JPH10152836A - Packer for grround anchor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the strength of a packer part so that breakage cannot be caused, and also to reduce the diameter of a drilling hole, and to properly infiltrate grout material into the surrounding ground. SOLUTION: In a packer for a ground anchor, a steel packer sheath is connected so as to be adjacent to a fixed length part sheath. Then, a packer member 8 such as cloth is fitted to the outside of the packer sheath to form a bag- shaped space. The end of a packer injection pipe 11 is bent to be connected to the side opening to communicate with the bag-shaped space, and the end of an outer pipe 12 is also bent to be connected to the opening that is situated to the side of the packer sheath and to the fixed length part side than the packer member 8. Since the outer pipe 12 is housed inside the packer sheath, the diameter of the anchor can be reduced, and also the diameter of the drilling hole can be reduced. Since the packer sheath is made of steel, even if the pipes 11, 12 are connected to the packer sheath from the inside, the occurrence of cracks can be prevented. Further, since the sheath is made of steel, grout material 7 can be injected at a large pressure, and also it can be injected into the fixed length part at a large pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground anchor which is fixed by being inserted into a hole in a ground, and more particularly to a case where grout material is injected under pressure into the ground around the ground anchor to increase the anchoring strength. The present invention relates to a packer for sealing a grout material in a drilled hole and reliably injecting the grout material into the ground.

[0002]

2. Description of the Related Art A ground anchor has been developed in which a plurality of tension members are bundled, passed through a sheath, inserted into a hole formed in the ground, and grout is injected into the hole and fixed. I have. In this ground anchor, the strength of the ground around the drilled hole is a condition for increasing the strength of the ground anchor. The anchor is attached to the ground around the drilled hole by the injected grout material, and if the surrounding ground is brittle, the anchor cannot be firmly fixed in the ground.

[0003] For this purpose, means has been adopted in which a pressurized grout material is penetrated so as to be pressed into the surrounding ground, and the surrounding ground is strengthened by the grout material to increase the anchoring force of the anchor. In order to infiltrate the grout material into the surrounding ground by pressurizing the inside of the drill hole, a means for sealing the grout material so that the grout material does not blow out from the drill hole opening must be adopted. A packer is used as a means for this containment. As a packer, a bag-like material is used that injects grout material into the drilled hole and inflates it.The packer is inflated between the anchor and the surrounding ground, and the grout material is injected under the pressure. And penetrate the surrounding ground.

[0004]

The above-mentioned packer is mounted around an anchor and swelled in one of the drilled holes. When the packer is arranged near the opening of the drilled hole, the soft ground around the opening is formed. In some cases, it may not be able to seal the drill hole sufficiently. On the other hand, it is preferable to arrange the packer deep in the hole, for example, near the anchoring length of the anchor, and to inflate it in a hard rock part. However, since the hole is deep in the hole, the state of the packer cannot be confirmed. Since the high pressure grout material is sealed by the packer, the grout material sealed in the packer itself needs to be high pressure. If the rigidity of the inner sheath for attaching the packer to the outer periphery is insufficient, the high pressure grouting material may cause the packer sheath to be crushed inward and damage the inside of the anchor. It is necessary that the rigidity of the packer portion is sufficient to dispose the packer at a position where it cannot be confirmed.

[0005] The pipe for injecting the grout material into the ground around the fixing length portion is called an outer pipe, and this outer pipe has conventionally been inserted into the borehole through the outside of the ground anchor. That is, the outer pipe was located inside the borehole outside the diameter of the anchor, which means that the outer pipe protruded outside the anchor having a circular cross section. With such a configuration, the diameter of the drill hole must be increased accordingly, and increasing the diameter of the drill hole leads to a large increase in construction cost, and the space where the outer pipe protrudes is wasted. Dead space. In order to solve such problems, it is conceivable to arrange the outer pipe inside the anchor sheath to make the diameter of the anchor as small as possible.However, it is a major problem how to open the outer pipe arranged inside to the outside. Becomes It is very difficult to connect the outer pipe by making a hole in a sheath made of a synthetic resin or the like, since cracks or the like may be generated when processing is performed. The problem with this connection was the same for a packer filling pipe that passes inside the packer.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a packer of a ground anchor which has high strength and high reliability and which does not cause damage during processing. The purpose is to:

[0007]

A ground anchor packer according to the present invention solves the above-mentioned problems by using a steel sheath as the packer sheath disposed inside the packer material.

