JPS6262209B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an anchor rod used in construction or civil engineering work. In particular, the present invention relates to anchor rods used for constructing or reinforcing retaining walls to prevent the collapse of steps of various sizes formed on land, such as cliffs, embankments, or river embankments.

(Prior Art) An anchor rod of this type has been provided with an enlarged tip in order to provide resistance to being pulled out from the ground. These anchor rods are usually manufactured at the construction site. For example, an anchor rod body consisting of a steel rod or steel pipe, which has a driving head fixed at its tip and a plurality of locking pieces that can be opened and closed by rotation and can be opened and closed, is attached to the driving head. Alternatively, insert a pre-drilled hole into the cutting, etc., then rotate the anchor rod body and use the locking piece to expand the anchor rod to excavate the surrounding soil layer, and then fill the hole with mortar, concrete or synthetic resin. Anchor rods having pull-out resistance were constructed by injecting the same into the anchor rod body to form a lump at the tip of the anchor rod body.

(Problems to be Solved by the Invention) However, the conventional anchor rod manufactured in this manner has a drawback in that the lump at the tip tends to be eccentric with respect to its axis.

In addition, in order to form a lump at the tip, a hole with a larger diameter than the pre-drilled hole must be made at the tip, so two types of excavators are required, or other means such as rotating the anchor rod body are required. Construction machinery was required, and moreover, the disposal of the soil created by re-excavation required ingenuity. As a result, conventional anchor rods have become expensive.

Furthermore, these problems in manufacturing conventional anchor rods have placed significant restrictions on integral construction, such as the construction of retaining walls. That is, in order to manufacture conventional anchor rods, it is necessary to drill holes with a relatively large diameter, making it difficult to construct retaining walls on soft embankments or cuttings. In addition, not only a large excavator but also other machines such as means for rotating the anchor rod are required, so moving these construction machines not only impairs work efficiency but also requires a relatively large construction area. This not only increases the number of days and costs required for construction, but also
The problem was that construction would be difficult in areas with a high concentration of people's homes and facilities.

(Objective of the Invention) The present invention has been made to improve the above-mentioned conventional drawbacks and eliminate the above-mentioned problems, and provides an anchor rod that can be manufactured extremely easily and has extremely high resistance to being pulled out of the ground. The purpose of the present invention is to provide an anchor rod that enables construction of retaining walls and the like to be carried out quickly and economically.

(Structure of the Invention) That is, the anchor rod of the present invention has a substantially U-shaped cut with the base facing the rear end of the anchor rod body and a substantially straight cut in the peripheral wall of the anchor rod main body made of a cylindrical body. In addition, a closing fitting is attached to the opening at the tip of the anchor rod body, so that an expansion agent can be injected and accommodated from the opening at the rear end of the anchor rod body.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is an exploded perspective view showing one embodiment of the present invention, and reference numeral 1 in the figure indicates an anchor rod body made of a cylindrical body made of metal or synthetic resin;
The peripheral wall has a U-shaped cut 2 whose base faces toward the rear end of the anchor rod main body 1, and a linear cut 3 along the longitudinal direction of the anchor rod main body 1.
Multiple pieces of each are provided. U-shaped tongue pieces 4 are formed by the cuts 2 . 2 and 3 are lines aa and bb of FIG. 1, respectively.
FIG. Reference numeral 5 denotes a closing metal fitting, and its rear end portion 5b is press-fitted and fixed into the tip opening 1a of the anchor rod main body 1, and is attached to the anchor rod body 1. The obturator 5 prevents soil from entering the anchor rod body 1 in the ground, and forms an expansion agent storage chamber into which the expansion agent can be injected and stored through the rear end opening 1b of the anchor rod body 1. This closing fitting 5 is for pouring,
The tip 5a has a sharp shape. In this way, anchor rod A is anchor rod body 1.
and a closing fitting 5.

