JPH0571286A - Excavation method - Google Patents

Abstract

(57) [Abstract] [Purpose] Excavation is performed using a drilling tool that uses compressed air as a drive source, and a drilling method that reinforces the periphery of the drilling hole with a pipe enables drilling of a large diameter drilling hole. [Structure] A pipe 7 having a cylindrical shape, and air that is inserted into the pipe 7 and is equipped with expanding bits 5A and 5B that can expand the outer diameter of the pipe 7 or more at its tip, and discharges compressed air at its tip. The excavating tool 13 having the holes 12A and 12B installed therein, and the excavating equipment including the enlarged diameter portion 8 and the reduced diameter pipe 9 for restricting the movement of the excavating tool 13 toward the tip of the pipe 7 are provided. 5B is projected from the tip of the pipe 7 and is excavated with the diameter expanded, and the pipe 7 is inserted into the ground,
Compressed air is passed through the gap formed between the outer periphery of the pipe 7 and the wall of the hole to remove the earth and sand generated by the excavation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excavation method used for civil engineering work, construction foundation work, well making work, etc., and excavates formed by using an excavating tool driven by compressed air. The present invention relates to an excavation method in which an inner circumference of a hole is reinforced with a pipe for preventing collapse of a hole wall, and particularly relates to an excavation method for excavating a large-diameter hole.

[0002]

2. Description of the Related Art As a method of excavating a hole in the ground, for example, the following methods have been conventionally known. The process will be described with reference to FIGS.

FIG. 7 is a view showing a general excavation tool used in the conventional excavation method. This drilling tool is called a down-the-hole bit, and has a hammer (not shown) driven by compressed air and a bottom surface of the device 22 which receives a striking force and a rotating force of a hammer cylinder 21 and a diameter of the device 22. A bit 23 having a larger disk-like shape and having a large number of chips 4 planted on the tip surface is attached. Also, device 22 and bit 2
An air hole 24 penetrating the center of the hole 3 is formed.

FIG. 8 is a view showing a situation of excavation in the excavation method using the excavation tool. In this case, the impact force and the rotational force of the hammer and the hammer cylinder 21 cause the bit 23 to gradually impact and continuously strike the ground. As a result, the weight of the bit 23 and the action of the tip 4 locally affect the ground 10. Excavation is performed by causing crushing and shear failure. Further, the earth and sand generated by the excavation move upward from the gap γ formed between the hole wall of the excavation hole 11 formed as a result of the excavation and the side surface of the hammer cylinder 21 due to the pressure of the compressed air that is the driving source of the hammer. Is discharged to.

FIG. 9 shows a situation after completion of excavation in the above-mentioned conventional excavation method. Drilling tools for drilling holes 11
The tube 25 for covering the hole wall of the hole 11 and preventing the hole wall from collapsing after being pulled up from the hole 25.
Has been inserted. Here, the inner diameter of the drill hole 11 must be sufficiently larger than the outer diameter of the tube 25 so that the tube 25 can be inserted.

[0006]

Generally, in a drilling tool using compressed air as a driving source, it is preferable that the diameter of the air hole 24 is as large as possible in order to obtain compressed air having a high flow rate. The cylinder 21 needs to have a certain thickness or more. However, the hammer cylinder 21
There is a problem in that the load on excavation equipment including the excavation tool increases when the diameter of the excavation tool increases. Meanwhile, bit 2
Since a large number of chips 4 are planted at the tip of 3, the diameter of the air hole 24 is naturally limited.

Further, in the case of the above-mentioned conventional excavation method, if the bit 23 is replaced with a larger diameter for the purpose of enlarging the diameter of the excavation hole 11, the gap between the hole wall of the excavation hole 11 and the side surface of the hammer cylinder 21 is changed. The width of the gap γ formed in the
Increase by the increase in the caliber of. As a result, in the above-described conventional excavation method, the difference between the cross-sectional area of the gap γ and the cross-sectional area of the air hole 24 increases as the diameter of the excavation hole 11 increases, and the compressed air in the gap γ increases accordingly. The upward pressure and flow rate decrease. Then, when the flow velocity becomes equal to or lower than a value required to convey the earth and sand generated by excavation upward, the earth and sand cannot be discharged upward from the gap γ, and as a result, the excavation hole 11 has a large diameter. There was a problem that it became difficult to excavate.