[0008]

In the present invention, a portion of the free length sheath of the ground anchor adjacent to the anchoring length portion is formed as a steel packer sheath and is continuous with the anchoring length sheath. A packer material is arranged in a bag shape so as to cover the outside of the packer sheath. The bag shape means that the packer material is arranged outside the packer sheath, the front and rear openings are closed, and a bag-shaped space is provided between the packer material and the packer sheath. A high-strength cloth material made of synthetic resin can be used as the packer material.

[0009] The packer injection pipe, which has been passed through the free length sheath and led to the packer sheath, has its tip bent and connected to the opening on the side of the packer sheath to form a space formed by the packer material and the packer sheath. To communicate with
Similarly, the outer pipe housed in the packer sheath passed through the free length sheath is bent at the tip and connected to the opening on the side of the packer sheath, and is connected to the outside of the ground anchor at the fixed length side than the packer material. Communicate.

Since the packer sheath is made of steel, it has a high strength. Even if a high-pressure grout material is injected into the space between the packer material and the packer sheath, it is not crushed and has high reliability. Since the packer sheath is made of steel, it does not crack even if an opening is formed in the packer sheath to connect the pipes.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the drawings. In the figure, reference numeral 1 denotes an anchor tension member such as a PC strand, which is bundled together with an inner exhaust hose 2, an outer exhaust hose 3, and an inner injection hose 4. The fixing length side of the tensile member 1 is passed through a modified fixing length sheath 5 made of steel and having irregularities around the periphery. A tubular packer sheath 6 is connected adjacent to the fixing length sheath 5. The connection with the packer sheath 6 is performed by screwing a joint collar 7 having a thread on the outer periphery provided at the end of the packer sheath 6 into the inside of the fixing long sheath 5. The packer sheath 6 is made of steel, and a tubular cloth material 8 is disposed around the packer sheath 6. The front and rear ends of the packer material 8 are sandwiched between the heat-shrinkable tube 9 and the packer sheath 6. It is fixed by a steel band 10. Thereby, a bag-shaped space is formed between the packer material 8 and the packer sheath 6.

A packer injection pipe 11 and an outer pipe 12 are both housed inside the packer sheath 6, and the tip of the packer injection pipe 11 is curved and connected to a side opening of the packer sheath 6 by welding to form a packer material. 8
And a space between the packer sheath 6. The packer injection pipe 11 is provided with a check valve 19. The outer pipe 12 has a curved end and is connected to the opening on the side of the packer sheath 6 by welding, and communicates with the outside of the sheath 6 on the fixing length side of the packer material 8. Adjacent to the packer sheath 6, a free-length sheath 12 made of a synthetic resin is connected thereto.
Both 1 and the outer pipe 12 pass through the free-length sheath 12 and protrude from the end of the free-length sheath 12. The inside of the packer sheath 6 is filled with a waterproof material 14 such as grease from a waterproof material inlet 13. Both ends inside the packer sheath 6 are sealed with urethane seal tapes 20.

Next, a description will be given of an embodiment in which an anchor is installed upward in a tunnel using the above ground anchor. A drilling hole 16 is excavated on the ground by a drilling machine 15. (FIG. 5) A ground anchor is inserted into the hole 16, a hole-in anchor is driven around the opening of the hole 16, and an angle member 18 is attached to fix the ground anchor. At this time, the position of the packer material 8 must be located on a stable high-quality ground around the hole 16. The grout material 17a is injected into the fixing long sheath 5 using the inner injection hose 4. When the grout material 17a comes out of the inner exhaust hose 2, it is confirmed that the grout material 17b is filled in the fixing long portion sheath 5. Next, using the packer injection pipe 11,
Grout material 17b is injected under pressure. (FIG. 6) The packer material 8 swells in the hole 16 and seals the gap between the hole 16 and the surrounding ground.

