JP2759676B2 - Anchor construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for installing an anchor.

<Conventional technology> Anchors may be corroded by the influence of groundwater or the like.

In order to prevent the occurrence of such a phenomenon, standards for providing double protection (double protection) have been established by the Japan Society of Geotechnical Engineers, and have become mandatory in design and construction.

In that case, it is not always necessary to apply the sheath twice,
A cement paste having a tensile strength of a certain value or more (about 20 kg / cm ² or more) can also be counted as one of the protective materials.

However, injecting a cement paste having a high tensile strength requires high reliability in construction, which is actually a difficult task.

<Object of the present invention> The present invention has been made to solve such a problem, and provides a method of constructing a double-protected anchor with high reliability by a simple structure and construction. The purpose is to do.

<Configuration of the Present Invention> Next, an embodiment of the present invention will be described.

<A> The inner capsule 1 is a fixing portion of the anchor, and is exposed from the free length portion 2.

The outer periphery of the fixing unit 1 is covered with an inner capsule 3.

The inner capsule 3 is a bag-like container having only one end open.

In particular, the inner capsule 3 is made of a material that does not allow water to permeate.

 For example, the following materials are used.

Synthetic resin such as polyethylene, polypropylene, vinyl chloride, metal, cloth, etc.

The open end of the inner capsule 3 is attached to the boundary between the fixing section 1 and the free length section 2 by performing a sufficient water stopping process.

One end of the injection pipe is opened inside the inner capsule 3 so that injection from the outside to the inside of the inner capsule 3 is possible.

<B> Outer Capsule The outer side of the inner capsule 3 is further surrounded and covered by the outer capsule 4.

The outer capsule 4 is also a bag-shaped container with only one end opened.

However, the outer capsule 4 is made of a material having high permeability of water but low permeability of cement particles. In addition, the cement particles permeated to the outside of the outer capsule 4 can enhance the adhesive force with the wall surface of the anchor hole.

 For example, the following materials are used.

 Synthetic resin, cloth, etc.

The open end of the outer capsule 4 is
In a state surrounding the fixing portion 1 and the free length portion 2, the boundary between the fixing portion 1 and the free length portion 2 is subjected to a sufficient water stopping process and attached.

Therefore, the anchoring portion 1 of the anchor is
, And will be doubly surrounded by the outer capsule 4.

One end of the injection pipe is also opened inside the outer capsule 4 so that injection from the outside to the inside of the outer capsule 4 is possible.

<C> Other Embodiments The structure in which the inner capsule 3 and the outer capsule 4 are attached to the boundary between the fixing portion 1 and the free length portion 2 by performing a sufficient water stopping process has been described.

However, not only the anchoring part 1 of the anchor but also the free length part 2
Up to this point, a structure in which the inner capsule 3 and the outer capsule 4 double surround the inner capsule 3 may be adopted.

<Construction method> Next, a construction method will be described.

<A> Manufacture of anchor body The anchor body is double-coated with the inner capsule 3 and the outer capsule 4 to manufacture the anchor body.

<B> Drilling and Inserting The drill is drilled by a conventionally known method, and the manufactured anchor body is inserted into the inside.

<C> Injection of fixing material into inner capsule First, a fixing material 5 such as mortar or cement paste is injected into the inner capsule 3.

Since the inner capsule 3 is made of an impermeable material through which liquid does not pass, injection is completed when the inner capsule 3 is filled in an amount corresponding to the inner space.

<D> Injection of fixing material into outer capsule Next, the fixing material 5 is injected into the outer capsule 4.

Then, the outer capsule 4 expands to the extent that the outer capsule 4 comes into close contact with the inner wall of the hole.

Since the outer capsule 4 is made of a material having high permeability of moisture but low permeability of cement particles, if the injection is further continued at an appropriate pressure, the moisture of the fixing material 5 is squeezed to the outside, and the pores are reduced. Drained to the wall side.

Therefore, the concentration of the fixing material 5 inside the outer capsule 4 is increased, and a fixing material having a large tensile strength is obtained. Even if there are many cracks in the hole wall, the fixing material 5 does not escape from there. Thus, the fixing can be surely achieved.

Furthermore, since cement particles do not necessarily pass through the outside of the outer capsule 4 at all, it is possible to increase the adhesive force with the pore wall surface by the permeated cement particles.

<Effects of the present invention> Since the present invention employs the above-described construction method, the following effects can be obtained.

<B> Double protection of anchor body (double protection), which is required as an anchor standard of the Japan Society of Geotechnical Engineers
Can be easily performed.

Groundwater does not reach the steel wire because it is double protected.

Therefore, there is no danger of rust, and a highly reliable anchor can be installed.

<B> The outer capsule is made of a material having high moisture permeability but low cement particle permeability.

Therefore, it is possible to squeeze out the moisture of the fixing material to be injected, and to fill the material with a high fluidity during the injection and a material having a high concentration after the injection.

As a result, a fixing material having high tensile strength can be obtained, and the occurrence of cracks can be prevented with high reliability together with the inner and outer capsules.

<C> Since the outer capsule is located outside, even on the ground with many cracks, the fixing material can be prevented from flowing out and the fixing can be reliably performed.

<D> Only the portion surrounded by the outer capsule can be injected, and a high-quality fixing material can be injected into a limited portion.

<E> In addition to the grout's adhesive strength, the capsule can be expected to adhere to the tensile force of the anchor,
An anchor with a large tensile strength can be constructed.

[Brief description of the drawings]

 Fig. 1: Illustration of anchor body Fig. 2: Illustration of construction state

Claims (1)

(57) [Claims] At least a fixing portion of a fixing member of an anchor is covered with an impermeable capsule, and an outer periphery thereof is covered with a permeable capsule having high moisture permeability but low cement particle permeability, A fixing material is injected into the inside of the impermeable capsule and the inside of the permeable capsule, and the moisture of the fixing material is squeezed out of the permeable capsule to increase the concentration of the fixing material. A method for constructing an anchor, characterized in that cement particles permeated to the outside of the capsule enhance the adhesion to the wall surface of the anchor hole.