JP2002088754A - Head-section anchorage structure of ground anchor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that water cutoff properties are improved as a curing pipe corresponding to the angle of drilling of an anchor hole regarding the anchorage structure of a head section in a ground anchor preventing the floating of the collapse of a ground slope such as the face of a slope, a retaining wall or the like and a wall surface. SOLUTION: In a head-section anchorage structure, in which the head section of the ground anchor is tensed and anchored, the cylindrical curing pipe 1, in which a rear section on the anchor hole side in the head section of the ground anchor is covered while a strand is inserted to a bottom plate section, has the head-section anchorage structure of the ground anchor, in which a flexible collar section 1d for cutoff is installed into a hole 1c for inserting the strand formed to the bottom plate section 1b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head anchoring structure in a ground anchor for preventing collapse of a slope or wall of a ground such as a slope or a retaining wall, falling of a building, and floating of a building.

[0002]

2. Description of the Related Art Conventionally, as a head anchoring structure of a ground anchor, as shown in FIGS. 5 and 6, an inner wall surface of a through-hole 21 of a pressure receiving plate 20 made of cast-in-place concrete frame, precast concrete or steel. An unbonded strand 23 made of a PC stranded wire having a front end fixed at the bottom of the anchor hole 32 and a rear end protruding above the ground surface is fitted with a reinforcing pipe or a penetration pipe (steel casing or void pipe) 22. Are provided in a required number, and the stiffening plate 24 is inserted into the opening of the reinforcing pipe 22 so that the stiffening plate 24 is
Then, the curing tube 25 is inserted into the through hole of the bottom of the curing tube 25 so that the strand 23 is inserted into the opening of the stiffening plate 24, and then the anchor plate 26 is mounted. It is known that the strand 23 is fixed after a required tension by a fixing nut 27 and an anchor head 28 (only an anchor head is used without using a fixing nut).

[0003] The anchor head 28 is further covered with a protective cap 29 for rust prevention, and rust-preventive oil is sealed inside. The protective cap 29 is covered with an outer cap 30. Thus, the pressure receiving plate 20
A rust-prevention treatment is applied to the rust generation of the strand 23 due to the infiltration of rainwater or the like from outside.

On the other hand, the curing pipe 25 is provided for preventing the strand 23 from rusting against intrusion of groundwater or the like from the ground 31 to the inside of the pressure receiving plate 20. To this end, the inside of the curing pipe 25 is filled with a rust preventive material 25b, and the bottom portion is formed of an elastic rubber cap 25a, and groundwater from the fitting portion between the insertion hole 25c of the rubber cap 25a and the strand 23 is formed. Etc. are prevented.

[0005]

However, when constructing the ground anchor, it is inevitable that the inclination angle of the slope C and the pressure receiving plate surface B or the angle of drilling the anchor hole 32 has a certain error. Things. In this case, since the angle of the anchor hole 32 with respect to the pressure receiving plate surface B has an error from the design angle, the strand is not parallel to the axis of the curing pipe, but is inclined / biased, and the rubber of the curing pipe is not slid. There is a risk that the rust preventive material 5b leaks out of engagement with the cap. In addition, there is a problem that the curing tube is forcibly bent by the strand unless the setting angle between the tensioned and fixed strand and the curing tube is set as set. The present invention has been proposed to solve such a problem.

[0006]

The gist of the present invention for solving the above problems of the ground anchor head fixing structure according to the present invention is to provide a head anchor structure for tensioning and fixing the head of a ground anchor. The tubular curing pipe that covers the back side of the anchor hole side of the head and the strand is inserted through the bottom plate has a flexible flange for stopping water in the strand insertion hole provided in the bottom plate. It is provided.

[0007] The gist of the ground anchor head fixing structure according to the present invention is to provide a head anchoring structure for tensioning and fixing the head of the ground anchor. The opening of the curing pipe is fitted and supported in a support hole of a stiffening plate placed on the pressure receiving plate, and the curing pipe is covered with the tubular curing pipe in which the strand is inserted through the bottom plate. Is provided with a flange portion sandwiched between the stiffening plate and the anchor plate.

Further, the outer peripheral portion of the opening of the curing tube supported by the support hole of the stiffening plate placed on the pressure receiving plate is formed to have a tapered portion which is made thicker on the outside. Including.

According to the head anchoring structure of the ground anchor according to the present invention, even if the angle at which the anchor hole is drilled with respect to the slope is different from the set angle, the flexible flange portion in the strand insertion hole can be formed. It follows and follows the inclined or deviated strand outer peripheral surface, so that the adhesion performance is maintained and the water stopping performance does not decrease.

