JPH10266203A - Construction method of anchor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily extend an anchor by fitting a packer device to the outer periphery of an anchor body, and after inserting the body in a drilled hole in the contracted state of a packer, expanding the packer to anchor the body. SOLUTION: A packer 3 expandable/contractible by air pressure or the like is fitted to the outer periphery of a hollow pipe 1. The pipe 1 is then inserted into the bottom of a drilled hole in the contracted state of the packer 3. Air pressure or the like is supplied to the packer 3 through a pressure pipe 4 to expand the packer 3 so as to stick closely to the hole wall, thus anchoring the tip of the pipe 1. A pressure plate 5, a nut 6, and the like are fitted to the tail end of the pipe 1 exposed to the outside of the hole. At the time of adding an anchor, a drilling bit 2 is inserted from the tail end of the pipe 1 to drill the tip of the anchor hole. A new pipe 1 is then connected to the tail end of the pipe 1. After contracting the packer 3, the pipe 1 is pushed into the hole, and the packer 3 is expanded. Whereby the anchor can be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for installing an anchor.

[0002]

2. Description of the Related Art In a conventional anchor, a steel rod is inserted into a drilled hole, and the tip of the steel rod is hardened and fixed with a mortar or the like. Using the fixing force as a supporting force, a reaction force is applied to the exposed tail end portion and used as an anchor.

[0003]

Since the anchor is fixed at the tip at the bottom of the hole, if the conventional anchor cannot secure the reaction force after the anchoring, or if the anchoring force is insufficient, the anchoring force of the anchor is reduced. It was not possible to augment.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. An anchor installation method capable of further extending a hole in a fixed anchor by drilling the inside of the hole. The purpose is to provide.

[0005]

In order to achieve the above-mentioned object, a method for installing an anchor according to the present invention uses a hollow pipe as an anchor body, and an inflatable and contractible packer is provided on the outer periphery of the anchor body. An anchor installation method is characterized in that the device is attached, the packer is contracted, and the anchor body is inserted into the drilled hole, and after the insertion, the packer is expanded to fix the anchor body.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

<A> Anchor body. The construction method of the present invention is characterized in that the hollow pipe 1 is used as the anchor body. Hollow pipe 1
Therefore, drill bit 2 from the tail end exposed to the outside
Etc. can be inserted. A packer 3 that can expand and contract at one or more locations is attached to the outer periphery of the hollow pipe 1 as an anchor body. The packer 3 uses a bag-like body that can be expanded and contracted by air pressure, hydraulic pressure, and water pressure. Alternatively, a ring-shaped body that can be expanded or contracted in diameter by being externally rotated, compressed or stretched is used. Alternatively, a mechanical pantograph structure or a supporting gripper structure may be employed. Pressurizing pipe 4 for supplying air pressure
Extends to the outside of the hole. Further, the tail end of the hollow pipe 1 is threaded. The hollow pipe 1 can be extended by sequentially connecting using these screws.

<B> Anchor anchoring. To fix the anchor, the hollow pipe 1 is inserted into the drilled hole while the packer 3 is kept contracted. When the packer 3 is expanded after being inserted to the bottom of the hole, the packer 3 comes into close contact with the hole wall, and the hollow pipe 1 is fixed. After the end of the hollow pipe 1 is fixed, the reaction force plate 5, the nut 6, and the like are attached to the tail end exposed outside the hole and fixed (FIG. 5). Alternatively, the center hole jack 10, the reaction force plate 5, the nut 6, and the like are attached and fixed (FIG. 6).
The packer 3 pressurizing pipe 4 passes through, for example, the inside of the reaction force plate 5 and is drawn out from a position where the nut 6 does not contact.

<C> When an anchor needs to be added. The fixing of the hollow pipe 1 as an anchor is completed by the above steps. Generally, there is no problem in this state, but in reality, the following problem may occur. When the bearing capacity of the anchor cannot be secured afterwards. When greater anchor capacity is required. In a system in which an anchor is used as a reaction body to cut and excavate rock or the like toward the anchoring portion of the anchor, when the excavation proceeds to a length that causes insufficient anchoring force, and the anchor length is insufficient.

