CN114810173A

CN114810173A - Self-adaptive yielding anchor rod device and construction method

Info

Publication number: CN114810173A
Application number: CN202210424005.1A
Authority: CN
Inventors: 邢振华; 石准光; 侯波; 刘庆飞; 罗林; 付琨; 付抗; 高佳; 杨虎
Original assignee: Chongqing Jiaotong University; China State Railway Investment Construction Group Co Ltd; China Construction Third Bureau Construction Engineering Co Ltd
Current assignee: Chongqing Jiaotong University; China State Railway Investment Construction Group Co Ltd; China Construction Third Bureau Group Co Ltd
Priority date: 2022-04-21
Filing date: 2022-04-21
Publication date: 2022-07-29

Abstract

The invention discloses a self-adaptive yielding anchor rod device which comprises an anchor rod body, a tray, a yielding device and a pre-tightening nut, wherein the tray, the yielding device and the pre-tightening nut are sleeved on a threaded section at the top of the anchor rod body from bottom to top, high-strength base plates are arranged on the upper side and the lower side of the yielding device respectively, the yielding device comprises replaceable steel pipes with through holes uniformly distributed around the circumference, a damping ring is tightly attached to the inner wall of the yielding device, and an anti-corrosion coating is brushed on the outer wall of the yielding device. The invention also provides a self-adaptive anchor rod construction method, which comprises the following steps: step A, firstly, drilling a hole through a drilling tool, and placing an anchor rod body into the drilled hole; b, fixing the anchor rod body, and then selecting a yielding device according to the impact force generated by the deformation of the rock body; c, successively installing the tray and the yielding device at the thread of the anchor rod body from top to bottom; and D, the yielding device absorbs impact force and then generates compression deformation to realize yielding displacement, and the method has the advantages of good supporting effect, wide applicability, good damping effect, simple construction steps, easiness in operation and the like.

Description

Self-adaptive yielding anchor rod device and construction method

Technical Field

The invention belongs to the technical field of geotechnical engineering anchor rod support, and particularly relates to a self-adaptive yielding anchor rod device and a construction method.

Background

Building tunnel engineering in a weak surrounding rock stratum under a high ground stress environment, wherein the phenomenon of large extrusion deformation of the surrounding rock is easy to occur after excavation; under the conditions of earthquake, impact load, excavation unloading or slope surface loading, rheology, creep and the like, the rock mass of the side slope is easy to generate large deformation. In view of the above-mentioned engineering, if the supporting force is improved by only increasing the size of the supporting anchor member or changing the material of the anchor rod body, not only the supporting cost is increased, but also the problem that the anchor rod is broken and fails can not be solved fundamentally.

The existing yielding anchor rod has the following defects: 1) the pressure relief device has complex factory manufacturing process, inconvenient processing and high cost, and is difficult to be accepted by engineering sites; 2) the initial yielding load cannot be set, and the yielding distance cannot be flexibly adjusted, so that the yielding anchor rod cannot achieve the due supporting effect; 3) the strength of the rod body of the anchor rod is insufficient, and partial projects show that the pressure-yielding anchor rod has the condition that the rod body is broken without starting the pressure-yielding device; 4) the shock-absorbing anchor rod does not have an obvious shock-absorbing function, and the phenomenon of sharp increase of axial force occurs under the action of impact load, so that the anchor rod structure fails.

Disclosure of Invention

The invention aims to provide a self-adaptive yielding anchor rod device and a construction method, which have the advantages of good supporting effect and low manufacturing cost and solve the problems that the existing yielding anchor rod is complex in structure, high in cost and unsatisfactory in supporting effect due to the fact that yielding loads and yielding distances cannot be flexibly adjusted.

Therefore, the technical scheme adopted by the invention is as follows: the utility model provides a self-adaptation lets presses stock device, includes the stock body of rod and from up the tray of suit at stock body of rod top screw thread section down, lets pressure device, pretightening nut, through from last pretensioning nut fixed tray of down screwing and let the pressure device, let the upper and lower both sides of pressure device all be equipped with the backing plate that excels in, let the pressure device include that the circumference equipartition is equipped with the removable steel pipe of through-hole to can let the pressure distance and let the pressure load of pressure device through adjustment steel pipe length, circumference through-hole major and minor axis ratio and trompil parameter adjustment, the major axis is along circumference size, and the minor axis is through-hole along stock body of rod axis direction size, the trompil parameter is single through-hole and divides in order to let the girth of pressure device along the number of the size multiplication through-hole of circumference direction, lets pressure device inner wall hug damping ring, outer wall brush have the anticorrosion coating.

