JP2590930Y2 - Anchor body for ground anchor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anchor for a ground anchor used for works such as stabilization of a slope and foundation of a bridge in a civil engineering business.

[0002]

2. Description of the Related Art A ground anchor method (earth anchor method) is used as a method for preventing collapse and fall of earth retaining walls, retaining walls, and the like, and for obtaining a bridge foundation. Conventionally, in such a ground anchor method, a steel rod or a bundle of a plurality of stranded PC steel wires as disclosed in Japanese Patent Publication No. 58-47516 has been used as an anchor body. In this anchor body, PC
The stranded steel wire is rust-proofed with a synthetic resin coating and oil, bundled together with two grouting hoses, and further covered with a sheet to form a hole. The grout is filled inside and outside with two grout injection hoses, and after the grout in the fixing portion hardens to reach a predetermined strength, a tensioning operation is performed. The head is fixed by a fixing device.

[0003] However, the conventional anchor body uses a steel stranded wire, and in order to secure corrosion resistance, its surroundings are rust-proofed with a synthetic resin coating and grease, and further covered with a corrugated sheath to grout. Double rust prevention treatment of injection is applied. For this reason, special equipment is required, it takes a lot of time and effort, and the outer diameter of the anchor body increases,
There is a problem that the diameter of the drill hole must be large, which increases the construction cost. In addition, the stranded steel wire generally used for the ground anchor weighs 700 to 9000 g per meter, and the total weight is 1 in the case of a 20 m class multi-type ground anchor.
As a result, the workability is poor, such as transportability and insertion into a hole. As a countermeasure, Japanese Patent Application Laid-Open No. Hei 5-33336 proposes an anchor body using a cable made of carbon fiber or aramid fiber. However, this prior art has a problem that the fixing efficiency with the grout is poor because the fixing length region is only the end of each cable fixed with a spacer.

The present invention has been devised in order to solve the above-mentioned problems, and its purpose is to eliminate the need for rust prevention work and to improve workability such as transportation and insertion into a hole. An object of the present invention is to provide an anchor body for a ground anchor which is excellent, has excellent adhesion to concrete, can realize a good anchoring effect, and has a small hole diameter, and can reduce the construction cost.

[0005]

According to the present invention, to achieve the above object, grout is injected into a drilled hole, an anchor body comprising a plurality of cables bundled is inserted into the drilled hole, and the tip portion is inserted. Anchor body used in a method of anchoring the base end after being arranged and fixed in the grout, and each cable of the anchor body is made of a composite material of high-strength high-elastic fiber and thermosetting resin. In the structure, a free long range is formed by covering each cable with a sheath tube and filling a gap between the cable and the outer periphery of the cable with a flowable substance. Provided between the plurality of composite filaments constituting the cable is a cage-like node portion in which a ring-shaped spacer is interposed so as to fit the composite filament located at the center of the cross section, and , Each cage section is provided with the phase shifted between each cable It is characterized. In addition, the feature of the present invention is that, in addition to the above-described configuration, each cable has a cage-shaped node portion having a different phase from each other in a portion near the tension applying side terminal,
The fixing section 8 for introducing a tension by inserting the end of each cable including this into the socket and filling and curing the thermosetting resin is configured.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a state in which an anchor body 1 according to the present invention is buried in a hole A formed in the ground. The anchor body 1 converges a plurality of (for example, 3 to 10) cables 2 made of a composite material of a high-strength, high-elasticity fiber and a thermosetting resin, and separates the cables 2 by spacing spacers 9 and 9 ′. There is an appropriate space between them. 2 to 4 show cables 2
In order to avoid complicated rust prevention treatment, it is better to use a material that does not rust.However, since the cable is a tension material, it is not enough just to have good corrosion resistance. It must have good strength and long-term stability of tension (creep resistance) and also have properties such as good adhesion to concrete.
Therefore, the present invention uses a composite material of high-strength, high-elasticity fiber and a thermosetting resin as the cable 2.

