JP2003090040A - Anchor tension member and construction method of anchor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anchor tension member and a construction method of an anchor capable of obtaining required strength by shortening the length of a borehole and a shorter anchor tension member. SOLUTION: The anchor tension member 1a includes an anchor length section 11 for anchoring in the ground and a free length section 12 transferring tension to the anchor length section, and the anchor length section is so permanently deformed that a projection section to the longitudinal direction of the anchor length section becomes larger than that of the free length section. The anchor length section is permanently deformed to enable it to come into contact with a hardener in a wider area by comparison with a united anchor length section. After the anchor tension member 1b has been inserted into the anchor hole, an operating wire rod 61 is pulled out to enable the anchor length section 11 to widen in the shape of a lantern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anchor tension material used for an anchor anchored in the ground or a structure and a method for constructing an anchor using the anchor tension material.

[0002]

2. Description of the Related Art Conventionally, a hole is drilled in the ground, an anchor tension material such as PC steel wire is inserted into the anchor hole, and the anchor tension material and the ground are integrated with a solidifying material such as cement milk. A method of constructing an anchor was used. The anchor is composed of a fixed length portion moored to the ground and a free length portion that transmits a tensile force to the fixed length portion. The pull-out proof strength of the anchor is determined by the smaller one of the adhesive force between the solidified material and the ground and the adhesive force between the anchor tensile material and the solidified material. These adhesive forces are proportional to the area of contact between the solidifying material and the ground or the anchor tension material. Therefore, the length of the fixing long portion is adjusted in order to secure the necessary pull-out resistance of the anchor. Further, since the frictional stress with the solidifying material is different depending on the ground, the ground where the fixing long portion is arranged may be dug deep into the ground so that the ground becomes hard.

[0003]

The above-mentioned conventional anchor tension member and anchor construction method have the following problems. <B> PC steel stranded wire is manufactured by twisting a plurality of strands (tensile material), but only the strand surface appearing on the surface comes into contact with the solidifying material. Therefore, in order to increase the contact area with the solidifying material, it is necessary to increase the length of the anchoring long portion of the anchor tension material. The longer the anchor tension material, the higher the material cost. <B> In order to increase the adhesive force between the solidifying material and the ground, it is necessary to increase the length of the anchor fixing portion. If the fixing long portion becomes long, the drilling length naturally becomes long, and the excavation cost increases. <C> In the case of short anchors, the number of anchor tension members may be increased or the length of the fixing long portion may be increased in order to increase the adhesion area of the anchor tension member and the solidifying material. In some cases, useless anchor tension material is used.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems of the prior art, and provides an anchor tension member which has a short drilling length and which can obtain a desired pull-out strength with a short anchor tension member. The purpose is to provide a method of constructing an anchor. Another object of the present invention is to provide an anchor tension material and an anchor construction method capable of maximizing the yield strength of the anchor tension material. It is an object of the present invention to provide a method of constructing an anchor that can be more easily constructed and has high pull-out resistance. The present invention achieves at least one of these objectives.

[0005]

In order to achieve the above object, the anchor tension member of the present invention has a fixing length portion for fixing to the ground and a free length portion for transmitting a tensile force to the fixing length portion. An anchor tension material having, wherein the anchor tension material is configured by bundling a plurality of tension materials, and the projected cross section in the longitudinal direction formed by the outer shape of the cross section of the fixing long section is the cross section of the free long section. It is characterized in that the fixing long portion is permanently deformed so as to be larger than a projection cross section formed by the outer shape portion in the longitudinal direction. Since the fixing long portion is permanently deformed and expanded, the fixing long portion can come into contact with the solidifying material over a wider area than in the case of being bound.

In the above anchor tension material,
The size of the projection section in the longitudinal direction formed by the outer shape of the cross section of the fixing long section and the size of the projection section in the longitudinal direction formed by the outer section of the cross section of the free length section are temporarily controlled by a temporary fastener that can be removed by remote control. Can be substantially the same. That is, by reducing the cross section of the fixing long portion when the fixing long portion is inserted with a temporary fastener such as a cap, it is possible to easily insert the widened anchor tension member into an anchor hole having a small diameter.
The cap may be removed after inserting the anchor tension member.