As explained above, in the above embodiment,
A U-shaped cut 2 is made in the peripheral wall of the anchor rod body 1...
and linear cuts 3... and simply attaching the closing fitting 4 to the tip opening 1a, manufacturing is extremely easy and therefore inexpensive. After pouring or burying the anchor rod at the site, if an expansion agent is injected through the rear end opening 1b of the anchor rod main body 1,
Due to the expansion pressure, the U-shaped tongues 4 stand up, the anchor rod body 1 around them expands, and as the cracks in the linear cuts 3 expand,
Due to the enlargement of the anchor rod body 1 around it, the pull-out resistance of the anchor rod A in the ground becomes significantly high. Furthermore, as will be explained in detail below, it is only necessary to make cuts 2..., 3... in the peripheral wall of the anchor rod body 1 at the factory and then pour the holes at the site. Since it is only necessary to drill a hole with a diameter approximately equal to that of the ground, construction of retaining walls and the like can be carried out quickly and economically.

In the above embodiment, the anchor rod body 1 is made of a cylindrical body, but a hollow prismatic body may also be adopted. The shape of the cut 2 is not limited to a strict U-shape, and may be, for example, a square shape, a square shape, a semicircle, a U shape, or a V shape, and the base thereof should face the rear end of the anchor rod body 1. However, its shape does not matter. The substantially linear cuts 3 may also be provided not only in the longitudinal direction of the anchor rod body 1 but also along the circumference. Furthermore, the number of cuts 2..., 3... is preferably as large as possible as long as it does not significantly affect the strength of the anchor rod body 1, but it is preferable to provide them as close to the tip of the anchor rod body 1 as possible, and 3 cuts on the same circumference of the peripheral wall. It is sufficient to provide at least a few locations. In this case, substantially U-shaped cuts 2 and substantially straight cuts 3 may be provided alternately on the same circumference.

Further, in the above embodiment, the anchor rod main body 1 and the closing fitting 5 are separate members, but they may be formed integrally, or the tip opening 1a of the anchor rod main body 1 and the rear end portion 5b of the closing fitting 5 may be connected to each other. It may also be screwed together. For embedding, a closing metal fitting with a flat tip as shown in FIG. 4 may be used.

Hereinafter, the functions and effects of the anchor rod of the present invention will be explained in more detail by explaining an example of a retaining wall reinforcement method that can be carried out by employing the anchor rod A of the above embodiment.

First, as shown in FIG. 5, a plurality of anchor rods A of the above embodiment are inserted into the embankment 8 at acute angles to the vertical axis of the retaining wall through holes 7 bored at predetermined intervals in the retaining wall 6. Drive to desired depth. It is preferable that the anchor rod A is relatively short when driven into the upper part of the retaining wall 6, and becomes gradually longer towards the lower part. However, the method is not necessarily limited to this, and long anchor rods and short anchor rods may be driven alternately. In addition, it is preferable to use a long anchor rod if the ground is soft.

Each anchor rod A driven in this way...
The swelling agent 9 is injected from the rear end opening 1b to the position where the cuts 2..., 3... are provided. This swelling agent 9
is a mixture of inorganic compounds mainly composed of silicates, specific organic compounds, and water. For example, a mixture of BLISTER (trade name) manufactured by Onoda Cement Co., Ltd. and water can be suitably used. Note that a mixture of this expanding agent with a small amount of cement, mortar, etc. may also be used.

The injected swelling agent 9 hardens enormously, usually about 12 to 24
As time elapses, the maximum inflation pressure is reached, and as shown in FIG. 6, the U-shaped tongues 4 stand up due to this inflation pressure, and the anchor rod A is given a pulling resistance force. At the same time, a frictional force is applied to the anchor rod A due to the enlargement of the peripheral portion of the anchor rod body 1 (enlarged portion 10) as the cracks in the cuts 3 expand. Fig. 7 is a partial perspective view of the anchor rod main body 1 showing a state in which the tongue pieces 4 are erected and the cuts 3 are cracked, and Fig. 8 is a partial perspective view of the anchor rod body 1 shown in Fig. 7 with the expansion agent omitted. Line sectional view, 6th
The figure is a sectional view taken along line dd in FIG. 7, with the expansion agent omitted. Coupled with the uprighting of the tongue pieces 4..., the peripheral part of the cuts 2... of the anchor rod body 1 expands (bulges 11...), and the surrounding swelling parts 10... of the cuts 3 of the cylindrical body 1 cause the soil layer around them to expand. Compressive stress is applied to the material and consolidation occurs. As a result, a large frictional force is generated between the anchor rod A and the embankment. As a result, the pull-out resistance of the anchor rod A becomes extremely high.