<D> Additional drilling. In such a case, the method of the present invention uses the hollow pipe 1
The drill bit 2 is inserted from the tail end of. This drill bit 2
Is attached to the tip of the rod 7, but a hole-expanding type is adopted. As a hole-expanding mechanism, for example, a known hole-expanding bit such as a type in which an eccentric short pillar is interposed at the tip and an eccentric portion protrudes in the circumferential direction by rotating the rod 7 in the opposite direction so that a large diameter can be drilled. Use 2. When the tip of the anchor hole is additionally drilled with such a drill bit 2, a hole having a diameter larger than the outer diameter of the hollow pipe 1 can be drilled.

<E> Additional insertion. Fixation. After drilling in advance, a new hollow pipe 1 is connected to the tail end of the hollow pipe 1 using a screw. Next, the packer 3 is contracted. Then, since the fixing between the hollow pipe 1 and the hole wall is opened, the hollow pipe 1 is pushed into the deep portion of the hole according to the extended length. After inserting to the bottom of the additionally drilled hole, the packer 3 is expanded again. A packer 3 is provided on the outer periphery of the hollow pipe 1 to be newly added to the tail end of the old pipe 1.
Can be attached in a contracted state. By expanding the packer 3 again, the hollow pipe 1 can be fixed at a deeper portion, and a larger fixing force can be obtained.

[0012]

[Effects of the Invention] Since the method of installing an anchor according to the present invention is as described above, the following effects can be obtained. <A> With the conventional anchor, even if a longer anchor is required at the same position after fixing, there is no other method than dismantling and removing the old anchor. In that case, it will be anchorless for a long time from the removal of the old anchor until the reaction force is obtained by the new anchor,
Dangerous conditions could have occurred. <B> On the other hand, according to the method of the present invention, it is possible to keep taking a reaction force during drilling. The non-anchor state is only for the time of shrinking the packer 3 and expanding the packer 3 again, so that the processing can be performed in a very short time and safe construction is possible. <C> The anchor holes can be additionally drilled, and the operation of additionally inserting the anchors can be repeated, so that the anchors can be advanced like a scale. So, for example, tunnel face,
If the anchor of the present invention is fixed on other excavated surfaces,
In parallel with the excavation of the face, the anchor can be advanced like a scale. <D> The method of the present invention can also be used as a reaction body of a tunnel machine. That is, a method in which an anchor setting hole is opened in front of the excavator, an anchor is set into the ground in front of the setting hole, and the excavator is advanced using the anchor as a reaction force. In that case, the work in the large number of casting holes is divided into two cycles. In half of the casting holes, the excavator is attracted by taking a reaction force to the already installed anchor. From the remaining half of the holes, drilling and driving of anchors in the next cycle are performed. In this case, the anchor is always anchored in half of the anchor placing holes, and it is possible to continuously advance.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an embodiment of a method for installing an anchor according to the present invention.

FIG. 2 is an explanatory view of an embodiment of a method for installing an anchor.

FIG. 3 is an explanatory view of an embodiment of a method for installing an anchor.

FIG. 4 is an explanatory view of an embodiment of a method for installing an anchor.

FIG. 5 is an explanatory view of a state where an anchor is fixed.

FIG. 6 is an explanatory view of a state where an anchor is fixed.

Claims (2)

[Claims] 1. A hollow pipe is used as an anchor body, and an expandable / contractible packer device is attached to the outer periphery of the anchor body, and the anchor body is inserted into a drilled hole while the packer is contracted. Anchor construction method by inflating the packer and fixing the anchor body 2. Using a hollow pipe anchor body, insert a drill bit from the tail end of the hollow pipe into the anchor fixed in the hole by expanding the packer, and additionally drill an anchor hole with the drill bit. After drilling, connect a new hollow pipe to the tail end of the hollow pipe, shrink the packer and insert the anchor body further into the deep part of the hole, expand the packer after additional insertion, and anchor at the deeper part. Anchor construction method for fixing the main body