JP2955535B2 - Compression anchor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression-type anchor in which a tensile force applied to a tension member at a fixing portion is applied with a compressive force. It is about anchors that settle.

[0002]

2. Description of the Related Art An anchor in which a tension is applied to a tension member of an anchor and the tension acts as a pressure on a fixing portion of the anchor is called a compression type anchor. As an example of the compression type anchor, there is a C-turn removal type anchor as shown in FIG. Removable anchors are not intended for permanent use, but are intended for use as anchors and then withdrawn from the ground.
The turn is a material obtained by folding an intermediate portion of an unbonded tensile material a so that both ends protrude to the surface of the ground, applying the folded portion to a load-bearing body b such as a casting, injecting a grout material c into a drilled hole d, and fixing the material. is there. When removing the tension member a, one end of the tension member a is released and the other end is pulled out from the drilled hole d, and the tension member a is drawn around the load-bearing body b.

In such a C-turn-removable anchor, tension is applied to the tension member a by tensioning both ends of the folded tension member a, and the folded portion of the tension member is applied to the load-bearing body b hooked. , The tension acts as a compressive force toward the ground. In such a C-turn removal type anchor, as shown in the stress distribution diagram shown in the lower part of FIG. 2, a tensile force of 100% acts on the unbonded tensile material a even in that portion. That is, when the tension member a is tensioned on the ground with a tension of 100 kg, a tension of 100 kg acts on the entire length of the tension member a.

[0004]

On the other hand, such a C-turn type anchor may be used as a permanent anchor without assuming removal. However, as a problem of such a C-turn type anchor, there is a problem of the number of tensile members. The number of tensile members used depends on the working conditions and construction conditions at the site.
However, in the case of the C-turn type anchor, since one tensile member is used by folding, the number of tensile members coming out on the ground is always an even number. In other words, if one tensile member is turned over, two tips will come out on the ground, and if two tensile members are used, the tips will be four, if three, six, etc.

[0005] However, in an actual site, an odd number of tension members may be tensioned.
When such a number is used, there is a defect that such a C-turn type permanent anchor cannot be used.
It is also possible to form an odd number of tension members by folding the tip portion of the tension member and hooking it on the load-bearing body, extending only the other end to the ground, and combining with another C-turn type tension member. In the case where only a sharp tip is hooked, it becomes a problem whether the tip can be firmly fixed in the ground. When the hooked portion is formed by bending with a large radius, the fixation is stronger than that of the small bending process, and the original tensile strength of the tensile material can be exerted. However,
In the case of bending with a large radius, the diameter of the hole must be increased. Even if the diameter of the drill hole is increased by only about 5 mm, the construction scale becomes large. Therefore, the construction cost is drastically increased, and it is desirable that the anchor can be fixed in the drill hole having a diameter as small as possible. .

According to the present invention, the number of tensile members can be freely and appropriately selected, and can be fixed even in a small hole having the same diameter as that of the conventional one, and the original tensile load of the tensile member is applied. It is an object of the present invention to provide a compression-type anchor that can be used.

[0007]

SUMMARY OF THE INVENTION A compression type anchor according to the present invention has a small length by exposing a desired length of a tip portion of a tensile member to form a fixed length portion extending from a load-bearing body toward the ground. This secures a portion where the tensile material is fixed in the bore of the diameter.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In a compression type anchor according to the present invention, a tip portion of a tensile member is used as a fixing length portion. As the tensile member, a normal tensile member such as a PC steel strand or a PC steel wire can be used. The part of the tensile material extending in the ground direction is unbonded. The unbonding process is to prevent the adhesive from being attached as a grout material. The unbonding process is to apply grease around the tensile material, or to pass through a thin synthetic resin sheath or the like around the greased material. The above-described fixing length portion is such that the tensile material is exposed as it is without performing such unbonding processing.

[0009] The exposed fixing portion is folded back from the load-bearing body and hooked on the load-bearing body.
The tip of the tensile member is folded in a J-shape like a so-called hook, and the folded portion protrudes a desired length from the desired length load-bearing body and extends in the ground direction when placed in a drilled hole. Things. The length of the turn and extending in the ground direction is preferably about 0.5 to 1 m, but depending on the case, 0.3 m may be sufficient or 2 m or more may be secured. As the load-bearing body, the one used for the conventional compression-type anchor can be used, and a widely used one such as a casting main body having a plurality of reinforcing rods of glass fiber rods protruding therefrom can be used. This load-bearing body may be placed in a deformed sheath made of steel or synthetic resin and having irregularities around the periphery, and a cap may be put on the tip.

[0010] The load-bearing body hooked with the tensile material as described above is inserted into a drilled hole in the ground, and grout material is injected into the drilled hole and fixed. As the grout material, cement milk, mortar, or the like can be used. The fixing length portion at the tip of the tensile material is exposed and adheres to the grout material in the hole. When a portion of the tensile member protruding from the ground is tensioned to apply tension, 100% of the tension acts on the unbonded portion as it is. Since the exposed fixing length is adhered to the surrounding grout material, frictional force acts on the surrounding grout material, and the tension acting on the tensile material gradually decreases, and the fixing length is reduced. It becomes 0% near the tip of the part. In other words, the tension is shared by the exposed fixing length portion extending in the ground direction, so that the original tensile strength of the conventional tensile material can be exerted even by bending with a small radius.

The above-mentioned tensile member may be combined with a C-turn type anchor. As the C-turn type anchor, one in which the intermediate portion is turned back and a desired length of the turned-back portion is used as the exposed fixing length portion can be adopted. The folded part is hooked on the load-carrying body, and this is arranged in the drilled hole, and the unbonded portions at both ends are stretched in the ground direction and protruded to the ground.
Inject grout and fix. The exposed portion of the intermediate portion adheres to the grout material in the hole and becomes a fixed length portion. The number of tensile materials subjected to C-turn processing can be selected as appropriate,
It may be hung on one or more load-bearing bodies, and by using a single anchor with a bent end, an odd number of anchors in which one tensile member is added to an even number of C-turn type tensile members Become.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. In FIG. 1, reference numeral 1 denotes a tension member made of a PC steel wire, and a tip portion of the tension member 1 is a exposed fixing length portion 2, and the other portion is passed through an unbond sheath 3 to unbond. It has been processed. The fixing length portion 2 is folded back, and the folded portion is hooked on the load bearing member 4. The load-bearing body 4 has a main body 5 made of cast metal and a plurality of reinforcing rods 6 made of glass fiber projecting therefrom. The load-carrying body 4 is disposed in a stainless steel deformed sheath 7 and a tip 8 is covered with a cap 8.

The load bearing member 4 and the tensile member 1 as described above are arranged in a hole 9 excavated in the ground. Grout material 1 in drill hole 9
0 is injected to fix the tensile material 1. The exposed fixing length portion 2 of the tensile material 1 protrudes from the load bearing member 4 in the ground direction, and this portion adheres to the grout material 10. As shown in the stress distribution diagram at the bottom of FIG. 1, 100% of the tension acts on the unbonded portion of the tensile material 1 and the exposed portion gradually reduces the tension due to the frictional force. Then, it becomes about 50% at the top of the load-bearing body, and further becomes 0% near the tip of the fixing length portion 2. In other words, the tension is gradually taken over by the bent portion and the exposed fixing length portion 2, so that even if a large tension is applied, the tension is not pulled out.

FIGS. 3 to 5 show an example in which a C-turn type tensile member 12 and the above-described tensile member 1 having a bent end are combined. FIG. 3 shows a case where the tension member 12 with the intermediate portion exposed and applied to the load-bearing body 4 as the fixing length portion 11 and the tensile material 1 whose tip is bent are applied to separate load-bearing bodies 4. FIG. 4 shows a state in which a tensile member 12 having a C-turn and a tensile member 1 having a bent end are hung on one load-bearing body 4. In the case of the embodiment shown in FIGS. 3 and 4, the tips of the three tensile members 1 and 12 project above the ground. FIG. 5 shows that two C-turned tensile members 12 are separately loaded into the load-bearing member 4.
, And the tensile material 1 whose tip is bent is further hung on a separate load-bearing body 4. In this case, five tensile members 1
・ Twelve tips will protrude above the ground.

[0015]

The present invention has the above-described configuration, and can obtain the following effects. Since the tensile material with the bent end was hung on the load-bearing body and settled in the drilled hole, it could be combined with the C-turned tensile material to make the desired number of anchors. It can be constructed as a matching number of anchors. Since the tip is exposed and bent, and the folded portion is fixed in the hole as a fixing length, the fixing length bears tension due to frictional force and can bear even if an original tensile load is applied. Because the fixing length section that extends in the ground direction from the load-bearing body is provided,
Even with small radius bending, it can bear enough tension, and it can be used with conventional small radius drilling,
It can suppress soaring construction costs.

[Brief description of the drawings]

FIG. 1 is an embodiment of an anchor having a bent end according to the present invention.

FIG. 2 is a conventional C-turn type removal type anchor.

FIG. 3 is an example of a combination with a C-turn type tensile member.

FIG. 4 is another example in combination with a C-turn type tensile member.

FIG. 5 is another example in combination with a C-turn type tensile member.

FIG. 6 is an embodiment in which the present invention is used for fixing a slope stabilizing block.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tensile material 2 Fixing length part 3 Unbonded sheath 4 Load-bearing body 5 Main body 6 Reinforcing rod 7 Deformed sheath 8 Tip cap 9 Drilling hole 10 Grout material 11 Fixing length part 12 Tensile material

Claims (2)

(57) [Claims] 1. A desired length of a tip portion of a tensile member is exposed, the exposed portion is hung on a load-bearing body, and folded back from the load-bearing body as a starting point, and the folded-back portion extends from the load-bearing body toward the ground. The load-bearing body with this tension material is inserted into a drilled hole excavated in the ground, grout is injected, and compression is established in the drilled hole. Type anchor. 2. At least one of the tensile members arranged in the drilled hole is exposed at a desired length of a tip portion of the tensile member, and the exposed portion is hung on a load-bearing member to form a load-bearing member. It is folded back from the starting point, and the folded back portion becomes a fixing length portion of a desired length extending from the load-bearing body toward the ground direction. A compression-type anchor that is folded back on the load-bearing body, and the load-bearing body on which these tensile materials are hung is inserted into a drilled hole excavated in the ground, grout is injected and fixed in the drilled hole.