CN111706374A

CN111706374A - Anchor head expansion resistance-increasing type drainable multistage yielding anchor rod

Info

Publication number: CN111706374A
Application number: CN202010611800.2A
Authority: CN
Inventors: 徐卫亚; 徐伟; 闫龙; 王环玲; 胡明涛
Original assignee: Hohai University HHU
Current assignee: Hohai University HHU
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2020-09-25

Abstract

The invention discloses an anchor head expansion resistance-increasing type drainable multistage yielding anchor rod which comprises a hollow threaded rod body, wherein a yielding device is arranged at the upper end of the hollow threaded rod body through a locking device, a yielding tray is arranged at the lower end of the yielding device, an expandable anchor head is arranged at the lower end part of the hollow threaded rod body, and a resistance-increasing device and a drain hole are arranged on the hollow threaded rod body at the lower part of the yielding tray. The anchor rod can release the variable performance of larger surrounding rock, bear larger deformation and meet the engineering requirement of large deformation of the soft rock tunnel; the joint cracks in the surrounding rock are filled by using the high-molecular grouting material, so that the overall performance and strength of the loose broken rock-soil body are improved after cementation, and the supporting effect is improved; the resistance-increasing device and the expandable anchor head are arranged, so that the friction resistance between the anchor rod and the surrounding rock is large, the stability of the supporting system is high, water in rock and soil bodies can be discharged in time, the stability of the surrounding rock is improved, an anticorrosive coating is carried out on the anchor rod component, and the corrosion of underground water is effectively prevented.

Description

Anchor head expansion resistance-increasing type drainable multistage yielding anchor rod

Technical Field

The invention relates to a multi-stage yielding anchor rod, in particular to an anchor head expansion resistance-increasing type drainable multi-stage yielding anchor rod.

Background

Soft rock, a special rock mass, has a relatively long duration of rheology and often exhibits significant large deformations and nonlinear rheological properties. Due to large buried depth, long tunnel distance and complex geological conditions, a series of special disaster geological problems can occur in the construction process of the soft rock tunnel, such as the large deformation problem of the high ground stress soft rock tunnel in the excavation process, the rock mass stress is released and redistributed in the tunnel excavation construction, the soft rock deformation rate is high, the convergence is slow, and unstable accidents such as collapse and the like are easy to occur if the support is not in time or is improper. If the secondary supporting time of the soft rock cavern is too early, the stress release of surrounding rocks is small, the requirement on supporting rock mass is high, and if the secondary supporting time is too late, the deformation of the cavern is too large, so that the normal use of the cavern is influenced. At present, the problem of large soft rock extrusion deformation is generally solved by using yielding anchor rods, the yielding anchor rods can adapt to large deformation, the mechanical structure slippage principle of the yielding anchor rods is utilized to adapt to the speed of soft rock deformation, and the effect of timely supporting is further achieved, but at present, key problems of the yielding anchor rods in soft rock engineering, such as the magnitude of yielding pressure, the control of yielding amount, the frictional resistance between the anchor rods and surrounding rock, drainage and the like, are not well perfected and solved, and the failure and the damage of a primary supporting structure are easily caused due to insufficient pressure and yielding amount; the yielding anchor rod cannot drain water, soft rock has obvious softening effect when meeting water, the strength of surrounding rock is reduced, and the supporting difficulty is increased; the anchor rod and surrounding rock frictional resistance are not enough, and the anchoring effect is influenced.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide an anchor head expansion resistance-increasing type drainable multi-stage yielding anchor rod capable of discharging water in surrounding rocks, maintaining the stability of the surrounding rocks and anchoring.

The technical scheme is as follows: the invention relates to an anchor head expansion resistance-increasing type drainable multistage yielding anchor rod which comprises a hollow threaded rod body, wherein a yielding device is arranged at the upper end of the hollow threaded rod body through a locking device, a yielding tray is arranged at the lower end of the yielding device, an expandable anchor head is arranged at the lower end part of the hollow threaded rod body, and a drain hole and a resistance increasing device are arranged on the hollow threaded rod body at the lower part of the yielding tray.