There is also a problem that excessive excavation must be performed in order to make the inner diameter of the excavation hole 11 sufficiently larger than the outer diameter of the tube 25. Furthermore, the drill hole 11
Gap δ formed between the inner circumference of the tube and the outer circumference of the tube 25
Therefore, for the purpose of enhancing the stability of the tube 25 in the drill hole 11, there is a case where a work of filling the gap δ with a filler such as concrete is performed after the tube 25 is inserted, if necessary. .. All of these are problems not only in reducing workability but also in saving materials.

[0009]

DISCLOSURE OF THE INVENTION According to the present invention, an excavation tool having a bit at its tip is used for excavation, and the inner periphery of an excavation hole formed by excavation is reinforced with a cylindrical pipe for preventing hole wall collapse. In the excavation method

As the bit, a diameter-expanding bit capable of expanding the diameter of the pipe or more is used. An air hole for discharging compressed air is provided at the tip of the diameter-expanding bit, and the excavating tool is placed in the pipe. Inserting, the diameter-expanding bit is projected from the tip of the pipe, and the excavation is performed in a state where the diameter is expanded, and along with that, the pipe is inserted into the ground, and compressed air is ejected from the air hole. This is an excavation method in which air is passed through a gap formed between the outer periphery of the pipe and the inner periphery of the excavation hole to remove the earth and sand generated by excavation.

[0011]

According to the present invention, the earth and sand produced as a result of excavation are removed by the compressed air sent through the gap formed between the outer circumference of the pipe and the inner circumference of the excavation hole. Therefore, even if the diameter of the drill hole is enlarged, if the pipe is replaced with a pipe having a larger diameter to reduce the gap, the difference between the cross-sectional area of the air hole and the cross-sectional area of the gap is reduced. Can be made As a result, even when the diameter of the drill hole is enlarged, the pressure drop of the compressed air in the gap is small, and therefore, even for the drill hole having a large diameter,
It is possible to excavate using a drilling tool that uses compressed air as a drive source.

Further, since the inner diameter of the excavation hole is equal to or larger than the outer diameter of the pipe inserted in the excavation hole, and the gap between the inner diameter and the outer diameter is reduced, the excavation hole is excavated during excavation. The pipe inserted in can be used directly as the inner wall of the borehole. Therefore, the excavation process is simplified and the material required for excavation is saved.

[0013]

Embodiments of the present invention will now be described in more detail with reference to the drawings.

Examples of excavation equipment used in the present invention are shown in FIGS. This excavation equipment includes an excavation tool 13 that actually excavates, a pipe 7 that covers the periphery of the excavation tool 13,
It comprises a diameter-reducing pipe 9 for restricting the movement of the drilling tool 13 toward the tip of the pipe 7.

Of these, the excavation tool 13 is mounted on the bottom surface of the device 2 which receives the impact force of a hammer (not shown) driven by compressed air and the rotational force of the hammer cylinder 1, with respect to the center of the device 2. Two shaft holes 2A and 2B in point symmetry
And the bit shafts 3A, 3
B is rotatably mounted around the axis and is fitted in such a manner that it does not come off and has a substantially semicircular shape with a diameter substantially the same as the diameter of the device 2 at the tip end of each bit shaft 3A, 3B, and a large number of tips. Expanding bits 5A and 5B in which tips 4 are planted are provided with their straight end surfaces 6A and 6B facing each other, and bit shafts 3A and 3B.
When the device 2 is rotated in a predetermined direction, one end of each of the expanded diameter bits 5A and 5B both protrudes from the outer peripheral surface of the pipe 7 by a predetermined amount of excavation, and at that time, both of the bits are directly moved. The end faces 6A, 6B are eccentric from the center of the device 2 so that they come into contact with each other.

