JPH06146277A - Permanent anchor - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a permanent anchor structure capable of reducing the hole diameter, excellent in workability, and capable of heavy corrosion protection. [Structure] An anchor head for fixing the end of the deformed PC steel rod 1 to the construction wall surface, a free length portion for covering the outer periphery of the deformed PC steel rod with the sheath 2 in the drilled hole A, and no sheath covering It is a permanent anchor structure having a fixing long portion and a water blocking portion 7 at the boundary between them, and the deformed PC steel rod 1 is coated with a synthetic resin. With the synthetic resin coating, it is not necessary to provide a sheath in the fixing length portion as in the conventional case and to inject grout between the sheath and the tensile steel material. Therefore, the fixing long portion can be formed thin, and the drilling diameter can be small.

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 landslides such as slopes and landslides.

[0002]

2. Description of the Related Art As a conventionally known anchor,
For example, there is one shown in Japanese Utility Model Laid-Open No. 63-19038. This is one in which the free length part of the tensile steel material is covered with a straight pipe and the fixing length part is covered with a corrugated pipe, and the cement milk injected between the tensile steel material and the corrugated pipe and the corrugated pipe are doubled. It has an anticorrosion structure.

[0003]

Conventionally, as described above, this type of anchor has been capable of performing heavy corrosion protection by using a sheath together with surrounding grout as a double corrosion protection method. Therefore, in the fixing long portion, it is necessary to attach a sheath such as the corrugated tube or to inject a corrosion-proof material such as grout between the sheath and the tensile steel material, and the entire fixing long portion becomes large (thick). It was necessary to increase the anchor drilling diameter.

Further, the water stop portion at the boundary between the fixed length portion and the free length portion has conventionally been made by pouring resin or asphalt, which deteriorates workability during construction. Further, in order to dispose the tensile steel material in the central portion of the drilled hole, a steel lantern-shaped spacer made of steel has been externally fitted to the tensile steel material of the fixing length portion. However, since the conventional spacer has a lantern shape and a hollow interior, it cannot fully exhibit its function due to deformation and damage during the construction, which also causes a decrease in the adhesive strength of the fixing long portion.

The present invention has been made to solve the above problems, and an object thereof is to provide a double-corrosion permanent anchor which has good workability such as assembly and insertion, and low construction cost. To do.

[0006]

The features of the present invention include an anchor head for fixing an end of a tensile steel material to a construction wall surface, a free length portion for covering the outer circumference of the tensile steel material with a sheath in a drilling hole, and a sheath. A permanent anchor having a fixing long portion not covered by, and having a water stop at the boundary between the free long portion and the fixing long portion,
This is because a PC steel material obtained by coating the tensile steel material with a synthetic resin is used.

Here, as the synthetic resin, an epoxy resin is particularly preferable, and, for example, a polyethylene resin, a polyester resin, an acrylic resin, a urethane resin, a phenol resin, or the like can be used equally. Further, it is preferable to use a water blocking member that can be fitted to the PC steel material as the water blocking portion, and to block water between the sheath distal end portion. Further, the arrangement of the tensile steel material in the drilled hole is adjusted by fitting the spacer to the PC steel material of the fixing length portion. Furthermore, a nut may be fitted to protect the PC steel material tip of the fixing length portion. Then, it is preferable that the sheath covering the free length portion is connected to the head anchor plate through-hole through the joint sheath, and the water blocking packing is provided at least at two positions inside the joint sheath.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the overall structure of the embodiment. An anchor head for fixing an end of a tensile steel material to a construction wall surface, a free-length portion in which a tensile steel material outer periphery is covered with a sheath in a drilling hole, and a sheath It consists of an uncovered fixing part.
The constituent members of each part are as follows.

(Tensile steel material) The length of the tensile steel material extends over the entire area from the head portion to the fixing length portion, and the tension force from the head portion is transmitted to the anchor body. A deformed PC steel rod 1 formed and coated with epoxy resin was used. If a long tensile steel material is required, the coupler 4 is used to join the tensile steel materials in the middle.

(Sheath) The free length portion of such a tensile steel material is covered with, for example, a polyethylene sheath 2, and a rust preventive material 3 is injected between the sheath 2 and the deformed PC steel rod 1. .

(Spacer) On the other hand, a disk-shaped spacer 5 is screwed onto the deformed PC steel rod 1 of the fixing length portion. This is for arranging the deformed PC steel rod 1 substantially in the center of the drilled hole A, and is preferably made of rubber or plastic so that the epoxy resin coating of the deformed PC steel rod does not peel off.

(Nut) Further, a nut 6 is screwed onto the end of the deformed PC steel rod of the fixing length portion. This is to prevent damage to the tip portion, especially peeling of the epoxy resin coating, when the tensile steel material is inserted into the drilled hole A. The nut 6 and the spacer 5 serve as a resistance against the tension force when the anchor body is formed by the injection of the grout G, and also have a function of improving the adhesive force between the deformed PC steel rod and the grout G.