As the optimization of the scheme, the opening parameter range of the through holes around the pressure yielding device is 1% -4%, the opening parameter adjusting range is wide, the opening parameter can be adjusted within a large range to the pressure yielding load, the applicability of the pressure yielding device is wide, and the practicability is high.

Further preferably, the number of the holes formed in the pressure relief device is 3-4, the size of a single hole in the circumferential direction is 4-22 mm, and the range of the hole forming parameters is effectively guaranteed.

Further preferably, the length of the yielding device is 40 mm-50 mm, the size is 60 mm-70 mm in outer diameter and 2mm in wall thickness, and the problem that the length of the yielding device is too long or too short, so that the yielding distance is inconvenient to adjust is avoided.

Further preferably, the ratio of the long axis to the short axis of the circumferential through hole of the yielding device is 1: 2-2: 1, the range of the ratio of the long axis to the short axis is wide, the range of the yielding load can be adjusted, the ratio of the long axis to the short axis of the through hole can be adjusted in a small range, and the yielding load can be adjusted flexibly according to requirements.

Preferably, the pressure yielding device is made of a carbon steel pipe, the damping ring is made of a polyurethane elastic material, and the pressure yielding device has high tensile strength, excellent elasticity, wear resistance, oil resistance and cold resistance and effectively enhances the damping effect of the pressure yielding device; the anti-corrosion coating adopts an epoxy resin coating, has good anti-corrosion performance, and also has strong adhesive force, weather resistance, water resistance, durability and other properties.

Preferably, a resin gasket for buffering is arranged between the high-strength base plate and the tray, so that the high-strength base plate is good in buffering effect and tight in connection.

The invention also provides a self-adaptive anchor rod construction method, which comprises the following steps:

step A, firstly drilling a hole through a drilling tool, adopting the self-adaptive yielding anchor rod device, and firstly placing an anchor rod body matched with the inner diameter of the drilled hole into the drilled hole, wherein the thread section of the anchor rod body is exposed out of the ground;

b, uniformly arranging positioning support frames along the periphery of the anchor rod body, grouting an anchoring agent through a grouting guide pipe, fixing the anchor rod body to be placed into a drilling part, selecting a yielding device meeting requirements of yielding load and yielding distance according to impact force generated by rock deformation, wherein when the tapping parameter is fixed, the yielding load is positively correlated with the ratio of the long axis and the short axis of the through hole, and when the ratio of the long axis and the short axis of the through hole is fixed, the yielding load is negatively correlated with the tapping parameter; the yielding distance is positively correlated with the opening parameters and the length of the yielding device;

c, successively installing the tray and the pressure relief device at the thread of the anchor rod body from top to bottom, enabling the tray to be tightly attached to the ground, and finally screwing and fixing the tray through a pre-tightening nut;

and D, when the rock body deforms to generate impact force, the tray transmits the impact force to the yielding device, and after the yielding device reaches yielding load, the yielding device absorbs the impact force and then generates compression deformation to realize yielding displacement.

The invention has the beneficial effects that:

(1) the yielding device comprises replaceable steel pipes with through holes uniformly distributed on the periphery, the yielding distance and the yielding load of the yielding device can be adjusted by adjusting the length of the steel pipes, the ratio of the length to the minor axis of the through holes on the periphery and the tapping parameters, and compared with a common anchor rod, the load-displacement curve of the self-adaptive yielding anchor rod increases the 'yielding stage' (certain yielding displacement can be generated under the same load to adapt to the deformation of a rock body); the adjustment of the structure form of the yielding device can be used for adjusting yielding load and yielding distance, the self-adaptive yielding anchor rod support effect is good, and the applicability is wide.

(2) Let and press the device inner wall to hug closely and have the shock attenuation ring, the outer wall brush has the anticorrosion coating, guarantees that the self-adaptation lets press the stock device shock attenuation effectual, guarantees to let press the device can not be impaired because of corroding, effectively strengthens letting press device life.

(3) Let the upper and lower both sides of pressure equipment all be equipped with high strength backing plate to increase the atress area of pressure equipment, make the transmission of force more even, effectively increase the steadiness of structure.

(4) When the rock mass warp and produces the impact force, the tray gives the pressure device with impact force transmission, after the pressure device reaches the pressure load of letting, let the pressure device take place compression deformation after absorbing the impact force and realize letting and press the displacement, the construction step is simple easily operated.

In conclusion, the support device has the advantages of good support effect, wide applicability, good damping effect, simple construction steps, easiness in operation and the like, and has a great application prospect.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

Fig. 2 is a schematic structural diagram of the pressure relief device.

