JPH0418085B2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to removable anchors.

<Prior Art> Conventionally, the following methods exist for removable anchors.

<A> A method in which heat-melting synthetic resin is placed around the tensile material, and when it is removed, the synthetic resin is melted using electric heat, etc., and the tensile material is removed.

<B> A method of filling a cavity prepared in advance in the anchor body with an expansion breaking agent to destroy the anchor body and remove the tensile material.

<C> A method in which a member that mechanically breaks under a load greater than a predetermined load, such as load-bearing mortar, is installed in the anchor body and the tension member is removed.

<Problems to be Solved by the Present Invention> The conventional anchor removal techniques described above have the following problems.

<B> Since anchors are driven deep underground, it is extremely difficult to cause frequent cracks in the anchor body and cause it to break as in conventional techniques.

Even if the anchor body can be destroyed, the problem remains that surrounding earth and sand will fall into the space created by the destruction of the anchor body, causing the ground above to sink.

<B> In general, the adhesion strength between the tensile material and the solidified material filled in the hole is very large, and a large load is required to separate the tensile material using tensile force as in the conventional technology. It may break and it may become impossible to remove the anchor body from the ground.

<C> Anchor boreholes are generally about 10 cm in length.
With conventional technology, it was extremely difficult to store the necessary anchor installation materials inside, as well as to provide the necessary space and equipment for removal. .

Therefore, if removal is absolutely necessary, a method is adopted in which the outer periphery of the anchor hole is bored with a diameter slightly larger than that of the existing anchor hole, and then the tensile material is removed (the so-called overcoring method).

However, this method requires a great deal of time and cost, and has been a major problem not only in anchor work but also in construction work as a whole.

<Objective of the present invention> An object of the present invention is to provide a removable anchor that allows tension members to be easily and reliably removed using a simple device.

<Configuration of the Present Invention> An embodiment of the present invention will be described below with reference to the drawings.

<A> Tensile material (Figures 1 and 2) The tensile material 1 uses a PC steel wire, etc., and when inserted into the drilled anchor hole 6, the deepest part is folded back to form a folded part 11. .

Then, the end portions 12 on the hole bottom side of a plurality of tensile members 1 formed in the same manner are connected by a gripping tool 2, which will be described later.

In this example, a case will be explained in which two tensile members 1 are connected.

<B> Gripping tool (Fig. 4) The gripping tool 2 connects two tensile members 1, and as in this embodiment, two grooves are provided in the block body, and the tensile members 1 are fitted into the grooves. There may be things that match.

In short, it is sufficient if the two tensile members 1 can be firmly connected.

<C> Hollow part (FIGS. 1 and 3) A hollow part 51 is provided by arranging the core tube 5 at the center of one group of tensile members, that is, at the axial center of the anchor body.

As will be described later, when the core tube 5 is attached to the guide tube 4, there is a thick cover portion 62 between the core tube 5 and the tensile member 1.
The tubular body has an outer diameter that is large enough to allow the solidifying material 61 to fall therein, and a hollow portion 51 having a sufficient space is provided inside the tubular body so that the peeled solidifying material 61 does not fall and become clogged.

Further, the core tube 5 should not be made of a member that is so thick and rigid that it becomes a resistance when the tensile material 1 is removed.

In other words, although it can withstand the injection pressure of the solidifying material 61,
The material and shape must be such that it does not become an obstacle when the tension member 1 is removed.

In this embodiment, a corrugated synthetic resin material will be considered.

By corrugating the core tube 5, it is possible to increase the surface area, increase the rigidity against pressure, and reduce the wall thickness.

Therefore, it does not become a resistance when removing the tensile material 1.

<D> Drawing material (Fig. 1) The drawing material 3 is a material strong enough to pull and remove the tensile material 1, such as a PC steel wire, and one end of it is attached to the upper end of the gripping tool 2. The free end is configured to pass through the hollow portion 51 and be exposed above the ground.

<E> Assembling each member (1) Attaching the gripper (Figures 2 and 4) Attach the gripper 2 to the end 12 of the tensile member 1 formed into a U-shape as described above.

(2) Attaching the guide tube and the drawn material (Fig. 2) The drawn material 3 is joined to the upper part of the grip 2 by welding or the like.

Next, the folded portion 11 is inserted into the guide tube 4 of the tubular body.

When inserting, the side surface of the folded portion 11 is held down with a simple compressor such as a vise.

For the guide tube 4, an SGP, a gas tube, etc. can be used, and a wire or tape may be directly wound around the folded portion 11 of the tensile material 1.

(3) Attaching the core tube (Figures 1 and 3) While introducing the drawing material 3 into the core tube 5, which has an outer diameter smaller than the inner diameter of the guide tube 4, insert one end of the core tube 5. Attach it to the extent that it is inserted lightly into the guide tube 4.

Next, the guide tube 4 is filled with a water stop material 41,
The guide tube 4 and the core tube 5 are completely tightly joined.

Therefore, the solidifying material 6 to be injected later into the core pipe 5 is
1 will not flow in and become an obstacle when the tensile material 1 is peeled off.

The water stop material 41 is made of a material softer than the solidifying material 61 so that the tensile material 1 can be easily removed.

For example, asphalt, a synthetic resin, a mixture of water glass and a hardening agent, etc. can be used.

<Operation of the present invention><A> Installation of anchor (FIG. 1) The removed anchor created as described above is inserted into the anchor hole 6 excavated in the ground.

