JP4451491B1 - Anchor device and installation method thereof - Google Patents

Abstract

[PROBLEMS] To prevent shear fracture of an anchor body with a simple structure, and to simplify construction and reduce costs.
An anchor device comprising an anchor body that is fixed in the ground and a holder cylinder that is externally mounted on a part of the anchor body, the anchor body having a self-piercing type fixing rod and one end of the fixing rod. An anchor rope connected to the head and having the other end exposed to the ground surface, and a joint tool fixed to one end of the anchor rope are provided.
[Selection] Figure 2

Description

  The present invention relates to an anchor device for applications in which a tensile force and a shear force act simultaneously, and more particularly to an anchor device suitable for mooring a protective fence on which impacts such as falling rocks, avalanches, and collapsible earth and sand act, and a method for installing the anchor device.

This type of protective fence includes a plurality of stay ropes that prevent the fence body from being tilted, and an anchor device fixes one end of the stay rope to the slope side.
As an anchor device used for a protective fence, an anchor device using a lock bolt as an anchor body is described in Patent Document 1, and an anchor device in which a lower end of a rope is connected to an upper end of a lock bolt as an anchor body is disclosed in Patent Document 2. Are listed.

  The anchor device described in Patent Document 1 embeds most of the lock bolt in the ground, connects one end of the lock rope to the base of the lock bolt protruding to the ground surface, and applies the tension acting on the lock rope to the strength of the lock bolt. The structure is supported by the adhesive force of the rock bolts embedded in the ground.

  The anchor device described in Patent Document 2 uses a pillow body having a circular cross section in addition to the anchor body, and a rope constituting a part of the anchor body is placed along the outer peripheral surface of the pillow body installed on the ground surface. One end of the holding rope is connected to the head, and the load direction acting on the lock bolt constituting a part of the anchor body can be changed by the combination of the rope constituting the pillow body and a part of the anchor body.

JP 2003-64693 A JP 2002-173934 A

The conventional anchor technique has the following problems.
<1> The anchor device disclosed in Patent Document 1 involves a drilling operation by a boring machine, and there is a problem that it takes a lot of time and labor to carry in and set the boring machine.
<2> Further, in the anchor device of Patent Document 1, when an unexpectedly large shearing force acts on the lock bolt through the holding rope, the root portion of the lock bolt is deformed, and worstly, shear failure is caused.
<3> The anchor device described in Patent Document 2 cannot obtain sufficient anchor strength because the rope does not function at all for pulling out resistance although the lock bolt constituting the anchor body resists pulling out.
Further, when the rope is deteriorated or damaged, it is not economical because it is necessary to reconstruct the entire anchor device because only the rope cannot be replaced.
<4> In the anchor body described in Patent Document 2, since the rope is bent into a “<” shape along the outer peripheral surface of the pillow body, when a large tension acts on the rope, the pillow body installed on the ground surface slides in the backward direction. Easy to do.
When the support position of the rope by the pillow body shifts, the rope in the ground tilts in the pulling direction, and there is a risk that the root portion of the rope connected to the lock bolt causes bending and shear failure.

The present invention has been made in view of the above points, and an object thereof is to provide at least one of the following anchor devices and an installation method thereof.
<1> Preventing shear fracture of the anchor body with a simple structure.
<2> Simplify construction and reduce costs.
<3> Sufficient anchor strength can be obtained even if the shaft length is short.