[0010] The flange provided at the opening of the curing pipe is sandwiched between the stiffening plate and the anchor plate, and is strongly compressed by the tension of the strand to increase the adhesion and improve the water stopping performance. improves.

Further, by forming the tapered portion by making the outer peripheral portion at the opening of the curing tube a tapered surface, the root portion between the flange portion and the main body of the tubular body substantially perpendicular to the flange portion becomes thick. In addition, the strength of the anchor plate against the compressive force is increased to prevent the occurrence of cutting or the like. Further, the tapered surface of the curing pipe and the tapered surface of the auxiliary steel plate are brought into close contact with each other to improve the water stopping performance.

[0012]

Next, a head anchoring structure of a ground anchor according to the present invention will be described with reference to the drawings. To facilitate understanding of the present invention, portions corresponding to those of the conventional example will be denoted by the same reference numerals as those of the conventional example.

As shown in FIG. 1, the curing tube 1 used in the head anchoring structure of the ground anchor according to the present invention includes a cylindrical main body 1a and a bottom plate 1b formed at one end. It is formed integrally.

The curing tube 1 is formed of an elastic material such as synthetic or natural rubber or synthetic resin (for example, chloroprene rubber, soft epoxy resin, etc.). The bottom plate portion 1b is provided with a required number of strand insertion holes 1c corresponding to the arrangement of the pressure receiving plate through-holes 21 and the strands 23 provided in the reinforcing pipe 22. This strand insertion hole 1c
Is slightly smaller than the outer dimension of the strand 23. Further, as shown in FIG. 1, the insertion hole 1c has a slight taper 1h so that it can be easily removed at the time of molding release.
And tapered along the insertion direction of the strand 23. Therefore, the strand 23 can be easily inserted. In addition, in the illustrated example, it is provided at three places.

As shown in FIGS. 1 and 2, the strand insertion hole 1c is provided with a thin and flexible flange 1d. The thickness of the flange 1d is, for example, about 1 mm, and the diameter of the hole at the center is set to be smaller than the outer diameter of the strand 23 inserted therethrough.

As shown in FIG. 1, a tapered portion 1e for thickening the outer peripheral portion is formed in an upper opening portion of the curing tube 1, and further, an end flange portion 1f of the opening portion. Are formed.

As shown in FIG. 3, the head anchoring structure of the ground anchor using the curing tube 1 formed as described above is provided on a slope by, for example, a cast-in-place concrete frame, precast concrete, or steel. A reinforcing pipe or a penetrating pipe (steel casing or void pipe) 22 is fitted to a pressure receiving plate 20 which is a frame for hitting an anchor.

A required number of strands 23 are fixed at the bottom of the anchor hole 32 and the rear end thereof is projected on the ground surface. The stiffening plate 24 is placed on the pressure receiving plate surface B. A tapered surface 24b corresponding to the tapered surface of the tapered portion 1e is formed on the hole wall surface of the support hole 24a provided through the center of the stiffening plate 24.

The curing tube 1 has the strands 23 inserted through the strand insertion holes 1c of the bottom plate 1b, and the open ends are fitted into the support holes 24a of the stiffening plate 24. The flange portion 1d of the strand insertion hole 1c is raised upward, for example, as shown in FIG.
It comes into close contact with the outer peripheral surface of the strand 23.

As shown in FIG. 2B, in consideration of the ease of insertion and mounting of the strand 23, the diameter of the strand insertion hole 1c is made larger than the outer diameter of the strand 23, and The taper 1h of the peripheral wall 1c is also made slightly larger so as to form a space up to the vicinity of the flange 1d. With this structure, the resistance at the time of inserting the strand 23 into the strand insertion hole 1c is reduced, and insertion / attachment becomes easy. The internal space 1g of the curing tube 1 is filled with a rust preventive material.

Thereafter, a steel anchor plate 26 is placed on the stiffening plate 24. As a result, the flange portion 1f of the curing pipe 1 is connected to the stiffening plate 24 and the anchor plate 26.
And sandwiched between. Then, the strand 23 is fixed by the fixing nut 27 and the anchor head 28 after necessary tension. As a result, the flange portion 1f is strongly compressed, and water is stopped so that rainwater or the like does not enter from the outside. The anchor head 28 is covered with a protective cap 29 for rust prevention, rust-preventive oil is sealed in the inside, and the outer cap 30 is covered with the protective cap 29 as in the conventional case.

In the head anchoring structure of the ground anchor according to the present invention, as shown in FIGS. 3 and 4, the anchor hole 32 is drilled at an angle .theta. The strand insertion hole 1c
Since the edge of the hole of the flange 1d is thin and sufficiently flexible, it is wrapped around the outer periphery of the strand while being bent in accordance with the inclination / bias of the strand 23, and the adhesion is maintained.

