CN113217053A

CN113217053A - Self-adaptive large-deformation prestressed anchor rod

Info

Publication number: CN113217053A
Application number: CN202110533072.2A
Authority: CN
Inventors: 梅岭; 王雷; 董鑫
Original assignee: Jiangsu University of Science and Technology
Current assignee: Jiangsu University of Science and Technology
Priority date: 2021-05-14
Filing date: 2021-05-14
Publication date: 2021-08-06

Abstract

The invention discloses a self-adaptive large-deformation prestressed anchor rod which comprises a first hollow rod body, a first baffle plate, a spring, a second baffle plate and a second hollow rod body, wherein the first hollow rod body and the second hollow rod body extend out of a sleeve, the first baffle plate, the spring and the second baffle plate are arranged in the sleeve, one end of the spring is connected with the first hollow rod body through the first baffle plate, the other end of the spring is connected with the second hollow rod body through the second baffle plate, a pipeline penetrates through the spring and is communicated with the first hollow rod body and the second hollow rod body, and the second hollow rod body is communicated with an air bag. The invention can meet the requirement of support strength, continuously ensure the support quality under the condition of large deformation of surrounding rocks, improve the elongation of the anchor rod, increase the elongation of the anchor rod, play an effective role in buffering and treatment and ensure the safety of the support environment; when the surrounding rock generates large impact load, the spring is gradually pulled away under the action of tension, the resin material keeps absorbing energy, the anchor rod is ensured to be slowly deformed, a complete force transmission area is kept, and the high efficiency and the safety of the anchor rod are ensured.

Description

Self-adaptive large-deformation prestressed anchor rod

Technical Field

The invention belongs to anchor rods, and particularly relates to a self-adaptive large-deformation prestressed anchor rod.

Background

The anchor rod is used as a rod piece system structure for anchoring rock and soil mass, and is commonly used in reinforcing engineering such as rock and soil slope support, foundation pit support, tunnel support and the like in engineering technology. The rock-soil body is easy to generate slope damage due to low tensile strength, and the anchor rod has good longitudinal tensile strength and can overcome the defect of weak tensile strength of the rock body after forming a new compound with the rock-soil body. The anchor bolt support is characterized in that the mechanical state of surrounding rock is changed through an anchor bolt in the surrounding rock, an integral and stable rock zone is formed around a roadway, and the purpose of maintaining stability of the roadway is achieved by utilizing the combined action of the anchor bolt and the surrounding rock, so that the bearing capacity of a rock-soil body is greatly enhanced.

Although the anchor rod has good supporting effect and simple construction, the traditional anchor rod is easy to deform and break under the limit stress due to the low elongation of the anchor rod when the traditional anchor rod is subjected to surrounding rock deformation, rock deep layer fracture deformation or impact load (such as earthquake action or rock burst), so that an anchor rod supporting system fails. The allowable deformation of the traditional anchor rod is generally below 200mm, the geological environment becomes more complex along with the increase of the underground construction depth, the phenomenon of large deformation caused by the breakage of deep rock masses often occurs in the construction process of deep foundation pit engineering and tunnel engineering, various safety accidents caused by the large deformation and the damage of the rock masses occur sometimes, and the support technology based on the common anchor rod cannot adapt to the large deformation of surrounding rocks to cause the failure of a support system.

Aiming at the problem that the existing anchor rod is not suitable for large deformation of surrounding rock, a novel anchor rod supporting method needs to be designed, so that the requirement on supporting strength is met, and meanwhile, the supporting quality is guaranteed continuously under the condition of large deformation of the surrounding rock.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the defects in the prior art, the invention aims to provide the self-adaptive large-deformation prestressed anchor rod which can improve the elongation rate of the anchor rod, increase the elongation of the anchor rod and ensure the safety of a supporting environment.

