JPH0885946A - Spacer for tensioning material, and permanent anchor and its manufacture - Google Patents

Abstract

PURPOSE: To make a permanent anchor which can work with a small boring diameter even though the length of a free length part is increased and also which presents good easiness in working, is economical, and heavily protected against corrosion. CONSTITUTION: An anchor is composed of a head for fixing the free length side end part of a tightening member 1 to a wall surface to be constructed 2, a free length part where the periphery of the tightening member 1 is enclosed with a sheath 7 in the bored hole continued from the head, and a fixed length part on the fixed side free from enclosure with such sheath 7, wherein a water stop part 5 in wedge form made from an elastic composition is installed at the boundary of the free length part with the fixed length part. A spherical spacer 8 is fitted on each of the free length part and fixed length part. Tip caps 14 are mounted on the fixed ends of anti-corrosive tensile steel members. These operations are performed individually or simultaneously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent anchor body used for preventing landslides on rocks and slopes, and for stabilizing concrete structures such as dams and bridge piers, and tensions used for these. It is related to the spacer of the material.

[0002]

2. Description of the Related Art Anchors of this type include, for example, JP-A
In 62-211423, a tension steel material is covered with a corrugated sheath to enable double rust prevention in combination with the surrounding grout, and in Japanese Patent Publication No. 1-37532, the free length of the tension steel material It is known to use heat shrink tubing to join the corrugated tubing and straight tubing to the fixing length. It is also known to use a resin-coated full-thread steel rod as a tensile steel material, and a method of injecting a paste-like resin as shown in Japanese Patent Publication No. 3-38368 to form a water-stop portion is also known. Proposed.

[0003]

[Problems of the prior art] In the double rust prevention method described above, it is necessary to attach a corrugated sheath and to inject grout and the like, and the diameter of the fixing length portion becomes large.
There is a problem that the diameter of the hole for forming the anchor for forming this must be large.

In the method using the heat shrink tube,
Tension force may cause cracks in the tube, and the method of injecting the paste-like resin requires time and effort for construction, etc. .

The method of using a fully threaded steel rod as the tension material is as follows.
Construction is easy and there is no need to increase the diameter of the drilled hole in the anchor, but the coating thickness of the resin is suppressed to around 200 μm in order to obtain adhesion strength with concrete. Since it is thin like this, care must be taken not to scratch the film during construction, and there is a concern that rust may occur due to scratches.

The present inventors have previously proposed Japanese Patent Application No. 5-151482 in order to solve the problem of the strength. In this proposal, the tension steel material is subjected to anti-corrosion treatment in advance, and the tip of the tension steel material is protected by a cap during the construction, and a water stop is provided between the free length portion and the fixing length portion. A spacer is provided inside the part to improve the corrosion resistance.

Although the above-mentioned proposal was able to achieve the intended purpose, the outer circumference of the PC steel stranded wire which was subjected to anticorrosion treatment such as epoxy resin coating in the free length portion, and the polyethylene inserted through the stranded wire The clearance with the inner wall of the protective tube such as the sheath is small and may contact each other.
This contact increases the resistance in tensioning the strand.

This increase does not cause much trouble when the length of the free length is about 20 m or less or when the anticorrosion is only the epoxy resin coating, but the length of the free length is 50 m due to dam construction.
In the case of using a stranded wire having a fixing property improved by fixing silica sand or the like on the resin surface,
The increase is about 10% or more. To deal with this great loss of tension, it is necessary to increase the capacity per anchor body or increase the number of anchors, which causes a problem that the construction period increases and the cost increases.

[0009]

In order to solve this problem, the present invention has been devised in each of the constituent members constituting the anchor body, and improved in the method of inserting and assembling the same. The features will be described.

(Spherical Spacer) In the above-mentioned Japanese Patent Application No. 5-151482, the inventors of the present invention have used an outer periphery as a spacer for supporting a tension member of a fixing long portion so that a corner portion toward the fixing end side does not occur. Proposed a curved or rhombus shape,
The present invention seeks to provide a spherical spacer as its most effective structure.

That is, a through hole is formed through the center of the spherical body by using hard polyethylene or the like, and a spacer is formed by using this as a through hole for the grout injection hose. The tension member is supported by providing a number of tension members on the outer surface of the spherical body whose groove bottom is parallel to the insertion hole, and by using the division grooves. Since it is spherical, there is little resistance when pushing the tensioning material into the narrow drilling hole, and there are few obstacles such as kinking and tilting. Therefore, the structure of this spacer has a characteristic that it is widely used as a spacer for not only permanent anchors but also tendons.

