JP2948738B2 - Spacer for tension member, permanent anchor body, and method of forming the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent anchor used for preventing a landslide on a rock surface or a slope, or for stabilizing a concrete structure such as a dam or a pier, and a tension member used for these. It is related to a spacer of a material.

[0002]

2. Description of the Related Art An anchor of this type is disclosed in, for example,
No. 62-211423, a corrugated sheath is placed over the tension steel material to enable double rust prevention in combination with the surrounding grout, and the free length of the tension steel material shown in JP-B 1-37532 It is known to use a heat-shrinkable tube for joining a corrugated tube and a straight tube during the fixing length. It is also known to use a resin-coated full-thread steel bar as a tension steel material.There is also a method of injecting a paste-like resin as shown in JP-B-3-38368 to form a water-stop portion. Proposed.

[0003]

2. Description of the Related Art In the method of double rust prevention described above, it takes time and effort to attach a corrugated sheath and inject grout, and the diameter of a fixing length portion becomes large.
There is a problem that the diameter of the anchor hole to be formed must be large.

In a method using a heat-shrinkable tube,
If tension acts, the tube may crack, and the method of injecting the paste-like resin requires time and care for construction. .

[0005] A method using a fully threaded steel bar as a tendon material is as follows.
Although the construction is easy and it is not necessary to increase the diameter of the anchor hole, the coating thickness of the resin is suppressed to about 200 μm in order to obtain the adhesive strength to concrete. Because it is so thin, care must be taken not to damage the film during construction, and there is a risk of rusting due to the damage.

The present inventors have previously proposed Japanese Patent Application No. 5-151482 in order to solve the problems described above. According to this proposal, the tension steel is preliminarily subjected to corrosion protection, the tip of the tension steel is protected by a cap, a water stop section is provided between the free length section and the fixing length section, and the fixing length is further increased. A spacer is provided in the part to improve the corrosion resistance.

[0007] Although the above-mentioned proposal has achieved the intended purpose, the outer periphery of a PC steel stranded wire which has been subjected to anticorrosion treatment such as, for example, an epoxy resin coating on the free length portion, and the polyethylene having the stranded wire inserted therethrough. The clearance between the inner wall of the protective tube such as a sheath is small and may come into contact with each other.
This contact increases the resistance in tensioning the strand.

[0008] This increase is not a problem when the length of the free length portion is about 20 m or less, or when the anticorrosion is only made of epoxy resin coating, but the length of the free length portion is 50 m due to dam construction or the like.
Or such as using a stranded wire having improved fixability by fixing silica sand or the like to the resin surface,
The increase is about 10% or more. To cope with this large tension loss, it is necessary to increase the capacity per anchor body or to increase the number of anchors, so that there is a problem that the construction period is extended and the cost is increased.

[0009]

The present invention solves this problem by improving the method of inserting and assembling the components by devising each of the constituent members constituting the anchor body. The features are described.

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

That is, an insertion hole is formed of hard polyethylene or the like, which penetrates the center of the spherical body, and a spacer is formed using this as an insertion hole of a grout injection hose. The support of the tendon is provided by providing a number of tendon members on the outer surface of the spherical body whose groove bottom is parallel to the insertion hole, and using the number of the tendon. Since it is spherical, there is little resistance in pushing the tendon material into the narrow hole, and there is little hindrance such as kinking or tilting. Therefore, the structure of this spacer has a feature that it is widely used as a spacer for a tendon, not limited to a permanent anchor.

(Free Spacer Spacer) The second feature of the present invention is that the above spacer is used not for the fixed length portion of the permanent anchor but for the free length portion and in the free length portion and the fixed length portion. That is. In each case, one or two
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 used as a spherical spacer as described above, but has an insertion hole at the center and a split groove at the outer periphery. The outer peripheral portion can be used as a curved surface or a rhombus shape so that the insertion is not hindered by other shapes such as a desk shape.

(Water Stop Part) 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 fixing length portion and the free length portion of the tension member. Is to form a wedge-shaped water stop portion. It is preferable that a cut is provided in the water stop portion so that a tension member is fitted from the outside.

(Tip Cap) A fifth feature of the present invention is that
The fixing caps on the fixing side of the plurality of tendon members are individually covered with tip caps for rust prevention and protection.

(Spacer for Fixing Length) A sixth feature of the present invention is that the spherical spacer is used as a spacer to be attached to the fixing portion of the tendon.

(Tensioning material) Another feature of the present invention is that all the tensile steel materials used as the tensioning material are previously subjected to a corrosion protection treatment. As the anti-corrosion treatment, use a PC steel stranded wire coated with an epoxy resin to a coating thickness of about 600 μm, and then bury sand such as silica sand in the outer layer at a depth that does not reach the innermost layer of the coating. Is preferred.