The cable 2 is formed by impregnating a high-strength, high-elasticity fiber with a thermosetting resin and curing the thermosetting resin to form a continuous body having a predetermined cross-sectional shape and an outer diameter. It has a strand structure in which a plurality of filaments 20 are twisted as strands. The composite striatum 20 is
A specified amount of thermosetting resin such as epoxy resin, unsaturated polyester resin or polyurethane resin is impregnated into a yarn made up of a number of ultra-fine long fibers with high strength and high elasticity such as carbon fiber, polyaramid fiber and silicon carbide fiber. After forming and removing excess resin with a shaping die, apply a powder desiccant such as talc to the surface of the yarn, dry the surface, and wind or braid a synthetic fiber such as polyester or nylon around the outer periphery. It is provided with a coating. The cable 2 is made by passing a plurality of the composite filaments 20 through a twisting machine, twisting them at a required pitch and twist direction, and heat-treating the impregnated thermosetting resin in this state. ing. In this example, seven composite filaments 20 are used,
Although it has a seven-strand structure, it is not limited to this, and may be any of five-strand, six-strand, eight-strand, and nine-strand.

In the longitudinal direction, the cable 2 has a fixing length region L to be connected to the grout B and a free long region L 'to be unbonded to the grout B and to introduce tension. As shown in FIGS. 2 and 3, the free length region L 'is covered with a sheath 3 made of synthetic resin or the like so as to have a predetermined clearance with the outer periphery of the cable 2, and a liquid or paste is applied to the clearance. The sheath is filled with a fluid material 4 having a shape such as a grease shape, and both ends of the sheath 3 are closed with a sealing material 5 such as a resin. The fixing length range L is determined not only by each cable 2 being exposed, but also by one of the cables 2 as shown in FIGS.
A cage-like node portion 6 that protrudes in the radial direction at more than one place is formed. The cage-shaped section 6 is formed by loosening the twist of the cable 2 and interposing the inflating spacer 7 between the composite filaments 20 constituting the cable 2. Voids 70 are formed between the bodies 20.

The spacer 7 has a ring shape (including a short tube) made of a synthetic resin or the like. However, as shown in FIG. Good.
This has the advantage that it can be interposed from the side of the cable. The cross-sectional shape of the spacer 7 is arbitrary such as a circular shape or a polygonal shape, and may have positioning concave portions 71 corresponding to the number of the composite filaments 20 as shown in FIG. The method of making the cage-shaped section 6 is to loosen the twist of the terminal of the cable 2 over a required length, and insert the spacer 7 from the terminal to a predetermined position so as to externally fit the composite filament 20 located at the center. What is necessary is just to take the method of returning a twist in that state. Spacer 7
In the case where a member having a cutout portion 72 for opening and closing as shown in FIG. 5A is used, it can be inserted and inserted from the side of the portion where the cage-shaped node is to be formed. The basket-shaped section 6
When the cable is provided at the same position in a plurality of cables 2, the diameter of the anchor body becomes large, and the inflow and adhesion of the grout are prevented, so that the cage-shaped nodes 6 do not overlap between adjacent cables. It is desirable to displace them appropriately as in 1.

[0010] A fixing portion 8 for introducing a tension is provided on the tension end side of each cable 2. This fixing unit 8
Is arbitrary, but in this embodiment, a screw 82
The end of the cable is inserted into a steel socket 80 engraved with a thermosetting resin 81 between the inner surface of the socket and the outer periphery of the cable.
A resin-filled socket type that is filled and cured.
In this case, in order to improve the adhesiveness with the resin, the end of the cable is provided with a cage-like node similar to the fixing long area. Instead of this, a buffer layer is formed of a soft alloy around the cable end,
A method of fastening with wedges may be used. The above-described fixing is performed for each cable. However, in order to apply a tension at a time, more preferably, one fixing unit 8 is provided as a whole in a state where the plurality of cables 2 are converged. This is because, as shown in FIG. 6, each of the cables 2, 2 is formed with the above-described cage-shaped node portions 6, 6 at different phases, and
May be inserted into the socket 80 and filled with the thermosetting resin 81 to be hardened. In some cases, the fixing length side terminal of the cable 2 or the fixing length side terminal of the anchor body 1 is surrounded by a socket made of a synthetic resin or the like, and a thermosetting resin is injected and cured between the inner surface of the socket and the cable. May be formed.

