JPH01146013A - Fixed end structure of embedded member - Google Patents

Abstract

PURPOSE:To exactly anchor a built-in member by a method in which a tension force produced between the anchorage end and the buried portion is transmitted through fibers arranged in a tapered form. CONSTITUTION:A tension force produced between a bar part 3 buried in the ground 2 and the anchorage end 4 set on the surface 2a of the ground 2 and coupled with a fixer is transmitted through a continuous fiber 9 consisting of light-weight, high-strength glass fibers. The fiber 9 is pressed into the head cover 23 by the action of tapered wedge. The end of the built-in member can thus be exactly anchor.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a structure of an anchoring end of an embedded member that is embedded in a support made of the ground or a concrete structure to prevent collapse of the support. It is related to.

[Traditional branch needles]

Embedded members include, for example, earth anchors that stabilize the ground by being buried in the slope of the ground that makes up the retaining wall; There are rock bolts that fix walls and prevent deformation of walls, and tension materials for prestressed concrete.

Among these embedded materials, those indicated by the code type in Fig. 6 have fiber-reinforced plastic (hereinafter referred to as “F”)
rtP") is a conventional example of a rock bolt whose constituent body is a rock bolt. The reference numeral 2 represents the ground (supporting body) that forms the inner wall surface of a tunnel or the slope of a retaining wall, for example.
It is.

The rock bolt 1 consists of a bar-shaped buried part 3 buried in the ground 2, and a fixing device or the like formed on one end of the buried part 3 and installed on the surface 2a of the ground 2 or the surface 2a. and a fixing end portion 4. The buried portion 3 is inserted into a hole 5 that is drilled almost perpendicularly from the surface 2a of the ground 2, and the gap formed between the buried portion 3 and the hole 5 is filled with cement mortar, foaming urethane resin, etc. , or filled with a filler 6 such as an adhesive. This buried part 3 is made up of a core material 7 forming its axial center and a covering material 8 forming the periphery of the core material 7.
Made of MF RP. The core material 7 is made of synthetic resin, wood, water-resistant synthetic paper, or the like. The rock bolt l (embedded member) whose buried portion 3 is constructed using FRP in this way has no fear of corrosion due to salt, etc., and also has 1? Since I'lP has a smaller elastic modulus than steel material, the rate of stress relaxation etc. occurring due to long-term use can be made extremely small.

The fixing end portion 4 formed at one end of the buried portion 3 is configured by an end portion of the core material 7 protruding longer than the covering material 8.

Here, what is indicated by the reference numeral 40 in the figure is a fixing device composed of a bearing plate 41 made of steel and a pipe 42 made of FRP. Also, a pipe 42 is formed at the position where the pipe 42 of the bell-shaped puffer plate 41 comes into contact.
An insertion hole 41a is formed which has approximately the same diameter as the inner diameter of the through hole 41a. That is, in order to fix this lock bolt 1 (embedded member) to the ground 2 (support body) with this fixing end 4, the embedded part 3 is inserted into the perforation 5 of the ground 2, and the filler material 6 is inserted therein. After injecting and hardening, the fixing end 4, that is, the end of the core material 7 protruding from the ground surface 2a,
such that the fixing end portion 4 is inserted through the fixing tool 40;
and the bearing plate 41 is provided so as to come into contact with the surface 2a (after that, a wedge 4 is provided on the end surface of the fixing end portion 4).
3, the tip of the fixing end 4 is pushed out and hooked onto the pipe 42.

[Problems that the invention attempts to solve]

By the way, the anchoring end portion 4 having the above-mentioned structure, when a certain kind of displacement is about to occur in the ground 2, transfers the displacement force to the surface 2a.
The bearing plate 41 of the fixing device 40 that is in contact with the By doing so, the effect of suppressing the displacement of the ground 2 is produced.