The technical scheme is as follows: the invention relates to a self-adaptive large-deformation prestressed anchor rod which comprises a first hollow rod body, a first baffle plate, a spring, a second baffle plate and a second hollow rod body, wherein the first hollow rod body and the second hollow rod body extend out of a sleeve, the first baffle plate, the spring and the second baffle plate are arranged in the sleeve, one end of the spring is connected with the first hollow rod body through the first baffle plate, the other end of the spring is connected with the second hollow rod body through the second baffle plate, a pipeline penetrates through the spring and is communicated with the first hollow rod body and the second hollow rod body, and the second hollow rod body is communicated with an air bag. The anchor rod can provide constant constraint force by being stretched by the compression of the high-strength spring so as to adapt to the deformation of the surrounding rock or convert the energy generated by deep impact load into the elastic potential energy of the spring, ensure that the anchor rod does not lose efficacy instantly under the limit stress state, increase the elongation of the anchor rod, effectively buffer the energy generated by the deformation or impact load of the surrounding rock, stabilize the surrounding rock for a long time and have good supporting effect.

Furthermore, two ends of the sleeve are provided with sealing covers, and the sealing covers are pressed tightly through bolts. The space formed by enclosing the sleeve, the sealing cover, the first baffle, the second baffle, the first hollow rod body and the second hollow rod body is filled with resin materials. The resin material is epoxy resin, and the resin material can keep the energy absorption state, makes the stock slowly warp, keeps complete biography power region, ensures the high efficiency and the security of stock.

Further, the first hollow rod body is connected with the tray, and the tray is pressed tightly through the nut. The tray is tightly attached to the surrounding rock wall.

Further, the outer diameter of the spring is equal to the inner diameter of the sleeve. The spring has an elastic modulus of 200MPa or more, and preferably a 65Mn high-strength spring. And a strain gauge for measuring the stress value is attached to the outer side of the spring, the strain gauge is connected with the controller and the alarm, and when the stress value measured by the strain gauge is larger than the designed value, the controller gives an alarm.

Furthermore, one end of the hollow rod body II is provided with an external thread, the air bag is provided with an inflation inlet, the inner side of the inflation inlet is provided with an internal thread, the external thread is matched with the internal thread, the air bag part is a prefabricated part, the on-site assembly and the transportation are convenient, and the damaged part or the damaged air bag can be replaced. Meanwhile, the surface of the air bag is provided with a plurality of spherical protrusions, so that the contact area with a rock body can be increased after grouting, the friction force is increased, and the anchoring force of the anchor rod is increased.

The working principle is as follows: after the drilling and grouting are completed for prestress tensioning, when the surrounding rock is slightly deformed, the meshing of the threads on the outer wall of the sleeve, the threads of the anchor rod and the slurry can share the tension of the anchor rod to achieve the supporting effect. The air bag part arranged at the end part of the anchor rod can expand in volume after grouting to form a large-head anchor rod, and the spherical bulge arranged on the surface can further increase the pulling resistance of the anchor rod. When the surrounding rock generates larger deformation or rock burst and other larger impact loads occur in the deep layer of the supporting structure, the first hollow rod body and the second hollow rod body move away. Under the action of the pulling force, the high-strength spring is gradually pulled apart. In the process that the spring is pulled away, the resin material keeps an energy absorption state all the time, the anchor rod is guaranteed to deform slowly, a complete force transmission area is kept continuously, and the high efficiency and the safety of an anchor rod supporting system are guaranteed.

Has the advantages that: compared with the prior art, the invention has the following remarkable characteristics:

1. the requirement on the supporting strength can be met, the supporting quality can be continuously guaranteed under the condition of large deformation of surrounding rocks, the elongation of the anchor rod is improved, the elongation of the anchor rod is increased, effective buffering and treatment effects can be achieved on sudden disasters such as tunnel rock burst and coal mine rock burst, and the supporting environmental safety can be guaranteed;

2. when the surrounding rock has large impact load, under the action of tension, in the process that the spring is gradually pulled away, the resin material keeps absorbing energy, so that the anchor rod is ensured to be slowly deformed, a complete force transmission area can be continuously kept, and the high efficiency and the safety of an anchor rod supporting system are ensured;

3. the prefabricated component air bag is arranged, field assembly and transportation are facilitated, and the component or the air bag can be replaced when damaged. The size of the anchor rod can be expanded to form a large-head anchor rod after drilling and grouting, the contact area between the end part of the anchor rod and a rock body can be increased by the spherical protrusions arranged on the surface of the anchor rod, the friction force is increased, and the anti-pulling force of the anchor rod is further increased;

4. the high-strength spring in the sleeve is pasted with the strain gauge that is used for measuring the spring and produces the meeting an emergency when tensile, and the strain gauge other end is connected with controller and alarm, and the controller adopts solar cell, is provided with the display on the controller, can look over the real-time stress value of spring that the strain value that is measured by the strain gauge calculated, if when the strain gauge measured the stress value and is greater than the design value, the controller produced current, connect the alarm and produce the early warning, play side slope protection early warning effect, the security improves.