The pipe 7 has a cylindrical shape, and the excavation tool 13 is slidably inserted therein. Then, on the inner circumference of the tip portion of the pipe 7, a diameter-reducing tube 9 that fits the diameter-increasing portion 8 formed on the outer peripheral surface of the device 2 is integrally fixed by welding or another method.

Next, the excavation method in the present invention using the above-mentioned excavation equipment will be described.

FIG. 4 shows a situation of excavation in the above example. In this case, when the device 2 is rotated in the predetermined direction (arrow X in FIG. 2) by the hammer cylinder 1 in a state in which the diameter expansion bits 5A and 5B are projected from the tip of the pipe 7, the diameter expansion bits 5A and 5B are From the state as shown in FIG. 2, the bit shafts 3A, 3B are rotated about their axes by excavation resistance, and as a result, as shown in FIG.
One end of the straight end surfaces 6A, 6B of B protrudes from the outer peripheral surface of the pipe 7 by a predetermined amount, and parts of the straight end surfaces 6A, 6B abut each other, and the rotation of the diameter-enlarging bits 5A, 5B stops. .. In this state, when the impact force of the hammer and the rotational force of the device 2 are applied to the diameter expansion bits 5A and 5B, the diameter expansion bits 5A and 5B rotate with the vertical movement, and
Due to the weight of A and 5B and the action of the tip 4, the ground 10 is locally crushed and sheared, and excavation is performed.

On the other hand, the impact force of the hammer is transmitted to the pipe 7 at the same time as the excavation due to the contact between the enlarged diameter portion 8 and the reduced diameter pipe 9 caused by the vertical movement, and the impact force and the weight of the pipe 7 cause the pipe to move. 7 The tip is pushed into the ground 10. here,
Since the reduced diameter pipe 9 is located below the enlarged diameter portion 8, the impact force is transmitted only in the direction of pushing the pipe 7 into the ground 10,
As a result, collapse of the hole wall due to water or the like leaching from the hole wall of the excavation hole 11 is effectively prevented.

The earth and sand produced as a result of the excavation is discharged from the air holes 12A and 12B provided on the bottom surface of the device 2 as the compressed air discharged when the hammer piston (not shown) falls inside the hammer cylinder 1. By doing so, it is separated from the tip of the excavation tool, and is further discharged upward from the gap α formed between the outer periphery of the pipe 7 and the excavation hole 11.

Here, in the present invention, the diameter of the pipe 7 can be exchanged according to the inner diameter of the excavation hole 11. Therefore, even when the width of the gap β formed between the hole wall of the drill hole 11 and the side surface of the hammer cylinder 1 increases as the drill hole 11 expands, the pipe 7 is replaced with a pipe having a larger diameter. Then, if the gap α formed between the outer periphery of the pipe 7 and the excavation hole 11 is reduced, the air holes 12A, 12B
It is possible to reduce the difference between the cross-sectional area of and the cross-sectional area of the gap α. As a result, even when the diameter of the excavation hole 11 is enlarged, the pressure drop of the compressed air in the gap α is small,
Therefore, it is possible to excavate a large-diameter excavation hole 11 using an excavation tool driven by compressed air.

FIG. 5 shows the situation at the end of excavation in the above example. In this case, the hammer cylinder 1 is rotated in the direction opposite to the predetermined direction, and the diameter expansion bits 5A, 5B are rotated.
2 to the position shown in FIG. 2, the drilling tool 13 can slide in the pipe 7. Therefore, if the hammer cylinder 1 is pulled upward, as shown in FIG. Can be pulled upwards from.

On the other hand, as described above, the inner diameter of the excavation hole 11 formed by excavation and the pipe 7 inserted into the excavation hole 11
Since the gap α between the outer diameter of
The stability of the pipe 7 in 1 is very high. Therefore, the pipe 7 can be directly used as the inner wall of the drill hole 11. Further, it is of course possible to pull out the pipe 7 from the digging pit 11 after the digging is completed.

In order to reduce the load that the bit receives during excavation, the number of diametrically expandable bits may be divided into three or more, and if necessary, at the tip of the hammer cylinder 1, the above-mentioned example may be used. Expanding bit 5 that can be expanded freely
Instead of A, 5B, a conventional drilling tool, such as a down-the-hole bit, can be attached for further drilling.