After the expansion of the expansion agent 9 is completed, a closing fitting is attached to the upper end opening of each anchor rod A projecting from the retaining wall 6, and tension is applied to each anchor rod A using a tightening means such as a nut. By applying tension in this way, the tongues 4 are further erected due to the resistance of the embankment, and the pull-out resistance of the anchor rods A is further increased.

In the manner described above, the reinforcement of the retaining wall employing the above embodiment of the anchor rod of the present invention is completed. Incidentally, if the rear end of each anchor rod A is undesirably exposed from the retaining wall, a surface layer may be coated thereon.

When reinforcing a retaining wall in this way, the pull-out resistance and friction properties of the anchor rod A of the above embodiment of the present invention are extremely high, so even if relatively short and small rods are used, sufficient effects can be achieved, and the arrangement It is also possible to reduce the number of devices. Furthermore, good stability can be imparted even to a thin retaining wall such as a concrete layer constructed using a spray construction method. Furthermore, since it is only necessary to make cuts 2..., 3... in the peripheral wall of the anchor rod body 1 at the factory and then cast or bury it on site, there is no need for many construction machines, and therefore it is easy to move the construction machines on site. becomes. As a result, even if the temporary scaffolding is simple, there will be no inconvenience during construction, and construction efficiency will be extremely high. Therefore, the number of on-site workers is reduced, making it possible to save labor, and construction can be carried out easily and quickly even in areas with densely populated houses and facilities.

(Effects of the Invention) As explained above, according to the present invention, an anchor rod is provided that is extremely easy to manufacture and has extremely high pull-out resistance and friction properties in the ground.
Furthermore, it is possible to provide an anchor rod that allows construction of retaining walls and the like to be carried out quickly and economically.

[Brief explanation of the drawing]

Fig. 1 is an exploded partial perspective view showing an embodiment of the present invention, Fig. 2 is a sectional view taken along line a-a of Fig. 1, Fig. 3 is a sectional view taken along line bb-b of Fig. 1, and Fig. 4 is a sectional view taken along line bb of Fig. 1. 5 is a perspective view showing another embodiment of the closure fitting, and FIG. 5 shows the above embodiment,
Fig. 6 is a partial cross-sectional view showing the state in which the retaining wall is driven into the embankment through a hole provided in the retaining wall, and the tongue piece formed in the above example is erected due to the expansion pressure of the expansion agent in the embankment. Fig. 7 is a partial cross-sectional view showing a state in which the tongues are erected, the cracks in the cuts have expanded, and the surrounding areas have expanded. A perspective view of the essential parts of the above embodiment showing the state; FIG. 8 is a cross-sectional view taken along line CC in FIG. 7, with the swelling agent omitted; FIG. 9 is a sectional view with the swelling agent omitted; FIG. 7; FIG. 2 is a sectional view taken along line dd. A... Anchor rod, 1... Anchor rod body, 2, 3... Cut, 4... Tongue piece, 5... Closure fitting, 6... Retaining wall, 8... Embankment, 9... Expansion agent,
10, 11... vast section.

Claims (1)

[Claims] 1 A substantially U-shaped cut with the base facing the rear end of the anchor rod body and a substantially straight cut are provided on the peripheral wall of the anchor rod body consisting of a cylindrical body, and a closing metal fitting is provided at the tip opening of the anchor rod body. 1. An anchor rod characterized in that the anchor rod is configured such that an expansion agent can be injected and accommodated from the rear end opening of the anchor rod main body.