JP2557035B2 - Unbonding method for anchor cable - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground anchor cable which is buried in the ground to fix a structure or the like, and particularly to allow free extension of the anchor cable when prestressing force is applied. The present invention relates to a method of processing into unbonded.

[0002]

2. Description of the Related Art In a ground anchor for burying a structure or the like on the ground by burying it in the ground, a plurality of steel stranded wires or the like are used as anchor cables, which are inserted into a drilled hole in the ground. A hardening material such as cement milk is injected into the drilled hole, and a tip of the anchor cable, that is, a portion located at the back of the drilled hole is used as a fixing long portion to which the hardening material is attached and fixed. The portion above the ground is an unbonded portion, that is, a portion that does not adhere to the hardening material, and is a free length portion in which the cable freely extends when a prestressing force is applied to the cable. In the case of unbonding the free length portion, as shown in FIG. 5, each cable a is generally passed through a separate unbonded sheath b such as polyethylene.

However, passing each cable a through a separate unbonded sheath is cumbersome and expensive, and requires a long delivery time. Also sheath b
Has a thin wall thickness of about 1.0 to 1.2 mm, and in order to protect the cable, the portion passed through the unbonded sheath b needs to be passed through a thicker free length sheath c. A plurality of anchor cables a passed through the unbonded sheath b are collectively passed through the free length sheath c, but the thickness of the unbonded sheath b of the plurality of cables a occupies a considerable space as a whole. The diameter of the free length sheath c was considerably large. The diameter of the drilled hole into which the free length sheath c is inserted must be increased by that much, and even if the drilled hole diameter is increased by 5 mm, the construction becomes large, which is a cause of high construction cost.

[0004]

For this reason, the free length portion of the plurality of anchor cables has a wall thickness of 3.5 to 8.
It is also adopted to reduce the diameter of the anchor by passing it through a single unbonded sheath of about mm. The gap between the cables of the unbonded sheath is filled with anticorrosive oil to prevent water from entering and also to prevent the cables from rubbing against each other. In order to fill the rust preventive oil into the unbonded sheath, the rust preventive oil that has been warmed and fluidized was poured from the end of the sheath using a funnel or the like.

However, the free length is several tens of meters, and the heated rust-preventive oil touches the sheath and the cable to cool and harden during the process, making it impossible to completely fill the entire length of the sheath. For this reason, a hole was made in the middle of the unbonded sheath, and rust preventive oil was poured again from here, but it was not preferable to make a hole in the sheath because it would cause the infiltration of water and the like. For this purpose, as shown in FIG. 6, there is also a method of immersing the unbonded sheath d in the rust preventive oil f contained in the box-shaped oil tank e and immersing the oil f in the unbonded sheath d. Even if the sheath d lay in the oil f, the air in the sheath d was not sufficiently escaped, and it was difficult to fill the oil f. Further, the oil tank e was flat, and it was difficult to take up space and warm it to fluidize the oil f.

The present invention has been made to solve the above problems, and is an unbonding method for an anchor cable that can be unbonded by filling the entire length of the free length sheath with rust preventive oil without any voids. The purpose is to provide.

[0007]

According to the method for unbonding an anchor cable according to the present invention, a part of a plurality of cables is used as a free length portion, and the cables are aligned so that the free length portion is in an unbonded sheath. Pass through. As the anchor cable, stranded steel wire or steel wire can be used, and as the unbonded sheath, a synthetic resin sheath having a wall thickness of about 3.5 to 8 mm is adopted. The unbonded sheath passing through the plurality of cables is spirally wound up. Dip this unbonded sheath in an oil tank. The oil tank has a certain depth and contains warm oil. As a means for warming the oil, heating may be performed from below the oil tank, or a heater may be placed in the oil tank to heat the oil. At this time, the fixing length portion that is exposed from the unbonded sheath of the anchor cable is projected from the oil. The other end of the unbonded sheath is located on the bottom side of the oil tank. The pressure of the oil causes the oil to infiltrate from the end of the unbonded sheath on the bottom side of the oil, and the air escapes from the end on the fixing long side side, so that the sheath is filled with the oil. Pull up with both ends of the unbonded sheath positioned above. Specifically, it is lifted from the oil by lifting it with a rope. Allows the antirust oil in the unbonded sheath to cool and harden.

After air is released from the unhonded sheath in the oil tank and filled with oil, the spirally wound unbonded sheath is rotated in the oil tank so that the unbonded sheath is laid down sideways. It is also possible to position the above and then pull up.