A first invention of the present invention is an anchor device comprising an anchor body that is fixed in the ground, and a holder tube that is externally mounted on a part of the anchor body and fixed in a work hole that is drilled in the ground. A fixing rod that anchors the anchor body in the ground, an anchor rope having one end connected to the head of the fixing rod, the other end exposed to the ground surface, and a joint tool fixed to one end of the anchor rope. The holder cylinder is attached to the upper end opening of the cylinder, includes a protective cap for inserting the anchor rope, and the anchor rope is detachably connected to the head of the fixing rod through the joint tool. An anchor device is provided.
A second invention of the present invention provides an anchor device according to the first invention, wherein a curved surface is formed on an inner peripheral surface of the protective cap, and an anchor rope is bent along the curved surface.
According to a third aspect of the present invention, there is provided the anchor device according to the first aspect or the second aspect, wherein the joint device can be inscribed in a holder tube.
According to a fourth aspect of the present invention, in the third aspect of the present invention, a narrow diameter portion that can be inscribed with the fixing rod is formed on the inner peripheral surface of the holder cylinder, and the anchor body and the holder cylinder are formed by the narrow diameter section and the joint tool. Provided is an anchor device characterized in that a load can be transmitted between the two.
A fifth invention of the present invention provides an anchor device according to any one of the first to fourth inventions, wherein a resistance plate is provided on the outer peripheral surface of the holder tube.
A sixth invention of the present invention is the anchor device installation method according to any one of the first to fourth inventions, wherein the fixing rod is fixed in the ground and the head of the fixing rod located in the work hole. An anchor rope is connected to the part via a joint tool, a holder cylinder is externally attached to a part of the anchor body located in the work hole, and a holder material is injected into the work hole to fix the holder cylinder. An anchor device installation method is provided.

The present invention can obtain at least one of the following effects.
<1> The anchor body can be prevented from being sheared with a simple structure in which the anchor rope and the anchor rod are connected with a joint tool and the holder cylinder is simply mounted on the joint tool.
<2> When the fixing rod is self-drilling, the drilling and fixing rod can be inserted in a single process, and a shallow depth working hole that can accommodate the holder cylinder can be easily drilled, simplifying construction. And cost reduction can be achieved.
<3> Not only the fixing power of the fixing rod fixed in the ground, but also the fixing power of the holder tube fixed to the caking material contributes to anchor strength.
Therefore, sufficient anchor strength can be obtained even when the axial length of the anchor body is short.
<4> Since the anchor rope can be separated into the head of the anchoring rod through the joint tool, the anchoring rod is reused as it is, and only the anchor rope that has deteriorated or damaged is replaced, and a new anchoring rod is reconstructed. Since it is not necessary, it is economical and the process can be shortened.
<5> Since the anchor rope exposed on the ground surface can be bent along the curved surface of the protective cap, breakage of the bent portion of the anchor rope due to the concentrated load can be prevented.
<6> Since the resistance resistance plate is attached to the holder cylinder, the shear resistance of the anchor body can be increased, so that the axial length of the working hole and the holder cylinder can be shortened.

Assembly drawing of anchor device according to the present invention Longitudinal cross section of anchor device anchored in the ground Model diagram for explaining the anchor device installation method Model diagram for explaining the characteristics of anchor devices anchored in the ground Cross-sectional view of the central portion of the anchor body for explaining another embodiment

  DESCRIPTION OF EMBODIMENTS Preferred embodiments for carrying out the invention will be described with reference to the drawings.

<1> Outline of Anchor Device FIGS. 1 and 2 show an example of an anchor device according to the present invention.
The anchor device according to the present invention includes an anchor body 10 that is inserted into the ground 60 and is fixed, and a holder cylinder 20 that is externally mounted on the anchor body 10.
The anchor body 10 includes a fixing rod 30, an anchor rope 40 that is connected to the head of the fixing rod 30 and exposed to the ground surface, and a joint tool 50 that joins the fixing rod 30 and the anchor rope 40. Each component will be described in detail below.

<2> Anchor body <2.1> Fixing rod The fixing rod 30 is an anchor material that is inserted into the ground 60 and fixed, and is made of a hard material that is difficult to deform, such as steel.
The fixing rod 30 is preferably self-drilling, but the fixing rod 30 is not limited to this, and a known hard anchor such as a steel rod can be used.
A male screw that can be connected to the joint tool 50 is formed on the outer peripheral surface of the head (base) of the fixing rod 30.

<2.2> Anchor Rope The anchor rope 40 is a flexible rope material that is exposed to the ground surface and connected to the guard rope of the protective fence, and is made of steel or high-strength fiber.
The total length of the anchor rope 40 may be long enough to guide to the ground surface.
One end of the anchor rope 40 is fixed to the joint tool 50.
Further, the end portion of the anchor rope 40 guided to the ground surface may be left as it is, or it can be connected to a tension generating source such as a holding rope via a shock absorber.