At this time, since the core tube 5 is provided with a hollow portion 51, if buoyancy is generated by drilling water in the anchor hole 6 and insertion is difficult, water and synthetic A filler such as resin or granules is injected to ensure smooth insertion.

After inserting the anchor, insert the solidifying material 61 into the anchor hole 6.
Inject under pressure inside.

At this time, if the above-mentioned filler is injected into the core tube 5, the pressure at the time of injection of the solidifying material 61 causes the core tube to
is not deformed.

The solidifying material 61 is injected around the core tube 5 and the guide tube 4 to form a hollow portion 51 .

In addition, the tensile material 1 penetrates into the thick cover portion 62 and
It is also injected around the area.

Therefore, the solidifying material 61 is hardened in the thick cover portion 62, and a thin inner wall is formed.

This inner wall is formed to have a thickness that is easy to peel off when the tensile material 1 is removed, and is thick enough to provide sufficient proof stress of the anchor.

After hardening of the solidifying material 61, a predetermined tension is applied to the tensile material 1.
to complete the anchor installation.

<B> Removal of the anchor (Figure 5) After finishing using the anchor, remove the tension member 1 from underground.

First, the tension of the tensile material 1 is released, and the internally drawn material 3 is pulled using a jack or the like.

Then, since the folded part 11 is only filled with the soft water stop material 41 around the folded part 11, it can be easily pulled out upward.

When the drawn material 3 is further pulled upward, the tensile material 1 embedded in the solidified material 61 gradually destroys the thin inner wall of the solidified material 61 formed in the thick cover portion 62 and the core tube 5 from below. , and peels off from the solidifying material 61.

At this time, if a soft material is used for the core tube 5, the core tube 5 peels off from the solidifying material 61 so as to follow the tensile material 1 and turn up.

In this way, a kind of wedge effect is generated, making it easier for the tensile material 1 to peel off from the solidified material 61.

In the conventional anchor, since the hollow part 51 of the core tube 5 is not provided, the solidifying material 61 is injected into the entire anchor body, and the solidifying material 61 after hardening is injected into the entire anchor body.
A very large force was required to destroy the tensile material 1 and remove the tensile material 1.

However, by providing the hollow part 51 as in the present invention, the parts to be destroyed are only the thin inner wall part formed in the thick cover part 62 and the core tube 5, so the tensile material 1 can be easily removed. Now I can do it.

Further, a sufficient space is provided inside the core tube 5 so that the broken thin wall does not fall down and become clogged and become an obstacle to pulling out the tensile material 1 upward.

Then, by pulling the pulling material 3 upward, the tensile material 1 is peeled off over the entire anchoring length of the anchor filled with the solidifying material 61, and then the tensile material 1 is directly pulled and stretched. The tension member 1 is completely removed from underground, and the anchor removal work is completed.

<Other Examples> (Figure 6) The above example is a case in which two tensile members 1 are connected by a gripper 2, but as shown in Figure 6, the tensile members 1 are folded back and then extended as they are. The tensile material 1 can be used in place of the drawn material 3 by exposing it above the ground.

<Effects of the Present Invention> Since the present invention has been described above, the following effects can be expected.

<B> Conventional anchors do not have a hollow part inside the anchor body, so a solidifying material is injected into the entire anchor body, and after hardening, the solidifying material is destroyed and the tensile material is removed. required a great deal of force.

However, in the present invention, a core tube is installed within the anchor body to provide a hollow space.

Therefore, the only parts to be destroyed are the core tube made of a thin member such as a synthetic resin, and the thin inner wall portion formed between the core tube and the thick cover of the tensile material.

By pulling the pull-out material attached to the folded portion of the tensile material, a type of wedge effect was generated, and the tensile material was successfully peeled off easily from the solidified material.

Therefore, it has become possible to easily and reliably remove the anchor.

<B> The only parts that are destroyed when the tensile material is removed are a portion of the anchor body, that is, the core tube and the thin inner wall of the thick cover.

Therefore, even after the tension member is removed, the anchor body remains in the ground in its original shape.

Therefore, surrounding earth and sand will not fall into the space created when the anchor trunk is destroyed, and the ground above will not sink.

<C> Because the structure of the anchor device is simple,
Processing of the device can be done using input or a simple steel bending device such as a vise, allowing for flexible on-site processing.

<d> The structure of the anchor device is simple, so
Anchors can be installed at low cost,
Economic efficiency can be achieved.

[Brief explanation of drawings]

Fig. 1: An explanatory diagram of one embodiment of the apparatus of the present invention, Figs. 2 and 3: An explanatory diagram of the processing procedure for tensile material, Fig. 4:
An explanatory diagram of a gripping tool, FIG. 5: An explanatory diagram at the time of anchor removal, and FIG. 6: An explanatory diagram of another embodiment.

Claims (1)

[Scope of Claims] 1. An anchor that is installed by inserting a tensile material into a hole drilled in the ground, filling it with a solidifying material, and applying a predetermined tension to the tensile material after the solidifying material has hardened, the anchor comprising: In removable anchors that are removed after use, a hollow part is formed in the center of the tensile material group, each tensile member is folded back at its deepest part, and the tip of each tension member receives the tensile force out of the hole through the hollow part. A removable anchor characterized by being configured to give. 2. Connect the tips of each tensile material with a gripping tool, connect a pulling material placed inside the hollow part to this gripping tool, and apply a tensile force to the tip of the tensile material to the outside of the hole through this pulling material. A removable anchor according to claim 1, characterized in that it is configured to provide a removable anchor.