(Water Stopping Section) As described above, the water stopping section 7 is formed at the boundary between the free length section covered with the sheath and the fixing length section not covered with the sheath. This water stop portion is shown in an enlarged manner in FIG. In the figure, 7a is a water blocking member screwed into the deformed PC steel rod 1 and has a cylindrical shape with both ends tapered. This one end is inserted into the distal end portion of the sheath 2, and the inner peripheral surface of the sheath and the outer peripheral surface of the water blocking member are brought into close contact with each other, thereby reliably stopping water in the free length portion. Further, at the other end, an anticorrosion tape 7b is wound around the outer periphery of the end portion of the sheath 2 around the water blocking member 7a and the outer peripheral surface of the deformed PC steel rod 1 to ensure the water blocking reliability. Since this water blocking member 7a is also screwed into the deformed PC steel rod 1, it is preferably made of rubber or plastic from the viewpoint of epoxy resin coating protection.

(Anchor head) All the above-mentioned components are installed in the drilled hole, but the head for fixing one end of the deformed PC steel rod 1 to the construction wall surface is the anchor plate, the fixing nut, It consists of a circular plate, etc.
The space between the free length portion is sealed and a predetermined tension is applied. Hereinafter, description will be given based on FIG. 3 in which the vicinity of the head is enlarged.

(Anchor plate) Anchor plate 8
Is a disk-shaped member for supporting the entire anchor head, has a through hole 8a in the center, and a joint sheath 9 described below is inscribed and joined thereto.

(Joint sheath) Joint sheath 9
Is made of plastic, for example, and has a flange 9a at one end.
It has a cylindrical shape. Excluding this flange
Although it has a uniform outer diameter over the entire length, the inner diameter from the flange-side open end to the substantially central portion in the axial direction is larger than the inner diameter on the opposite side (the other end). That is, the inner peripheral surface of the sheath is thin on the flange side (thin portion 9
b), the opposite side is thick (thick portion 9c) is formed in a step shape. A packing groove 9d for mounting the water blocking packing 10 is formed on the inner peripheral surface on the other end side of the sheath.

(Pressure Bearing Pipe) This is also a cylindrical pipe used for joining with the joint sheath 9 to the free length portion and for stopping water. The outer diameter is approximately equal to the inner diameter of the thin portion of the joint sheath, and the inner diameter is substantially equal to the inner diameter of the thick portion of the joint sheath. Also, as described below, the thin part of the joint sheath
The O-ring is stored at the end of 9b, and the bearing pipe 11 is
When installed in 9b, it is formed to have a length slightly protruding from the flange-side opening end of the joint sheath.

The connection between the anchor plate and the sheath 2 is
First, the water-tight packing 10 is stored in the packing groove 9d of the joint sheath 9, and the O-ring is also attached to the end of the thin portion 9b.
12 is accommodated and this joint sheath 9 is inserted into the through hole 8a of the anchor plate 8. Next, insert the sheath opening of the free length into the joint sheath 9, and attach the flange 9a.
Are arranged so as to contact the peripheral edge of the through hole 8a. Then, the bearing pipe 11 is inserted between the inside of the thin portion of the joint sheath 9 and the sheath 2.

Before the deformed PC steel rod is tensioned, the bearing pipe 11 is connected to the flange 9a of the joint sheath as described above.
Since it protrudes further, there is at least a gap for this protrusion between the circular plate 13 and the anchor plate 8 described below. However, when tension is applied, the circular plate 13 and the anchor plate 8 come into close contact with each other due to the tension force, and the bearing pipe 11 is pushed toward the O-ring 12 side. for that reason,
The O-ring 12 is fixed, compressed and deformed between one end of the bearing pipe 11 and the end of the thin portion of the joint sheath to enhance the sealing effect. With the above configuration, a joint portion having water blocking packings at both ends of the joint sheath 9 is formed.

(Fixing Nut and Circular Plate) The circular plate 13 has a circular hole through which the deformed PC steel rod 1 passes, and is arranged on the anchor plate 8. The fixing nut 14
The tension force is maintained by fitting one end of the tensile steel material and pressing the circular plate 13 to fix the one end of the tensile steel material.

(Rust-proof cap) The rust-proof cap 15 is a cup-shaped member that covers a fixing tool composed of a circular plate 13, one end of a tensile steel material, a fixing nut 14 and the like. A ring 16 is attached and a space inside the cap is filled with a rust preventive material 17 to improve corrosion resistance.

