JPH0345167B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an earth anchor used in a method for reinforcing retaining walls in developed areas such as housing lots.

In recent years, as the development of residential land progresses, accidents involving retaining walls tend to increase. The main causes of such accidents are falls, tripping, movement, etc. In the case of such accidents, it is necessary to drive a large number of earth anchors through the retaining wall and connect these earth anchors to each other. This is commonly done. In this construction method using earth anchors, a tensile material is inserted into a drilled hole and then grout is injected to form an anchor body at the tip.However, in conventional construction methods, the pullout resistance per one In order to obtain sufficient force, it must be inserted deep into the ground, which requires large-sized equipment such as a hole-drilling machine, and requires assembly of erection equipment, resulting in a large-scale installation overall. However, it had the disadvantage of being expensive. The present invention has been made in view of the current situation, and aims to provide a retaining wall reinforcement method and an earth anchor that can be implemented at low cost. In order to solve the above problems, in this invention, at the tip of the hollow support to be inserted into the ground,
A wing is pivotally mounted on the tip side of the support device as a fulcrum and the tip of the proximal side of the support device opens outward, and the tip end of the support device has a slanted cam on the inner surface of the wing. An actuated tool is provided as an actuated surface, and the actuated tool is made to protrude into the support, and the inner end of a tensioning tool that is also inserted into the support and whose outer end protrudes from the support is provided. The present invention is characterized in that a cam portion is provided which moves within the support tool by pulling the tension tool outward and acts on the affected surface to open the blade.

Hereinafter, the structure of the present invention will be explained based on the illustrated embodiment. FIGS. 1 to 3 show a construction method using the earth anchor of the present invention. Drill a pilot hole 2 towards.
An example of a method for making such a pilot hole 2 is a method of driving a steel pipe pile into the hole and pulling it out. After drilling the pilot hole 2 as described above, insert the earth anchor 4 of the present invention having wings 3 at the tip into the pilot hole 2 as shown in FIG. 2, and then pull it out into the earth anchor 4. By applying force and moving outward, the wings 3 are opened like an umbrella. After opening the blade 3 as described above, as shown in FIG. 3, a grout material 5 such as cement milk is injected from the outside to cover the periphery of the blade 3 and harden to form an anchor body 6. do. Note that it is desirable that the grout material 5 be coated over almost the entire length of the earth anchor 4 if possible.

A plurality of such earth anchors 4 are inserted into one retaining wall, and when they are fixed, they are tensioned on the outside of the retaining wall 1 and are interconnected.
Note that there is also a method of directly driving the earth anchor 4 without drilling the pilot hole 2.

FIG. 4 and subsequent figures show the structure of the earth anchor 4 of the present invention. In the figures, 21 is a support pipe using a relatively short steel pipe, and the tip of this support pipe 21 has a semicircular cross section. Wings 3 and 3 are
A base end portion 3a is disposed along the outer circumferential surface of the support pipe 21 and is a pivot point for the wings 3, 3.
Pivot pieces 24, 24 are respectively fixed to the support pipe 2.
It is rotatably supported on a pin 25 attached to one tip, and is attached so that the tips protruding toward the proximal end side of the support pipes 21 of the wings 3, 3 open outward. Further, blade pieces 26, 26 are fixed to the inner surfaces of the wings 3, 3, respectively, in a state of protruding inwardly,
These blade pieces 26, 26 protrude into the support pipe 21 through slits 27, 27 formed in the support pipe 21, and overlap each other in this portion, and are connected to the pivot pin 2.
The end face on the 5 side is formed into inclined cam operated surfaces 28, 28.

Reference numeral 29 denotes a sliding rod inserted into the support pipe 21. A truncated conical cam 23 whose outer peripheral surface is inclined is fixed to the tip of the sliding rod 29. However, the blade pieces 26, 26
It faces the cam operated surfaces 28, 28 of. On the other hand, similarly, the other end of the sliding rod 29 is fixed to one end of the tensioning tool 22 led out to the outside, and when this tensioning tool 22 is pulled from the outside, the sliding rod 29 moves outward, that is, when the tensioning tool 22 is pulled from the outside. , so that it slides in the pulling direction. Reference numeral 30 indicates a disk-shaped slide plate fixed to the end of the sliding rod 29 at the portion where the tensioning tool 22 and the sliding rod 29 are fixed.