An anchor tension member having a fixing length portion for fixing to the ground and a free length portion for transmitting a tensile force to the fixing length portion, wherein the anchor tension member is formed by bundling a plurality of tension members. It is also possible to connect the tip of the operation wire rod that can be pulled out at the end of the free length portion on the anchor head side to the tip of the fixing length portion, and bind the boundary between the free length portion and the fixing length portion. it can. When the operation wire rod is pulled out after the anchor tension member having such a structure is inserted into the anchor hole, the fixing length portion is widened like a lantern.

According to the method of constructing an anchor of the present invention, an anchor hole having a larger inner diameter at a position where a fixed length portion of an anchor tension member is arranged is larger than an inner diameter at a position where a free length portion is arranged, and the anchor hole is formed in the anchor hole. The anchor tension member according to any one of claims 1 to 3 is inserted, and a projected cross section in a longitudinal direction formed by an outer shape portion of a cross section of the fixing long portion is a length formed by an outer shape portion of the cross section of the free length portion. In this method, a pull-out resistor is formed so as to be larger than the projected cross section in the direction, and the fixing long portion and the solidified material filled in the anchor hole are formed.

Here, when the temporary fastening member is attached to the tip of the anchor tension member, the fixing long portion is widened by removing the temporary fastening device by remote control.

Further, when the fixing long portion is configured to be compressible in the longitudinal direction by the operation wire, the fixing long portion is fixed by pulling out the operation wire at the end of the free length portion on the anchor head side. Widen. Further, the anchor hole may be a widened hole in which the entire length of the anchor hole is matched with the inner diameter of the fixing long portion.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

<A> Anchor Tensile Material The anchor tension material 1 is a fixing long portion 11 for fixing to the ground or a structure, and a tension force acting from the anchor mooring portion 13 and the like is freely transmitted to the fixing long portion 11. It has a long portion 12.
The fixed length portion 11 and the free length portion 12 are usually composed of a continuous PC steel strand, a deformed PC steel rod, a reinforcing bar, or the like. The anchor tension member 1a shown in FIG. 1 is formed by bending a single PC steel stranded wire formed by twisting a plurality of strands (tensile members) into a U-shape. In addition to this, one PC steel wire may be used without being bent, or a plurality of PC steel wires may be bundled and used.

<B> Fixing long portion The fixing long portion 11 of the anchor tension member 1 is a portion for transmitting the tensile force of the anchor tension member 1 to the hole wall formed in the ground or the like through the solidifying material 3. . In the fixing length portion 11, the contact area between the solidifying material 3 and the anchor tension material 1 should be as wide as possible. This is because the magnitude of the adhesive force of the fixing long portion 11 is proportional to the width of the contact area with the solidifying material 3. In the present invention, the adhesive strength is increased by expanding the fixing length portion 11 beyond the free length portion 12.

An example of a single PC steel stranded wire bent in a U shape will be described below (see FIG. 1). PC steel stranded wire is a wire rod formed by twisting a plurality of strands (tensile members), and not all surfaces of the strand are exposed. Therefore, the exposed area is widened by unraveling the PC steel wire of the fixing long portion 11. However, it cannot be said that just by unraveling, the elastic properties of the strands cause the strands to come together again and sufficiently come into contact with the solidifying material 3. Therefore, it is permanently deformed so as to be fixed in a state where the wire is spread out from the unraveled PC steel. By doing so, each wire comes into contact with the solidifying material 3 over the entire circumference, and the adhesive force of the anchor tension material 1a can be increased. That is, the fixing long portion 11 of the anchor tension member 1a is permanently deformed, so that the inside or the inner surface of the anchor tension member 1a can come into contact with the solidifying material 3.

<C> Anchor Hole The anchor hole 2 is an excavation hole for inserting the anchor tension member 1. The anchor hole 2 is widened near the location where the anchoring long portion 11 of the anchor tension member 1 is arranged, if necessary. As a method of widening excavation, a method of widening by the pressure of water vapor generated from the crushing agent 81, a method of widening by exploding or expanding explosive or the like at a predetermined place, and a water jet ejecting laterally at a predetermined place are used. There are a method of injecting and widening, a method of widening a predetermined portion using an excavator having a known widening blade, and the like. Also,
The hole diameter required by the fixing length portion 11 may be secured over the entire length of the anchor hole 2b. In this case, it is not necessary to perform widening excavation depending on the location (see FIG. 6).

The method of constructing the anchor of the present invention will be described below with reference to the drawings.