(Free Spacer Spacer) The second feature of the present invention is that the above spacer is used not for the fixed length part of the permanent anchor but for the free length part and between the free length part and the fixed length part. That is. In either case, 1 or 2
More than one can be used.

A third feature of the present invention is that the spacer used for the free length portion is not necessarily separated from the spherical spacer as described above, and the insertion hole is provided at the center and the split groove is provided at the outer periphery. That is, the outer peripheral portion can be used as a curved surface or a rhombus so that other shapes such as a desk shape do not hinder the insertion.

(Water stop portion) A fourth feature of the present invention is that a stretchable material such as an elastic composition such as rubber or synthetic resin is provided at the boundary between the fixed length portion and the free length portion of the tension member. To form a wedge-shaped water stop. It is preferable to make a cut in the water blocking portion so that the tension member is fitted from the outside.

(Tip Cap) The fifth feature of the present invention is that
A tip cap for rust prevention and protection is attached to each of the plurality of tension members on the fixing-side tip thereof.

(Fixing Long Spacer) The sixth feature of the present invention is to use the spherical spacer as a spacer attached to the fixing portion of the tension member.

(Tensile Material) Another feature of the present invention is that all the tensile steel materials used as the tensile materials are previously subjected to anticorrosion treatment. For anticorrosion treatment, use an epoxy resin coated on a PC stranded wire with a coating thickness of about 600 μm, and embedding sand such as silica sand in the outer layer to a depth that does not reach the innermost layer of the coating. It is preferable.

(Formation Method) The permanent anchor body using the spacer as described above is formed as follows. Spacers are attached respectively to the fixed length portion and the free length portion of the tension member, and a wedge-shaped water stop portion is formed by an elastic composition at a boundary portion between the both portions to connect with a sheath that covers the free length portion. The opposite end of the sheath connects to a joint sheath leading to the anchor head, completing the free length sheath. The anchor member thus prepared is inserted into the drilled hole, and after the grout is injected and solidified, the tension member is tensioned and fixed.

[0019]

EXAMPLE FIG. 1 is a schematic view showing the overall structure of an anchor body in an embodiment, and is a longitudinal sectional view of the anchor body. Figure 2
1 is a vertical cross-sectional view for explaining the details of the anchor head portion of FIG. 1 and FIG. 4A and 4B are shown in FIG.
It is sectional drawing of AA and BB of FIG.

In the figure, reference numeral 1 is a tension member inserted in a hole 3 formed in a wall surface 2. In the embodiment, a plurality of epoxy strands are used, and a plurality of epoxy strands are individually provided at the tip of each of them, a plastic or resin coated metal. The front end cap 4 for rust prevention such as manufacturing is attached to measure rust prevention. The separate caps are attached because it is impossible to deal with the case where the number of caps changes due to design deformation or the like, and the rust preventive effect is also taken.
Of course, if necessary, a one-piece cap can also be used. Reference numeral 5 denotes a water blocking portion formed in a wedge shape from a stretchable elastic composition such as silicone rubber, nitrile rubber, neoprene, or urethane resin, and is provided at the boundary between the free length and the fixing length of the epoxy strand 1. The epoxy strand 1 is a corrosion-resistant tensile steel material having an outer shape of 15.2 mm, which is obtained by twisting seven steel strands together and coating an epoxy resin.
Four of them are inserted inside. Moreover, silica sand is fixed to the outer surface of the coating.

The water stop portion 5 is cylindrical so that the grout injection hose 6 can be inserted through the center thereof, and the epoxy strand 1 is formed on the outer periphery thereof.
A tape that is provided with a notch so that the tape can be fitted and is integrally connected to the end of the polyethylene sheath 7 on the free length side.
It is wound and fixed at 22. As shown in FIG. 3, the anticorrosion tape 22 may be formed by first wrapping a petrolatum tape by 50% wrapping over the epoxy strand 1, the water blocking portion 5, and the polyethylene sheath 7, and further winding a self-bonding tape around the outer periphery.

Numeral 8 is a plastic spacer loaded to support the fixed length of the epoxy strand 1, which is shown in FIG. 4B.
As shown in FIG. 4, a spherical body 23 made of hard polyethylene is provided with a through hole 24 for the grout injecting hose 6 penetrating the center of the spherical body 23, and a groove bottom 26 provided on the outer peripheral surface of the spherical body 23. twenty five
It is provided with. The split groove 25 supports each epoxy strand 1. Reference numeral 27 is a vinyl tape that holds the spacer 8. Although one spacer is used in the figure, a plurality of spacers can be used if necessary.