In this manner, infiltration of groundwater or the like from the ground 31 to the pressure receiving plate 20 into the inside of the curing pipe is stopped by the flexible flange 1d, and the stiffening plate 24 and the anchor plate 26 sandwich the water.
The compressed flange portion 1f stops the penetration of rainwater and the like from the outside of the pressure receiving plate surface B into the inside of the curing pipe. In addition, the tapered portion 1e of the curing pipe 1 makes the root portion of the flange portion 1f and the main body portion 1a of the tubular body substantially orthogonal to the flange portion thicker on the outside, so that durability against cutting and crack generation is improved. It is obtained.

[0024]

As described above, the head anchoring structure for a ground anchor according to the present invention, in the head anchoring structure for a ground anchor, covers the back surface of the head of the ground anchor on the anchor hole side and has a bottom plate. The cylindrical curing pipe through which the strand is inserted is provided with a flexible flange for stopping water in the strand insertion hole provided in the bottom plate, so that there is an error in the drilling angle of the anchor hole. The flexible flange is deformed by its sufficient flexibility following the above, or the curing tube is also deformed by the flexibility, so that the water stopping property on the back side of the strand fixing portion is maintained for a long period of time. This is an excellent effect.

In the head anchoring structure for a ground anchor according to the present invention, in the head anchoring structure for a ground anchor, the back of the head of the ground anchor on the anchor hole side is inserted and the strand is inserted into the bottom plate. The tubular curing tube is supported by fitting the opening of the curing tube into a support hole of a stiffening plate placed on the pressure receiving plate,
Since the flange portion sandwiched between the stiffening plate and the anchor plate is provided at the opening of the curing tube, an excellent effect that the water stoppage on the surface side of the strand fixing portion is further improved is exhibited. Things. Further, the tapered surface of the curing pipe and the tapered surface of the auxiliary steel plate are brought into close contact with each other to improve the water stopping performance.

Since the outer peripheral portion of the opening of the curing tube supported by the support hole of the stiffening plate placed on the pressure receiving plate is formed to have a tapered portion which is made thicker on the outside, long-term durability is achieved. It has an excellent effect that the property can be obtained.

[Brief description of the drawings]

FIG. 1 is a half sectional view (A) and a bottom view (B) of a curing tube used for a head anchoring structure of a ground anchor according to the present invention.

FIGS. 2A and 2B are enlarged detailed views (A) and (B) of a portion A in FIG.

FIG. 3 is an explanatory view of a use state of the head anchoring structure of the ground anchor according to the present invention.

FIG. 4 is an explanatory view illustrating a state in which the strand and the flexible flange maintain close contact with each other in the ground anchor head fixing structure according to the present invention.

FIG. 5 is a cross-sectional view of a head anchoring structure of a ground anchor according to a conventional example.

FIG. 6 is an explanatory diagram showing a fitted state of a stiffening plate and a curing tube in the conventional example.

[Explanation of symbols]

1 Curing tube, 1a main body, 1b bottom plate, 1c strand insertion hole, 1d flexible flange, 1e taper,
1f flange, 1g internal space, 20 pressure plates,
21 pressure receiving plate through hole, 22 reinforcing pipe or through pipe, 23
Unbonded strand, 24 stiffening plate, 25 curing tube, 26 anchor plate, 27 anchor nut, 28
Anchor head, 31 ground, 32 anchor holes.

Claims (3)

[Claims] In a head anchoring structure for tensioning and anchoring a head of a ground anchor, a tubular curing pipe which covers a back portion of the head of the ground anchor on the side of an anchor hole and through which a strand is inserted into a bottom plate portion. The head anchoring structure for a ground anchor, wherein a flexible flange portion for stopping water is provided in a strand insertion hole provided in the bottom plate portion. 2. A head fixing structure for tensioning and fixing a head of a ground anchor, wherein a tubular curing pipe covers a back portion of the head of the ground anchor on the side of the anchor hole and a strand is inserted through a bottom plate. The opening of the curing pipe is fitted and supported in the support hole of the stiffening plate placed on the pressure receiving plate, and the opening of the curing pipe is inserted between the stiffening plate and the anchor plate. The head anchor structure of the ground anchor, wherein a flange portion to be sandwiched is provided. 3. An outer peripheral portion of an opening of a curing tube supported by a support hole of a stiffening plate placed on a pressure receiving plate is formed to have a tapered portion which is made thicker on the outside. The head anchoring structure for a ground anchor according to claim 1 or 2, wherein: