Energy-absorbing grouting anchor rod and using method thereof

Abstract

The invention discloses an energy-absorbing grouting anchor rod and a using method thereof, the anchor rod comprises a grouting anchoring section, a self-expansion sliding energy-absorbing anchoring section and an end instant anchoring section, and the grouting anchoring section, the self-expansion sliding energy-absorbing anchoring section and the end instant anchoring section are sequentially distributed in the axial direction. Grouting reinforcement of broken surrounding rock and cracked rock mass can be achieved through the hollow threaded steel and the slurry return connecting sleeve, the strength of the surrounding rock in a cracked area is improved, the cracked structural face of the rock mass is sealed through slurry, a protection layer can be formed on the surface of the anchor rod, and the durability of the anchor rod can be improved; full-length anchoring can be conducted on the anchor rod after prestress is applied through cooperation of the self-expansion anchoring cartridge and grouting, the relaxation effect of the prestress is reduced, the self-stabilization capacity of surrounding rock in an anchoring area and the initial deformation rigidity of the anchor rod are improved, and the anchor rod has the more effective control effect on surrounding rock deformation. By means of the constant-resistance slippage deformation characteristic of the self-expansion slippage energy absorption anchoring section, when surrounding rock is subjected to large deformation or rockburst impact load, the large deformation and energy absorption functions of the anchor rod can be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of mine roadway and geotechnical engineering support, and particularly relates to an energy-absorbing grouting bolt and a using method thereof. Background Technique

[0002] With the development of social economy, underground geotechnical engineering such as transportation, hydropower, and mining has also developed rapidly. Due to its high efficiency and safety, bolt support has been widely used in these underground geotechnical engineering. Therefore, in-depth research on bolt support is of great significance for ensuring the safe and efficient implementation of projects.

[0003] In shallow-buried projects, the main function of bolts is to maintain the surrounding rock that tends to loosen due to gravity and keep it in a stable state. In recent years, with the increase in the burial depth of projects, the surrounding rock shows the characteristics of "three highs and one disturbance" of high ground pressure, high ground temperature, high osmotic pressure, and strong mining disturbance. Compared with shallow-buried projects, its most prominent feature is that high stress concentration is likely to occur after the project excavation, which in turn leads to frequent occurrence of engineering disasters such as large deformation of the surrounding rock and rock burst, causing great losses to the lives, property, and safety of construction workers and seriously affecting the construction efficiency and safety.

[0004] Traditional anchoring systems are mostly rigid supports. During the occurrence of large deformation of the surrounding rock and rock burst disasters, it is very easy to cause premature breakage and failure of the bolts. In addition, the bolt support area in deep engineering is usually accompanied by harsh conditions such as corrosive water, high temperature, and high humidity, which have a serious impact on the durability of the support system. If effective anti-corrosion measures are not taken, it will accelerate the corrosion process of the bolts and increase the risk of bolt failure due to corrosion.

[0005] Under deep buried high ground stress conditions, after the excavation of roadways, chambers or tunnels, the range of the broken zone formed around the excavation space is much larger than that under shallow buried conditions, and rock mass cracking often occurs in the broken zone. Therefore, after the excavation of underground projects, applying pre-tightening force to the bolts in a timely manner can significantly increase the friction force between the surrounding rock fissures, effectively compensate the principal stress of the surrounding rock at the excavation site, inhibit the further expansion of the fissures, improve the shear strength of the rock mass fissures, prevent adverse phenomena such as roof separation and rock blocks being ejected due to extrusion, and can also effectively inhibit the gestation process of rock burst. However, after the traditional bonded bolts are applied with prestress, due to the creep of the anchoring agent and the surrounding rock, the prestress of the bolts often has a relaxation effect, seriously affecting the prestress application effect.