The spacer 8 is formed according to the above-mentioned Japanese Patent Application No. 5-151482.
The most preferable form of the spacer in No. 1 is an image. Further, in the present invention in which the spacer is used for the fixing length portion, it is another feature that the spacer of this shape is installed also in the free length portion. In the figure, two spacers installed in the free length portion are shown, but if necessary, one spacer or three or more spacers may be used. By installing it in the free length part, for example, even in the case of a large free length of around 40 m,
By providing the spacers at intervals of 5 m, it is possible to prevent an increase in tension loss due to the tension material coming into contact with the sheath.

Further, in the above-mentioned Japanese Patent Application No. 5-151482, there is no mention of providing a spacer in this free length portion. Therefore, in the present invention, the spacer installed in the free length portion is the above spherical one. However, the shape is not limited to that which does not catch on the wall of the drilled hole 3 at the time of insertion, the insertion tip side (fixing end side) has a curved surface or a rhombus shape, and includes an egg-shaped shape.

In addition, in the structure of the spherical spacer described above, it is easy to fit the required members into the insertion hole 24 and the split groove 25, respectively.
It has a feature that it can be used not only as a permanent anchor but also as a spacer for other tension members, if necessary, because it has a low resistance during movement and can maintain the fitting member well.

An end of the polyethylene sheath 7 on the side opposite to the water blocking portion 5 side is connected to a joint sheath 9 which is inserted into and closely attached to a central hole of an anchor plate 10 of an anchor head. Reference numeral 11 is a bearing pipe used for the connection, 12 is the same O-ring, 13 is the same water-tight packing, and 14 is a circular plate in contact with the outside of the anchor plate 10 that constitutes the tension anchorage while also helping the connection. is there. With this configuration, the sealing effect is enhanced, and the tension of the next epoxy strand 1 is sufficiently retained.

Numeral 15 is an anchor disk, which is circumscribed to the circular plate 14 via a ring nut 16 screwed onto the outer periphery thereof,
The epoxy strand 1 is pulled and held in the wedge hole via the wedge 17. Reference numeral 18 is a bush provided so as not to damage the epoxy strand 1.

Reference numeral 20 is a rust preventive cap covering a portion of the tension fixing device composed of the circular plate 14, one end of the epoxy strand 1, the ring nut 16 and the like, and an O-ring 19 is provided at the joint with the anchor plate 10. When installed, the space inside the cap is the same as in the free-length sheath, such as grease
21 is filled.

In the anchor body of the present invention, first, the drilled holes 3 are formed in the required ground and construction wall surface, and after water-stop treatment is applied to the drilled holes 3,
The above-mentioned equipment is attached into the drilled hole 3, the prepared tensile steel material is inserted from the end of the fixing length, and the primary grout is injected into the fixing length from the grout injection port as is conventionally done. It is formed through well-known or new processes such as forming a fixing long portion by means of, tensioning a tensile steel material, fixing a fixing member at an anchor plate portion, and secondary injection of grout to the outer circumference of the sheath.

In the anchor body of the present invention constructed and constructed as described above, the anchor length lengthened at the water stop portion is protected by the corrosion of the tensile steel material and the tip cap and the grout, and the free length is the same as that of the tensile steel material. It is anticorrosive and protected by a rust preventive material, a sheath and an outer grout. Therefore, a heavy-corrosion-proof structure can be obtained without attaching a sheath to the fixing length or injecting grout between the sheath and the tensile steel material as in the conventional case. In addition,
When using a tension material made of a highly anticorrosive material such as a fibrous tension material, of course, it is not necessary to further perform anticorrosion treatment.

[0031]

As described above, the spherical spacer of the present invention allows smooth attachment and movement of a tension member or the like. In the anchor body of the present invention, the fixing length depends on the anticorrosion tensile steel material and the surrounding grout. Since it has a heavy anticorrosion structure, it is not necessary to attach a sheath or inject a anticorrosion material to this part as in the past, so that the outer diameter of the fixing long portion can be made thin and the hole diameter can be small. .

By forming a water stop with an elastic composition and using spherical, curved, or rhomboid spacers for the free length and the fixed length, it is easy to mount and insert, and to the center of the drilled hole of anticorrosion tensile steel. Is also stably held, and leakage of the rust preventive material in the sheath to the outer periphery or intrusion of corrosive water from the outer periphery into the sheath can be reliably prevented.

As described above, the diameter of the drilled hole is small, the workability in construction is good, and the risk of scratches on the steel material is small,
Since the position is maintained and the water is stopped, the construction cost is reduced.
The desired anchor effect is improved.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional view for explaining the overall structure of an anchor body in an example of the present invention.

FIG. 2 is a similar vertical cross-sectional view for explaining the anchor head portion of FIG. 1 in detail.