(Creation Method) A permanent anchor using the above-described spacer is formed as follows. A spacer is attached to each of the anchoring length portion and the free length portion of the tendon material, and a wedge-shaped water blocking portion is formed at the boundary between the two portions by an elastic composition, and is connected to a sheath covering 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 prepared anchor body member is inserted into the hole, grout is injected and solidified, and then the tension member is tensioned and fixed.

[0019]

FIG. 1 is a schematic view showing an entire structure of an anchor body in an embodiment, and is a longitudinal sectional view of the anchor body. FIG.
FIG. 3 is a longitudinal sectional view for explaining details of the anchor head of FIG. 1 and FIG. 4A and 4B show FIG.
It is sectional drawing of AA and BB of FIG.

In the drawing, reference numeral 1 denotes a tension member inserted into a hole 3 provided in a wall surface 2. In the embodiment, a plurality of epoxy strands are used, and a plurality of epoxy strands are used at the tip thereof, each of which is made of plastic or resin-coated metal. Rust prevention is performed by attaching a tip cap 4 for rust prevention such as made of steel. The reason why they were separately applied is that it is impossible to cope with a change in the number of the collective caps due to design deformation and the like, and the rust prevention effect is also obtained.
Of course, if necessary, a collective cap can be used. Reference numeral 5 denotes a wedge-shaped water-stop portion made of 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 above-mentioned epoxy strand 1 is made of an anticorrosion tensile steel material having an outer diameter of 15.2 mm, which is formed by twisting seven steel wires and coated with an epoxy resin.
Four are inserted in the inside. Silica sand is fixed to the outer surface of the coating.

The water stopping portion 5 has a cylindrical shape so that the grout injection hose 6 can be inserted into the center, and has an epoxy strand 1 on its outer periphery.
The anticorrosion tape is provided with a notch so as to be fitted therein and connected integrally with the end of the polyethylene sheath 7 on the free length side.
It is wound and fixed at 22. The anticorrosion tape 22 is preferably formed by first winding a petrolatum tape by 50% wrapping over the epoxy strand 1, the water stopping portion 5, and the polyethylene sheath 7 as shown in FIG.

Numeral 8 is a plastic spacer loaded on the support of the fixing length of the epoxy strand 1, and FIG.
As shown in the figure, a hard polyethylene spherical body 23 has four insertion grooves 24 extending through the center of the grout injection hose 6 and a groove bottom 26 provided on the outer peripheral surface thereof in parallel with the insertion hole 24. twenty five
It is provided with. Each epoxy strand 1 is supported by the split groove 25. 27 is a vinyl tape which holds the spacer 8. Although one spacer is used in the drawing, a plurality of spacers can be used if necessary.

The spacer 8 is formed as described in Japanese Patent Application No. 5-151482.
The most preferred form of the spacer in the number is an image. Another feature of the present invention in which a spacer is used for the fixing length portion is that a spacer of this shape is also provided for the free length portion. In the figure, two spacers installed at the free length are shown, but if necessary, one spacer or three or more spacers may be used. By providing in the free length part, for example, even if the free length is as long as about 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 member 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 the free length portion. Therefore, in the present invention, the spacer to be provided in the free length portion is the same as the above-mentioned spherical shape. The shape is not limited to this, and may include a shape formed in an oval shape or the like so as not to be caught on the wall or the like at the time of insertion, to form a curved surface or a rhombus shape on the insertion tip side (fixing end side).

The above-described structure of the spherical spacer makes it easy to fit required members into the insertion holes 24 and the split grooves 25, respectively.
It has a feature that it can be used not only for permanent anchors but also as a spacer for other tendons as needed, because it has low resistance during movement and good maintenance of the fitting member.

The end of the polyethylene sheath 7 opposite to the water-stop portion 5 is connected to a joint sheath 9 which is inserted into and adheres to the center hole of the anchor plate 10 at the anchor head. 11 is a bearing pipe used for the connection, 12 is an O-ring, 13 is a water-stop packing, and 14 is a circular plate in contact with the outside of the anchor plate 10 which also assists connection and constitutes a tension fixing. is there. With this configuration, the sealing effect is enhanced, and the tension of the next epoxy strand 1 is sufficiently maintained.

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

Reference numeral 20 denotes a rust-preventive cap that covers a portion of the tension fixing device constituted by the circular plate 14, one end of the epoxy strand 1, a ring nut 16, and the like. An O-ring 19 is provided at the joint with the anchor plate 10. Attached and the space inside the cap is made of the same rust-preventive material as grease as in the free length sheath
21 is filled.

In the anchor body of the present invention, a drilled hole 3 is first opened in a required ground and a construction wall surface, and after a water stopping process is performed on the hole 3,
The above-mentioned equipment is mounted in the hole 3, and the prepared tensile steel material is inserted from the front end of the fixing length, and the primary grout is injected into the fixing length from the grout injection port as conventionally performed. , Forming a fixing length portion, tensioning a tensile steel material, fixing a fixing device in an anchor plate portion, secondary injection of grout to the outer periphery of a sheath, and the like, or a known or new process.

