CN116791603A

CN116791603A - Recyclable FRP anchor rod with expansion anchor head and construction method

Info

Publication number: CN116791603A
Application number: CN202310932329.0A
Authority: CN
Inventors: 殷杰; 朱孟传
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2023-07-27
Filing date: 2023-07-27
Publication date: 2023-09-22

Abstract

The invention discloses a recoverable FRP anchor rod with an expandable anchor head and a construction method, and relates to the technical field of civil engineering, wherein the recoverable FRP anchor rod comprises an expandable anchor head, a winding FRP rod body and an anchor; one end of the winding FRP rod body is arranged in the expandable anchor head, and the other end of the winding FRP rod body is arranged in the anchor. The invention solves the problems of longer grouting body age, unrecoverable anchor rod, serious material waste, underground space pollution and the like in the prior art. The invention does not need grouting in the use process, so that the construction period can be shortened. The anchor rod can be reused after being recovered, and the construction cost is reduced.

Description

Recyclable FRP anchor rod with expansion anchor head and construction method

Technical Field

The invention relates to the technical field of civil engineering, in particular to a recyclable FRP anchor rod with an expansion anchor head and a construction method.

Background

In deep foundation pit, side slope support, coal mine, tunnel, etc., a large number of anchor rods are typically required to strengthen the rock-soil body. These anchors are of temporary construction and are designed for use for a period of no more than 24 months. However, due to the high recovery cost of the conventional anchor rods, most anchor rods are left in the rock soil body, and cost waste is caused. In addition, the unrecovered steel anchor rod can also cause interference to the development of the follow-up engineering around, and long-time steel reinforcement corrosion can also cause soil pollution.

Fiber reinforced polymer (Fiber Reinforced Polymer, FRP) materials have been widely used as alternatives to steel anchors. FRP is used as a high-performance nonmetallic composite material, and is a novel high-performance material formed by mixing fiber materials and matrix materials according to a certain proportion and compounding by a certain process. The FRP material can effectively solve the problem of steel corrosion, but the traditional mechanical anchoring and bonding anchoring means can not fully exert the strength. In addition, FRP materials are expensive to market, and so there is a need to find efficient recovery methods to reduce overall costs.

Disclosure of Invention

Aiming at the defects existing in the prior art, the invention provides a recyclable FRP anchor rod with an expansion anchor head and a construction method, and solves the problems of long grouting age, unrecoverable anchor rod, serious material waste and underground space pollution in the prior art.

The present invention achieves the above technical object by the following means.

A recoverable winding type FRP anchor rod structure comprises an expandable anchor head, a winding type FRP rod body and an anchor; one end of the winding FRP rod body is arranged in the expandable anchor head, and the other end of the winding FRP rod body is arranged in the anchor;

the expandable anchor head comprises an inner sleeve, an auxiliary support, a first spring, an outer sleeve and a lock catch; the inner sleeve is arranged in the outer sleeve, one end of a first spring is connected to the bottom surface of the inner sleeve, and the other end of the first spring is connected to the bottom of the outer sleeve;

the inner sleeve is provided with a sleeve which is matched with the winding FRP rod body, the inner sleeve is also connected with a plurality of auxiliary branches through a rotating shaft, and the auxiliary branches radiate to the periphery around the sleeve as a center; the auxiliary support is provided with a through hole;

the lock catch is connected with the outer sleeve through a pin shaft, and the middle section of the lock catch is connected with the side wall of the outer sleeve through a second spring; the lock catches are arranged in one-to-one correspondence with the auxiliary supports, the tail ends of the lock catches are contacted with the auxiliary supports in the inserting process of the winding type FRP rod body, and the tail ends of the lock catches are inserted into the through holes in the recovering process of the winding type FRP rod body.

In the scheme, the inner sleeve is also provided with a rubber block, and the rubber block is arranged between the auxiliary support and the sleeve; in the inserting process of the winding FRP rod body, the rubber block is attached and compressed.

In the scheme, under the condition of no external force, the auxiliary contact rubber block and the axis of the sleeve form an included angle of 30 degrees.

In the scheme, the lock catch is of a rod-shaped structure, and the tail end of the lock catch is provided with the telescopic protruding block.