Drawings

FIG. 1 is a cross-sectional view of a first operational state of the present invention;

FIG. 2 is a cross-sectional view of a second operational state of the present invention;

FIG. 3 is an enlarged view of a portion of the bladder 8 of the present invention;

fig. 4 is a partially enlarged view of the strain gauge 13 of the present invention.

Detailed Description

The directions shown in the drawings of the specification are up, down, left and right.

As shown in figure 1, a hollow rod body I1 of the self-adaptive large-deformation prestressed anchor rod is fixedly connected with a tray 11 through threads, and the tray 11 is tightly pressed through a nut 12 and tightly attached to a surrounding rock wall. Two ends of the sleeve 6 are provided with sealing covers 9 which are respectively fixedly connected with the hollow rod body I1 and the hollow rod body II 5 through bolts 10. The hollow rod body I1 and the hollow rod body II 5 are arranged in parallel relatively. One end of the spring 3 is fixedly connected with the first hollow rod body 1 through the first baffle plate 2, and the other end of the spring is fixedly connected with the second hollow rod body 5 through the second baffle plate 4. The hollow rod body II 5 is fixedly connected with the air bag 8 through threads. The space enclosed by the sleeve 6, the sealing cover 9, the baffle I2, the baffle II 4, the hollow rod I1 and the hollow rod II 5 is filled with resin material 15. The resin material 15 is epoxy resin, and the resin material 15 can keep an energy absorption state, so that the anchor rod is slowly deformed, a complete force transmission area is kept, and the high efficiency and the safety of the anchor rod are ensured. When the surrounding rock is slightly deformed, the meshing of the outer wall threads of the sleeve 6, the anchor rod threads and the slurry can share the tensile force of the anchor rod to achieve the supporting effect.

As shown in fig. 2, after the sleeve 6 is installed, grouting and prestress tension are performed, grouting is performed through the hollow rod body one 1, the pipeline 7 and the hollow rod body two 5, and grout is filled in the air bag 8. And then the air bag 8 gradually expands due to elasticity to form an expanded head anchor rod, so that the pulling resistance of the anchor rod is increased. The air bag 8 is vulcanized by synthetic rubber and high-strength fiber cloth, has good expansion resistance, elasticity and flexibility, and can meet the requirements of construction under various working conditions. The surface of the air bag 8 is provided with a plurality of spherical bulges, so that the contact area with a rock body can be increased, the friction force is increased, and the anchoring capability of the anchor head is further increased. When the surrounding rock generates larger deformation or rock burst and other larger impact loads occur in the deep layer of the supporting structure, the hollow rod body I1 and the hollow rod body II 5 move away from each other. Under the action of the pulling force, the high-strength spring 3 will be gradually pulled apart. In the process that the spring 3 is pulled away, the resin material 15 keeps an energy absorption state all the time, the anchor rod is ensured to deform slowly, a complete force transmission area is kept continuously, and the high efficiency and the safety of an anchor rod supporting system are ensured.

As shown in fig. 3, an external thread is provided at one end of the hollow rod body two 5, an inflation inlet 14 is provided on the air bag 8, an internal thread is provided at the inner side of the inflation inlet 14, the external thread is matched with the internal thread, and the hollow rod body two 5 and the air bag 8 are fixedly connected by the thread, and are tightly connected without air leakage.