<2.3> Joint Tool The joint tool 50 i) functions as a connecting tool that connects the fixing rod 30 and the anchor rope 40 integrally, and ii) centers the fixing rod 30 and the anchor rope 40 with respect to the holder cylinder 20. Functions, and iii) a function to disperse and transmit the shearing force acting on the connecting part to the inner periphery of the holder cylinder 20 and the connecting part of the fixing rod 30 and the anchor rope 40, and iv) the fixing rod. 30 and a multifunctional member having a function of reinforcing the connecting portion of the anchor rope 40.

The joint tool 50 having a cylindrical shape as a whole has an outer diameter that can be inscribed in the holder cylinder 20.
The base end of the anchor rope 40 is fixed in advance to the shaft core of the upper half of the joint tool 50 by a known fixing means such as caulking.

A connecting hole 51 in which a female screw is formed is formed in the shaft center of the lower half portion of the joint tool 50 so that it can be connected to and separated from the head of the fixing rod 30.
The reason why the anchor rope 40 is configured to be connected to and separated from the head of the fixing rod 30 is to replace the aged anchor rope 40 together with the joint tool 50.

<3> Holder Cylinder The holder cylinder 20 is a strength member for preventing bending deformation and shear fracture of the connecting portion between the fixing rod 30 and the anchor rope 40, and its overall length is formed longer than the joint tool 50.

In the present invention, the joint tool 50 and the holder tube 20 function in cooperation to enhance the reinforcing effect of the connecting portion between the fixing rod 30 and the anchor rope 40.
In particular, the holder cylinder 20 is to increase the pressure receiving area by increasing the diameter of the connecting portion between the fixing rod 30 and the anchor rope 40 and to extend the load transmission range by increasing the axial length of the connecting portion. Useful.

  The holder cylinder 20 of this example will be described. An annular narrow-diameter portion 21 that can be inscribed with the fixing rod 30 inserted through the holder cylinder 20 is formed at the inner peripheral lower portion of the holder cylinder 20. A load is transmitted between the holder cylinder 20 and the fixing rod 30 via the narrow diameter portion 21. The narrow diameter portion 21 is not essential and may be omitted.

A protective cap 22 having an opening at the center is attached to the head of the holder tube 20.
The protective cap 22 is a member for preventing the anchor rope 40 from being deformed at an acute angle at the end of the holder tube 20, and a tube portion 23 that can be fitted to the holder tube 20 and one end of the tube portion 23 outward. And a flange 24 extending toward the surface.
The boundary portion between the cylindrical portion 23 and the flange portion 24 is formed on the curved surface 25 so that the anchor rope 40 inserted through the cylindrical portion 23 of the protective cap 22 can be curved in a curved manner.
The protective cap 22 can be screwed onto the holder cylinder 20 by forming a screw on the peripheral surfaces of the cylinder portion 23 and the holder cylinder 20 facing each other.
The protective cap 22 is formed of a hard material such as cast iron so as to resist a load acting through the anchor rope 40.

[Installation method of anchor device]
Next, a method for installing the anchor device will be described.

<1> Fixing of fixing rod As shown in FIG. 3A, after the working hole 61 is drilled in the ground 60, the fixing rod 30 is inserted into the working hole 61 to a predetermined depth and fixed.
The fixing rod 30 is not fixed from the ground surface, but is fixed from the back of the work hole 61.
As shown in FIG. 3B, the head of the fixing rod 30 is protruded into the work hole 61.

If the fixing rod 30 is self-drilling, the drilling and the insertion of the fixing rod 30 can be performed in one step only by using a simple punch 31 set on the fixing rod 30. Further, the shallow working hole 61 capable of accommodating the holder cylinder 20 can be easily drilled with a hand drill or the like, so that the construction can be simplified and the cost can be reduced.
Conventionally, it has been necessary to assemble a temporary scaffolding and install a large boring machine to cut an anchor hole having a depth that allows the full length of the anchor body to be inserted. However, in the present invention, the anchor hole itself is not necessary. It is possible to construct without using a scaffold or a large boring machine.

