnical engineering technique, hydraulic fracturing has shown unique effectiveness in preventing rockburst. This method pre-fractures rock with high-pressure water flow to reduce the rigidity of the rock mass and release internal stress, thereby effectively reducing the likelihood of rockburst. In high-risk areas such as deep mine exploitation, hydraulic fracturing can improve the stress state of rock, making it develop in a direction conducive to stability. Specifically, it controls the generation and propagation of cracks, disperses stress concentration areas, and reduces the risk of rockburst caused by excessive stress concentration.

[0043] The composite grouting anchor rod can achieve the effect of rockburst control through the "one-step water injection and two-step grouting" construction method. The specific construction steps are as follows:

[0044] (5) Apply pre-stress to the anchor rod. After completing the construction of placing the anchor rod 2 and the expansion sleeve 4 into the drill hole, pass the feed pipe 11 through the resistance disc 10 and the pre-stressed pipe 8, and rotate the nut to apply pre-stress. In general, the selection of anchor rod pre-tightening force should follow certain principles, such as no obvious separation, sliding of surrounding rock, and appearance of tensile stress. It is generally recommended that the anchor rod pre-tightening force be about 30% of the yield load of the anchor rod body;

[0045] (6) High-pressure water injection. Inject high-pressure water along the grouting port (the right end port of the feed pipe 11), and inject high-pressure water into the high-stress rock mass through the through hole 5. Use liquid pressure to open and expand the cracks in the rock, and control the formation and propagation of cracks to release ground stress;

[0046] (7) High-risk rock mass stress release. After injecting high-pressure water, a constant water injection pressure needs to be maintained. The maintenance time is determined according to the rock mass conditions. In general, the greater the rockburst tendency, the longer the stable water injection time. During the fracture process, the water pressure will exceed the tensile strength of the rock, causing the rock to break;

[0047] (8) Pumping and pressure relief, after the high-pressure water fully plays a role in causing rock mass to break, the pumping device (water pump) is used to completely pump out the fissure water injected into the rock mass; this pumping process not only helps to further reduce the internal stress of the rock mass, but also forms a fissure development area around the anchor rod to create favorable conditions for grouting of the anchor rod, and through pumping and pressure relief, the stress state of the rock mass can be effectively adjusted and improved to provide protection for the stability of the rock mass; at the same time, this method also helps to improve the permeability of the rock mass to provide convenience for possible drainage, thereby reducing the risk of rock burst caused by water pressure to a certain extent.

[0048] (9) Grouting reinforcement, in order to further improve the effect of anchor rod reinforcement, after pumping and pressure relief is completed, the slurry (concrete slurry) of a specific ratio is injected into the feed pipe through the grouting port; as the slurry is injected and permeated, the slurry gradually fills the fissures and voids in the rock mass to form an anchoring integrated structure with the anchor rod.

[0049] The above-mentioned "one-step water injection and two-step grouting" of the present application is a construction scheme based on the rock burst frequent area, when the anchor rod is installed, the anchor rod body collides with the surrounding rock mass to cause the plastic zone of the surrounding rock mass of the anchor rod and the distribution of micro-fissures; when the high stress concentration area is encountered, the fissure expansion range is wider, which provides a good basis for the penetration of high-pressure water; the rock burst prevention mechanism of the present application has two aspects: first, the anchor rod body collides with the surrounding rock mass to cause the plastic zone of the surrounding rock mass of the anchor rod, and the anchor rod borehole provides a stress release space for the rock burst high stress area; second, the water injection pressure of high-pressure water further expands the distribution space of the liquid to expand the rock burst prevention area and improve the rock burst prevention effect; third, pumping and pressure relief provides a buffer space for the rock mass to reduce the rigidity of the rock mass and release the internal stress, thereby effectively reducing the possibility of rock burst.

[0050] The above-mentioned constant resistance sleeve 14 adopts NPR material or exotic metal material, the NPR material is a new type of super material with special mechanical properties, which shows different physical properties, that is, when subjected to uniaxial tension or compression, instead of transverse shrinkage according to the conventional Poisson's ratio effect, transverse expansion occurs, the purpose of using the NPR material in the present application is to prevent radial shrinkage, bear a certain deformation, and provide constant resistance; the exotic metal material is a kind of material with unconventional physical properties, which shows different behavior from traditional metals in electron transport, magnetism and superconductivity, etc., realizing the combination of ultra-high flexibility of high molecular material and ultra-high strength of ultra-high strength steel, and maintaining unchanged in a wide temperature range of-80℃ to +80℃.

[0051] Manufacture of components of the present application:

[0052] (1) the preparation of the constant resistance sleeve, the constant resistance sleeve is prepared by using NPR material / singular metal material, and both sides of the constant resistance sleeve are pre-cut to form a slot joint 15, so that the diameters of both sides of the constant resistance sleeve are slightly larger than the original diameter;

[0053] (2) the preparation of the anchor rod structure, the anchor rod structure comprises a rod body, a resisting disc, a prestressed nut, a spacer, a feeding pipe, a prestressed pipe, an expansion sleeve and a constant resistance sleeve.

[0054] A. The rod body is divided into two parts by the spacer, the distance between the spacer and the end of the anchor rod is 1 / 3-1 / 2 of the length of the anchor rod, a small hole is pre-set in the middle of the spacer for the grouting pipe (feeding pipe) to pass through, and the grouting effect is realized.

[0055] B. The middle of the resisting disc is pre-set with a small hole at the center, the thickness of the resisting disc is 3-5 cm, and the resisting disc is placed between the rod body and the nut during construction, and is used for the application of the prestress of the anchor rod.

