JP3148807B2 - Ground anchor anchoring head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground anchor buried in the ground to fix a structure on the ground, and more particularly to a head anchored on a structure or the like by a wedge. Things.

[0002]

2. Description of the Related Art Tensile materials such as steel strands are bundled, buried in a drilled hole in the ground, the tip is fixed at the bottom of the drilled hole, and the part coming out of the ground is fixed to a structure or the like. Therefore, ground anchors for fixing structures and the like on the ground are used. As shown in FIG. 7, the tensile material a of the ground anchor is covered with an unbonded sheath b made of thin-walled polyethylene or the like in order to give a prestressing force. This is because the unbonded sheath b does not adhere to the hardening material injected into the drilled hole and allows the intermediate portion, which is a free long portion, to freely extend when a prestressing force is applied. The unbonded sheath b is made of a tensile material a
Also has the effect of preventing the rust-preventive oil c applied on the periphery from falling. However, since the tip protruding above the ground is fixed to the anchor head f on the structure d or the like by the wedge e, the tension member a is exposed without covering the unbond sheath b.

[0003] As described above, the unbond sheath b reaches only before the anchor head f in order to be fixed by the wedge e. That is, a slight gap g occurs between the ground-side end of the unbonded sheath b and the anchor head f. The steel sheath h for protecting the inner periphery of the hole through which the anchor formed in the structure d passes is filled with the rust-preventive oil i. There is a possibility that the oil i leaks out and the oil level of the rust-preventive oil i drops. If the oil level decreases, the above-mentioned exposed tensile material a before the anchor head b
However, there is a possibility that the rust-preventive oil i is not protected by the gap g and remains unprotected. If water intruding from outside touches here, there is a danger of an accident that the tensile member a rusts and breaks.

[0004] In order to solve the above-mentioned problems, the present invention is to provide a ground anchor fixing head in which a portion corresponding to a gap generated between an anchor head and an unbonded sheath is always protected by rust-preventive oil. The purpose is to provide.

In the anchoring head of the ground anchor according to the present invention, an unbonded sheath fitting portion is formed on the ground side of the anchor head, and the tip of the unbonded sheath reaches the inside of the fitting portion and prevents the unbonded sheath from entering the fitting portion. The rust oil is filled, and the gap formed between the ground side end of the unbonded sheath and the anchor head is always immersed in the oil.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The anchor head of a ground anchor according to the present invention is provided with an unbonded sheath fitting portion for leading an end of an unbonded sheath to a steel anchor head for fixing a protruding portion of a tensile member from the ground. Things.
A single or a plurality of tensile material insertion holes for passing a tensile material are passed through the anchor head. A part of the tensile material insertion hole on the ground surface side is a wedge arrangement part whose diameter gradually increases. Also, part of the ground material side of the tensile material insertion hole,
It is an unbonded sheath fitting portion whose diameter gradually increases. The anchor head is placed on a support plate having an anchor hole in the center, and the tip of the tensile material embedded and fixed in the ground is passed through the tensile material insertion hole of the anchor head. Conventional tensile materials such as PC steel strands and PC steel wires can be widely used as the tensile material. The unbonded sheath is covered around the free length part of the tensile material coated with rust preventive oil, but the part passing through the tensile material insertion hole of the anchor head is exposed,
The unbonded sheath is interrupted just before the anchor head on the ground side. A wedge is arranged on the wedge-arranged portion of the anchor head to hold the tension member.

When the tension member is tensioned, the unbonded sheath is moved to the ground side by the frictional force due to the frictional force, and the ground side end of the unbonded sheath reaches the unbonded sheath fitting portion. The grease-like rust-preventive oil may be filled in advance in the unbonded sheath fitting portion, but when the tensile material is tensioned, the rust-preventive oil around the unbonded sheath is scraped off in the unbonded sheath fitting portion, The inside of the fitting portion is filled. The rust-preventive oil is also filled in the sheath that is continuously fixed to the support plate, but if the oil inside escapes due to an accident, the end of the unbonded sheath is rust-proof oil inside the unbonded sheath fitting section. Because it is immersed in water, there is no contact with water from outside.