<2> Assembly of Anchor Device As shown in FIG. 3 (c), the joint device 50 having the anchor rope 40 fixed thereto in advance is connected to the head of the fixing rod 30 exposed in the working hole 61, and the anchor The holder cylinder 20 is mounted on the fixing rod 30 exposed in the rope 40, the joint tool 50, and the work hole 61.
It is desirable to position the head of the holder tube 20 at the last minute surface.

  The anchor rope 40 can be reliably connected to the fixing rod 30 that has been previously fixed by a simple operation of simply rotating the joint tool 50 at a position close to the ground surface in the work hole 61.

  A protective cap 22 is attached to the head of the holder cylinder 20 to complete the assembly of the anchor device.

<3> Injection of solidified material When the assembly of the anchor device is completed, a solidified material 62 such as mortar is injected into the working hole 61 as shown in FIG.
When injecting the consolidated material 62, it is important that the consolidated material 62 is not touched to the anchor rope 40 exposed from the protective cap 22 in order to ensure the degree of freedom of deformation of the anchor rope 40.

  Waiting for the solidified material 62 to harden, the end of the anchor rope 40 guided to the ground surface is connected to a tension source such as a guard rope of the protective fence.

[Characteristics of anchor device]
Next, the characteristics of the anchor device will be described.
<1> Fixing Structure of Anchor Body In FIG. 4, the fixing rod 30 constituting the anchor body 10 is embedded and fixed in the ground without being exposed to the ground surface, and the holder cylinder 20 sheathed on the anchor body 10 is a consolidated material. 62 is fixed.
Of the anchor rope 40 connected to the fixing rod 30, the exterior section by the holder cylinder 20 is positioned on the same axis as the fixing rod 30, and the exposed section protruding from the protective cap 22 is directed in a direction intersecting the axis of the fixing rod 30. It is stretched.

<2> Force acting on the anchor body When the external force F in the shearing direction indicated by the arrow acts on the anchor body 10 through the anchor rope 40, all the shearing force is transmitted to the holder cylinder 20 via the protective cap 22, Only the tensile force acts on the anchor body 10.
That is, only the axial pulling force acts on the anchor body 10 located in the holder cylinder 20.

<3> Pull-out resistance With respect to the pull-out force in the axial direction of the anchor body 10, the pull-out resistance in the fixing section of the fixing rod 30 fixed in the ground and the pull-out section in the fixing section of the holder cylinder 20 embedded in the caking material 62 are extracted. Resist and collaborate.
Therefore, in the present invention, as compared with the case where the anchor body is composed only of the fixing rod 30, a sufficient anchor strength can be obtained even if the fixing length portion fixed to the consolidated material 62 is short. It is economical.

The axial pull-out force acts as an axial tensile force on the connecting portion between the anchor rope 40 and the fixing rod 30.
Not only is the connecting portion of the anchor rope 40 and the anchor rod 30 firmly connected by the joint tool 50, but the connecting strength is reinforced by the restraining effect of the holder cylinder 20 that is externally mounted on the joint tool 50, so the connecting portion is destroyed. It will never be done.

<4> Shear Resistance As described above, the connecting portion of the anchor rope 40 and the fixing rod 30 is covered with the joint tool 50 and the holder cylinder 20.
Of the anchor rope 40 connected to the fixing rod 30, the exterior section by the holder cylinder 20 is positioned on the same axis as the fixing rod 30, and the exposed section protruding from the protective cap 22 is directed in a direction intersecting the axis of the fixing rod 30. Since it is stretched, the component of the tensile force in the direction orthogonal to the axis is transmitted to the holder cylinder as a shearing force through the protective cap 22.
Therefore, the shearing force is supported by a resistance force generated at the head portion and the lower portion of the holder tube 20 fixed to the binder 62 as shown in FIG.
Accordingly, the shearing force does not act on the anchor rope 40, the fixing rod 30 and the connecting portion thereof, and it is possible to prevent shear failure.
In particular, since the joint tool 50 has a function of transmitting and dispersing the shearing force acting on the connecting portion to the holder tube 20, the shearing force is dispersed throughout the holder tube 20, so that a large shear resistance is obtained.

