JPH0617857Y2 - 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 in a so-called irregular shape so as to give a restraining force to a tensile member.

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

As shown in the figure, first, a ground hole 1 is drilled 2, and this hole 2 is drilled.
A tensile member 3 made of PC steel stranded wire or the like is inserted therein. The tensile member 3 is covered with an unbonded sheath 4 such as a polyethylene hose so that only the tip 3a is exposed.

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, so that the tensile force shown in the grout 5 is reduced. A lateral crack 6 was generated in a direction orthogonal to the material 3.

Generally, when the width of the lateral crack 6 is 0.3 mm or more, groundwater can pass through the lateral crack 6 to rust the fixing portion of the tensile member 3 formed of the stranded wire of PC steel or the like. Are known. The rusting of the tensile member 3 may eventually cause its rupture, and when the tensile member 3 ruptures, it no longer serves as an anchor.

Therefore, the tensile member 3 exposed from the unbonded sheath 4
It was conceived to use the bond sheath 7 composed of a straight cylindrical body as shown in FIG. 5 in order to protect the tip portion 3a of the above from the ground water.

As shown in the figure, when constructing an anchor using the bond sheath 7, first, the bond sheath 7 is inserted into the drilled hole 2 of the natural ground 1 and the bond sheath 7
The tip portion 3a of the tensile member 3 exposed from the unbonded sheath 4 is inserted therein.

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.

As shown in the figure, the deformed bond sheath 10 is formed of a tubular body whose peripheral wall is formed in a spiral corrugation, and there are mainly two types, that is, a metallic one and a polyethylene one.

These deformed bond sheaths 10 not only prevent the tensile member 3 from coming into contact with groundwater, but also form a spiral corrugation on the peripheral wall of the tensile member 3 when prestressing the tensile member 3. 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, the two types of deformed bond sheaths 10 as described above are used.
There are the following problems when adopting to build an anchor.

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-mentioned problems, an object of the present invention is to provide an anchor having a long life due to good corrosion resistance and also having a large anchoring force such as cement paste injected to fix a tensile material and having good anchor strength. Providing a bond sheath.

[Means for Solving the Problems]

In order to achieve the above object, the bond sheath of the anchor of the present invention comprises a resin cylindrical body continuously connected to a straight unbonded sheath, the peripheral wall of which has a spiral shape and is shaped into a wavy corrugated main body of the deformed bond sheath. And a spiral winding made of carbon fiber provided on the outside along the valley groove of the corrugated outer peripheral wall of the modified bond sheath body. The diameter of the spiral winding is defined as the diameter of the modified bond sheath body. And the depth of the valley groove.

[Action]

According to the above configuration, since the sheath body is made of resin, it does not rust even if it comes into contact with groundwater.

The peripheral wall of the sheath body is formed into a spiral corrugated shape, and a shape is devised to increase the binding force of cement paste or the like injected to fix the tension material inserted in the sheath body. However, since the resin has a small elastic coefficient in terms of material, the restraining force is still small.

However, a spiral winding made of carbon fiber is provided along the valley groove of the corrugated outer peripheral wall of the sheath main body. Since the carbon fiber has a large elastic coefficient in terms of material, the restraining force of the sheath body is compensated by providing the carbon fiber spiral winding along the valley groove of the corrugated outer peripheral wall in this manner. As a result, the above-mentioned restraint force becomes large as a whole, and it has good anchor strength.

The carbon fiber spiral winding does not rust even if it comes into contact with groundwater.

Therefore, the bond sheath of the anchor composed of the sheath body and the spiral winding made of carbon fiber has good corrosion resistance as a whole and has a long life.

〔Example〕

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

As shown in FIGS. 1 and 2, the bond sheath 20 of the anchor of the present invention comprises a sheath body 21 and a spiral winding 22.

The sheath body 21 is formed by forming a peripheral wall of a cylindrical body into a spiral waveform. Specifically, unevenness of a corrugation in the shape of peaks and valleys is sequentially formed in the longitudinal section of the peripheral wall, and this corrugation is set such that the undulations of the peaks and valleys are set to be relatively large, as is apparent from FIG. , And is formed in a spiral shape along the circumferential direction of the peripheral wall. That is, the sheath body 21 has the shape of a so-called odd-shaped bond sheath 10. The sheath body 21 is made of resin such as polyethylene.

Both ends of the sheath body 21 are open, or one end is open and the other end is closed.

On the outside of the corrugated peripheral wall of the sheath body 21, a spiral winding 22 is provided along the valley groove 21a.
The spiral winding 22 is made of carbon fiber.
The diameter D of the spiral winding 22 is determined by the diameter d of the sheath body 21, the depth of the valley groove 21a, a desired restraining force described later, and the like.

When the anchor is constructed by using the bond sheath 20 of the present invention having the above-described structure, it is performed 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. When one end of the bond sheath 20 is open and the other end is closed as described above, the closed end 20a is inserted deep inside the drilled hole 25. The bond sheath 20 has the spiral winding 22 made of carbon fiber attached to the sheath body 21 before being inserted into the drilled hole 25.

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 that constitutes the bond sheath 20 of the anchor of the present invention is formed of, for example, a resin such as polyethylene. The resin does not rust on contact with groundwater.

The restraining force F of the cement paste 28 or the like injected to fix the tension material 27 inserted in the sheath body 21 is
In the valley groove 21a outside the corrugated peripheral wall of the sheath body 21,
Since the spiral winding 22 made of carbon fiber is provided along this, the spiral winding 22 is supplemented and increased in size, and the adhesion strength thereof is increased.

This is because the peripheral wall of the sheath body 21 is formed in a spiral corrugation, and the carbon fiber material forming the spiral winding 22 has a large elastic coefficient.

Further, the carbon fiber forming the spiral winding 22 does not rust even if it comes into contact with groundwater.

Therefore, the bond sheath 20 of the anchor of the present invention composed of the sheath body 21 made of resin and the spiral winding 22 made of carbon fiber shows good corrosion resistance as a whole and has a long life. Will have.

[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 also has a large anchoring force of cement paste or the like injected to fix the tensile material and a good anchor strength. Shows excellent effects.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the bond sheath of the anchor of the present invention, FIG. 2 is a vertical sectional view of FIG. 1, and FIG. 3 is a longitudinal section showing an anchor construction state using the bond sheath of the anchor of the present invention. It is a side view. 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 ... Bond sheath of anchor; 21 ... Sheath body; 2
1a ... Valley groove; 22 ... Spiral winding.

Claims (1)

[Scope of utility model registration request] 1. A deformed bond sheath main body, which is made of a resin cylindrical body continuous with a straight unbonded sheath, and whose peripheral wall is formed in a corrugated shape having a large undulation, and a corrugated outer periphery of the deformed bond sheath main body. A spiral winding made of carbon fiber provided outside the groove along the wall, and the diameter of the spiral winding is related to the diameter of the modified bond sheath body and the depth of the groove. Anchor bond sheath characterized by being set in.