The resistance increasing device is arranged on the hollow threaded rod body at the lower part of the yielding tray, is crescent and is made of steel, so that the resistance of the anchoring section of the yielding anchor rod in the surrounding rock can be increased, and a drain hole is arranged in the middle of the resistance increasing device; an upper base plate is arranged between the locking device and the pressure yielding device through a rubber gasket, and a lower base plate is arranged between the pressure yielding tray and the pressure yielding device through a rubber gasket; the yielding device comprises a yielding sleeve, a spiral spring arranged in the yielding sleeve and a sawtooth-shaped yielding structure arranged on the hollow threaded rod body, the yielding sleeve is drum-shaped, the upper part of the spiral spring is a small-diameter end, the lower part of the spiral spring is a large-diameter end, the whole body is trapezoidal and is arranged according to an equilateral triangle, the spiral spring is prevented from being eccentrically stressed in the yielding process, the whole body of the hollow threaded rod body is provided with coarse threads, and the strength of the coarse threads and the resistance increasing device is greater than that of the rod body; the strength and the ductility of the rubber gasket meet the actual engineering requirements, the rubber gasket has certain elasticity, and certain variable performance of surrounding rocks can be absorbed in the supporting process. The expandable anchor head is prepared by copolymerizing sodium acrylate and acrylamide as monomers, has obvious water-swelling capacity and good tensile property, can increase the friction resistance between the expandable anchor head and surrounding rocks, and improves the stability of a supporting system; the water permeable concrete is poured into the hollow threaded rod body, and the water permeable filter cloth is wrapped outside the hollow threaded rod body, so that the water can be conveniently discharged, the loose rock-soil body is prevented from blocking the drain hole, and the drainage performance and the drainage efficiency are enhanced; the anchor head expansion resistance-increasing type drainable multi-stage yielding anchor rod is coated with an anti-corrosion treatment layer, the anti-corrosion treatment layer is an oil-resistant antistatic coating layer and an epoxy resin protective layer, the anti-corrosion performance is excellent, the service life is long, and the corrosion of underground water to an anchoring system can be effectively prevented; the anchor head expansion resistance-increasing type drainable multi-stage yielding anchor rod adopts a high-polymer grouting material to fill joint cracks of the surrounding rock at the anchoring section of the surrounding rock, loose and broken rock soil bodies are cemented into a whole, the high-polymer grouting material is prepared from resin and a catalyst, the grouting material has good fluidity, permeability, cohesiveness and expansibility, and has high strength and high gel speed, can quickly permeate into tiny pores of the soft rock surrounding rock, expands 1 to 2 times and expands about 25 times when meeting water, and has good flexibility, sustainability and long service life after being consolidated.

The working principle is as follows: the lower part of the yielding tray on the hollow threaded rod body is embedded into the surrounding rock, the middle part of the yielding sleeve is in a drum shape protruding outwards, two ends of the yielding sleeve are contracted to be horizontal to the rod body, the yielding sleeve is in a cake shape with the length along the direction of the rod body being reduced and the vertical length being increased after being compressed, the spiral spring can be compressed into the cake shape in the stress yielding process, the diameter end and the small diameter end are compressed on the same plane, when the stress and the deformation of the surrounding rock are increased, the spiral spring and the yielding sleeve begin to deform under stress to release the variable performance of the surrounding rock, along with the increase of the stress and the deformation of the surrounding rock, the compression deformation of the spiral spring and the yielding sleeve begins to play a role of the zigzag yielding structure, the yielding device begins to slide relative to the zigzag yielding structure, the bulge of the zigzag yielding structure begins to stress yielding, the bulge sliding to enter the groove at one bulge and then enter the next bulge to realize multi-level yielding, the crescent resistance increasing device and the expandable anchor head increase the friction force between the anchor rod and the surrounding rock, and improve the stability of the surrounding rock; the high-molecular grouting material fills the joint cracks of the surrounding rock, so that the anchoring effect of the anchoring system is enhanced; the water drain holes drain water in the rock-soil body in time, so that the stability of the surrounding rock is further improved.

Has the advantages that: compared with the prior art, the invention has the following remarkable advantages: 1. more variable performance of the surrounding rock can be released, larger deformation can be borne, and the engineering requirement of large deformation of the soft rock tunnel can be met; 2. the joint cracks in the surrounding rock are filled by using the high-molecular grouting material, so that the overall performance and strength of the loose broken rock-soil body are improved after cementation, and the supporting effect is improved; 3. the friction resistance between the yielding anchor rod and the surrounding rock is large, and the stability of the supporting system is high; 4. water in rock and soil bodies can be drained in time, and the stability of surrounding rocks is improved; 5. the tunnel is simple in structure, simple and convenient to install and easy to construct, the tunneling speed of the soft rock engineering tunnel can be improved, the construction period is shortened, and the supporting and maintaining cost of the soft rock engineering is reduced.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a top view of the pressure relief device of the present invention;

FIG. 3 is a cross-sectional view of the resistance increasing device of the present invention connected to a rod;

FIG. 4 is a schematic view of the drain hole arrangement of the present invention