However, in the fixing end portion 4, the lock bolt 1 is fixed only by the frictional force between the tip of the core member 7 and the wedge 43 driven therein.
This fixation resistance is extremely weak against the displacement force of the ground 2, and the ground I! If a large displacement force occurs on li2, the wedge 43
It often happened that the wedge 43 came off or the part of the core material 7 into which the wedge 43 was driven was damaged, resulting in the wedge being completely ineffective. By the way,
In experiments conducted by the present applicant, it has been found that the yield strength of the fixing end portion 4 having the above structure is 1/3 to 1/8 of the yield strength of the buried portion 3.

Further, FIG. 7 shows a lock bolt 11 that was experimented with by Motoyama, Ganto, and others, with the fixing end portion 4 having a structure different from that described above. The buried portion 3 of this rock bolt 11 is constructed using FrtP like the buried portion 3 of the rock bolt 1 described above, but in this rock bolt 11 (1 core material 7 is made of plastic, The formed covering material 8 is made of FRP.The fixing end portion 4 has one end of the core material 7 and the covering material 8 formed longer than the bearing plate 41 so as to protrude. It is constructed by carving a screw 12 into the portion and further screwing a nut 13 there. This structure also makes it possible to fix the rock bolt. However, the yield strength of the fixing end portion 4 of this structure is 115 to 1/1 of the yield strength of the buried portion 3.
It was extremely small at 0.

In other words, in the conventional embedded member, the strength of the embedded member as a whole is controlled by the strength of the fixing end portion 4, and even if the embedded portion 3 is constructed with high strength, There was a risk that the entire function would be lost due to damage to the fixing end. The present invention has been made in view of the above circumstances, and is intended to provide a fixing end structure that can exhibit high yield strength in an embedded member in which the embedded portion 3 is constructed using FILP.

[Means for solving problems]

□The present invention includes a rod-shaped buried portion buried in a support made of the ground or a concrete structure, and a fixing end formed at one end of the buried portion and anchored to the surface of the support. and at least the buried portion includes a plurality of 5at along the longitudinal direction at intervals in the circumferential direction.
11, the structure of the fixing end portion of the embedded member made of fiber-reinforced plastic is formed to have a larger diameter than the embedded portion via a step with the embedded portion,
In addition, one end of the nJi fiber is continuously extended inside the fiber, and the extended fiber is arranged in such a manner that the diameter of the extended fiber gradually expands toward the tip and then gradually decreases in diameter through a folded portion. It is characterized by:

[Effect]

This fixing end is formed to have a larger diameter than the buried portion as a whole, thereby forming a stepped portion with the buried portion, and the stepped portion is formed on the support surface or a bearing plate (bearing pressure I& ) etc.

When a relative force, especially a tensile force, is applied between the buried part and its stepped part, the fibers in the tapered part receive that force due to the action of the taper, and further transfer the tensile force to the above. It can be transmitted smoothly to the buried part. In other words, the tensile force of the buried portion is smoothly transmitted to the anchoring end by the fibers extending into the anchoring end, and the tensile force is distributed in the diameter-expanding tapered shape of the Ia fibers. The taper action (wedge action) of the part that has been removed reliably transfers and fixes the material to the stepped part. Furthermore, the fibers arranged in a tapered shape can prevent the core portion of the fixing QIS, which is formed inside the tapered fibers, from coming out outward.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention, in which an embedded member according to the present invention is applied to a rock bolt.

The reference numeral 20 in the figure is a rock bolt to which the present invention is applied. 2, or a fixing end portion 4 that is latched to a fixing device or the like installed on the surface 2a. The buried portion 3 is inserted into a hole 5 that is drilled almost perpendicularly from the surface 2a of the ground 2, and the gap formed between the buried portion 3 and the hole 5 is filled with cement mortar, foaming urethane resin, etc. , or filled with a filler 6 such as an adhesive. The buried part 3 consists of a core material 7 that forms its axial center and a covering material 8 that forms the periphery of the core material 7, and has a structure as shown in FIG. 2 (cross-sectional view). . The core material 7 is made of synthetic resin, wood, water-resistant synthetic paper, or the like. The covering material 8 formed around this core material 7 consists of continuous fibers 9.9.・
Resin material reinforced by 10. In other words, it is made of FRP. A plurality of continuous fibers 9 are embedded in the wood material 10 along the longitudinal direction of the core material 7 and at intervals in the circumferential direction of the core material 7.

