JPH0696846B2 - Anchor construction method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an anchor construction method, and more particularly to an anchor construction method capable of eliminating obstacles to the introduction of prestress force in the free length portion of the tension member. It is a thing.

(Prior Art) Conventionally, an anchor as shown in FIG. 4 has been used.
That is, a plurality of tension members b are arranged in a deformed sheath a whose length is integrated, and further two injection pipes c and d are arranged. One injection pipe c opens in the deformed sheath a, and the other pipe d opens in the deformed sheath a.

The hardening material e is injected from both of the injection pipes c and d to fill the entire length inside and outside the deformed sheath a with the hardening material e to be hardened.

(Problems to be Solved by the Invention) The above-described conventional techniques have the following problems.

<A> Since the hardened material e fills the entire length of the deformed sheath a and hardens, the hardened material e hardens on the outer periphery of the tension material b regardless of the free length portion and the fixing portion of the tension material b. . The free length portion of the tensile member b is inserted into the unbonded sheath f to ensure the free elongation of the tensile member b. However, if the unbonded sheath f is twisted or bent, the surroundings of the unbonded sheath f may be deformed. The hardened material e hardens. Even if a prestressing force is applied to the tensile member b, friction may occur between the tensile member b and the unbonded sheath f, and the prestressing force as designed may not be introduced.

<B> A polyethylene sheath or the like is used as the deformed sheath a, but the sheath a of the same material covers the outer circumference regardless of the free length portion and the fixing portion of the tension member b. Therefore, the strength of the fixing part, which requires strength, is not sufficient, and if the upper part of the free length is particularly corrosive, the conventional thin polyethylene sheath is not sufficient, and either way is insufficient, and halfway measures are taken. Often becomes.

<C> Another problem that the deformed sheath a is a synthetic resin such as polyethylene is the problem of rigidity. If the synthetic resin is used, the rigidity is low, and the hardened material e is applied in the sheath a by applying pressure.
When you inject, it may lose the injection pressure and explode. Further, the synthetic resin is soft to restrain the hardened material e inside, and the force to restrain the hardened material e is small.
As a result, if a load is applied and the adhesion between the tensile material b and the hardened material e is broken, the adhesion proof strength will be drastically reduced.

<D> The deformed sheath a and the injection pipe c are fixed by the water blocking material g at the innermost portion of the deformed sheath a. The position may shift and the anchor may not work as designed.

The present invention has been made to solve the above problems, does not hinder the introduction of prestressing force, is economical by using an appropriate sheath, and is a method of implementing an anchor having a large anchoring force. The purpose is to provide.

(Means for Solving the Problem) In the anchor construction method according to the present invention, the free length part sheath and the fixing part sheath are continuously arranged in the drilled hole. A polyethylene sheath is used as the free length sheath, and a steel deformed sheath is used as the anchor sheath.

The tensile material inserted in the unbonded sheath is exposed in the polyethylene sheath. A waterproof material is filled in the joint between the polyethylene sheath and the steel deformed sheath. As a result, the tension member and the steel deformed sheath can be integrated. The inside and outside of the steel deformed sheath is filled with a hardening material and hardened.

The polyethylene sheath may be filled with grease or may be hollow.

The filling pipe inserted into the drilled hole from the surface of the earth is brought near the innermost part of the steel deformed sheath. Similarly, the air vent pipe inserted from the ground surface into the drilled hole is opened in the vicinity of the water blocking material in the steel deformed sheath. The hardening pipe is filled from the filling pipe, and the air in the steel deformed sheath is discharged from the air vent hole.

(Function) No hardening material is injected into the polyethylene sheath. Therefore, the unbonded sheath that covers the tension member in the free length portion bends freely and friction with the tension member does not occur.

The steel deformed sheath has high rigidity. Therefore, even if the hardening material is injected at a high pressure, the sheath does not burst due to the pressure. In addition, the hardened material inside is restrained with high rigidity, and even if the adhesion breakage occurs, the hardened material restrains the tensile material and suppresses a decrease in adhesion proof strength.

By arranging the air vent pipe, the hardened material is filled in the deformed steel sheath, and no cavity is formed. Further, it is possible to know that the hardening material is filled in the fixing unit sheath by returning the hardening material to the ground surface through the air vent pipe.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

In the figure, 1 is a polyethylene sheath which is a free length sheath, and 2 is a deformed steel sheath which is a fixing part sheath and is made of steel and has irregularities formed around it. The polyethylene sheath 1 and the steel deformed sheath 2 are continuously arranged in the drilled hole 3.

A plurality of tensile members 4 are arranged in the polyethylene sheath 1 and the steel deformed sheath 2. The tensile members 4 are inserted in the unbonded sheath 5 in the polyethylene sheath 1 and exposed in the steel deformed sheath 2. I'll do it. As the tensile member 4, a stranded steel wire, a steel wire or the like can be used.

