JP2009079434A - High pressure bearing anchor for earth covering section - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high pressure bearing anchor for an earth covering section, which has a simple structure and an enhanced bearing force with achieving drastic reduction in displacement, in the case of being applied to a site where a ground surface layer of 40-140 cm in depth consists of earth and sand and the layer under the surface layer consists of rock. <P>SOLUTION: The high pressure bearing anchor comprises an anchor body made of a steel bar, a tubular resisting body driven into the ground with the head of the anchor body positioned to the downside and a reinforcement tube body having a tabular section with holes made in the upper and lower sections thereof and having a size to allow the anchor body to pass through. The tubular resisting body has a top plate section of a size avoiding contact with the head section of the anchor body. A ring for forming a contact point, which is passed through the reinforcement tube body, is provided in a tube section. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an anchor, particularly to a high strength anchor for a covering portion.

In facilities such as rockfall prevention and avalanche prevention, it is necessary to fix the rope ends along the ground and fix the rope ends. As such rope fixing means, an anchor that attaches a rope to the top and resists the pulling force against the rope generated by falling rocks or avalanches is used.
As such an anchor, in addition to an anchor that is driven into the soil, there is a soil covering anchor that is used when a ground surface portion having a depth of about 40 to 140 cm is made of earth and sand, and a lower portion is a rock portion.

Regarding this anchor, in order to increase the yield strength against the lateral pulling force and suppress the displacement, the anchor tip was rocked with cement and the like, and radial blades were driven from the anchor head for integration. There is something.
However, since this anchor has different resistance to earth pressure depending on the direction of the cruciform blade, there is a problem in that the displacement varies greatly depending on the geology and soil volume.

As a means for solving the problem, Japanese Patent Application Laid-Open No. 2006-183232 discloses an anchor main body made of a steel bar and having a required length at the lower end portion embedded in a rock with cement, and the head of the anchor main body is covered. The cylindrical resistor is pushed into the ground surface, and the cylindrical resistor is provided with a top plate portion that allows the anchor body to be inserted at the upper end, and the top plate of the cylindrical resistor is provided on the head of the anchor body. An anchor is disclosed in which a flat washer that comes into contact with a portion is inserted into an anchor body and fixed with a nut.

According to this prior art, the center position of the anchor's overturning behavior can be replaced from the lower end of the anchor to the ground (ground), the overturning moment acting on the anchor can be minimized, and the resistor is a radial plate Since it is cylindrical and has no directivity, it is described that it can exert a good resistance action even if it receives external force from any direction of 360 degrees, but the anchor body is a steel rod Since the gap between the inner surface of the cylindrical resistor is large and the contact point with the cylindrical resistor is only the top plate portion of the cylindrical resistor, the cylindrical resistor is inclined according to the displacement of the anchor body, Depending on the amount of soil, there was a problem that the amount of displacement varied greatly.
In addition, the steel rod is usually 22 mm to 25 mm in diameter and is weak against bending resistance. When the cylindrical resistor is pushed by such an anchor head, it is bent by the load applied to the anchor head, thereby causing the cylindrical resistance. The body was inclined and the displacement tended to increase.
JP 2006-183232 A

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is that the construction site has a depth of about 40 to 140 cm, the ground surface portion is made of earth and sand, and the lower portion is a rock portion. In such a case (earth covering portion), it is an object to provide a high strength anchor for a soil covering portion which has a simple structure and can increase the yield strength and greatly suppress the amount of displacement.

  In order to achieve the above object, the present invention provides an anchor main body made of steel bar, a cylindrical resistor positioned below the head of the anchor main body and pushed into the ground, and a hole that allows the anchor main body to be inserted into the upper and lower portions. The cylindrical resistor has a top plate portion of a size that does not come into contact with the anchor main body head, and the reinforcing cylinder is provided in the cylindrical portion. It is characterized by having a ring for contact formation for inserting the shaped body.

According to the present invention, since the resistor has a cylindrical shape, there is no directionality, and even when an external force is applied from any direction of 360 degrees, a good resistance action can be exhibited.
A reinforcing cylindrical body is used, and there are holes in the upper and lower parts that allow the anchor body to be inserted, and there is little difference in the hole diameter between the anchor body and the reinforcing cylindrical body. The bending resistance of the anchor body can be reinforced, and the mechanical performance of the anchor body can be greatly reinforced.
Further, by increasing the hole diameter of the top plate portion of the cylindrical resistor, the contact point of the anchor body and the reinforcing cylindrical body with the cylindrical resistor is only the ring portion inside the cylindrical resistor. Since the anchor body and the cylindrical resistor are not joined at the anchor head, only the ring portion inside the anchor body and the cylindrical resistor is pushed, and the inclination of the cylindrical resistor can be suppressed. Furthermore, since the load is applied to the inside of the ground having a greater ground strength, the strength can be increased.
As described above, it is possible to obtain an excellent effect that an anchor with enhanced proof stress and greatly reduced displacement can be realized as compared with the conventional method.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1 to 4 show an embodiment of a high strength anchor for earth covering according to the present invention. Reference numeral 1 denotes an anchor according to the present invention, and a soil layer A having a depth of about 40 to 140 cm and a layer below it. It is constructed on the ground consisting of the bedrock part B. R is a wire rope fixed by an anchor, and in this example, an eye 9 is formed by a winding grip 90 at the end.
The anchor 1 of the present invention includes an anchor main body 2 made of a deformed steel bar having a total length of 1500 to 2000 mm, a reinforcing cylindrical body 3 set on an upper portion of the earth and sand layer, and the reinforcing cylindrical body 3. A cylindrical resistor 4 having a sufficiently large diameter and pushed into the sediment layer from the surface of the sediment layer, a rope pressing means 5 attached to the head 20 having a male thread portion of the anchor main body 2, and this are tightened. It consists of a double nut 6.