[0006] Research shows that grouting of cracked rock masses can increase the strength of broken surrounding rock, inhibit further cracking of the broken part, enhance the self-stabilizing ability of the surrounding rock, thereby suppressing the development of the broken zone of the surrounding rock towards the depth, and further reducing the probability of rockburst occurrence. When appropriate grouting technology is adopted for the bolt, while effectively strengthening and sealing the cracked rock mass, it can also provide a mortar protection layer for the bolt, thus significantly enhancing the durability of the anchoring system.

[0007] To effectively control the large deformation and rockburst disasters of deep-buried high in-situ stress surrounding rock, on the basis of ensuring sufficient support strength, the bolt also needs to have large deformation ability, that is, the bolt should possess energy absorption characteristics.

[0008] In response to the support requirements of deep geotechnical engineering, many new types of energy-absorbing bolts have been developed successively. According to different energy absorption principles, the existing energy-absorbing bolts can be divided into two categories. The first type of energy-absorbing bolt mainly realizes the energy absorption function through the plastic deformation of the rod body debonding from the anchoring agent, and the second type of energy-absorbing bolt realizes the energy absorption function by using the slip or deformation device made of metal material.

[0009] However, neither of the existing two types of energy-absorbing bolts has the functions of grouting and strengthening cracked surrounding rock and preventing prestress relaxation. Among them, although the first type of energy-absorbing bolt has a relatively large anchoring force, due to the relatively low elongation rate of ordinary steel itself, its overall deformation ability is limited; although the second type of energy-absorbing bolt has a relatively large deformation amount, due to the limited slip resistance of the slip deformation device, the support strength is often insufficient, and because the metal energy absorption structure is extremely easy to be exposed to the corrosive environment, its durability is insufficient. Summary of the Invention

[0010] Aiming at the problems existing in the prior art, the present invention provides an energy-absorbing grouting bolt and its using method. Through the hollow threaded steel and the return slurry connecting sleeve, grouting and strengthening of the broken surrounding rock and cracked rock mass can be realized, increasing the strength of the surrounding rock in the cracked area. By using the slurry to seal the rock mass cracking structural plane, a protection layer can be formed on the surface of the hollow threaded steel and the durability of the bolt can be increased; through the cooperation of the self-expanding anchoring cartridge and grouting, full-length anchoring of the bolt after prestress is applied can be realized, effectively reducing the relaxation effect of the prestress, increasing the self-stabilizing ability of the surrounding rock in the anchoring area and the initial deformation stiffness of the bolt, so that the bolt can achieve a more effective control effect on the surrounding rock deformation; through the constant resistance slip deformation characteristic of the self-expanding slip energy-absorbing anchoring section, when large deformation or rockburst impact load occurs in the surrounding rock, the large deformation and energy absorption functions of the bolt can be realized.

[0011] To achieve the above object, the present invention adopts the following technical solution: An energy-absorbing grouting bolt includes a grouting and anchoring section, a self-expanding slip energy-absorbing anchoring section, and an end instant anchoring section, and the grouting and anchoring section, the self-expanding slip energy-absorbing anchoring section, and the end instant anchoring section are distributed axially in sequence.

[0012] The grouting anchorage section includes hollow threaded steel bars, slurry return connecting sleeves and slurry stopping plugs; the slurry return connecting sleeves are installed at the front ends of the hollow threaded steel bars, the slurry stopping plugs are installed at the tail ends of the hollow threaded steel bars, and a backing plate and a fastening nut are sequentially arranged outside the slurry stopping plugs.

[0013] A slurry return hole is arranged in the middle of the slurry return connecting sleeve; the inner surface of the middle part of the slurry return connecting sleeve is a threadless section, and the slurry return hole is communicated with the inner cavity of the threadless section of the slurry return connecting sleeve; the inner surfaces of the slurry return connecting sleeve on both sides of the threadless section are respectively a first thread section and a second thread section; the front end of the hollow threaded steel bar is fixedly screwed together with the first thread section of the slurry return connecting sleeve.