(Construction Method) Construction is carried out by various conventionally used construction methods, but the following method is generally used. First, as shown in FIG.
Open and apply water stop treatment there. Next, the anchor body having the above configuration is inserted into the drilled hole. Then, the primary grout G is injected into the fixing long portion to form an anchor body, and the tensile steel material is tensioned. Finally, anchoring of the head and secondary grout injection to the outer circumference of the sheath are performed to complete the anchor construction.

As described above, by using the modified PC steel rod coated with the epoxy resin, the fixing length portion is protected by the epoxy resin coating and the outer peripheral grout, and the free length portion is covered with the epoxy resin coating, the rust preventive material, Protected by the sheath and its outer grout. Therefore, a heavy-duty anticorrosion structure can be obtained without attaching a sheath to the fixing length portion or injecting grout between the sheath and the tensile steel material as in the conventional case.

Further, since the deformed PC steel rod is used as the tensile steel material, the water stopping member of the water stopping portion, the spacer of the fixing length portion, and the nut of the tip portion can be screwed together, and these can be securely and easily carried out. Can be fixed to tensile steel. Therefore, the asphalt injection work is not required in the water shut-off portion as in the conventional case, and the workability is improved. Further, since the spacers and nuts can be firmly attached, it is possible to surely arrange the tensile steel material properly in the drilled hole and protect the tip end portion of the tensile steel material during construction.

Further, in joining the sheath of the free length portion and the head anchor plate, a waterproof packing is provided at the end portion of the joint sheath, and the O-ring in the central portion is supported by using a tension force. By compressing and deforming with a pipe, it is possible to easily and surely join and to stop the water.

[0026]

As described above, according to the anchor of the present invention, the following effects can be expected. By using a PC steel material coated with synthetic resin, a double anticorrosion structure can be created along with the surrounding grout in the fixing length part, so it is necessary to attach the sheath and inject the anticorrosion material as in the past. Not. Therefore, particularly, the fixing long portion can be formed thin, and the drilled hole diameter can be small.

By attaching a spacer and a nut that can be fitted to the PC steel material of the fixing length portion, the tensile steel material can be stably arranged in the substantially central portion of the drilling hole, and when the tensile steel material is inserted into the drilling hole, it is pulled. The tip of the steel material can be protected. Since these are firmly fixed to the tensile steel material, they do not fall off or get loose during the work. Then, when the grout is injected and the anchor body is formed, these spacers and nuts contribute to strengthening the adhesive force between the tensile steel material and the grout.

As a water blocking portion at the boundary between the free length portion and the fixing length portion, a water blocking member that can be fitted into the PC steel material and can be inserted into the sheath end portion is used.
Alternatively, it is possible to reliably prevent the intrusion of corrosive water into the sheath. Further, unlike the conventional case, it is not necessary to inject asphalt during the work of forming the water blocking portion, which is excellent in workability.

A joint sheath is used to connect the anchor head and the sheath, and water-proof packing is provided on the anchor head side and the anchor body side of the joint sheath to easily and reliably connect and stop the water. The corrosion resistance can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the overall configuration of an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the vicinity of the anchor head in FIG.

FIG. 3 is an enlarged cross-sectional view of the water blocking part in FIG.

[Explanation of symbols]

 1 Deformed PC steel bar 2 Sheath 3 Rust preventive material 4 Coupler 5 Spacer 6 Nut 7 Water stop 7a Water stop member 7b Corrosion protection tape 8 Anchor plate 9 Joint sheath 9a Flange 9b Thin part 9c Thick part 9d Packing groove 10 Water stop packing 11 Bearing pipe 12 O-ring 13 Circular plate 14 Fixing nut 15 Anti-rust cap 16 O-ring 17 Anti-rust material A Drilling G Primary grout

Claims (5)

[Claims] 1. An anchor head for fixing an end of a tensile steel material to a construction wall surface, a free length portion for covering an outer periphery of the tensile steel material with a sheath and a fixing length portion not covered by the sheath in a drilling hole. A permanent anchor having a water blocking portion at the boundary between the free length portion and the fixed length portion, wherein the tensile steel material is a steel material for prestressed concrete (hereinafter referred to as PC steel material) coated with a synthetic resin. Permanent anchor. 2. At the boundary between the free length portion and the fixed length portion,
The permanent anchor according to claim 1, wherein the water blocking member is fitted to the PC steel material, and a water blocking portion is formed between the water blocking member and the end of the sheath which covers the free length portion. 3. The permanent anchor according to claim 1, wherein a spacer for adjusting the arrangement of the tensile steel material in the drilled hole is fitted to the PC steel material of the fixing length portion. 4. The permanent anchor according to claim 1, wherein a nut is fitted to a PC steel material tip portion of the fixing length portion. 5. A sheath covering the free length portion is joined to a through hole of the head anchor plate through a joint sheath,
5. The permanent anchor according to claim 1, 2, 3, or 4, wherein water blocking packings are arranged at least at two locations inside the joint sheath to form a water blocking portion between the joint sheath and the sheath.