In the anchor body 1 for a ground anchor according to the present invention, a plurality of, for example, six cables 2 shown in FIG. 2 are prepared, and the cables 2 are arranged so that the cage-shaped nodes 6 do not overlap each other. The spacers 9 are attached to the free long region L 'at predetermined intervals, and the spacers 9' are also attached to the fixing long region L at predetermined intervals to achieve a convergence state. The spacing spacers 9 and 9 ′ are simply formed with holes in the plate body, but the spacing spacer 9 ′ in the fixing long region L is, for example, an arc groove 90 in the center as shown in FIG. Divided body 9 having a circular groove 91 on the outer periphery
a, 9a are used, and after the gap is determined by the split bodies 9a, 9a, the two split bodies 9a, 9a may be bonded or a flange provided in advance may be connected by bolts or the like. The spacing spacer 9 may be prevented from moving in the longitudinal direction by friction with the sheath. The spacing spacer 9 'is prevented from moving by the cage-shaped nodes 6, 6, but if necessary, through holes are provided in advance at the outer edges, bolts or rods are passed through them, and nuts are tightened. The spacing spacers 9 ', 9' may be connected to each other by gluing or the like. As described above, the spacer 9 'for maintaining the interval at the end of the fixing long region L surrounds a socket made of a synthetic resin or the like, and is formed by injecting and hardening a thermosetting resin on the inner surface of the socket to form a terminal joint. Be stopped. The processing of the fixing unit 8 may be performed on each of the cables 2 and 2 in this state, or may be performed in advance. At the time of construction, the grout B is injected into the bottom of the drilling A, and the ground anchor 1
Is inserted into the hole A, and the fixing length region L is disposed in the grout B. Then, after the grout B is hardened, each cable 2 is tensioned by a jack (not shown) until a predetermined tension is reached, and after the tension, the fixing unit 8 may be stopped on the support plate 11 by nuts or wedges 10.

The tension member of the anchor body 1 for a ground anchor is a composite filament 2 made of a high-strength, high-elasticity fiber and a thermosetting resin.
It is composed of a plurality of cables 2 each having a strand structure in which a plurality of strands are twisted with 0 as a strand. Since the tendon itself has excellent corrosion resistance, a complicated double rust prevention treatment is performed. Can be completely omitted, and since the rust prevention treatment is not required, the diameter can be reduced, and the excavation hole can be reduced in diameter. In addition, since it is lightweight, it is easy to carry, and workability such as insertion into a hole can be dramatically improved. In the free length region L 'of each cable 2, the sheath 3 is surrounded, and the clearance between the inner surface and the outer surface of the cable is filled with a fluid substance 4 such as water, so that tension is applied. The fluidity 4 is opposed to the cable 2 even when it is subjected to an external pressure by the grout B, so that the cable 2 and the sheath 3 do not abut each other. Can be introduced. On the other hand, in the fixing length range L, the cable 2
In addition to the fact that the material is well compatible with grout and has high adhesion strength to concrete, each cable 2 is provided with a ring-shaped spacer 7 at the center of the cross section of the composite filament 2.
0 has a cage-like node 6 bulged in the outer diameter direction so as to be fitted to the outside, so that the area of attachment to the grout B is large, and the composite filament 20 forming the cable 2 is formed. , 20 penetrates into the cable through the gap between
The grout B is securely adhered also to the outer periphery of the composite striated body 20 at the central portion, so that the knots are integrally formed with the striated bodies 20 from inside and outside. Since this node exerts pull-out resistance, the fixing strength is high, and thus the length of the fixing length region can be shortened. In addition, the cage-shaped node 6 is not formed by plastically deforming the composite linear body 20, but the ring-shaped spacer 7 is formed.
Because of this, no decrease in tensile strength occurs, and no knot forming member such as a pressure grip is used, so that the strength of the high-strength and high-elastic fibers that are weak against shearing does not decrease.