[0014] The self-expanding slip energy-absorbing anchorage section includes solid threaded steel bars, self-expanding anchoring cartridges, slip cones, slip energy-absorbing tubes and compression nuts; the rear ends of the solid threaded steel bars are fixedly screwed together with the second thread sections of the slurry return connecting sleeves; the self-expanding anchoring cartridges, slip energy-absorbing tubes, slip cones and compression nuts are sequentially sleeved on the solid threaded steel bars; the rear ends of the self-expanding anchoring cartridges are axially abutted against the front ends of the slurry return connecting sleeves; the rear ends of the slip energy-absorbing tubes are axially abutted against the front ends of the self-expanding anchoring cartridges; the small-diameter section of the slip cone extends into the tube body of the slip energy-absorbing tube, and the conical surface of the slip cone is axially abutted against the front end of the slip energy-absorbing tube; the compression nut is axially abutted against the large-diameter end of the slip cone; the solid threaded steel bar has a reserved extended section relative to the compression nut.

[0015] The number of the self-expanding anchoring cartridges is several, and several self-expanding anchoring cartridges are sequentially distributed axially.

[0016] The self-expanding anchoring cartridge includes a hollow cartridge cylinder, a cartridge cylinder annular cover and an anchoring agent; the hollow cartridge cylinder adopts a double-layer structure with a single-side opening, and the cartridge cylinder annular cover is arranged at the annular opening of the hollow cartridge cylinder; the anchoring agent is filled in the annular space between the inner cylinder wall and the outer cylinder wall of the hollow cartridge cylinder; several water-permeable holes are uniformly arranged on the outer cylinder wall of the hollow cartridge cylinder, and absorbent paper is pasted on the outer surface of the hollow cartridge cylinder.

[0017] The end instant anchorage section adopts an expanding shell anchor head, and the expanding shell anchor head is fixedly screwed together with the front end of the reserved extended section of the solid threaded steel bar.

[0018] A using method of an energy-absorbing grouting bolt includes the following steps:

[0019] Step 1: Connect the hollow threaded steel bar and the solid threaded steel bar together by using the slurry return connecting sleeve;

[0020] Step 2: Successively sleeved the self - expanding anchoring cartridge, sliding energy - absorbing tube, sliding cone and compression nut on the solid threaded steel, and then tightened the compression nut to compress and fix the self - expanding anchoring cartridge, sliding energy - absorbing tube and sliding cone between the slurry - returning connecting sleeve and the compression nut;

[0021] Step 3: Directly spray clear water on the surface of the self - expanding anchoring cartridge, or immerse the self - expanding anchoring cartridge in clear water for soaking to make the self - expanding anchoring cartridge fully absorb water;

[0022] Step 4: Use a rock bolt drill or a rock drill to complete the processing of the surrounding rock borehole;

[0023] Step 5: Install the swelled shell anchor head at the front end of the reserved extended section of the solid threaded steel, orient the swelled shell anchor head towards the surrounding rock borehole and insert it into the hole until the swelled shell anchor head abuts against the bottom of the surrounding rock borehole. Then use a rock bolt installation machine to tighten the hollow threaded steel, so as to drive the wedge body of the swelled shell anchor head to move axially. Through the axially moving wedge body, the shell pieces of the swelled shell anchor head are expanded outwards, and an instant anchoring force is formed between the expanded shell pieces and the hole wall of the surrounding rock borehole;

[0024] Step 6: Install the grout - stopping plug, bearing plate and fastening nut on the hollow threaded steel in sequence. The grout - stopping plug seals the orifice of the surrounding rock borehole, and then use an electric torque wrench to screw the fastening nut until the application of the pre - tightening force of the rock bolt is completed;

[0025] Step 7: Connect the grouting system to the hollow threaded steel by using a grouting joint. The grout enters the surrounding rock borehole through the hollow threaded steel and the slurry - returning holes of the slurry - returning connecting sleeve in sequence until the grouting operation is completed.