[0008] An oil cap is placed so as to cover the ground side of the anchor head, and the oil cap is filled with rust-preventive oil. Even if the oil in the sheath escapes due to an unexpected accident and further drops to the oil in the unbonded sheath fitting portion of the anchor head, the oil in the oil cap falls and fills the fitting portion. That is, the oil in the oil cap drops and fills the fitting portion. That is, the oil in the oil cap flows down through the gap between the wedges due to gravity and passes through the tensile material insertion hole, and is replenished into the unbonded sheath fitting portion.

The inner peripheral surface of the unbonded sheath fitting portion may be formed in a tapered shape so that the diameter gradually increases as approaching the ground side surface. When the tension material is tensioned and the unbonded sheath is pulled toward the anchor head, the end of the unbonded sheath is guided to the tapered inner peripheral surface, and reliably enters the unbonded sheath fitting portion. The minimum diameter of the tensile material insertion hole is the same as the diameter of the tensile material, or 1-3
mm. The thickness of the unbonded sheath is 1 to
It is about 1.2 mm, and if it is 3 mm or less, an accident that the unbonded sheath is drawn into the wedge arrangement portion does not occur.

[0010]

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 an anchor head, and a plurality of tensile material insertion holes 2 that pass from the ground side to the ground side.
Are penetrating more than one. Part of the tensile material insertion hole 2 on the ground side
A wedge arrangement portion L1 whose inner diameter gradually increases toward the ground side is provided with a split wedge 3. The unbonded sheath fitting portion L2 in which a part of the tensile material insertion hole 2 on the ground side has an inner diameter gradually increasing toward the ground side.
It has become. In the embodiment shown in FIGS. 1 to 4, the tensile material insertion hole 2 is formed by a wedge having a position portion L1 and an unbonded sheath fitting portion L.
There are two parts. The minimum hole diameter of the tension member insertion hole 2, that is, the diameter w of the contact point between the wedge arrangement portion L1 and the unbond sheath insertion portion L2 is formed to be equal to or slightly larger than the diameter of the tension member 11 described later. By doing so, the unbonded sheath 12 is moved to the wedge disposition portion L
The unbonded sheath 12 does not hinder the tension member 11 from being caught by the wedge 3.

In FIG. 1, reference numeral 6 denotes a structure constructed on the ground. An anchor hole 7 penetrates the structure 6, and a support plate 8 having an anchor hole 9 penetrated at the center is fixed to the surface of the structure 6. is there. A sheath 10 is fixed to the supporting plate 8 continuously along the inner peripheral surface of the anchor hole 7. Ground anchor tensile material 11 buried and anchored in a borehole formed in the ground
Project through the anchor hole 7 to the ground. A PC steel strand is used as the tensile member 11, and an unbonded sheath 12 made of polyethylene is covered from the free length portion to the vicinity of the tip.

With the protruding portion of the tension member 11 from the ground passing through the tension member insertion hole 2, the anchor head 1 is
Place on top of. The sheath 10 is filled with a rust-preventive oil 14. When the tension member 11 is tensioned in this state, the unbond sheath 12 is entangled and slightly moves to the ground side, and the ground side end of the unbond sheath 12 is inserted into the unbond sheath fitting portion L2 of the anchor head.
Get inside. The rust-preventive oil 14 applied around the tensile material 11 is peeled off, and the unbonded sheath fitting portion L2
Fill inside. The tensile member 11 is sandwiched between the wedges 3.

In the above-described embodiment, when the sheath 10 and the like are damaged and the inner rust-preventive oil 14 leaks out, the oil level of the internal oil 14 drops, but the end of the unbonded sheath 12 Oil 1 of unbonded sheath fitting part L2
4, the water that has entered from the outside does not touch the gap between the unbonded sheath 12 and the anchor head 1. So as to cover the anchor head 1
An oil cap 13 is mounted on the support plate 8 with bolts, and the inside is filled with rust-preventive oil 14. As shown in FIG. 3, the oil cap 13 may be of a type in which an internal female screw 16 is screwed into a male screw 15 on the outer periphery of the anchor head. When the oil 14 in the sheath 10 leaks, the rust-preventive oil 14 in the oil cap 13 falls along the tensile material insertion hole 2 due to gravity, and fills the unbonded sheath fitting portion L2.