In the scheme, the anchorage comprises a fixed table, an expanded tenon block and a counter-force table; the expansion tenon block is matched with the winding FRP rod body, one end of the expansion tenon block is arranged in the counter-force table, and the other end of the expansion tenon block is fixed through the fixed table; the constraint block is arranged in the counter-force table and is arranged at the outer side of the expansion tenon block.

In the scheme, the inner side walls of the sleeve and the expansion tenon block are respectively provided with an inner thread, and the inner threads are matched with the outer threads on the winding FRP rod body.

In the scheme, the outer side wall of the winding type FRP rod body is coated with lubricating oil or sleeved with a plastic film.

In the scheme, the number of the first springs is four, and the first springs are uniformly distributed.

In the scheme, the rubber block is of an oval structure.

The construction method of the recyclable winding type FRP anchor rod structure comprises the following steps:

construction of the expandable anchor head: the winding type FRP rod body is combined with the expandable anchor head, inserted into the drill hole, extruded by soil body to reduce the rotation angle, and after reaching a preset position, the winding type FRP rod body is pulled, expanded by the thrust of the rubber block and gradually meshed with the soil body, so as to provide anchoring force for the winding type FRP rod body;

recovering the winding type FRP rod body: the external anchorage device is removed, then the winding type FRP rod body is continuously inserted into the drilling hole, the through hole reaches the position of the lock catch in the process that the inner sleeve compresses the first spring, the lock catch is inserted into the through hole under the action of the restoring force of the second spring (8), the auxiliary support is limited to expand outwards, and accordingly the winding type FRP rod body is pulled out of the drilling hole, and recovery is achieved.

The beneficial effects are that: the invention has simple structure and can be normally used in various complex working conditions. The rod body adopts a winding FRP rod, and has excellent performances such as high strength, corrosion resistance and the like. The anchor head is provided with four auxiliary branches, and the auxiliary branches expand and are engaged with soil body in the use process, so as to provide anchoring force for the anchor rod. After the external anchorage is released, the rod body is pressed towards the drilling hole, at the moment, the spring is compressed, the auxiliary support is folded at the edge of the rod body, and then the lock catch locks the auxiliary support, so that the whole recovery of the anchor rod is completed. Grouting is not needed in the use process, so that the construction period can be shortened. The anchor rod can be reused after being recovered, and the construction cost is reduced.

Drawings

FIG. 1 is a schematic view of a construction of a recoverable FRP bolt having an expandable anchor head in accordance with an embodiment of the present invention;

FIG. 2 is a schematic illustration of the mating of the expandable anchor head and wrapped FRP shank of the type referred to in FIG. 1;

fig. 3 is a schematic view of the engagement of the wrapped FRP rod and anchor as referred to in fig. 1.

Reference numerals:

1-an inner sleeve; 2-attaching branches; 3-rubber blocks; 4-winding FRP rod bodies; 5-a first spring; 6-an outer sleeve; 7-locking; 8-a second spring; 9-through holes; 10-sleeve; 11-a fixed table; 12-expanding tenon blocks; 13-a constraint block; 14-reaction table.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

In the description of the present invention, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present invention and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

A recoverable winding type FRP anchor rod structure comprises an expandable anchor head, a winding type FRP rod body 4 and an anchor; one end of the winding FRP rod body 4 is arranged in the expandable anchor head, and the other end is arranged in the anchor;

the expandable anchor head comprises an inner sleeve 1, an auxiliary support 2, a first spring 5, an outer sleeve 6 and a lock catch 7; the inner sleeve 1 is arranged in the outer sleeve 6, one end of a first spring 5 is connected to the bottom surface of the inner sleeve 1, and the other end of the first spring 5 is connected to the bottom of the outer sleeve 6;

the inner sleeve 1 is provided with a sleeve 10, the sleeve 10 is matched with the winding FRP rod body 4, the inner sleeve 1 is also connected with a plurality of auxiliary supports 2 through a rotating shaft, and the auxiliary supports 2 radiate around by taking the sleeve 10 as the center; the auxiliary support 2 is provided with a through hole 9;

the lock catch 7 is connected with the outer sleeve 6 through a pin shaft, and the middle section of the lock catch 7 is connected with the side wall of the outer sleeve 6 through a second spring 8; the lock catches 7 are arranged in one-to-one correspondence with the auxiliary support 2, the tail ends of the lock catches 7 are in contact with the auxiliary support 2 in the inserting process of the winding type FRP rod body 4, and the tail ends of the lock catches 7 are inserted into the through holes 9 in the recycling process of the winding type FRP rod body 4.