[0026] The beneficial effects of the present invention:

[0027] The energy - absorbing grouting rock bolt and its using method of the present invention can realize the grouting reinforcement of broken surrounding rock and cracked rock mass through the hollow threaded steel and the slurry - returning connecting sleeve, increase the strength of the surrounding rock in the cracking area, and seal the rock mass cracking structural plane by the grout, which can not only form a protective layer on the surface of the hollow threaded steel, but also increase the durability of the rock bolt; through the cooperation of the self - expanding anchoring cartridge and grouting, the fully - length anchoring of the rock bolt after the application of prestress can be realized, effectively reducing the relaxation effect of prestress, increasing the self - stability ability of the surrounding rock in the anchoring area and the initial deformation stiffness of the rock bolt, so that the rock bolt can play a more effective control effect on the surrounding rock deformation; through the constant - resistance sliding deformation characteristic of the self - expanding sliding energy - absorbing anchoring section, when the surrounding rock undergoes large deformation or rock burst impact load, the large - deformation and energy - absorbing functions of the rock bolt can be realized. Brief Description of the Drawings

[0028] Figure 1 It is a structural schematic diagram of an energy - absorbing grouting rock bolt of the present invention;

[0029] Figure 2Stereogram of the self-expanding anchoring cartridge (absorbent paper not shown) of the present invention;

[0030] Figure 3 Cross-sectional view of the self-expanding anchoring cartridge of the present invention;

[0031] Figure 4 Cross-sectional view of the slurry return connecting sleeve;

[0032] In the figure, I - grouting anchoring section, II - self-expanding sliding energy-absorbing anchoring section, III - end instant anchoring section, 1 - hollow threaded steel, 2 - slurry return connecting sleeve, 21 - slurry return hole, 22 - non-threaded section, 23 - first threaded section, 24 - second threaded section, 3 - grout stop plug, 4 - backing plate, 5 - fastening nut, 6 - solid threaded steel, 7 - self-expanding anchoring cartridge, 71 - hollow cartridge cylinder, 72 - cartridge cylinder annular cover, 73 - anchoring agent, 74 - water permeable hole, 75 - absorbent paper, 8 - sliding cone, 9 - sliding energy-absorbing tube, 10 - compression nut, 11 - swelled shell anchor head. Specific embodiments

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] As Figures 1 to 4 shown, an energy-absorbing grouting bolt includes a grouting anchoring section I, a self-expanding sliding energy-absorbing anchoring section II and an end instant anchoring section III, and the grouting anchoring section I, the self-expanding sliding energy-absorbing anchoring section II and the end instant anchoring section III are distributed axially in sequence.

[0035] The grouting anchoring section I includes a hollow threaded steel 1, a slurry return connecting sleeve 2 and a grout stop plug 3; the slurry return connecting sleeve 2 is installed at the front end of the hollow threaded steel 1, the grout stop plug 3 is installed at the tail end of the hollow threaded steel 1, and a backing plate 4 and a fastening nut 5 are sequentially arranged outside the grout stop plug 3.

[0036] In this embodiment, the hollow threaded steel 1 is made of precision rolled threaded steel, the outer diameter of the hollow threaded steel 1 is 25 mm, the wall thickness of the hollow threaded steel 1 is 6 mm, and the ultimate tensile force of the hollow threaded steel 1 is 220 kN; the slurry return connecting sleeve 2 is made of Q410 steel, and the axial length of the slurry return connecting sleeve 2 is 150 mm; the grout stop plug 3 adopts a hollow conical structure, the material of the grout stop plug 3 is rubber, the inner diameter of the central hole of the grout stop plug 3 is 26 mm, the cone height of the grout stop plug 3 is 50 mm, and the diameter of the large end of the cone of the grout stop plug 3 is 51 mm.