FIG. 4 shows another embodiment, in which the unbonded sheath fitting portion L2 is formed in a concave shape having the same diameter in the depth direction. FIG. 5 shows the wedge arrangement portion L
This is an example in which a straight portion L3 having a straight inner peripheral surface is provided between the first portion 1 and the unbonded sheath fitting portion L2. FIG. 6 shows an example in which a curved surface portion L4 bulging inward is provided between the wedge arrangement portion L1 and the unbonded sheath fitting portion L2. In the embodiment of FIGS. 1 to 4, there is no straight portion L3 or such a curved surface portion L4, and the wedge arrangement portion L1 is not provided.
And the unbonded sheath fitting portion L2 directly and sharply contact the mountain shape. When the tension member 11 passed through the insertion hole 2 located outside the anchor head 1 is bundled in the sheath 10, the tension member 11 sometimes breaks or breaks in contact with the angled portion. By having such a straight portion L3 and a curved surface portion L4, the inner peripheral surface of the insertion hole 2 is not damaged on the side surface of the tensile member 11, and the risk of tearing is significantly reduced. The minimum hole diameter of the straight portion L3 and the curved surface portion L4 is the tensile material 1
1 or slightly larger.

[0015]

The present invention has the above-described configuration, and can obtain the following effects. The anchor head is provided with an unbonded sheath fitting part, and the end of the unbonded sheath is reached inside this fitting part and filled with rust preventive oil, so that water may touch the gap between the unbonded sheath and the anchor head. No anchor rupture accidents occur. Since the oil is covered with an oil cap covering the anchor head, the oil travels through the tensile material insertion hole to fill the unbonded sheath fitting part, and always fills the gap between the unbonded sheath and the anchor head with water. Do not touch. By forming the inner peripheral surface of the unbonded sheath fitting portion into a tapered shape, the unbonded sheath will surely enter the fitting portion when the tension member is tensioned. Since the minimum hole diameter of the tensile material insertion hole is the same as the tensile material or only 1 to 3 mm larger than the tensile material, the unbonded sheath is not drawn into the wedge arrangement portion, and the unbonded sheath does not hinder the clamping of the tensile material by the wedge. . By providing the straight portion or the curved surface portion, the inner peripheral surface of the insertion hole does not damage the side surface of the tensile member, and the risk of tearing is significantly reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view of the embodiment of FIG.

FIG. 3 is a sectional view showing another embodiment.

FIG. 4 is a partial sectional view of an anchor head showing another embodiment.

FIG. 5 is a partial sectional view of an anchor head showing another embodiment.

FIG. 6 is a partial sectional view of an anchor head showing another embodiment.

FIG. 7 is a sectional view of a fixing head of a conventional anchor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anchor head 2 Tensile material insertion hole 3 Wedge 6 Structure 7 Anchor hole 8 Support plate 9 Anchor hole 10 Sheath 11 Tensile material 12 Unbonded sheath 13 Oil cap 14 Rust prevention oil L1 Wedge arrangement part L2 Unbonded sheath fitting part L3 Straight part L4 Curved surface

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E02D 5/74-5/80

Claims (1)

(57) [Claims] 1. A wedge-arranged portion having a gradually increasing diameter on one surface side of one or a plurality of tensile material insertion holes penetrating through an anchor head, and an unbonded sheath having a gradually increasing diameter on a ground side portion. And the minimum hole diameter between the wedge arrangement portion and the unbonded sheath fitting portion is set to be the same as the tensile material or 1 to 3 mm larger, and placed on a support plate having an anchor hole centered on the anchor head. , The tip of the tensile material buried and fixed in the ground is passed through the tensile material insertion hole of the anchor head, tensioned and sandwiched by the wedge arranged in the wedge arrangement part, and the unbond arranged on the outer periphery of the free length part of the tensile material The ground-side tip of the sheath is brought to the unbonded sheath insertion part, and the unbonded sheath is prevented from being pulled in further by the minimum hole diameter of the tensile material insertion hole,
The anchor section of the ground anchor that is filled with rust-preventive oil inside the unbonded sheath fitting section, covers the ground side of the anchor head with an oil cap, and is filled with rust-preventive oil.