JP2909917B2 - Center core removal anchor method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a removal anchor method used for landscaping and various retaining wall works, and more particularly to a removal anchor method using a center core.

<Conventional Technology> There are various types of removal anchor methods, and a center core type removal anchor method is known as one of the methods.

This method will be described with reference to FIG. 3. As shown in FIG. 5, a resin having a special cross-sectional shape as shown in FIG. Center core b is disposed.

Further, a drawing PC steel material d for the purpose of removing the center core b is arranged over a range of the free length portion B which is covered with the sheath material c and is not in contact with the solidifying material a.

The center core b is coated with a lubricant on the surface to cover the core cover e.
Is housed.

Then, at the time of removal, the center core b shown in FIG. 6 is pulled out to form a hollow hole at the center.

Thereafter, as shown in FIG. 7, the tensioning PC steel material f is removed by applying a removing force to the tensioning PC steel material f to cut off from the consolidated material a.

<Problems to be solved by the present invention> In the above-described conventional removal anchor method, it may be difficult to remove the center core b for the following reasons.

That is, the larger the pressure of the consolidated material a acting on the sheath material c of the free length portion B, the more easily the sheath material c having a circular cross section is crushed. (See FIG. 4.) Therefore, the deformed portion of the sheath material c of the free length portion b makes it difficult for the center core b to pass.

PC for pulling out when forcibly pulling out center core b
Steel material d breaks or PC steel d for drawing is center core b
From the center core b.

If the center core b cannot be recovered, the anchor cannot be finally removed.

<Object of the present invention> The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a simple operation of a sheath material using a consolidated material without using a high-strength sheath material. It is an object of the present invention to provide a center core type removal anchor method capable of preventing deformation and smoothly extracting a center core.

<Means for Solving the Problems> That is, according to the present invention, the center core is arranged at the center of the anchor over the range of the anchoring length, and the tensioning PC steel material is arranged in the outer circumferential groove of the center core, and the free length is adjusted. Cover the tensioning PC steel with a sheath material over the area of the part to avoid contact with the consolidated material, apply a pulling force to the drawing PC steel connected to the center core, pull out the center core, and remove it to the center In the center core type removal anchor method of forming a hollow hole and applying a pulling force to the tensioning PC steel material and trimming and removing it from the consolidated material,
Before filling the anchoring material into the anchor hole, use an anchor in which a fluid for preventing deformation of the sheath material is sealed in a sheath material having a sealed structure in advance, and use the fluid at least until the bonding material hardens. It is characterized by being enclosed.

<Description of the Present Invention> Hereinafter, the present invention will be described with reference to the drawings.

<A> Structure of removal anchor FIG. 1 is a sectional view of the removal anchor used in the present invention.

1 is a center core disposed over the range of the fixing length portion A,
2 is a PC steel material for drawing fixed to the center of the center core 1,
3 is a PC steel material for tension housed in the outer circumferential groove of the center core 1,
Reference numeral 4 denotes a sheathing and / or tensioning PC steel material 2, a sheath material provided over the range of the free length portion B of the steel material 3, a sealing material 5 for sealing a boundary portion between the fixing length portion A and the free length portion B, and 6 a sheath material. 4 is a cap attached to the open end.

 The above configuration is the same as the conventional removal anchor.

However, in the removal anchor used in the present invention, the sheath material 4 provided in the area of the free length portion B has a sealed structure, and the fluid 7 is sealed in the sheath material 4 at the time of assembling the anchor or before filling the solidified material. Is different from the conventional removal anchor.

<B> Fluid to be sealed The fluid 7 to be sealed in the sheath 4 is for the purpose of resisting the pressure of the consolidated material and preventing deformation of the sheath material 4. A viscous member such as grease, a foaming material such as urethane foam, and a gas such as pressurized air can be used.

The method of enclosing the fluid 7 varies depending on the type of the fluid 7 to be used.