As the continuous fiber 9, a fiber made by combining a plurality of lightweight and high-strength thin fibers such as glass fibers and carbon fibers and bundling a plurality of them is preferably used.
If necessary, other fibers such as synthetic resin fibers, ceramic fibers, metal fibers, etc. may be used, or these fibers may be used in appropriate combinations. Resin material 1
0, a resin that has good attachment properties to the continuous fibers 119 and has sufficient strength properties itself, such as vinyl ester resin, is preferably used, but depending on the material of the continuous fibers 8 used, Other resin materials may also be used.

Other resins in this case include unsaturated polyester resins, epoxy resins, phenol resins, and the like.

Further, in the embodiment, the surface of the resin material 10 constituting the buried portion 3 is finished in an uneven shape by forming a large number of protrusions 10a. This is to increase the adhesion force between the buried portion 3 and the filling material 6, and in addition to the illustrated protrusion 10a, a continuous protrusion may be formed in a spiral shape, such as a screw thread, for example. Alternatively, a large number of ring-shaped protrusions may be provided, or, conversely, grooves may be formed.

In short, the surface of the resin material 10 may be made rough.

The fixing end portion 4 is formed to have a larger diameter as a whole than the buried portion 3 via a step portion 21 between the fixing end portion 4 and the buried portion 3 .

In this case, a tapered core 22 is formed at the axial center of the fixing end portion 4, with one end surface abutting the end of the core material 7 of the buried portion 3. In this case, the tapered core 22 is solid FRP.
The part of the proximal end that abuts the core material 7 is formed to have approximately the same diameter as the core material 7, but the diameter gradually increases from the proximal end toward the distal end. , and is formed into a tapered shape that reduces in diameter again. The covering material 8 constituting the buried portion 3 continues to this tapered core 22 and extends along the tapered surface 22Jl. In other words, this allows the continuous fiber 1! , 9
is arranged at its fixing end in the same form as the tapered surface 2.2a of the tapered core 22, that is, in a tapered shape that gradually increases in diameter toward the tip, then forms a folded portion 9a, and then decreases in diameter again. There is. Furthermore, a head covering 23 is provided on the outside of the tapered core 22 through the above-mentioned covering material.
is formed. In this case, the head covering 23 is formed by winding glass fiber impregnated with vinyl ester resin. The end surface of this head covering 23 is the step part 21
It is forming.

Next, the function of the fixing end portion 4 having the above structure will be explained.

As shown in FIG. 1, the lock bolt 2o having the fixing end 4 has the fixing end 4 protruding from the surface 2a of the ground 2, and a bearing plate 41 is placed between the fixing end 4 of the bracket and the surface 2a. It is used in the state through. At this time, the step portion 21 comes into contact with the surface of the bearing plate 41. Now, suppose that a displacement force is generated in the direction indicated by arrow Y in the figure due to some influence on the ground 2. The displacement force is transmitted to the step part 21 of the head part [23] via the bearing plate 4M. As a result, the head cover 123 receives a force directed outward (leftward in the figure), but this head cover 23
cannot move due to the action of the tapered surface 22a of the tapered core 22. At this time, the force that causes the head covering 23 to move outward is transmitted to the covering material 8 formed along the tapered surface 22m of the tapered core 22, particularly to the continuous fibers 9 disposed inside the covering material 8. . Since the continuous fibers 9 at the fixed end portion 4 are continuous from the buried portion 3, the force is converted into a tensile force in the longitudinal direction of the continuous fibers 9 and is smoothly transmitted to the buried portion 3. That is, the displacement force of the ground 2 is effectively transmitted to the buried portion 3 via the continuous fibers 9, and is effectively suppressed. Since the stress generated in the fixing end 4 is effectively transmitted to the buried part 3, the buried part 3 has sufficient strength, but only the fixing end 4 receives a small displacement force. This causes early damage to the lock bolt (
There is no possibility that the entire function of the implanted member will be lost. Incidentally, according to the authors of the present applicant, it has been found that the yield strength of the fixing end portion 4 of the lock bolt 20 according to this embodiment can exhibit a value equivalent to the yield strength of the buried portion 3. . Further, according to the fixing end portion 4 having the above structure, the continuous fibers 9 form the folded portion 9a and have a tapered shape with a tapered end.
2 is prevented from being pulled out outwardly. To explain the core material 7 for reference here, only the tensile force acting on the buried portion 3 along its longitudinal direction, and this tensile force mainly applies to the covering material 8.
Continuous fibers arranged along the longitudinal direction of 9.9. ...
However, since the holder has a support, the core material 7 only has to play the role of an inner mold used for molding the rod-shaped member, and the core material 7 itself is not required to have strength.