[0025]

As described above, according to the present invention,
By the compressed air sent to the gap formed between the outer circumference of the pipe and the inner circumference of the drill hole, in order to remove the sediment resulting from the drilling, even when the diameter of the drill hole is increased, By replacing the pipe with a pipe having a larger diameter to reduce the gap, it was possible to reduce the difference between the cross-sectional area of the air hole and the cross-sectional area of the gap. As a result, even when the inner diameter of the drill hole is enlarged, the pressure drop of the compressed air in the gap is small, so that the drilling tool using the compressed air as the driving source is used for the drill hole having a large diameter. Became possible.

Further, since the inner diameter of the drill hole is equal to or larger than the outer diameter of the pipe inserted into the drill hole, and the difference between the inner diameter and the outer diameter is reduced, the drill hole is used at the time of drilling. It was possible to directly use the pipe inserted in the inner wall of the drill hole. Therefore, the excavation process was simplified and the materials required for excavation were saved.

[Brief description of drawings]

FIG. 1 is a partial side sectional view of excavation equipment used in a first embodiment of the present invention.

FIG. 2 is a plan view showing a state in which the diameter-expanding bit is reduced in the excavation equipment used in the first embodiment of the present invention.

FIG. 3 is a plan view showing a state in which the diameter-expanding bit is expanded in the excavation equipment used in the first embodiment of the present invention.

FIG. 4 is a partial side cross-sectional view of excavation equipment showing a situation of excavation work in the first embodiment of the present invention.

FIG. 5 is a partial side cross-sectional view of the excavation equipment showing the situation at the end of excavation in the first embodiment of the present invention.

FIG. 6 is a partial side sectional view of the excavating equipment showing the state of the excavating tool lifting operation in the first embodiment of the present invention.

FIG. 7 is a partial side sectional view of a drilling tool used in a conventional drilling method.

FIG. 8 is a diagram showing a situation of excavation work in the conventional excavation method.

FIG. 9 is a side cross-sectional view of an excavation pit showing a situation after completion of excavation in a conventional excavation method.

[Explanation of symbols]

1, 21 Hammer cylinder 2, 22 Device 2A, 2B Shaft hole 3A, 3B Bit shaft 4 Tip 5A, 5B Expanding bit 6A, 6B Straight end face 7 Pipe 8 Expanding part 9 Contracting pipe 10 Ground 11 Drilling hole 12A, 12B, 24 Air hole 13 Drilling tool 23 Bit 25 Tube α Gap formed between hole wall of drilling hole and side surface of pipe inserted into drilling hole δ Hole wall of drilling hole and inserted into drilling hole Gap formed between the side wall of the tube and the side wall of the β drill hole and the side wall of the device inserted in the drill hole γ Hole wall of the drill hole and the hole wall of the drill hole Gap formed between the side of the hammer cylinder and

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoneo Hiwasa 1528, Nakashinden, Yokoi, Kobe-shi, Anpachi-gun, Gifu Prefecture Mitsubishi Materials Corporation Gifu Factory

Claims (2)

[Claims] 1. A drilling method in which drilling is performed using a drilling tool having a bit at the tip, and the inner circumference of a drilled hole formed by drilling is reinforced with a cylindrical pipe for preventing hole wall collapse, A diameter-expanding bit capable of expanding the diameter of the pipe or more is used, an air hole for discharging compressed air is provided at the tip of the diameter-expanding bit, and the drilling tool is inserted into the pipe to expand the diameter. The excavation is performed with the bit protruding from the tip of the pipe and expanded in diameter, and along with that, the pipe is inserted into the ground, and compressed air is ejected from the air hole, and the compressed air is supplied to the outer periphery of the pipe. The excavation method is characterized in that the sand and sand generated by excavation are removed by sending it through a gap formed between the inner periphery of the excavation hole and the inner periphery of the excavation hole. 2. The excavation method according to claim 1, wherein after the completion of excavation, the diameter-enlarging bit is reduced in diameter to pull up only the excavation tool from the excavation hole.