A fluid inlet may be opened in a part of the cap 6 for preventing leakage of the fluid 7, and the fluid 7 may be injected using the inlet.

Further, when the fluid 7 is not a gas, it is not necessary to seal the fluid 7 in a pressurized state for the purpose of use, and it is sufficient if the fluid 7 is sealed in a state that can resist the pressure of the consolidated material.

<Construction method> Next, a construction method of the removal anchor will be described.

<A> Anchor fixing method As shown in FIG. 1, the fluid 7 is sealed in the sheath material 4 to assemble the anchor.

 This anchor is inserted into the anchor hole 8.

Next, the entire area inside the anchor hole 8 is filled with a solidifying material 9 such as mortar.

Alternatively, the anchor may be inserted into the anchor hole 8 in which the entire region is filled with the solidifying material 9 such as mortar while the fluid 7 is injected into the sheath material 4.

When the anchor is set in the anchor hole 8, the consolidation material 9
Pressure acts to crush the sheath material 4.

However, the fluid 7 sealed in the sheath member 4 opposes this pressure and prevents the deformation of the sheath member 4 to maintain a circular cross section.

That is, since the difference in specific gravity between the inside and the outside of the sheath material 4 becomes small, the external pressure acting on the sheath material 4 becomes small.

After the solidifying material 9 is cured, the fluid 7 in the sheath material 4 is discharged, and then the fixing is performed using a fixing device and a tensioning device similar to those in the related art.

Of course, the anchor may be fixed while the fluid 7 is sealed.

<B> Removal method When removing the anchor, a removal force is applied to the drawing PC steel material 2 to remove the center core 1 located at the fixing length portion A.

Since the sheath member 4 has a circular cross section over the range of the free length portion B, the center core 1 can be smoothly extracted.

Lastly, it is the same as the conventional method that the tensioning PC steel 3 is cut off from the consolidated material 9 by applying a pulling force to the tensioning PC steel 3.

<Effects of the Present Invention> The present invention is as described above, and the following effects can be obtained.

<A> Until at least until the consolidated material is hardened, the sheath material in the free length portion can be prevented from being deformed only by sealing the fluid in the sheath material.

Therefore, the center core can be smoothly extracted.

<B> Conventionally, since the sheath material is crushed before the consolidated material hardens, the design length of the free length portion has been limited.

In the present invention, since the external pressure acting on the sheath material is reduced by the presence of the fluid, an anchor having a long free length can be designed.

<C> The fluid is not only used to prevent the sheath material from
Also exhibits the rust prevention function of steel materials.

[Brief description of the drawings]

FIG. 1: Explanatory drawing of the removal anchor method of the present invention, and a cross-sectional view of the anchor with a part omitted when the anchor is inserted FIG. 2: A cross-sectional view of the anchor with a part omitted after filling with the binder Fig. 3: Illustration of conventional removal anchor Fig. 4: Cross-sectional view of IV-IV in Fig. 3 Fig. 5: Cross-sectional view of fixing length part during fixing Fig. 6: Fixing length after removal of center core Fig. 7: Cross-sectional view of the fixing length at the time of pulling out the PC steel for tension

Claims (1)

(57) [Claims] 1. A center core is arranged at the center of an anchor over a range of a fixing length, and tension is applied to an outer peripheral groove of the center core.
Along with placing the PC steel material, covering the tensioning PC steel material with a sheath material over the free length area to avoid contact with the consolidated material, apply a pulling force to the drawing PC steel connected to the center core In the center core type removal anchor method, which removes the center core and forms a hollow hole in the center, applies a pulling force to the tensioning PC steel and trims and removes it from the consolidated material, the consolidated material is inserted into the anchor hole. Before filling, an anchor in which a fluid for preventing deformation of the sheath material is sealed in a sheath material having a sealed structure in advance is used, and the fluid is sealed at least until the consolidated material is hardened. The center core removal anchor method.