JPH0733665B2 - Anchor body construction method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anchor body driving method for driving permanent anchors or temporary anchors into the ground.

[0002]

2. Description of the Related Art When an anchor is placed in the ground, an excavation hole of a predetermined depth must first be drilled. Conventionally, however, it is the same as a casing pipe with a ring bit attached to the tip because of its excellent excavation efficiency. A double tube type boring rod is used which is inserted into the casing pipe and has an inner rod having an inner bit attached to the tip thereof. Then, when the boring rod has been dug to a predetermined depth, the boring rod is pulled up to insert an anchor wire into the excavation hole to inject grout.

However, the collapse of the hole wall occurs frequently in the excavation hole, and it has been extremely difficult to accurately arrange the anchor wire in the excavation hole. Therefore, when the anchor wire comes into contact with the surrounding hole wall, mud adheres to the anchor wire and impairs the adhesion between the anchor wire and the injected grout, or the function of the anchor wire is impaired by bending or damaging the anchor wire. There were many things.

In the case of a ground that can be dug only with a casing pipe, it is possible to use a construction method in which a casing is drilled, an anchor wire is inserted into the casing, and then grout is injected while the casing is removed. However, this construction method has a problem that the drilling speed is very slow and the efficiency is poor because the ground condition is severe and the center of the hole bottom cannot be drilled during the drilling.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-efficiency anchor body placing method which has a high drilling speed and facilitates insertion of an anchor wire.

[0006]

Means for Solving the Problems The gist of the present invention, which has solved the above problems, is to attach a ring bit having a receiving groove formed on its tip edge surface to the tip of a casing pipe of a boring rod and to insert an inner ring into the receiving groove of the ring bit. Drill a hole in the ground to a predetermined depth using a casing pipe with a bit inserted, insert an anchor wire inside the casing pipe and press the inner bit to separate the inner bit from the ring bit and leave it at the bottom of the hole. The anchor body placing method is characterized in that a grout is primarily injected into the excavation hole to form an anchor body having an inner bit as a core.

[0007]

In the anchor body placing method of the present invention, when excavating the ground, the ring bit at the tip of the casing pipe and the inner bit fitted in the receiving groove of the ring bit are used together for the boring, so the boring speed is Can be set large. At this time, the inner bit merely fits into the ring bit, but during the reciprocation, the inner bit receives the reaction force from the bottom of the hole, so that the inner bit is pressed by the ring bit and does not come off.

After the carving to the predetermined depth as described above, the anchor wire can be inserted with the casing pipe while preventing the hole wall from collapsing, so that the anchor wire can be extremely accurately contacted with the hole wall. Can be inserted.

When the anchor wire reaches the tip of the casing pipe, the inner bit can be easily separated from the ring bit by pressing the inner bit with the anchor wire. Then, if the inner bit is left at the bottom of the hole and primary injection of grout is carried out while pulling up the casing pipe, an anchor body having the inner bit as the core can be formed, so that the anchor wire and the anchor body, and the anchor body and the hole wall The combined state is also good.

[0010]

Embodiments will be described with reference to the following drawings. 1 is an explanatory view showing an embodiment, FIG. 2 is a bottom view showing an example of a bit, FIG. 3 is a sectional view taken along line AA of FIG. 2, and FIGS. 4 and 5 are perspective views showing an example of a bit.

In this embodiment, a ring bit 1 having a cemented carbide tip 2 planted therein is screwed into a casing pipe 3, and a cast iron inner bit 5 is placed in a receiving groove 4 formed in the tip edge surface of the ring bit 1. Has been inserted. Inner bit 5 has
A projecting portion 6 that is fitted into the receiving groove 4 of the ring bit 1 and a projecting portion 8 that is loosely fitted in the receiving groove 4 leaving a predetermined gap 7 are provided in a protruding manner. At the time of excavation, water is ejected through the air gap 7 and the ejection hole 9 formed in the inner bit 5 to advance. 10 is a waterway hole.

When the predetermined depth is reached, the anchor wire 11 is inserted into the casing pipe 3 and the inner bit 5 is pushed down to separate it from the ring bit 1. Then, while pulling up the casing pipe 3, primary injection of the grout 12 is performed to form the anchor body 13. Reference numeral 14 is a grout that has been subjected to secondary injection.

At this time, if a magnet or the like attracting each other is attached to the lower end of the anchor wire 11 and the central portion of the upper surface of the inner bit 5, the anchor wire 11 can be accurately arranged at the center of the excavation hole, and the subsequent process Therefore, even when the anchor wire 11 is tensioned, an accident of pulling out the anchor wire is unlikely to occur, which is convenient.

In the present invention, since the inner bit is buried in the ground, it is very difficult if the inner bit is made of inexpensive cast iron and the cemented carbide tip is implanted only in the ring bit as in this embodiment. It is practical.

The present invention is not limited to the above embodiment, but the shapes and fitting methods of the ring bit 15 and the inner bit 16 may be appropriate as shown in FIGS. Reference numeral 17 is a receiving groove.

[0016]

As described above, according to the present invention, since the ring bit and the inner bit are used together for excavation, the drilling speed can be set high and the efficiency is good. Further, since the anchor wire can be inserted while the casing pipe is inserted into the excavation hole, the anchor wire can be inserted with high accuracy at the center of the excavation hole and without the mud or the like sticking or bending. Furthermore, since the inner bit left on the bottom of the hole becomes the core of the anchor body and is embedded in the bottom of the hole, the strength as an anchor is also improved. In addition, the structure is simple and maintenance is simple compared to the double pipe type using a casing pipe and an inner rod.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example.

FIG. 2 is a bottom view showing an example of bits.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a perspective view showing an example of a bit.

FIG. 5 is a perspective view showing an example of a bit.

[Explanation of symbols]

 1 Ring Bit 2 Carbide Tip 3 Casing Pipe 4 Receiving Groove 5 Inner Bit 6 Projection Part 7 Void 8 Projection Part 9 Spouting Hole 10 Water Channel Hole 11 Anchor Wire 12 Grout 13 Anchor Body 14 Grout 15 Ring Bit 16 Inner Bit 17 Receiving Groove

Claims (1)

[Claims] 1. A ground pipe is fixed by using a casing pipe in which a ring bit having a receiving groove formed on a tip edge surface is attached to a casing pipe tip of a boring rod and an inner bit is fitted in the receiving groove of the ring bit. Drilling to a depth, inserting an anchor wire into the casing pipe and pressing the inner bit to separate the inner bit from the ring bit and leave it at the bottom of the hole. An anchor body placing method, which is characterized in that an anchor body having a core is formed.