JPH0632984Y2 - Removable ground anchor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] This draft relates to a removable ground anchor that can be reused as a tension anchor that is installed temporarily.

[Prior art]

Temporary ground anchors have been developed to be used for damming. In such a ground anchor, it is necessary to pull out the tension material buried in the ground after the temporary construction is completed. Steel is often used as the material for such tensile members.

[Problems to be solved by this device]

In the case of the tensile member using the steel material as described above, since it is buried in the ground containing water, it is corroded or damaged, and there is almost no reusable material. It was extremely uneconomical to use a tension material every time the construction was performed, and the construction cost was high.

The present invention has been made to solve the above problems, and an object thereof is to provide a removable ground anchor that enables reuse of a tensile member and can be easily pulled out from the ground. To do.

[Means for Solving the Problems]

The removable ground anchor according to the present invention uses a carbon fiber reinforced plastic rod as a tensile member.

The carbon fiber reinforced plastic is a composite material of carbon fiber and plastic, and epoxy resin, polyester resin or the like can be adopted as the plastic. The reason for using a composite material of carbon fiber and plastic is that when a tensile force is applied to a bundle of carbon fibers alone, each fiber will not be subjected to uniform stress and progressive fracture will occur. To strengthen.

Insert the tip part of this tension material into a cylindrical fixture and fix it with grout material, insert this fixture into the tip cap fixed with grout material in the inner part of the drilling hole, and support it with the support plate of the tip cap. To do.

A heating coil is wound around the outer periphery of the portion of the tension member protruding from the tip cap. Since the carbon fiber reinforced plastic rod has a low electric resistance value and current leaks to the rod, an insulating material is interposed between the heating coil and the rod. As the insulating material, a ceramic insulator or the like can be considered.

[Action]

The carbon fiber reinforced plastic rod is rust-free and non-corrosive and can be used even after being removed from the ground. An electric current is applied to the heating coil to deteriorate and cut the resin portion of the carbon fiber reinforced plastic rod, which has poor heat resistance.

〔Example〕

Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

In the figure, 1 is a carbon fiber reinforced plastic rod, which is manufactured by reinforcing carbon fiber with an epoxy resin.

Unevenness is formed on the outer periphery of the end of the rod 1,
Support plate 1 with this end attached to a casting-made tip cap 2
Each of the rods 1 is fixed to a cylindrical rod fixing tool 3 by inserting it through the insertion hole 3 into the tip cap 2. The rod fixture 3 is filled with the grout material 4 and hardened and fixed. The tip of the rod 1 is slightly projected from the rod fixture 3.

The heating coil 5 is wound around the outer periphery of the rod 1 and at a position close to the tip cap 2. A ceramic insulator 6 is attached to the heating coil 5 in a beaded shape on the outer periphery thereof and is wound around the rod 1. An insulating tape 7 is wrapped around this, and an epoxy resin 8 is coated on the insulating tape 7.

When a plurality of rods 1 and 1 are used as tension members, the heating coils 5 wound around the rods 1 and 1 are connected to each other, and the end of the heating coil 5 is insulated from the terminal 9 at the end of the rod 1 in the tip cap. Connect with a conductor.

The removable ground anchor configured as described above is inserted into the drilled hole 10 formed in the ground. Grout material 4 in drill hole 10
To fix the inside of the tip cap 2 into the drilled hole 10.

The carbon fiber reinforced plastic rod 1 has a weak adhesive force with the grout material 4, and even if it is not put in the sheath, the tip cap 2
The more protruding part becomes a free length part, which is stretched by the tensile force.

When the tensile member is removed, the carbon fiber-strength plastic rod 1 having good electrical conductivity is energized and heat is generated from the heating coil 5. This heat deteriorates the rod 1 and allows it to be pulled out with a low tensile force.

As another embodiment of the present invention, as shown in FIGS. 3 and 4, cylindrical insulators 11 and 12 are attached to the outer periphery of the rod 1, and the heating coil 5 is wound between the insulators 11 and 12. May be.

[Effect of device]

The present invention has the above-mentioned configuration and can obtain the following effects.

B. Carbon fiber reinforced plastic rod is free from rust and corrosion and can be reused after being removed.

(B) A heating coil can be wound around and ruptured by heat, and can be easily removed.

(C) Since the end portion of the heating coil and the terminal at the end portion of the carbon fiber reinforced plastic are connected by the lead wire in the tip cap, the means for supplying the electric current to the heating coil can be simple and inexpensive, and there is no possibility of leakage.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a removable ground anchor according to the present invention, FIG. 2 is a partially enlarged view of FIG. 3, FIG. 3 is a partially enlarged view of another embodiment, and FIG. FIG. 1 ... Carbon fiber reinforced plastic rod, 2 ... Tip cap, 3 ... Rod fixing tool, 4 ... Grout material, 5 ...
… Heating coil, 6 …… Insulator, 7 …… Insulating tape, 8 ……
Epoxy resin, 9 ... Terminal, 10 ... Drilling, 13
…… Support plate.

Claims (1)

[Scope of utility model registration request] 1. A tip of a tension member made of a carbon fiber reinforced plastic rod, which is formed by inserting a tip portion into a cylindrical fixture and fixing it with a grout material, and fixing the fixture with a grout material in the inner part of the drilling hole. Inserted in the cap and supported by the support plate of the tip cap, the heating coil is wound around the outer periphery of the upper part of the support plate protruding from the tip cap of the tension member through the insulating material, and the outer circumference of the coil is covered with the insulating material. A removable ground anchor characterized in that a heating coil terminal and a terminal formed at the end of the tension member are connected by a lead wire in a tip cap.