<5> Bending resistance When the tension of the anchor rope 40 acts so as to cross the axis of the fixing rod 30, all the shearing force is transmitted to the holder cylinder 20 through the protective cap 22 and resists the shearing force. The ground reaction force shown in FIG.
When the ground is weak and cannot resist the shearing force, a bending moment is generated with the joint tool 50 and the narrow-diameter portion 21 as an arm.
If it is determined that the fixing rod 30 does not have sufficient strength against this bending moment, the length of the holder tube 20 may be increased.
Further, since the anchor rope 40 is bent along the curved surface 25 of the protective cap 22, it is possible to reliably prevent the bent portion of the anchor rope 40 from being broken due to the concentrated load.

<6> Replacing the anchor rope When the rope material 20 exposed on the ground surface is deteriorated or damaged due to use, the protective cap 22 is removed from the head of the holder tube 20, and the joint tool 50 is simply rotated in the disengagement direction. The anchor rope 40 can be separated from the fixing rod 30.
The anchor rope 40 with the joint tool 50 to be replaced can be replaced with a new anchor rope 40 simply by screwing it onto the fixing rod 30.
The fixing rod 30 is reused as it is, and it is not necessary to replace only the anchor rope 40 which has deteriorated or damaged, and to newly rebuild the anchor body, so that it is economical and the process can be shortened.

[Other Embodiments]
FIG. 5 shows another embodiment in which a resistance plate 26 is attached to the outer peripheral surface of the holder cylinder 20 to enhance the shear resistance of the anchor body 10.
The resistance plate 26 is fixed to the outer peripheral surface of the holder cylinder 20 by welding, bolting or the like.
The resistance plate 26 is provided over the entire length of the holder tube 20 or the head of the holder tube 20.

  By positioning the resistance plate 26 of the holder cylinder 20 on the acting direction side of the external force F, the shear resistance of the anchor body 10 can be increased, so that the axial lengths of the working hole 61 and the holder cylinder 20 can be shortened.

DESCRIPTION OF SYMBOLS 10 ... Anchor body 20 ... Holder cylinder 21 ... Narrow diameter part 22 ... Protective cap 30 ... Fixing rod 40 ... Anchor rope 50 ... Joint tool 62 ... Consolidating material

Claims (6)

An anchor device comprising an anchor body fixed in the ground, and a holder tube that is externally mounted on a part of the anchor body and fixed in a work hole cut in the ground,
A fixing anchor for fixing the anchor body in the ground;
One end can be connected to the head of the fixing rod, and the other end of the anchor rope exposed to the ground surface,
A joint tool fixed to one end of the anchor rope;
The holder cylinder is attached to the upper end opening of the cylinder and includes a protective cap for inserting an anchor rope;
An anchor device characterized in that an anchor rope is detachably connected to the head of a fixing rod through the joint tool.   2. The anchor device according to claim 1, wherein a curved surface is formed on an inner peripheral surface of the protective cap, and the anchor rope is bent along the curved surface.   The anchor device according to claim 1 or 2, wherein the joint tool can be inscribed in the holder tube.   4. A narrow diameter portion that can be inscribed with a fixing rod is formed on an inner peripheral surface of the holder cylinder, and a load can be transmitted between the anchor body and the holder cylinder by the narrow diameter portion and a joint tool. An anchor device characterized by.   The anchor device according to any one of claims 1 to 4, wherein a resistance plate is attached to an outer peripheral surface of the holder tube. An anchor device installation method according to any one of claims 1 to 5,
Fix the anchorage to the ground,
Connect the anchor rope via the joint tool to the head of the anchoring rod located in the work hole,
Cover the holder cylinder on a part of the anchor body located in the work hole,
An anchor device installation method characterized in that a holder tube is fixed by injecting a caking material into a working hole.

Images