The reinforcing cylindrical body 3 is selected from a steel pipe or a tough synthetic resin molded body, and the entire length is substantially the same as that of the cylindrical resistor 4. The reinforcing cylindrical body 3 has plate-like portions (inner flanges) 30 and 30 having holes 300 and 300 having a size capable of inserting the anchor main body 2 at least at an upper end portion and a lower end portion.
The rope pressing means 5 has a washer shape in this example, and the eye 9 fitted to the head 20 of the anchor main body 2 is pressed from the upper part to the plate-like part 30 at the upper end of the reinforcing cylindrical body 3, However, the present invention is not limited to this, and a two-piece presser fitting that fastens the rope from above and below may be used.

The cylindrical resistor 4 is made of a steel pipe, and has a cylindrical portion 40 having a sharpened portion at the lower end portion and a top plate portion 41 fixed to the upper end thereof by welding or the like. The head portion 20 of the anchor main body 2 and the rope pressing means 5 are the hole portions 410 having a large hole diameter that do not come into contact with each other.
The cylindrical resistor 4 has a contact forming ring 42 having a diameter substantially equal to or slightly smaller than the outer diameter of the reinforcing cylindrical body 3 in the cylindrical portion 40 via a plurality of centripetal ribs 420. Provided.

In addition, the specification of the cylindrical resistor 4 has a diameter that is 1.5 times or more the diameter of the anchor body as in the prior art, and the effective height is horizontal load: T / (cylinder part diameter: D × It may be ± 20% of the side compression strength of the soil (σ).

For construction, carry it in the disassembled state as shown in Fig. 4, temporarily remove the earth and sand at the construction site, drill the rock section with a rock drill, etc., and insert cement or other fixing material C into this To fix the lower part of the anchor body.
Then, the earth and sand are backfilled to form a covering, but the rope pressing means 5 is not attached at this time, and the reinforcing cylindrical body 3 is extrapolated to the head 20 of the anchor body. The reinforcing cylindrical body 3 is not displaced in the radial direction from the anchor body 2 by the upper and lower holes 300, 300. Next, the cylindrical resistor 4 is pushed concentrically with the reinforcing cylindrical body 3 from the ground surface side into the earth and sand part.
The cylindrical resistor 4 has a contact forming ring 42 at a position below the middle in the height direction, and the contact forming ring 42 may be in light contact with the outer diameter of the reinforcing cylindrical body 3. However, they may be separated.

Then, the rope R is fixed by fitting the rope pressing means 5 to the male screw portion of the head 20 of the anchor body 2 and tightening with the nut 8. In this state, the hole 410 of the top plate portion 41 of the cylindrical resistor 4 is sufficiently larger than the outer diameter of the anchor main body 2 or the reinforcing cylindrical body 3, and the cylindrical resistor 4 has the anchor main body head or the rope pressing means 5. It is not pressed at all.

  For this reason, the problem that the cylindrical resistor 4 tilts due to the load applied to the head of the anchor main body 2 and the displacement becomes large is solved, and the reinforcing cylindrical body 3 is attached to the anchor head 20 as a reinforcement of the anchor main body 2. Since the bending resistance force of the anchor is increased by inserting it into the earth and sand part A, and the contact between the reinforcing cylindrical body 3 and the cylindrical resistor 4 is only the ring 42 in the cylindrical resistor body, the cylindrical resistor 4 By applying a load only to the lower part of the ground, the load applied to the ground became more stable inside the ground, reinforcing the anchor strength and greatly reducing the amount of displacement.

An irregular steel bar with a diameter of 22 mm and a length of 1500 mm is used as the anchor body. Figure 5 shows the result of measuring the type and load variation curve in the prior art using a 430mm x outer diameter of 114mm and a hole with a diameter of 28mm on the upper and lower end plates. It can be seen that such a load also becomes more stable inside the ground, anchor strength is reinforced, and the amount of displacement can be greatly improved.

It is a top view which shows one Example of the high yield strength anchors for earth covering parts by this invention. It is sectional drawing similarly. FIG. 3 is a cross-sectional view of FIG. 2. It is a perspective view which shows component structure. It is a load displacement curve figure of this invention and the conventional anchor.

Explanation of symbols

2 Anchor body 3 Reinforced cylindrical body
30, 30 Plate-shaped portion 300, 300 Hole 4 Cylindrical resistor 40 Tube portion 41 Top plate portion 410 Hole 42 Ring for contact formation

Claims (1)

Reinforcement with an anchor body made of steel bar, a cylindrical resistor located under the head of the anchor body and pushed into the ground, and a plate-like part with holes at the top and bottom where the anchor body can be inserted The cylindrical resistor has a top plate portion of a size that does not come into contact with the anchor main body head, and the contact forming ring through which the reinforcing cylindrical body is inserted. A high-strength anchor for earth covering, characterized by having

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