Next, a specific example of the anchor for a ground anchor according to the present invention will be described. A carbon fiber yarn having a diameter of 0.007 mm and a number of filaments of 12,000 is impregnated with 35% by weight of an epoxy resin, and a plurality of prepregs are twisted, and a synthetic fiber is wound around the outer periphery to form a strand. Further, this element wire is twisted in a configuration of one in the center and six in the side, and finally heat-treated to cure the epoxy resin, and the outer diameter is 12.5 mmφ.
Thus, a cable having a seven-stranded strand structure was obtained.
The characteristics of this cable were determined by using a steel wire (7 strands, diameter 12.4
mmφ), as shown in Table 1 below, which shows that the material is lightweight, has high strength, has excellent creep resistance, and has excellent adhesion to concrete.

[0014]

[Table 1]

The cable 2 has an inner diameter of 20 mm
Was filled with water, and the end of the polyethylene tube was sealed with resin. Further, for the fixing length range, the twist is varied, and the length is 10 mm, the outer diameter is 10 mmφ,
After attaching a spacer made of synthetic resin having an inner diameter of 7.5 mm at three places, the twist was returned to the original state to form a cage-like node. The spacer mounting positions were appropriately shifted so that the cage-shaped nodes did not overlap between a plurality of cables. Then, six such cables were arranged and converged while arranging spacers for keeping the length in the longitudinal direction to obtain an anchor body for a ground anchor. The ground anchor was inserted after grouting was injected into the bottom of the drilled hole, and the grout was hardened and tensioned and fixed. The characteristics at this time are shown in Table 2 in comparison with a comparative example in which a cage-shaped node is not formed and a conventional example using six steel wires from PC. In this experiment, the length of the fixing length region was set to be equal.

[0016]

[Table 2]

As is apparent from Table 2, the present invention is light in weight and small in diameter and has a fixing length as short as about 1 / 3.6 of that of the conventional product. It can be seen that it can be set to 1.4.

[0018]

According to the present invention described above, since each cable of the anchor body is composed of a composite material of high-strength high-elastic fiber and thermosetting resin, rust prevention treatment is not required and weight is reduced. The workability such as transportation and insertion into a drill hole can be remarkably improved due to its light weight, and the free long range L 'is covered with the sheath tube 3 for each cable and the cable 2
Is filled with the flowable substance 4 so that the degree of freedom of the cable is good and the tension can be reliably applied. In addition, for each of the cables 2 in the fixing length region L, the composite filament 20 located at the center of the cross-section is separated from the composite filament 20 forming the cable 2 by the ring-shaped spacer 7. Since the cage-shaped section 6 is provided so as to be fitted, it covers the weak point of the high-strength and high-elasticity fiber which is susceptible to shearing, and prevents the tension from being reduced due to plastic deformation while adhering to the grout. The grout can be sufficiently penetrated into the composite filament 20 at the center of the cable 2, whereby the fixing efficiency is high and the fixing length can be shortened. In addition, since the cage-shaped nodes 6 with the ring-shaped spacers 7 interposed therebetween are provided with phases shifted from each other between the cables 2, 2, the outer diameter of the anchor body can be reduced, and The flow of grout into or adhesion to the grout is not hindered, and the drilling diameter can be reduced despite the high fixing efficiency, thereby providing an excellent effect that the construction cost can be reduced. According to claim 2, each of the cables 2, 2 has a cage-like node portion 6, 6 having a mutually different phase at a portion near the tension applying side terminal, and the end of each of the cables 2, 2 including this. Part is inserted into the socket 80 and the thermosetting resin 8
Since the fixing portion 8 for introducing tension by filling and hardening the resin 1 is formed, the resin enters the cage-like nodes 6, 6 to form a node, and therefore, a high tension is ensured. An excellent effect of easily obtaining a head fixing portion that can withstand the above is obtained. The whole cable at once