A grout material 17 c is injected between the fixing long sheath 5 and the ground 16 using the outer pipe 12. (FIG. 7) The grout material 17c is injected at a considerably high pressure, and penetrates into the ground around the borehole 16. The fact that the grout material 17c is filled by the discharge of the grout material 17c from the outer exhaust hose 3 is known, and the grout material 17c permeates into the ground by being further pressurized and injected. Therefore, injection is performed at a considerably high pressure into the inside of the packer material 8 and the fixing length portion side. However, since the packer sheath 6 is made of steel,
The sheath 6 is not deformed by pressure. Grout 17
After hardening, the tension member 1 is tensioned and fixed. (FIG. 8)

[0015]

The present invention has the above-described configuration, and can obtain the following effects. Since the packer sheath used was made of steel and had high strength, the sheath was not crushed by pressure, the packer material could be expanded by large pressure, and the inside of the drilled hole could be reliably sealed. Since the outer pipe is housed in the packer sheath, the diameter of the anchor can be made as small as possible, dead space in the drill hole does not occur, the diameter of the drill hole itself can be reduced, and the construction cost can be reduced. Can be. Since the packer material is made of steel, open a hole in this,
Even if the tip of the inner outer pipe or packer injection pipe is curved and connected, the sheath does not crack, so the outer pipe can be stored inside the sheath and the diameter of the anchor itself can be reduced as described above It became. The outer pipe was housed in a steel packer sheath and connected to the opening on the anchoring length side of the sheath, and the packer injection pipe was also connected from the inside to the side opening of the packer sheath. Therefore, the packer sheath, the outer pipe and the packer injection pipe can be integrally formed at the factory, and the anchor becomes highly reliable. Since the inner sheath of the packer is made of steel and has high strength, the grout material can be injected into the packer by a large pressure, so that the anchor can be securely fixed in the hole. Since the packer seals the inside of the drilling hole with a large pressure, grout injection on the fixing length side can be injected at a high pressure, and the grout material can be well penetrated into the ground to strengthen the surrounding ground and improve anchor anchoring power. It can be greatly stabilized. Since the packer is provided adjacent to the fixing length portion, the packer is located in the high-quality ground at the back of the ground, so that the ground does not collapse even when pressure is applied, and the drilled hole can be reliably sealed. Since the inside of the hole is sealed by the packer, the grout material or the like does not fall and is extremely suitable for an upward anchor or the like. Since the packer is located near the fixing length, the work can be performed with the minimum necessary grout material.

[Brief description of the drawings]

FIG. 1 is a sectional view of a packer portion.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along line CC of FIG. 1;

FIG. 5 is a sectional view of a drilling operation.

FIG. 6 is a sectional view of grout material injection into a packer.

FIG. 7 is a cross-sectional view of grouting material injection outside the fixing length portion.

FIG. 8 is a sectional view of anchor anchoring.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tensile material 2 Inner exhaust hose 3 Outer exhaust hose 4 Inner injection hose 5 Fixing long sheath 6 Packer sheath 7 Joint collar 8 Packer material 9 Heat shrink tube 10 Steel band 11 Packer injection pipe 12 Outer pipe 13 Waterproof material inlet 14 Water stoppage material 15 Drilling machine 16 Drilling hole 17 Grout material 18 Angle material

Claims (1)

[Claims] A grout material injection pipe is bundled together with a plurality of tension members, and is located on a ground anchor disposed between the fixing long sheath and the free long portion, and is adjacent to the fixing long sheath among the free long sheaths. The part is a packer sheath made of steel, a packer material is arranged in a bag shape so as to cover the outside of this packer sheath, and the packer injection pipe stored in the sheath is bent at the tip and connected to the opening on the side of the packer sheath. To communicate with the space between the packer material and the packer sheath,
An outer pipe also housed in the sheath is a ground anchor packer that bends its tip and connects to the side opening of the packer sheath to communicate with the outside of the ground anchor on the fixing long side of the packer material.