JPH0617858Y2 - Anchor bond sheath - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention relates to a bond sheath of an anchor, and more particularly to a bond sheath of an anchor formed into a so-called deformed shape so as to give a restraining force to a tensile member.

[Prior Art] Conventionally, when anchors are constructed by anchoring a tension material such as an anchor cable in an anchor construction, it has been performed as shown in FIG.

That is, first, a hole 2 is drilled in the natural ground 1, and a P
A tensile member 3 made of a stranded wire of C steel or the like is inserted. The tension member 3 is formed so that only the tip 3a is exposed.
Unbonded sheath 4 such as polyethylene hose, leaving a
Is covered with.

Then, the grout 5 is injected into the space inside the drilled hole 2 and hardened, and the exposed tip portion 3a of the tensile member 3 is fixed and fixed.

After that, the extension side of the tensile member 3 was tensioned with a jack or the like to give prestress.

However, in the case of constructing the anchor in this way, when prestressing the tensile member 3, the grout 5 attached to the outer periphery of the tensile member 3 is also pulled at the same time, and the grout 5 has a shape as shown in the drawing. A lateral crack 6 was generated in a direction orthogonal to the tensile material 3.

Generally, when the width of the lateral crack 6 becomes approximately 0.3 mm or more, groundwater passes through the lateral crack 6 to rust the fixing portion of the tensile member 3 formed by the stranded wire of PC steel or the like. It is known. The rusting of this tensile member 3 is
It may eventually break, and when the tensile member 3 breaks, it will no longer function as an anchor.

Therefore, the tensile member 3 exposed from the unbonded sheath 4
It was conceived to use a bond sheath 7 composed of a straight cylindrical body as shown in FIG.

In this case, first, the bond sheath 7 is inserted into the drilled hole 2 of the natural ground 1, and the tip portion 3 a of the tensile member 3 exposed from the unbond sheath 4 is inserted into the bond sheath 7.
Insert.

Next, the cement paste 8 or the grout 5 is injected into the bond sheath 7, and the space grout 5 in the drilled hole 2 is injected and cured to fix the exposed tip portion 3a of the tensile member 3 and the bond sheath 7. Fix it.

After that, the extension side of the tensile member 3 was tensioned with a jack or the like to give prestress.

However, when the bond sheath 7 made of such a straight cylindrical body is used, the tensile material 3 as shown in the drawing is added to the cement paste 8 solidified in the bond sheath 7.
Vertical cracks 9 and horizontal cracks 6a, 6 along the direction of
b may occur, and these cracks reduced the compressive strength and adhesive strength of the anchor.

Therefore, as shown in FIG. 6, a so-called deformed bond sheath 10 was devised in which the shape of the peripheral wall of the bond sheath was devised.

The deformed bond sheath 10 is formed of a cylindrical body whose peripheral wall is formed to have an uneven shape, and mainly two types of a metal type and a polyethylene type are used.

These deformed bond sheaths 10 not only prevent the tensile member 3 from coming into contact with groundwater, but also form a peripheral wall thereof to have an uneven shape, so that when the tensile member 3 is prestressed, A restraining force is applied to the cement paste 8 or the like injected to fix the tensile member 3 so as to compensate for the strength decrease due to the generation of the vertical crack 9 and the lateral cracks 6a and 6b.

[Problems to be solved by the device]

By the way, in the case of constructing an anchor by using the above-mentioned deformed bond sheath 10 made of metal or polyethylene, there are the following problems.

In the deformed bond sheath 10 made of metal, since the material has a high elastic coefficient, the binding force of the cement paste 8 or the like is strong and the adhesion resistance thereof is large, but the deformed bond sheath 10 itself is rusted due to contact with groundwater. However, there is a problem that it becomes brittle and has a short life.

In contrast to the metallic bond sheath 10, the polyethylene deformed bond sheath 10 has a long life because it does not rust even if it comes into contact with groundwater due to its material, but has a low elastic modulus, so that the cement paste 8 is restrained. There was a problem that the strength was still weak and the adhesion strength was small.

In view of the above points, the present invention provides a bond sheath of an anchor having excellent corrosion resistance, a long life, and a large anchoring force such as cement paste injected to fix a tensile material and a good anchor strength. It is in.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the bond sheath of the anchor of the present invention is formed so that the outer peripheral wall of a cylindrical body made of metal or polyethylene has an uneven shape to form a sheath body. A base cloth such as paper or cloth is wound along the base cloth, and a synthetic resin liquid is applied to the base cloth and dried and cured to cover the outer peripheral wall.

[Action]

According to the above configuration, even if the sheath body is made of metal, the outer peripheral wall of the sheath body is closely covered with the resin-cured base cloth, so that the sheath body has water repellency and the groundwater is metal. Does not come into direct contact with the sheath body, and the sheath body does not rust.

In addition, a polyethylene sheath body with a smaller elastic modulus than a metal sheath body is inferior in the constraining force of the cement paste. By covering the base fabric with the sheath body, the sheath body is not damaged and the restraining force of the sheath body is supplemented. As a result, cracks can be prevented from occurring and the anchor strength is improved.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the bond sheath 20 of the anchor of the present invention comprises a polyethylene sheath body 21 having both ends opened or one end opened and the other end closed, and the entire outer peripheral wall of the sheath body 21. And a base cloth 22 covering the base material.

The sheath main body 21 is formed in a deformed shape in which the peripheral wall of the cylindrical body has an irregular shape, and specifically, the corrugated irregularities in the shape of peaks and valleys are sequentially formed in the longitudinal section of the peripheral wall,
As is clear from FIG. 1, this corrugation has a relatively large undulation of peaks and valleys, and is continuously formed in a spiral shape along the circumferential direction of the peripheral wall.

Further, the outer surface of the peripheral wall of the sheath body 21 having the uneven shape is covered with the base cloth 22 by winding the entire surface along the uneven shape. The base cloth 22 is formed of a flexible thin-walled sheath by paper or cloth, and when the sheath body 21 is wound and covered, the uneven shape is maintained so as not to be flattened. The outer peripheral surface is covered with a substantially uniform thickness.

In this coating, a paper sheet having a predetermined width, for example, is used as the base cloth 22, and the paper sheet is wound around the outer peripheral wall of the sheath main body 21 in a state where the paper sheet is first wet and spirally overlapped with each other. Then, the uneven shape is maintained so that the uneven shape is not lost.

When the above-mentioned paper sheet dries, it cures while sticking to the sheath body 21, but if it remains as it is, the adhesive effect is poor, so
Next, for example, a polyurethane resin liquid is applied to this paper sheet, and a sufficient amount is impregnated to adhere and cure the sheath body 21. As a result, the paper sheet is firmly adhered to the outer peripheral wall of the sheath body 21 while maintaining the uneven shape of the sheath body 21 in a state where the sheath body 21 is reinforced. This makes it waterproof.

When the synthetic resin liquid is applied to the paper sheet, the paper sheet is directly immersed in the synthetic resin liquid without being applied as described above, and the sheath body 2 is sufficiently impregnated with the resin.
It may be wound around 1 to be covered and adhesively cured.

When an anchor is constructed using the bond sheath 20 of the present invention having the above-described structure, the process is as shown in FIG.

First, a hole 25 is drilled in the ground 24, and the bond sheath 20 of the present invention is inserted into the hole 25. As described above, when one end of the bond sheath 20 is open and the other end is closed, the closed end 20a is inserted deep inside the drilled hole 25. Before the bond sheath 20 is inserted into the drilled hole 25, the base cloth 2 is attached to the outer peripheral wall of the sheath body 21.
2 is wound and covered with resin.

Next, the unbonded sheath 26 is placed in the bond sheath 20.
The distal end portion 27a of the tension member 27 exposed from is inserted.

Then, the cement paste 2 is placed in the bond sheath 20.
8 or grout 29 is injected, and
The grout 29 is injected into the space in the inside of the No. 5 and hardened, and the exposed tip portion 27a of the tensile material 27 and the bond sheath 20 are cured.
Fix and fix.

Then, the extension side of the tension member 27 is tensioned with a jack or the like to give prestress.

As described above, the sheath body 21 constituting the bond sheath 20 of the anchor of this embodiment is formed of polyethylene, and the base cloth cured with resin covers the outer peripheral wall thereof. Therefore, it is highly waterproof and does not allow groundwater to penetrate.

Further, the restraining force F of the cement paste 28 or the like injected to fix the tension material 27 inserted into the sheath body 21 is such that the sheath body 21 is formed in an irregular shape and is made of resin in that state. The hardened base cloth 22 adheres to and coats the outer peripheral wall, so that the base cloth 22 is supplemented and becomes large,
Its adhesion strength is increased.

Therefore, according to this example, good corrosion resistance is exhibited as a whole, and a long life is provided.

FIG. 3 shows another embodiment of the present invention, which is a sheath body 21 '.
Is made of a so-called spiral sheath made of metal. The sheath body 21 'is formed into a long tubular body by bending both ends of a band-shaped metal plate having a constant width in opposite directions, and twisting the both ends in a spiral shape to engage the both ends. Therefore, as shown in the drawing, the outer peripheral wall of the sheath main body 21 'is formed with convex stripes at regular intervals in the meshing portion, and has an irregular shape as a whole.

When the metal sheath body 21 'is coated with the base cloth 22, the base cloth 22 is wound around the outer peripheral wall in a moistened state in advance, as in the above-described embodiment, and the synthetic resin is dried. The liquid may be applied and adhered, or the base cloth 22 may be directly immersed in the synthetic resin liquid and coated and adhered in that state.

As described above, when the base cloth 22 is in close contact with the sheath body 21 'while being hardened by the synthetic resin, the water repellency of the base cloth 22 has a waterproof effect, and the sheath body 2 made of metal.
Groundwater is prevented from penetrating to 1 ', and corrosion resistance is excellent.

[Effect of device]

As described above, according to the bond sheath of the anchor of the present invention, it has a long life due to good corrosion resistance, and has a large anchoring force of cement paste or the like injected to fix the tensile material and a good anchor strength. Exerts an excellent effect.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of an anchor bond sheath of the present invention, and FIG. 2 is a longitudinal sectional view showing an anchor construction state using the anchor bond sheath of FIG. FIG. 3 is a partially broken perspective view showing another embodiment of the bond sheath. FIG. 4 is a side sectional view showing a conventional anchor construction structure that does not use a bond sheath, FIG. 5 is a side sectional view showing a conventional bond sheath, and FIG. 6 is a side sectional view showing a conventional deformed bond sheath. 20 ... Anchor bond sheath; 21, 21 '... Sheath body; 22 ... Base cloth.

Claims (1)

[Scope of utility model registration request] 1. A deformed bond sheath main body, which is made of a metal or polyethylene cylindrical body connected to a straight unbonded sheath and whose peripheral wall is spirally formed in a corrugated shape, paper, cloth, etc. And a base cloth adhesively coated along the outer peripheral wall of the deformed bond sheath body with a resin such as polyurethane and the like, and a bond sheath of the anchor.