In the above scheme, the inner sleeve 1 is further provided with a rubber block 3, and the rubber block 3 is arranged between the auxiliary support 2 and the sleeve 10; in the process of inserting the winding FRP rod body 4, the rubber block 3 is compressed by the auxiliary support 2.

In the scheme, under the condition of no external force, the auxiliary support 2 contacts the rubber block 3 and forms an included angle of 30 degrees with the axis of the sleeve 10.

In the above scheme, the lock catch 7 has a rod-shaped structure, and a telescopic bump is arranged at the tail end of the lock catch 7.

In the scheme, the anchorage comprises a fixed table 11, an expanded tenon block 12 and a counter-force table 14; the expansion tenon block 12 is matched with the winding FRP rod body 4, one end of the expansion tenon block 12 is arranged in the counter-force table 14, and the other end of the expansion tenon block is fixed through the fixing table 11; the restraint block 13 is disposed within the reaction block 14 and outside the spread tenon block 12.

In the above scheme, the inner side walls of the sleeve 10 and the expanded tenon block 12 are provided with internal threads, and the internal threads are matched with external threads on the winding FRP rod body 4.

In the scheme, the outer side wall of the winding type FRP rod body 4 is coated with lubricating oil or sleeved with a plastic film.

In the above scheme, the number of the first springs 5 is four, and the first springs are uniformly distributed.

In the above scheme, the rubber block 3 has an oval structure.

construction of the expandable anchor head: the winding type FRP rod body 4 is combined with the expandable anchor head, is inserted into a drill hole, the auxiliary support 2 is extruded by soil body to reduce the rotation angle, after reaching a preset position, the winding type FRP rod body 4 is pulled, the auxiliary support 4 is expanded by the thrust of the rubber block 3 and gradually bites into the soil body, and an anchoring force is provided for the winding type FRP rod body 4;

recovering the winding type FRP rod body 4: the external anchorage is removed, then the winding type FRP rod body 4 is continuously inserted into the drilling hole, the through hole 9 reaches the position of the lock catch 7 in the process that the inner sleeve 1 compresses the first spring 5, the lock catch 7 is inserted into the through hole 9 under the action of the restoring force of the second spring 8, the auxiliary support 2 is limited to expand outwards, and accordingly the winding type FRP rod body 4 is pulled out of the drilling hole, and recovery is achieved.

A recoverable FRP anchor rod with an expansion anchor head comprises an expandable anchor head, a winding FRP rod body 4 and an anchor. The anchor head is provided with an auxiliary support 2, and the auxiliary support 2 is in a furled state under the pressure of a rock-soil body when the winding type FRP rod body 4 is inserted into a borehole. When reaching the preset position, the winding FRP rod body 4 is pulled backwards, the auxiliary support 2 is expanded under the action of the rubber block 3 and meshed with the rock-soil body, and anchoring force is provided.

The auxiliary support 2 can be folded by moving towards the inside of the drilling hole again, and the lock catch 7 slides into the through hole 9 of the auxiliary support 2, so that the auxiliary support state is locked.

The expanded mortise and tenon joint 12 in direct contact with the winding type FRP rod body 4 and the sleeve 10 are internally provided with threads, the threads can enable the winding type FRP rod body 4 to be mechanically anchored, and meanwhile, glue can be injected into gaps in the threads, so that the anchoring strength of the winding type FRP rod body is increased.

A construction method of a recoverable stretching expansion head anchor rod structure comprises the following steps:

construction of the expandable anchor head: the winding FRP rod body 4 is combined with the expandable anchor head and is inserted into the drilled hole. The auxiliary support 2 is extruded by soil body to reduce the rotation angle. After reaching the preset position, drawing the winding FRP rod body 4, expanding the auxiliary support 2 by the thrust of the rubber block 3, and gradually engaging with soil to provide anchoring force for the anchor rod;

Examples

The invention provides a recoverable winding type FRP anchor rod with an expansion type anchor head, which solves the problems of longer grouting body age, unrecoverable anchor rod, serious material waste, underground space pollution and the like in the prior art.