As shown in fig. 4, the spring 3 has a central tube 7 for providing a communication passage between the first hollow rod 1 and the second hollow rod 5. The outside of spring 3 is pasted and is used for measuring the foil gage 13 of the strain value that produces when spring 3 stretches, and foil gage 13 links to each other with controller, alarm, and the controller adopts solar cell, is provided with the display on the controller, can look over the real-time stress value of spring 3 that the strain value that measures by foil gage 13 calculated. When the stress value measured and calculated through the strain gauge 13 is larger than the design value, the controller generates control current and is connected with an alarm to generate early warning. Play the side slope protection early warning effect, improve the security. The outer diameter of the spring 3 is equal to the inner diameter of the sleeve 6. The spring 3 has an elastic modulus of 200MPa or more, and preferably a 65Mn high-strength spring 3.

The specific construction method of the self-adaptive large-deformation prestressed anchor rod comprises the following steps of:

a. when the anchor rod is installed, drilling is firstly carried out, and the size of an anchor hole can ensure that the sleeve 6 normally enters the rock body;

b. the combined anchor rod structure is characterized in that the air bag 8 in a natural state is connected with the tail of the anchor rod, the sleeve 6 is connected, and the resin material 15 is added, so that a good closed space is provided for the sleeve 6, the installation is convenient, and meanwhile, the phenomenon that slurry permeates into the sleeve 6 during construction grouting to influence the work of the high-strength spring 3 can be prevented;

c. installing a sealing plate, and fixedly connecting the sealing plate through a bolt 10;

d. the strain gauge 13 is placed on the tray 11 through the slit in the prepared thimble 6. From the equation σ ═ ε × E, the elastic modulus of the spring 3 is known, and from the measured strain, the stress of the spring 3 can be calculated, and the anchor state can be known.

Claims

1. The utility model provides a big deformation prestressed anchorage pole of self-adaptation which characterized in that: including the cavity body of rod (1), the baffle (2), spring (3), the baffle two (4) and the cavity body of rod two (5), the sleeve (6) is stretched out to the cavity body of rod (1), the cavity body of rod two (5), baffle (2), spring (3), baffle two (4) set up in sleeve (6), the one end of spring (3) is passed through baffle one (2) and is linked to each other with the cavity body of rod one (1), and the other end passes through baffle two (4) and links to each other with the cavity body of rod two (5), pass pipeline (7) in spring (3), pipeline (7) and the cavity body of rod one (1), cavity body of rod two (5) looks UNICOM, cavity body of rod two (5) and gasbag (8) looks UNICOM.

2. The self-adaptive large-deformation prestressed anchor rod as claimed in claim 1, wherein: two ends of the sleeve (6) are provided with sealing covers (9), and the sealing covers (9) are pressed tightly through bolts (10).

3. The self-adaptive large-deformation prestressed anchor rod as claimed in claim 2, wherein: and a space formed by enclosing the sleeve (6), the sealing cover (9), the baffle I (2), the baffle II (4), the hollow rod I (1) and the hollow rod II (5) is filled with a resin material (15).

4. The self-adaptive large-deformation prestressed anchor rod as claimed in claim 3, wherein: the resin material (15) is epoxy resin.

5. The self-adaptive large-deformation prestressed anchor rod as claimed in claim 1, wherein: the hollow rod body I (1) is connected with the tray (11), and the tray (11) is pressed through the nut (12).

6. The self-adaptive large-deformation prestressed anchor rod as claimed in claim 5, wherein: the tray (11) is tightly attached to the surrounding rock wall.

7. The self-adaptive large-deformation prestressed anchor rod as claimed in claim 1, wherein: the outer diameter of the spring (3) is equal to the inner diameter of the sleeve (6).

8. The self-adaptive large-deformation prestressed anchor rod as claimed in claim 1, wherein: the elastic modulus of the spring (3) is more than 200 MPa.

9. The self-adaptive large-deformation prestressed anchor rod as claimed in claim 1, wherein: and a strain gage (13) for measuring a stress value is attached to the outer side of the spring (3), and the strain gage (13) is connected with a controller and an alarm.

10. The self-adaptive large-deformation prestressed anchor rod as claimed in claim 1, wherein: one end of the hollow rod body II (5) is provided with an external thread, the air bag (8) is provided with an inflation inlet (14), the inner side of the inflation inlet (14) is provided with an internal thread, and the external thread is matched with the internal thread.