In the anchor body of the present invention constructed and configured as described above, the anchoring length exposed at the water stopping portion is protected by the corrosion protection of the tensile steel material and the tip cap and grout, and the free length is the same as that of the tensile steel material. Corrosion protection and protection with rust preventives, sheath and outer grout. Therefore, a heavy-duty anticorrosion 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 related art. In addition,
When a tendon made of a material having a high anticorrosion property, such as a fibrous tendon, is used, it is, of course, unnecessary to further perform anticorrosion treatment.

[0031]

As described above, the spherical spacer of the present invention has a smooth mounting and movement of the tendon material and the like, and in the anchor of the present invention, the anchoring length is two times by the anticorrosion tensile steel material and the surrounding grout. Since it has a heavy anti-corrosion structure, there is no need to attach a sheath to this part or inject anti-corrosion material as in the past, so the outer diameter of the fixing length can be made thinner and the drilling diameter can be small. .

The water-blocking portion is formed by the elastic composition, and the spherical or curved surface or rhombic spacers are used for the free length and the fixing length, respectively. And the leakage of the rust preventive material in the sheath to the outer periphery or the intrusion of corrosive water from the outer periphery into the sheath can be reliably prevented.

As described above, the drilling hole diameter is small, the workability in forming is good, and there is little possibility of scratching the steel material.
Since the position is maintained and the water stoppage is sufficient, the construction cost is reduced,
The intended anchor effect is improved.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view for explaining an entire structure of an anchor body according to an embodiment of the present invention.

FIG. 2 is a similar longitudinal sectional view for explaining the anchor head of FIG. 1 in detail.

FIG. 3 is a similar longitudinal sectional view for explaining in detail a water stop portion of FIG. 1;

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

[Explanation of symbols]

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

Continued on 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 8-14-14 Ginza, Chuo-ku, Tokyo Date (56) References JP-A-6-212629 (JP, A) JP-A-6-108463 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02D 5 / 80

Claims (8)

(57) [Claims] 1. A spherical body, wherein 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 are formed on the outer surface of the spherical body. Tensioner spacer. 2. An anchor head for fixing a free length side end of a tendon material to a construction wall, a free long portion in which the outer periphery of the tendon material is covered with a sheath in a drilled hole following the head, and covering with a sheath. An anchor having a fixing length portion on the side of the fixing end without a fixing portion, the free length portion has a grout injection hose insertion hole in the center portion, and a plurality of split grooves for supporting the tendon material on the outer periphery portion.
The fixing end side has a curved surface or
A permanent anchor body comprising one or more ridge- shaped spacers . 3. The free length spacer as claimed in claim 1,
3. The permanent anchor according to claim 2, wherein the spacer according to claim 2 is used. 4. An anchor head for fixing a free length side end of a tendon to a construction wall, a free long portion in which a periphery of the tendon is covered with a sheath in a drilled hole following the head, and covering with a sheath 2. An anchor comprising a fixing end portion having no fixing end and a fixing end portion, wherein at least one spacer according to claim 1 is attached as a spacer for supporting said tendon material by a split groove in the fixing length portion. Anchor body. 5. An anchor head for fixing a free-length side end of a tendon to a construction wall, a free-length portion in which the outer periphery of the tendon is covered with a sheath in a drilled hole following the head, and covering with a sheath. 4. A fixing end portion having no fixing end, and a water stopping portion formed in a wedge shape by an elastic composition at a boundary between the free length portion and the fixing length portion. Or a permanent anchor according to 4. 6. The permanent anchor body according to claim 5, wherein the water blocking portion has an insertion hole for a grout injection hose inside, and a plurality of cutouts for supporting a tendon material outside. 7. An anchor head for fixing the free length side ends of a plurality of anticorrosion tendons to a construction wall surface, and a free length portion in which an outer periphery of the anticorrosion tendon is covered with a sheath in a drilled hole following the head. And an anchor having a fixing end portion on the fixing end side that is not covered by a sheath, wherein a plurality of anticorrosion tip caps are separately applied to the fixing ends of the plurality of anticorrosion tendons. 7. The permanent anchor according to claim 2, 3, 4, 5 or 6. 8. Fixing of a plurality of tension members subjected to anticorrosion treatment
Attach multiple tip caps separately to the tip
Free length part, anchoring length part of the tendon member having an injection pipe
A spacer is attached to each of the
A wedge-shaped water stop made of an elastic composition
Attach one end of the sheath covering the part so that it is fixed and sealed.
And the above-mentioned tendon material after each of the above steps is cut from the fixing end.
Insert the opposite end of the sheath into the free length end
To the joint sheath leading to the anchor head
Connecting and sealing the permanent anchor.
-How to create a body.