The invention can be split into two parts. The first part is an anchor head which can be expanded by stretching and comprises an inner sleeve 1, an auxiliary support 2, rubber 3, an outer sleeve 6, a lock catch 7, a first spring 5, a second spring 8 and a sleeve 10; the second part is a rod body and an anchorage device, and comprises a winding FRP rod body 4, a fixing table 11, an expanded mortise and tenon 12, a constraint block 13 and a counterforce table 14.

The appendage 2 is connected to the inner sleeve 1 and can rotate between 5 ° and 80 ° without taking the rubber block 2 into account. The rubber block 3 is attached to the inner sleeve 1 by bonding. In the state without external force, the contact rubber block 3 of the auxiliary support 2 forms an included angle of 30 degrees with the central shaft.

The first springs 5 are four independent elements and are distributed in a central symmetry mode. Is connected with the inner sleeve 1 and the outer sleeve 5.

The shackle 7 is free to rotate and is restrained during use by a second spring 8.

The auxiliary support 2 and the rubber block 3 are four independent elements and are uniformly distributed in a central symmetry manner.

The sleeve 10 and the expanded mortise and tenon 12 are internally provided with special threads, the thread shape is relatively attached to the surface shape of the winding FRP rod body 4, and special mechanical anchoring can be formed between the thread shape and the winding FRP rod body. Glue can be injected between the screw thread and the rod body according to engineering requirements, so that the anchoring strength of the rod body is increased.

The reaction table 14 is formed by casting concrete in situ, and is connected with the fixing table 11 through nuts. The expanded mortise and tenon 12 and the constraint block 13 can be in sliding contact constraint in the reverse direction along the drilling direction.

The rod body 4 is combined with the anchor head through clockwise rotation of threads, and the bonding strength is enhanced through glue injection.

The rod body 4 and the sleeve 10 are combined and inserted into the drill hole, at the moment, the auxiliary support 2 is extruded by soil body to reduce the rotation angle, and the rubber block 3 is compressed.

After reaching the designated depth, the winding FRP rod body 4 is pulled outwards, and the auxiliary support 2 has a tendency to expand the rotation angle due to the outward acting force of the rubber block 3, so that the auxiliary support is inserted into surrounding soil, and the rotation angle is gradually expanded along with the increase of the pulling distance.

The rubber block 3 is only connected to the inner sleeve 1, so that only an outward force is applied to the auxiliary support 2, and the rubber block 3 will separate from the auxiliary support 2 without acting any more after the rotation angle of the auxiliary support 2 is more than 30 °.

The external shape of the inner sleeve 1 has a limit on the angle of rotation of the appendage 2, which will touch the upper edge of the inner sleeve 1 when the appendage 2 reaches 80 ° and thus cannot continue to expand the angle. The optimal maximum angle can be determined according to experiments and actual working conditions, so that corresponding adjustment is performed.

Before use, it is necessary to apply lubricating oil or to cover a plastic film on the integrally wound FRP rod body 4 in order to reduce friction with the rock-soil body when recovering the rod body.

And after fixing the anchor head and the winding FRP rod body 4, arranging external anchors. The reaction table 14 is formed by pouring concrete, and an internally embedded internally threaded pipe, and the specific shape and the specific size are determined by actual engineering requirements. The expanded mortise and tenon joint 12 is connected with the rod body 4 and is subjected to glue injection reinforcement. Then, the restraint block 13 is inserted, and finally, the fixing base 11 is fixed to the reaction base 14 by a nut.

The fixed table 11 needs to be removed by rotating the screw first and then the restraint block 13 is pulled out. Then the winding type FRP rod body 4 is continuously inserted into the drilling hole, at the moment, the second spring 8 is compressed, the lock catch 9 is inserted into the hole 10, the outward expansion of the auxiliary support 2 is limited, and then the whole winding type FRP rod body 4 can be pulled out of the drilling hole, so that recovery is realized.

The force provided by the engagement of the auxiliary support 2 and the soil body can reach the force required in the specification, so that grouting is not needed, but whether slurry is poured to fill the gap can be determined according to the actual situation.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations may be made in the above embodiments by those skilled in the art without departing from the spirit and principles of the invention.