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of an anchor body for a ground anchor according to the present invention.

FIG. 2 is a partially cutaway side view showing an example of the cable according to the present invention.

FIG. 3 is a sectional view of a free long range.

FIG. 4 is a sectional view of a fixing long region.

FIG. 5 is a sectional view showing an embodiment of an inflating spacer used in the present invention.

FIG. 6 is a partial cross-sectional view illustrating another example of the fixing unit according to the present invention.

FIG. 7 is a cross-sectional view showing an example of the spacing spacer according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anchor body for ground anchors 2 Cable 3 Sheath tube 4 Fluid material 6 Basket-shaped node part A Drilling hole B Grout L Fixing length area L 'Free length area

Continuation of the front page (56) References JP-A-5-33336 (JP, A) JP-A-4-281999 (JP, A) JP-A-51-141002 (JP, U) JP-A-4-33736 (JP) , U) Tokiko Hei 3-38368 (JP, B2) "Basic Construction October Issue, 1991 Vol. 19, No. 10", page 43, October 15, 1991, published by Research Institute of Civil Engineering (58) ) Surveyed field (Int.Cl. ⁶ , DB name) E02D 5/80

Claims (3)

(57) [Scope of request for utility model registration] A grout is injected into a drilling hole, an anchor body having a plurality of cables bundled is inserted into the drilling hole, and its tip is placed and fixed in the grouting, and then tensioned. An anchor body used for a method of anchoring a base end, wherein each cable of the anchor body is composed of a composite material of high-strength high-elastic fiber and thermosetting resin, and a sheath tube is provided for each cable. The free long range L 'is formed by covering the gap 3 with the flowable substance 4 in the gap between the cable 2 and the outer periphery of the cable 2. The cable 2 is formed in each cable 2 of the fixing long range L. A cage-like node portion 6 in which a ring-shaped spacer 7 is interposed between the plurality of composite filaments 20 so as to fit the composite filament 20 positioned at the center of the cross section is provided. The cage section 6 is provided with a phase shift between the cables 2 and 2. Anchor body for land anchor. 2. Grout is injected into the drilling hole, an anchor body having a plurality of cables bundled is inserted into the drilling hole, and its tip is placed and fixed in the grouting, and then tensioned. An anchor body used for a method of anchoring a base end, wherein each cable of the anchor body is composed of a composite material of high-strength high-elastic fiber and thermosetting resin, and a sheath tube is provided for each cable. The free long range L 'is formed by covering the gap 3 with the flowable substance 4 in the gap between the cable 2 and the outer periphery of the cable 2. The cable 2 is formed in each cable 2 of the fixing long range L. A cage-like node portion 6 in which a ring-shaped spacer 7 is interposed between the plurality of composite filaments 20 so as to fit the composite filament 20 positioned at the center of the cross section is provided. The cage section 6 is provided with a phase shift between the cables 2 and 2. 2 and 2 have cage-shaped nodes 6 and 6 having different phases from each other in a portion near the tension applying side terminal,
The ground is characterized in that a fixing section 8 for introducing a tension by inserting the end of each of the cables 2 and 2 including this into the socket 80 and filling and curing the thermosetting resin 81 is configured. Anchor body. 3. An anchor for a ground anchor according to claim 1, wherein the high-strength, high-elasticity fibers are carbon fibers.