FIG. 3 is a similar vertical cross-sectional view for explaining the water shut off part of FIG. 1 in detail.

4A is a sectional view taken along the line AA of FIG. 1, and FIG. 4B is a sectional view taken along the line BB of FIG.

[Explanation of symbols]

 1 Epoxy strand 2 Wall surface 3 Drilling hole 4 Tip cap 5 Water stop portion 6 Grout injection hose 7 Polyethylene sheath 8 Spacer 9 Joint sheath 10 Anchor plate 11 Bearing pipe 12, 19 O ring 13 Water stop packing 14 Circular plate 15 Anchor disc 16 Ring nut 17 Wedge 18 Bush 20 Anti-rust cap 21 Anti-rust material 22 Anti-corrosion tape 23 Spherical body 24 Insertion hole in spherical body 25 Split groove in spherical body 26 Groove bottom of split groove 27 Vinyl tape

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Etsuji Ishibashi 1-3-12 Moto-Akasaka, Minato-ku, Tokyo Sumitomo Electric Industries, Ltd. Tokyo Head Office (72) Inventor Hiroshi Yamada 14-14, Ginza, Chuo-ku, Tokyo No. 14 Nitoku Construction Co., Ltd.

Claims (9)

[Claims] 1. A spherical body is formed with one insertion hole penetrating the center of the spherical body and a plurality of split grooves having a groove bottom parallel to the insertion hole formed on the outer surface of the spherical body. Spacer for tension material. 2. An anchor head for fixing a free-length side end portion of a tension member to a construction wall surface, a free-length portion in which the outer periphery of the tension member is covered with a sheath in a hole drilled following the head, and a sheath covering In an anchor having a fixing length portion on the fixing end side without a spacer having a through hole for a grout injection hose in the center portion and a plurality of split grooves for supporting the tension member in the outer peripheral portion in the free length portion. A permanent anchor body comprising one or more. 3. The spacer of the free length portion as claimed in claim 1.
The permanent anchor body according to claim 2, wherein the spacer according to claim 1 is used. 4. An anchor head for fixing a free length side end of a tension member to a construction wall surface, a free length part in which the outer circumference of the tension member is covered with a sheath in a hole drilled following the head, and a sheath cover. An anchor having a fixing length portion on the side of the fixing end, wherein one or more spacers according to claim 1 are attached as spacers for supporting the tension member in the fixing length portion by split grooves. Anchor body. 5. An anchor head for fixing a free-length side end portion of a tension member to a construction wall surface, a free length portion in which the outer periphery of the tension member is covered with a sheath in a hole drilled following the head, and a sheath covering 4. A fixing long portion on the side of a fixing end having no water, and a water blocking portion formed in a wedge shape by an elastic composition at a boundary between the free length portion and the fixing long portion. Alternatively, the permanent anchor body according to item 4. 6. The permanent anchor body according to claim 5, wherein the water stop portion has an insertion hole for the grout injection hose therein and a plurality of cutouts for supporting the tension member on the outside. 7. An anchor head for fixing the free-length side ends of a plurality of anticorrosion tension members to a construction wall surface, and a free length portion in which the outer periphery of the anticorrosion tension members is covered with a sheath in a hole following the head. And an anchor having a fixing length portion on the fixing end side that is not covered by a sheath, each of the fixing ends of a plurality of anticorrosion tension members is covered with a rust preventive tip cap. The permanent anchor body according to claim 2, 3, 4, 5 or 6. 8. An anchor head for fixing an end portion of the anticorrosion tension material on a free length side to a construction wall surface, a free length portion in which a perimeter of the anticorrosion tension material is covered with a sheath in a drilled hole following the head portion, and a sheath. In an anchor that has a fixing length part on the fixing end side that is not covered by the above, in each of the free length part and the fixing length part, a spacer with a curved or diamond-shaped outer periphery is formed so that spherical or corners facing the fixing end side do not occur. The permanent anchor body according to claim 5, 6 or 7, wherein the permanent anchor body is attached. 9. A free-length portion and a fixing long portion of the tension member, each of which is provided with a grout injection pipe, in which a plurality of end caps are attached to the fixing-side ends of a plurality of anti-corrosion tension members. A spacer is attached to each of them, and each step of attaching a wedge-shaped water stop portion made of an elastic composition at the boundary between the fixed length and the free length so as to fix and seal one end of the sheath covering the free length portion, Inserting the tensioning material after the step into the drilled hole from the fixing side end, and connecting and sealing the opposite end of the sheath to the joint sheath connected to the anchor head fixing the free length side end. A method of creating a permanent anchor body characterized by.