Claims

1. The recoverable winding type FRP anchor rod structure is characterized by comprising an expandable anchor head, a winding type FRP rod body (4) and an anchor; one end of the winding FRP rod body (4) is arranged in the expandable anchor head, and the other end of the winding FRP rod body is arranged in the anchor;

the expandable anchor head comprises an inner sleeve (1), an auxiliary support (2), a first spring (5), an outer sleeve (6) and a lock catch (7); the inner sleeve (1) is arranged in the outer sleeve (6), one end of the first spring (5) is connected to the bottom surface of the inner sleeve (1), and the other end of the first spring (5) is connected to the bottom of the outer sleeve (6);

the inner sleeve (1) is provided with a sleeve (10), the sleeve (10) is matched with the winding FRP rod body (4), the inner sleeve (1) is also connected with a plurality of auxiliary branches (2) through a rotating shaft, and the auxiliary branches (2) radiate to the periphery by taking the sleeve (10) as the center; the auxiliary support (2) is provided with a through hole (9);

the lock catch (7) is connected with the outer sleeve (6) through a pin shaft, and the middle section of the lock catch (7) is connected with the side wall of the outer sleeve (6) through a second spring (8); the lock catches (7) are arranged in one-to-one correspondence with the auxiliary support (2), the tail ends of the lock catches (7) are in contact with the auxiliary support (2) in the inserting process of the winding type FRP rod body (4), and the tail ends of the lock catches (7) are inserted into the through holes (9) in the recycling process of the winding type FRP rod body (4).

2. The recoverable wound FRP anchor rod structure according to claim 1, wherein a rubber block (3) is further arranged on the inner sleeve (1), and the rubber block (3) is arranged between the auxiliary support (2) and the sleeve (10); in the inserting process of the winding type FRP rod body (4), the rubber block (3) is compressed by the auxiliary support (2).

3. The recoverable wound FRP anchor structure according to claim 2, wherein the contact rubber block (3) of the auxiliary support (2) forms an included angle of 30 degrees with the axis of the sleeve (10) in the state of no external force.

4. The recoverable wound FRP anchor structure according to claim 1, wherein the lock catch (7) is a rod-like structure, and a telescopic projection is provided at the end of the lock catch (7).

5. The recoverable wound FRP anchor rod structure of claim 1, wherein the anchor comprises a fixed table (11), an expanded tenon block (12) and a counter-force table (14); the expansion tenon block (12) is matched with the winding FRP rod body (4), one end of the expansion tenon block (12) is arranged in the counter-force table (14), and the other end of the expansion tenon block is fixed through the fixing table (11); the restraint block (13) is arranged in the counter-force table (14) and is arranged outside the expansion tenon block (12).

6. The recoverable winding type FRP anchor rod structure according to claim 5, wherein the inner side walls of the sleeve (10) and the expanded tenon block (12) are provided with internal threads, and the internal threads are matched with external threads on the winding type FRP anchor rod body (4).

7. The recoverable wound FRP anchor rod structure according to claim 1, wherein the outer side wall of the wound FRP rod body (4) is coated with lubricating oil or sleeved with a plastic film.

8. A recoverable wound FRP anchor structure according to claim 1, characterized in that the first springs (5) are four and evenly distributed.

9. A recyclable wound FRP anchor structure in accordance with claim 2, characterized in that the rubber block (3) is of oval configuration.

10. A method of constructing a recyclable wound FRP anchor according to any one of claims 1 to 9, comprising the steps of:

construction of the expandable anchor head: the winding type FRP rod body (4) is combined with the expandable anchor head, the expandable anchor head is inserted into a drill hole, the auxiliary support (2) is extruded by soil body to reduce the rotation angle, after the expandable anchor head reaches a preset position, the winding type FRP rod body (4) is pulled, the auxiliary support (4) is expanded by the thrust of the rubber block (3) and gradually bites into the soil body, and anchoring force is provided for the winding type FRP rod body (4);

recovering the winding FRP rod body (4): the external anchorage device is removed, then the winding type FRP rod body (4) is continuously inserted into the drilled hole, the through hole (9) reaches the position of the lock catch (7) in the process that the inner sleeve (1) compresses the first spring (5), the lock catch (7) is inserted into the through hole (9) under the action of the restoring force of the second spring (8), the auxiliary support (2) is limited to expand outwards, and accordingly the winding type FRP rod body (4) is pulled out of the drilled hole, and recovery is achieved.