Detailed Description

The invention will be further illustrated by the following examples in conjunction with the accompanying drawings:

referring to fig. 1-2, the self-adaptive yielding anchor rod device comprises an anchor rod body 1, a tray 2 sleeved on a threaded section at the top of the anchor rod body 1 from bottom to top, a yielding device 3 and a pre-tightening nut 4.

The tray 2 and the yielding device 3 are fixed by screwing the pretightening nut 4 from top to bottom.

The upper and lower sides of the pressure-yielding device 3 are equipped with high-strength backing plates 31.

The yielding device 3 mainly comprises replaceable steel pipes with through holes uniformly distributed on the periphery, and the yielding distance and the yielding load of the yielding device 3 can be adjusted by adjusting the length of the steel pipes, the ratio of the length to the minor axis of the through holes on the periphery and the opening parameters,

the major axis is the size of the through hole 32 along the circumferential direction, the minor axis is the size of the through hole 32 along the axial direction of the anchor rod body 1, and the opening parameter is the size of a single hole along the circumferential direction multiplied by the number of the through holes 32 to divide the circumference of the yielding device 3.

The opening parameter range of the through holes around the pressure relief device 3 is 1-4%.

The number of the holes formed in the pressure yielding device 3 is 3-4, and the size of a single hole along the circumferential direction of the ring is 4-22 mm.

The length of the pressure device 3 is 40 mm-50 mm, and the size is 60 mm-70 mm of the outer diameter and 2mm of the wall thickness.

The ratio of the long axis to the short axis of the circumferential through hole of the yielding device 3 is 1: 2-2: 1.

Through the preliminary study discovery to the statics characteristic of the self-adaptation pressure-yielding anchor rod: the yielding distance of the yielding device 3 is mainly influenced by the tapping parameter and the length of the yielding device 3, and when one factor is determined, the yielding distance increases along with the increase of the level of the other factor.

In the actual engineering, the yielding device 3 can be adjusted in yielding distance by changing the length and the opening parameters of the yielding device 3, but the opening parameters are adjusted, so that the influence of the opening parameters on yielding load is considered.

The inner wall of the pressure yielding device 3 is tightly attached with a damping ring 33, and the outer wall is brushed with an anti-corrosion coating.

The yielding device 3 is made of a carbon steel pipe, the damping ring 33 is made of a polyurethane elastic material, and the anti-corrosion coating is made of an epoxy resin coating.

A resin gasket 5 for buffering is provided between the high-strength mat 31 and the pallet 2.

A self-adaptive anchor rod construction method comprises the following specific implementation steps:

step A, firstly drilling a hole through a drilling tool, adopting the self-adaptive yielding anchor rod device, and firstly placing the anchor rod body 1 matched with the inner diameter of the drilled hole into the drilled hole, wherein the thread section of the anchor rod body 1 is exposed out of the ground.

And step B, uniformly arranging positioning support frames along the circumference of the anchor rod body 1, and grouting the anchoring agent through a grouting guide pipe, so that the anchor rod body 1 is fixed and placed into a drilling part, and then selecting a yielding device 3 meeting yielding load and yielding distance requirements according to the impact force generated by rock deformation.

When the hole opening parameter is fixed, the yielding load is in positive correlation with the ratio of the long axis to the short axis of the through hole, when the ratio of the long axis to the short axis of the through hole is fixed, the yielding load is in negative correlation with the hole opening parameter, a carbon steel pipe with the length of 40mm and the size of 60mm multiplied by 2mm in wall thickness is selected as the yielding device 3, and when the hole opening parameter is 2.55%, the yielding load of the yielding device 3 can be adjusted to be between 134kN and 148kN by adjusting the ratio of the long axis to the short axis; when the ratio of the long axis to the short axis of the opening is 1:1, namely, the shape of the opening is circular, the yielding load of the yielding device 3 can be adjusted to be between 105kN and 242kN by adjusting the parameters of the opening.

Therefore, when the yielding device 3 is selected in the actual engineering, the yielding load can be adjusted within a larger range by adjusting the hole opening parameters, and the yielding load can be adjusted within a small range by adjusting the ratio of the long axis to the short axis.

Let and press distance and trompil parameter and let 3 lengths of pressure equipment all be positive correlation, experimental data shows: when the hole opening parameter is 2.55%, the test yielding distance of the yielding device 3 with the length of 50mm is 12mm larger than that of the yielding device 3 with the length of 40 mm; when the length of the yielding device 3 is 50mm, the yielding distance of the yielding device 3 with the opening parameter of 1.7 percent is 10mm larger than that of the yielding device 3 with the opening parameter of 3.11 percent.