[0037] A slurry return connection sleeve 2 is provided with a slurry return hole 21 in the middle; the inner surface of the middle part of the slurry return connection sleeve 2 is a non-threaded section 22, and the slurry return hole 21 communicates with the inner cavity of the slurry return connection sleeve 2 of the non-threaded section 22; the inner surfaces of the slurry return connection sleeve 2 on both sides of the non-threaded section 22 are a first threaded section 23 and a second threaded section 24 respectively; the front end of the hollow threaded steel 1 is fixedly screwed together with the first threaded section 23 of the slurry return connection sleeve 2.

[0038] In this embodiment, the diameter of the slurry return hole 21 is 8 mm, the axial length of the non-threaded section 22 is 10 mm, and the axial lengths of the first threaded section 23 and the second threaded section 24 are both 50 mm.

[0039] The self-expanding sliding energy-absorbing anchoring section II includes a solid threaded steel 6, a self-expanding anchoring cartridge 7, a sliding cone 8, a sliding energy-absorbing tube 9 and a compression nut 10; the rear end of the solid threaded steel 6 is fixedly screwed together with the second threaded section 24 of the slurry return connection sleeve 2; the self-expanding anchoring cartridge 7, the sliding energy-absorbing tube 9, the sliding cone 8 and the compression nut 10 are sequentially sleeved on the solid threaded steel 6; the rear end of the self-expanding anchoring cartridge 7 abuts against the front end of the slurry return connection sleeve 2 axially; the rear end of the sliding energy-absorbing tube 9 abuts against the front end of the self-expanding anchoring cartridge 7 axially; the small-diameter section of the sliding cone 8 extends into the tube body of the sliding energy-absorbing tube 9, and the conical surface of the sliding cone 8 abuts against the front end of the sliding energy-absorbing tube 9 axially; the compression nut 10 abuts against the large-diameter end of the sliding cone 8 axially; the solid threaded steel 6 has a reserved extended section relative to the compression nut 10.

[0040] In this embodiment, the solid threaded steel 6 is made of precision rolled threaded steel, the ultimate tensile force of the solid threaded steel 6 is greater than 310 kN, and the length of the reserved extended section of the solid threaded steel 6 relative to the compression nut 10 is 100 mm to 150 mm; the sliding cone 8 adopts a hollow conical structure, the material of the sliding cone 8 is 304 stainless steel, the diameter of the large-diameter end of the sliding cone 8 is 45 mm, the inner diameter of the central hole of the sliding cone 8 is 26 mm, and the conical height of the sliding cone 8 is 30 mm; the sliding energy-absorbing tube 9 is made of galvanized seamless steel pipe, the material of the sliding energy-absorbing tube 9 is Q235, the outer diameter of the sliding energy-absorbing tube 9 is 42 mm, the wall thickness of the sliding energy-absorbing tube 9 is 3 mm, and the axial length of the sliding energy-absorbing tube 9 is 300 mm.

[0041] The number of the self-expanding anchoring cartridges 7 is several, and several self-expanding anchoring cartridges 7 are distributed axially in sequence.

[0042] In this embodiment, the number of the self-expanding anchoring cartridges 7 is four, and the total length is 600 mm.

[0043] The self-expanding anchoring cartridge 7 includes a hollow cartridge cylinder 71, a cartridge cylinder annular cover 72 and an anchoring agent 73; the hollow cartridge cylinder 71 adopts a double-layer structure with a single-sided opening, and the cartridge cylinder annular cover 72 is arranged at the annular opening of the hollow cartridge cylinder 71; the anchoring agent 73 is filled in the annular space between the inner wall and the outer wall of the hollow cartridge cylinder 71; a plurality of water-permeable holes 74 are uniformly formed in the outer wall of the hollow cartridge cylinder 71, and a blotting paper 75 is pasted on the outer surface of the hollow cartridge cylinder 71.

