JPH0651972B2 - How to fix the ground anchor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of fixing an earth anchor (including a so-called lock anchor) capable of checking the handedness of an anchor.

[Conventional technology]

As shown in FIGS. 5A and 5B, the sliding surfaces 10 and 11 are
When constructing the structures 14 and 15 on the inclined surfaces 12 and 13 having the above, it is widely practiced to construct the ground anchors 16 and 17 through the sliding surfaces 10 and 11.

As shown in FIG. 3, the earth anchor 17 (same for 16) is an anchor body 18 that serves as a resistance portion for transmitting a pulling force from the ground surface to the ground by shear resistance with the ground, and is connected to the anchor body 18. Pulling part 19
And the head portion 20 that is naturally connected to the pulling portion 19 by using the force from the structure 15 as a pulling force.

As a method of fixing the head 20, there are a method using a screw and a method using a wedge. The method using the screw is a pedestal 21 provided on the surface of the structure as shown in FIG.
The pressure bearing plate 22 is placed on the top of the anchor rod 23, and the nut 24, which is an example of a fastening metal fitting screwed to the head end of the anchor rod 23, is fastened to fix the building 15 (or 14). On the other hand, in the method using a wedge, a pulling member corresponding to the head is pulled by a jack with a predetermined load and fixed with a tightening fitting such as a wedge.

[Problems to be solved by the invention]

However, in the above-mentioned construction method, once the fastening metal fitting is fixed, it is unclear whether or not a predetermined tensile force acts on the anchor thereafter.

Therefore, it is necessary to inspect whether the above-mentioned tightening metal has been completely tightened, whether the anchor body has been broken, or if it is a permanent anchor, it should be checked regularly by pulling it with a jack or the like on the temporary anchor and every day. However, it is very difficult to carry around a heavy jack device because of the scaffolding, and it is extremely difficult to actually carry out the above-mentioned inspection for all earth anchors.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method of fixing an earth anchor by which the effectiveness of the earth anchor can be visually determined.

[Means for solving problems]

A method of fixing an earth anchor according to the present invention in accordance with the above object is to construct an anchor body at an appropriate depth in the ground, and to provide a plurality of truncated cone-shaped convex surfaces on one side between a pedestal of an anchor head and a bearing plate. The disc springs are fitted so that the conical convex surfaces of the adjacent disc springs face each other, and then the head clamps are mounted.

Here, the disc spring is usually formed of a metal plate having elastic force, and in a free state, the central portion is higher than the peripheral portion and has a truncated cone shape, but when pressed in the axial direction with a predetermined load. It is flat.

[Action]

In the method of fixing the earth anchor according to the present invention, a plurality of disc springs are provided between the pedestal of the anchor head and the bearing plate,
The conical frustoconical convex surfaces of the adjacent disc springs are arranged so as to face each other.

This disc spring becomes flat when a constant compressive force is applied in the axial direction and becomes a truncated cone when the force is removed. Therefore, if the anchor body slips and the tension is no longer applied, the disc springs will naturally have a truncated cone shape (when viewed from the side), and there will be a gap between the side edges of the adjacent disc springs. , It will be possible to judge the effectiveness of the earth anchor.

Here, when a larger number of disc springs are used and the conical convex surfaces of the adjacent disc springs are arranged so as to face each other, the displacement of the disc springs is enlarged, and thus the visibility can be improved. . It is considered from the prior art to use a spring washer, a part of which is cut out, instead of the disc spring, but when a spring washer is used, only one place is loose and the staggered part is stepped. Since it is not visible, it cannot be easily seen, but as in the present invention, the use of disc springs makes it evenly frustoconical,
The looseness can be determined from all directions. Also,
Since the current materials of spring washers are not constant, there are variations in the force that presses them into a flat surface, but in the case of disc springs, the force that results in a flat surface is constant and appropriate. The tightening force can be easily determined by selecting a disc spring for the.

〔Example〕

Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.

Here, FIG. 1 and FIG. 2 are partial cross-sectional views showing a method of fixing an earth anchor according to an embodiment of the present invention.

The method of fixing the earth anchor according to the first embodiment of the present invention is to drill a hole to a predetermined depth in advance and then pour a fixing agent such as cement into the tip by a conventional means to form an anchor body between the anchor body and the ground. After that, a pedestal 26 in which the metal plate 25 is embedded is provided on the surface of the built structure (it may be provided in advance), and a plurality of disc springs 31 to 34 are opposed to the protruding anchor rod 27. The disc springs 31 to 34
Is fitted, a bearing plate 29 made of a steel plate is fitted from above, and a nut 30 is screwed to the tip of the anchor rod 27. Here, the disc springs 31 to 34 are arranged such that the conical convex surfaces of adjacent disc springs face each other. A male screw having an appropriate length is engraved at the tip of the anchor rod 27, and the disc springs 31 to 34 are disc springs which selectively generate a proper pulling force according to the anchor body. And

After that, the nut 30 is rotated so that the disc springs 31 to 34 are made flat as shown in FIG. 2 so that a predetermined force is generated in the tension portion of the anchor rod 27 and the anchor rod 27 can be tightened. become.

Here, if there is an abnormality in the portion of the anchor body, the pressing force of the disc springs 31 to 34 is released and the disc springs 31 to 34 become a truncated cone shape, and a gap is formed between the pressure support plate 29 and the pedestal 26. This allows the abnormality of the anchor body to be easily judged from the outside.

That is, in the method of fixing the earth anchor shown in FIGS. 1 and 2, four disc springs 31 to 34 are used with their truncated cone-shaped convex surfaces facing each other. As a result, the restoration length (Σh−Σt) of the disc spring is four times as large as that in the case of one disc spring, so that the abnormality of the anchor can be easily detected from the outside. Here, Σt represents the thickness of the disc spring when tightened.

When an abnormality occurs in the anchor by applying yellow, red, or other paint to the front and back surfaces of the disc spring, the surface of the disc spring can be seen from the side and the abnormality of the anchor can be visually recognized.

〔The invention's effect〕

As is clear from the above description, the method for fixing the ground anchor according to the present invention, when abnormality occurs in the anchor body or other parts after the ground anchor is installed, the truncated cone-shaped convex surface attached to the flat surface is used. Since the plurality of coned disc springs have a truncated cone shape, the bearing plate floats up and the abnormality of the anchor can be visually inspected from the outside.

And in the method of the present invention, since a plurality of disc springs are mounted with their truncated cone-shaped convex surfaces facing each other,
When the earth anchor is loosened, a gap is created in the disc spring mounted with the truncated cone-shaped convex surfaces facing each other, and the gap can be visually observed. Therefore, the effectiveness of the earth anchor can be more easily determined.

In addition, the pressing force of the Belleville spring is more uniform than that of a spring washer, so a uniform tension force can be generated on the anchor rod. However, in the case of the Belleville spring, the whole is evenly frustoconical when viewed from the side, and therefore the abnormality of the anchor can be determined from all directions.

[Brief description of drawings]

1 and 2 are partial cross-sectional views showing a method for fixing an earth anchor according to an embodiment of the present invention, and FIGS. 3, 4, and 5 show a method for fixing an earth anchor according to a conventional example. FIG. [Explanation of reference numerals] 25 ... Metal plate, 26 ... Pedestal, 27 ... Anchor rod, 29 ... Bearing plate, 30 ... Nut, 31, 32, 3
3,34 ... Disc spring

Claims (1)

[Claims] 1. An anchor body is formed at an appropriate depth in the ground, and a plurality of disc springs each having a truncated cone-shaped convex surface on one side are provided between the pedestal of the anchor head and the bearing plate, and the adjacent discs. A method for fixing an earth anchor, characterized in that a conical convex surface of a spring is fitted to face each other, and then a fastening metal fitting of a head is mounted.