<A> Anchor hole drilling Using the casing 7, a hole is drilled to a predetermined depth. After drilling, the casing 7 is pulled out from the place where the fixing long portion 11 is arranged to expose the ground. The crushing agent 81 is loaded in the portion that becomes the fixing long portion 11. A padding 82 such as sand is filled above the crushing agent 81 so that the destructive force of the crushing agent 81 does not escape. A lead wire 83 is connected to the crushing agent 81 so that the reaction of the crushing agent 81 can be started by remote control (see FIG. 5). After forming the widened portion 21 with the crushing agent 81, the padding 82 is removed by blowing compressed air or excavating.

<B> Insertion of anchor tension material The anchor tension material 1a is inserted into the anchor hole 2a. It is preferable that the tips of the anchor tension members 1a be bundled by a temporary stopper 41 for easy insertion. Temporary stopper 41
It is preferable that the operation rod 42 or a pipe member be attached to the anchor so that the anchor tension member 1a can be removed after being inserted into the anchor hole 2a. For example, a cap is used as the temporary fastener 41, and the anchor tension member 1 is placed at a predetermined position.
After arranging a, the cap is pierced by the operating rod 42 and removed from the anchor tension member 1a. Since the fixed length portion 11 of the anchor tension member 1a is permanently deformed so as to expand if there is no restraint, it spreads into the anchor hole 2a when the restraint of the temporary fastener 41 is released (see FIG. 1).

<C> Injection of solidifying material A solidifying material 3 such as cement milk or mortar is injected into the anchor hole 2a in which the fixing long portion 11 of the anchor tension member 1a is arranged. The solidifying material 3 is injected using the injection pipe 31 or the like. If the anchor hole 2a has a small diameter and the injection pipe 31 cannot be inserted in addition to the anchor tension member 1a, the injection may be performed before inserting the anchor tension member 1a. When the solidifying material 3 is hardened, the fixing long portion 11 of the anchor tension member 1a is fixed to the hole wall of the anchor hole through the solidifying material 3.

[0020]

[Other Embodiments]

<A> Forced widening method (FIGS. 3 and 4) There is a method of forcibly widening the fixing long portion 11 of the anchor tension member 1b after inserting it into the anchor hole 2. In this method, first, the PC steel wire of the fixing length portion 11 is unwound to facilitate widening. The boundary between the fixed length portion 11 and the free length portion 12 is bound by the binding tool 5 so that the wire of the PC steel of the free length portion 12 does not widen. A plurality of the tying members 5 are arranged on the free length portion 12 of the anchor tension member 1b as required. Then, for example, the end portion of the operation wire rod 61 formed in a U shape and the end portion of the anchor tension member 1b on the fixing long portion 11 side are connected by a connecting tool 62 (see FIG. 3). If the operation wire rod 61 is pulled out from the end of the free length portion 12 in this state, the operation wire rod 61 moves in the direction A of FIG. 4, the distance between the connecting member 62 and the binding tool 5 is reduced, and the fixing length portion 11 is widened. When the anchor tensile member 1b is permanently deformed in this expanded shape by this operation, it is not necessary to fix the operation wire rod 61, but when the expansion deformation returns, fix the operation wire member 61 at least until the solidifying material 3 is hardened. Keep it.

<B> When the anchor hole is not widened (FIG. 6) The entire length of the anchor hole 2b can be excavated in accordance with the shape of the widened fixing long portion 11. In this case, it is not necessary to widen the anchor hole 2b at a predetermined position, and it is sufficient to excavate the anchor hole 2b with a constant diameter. Thus, the anchor hole 2 is aligned with the portion where the projected cross section of the anchor tension member 1a is the largest.
When b is formed, the anchor length member 1a of the anchor tension member 1a
1 can be inserted into the anchor hole 2b while being unfolded. However, in this case, the free length portion 12 is the anchor hole 2b.
The spacer 9 is preferably attached to the free length 12 such that it is located approximately in the center of.

[0023]

EFFECTS OF THE INVENTION Since the anchor tension member and the method of constructing the anchor of the present invention are as described above, the following effects can be obtained. <A> The contact area between the anchor tension material and the solidifying material is increased by widening the fixing long portion of the anchor tension material. Therefore, a desired adhesive force can be obtained without extending the fixing length portion, which is economical. Further, even if the lengths of the fixing long portions are the same, the adhesive strength becomes larger than in the conventional case, so that the anchor yield strength can be increased. <B> By widening the anchor hole of the fixing long portion, a desired anchor proof stress can be obtained even if the fixing long portion is short.
Therefore, the drilling length can be shortened and it is economical. Further, by widening the anchor hole, the contact area between the solidifying material and the ground becomes wider, and an anchor having a high pulling resistance can be constructed even on the ground where a large circumferential friction resistance cannot be secured.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a method for constructing an anchor of the present invention.

FIG. 2 is a side view of the anchor tension member of the present invention.

FIG. 3 is a side view of the anchor tension member before widening in the case of forcibly widening the anchor.

FIG. 4 is a side view at the time of widening the anchor tension member in the case of forcibly widening the anchor.

FIG. 5 is a cross-sectional view of an embodiment when constructing a widened portion of an anchor hole.

FIG. 6 is a cross-sectional view when an anchor tension member is arranged in an anchor hole having no widened portion.

[Explanation of symbols] 1 ... Anchor tension material 11 ... Fixed long section 12 ... Free length section 2 ... Anchor hole 21 .. Widening part 3 ... Solidifying material 41..Temporary fasteners 42 ... Operating rod 5: Binding tool 61..Operating wire rod 62..Connectors

   ─────────────────────────────────────────────────── ─── Continued front page    (71) Applicant 000229128             Nippon Zenith Pipe Co., Ltd.             1-10-5 Iwamotocho, Chiyoda-ku, Tokyo (72) Inventor Hiroshi Yoshida             561 Mizushima, Oyabe City, Toyama Prefecture (72) Inventor Kazuo Minami             13-33 Minamitaikoyama, Kosugi Town, Imizu District, Toyama Prefecture (72) Inventor Toshio Kubota             Niigata Prefecture Niigata City Toriyano 3-14-13 Stock             Company Civil F-term (reference) 2D041 GA01 GB01 GC02 GC14

Claims (7)

[Claims] 1. An anchor tension member having a fixing length portion for fixing to the ground and a free length portion for transmitting a tensile force to the fixing length portion, wherein the anchor tension member is formed by bundling a plurality of tension members. The fixing length is permanently deformed so that the projected cross section in the longitudinal direction formed by the outer shape of the cross section of the fixing length is larger than the projected cross section in the longitudinal direction formed by the outer shape of the cross section of the free length. Anchor tension material. 2. The anchor tension member according to claim 1, wherein a projected portion in a longitudinal direction formed by an external portion of the cross section of the fixing length portion and a contour of the cross section of the free length portion by a temporary fastener which can be detached by remote control. An anchor tension member characterized in that the sizes of the projection cross sections formed in the longitudinal direction of the parts are temporarily made substantially the same. 3. An anchor tension member having a fixing length portion for fixing to the ground and a free length portion for transmitting a tensile force to the fixing length portion, wherein the anchor tension member is formed by bundling a plurality of tension members. The tip of the operation wire that can be pulled out at the end of the free length portion on the anchor head side is connected to the tip of the fixing length portion, and the boundary between the free length portion and the fixing length portion is bound. Anchor tension material. 4. An anchor hole having an inner diameter larger than an inner diameter of a portion where the fixed length portion of the anchor tension member is arranged is formed, and the anchor hole is formed in the anchor hole. The anchor tension member described in 1 is inserted, and the projection cross section in the longitudinal direction formed by the outer shape of the cross section of the fixing length is larger than the projection cross section in the longitudinal direction formed by the outer shape of the cross section of the free length. And forming a pull-out resistor with the fixing long portion and the solid material filled in the anchor hole. 5. An anchor hole according to claim 2, wherein an anchor hole having an inner diameter larger than an inner diameter of a portion where the fixed length portion of the anchor tension member is arranged is larger than an inner diameter of a portion where the free length portion is arranged. A method of constructing an anchor, in which a tension member is inserted, the temporary fastener attached to the anchor tension member is remotely removed, and the pull-out resistor is formed by the fixing length portion and the solid material filled in the anchor hole. . 6. An anchor according to claim 3, wherein an anchor hole having an inner diameter larger than an inner diameter of a portion where the fixed length portion of the anchor tension member is arranged is larger than an inner diameter of a portion where the free length portion is arranged. Insert a tension member, and widen the fixing length portion by pulling out the operation wire at the end of the free length portion on the anchor head side, and by the fixing length portion and the solid material filled in the anchor hole. Anchor construction method to form pull-out resistor. 7. An anchor hole is formed, and the anchor tension member according to claim 1 is inserted into the anchor hole so that the free length portion is arranged substantially in the center of the anchor hole. A method for constructing an anchor, wherein a pull-out resistor is formed with the solid material filled in the anchor hole.