[0044] In this embodiment, the material of the hollow cartridge cylinder 71 is plastic, the hollow cartridge cylinder 71 is manufactured by plastic molding process, the axial length of the hollow cartridge cylinder 71 is 150 mm, the outer diameter of the hollow cartridge cylinder 71 is 48 mm, the inner diameter of the hollow cartridge cylinder 71 is 27 mm, the wall thickness of both the inner wall and the outer wall of the hollow cartridge cylinder 71 is 0.5 mm, and the wall thickness of the closed end of the hollow cartridge cylinder 71 is 3 mm; the thickness of the cartridge cylinder annular cover 72 is 3 mm; the anchoring agent 73 is calcium oxide, and the filling density of the anchoring agent 73 in the annular space of the hollow cartridge cylinder 71 is 1.6 g / cm 3 ; the diameter of the water-permeable hole 74 is 4 mm.

[0045] The end immediate anchoring section III adopts a swelled shell anchor head 11, and the swelled shell anchor head 11 is fixedly screwed together with the front end of the reserved extended section of the solid threaded steel 6.

[0046] A using method of an energy-absorbing grouting bolt includes the following steps:

[0047] Step 1: Connect the hollow threaded steel 1 and the solid threaded steel 6 together by using a return slurry connecting sleeve 2;

[0048] Step 2: Sleeve a self-expanding anchoring cartridge 7, a sliding energy-absorbing tube 9, a sliding cone 8 and a compression nut 10 on the solid threaded steel 6 in sequence, and then tighten the compression nut 10 to press and fix the self-expanding anchoring cartridge 7, the sliding energy-absorbing tube 9 and the sliding cone 8 between the return slurry connecting sleeve 2 and the compression nut 10;

[0049] Step 3: Directly spray clear water on the surface of the self-expanding anchoring cartridge 7, or immerse the self-expanding anchoring cartridge 7 in clear water for soaking to make the self-expanding anchoring cartridge 7 fully absorb water;

[0050] In this embodiment, the self-expanding anchoring cartridge 7 realizes the water absorption of the anchoring agent 73 by the immersion method. The soaking time is 15 min. When there are no bubbles or only a small amount of bubbles emerging from the hollow anchoring cartridge 7, it can be taken out of the clear water.

[0051] Step 4: Use a bolt drilling rig or a rock drill to complete the processing of the surrounding rock borehole;

[0052] In this embodiment, the aperture of the surrounding rock borehole is 50 mm;

[0053] Step Five: Install the expanding shell anchor head 11 at the front end of the reserved extended section of the solid threaded steel 6, orient the expanding shell anchor head 11 towards the surrounding rock borehole and insert it into the hole until the expanding shell anchor head 11 abuts against the bottom of the surrounding rock borehole. Subsequently, use the bolt installation machine to tighten the hollow threaded steel 1 to drive the wedge of the expanding shell anchor head 11 to move axially. Through the axially moving wedge, the shell pieces of the expanding shell anchor head 11 are expanded outwards, and an instant anchoring force is formed between the expanded shell pieces and the hole wall of the surrounding rock borehole;

[0054] Step Six: Install the grout stopper 3, the bearing plate 4, and the fastening nut 5 on the hollow threaded steel 1 in sequence. The grout stopper 3 seals the orifice of the surrounding rock borehole. Then, use an electric torque wrench to tighten the fastening nut 5 until the application of the bolt pre-tightening force is completed;

[0055] Step Seven: Connect the grouting system to the hollow threaded steel 1 using the grouting joint. The grout passes through the hollow threaded steel 1 and the return grout holes 21 of the return grout connecting sleeve 2 into the surrounding rock borehole in sequence until the grouting operation is completed.

[0056] When the grouting operation is completed, the installation process of the bolt is also synchronously completed. During the subsequent working process of the bolt, when the surrounding rock deforms, the deformation of the bolt can be divided into four stages, namely the initial resistance increasing stage, the initial slip deformation energy absorption stage, the constant resistance slip deformation energy absorption stage, and the final deformation energy absorption stage.