In the illustrated example, the continuous fibers 9 disposed inside are arranged in a tapered shape similar to the tapered core 22 by placing the covering material 8 along the chi and par cores 22. The resin material 10 constituting the material 8 may be formed up to a portion corresponding to the stepped portion 21 of the head covering 23, and only the continuous fibers t119 may be extended into the fixing end portion 4.

In other words, in this case, the extended continuous fibers 9 are directly connected to the tapered core 22 and the head covering 23 without intervening the resin material 10.
The composition is sandwiched between.

FIG. 3 shows a second embodiment of the present invention, in which the same components as those of the first embodiment are given the same reference numerals to simplify the explanation thereof. In the second embodiment, the core material 7 constituting the buried portion 3 has a hollow cylindrical shape. Therefore, the tapered core 22 configuring the fixing end portion 4 is as follows:
It is formed in the shape of a plug to close the open end of the core material 7. The other configurations are the same as those of the first embodiment. The function of the fixing end portion 4 according to the second embodiment is similar to that of the first embodiment.

4 and 5 show a third embodiment of the present invention, and the same components as those of the first embodiment are given the same reference numerals to simplify the explanation thereof. The third embodiment shows an example in which the embedded member according to the present invention is applied to a tendon material for prestressed concrete. In these figures, reference numeral 25 indicates a concrete member (supporting body) into which prestress is introduced, reference numeral 2G indicates a sheath pipe disposed within the concrete member 25, and reference numeral 30 indicates a prestressed concrete member inserted into the sheath pipe 2G. Tensile material (
-Reinforced parts).

The tendon material 30 is composed of a buried portion 3 buried within the sheath tube 26 and a fixing end portion 4 formed at one end of the buried portion 3. The structure of the buried part 3 and the structure of the fixing end part 4 are as follows.
It may be considered to be similar to the first embodiment or the second embodiment described above. The head wave [23] of the fixing end portion 4 is formed in close contact with the resin material 10 constituting the covering material 8 of the buried portion 3, as in the above embodiment; It may be constructed integrally with the material 10. Also, as a side note, the tension material 30 according to this embodiment. In this case, the protrusion 10a formed in the buried portion 3 has a spiral shape. The end of the buried portion 3 opposite to the fixed end 4 is fixed to a concrete member 25, as shown in FIG. Reference numeral 40 denotes a fixing device, which includes a bearing plate 41 to which a nut 44 is welded. A perforated bolt 45 is screwed onto the nut 44 and has a perforated shaft center so that the tension member 30 can be inserted through the shaft center, and a threaded portion 45a of the perforated bolt 45 is screwed into the perforated bolt 45. It is composed of a lock nut 46 that has been tightened.