Inside the polyethylene sheath 1 and the steel deformed sheath 2, a filling pipe 6 and an air vent pipe 7 are arranged from the surface of the earth, and the filling pipe 6 reaches the vicinity of the innermost portion of the steel deformed sheath 2.

A water blocking material 8 is filled in the connecting portion between the polyethylene sheath 1 and the steel deformed sheath 2. Blown asphalt or epoxy resin can be used as the water blocking material 8. The water blocking material 8 fixes and integrates the tension material 4 and the sheaths 1 and 2. Therefore, the positional relationship between the tensile member 4 and the sheaths 1 and 2 will not be displaced in the subsequent work. At this time, the air vent pipe 7 is arranged in the fixing unit sheath 2 so as to open near the water blocking member 8.

In the state as described above, the hardening material 9 such as cement grout is filled through the filling pipe 6. The injection pressure is increased to sufficiently fill the interior of the drilled hole 3 with the hardened material 9, but since the sheath 2 is made of steel and has high rigidity, the sheath 2 does not burst due to the pressure. The hardened material 9 fills the inside and outside of the steel deformed sheath 2. Air and water in the steel deformed sheath 2 are discharged through the air vent pipe 7.

By further filling the hardening material 9, the hardening material 9 fills the outer circumference of the polyethylene sheath 1 and the air vent pipe 7. It is possible to know that the fixing material sheath 2 is filled with the hardening material 9 by blowing out the hardening material 9 from the air vent pipe 7. The polyethylene sheath 1 may not be filled with the hardening material 9 and may be a hollow, or may be filled with grease.

When the prestress is introduced into such an anchor, the hardening material 9 is not filled in the polyethylene sheath 1, friction does not act on the tensile member 4, and the prestress force as designed can be introduced. it can.

Even if the load acts to break the adhesion between the tensile material 4 and the hardened material 9 in the fixing portion, the steel sheath 2 having high rigidity firmly restrains the hardened material 9. The constrained hardening material 9 strongly constrains the tensile material further to prevent a large decrease in the adhesion strength.

(Effects of the Invention) Since the present invention has the configuration as described above, the following effects can be obtained.

<a> Since the polyethylene sheath is not filled with a hardening material, friction does not occur between the tensile material and the unbonded sheath,
It is possible to introduce a prestress force as designed.

<B> Since the tension material and the fixing portion sheath are integrated by the hardening material of the water blocking portion, the problem of the conventional construction method that the tension material and the sheath are displaced during the insertion work of the anchor into the drilled hole was solved.

<C> By adopting a polyethylene sheath as the free length part sheath and a steel deformed sheath as the fixing part sheath, the sheath can be appropriately used for fixing the anchor and introducing the prestress force. That is, although the steel sheath is expensive, it can be made inexpensive by using it only for the fixing portion.

<D> Since the deformed sheath made of steel having high rigidity is adopted as the fixing sheath, the sheath does not burst even when the hardening material is injected under high pressure.

<E> Since the deformed sheath made of steel with high rigidity is used, even if the hardened material and the tensile material are no longer attached, the hardened material is restrained by the restraining force of the deformed sheath, and the hardened material restrains the tensile material. , Obtains adhesion strength (residual strength) close to that of adhesion. Therefore, the adhesive strength does not decrease sharply.

<F> By using the filling pipe and the air vent pipe, the hardening material can be filled only in the fixing portion sheath. Further, it is possible to confirm that the hardening material is filled in the fixing portion by the air vent pipe exposed on the surface of the earth.

[Brief description of drawings]

1 and 2 are sectional views of an embodiment of the anchor according to the present invention, FIG. 3 is an overall view of the anchor, and FIG. 4 is a sectional view of a conventional example. 1 ... polyethylene sheath, 2 ... steel deformed sheath, 3
...... Drilling, 4 ... Tensile material, 5 ... Unbonded sheath, 6
…… Filling pipe, 7 …… Air vent pipe, 8 …… Water blocking material, 9 …… Hardening material.

Claims (1)

[Claims] 1. A polyethylene sheath having a free length and a steel deformed sheath having a fixing length are continuously arranged in a hole, and a tension member inserted in an unbonded sheath is arranged in the polyethylene sheath to make a steel. In the deformed sheath, the tension material is exposed, and the waterproof material is filled in the joint between the polyethylene sheath and the steel deformed sheath to fix and integrate the tension material and the steel deformed sheath. The air vent pipe that was brought near the innermost part of the steel deformed sheath and was also inserted into the drilled hole from the ground surface was opened near the water stop material in the steel deformed sheath, and the hardening pipe was filled from the filling pipe. An anchor construction method in which the air inside the steel deformed sheath is discharged from the air vent holes.