And the positioning support frame in the step B adopts a tripod support frame.

And step C, successively installing the tray 2 and the yielding device 3 at the thread of the anchor rod body 1 from top to bottom, enabling the tray 2 to be tightly attached to the ground, and finally screwing and fixing the tray through the pre-tightening nut 4.

And D, when the rock body deforms to generate impact force, the tray 2 transmits the impact force to the yielding device 3, and after the yielding device 3 reaches yielding load, the yielding device 3 absorbs the impact force and then generates compression deformation to realize yielding displacement.

Claims

1. A self-adaptive pressure-giving anchor rod device, comprising a rock-bolt rod body (1), a tray (2) sleeved on the threaded section at the top of the rock-bolt rod body (1) from bottom to top, a pressure-giving device (3), a pre-tightening Nut (4), by tightening the pre-tightening nut (4) from top to bottom to fix the tray (2) and the pressure letting device (3), it is characterized in that: the upper and lower sides of the pressure letting device (3) are equipped with The high-strength backing plate (31), the pressure letting device (3) includes a replaceable steel pipe with through holes (32) evenly distributed around the circumference, and can be adjusted by adjusting the length of the steel pipe, the ratio of the length and the short axis of the circumferential through holes and the opening parameters The yielding distance and yielding load of the yielding device (3), the long axis is the dimension of the through hole (32) along the circumferential direction of the ring, and the short axis is the dimension of the through hole (32) along the axis of the bolt body (1), The opening parameter is the size of a single through hole (32) along the circumference of the ring multiplied by the number of through holes (32) divided by the perimeter of the pressing device (3), so that the inner wall of the pressing device (3) is in close contact with the inner wall of the pressing device (3). There is a shock-absorbing ring (33), and the outer wall is brushed with an anti-corrosion coating.

2 . The self-adaptive pressure yielding anchor rod device according to claim 1 , wherein the opening parameters of the peripheral through holes of the pressure yielding device (3) range from 1% to 4%. 3 .

3 . The self-adaptive pressure-yielding bolt device according to claim 2 , wherein the number of openings of the pressure-yielding device (3) is 3 to 4, and the size of a single hole along the circumference of the ring is 3. 4 . 4mm～22mm.

4 . The self-adaptive pressure yielding bolt device according to claim 1 , wherein the pressure yielding device ( 3 ) has a length of 40 mm to 50 mm, and a size of an outer diameter of 60 mm to 70 mm × a wall thickness of 2 mm. 5 .

5 . The self-adaptive pressure yielding anchor rod device according to claim 1 , wherein the ratio of the major and short axes of the circumferential through holes of the pressure yielding device ( 3 ) is 1:2 to 2:1. 6 .

6. The self-adaptive pressure yielding bolt device according to claim 1, characterized in that: the pressure yielding device (3) is made of carbon steel pipe, and the shock absorbing ring (33) is made of polyurethane elastic material, so The anti-corrosion coating adopts epoxy resin coating.

7 . The self-adaptive pressure yielding bolt device according to claim 1 , wherein a resin washer ( 5 ) for buffering is provided between the high-strength backing plate ( 31 ) and the tray ( 2 ). 8 .

8. A self-adaptive anchor construction method, characterized in that, comprising the following steps:

Step A, first drill through the drilling tool, adopt a kind of self-adaptive pressure bolt device according to any one of claims 1-7, and first place the bolt body (1) matching the inner diameter of the hole into the Inside the drilled hole, but the threaded section of the bolt body (1) is exposed to the ground;

Step B, the positioning support frame is evenly distributed along the circumference of the bolt body (1), and the anchoring agent is grouted through the grouting conduit, so as to fix the bolt body (1) into the drilled part, and then deform according to the rock mass When the impact force is generated, select the pressure-yielding device (3) that meets the requirements of the pressure-yielding load and the pressure-yielding distance. When the opening parameters are fixed, the pressure-loading load is positively correlated with the ratio of the length and the minor axis of the through hole. When the ratio of the length and the minor axis of the through hole is fixed, let The pressure load is negatively correlated with the opening parameters; the pressure yielding distance is positively correlated with the opening parameters and the length of the pressure yielding device (3);

Step C. Install the tray (2) and the pressure letting device (3) on the thread of the anchor rod body (1) from top to bottom, and the tray (2) is close to the ground, and finally tightened by the pre-tightening nut (4). fixed;

Step D. When the rock mass is deformed to generate impact force, the tray (2) transmits the impact force to the pressure letting device (3), and when the pressure letting device (3) reaches the let pressure load, the pressure letting device (3) absorbs the impact force After the compression deformation occurs, the yielding displacement is realized.