That is, the tension material 30 is applied with a predetermined tension force to the entire tension material 30 by pulling its fixing end 4 using a jack or the like (not shown), and then the perforated bolt 45 of the fixing device 40 is moved to tighten the tension material 30. The end surface is brought into contact with the stepped portion 21 of the fixing end portion 4 U', and then the lock nut 46 is tightened into the nut 4.
By tightening on the 4th side, prestress is introduced. Note that, thereafter, a filling material 6 such as mortar is filled between the buried portion 3 of the tendon material 30 and the sheath tube 2G.

Even in the case of the tension material 30 (embedded member) as described above, if the fixed end portion 4 has the above structure, the continuous fibers 9 disposed along the long direction of the embedded portion 3 will form the taper. Since it extends along the core 22, the tension force introduced into the fixing end portion 4 by the tension force introduction means is smoothly transmitted to the buried portion 3. In addition, after the tension force is fixed, the tensile stress h of the buried portion 3 (transmitted to the continuous fibers 9- in the fixed end portion 4, and the continuous fibers 9 are pressed against the head VT cover 23 by the wedge action of the taper to ensure It is firmly established.

In addition, in all the above three embodiments, the taper core 22 is
However, if the core material 7 of the buried portion 3 is also constructed from FRP, the tapered core 22 may be constructed integrally with the core material 7. In addition, in the above three embodiments, the structures shown in the first and second embodiments are applied to rock bolts,
Furthermore, the structure shown in the third embodiment was explained as being applied to a tension material for prestressed concrete.
The fixed end structure is not limited to those of these examples depending on the type of embedded member, but for example, the structure shown in the first example may be applied to the tendon material for prestressed concrete, Alternatively, it is of course possible to apply the present invention to other embedded members such as earth anchors.

〔Effect of the invention〕

As explained above, according to the fixing end structure according to the present invention, the relative force, especially the tensile force, generated between the main fixing end and the buried part is extended from the buried part to the fixing end. The tensile force can be effectively transmitted between the fibers arranged in a tapered manner, and the tensile force can be reliably fixed by the wedge action of a portion of the tapered fibers arranged in a tapered shape. Therefore, the fixed end portion of the embedded member whose embedded portion is made of fiber-reinforced plastic can exhibit extremely high yield strength, and the overall functionality of the embedded member can be improved.

[Brief explanation of the drawing]

Figures 1 and 2 show the first embodiment of the present invention. Figure 1 is a side sectional view showing the vicinity of the fixing end of the lock bolt, which is the part of the embedded member, and Figure 2 is the first embodiment of the present invention. FIG. 3 is a cross-sectional view of the buried portion of the rock bolt shown in the figure. FIG. 3 shows a second embodiment of the present invention, and is a partial sectional view showing the vicinity of the fixing end of the lock bolt, and FIGS.
The figure shows a third embodiment of the present invention, FIG. 4 is a side sectional view showing the vicinity of the fixed end of a tendon for prestressed concrete, which is the part of the embedded member, and FIG. 5 is a side sectional view of the same tendon. FIG. 6 and 7 show a conventional example according to the present invention, and both are side sectional views showing the vicinity of the fixing end of the lock bolt. 2... Ground (support), 2a...
Surface portion, 3...Buried portion, 4...Fixed end portion, 9...Continuous fiber 1 (fiber t11), 9a
・・・・・・Folding part, ! l...Rock bolt (embedded member), 20...Rock bolt (embedded member), 21...Step part, 30
...Tension material (embedded member).

Claims (1)

[Claims] It consists of a rod-shaped buried part buried in a support made of the ground or a concrete structure, etc., and a fixed end part formed at one end of the buried part and locked to the surface part of the support, The structure of the fixing end portion of the embedded member is such that at least the embedded portion is made of fiber reinforced plastic reinforced with a plurality of fibers extending in the longitudinal direction at intervals in the circumferential direction, the embedded portion The fiber is formed to have a larger diameter than the buried part through a stepped part, and one end of the fiber is extended inside the buried part, and the extended fiber gradually expands in diameter toward the tip. 1. A fixed end structure of an embedded member, characterized in that the structure is arranged in such a manner that the diameter gradually decreases through a folded portion.