[0009]

[Function] Since the unbonded sheath is immersed in the oil tank of the deep tank, the oil in the sheath is satisfactorily released and the oil is filled in the sheath. Since the sheath is rolled up and placed in the deep oil tank, the space occupied by the oil tank can be small. It is easy to heat oil.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the embodiments shown in the drawings. In the figure, reference numeral 1 denotes an unbonded sheath made of synthetic resin, and a plurality of steel stranded wires, which are anchor cables 2, are aligned and inserted into the unbonded sheath 1. A part of the anchor cable 2 is exposed from the unbonded sheath 1 to form a fixing long portion 3. The unbonded sheath 1 is wound up in a spiral shape. It is not necessary to wind up the fixing long portion 3 which has been exposed.

In the figure, reference numeral 4 denotes an oil tank, which has a bathtub shape with a deeper depth, and is heated by a heater 5 from below the oil tank 4 to fluidize the oil 6 inside. The unbonded sheath 1 is dipped in the oil tank 4. In the embodiment, the unbonded sheath 1 wound by the rope 7 is hung by both ends of the unbonded sheath 1 and immersed in the oil 6. One end of the unbonded sheath 1 is located on the bottom side of the oil tank 4, the other end of the fixing long part 3 is located near the surface layer of the oil 6, and the fixing long part 3 is not immersed in the oil 6. The pressure of the oil 6 causes the oil 6 to infiltrate from the end of the unbonded sheath 1 located on the bottom side of the oil tank 4, and the air escapes from the end of the fixing long portion 3 to fill the oil 6.

In this state, the unbonded sheath 1 is rotated in the oil tank 4 so that the unbonded sheath 1 is laid sideways, and both ends of the unbonded sheath 1 are positioned so as to be located above and lifted. Leave it in this state for a while and let it cool naturally. Remove the rope 7 after the oil 6 hardens and cannot flow down. When the anchor cable 2 thus unbonded is used, the fixing length part 3 is passed through a fixing sheath made of stainless steel or the like, and the unbond sheath 1 is passed through a free length part sheath made of synthetic resin. 1 may be used as it is as a free length sheath.

[0013]

The present invention has the above-mentioned structure and can obtain the following effects. Since the anchor cable is spirally wound and immersed in a deep oil tank, the space occupied by the oil tank can be reduced, and processing can be performed even in an environment with little space on site. Since a plurality of anchor cables are passed through the unbonded sheath together, the diameter of the sheath can be reduced, the diameter of the drilled hole can be reduced, and the excavation cost can be reduced. The unbonded sheath is dipped in an oil bath of a deep tank, and one end is located on the bottom side to let out the air in the sheath, so that the sheath is well filled with oil. Since the oil is heated and fluidized, it does not cool and solidify inside the sheath, it is not necessary to make a hole in the middle of the sheath to pour it, and the sheath is not damaged. The oil tank is a deep tank, does not require a large space, and can easily heat the oil. After the sheath is filled with oil, the sheath is positioned above both ends of the sheath and is pulled up from the oil for cooling, so that the oil does not spill and the filling of the sheath with oil is not impaired.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an implementation state of an unbonding processing method.

FIG. 2 is an explanatory diagram showing a state in which an unbonded sheath is rotated in an oil tank.

FIG. 3 is a side view of an unbonded sheath through an anchor cable.

FIG. 4 is a cross-sectional view of an unbonded sheath.

FIG. 5 is a cross-sectional view of a conventional unbonded cable.

FIG. 6 is an explanatory diagram showing a state in which an unbonded sheath is immersed in an oil tank.

[Explanation of symbols]

 1 Unbonded sheath 2 Anchor cable 3 Fixing part 4 Oil tank 5 Heater 6 Oil 7 Rope

Claims (2)

(57) [Claims] 1. A part of a plurality of cables is used as a free length part, and the free length part is inserted into an unbonded sheath made of synthetic resin, and the free length part is spirally wound and heated to be fluidized. Immersed in a deep tank containing rust-preventing oil, the fixing long part that came out of the unbonded sheath and sticks out is projected from the rust-preventing oil, and the other end is located at the bottom of the oil tank. Anchor that cools and solidifies the anti-corrosion oil in the unbonded sheath by pulling out from the anti-bonding oil with both ends of the unbonded sheath positioned above after the air escapes from the sheath and is filled with the anti-corrosion oil. Cable unbonding method. 2. A part of a plurality of cables is used as a free length portion, the free length portion is inserted into an unbonded sheath made of synthetic resin, and the free length portion is spirally wound and heated to be fluidized. Immersed in a deep tank containing rust-preventing oil, stick out the fixing long part that came out from the unbond sheath and stick out from the rust-preventing oil, and place the other end at the bottom of the oil tank and unbond it. After air escapes from the sheath and the anti-corrosion oil is filled, the anchor cable is laid sideways in the anti-corrosion oil and both ends of the unbonded sheath are positioned upwards, and then pulled out from the anti-corrosion oil. Unbonding method of the anchor cable that cools and solidifies the rust preventive oil inside.