Detailed Description

As shown in fig. 1 to 4, the device comprises a hollow threaded rod body 1 with a coarse thread on the whole body, a pressure yielding device 5 is installed at the upper end of the hollow threaded rod body 1 through a locking device 2, a pressure yielding tray 7 is installed at the lower end of the pressure yielding device 5, an expandable anchor head 9 is installed at the lower end of the hollow threaded rod body 1, a drain hole 10 is arranged on the hollow threaded rod body 1 at the lower part of the pressure yielding tray 7, a resistance increasing device 8 is arranged on the hollow threaded rod body 1 at the lower part of the pressure yielding tray 7, the resistance increasing device 8 is crescent and is made of steel, an upper padding plate 4 is installed between the locking device 2 and the pressure yielding device 5 through a rubber gasket 3, a lower padding plate 6 is installed between the pressure yielding tray 7 and the pressure yielding device 5 through a rubber gasket 3, the pressure yielding device 5 comprises a pressure yielding sleeve 51, a spiral spring 52 installed in the pressure yielding sleeve 51 and a sawtooth, let and press sleeve pipe 51 to be the drum form, helical spring 52 upper portion is the path end, the lower part is big footpath end, wholly be trapezoidal, helical spring 52 can be compressed into the pie at the atress in-process of letting press, footpath end and path end are compressed on the coplanar, 3 helical spring 52 set up on upper padding plate 4 according to equilateral triangle, but expandable anchor head 9 uses sodium acrylate and acrylamide as monomer copolymerization preparation to form, the inside pervious concrete that pours into of the hollow thread body of rod 1, the filter cloth that permeates water of outside parcel.

Before the use, each component of the yielding anchor rod is tested and checked, and the yielding anchor rod is put into use after being tested and checked to be qualified, during use, the corresponding hole section in a tunnel is subjected to advanced grouting and supporting treatment, then an anchor rod drilling machine is used for drilling holes, each component of the yielding anchor rod is subjected to anticorrosive coating treatment, the anchor head expansion resistance-increasing type drainable yielding anchor rod is sent to the bottom of the hole, then grouting materials and pervious concrete are sent, the anchor rod is locked, and finally prestress load is applied.

Claims

1. The utility model provides a but anchor head inflation resistance-increasing drainage multistage lets presses stock, a serial communication port, includes the cavity screw thread body of rod (1), cavity screw thread body of rod (1) upper end is installed through locking device (2) and is let pressure device (5), let pressure device (5) lower extreme install and let and press tray (7), but tip installation expandable anchor head (9) under the cavity screw thread body of rod (1), let be provided with wash port (10) on the cavity screw thread body of rod (1) of pressing tray (7) lower part.

2. The anchor head expansion resistance-increasing type drainable multi-stage yielding anchor rod according to claim 1, wherein a resistance increasing device (8) is arranged on the hollow threaded rod body (1) at the lower part of the yielding tray (7).

3. The anchor head expansion resistance-increasing drainable multi-stage yielding anchor rod as claimed in claim 2, wherein the resistance-increasing device (8) is crescent-shaped and made of steel.

4. The anchor head expansion resistance-increasing type drainable multistage yielding anchor rod according to claim 1, wherein an upper backing plate (4) is installed between the locking device (2) and the yielding device (5) through a rubber gasket (3), and a lower backing plate (6) is installed between the yielding tray (7) and the yielding device (5) through the rubber gasket (3).

5. The anchor head expansion resistance-increasing type drainable multi-stage pressure-yielding anchor rod according to claim 1, wherein the pressure-yielding device (5) comprises a pressure-yielding sleeve (51), a spiral spring (52) installed in the pressure-yielding sleeve (51), and a sawtooth-shaped pressure-yielding structure (53) arranged on the hollow threaded rod body (1).

6. The anchor head expansion resistance-increasing type drainable multi-stage yielding anchor rod as claimed in claim 5, wherein the yielding sleeve (51) is drum-shaped, the upper part of the spiral spring (52) is a small-diameter end, the lower part of the spiral spring is a large-diameter end, the whole body is trapezoidal, and the spiral spring is arranged in an equilateral triangle.

7. The anchor head expansion resistance-increasing drainable multi-stage yielding anchor rod as claimed in claim 1, wherein the hollow threaded rod body (1) is provided with a coarse thread throughout.

8. The anchor head expansion resistance-increasing type drainable multistage yielding anchor rod as claimed in claim 1, wherein the expandable anchor head (9) is prepared by copolymerizing sodium acrylate and acrylamide as monomers.

9. The anchor head expansion resistance-increasing type drainable multi-stage yielding anchor rod as claimed in claim 1, wherein the hollow threaded rod body (1) is internally filled with pervious concrete and externally wrapped with pervious filter cloth.

10. The anchor head expansion resistance-increasing type drainable multistage pressure-yielding anchor rod as claimed in claim 1, wherein an anti-corrosion treatment layer is coated on the anchor head expansion resistance-increasing type drainable multistage pressure-yielding anchor rod, the anti-corrosion treatment layer is an oil-resistant antistatic coating layer and an epoxy resin protective layer, an anchoring section of the anchor head expansion resistance-increasing type drainable multistage pressure-yielding anchor rod in surrounding rock is filled with a high-polymer grouting material, and the high-polymer grouting material is prepared from resin and a catalyst.