[0056] C. The nut is connected with the resisting disc, and is used for the application of the prestress of the anchor rod, and the prestress of the anchor rod is applied by tightening the nut.

[0057] (3) The expansion sleeve is placed at the end of the anchor rod before the anchor rod construction, one side of the expansion sleeve keeps the diameter unchanged, and the other side is pre-cut to form a pipe joint, so that the diameter of the cut side is slightly larger than that of the uncut side.

[0058] (4) The anchor rod body is placed in the reinforced rock mass, when the end of the anchor rod is extruded by the expansion sleeve, the end and the rock mass form extrusion stress, and the preliminary anchoring effect is achieved.

[0059] (5) After the anchoring of the anchor rod body, the constant resistance deformation sleeve is placed along the rod body at the fixed position of the constant resistance sleeve, so as to allow the constant resistance deformation in the later period.

[0060] (6) The resisting disc and the nut provide prestress application. The resisting disc is sleeved into the prestressed pipe in contact with the rod body, the nut is rotated to apply prestress, and the anchoring effect is enhanced again.

[0061] (7) Grouting is carried out along the grouting port to the feeding pipe to form an integrated anchoring structure.

[0062] The above only describes the preferred embodiments of the present application, and any changes and modifications made within the scope of the present application are also included in the scope of the present application.

Claims

1. A composite anti-impact damage grouting anchor rod, characterized in that: The anchor rod with a central channel and the spacer arranged in the central channel of the anchor rod, the first end of the anchor rod is sleeved with an expansion sleeve, the outer periphery of the expansion sleeve expands when the anchor rod is pressed against the expansion sleeve, a plurality of through holes are arranged on the anchor rod at a position between the first end and the spacer, a limiting groove is arranged on the anchor rod at a position close to the spacer, an anchor joint is arranged in the limiting groove, the anchor joint is connected with a prestressed pipe with a right end penetrating out of the second end of the anchor rod, a thread is arranged on the right end of the prestressed pipe, and a nut is connected with the thread, a resisting disc is arranged between the nut and the second end of the anchor rod, and a feeding pipe capable of penetrating through the spacer is arranged in the central hole of the prestressed pipe; the limiting groove is conical, the anchor joint is also conical, the inner peripheral wall of the expansion sleeve is conical, the first end of the anchor rod is also conical, the large ends of the conical shapes are all directed to the second end side of the anchor rod, and a plurality of slot joints are uniformly arranged on the circumferential direction of the expansion sleeve directed to the second end of the anchor rod.

2. The impact failure resistant composite grouted anchor rod of claim 1, wherein: The spacer is fixedly arranged at one third to one half of the central channel of the anchor rod.

3. The impact failure resistant composite grouted anchor rod of claim 2, wherein: The anchor joint is coaxially arranged with the prestressed pipe and is fixed by thread connection or welding.

4. The impact failure resistant composite grouted anchor rod of claim 1, wherein: The limiting groove is formed by a conical bucket fixed in the central channel of the anchor rod, the large end of the conical bucket is welded to the inner wall of the central channel of the anchor rod, and the small end of the conical bucket is welded to a sleeve pipe, and the central hole of the sleeve pipe is used for penetrating through the prestressed pipe.

5. The impact failure resistant composite grouted anchor rod of claim 4, wherein: The anchor rod is divided into two pipe rods at the position where the spacer is arranged, the two pipe rods are fixed by thread connection at the end close to each other, the spacer is pressed on the groove bottom of the thread groove of the first pipe rod and the end face of the second pipe rod, and the conical bucket is fixedly welded in the central channel close to the end face of the second pipe rod.

6. The impact failure resistant composite grouted anchor rod of claim 5, wherein: The feeding pipe is a plastic pipe, the first end of the plastic pipe penetrates through the spacer, and the second end of the plastic pipe penetrates out of the right end of the prestressed pipe.

7. A method of constructing a composite impact failure resistant grouted anchor according to any one of claims 1 to 6, characterised in that: First, drill a hole in the rock, put the expansion sleeve on the anchor rod and then put it into the hole, during the process of putting, the expansion sleeve expands to be tightly fixed with the hole due to the force applied to the anchor rod, then rotate the nut to make the anchor joint close to the second end of the anchor rod, so as to further pre-tighten the anchor joint to the limiting groove and the anchor rod, then pour the concrete slurry into the central channel of the anchor rod through the feeding pipe, the slurry overflows from the through hole into the hole, and the anchor rod is fixed after the slurry solidifies.

8. The application of the composite grouting anchor rod for preventing rock burst according to any one of claims 1-6, characterized in that: a prestress is applied to the anchor rod, after the anchor rod (2) and the expansion sleeve (4) are put into the hole, the nut is rotated to apply the prestress through the feeding pipe (11) penetrating through the spacer in the resisting disc (10) and the prestressed pipe (8); high-pressure water injection, high-pressure water is injected through the right end port of the feeding pipe (11), the high-pressure water is injected into the high-stress rock mass through the through hole (5), the liquid pressure is used to open and expand the cracks in the rock, and the purpose of releasing the ground stress is achieved by controlling the formation and expansion of the cracks; high-risk rock mass stress release, the constant water injection pressure needs to be maintained after the high-pressure water is injected; After the rock mass is broken by the high-pressure water, the pumping device is used to pump out the fissure water in the rock mass; After the pumping and pressure relief, the concrete grout is injected into the delivery pipe through the right end port of the delivery pipe (11); with the injection and penetration of the grout, the grout gradually fills the fissures and voids in the rock mass, and forms an anchoring integrated structure with the anchor rod.

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