JPS6323330B2 - - 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 pull-out resistance of each must be inserted deep underground to ensure sufficient
Therefore, large-sized equipment such as a hole drilling machine is required, and assembly of erection equipment is required, resulting in a large-scale construction as a whole, resulting in high costs. In order to solve these drawbacks, as disclosed in Japanese Patent Publication No. 57-30938 and Utility Model Application No. 52-9433, a wing that is forcibly opened at the tip of the anchor inserted into the ground has been proposed. There are some types that increase the resistance to pulling out. However, in these conventional methods, when opening the wings, the anchor body is pulled upward, which causes the position of the anchor body to change, making it difficult to manage the position. be. The present invention overcomes the drawbacks of the conventional earth anchor with wings.

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, the earth anchor 4 of the present invention having a wing 3 at the tip is inserted into the pilot hole 2 as shown in FIG. 2, and then connected to the wing 3. By pulling the tension tool 5, the wings 3 are opened into an umbrella shape. As above,
After opening the blade 3, as shown in FIG. 3, a grout material 6 such as cement milk is injected from the outside to cover the periphery of the blade 3 and harden to form the anchor body 22. Note that it is desirable that the grout material 6 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 connected to each other.
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, and the earth anchor main body 7, which serves as a tensile member, is made of a steel pipe having a sufficient length to be inserted into the ground. Two wings 3, 3 having a semicircular cross section are used, and these wings 3, 3 are arranged along the longitudinal direction around the outer periphery of the tip of the anchor body 7. Further, pivot pieces 8, 8 are fixed to the base ends, which are pivot points, of these wings 3, 3, protruding from the inner surfaces thereof.
The pivot pieces 8, 8 are rotatably attached by a pivot pin 9 attached to the tip of the anchor body 7, and the tips of the wings 3, 3 are pivoted outward with the pivot pin 9 as a fulcrum. It is installed so that it opens. 10,
10 is a pair of link pieces, one ends of these link pieces 10, 10 are mutually connected with a pin 11 to constitute one connecting link 21,
The other end protrudes outward through slits 12, 13 formed in the anchor body 7 and wings 3, 3, and engages pins 14, 14 attached to the tips thereof.
is fitted into the engagement hole 15 of the wings 3,3. A rod-shaped tensioning tool 16 led out through the interior of the anchor body 7 has its inner end connected to one end of a connecting tool 17, and the connecting tool 17 is bifurcated.
The other end is pivotally connected to a pin 11 which pivotally connects the link pieces 10, 10 to each other. Reference numeral 18 denotes a disc-shaped slide guide attached to the end on the side where the connecting tool 17 and the tensioning tool 16 are fixed, and this slide guide 18 slides on the inner surface of the anchor body 7.

Therefore, in the above structure, when the anchor body 7 is inserted into the pilot hole 2, the outer end of the anchor body 7 is held down by some means, and the tensioning tool 16 is pulled outward. Via the connecting links 10, 10, the wings 3, 3 are forced to open outwards. FIG. 8 shows the blades 3, 3 opened and then covered with cement milk grout 6.

FIG. 9 shows another embodiment of the present invention, in which projections such as nuts 19, 19 are provided on the outer periphery of the anchor bodies 7, 7, corresponding to the inner surfaces of the tips of the wings 3, 3. The blades 3 are held in a slightly open state in advance.

The present invention has the above-mentioned configuration, and according to the present invention, with the wings provided at the tip of the anchor body in an open state, the wing portion is coated with cement milk or the like to close the anchor body. Because it is a form of material, it has a high pull-out strength despite its simple construction, and even if the length of the tensile material is short, it has a relatively high pull-out strength. It can be carried out at low cost because it does not require any construction equipment and does not require construction-related equipment. Since it is forced to open, it has the effect of ensuring that it opens.

In particular, according to the present invention, since the connecting link for opening the wings projects outward from the slit in the anchor body and is connected to the wings, when the bent part of the connecting link is pulled, Not only does the link slide against the end of the slit to ensure that it is opened, but the anchor body is also supported by some means to hold it in that position, so that when the tensioner is pulled, the anchor body Since the wings open outward while remaining in the same position, the burial depth of the anchor body inserted into the ground does not change at all times, and the wings pivoted to the anchor body also open in that position, making it easier to form the anchor. It is easy to control the depth at which the anchor body is moved, and there is no need to drill the hole to an extra depth in consideration of the amount of movement of the anchor body.

[Brief explanation of the drawing]

Figures 1 to 3 are schematic vertical cross-sectional views showing the construction method using the earth anchor of the present invention, and Figure 4 is a
A perspective view of the tip of the earth anchor of the present invention, FIG. 5 is a longitudinal cross-sectional view, and FIG. 6 is an A-A in FIG.
7 is a sectional view taken along the line B--B, FIG. 8 is a perspective view showing the wing portion coated with cement milk, and FIG. 9 is a sectional view showing another embodiment of the present invention. It is a front view of the anchor main body tip part shown. 3... Wing, 7... Anchor body, 5... Tension tool, 1
2, 13...Slit, 21...Connection link.

Claims (1)

[Claims] 1 A pair of wings 3, 3 that open outward with the tip side of the anchor body 7 as a fulcrum are pivotally attached to the tip of a pipe-shaped anchor body 7 inserted into the ground, and a connecting link 21 is bent at an intermediate portion thereof. A bent portion of the anchor body 7 is disposed within the anchor body 7, and both ends of the bent portion protrude outward from slits 12, 13 formed in the anchor body 7, and are pivotally connected to the opening and closing ends of the wings 3, 3, An earth anchor characterized in that a tensioning tool 5 connected to the bent portion of the connecting link 21 is led out through the interior of the anchor body 7.