Reference numeral 31 denotes a donut-shaped slide guide fixed to the inner periphery of the support pipe 21 on the outside of the slide plate 30, so that the tension tool 22 slides inside the slide guide 31. It's summery. In this embodiment, the support pipe 21, tension tool 22, and wings 3, 3 are used as one anchor body 32, and in addition, in this embodiment, a long guide pipe 33 is used. The guide pipe 33 is made of a steel pipe having approximately the same diameter as the support pipe 21, and when inserted into the prepared hole 2, the tip of the guide pipe 33 comes into contact with the end of the support pipe 21, and the second As shown in the figure, the tensioning tool 22 is led out through the guide pipe 33.

Therefore, to explain the function of each part, first, as mentioned above, insert the anchor body 32 and the guide pipe 33 into the prepared hole 2, and then insert the anchor body 32 and the guide pipe 33 into the pilot hole 2.
By supporting the support pipe 21 externally,
When the tensioning tool 22 is pulled in the drawing direction in this state, the sliding rod 29 similarly slides outward, so that the cam 23 moves against the cam-actuated surfaces 28 and 28 of the blade pieces 26, 26. While sliding 28, the blade pieces 26,
26 outwards, thereby causing the wings 3,3
opens outward. Then, with the wings 3, 3 opened to a certain extent, the guide pipe 33 is pulled out, and then, when the tensioning tool 22 is pulled strongly in the pulling direction, the slide plate 30 moves to the slide guide 31.
At this time, the tips of the wings 3, 3 dig into the ground while the support pipe 21 moves outward, and the wings 3, 3 open further outward.

In addition, when the blades 3, 3 are fully opened, the sloped surfaces 3b, 3b at the base ends of the blades 3, 3 abut against each other to prevent further opening.

As can be understood from the above explanation, the earth anchor of the present invention has the tip wing opened and coats the wing with cement milk etc. to form the anchor body, so it has a small pull-out resistance. Even if the length of the tensile material is short, there is no need to insert it deep into the ground as in conventional construction methods, and only small equipment is required, and there is no need for construction-related equipment.
This can be carried out at low cost, and by moving the pulling tool in the pulling direction, the cam forcibly opens the blades to a certain extent, so the blades can be opened well. When the wing is opened to a certain extent, the tip of the wing digs into the ground, and the resistance force of the ground causes the wing to open, so there is no need to hold the support to prevent it from falling out until it is fully opened.
This has the effect of making the work easier. In addition, the support at the beginning of the wing opening need only be relatively weak enough to allow the wing to dig into the ground, so compared to the case where it is necessary to support the wing until the end, The advantage is that the device can also be made smaller. In addition, since the tips of the wings are located on the proximal end side of the support with respect to the pivot joint, there is no fear that the wings will open when inserted into the prepared hole, and in this respect as well, workability is excellent.

[Brief explanation of drawings]

1 to 3 are schematic vertical sectional views showing the construction method using the earth anchor of the present invention, FIG. 4 is a perspective view of the main part of the anchor body, and FIG. 5 is a vertical sectional view of the anchor body, Figure 6 is a longitudinal cross-sectional view showing the blades opened to a certain extent, Figure 7 is a cross-sectional view taken along line A-A in Figure 5, and Figure 8 is a vertical cross-sectional view of the blades covered with cement milk. , is. 21... Supporting device, 3... Wing, 22... Tensioning device,
23...cam, 4...earth anchor, 26...
Feather piece (worked tool).

Claims (1)

[Claims] 1. A wing is pivotally attached to the tip of a hollow support inserted into the ground, with the tip of the support on the proximal side opening outward with the tip of the support as a fulcrum, and a wing is attached to the inner surface of the wing. In this case, the tip end of the support device is provided with a cam surface that is slanted to be acted on, and the device to be acted on is made to protrude into the support device, and is also inserted into the support device. A cam portion is provided at the inner end of the tensioning tool whose outer end protrudes from the support, which moves within the support by pulling the tensioning tool outward and acts on the acted surface to open the wing. An earth anchor characterized by the following: