JPH0714423Y2 - 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.

[Conventional technology]

Conventionally, when anchoring is performed 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.
Insert a tension member 3 made of PC steel stranded wire or the like. The tensile member 3 is covered with an unbonded sheath 4 such as a polyethylene hose so that only the tip 3a is exposed.

Next, 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, when the anchor is constructed 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, and the tensile member shown in the grout 5 is drawn. A lateral crack 6 in the direction orthogonal to 3 was generated.

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.

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, while the cement paste 8 or the grout 5 is injected into the bond sheath 7, the grout 5 is injected into the space inside the drilled hole 2 and hardened to remove the exposed tip portion 3a of the tensile member 3 and the bond sheath 7. Fix and fix.

Then, the tension member 3 was prestressed by tensioning the extension side with a jack or the like.

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.
The vertical cracks 9 and the lateral cracks 6a and 6b along the direction may occur, and these cracks reduced the compressive strength and adhesive strength of the anchor.

Therefore, as shown in FIG. 6, a so-called modified 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 cylindrical body whose peripheral wall is formed in a spiral corrugation, and there are mainly two types, that is, a metal type and a polyethylene type.

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

[Problems to be solved by the device]

By the way, when the anchor is constructed by using the two types of deformed bond sheaths 10 as described above, there are the following problems.

In the deformed bond sheath 10 made of metal, the cement paste 8 or the like has a strong binding force due to its high elastic modulus in terms of material.
Although the adhesion strength is large, there is a problem that the deformed bond sheath 10 itself is rusted due to contact with groundwater and becomes brittle and has a short life.

Contrary to the metallic one, the odd-shaped bond sheath 10 made of polyethylene 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 or the like 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-mentioned object, the anchor bond sheath of the present invention is made of a resin cylindrical body that is connected to a straight unbonded sheath and has both ends open, and its peripheral wall is spiral and has a large undulation. And a spiral spiral winding made of steel provided inside the deformed bond sheath body along the mountain groove of the corrugated outer peripheral wall of the deformed bond sheath body. The diameter of the spiral winding is set in relation to the diameter of the deformed bond sheath body and the depth of the valley groove so as to obtain a desired restraining force on the material.

[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 corrugated spiral shape, and a shape is devised to enhance the restraining force of the semmet 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 binding force is still small.

However, the spiral winding made of steel is provided along the mountain groove of the corrugated inner peripheral wall of the sheath body. Since steel has a large elastic coefficient in terms of material, the restraining force of the sheath body is supplemented by providing the steel spiral winding along the ridge groove of the corrugated inner peripheral wall in this way, and as a result, The above-mentioned restraint force becomes large as a whole and has good anchor strength.

The spiral winding is provided along the mountain groove of the corrugated inner peripheral wall of the sheath body. That is, since the spiral winding is located inside the sheath body, even if a lateral crack occurs around the sheath body and groundwater passes through the lateral crack, the groundwater is still contained in the sheath body. It is blocked by the peripheral wall of the sheath and does not penetrate into the inside thereof, and the steel spiral winding located in the sheath body does not rust.

As described above, the bond sheath of the anchor composed of the sheath body and the steel spiral winding located inside the sheath body 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. Concretely, unevenness of a ridge-valley corrugation is sequentially formed in the longitudinal section of the peripheral wall, and this corrugation is set such that the undulations of the ridges 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.

A spiral winding 22 is provided inside the corrugated peripheral wall of the sheath body 21 along the mountain groove 21a. The spiral winding 22 is made of steel. This spiral winding
The diameter D of 22 is determined by the diameter d of the sheath body 21, the depth of the groove 21a, and a desired restraining force F described later.

When an anchor is constructed using the bond sheath 20 of the present invention thus constructed, 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. As mentioned above, the bond sheath
When one end of 20 is open and the other end is closed, the closed end 20a is inserted deep inside the drilled hole 25.
The bond sheath 20 is, before being inserted into the drilled hole 25,
The steel spiral winding 22 is attached to the sheath body 21 in advance.

Next, the tip portion 27a of the tensile member 27 exposed from the unbonded sheath 26 is inserted into the bond sheath 20.

Then, while the cement paste 28 or the grout 29 is injected into the bond sheath 20, the grout 29 is injected into the space inside the drilled hole 25 and hardened to fix the exposed tip portion 27a of the tensile member 27 and the bond sheath 20. Fix it.

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

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 of the bond sheath 20 of the anchor of the present invention is applied to the mountain groove 21a inside the corrugated peripheral wall of the sheath body 21. Along this the steel spiral winding 22
Is provided to increase the adhesion strength.

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

Further, as described above, since the sheath body 21 is made of resin, it does not rust even if it comes into contact with groundwater.

The spiral winding 22 is located in the sheath body 21,
The sheath main body 21 is provided along the corrugated inner peripheral wall 21a.

By the way, a lateral crack may occur around the sheath body 21, and groundwater passes through the lateral crack. However, the groundwater is blocked by the peripheral wall of the sheath body 21 and does not enter the inside thereof.
The steel spiral winding 22 located inside does not rust.

As described above, the anchor bond sheath 20 constituted by the sheath body 21 and the steel spiral winding 22 positioned inside the sheath body 21 has good corrosion resistance as a whole and has a long life. Is.

In order to completely prevent the intrusion of groundwater into the sheath body 21 and to more reliably protect the steel spiral winding 22 from rust caused by groundwater, one end of the sheath body 21 is opened. It is desirable to use one that is closed at the other end.

[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 a bond sheath of an anchor of the present invention, FIG. 2 is a vertical cross-sectional view of FIG. 1, and FIG. 3 is a vertical 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 ... Anchor bond sheath; 21 ... Sheath body; 21a ... Mountain groove; 22 ... Spiral winding.

Claims (1)

[Scope of utility model registration request] 1. A deformed bond sheath main body, which is continuous with a straight unbonded sheath and is made of a resin cylindrical body whose both ends are open, and whose peripheral wall is formed in a corrugated shape with a large undulation. A spiral winding made of steel provided inside the profiled bond sheath main body along the corrugated outer peripheral wall of the profiled bond sheath main body is provided, and a desired restraining force is applied to the tensile member inserted into the profiled bond sheath main body. To obtain, the diameter of the spiral winding is set in relation to the diameter of the deformed bond sheath main body and the depth of the trough, and the bond sheath of the anchor is characterized.