[0057] In the initial resistance increasing stage, the bolt is anchored deep in the surrounding rock through the end instant anchoring section III and the self-expanding slip energy absorption anchoring section II. The surrounding rock deformation load is applied to the bolt rod body through the bond force of the grout in the grouting anchoring section I and the extrusion of the bearing plate 4. And the load of the bolt rod body will increase with the increase of the surrounding rock deformation. When the load of the bolt rod body is greater than the sum of the maximum static friction force at the interface between the self-expanding anchoring cartridge 7 and the solid threaded steel 6 and the anchoring force of the expanding shell anchor head 11, the solid threaded steel 6 debonds from the self-expanding anchoring cartridge 7 and starts to slide, and then the bolt enters the initial slip deformation energy absorption stage.

[0058] In the initial slip deformation energy absorption stage, there is no relative sliding between the self-expanding anchoring cartridge 7 and the hole wall of the surrounding rock borehole. The self-expanding anchoring cartridge 7 restricts the slip energy absorption tube 9 at the bottom of the surrounding rock borehole. As the slip cone 8 gradually slides into the slip energy absorption tube 9, the slip energy absorption tube 9 is gradually expanded and torn by the slip cone 8 and undergoes plastic deformation. At the same time, the slip energy absorption tube 9 axially compresses the self-expanding anchoring cartridge 7, making the working resistance of the bolt gradually increase until the slip cone 8 completely slides into the slip energy absorption tube 9, and then the bolt enters the constant resistance slip deformation energy absorption stage.

[0059] During the constant resistance slip deformation energy absorption stage, a relatively stable sliding resistance is generated between the slip cone 8 and the slip energy absorption tube 9, and the axial compression deformation of the self-expanding anchoring cartridge 7 stops until the slip cone 8 moves to the bottom of the slip energy absorption tube 9 and contacts the self-expanding anchoring cartridge 7. Subsequently, the bolt enters the final deformation energy absorption stage.

[0060] During the final deformation energy absorption stage, there is no relative sliding between the self-expanding anchoring cartridge 7 and the wall of the surrounding rock borehole. The slip cone 8 compresses the self-expanding anchoring cartridge 7, and the load of the bolt body gradually increases until the bolt body breaks.

[0061] The solutions in the embodiments are not intended to limit the protection scope of the present invention. Any equivalent implementation or modification without departing from the present invention is included in the protection scope of the present invention.

Claims

1. An energy absorbing grouting anchor, characterized in that: It comprises a grouting anchoring section, a self-expanding sliding energy absorbing anchoring section and an end instant anchoring section, wherein the grouting anchoring section, the self-expanding sliding energy absorbing anchoring section and the end instant anchoring section are sequentially distributed along the axial direction.

2. The energy absorbing grouting anchor according to claim 1, characterized in that: The grouting anchoring section includes a hollow threaded steel bar, a return grouting connection sleeve and a grouting stop plug; the return grouting connection sleeve is installed at the front end of the hollow threaded steel bar, the grouting stop plug is installed at the rear end of the hollow threaded steel bar, and a support plate and a fastening nut are arranged in sequence on the outside of the grouting stop plug.

3. The energy absorbing grouting anchor according to claim 2, characterized in that: A return slurry hole is arranged in the middle of the return slurry connecting sleeve; the inner surface of the middle part of the return slurry connecting sleeve is a non-threaded section, and the return slurry hole is communicated with the inner cavity of the return slurry connecting sleeve of the non-threaded section; the inner surfaces of the return slurry connecting sleeve on both sides of the non-threaded section are respectively the first threaded section and the second threaded section; the front end of the hollow threaded steel is fixedly screwed together with the first threaded section of the return slurry connecting sleeve.

4. The energy absorbing grouting anchor according to claim 3, characterized in that: The self-expanding sliding energy-absorbing anchor section includes solid threaded steel, a self-expanding anchor coil, a sliding cone, a sliding energy-absorbing tube and a clamping nut; the rear end of the solid threaded steel is fixedly screwed together with the second threaded section of the return-grouting connection sleeve; the self-expanding anchor coil, the sliding energy-absorbing tube, the sliding cone and the clamping nut are sequentially mounted on the solid threaded steel; the rear end of the self-expanding anchor coil is axially pressed against the front end of the return-grouting connection sleeve; the rear end of the sliding energy-absorbing tube is axially pressed against the front end of the self-expanding anchor coil; the small-diameter section of the sliding cone extends to the inside of the tube body of the sliding energy-absorbing tube, and the conical surface of the sliding cone is axially pressed against the front end of the sliding energy-absorbing tube; the clamping nut is axially pressed against the large-diameter end of the sliding cone; the solid threaded steel has a reserved overhanging section relative to the clamping nut.

5. The energy absorbing grouting anchor according to claim 4, characterized in that: The self-expanding anchoring medicine coils are in a plurality and are sequentially distributed along the axial direction.

6. The energy absorbing grouting anchor according to claim 4, characterized in that: The self-expanding anchoring medicine roll includes a hollow medicine roll cylinder, a medicine roll cylinder annular cover and an anchoring agent; the hollow medicine roll cylinder adopts a double-layer structure with a single-side opening, and the medicine roll cylinder annular cover is arranged at the annular opening of the hollow medicine roll cylinder; the anchoring agent is filled in the annular space between the inner layer cylinder wall and the outer layer cylinder wall of the hollow medicine roll cylinder; a plurality of water-permeable holes are evenly opened on the outer layer cylinder wall of the hollow medicine roll cylinder, and absorbent paper is pasted on the outer surface of the hollow medicine roll cylinder.

7. The energy absorbing grouting anchor according to claim 4, characterized in that: The instant anchoring section of the end adopts an expansion shell anchor head, and the expansion shell anchor head is fixedly screwed together with the front end of the reserved extension section of the solid threaded steel bar.

8. The method for using the energy absorbing grouting anchor rod according to claim 7, characterized in that: The steps include: Step 1: Use the return grouting sleeve to connect the hollow threaded steel bar and the solid threaded steel bar together; Step 2: Install the self-expanding anchoring coil, sliding energy absorbing tube, sliding cone and compression nut on the solid threaded steel in sequence, and then tighten the compression nut to compress and fix the self-expanding anchoring coil, sliding energy absorbing tube and sliding cone between the grouting connection sleeve and the compression nut; Step 3: directly spray clean water on the surface of the self-expanding anchor roll, or immerse the self-expanding anchor roll in clean water to allow the self-expanding anchor roll to fully absorb water; Step 4: Use an anchor drill or rock drill to complete the processing of surrounding rock drilling; Step 5: Install the expansion shell anchor head to the front end of the reserved extension section of the solid threaded steel bar, and insert the expansion shell anchor head toward the surrounding rock drill hole until the expansion shell anchor head contacts the bottom of the surrounding rock drill hole, and then tighten the hollow threaded steel bar using an anchor bolt installation machine to drive the wedge of the expansion shell anchor head to move axially, and the shell of the expansion shell anchor head is expanded outward by the axially moving wedge, so that an instant anchoring force is formed between the expanded shell and the wall of the surrounding rock drill hole; Step 6: Install the grout stopper, support plate and fastening nut on the hollow threaded steel in sequence, and seal the opening of the surrounding rock borehole with the grout stopper. Then, use an electric torque wrench to tighten the fastening nut until the anchor bolt preload is applied. Step 7: Use the grouting joint to connect the grouting system to the hollow threaded steel bar. The slurry enters the surrounding rock borehole through the hollow threaded steel bar and the grouting hole of the grouting connection sleeve in turn until the grouting operation is completed.

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