JPH06248869A - Excavation method - Google Patents

Abstract

PURPOSE:To make it possible to use a casing pipe, which is light weight and low cost, and which is easy to join and disassemble and hence improve excavation speed in terms of a construction method which reinforces the inner peripheral surface of a excavation hole formed with an excavation tool with a casing pipe. CONSTITUTION:A casing tool 20 is inserted into a casting pipe 21 whose is similar to the casing tool. What is more, the casing pipe 21 is driven independently of the excavation tool 20 and rotate freely, centering on its axis. During excavation work, the excavation tool 20 excavates the ground by its rotary striking motion while the casing pipe 21 excavates the ground by its rotary motion. However, the casing pipe 21 is driven independently of the excavation tool 20, and what is more, it is in a non-contact state with the excavation tool 20. It is, therefore, possible to prevent a momentary stress concentration in a connected area between the casing pipes 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excavation method applied to various anchor works, various well works, various foundation pile hole works, etc., by using an excavating tool to excavate the ground, earth and sand, etc. The present invention relates to an excavation method in which a hole is covered with a pipe.

[0002]

2. Description of the Related Art As an excavation method used for various anchor constructions, there is a method of excavating while reinforcing the inner peripheral surface of an excavation hole formed by an excavation tool with a pipe for preventing collapse of the hole wall. Of the above construction methods, an example of a general excavation construction method by rotary excavation using an earth auger is shown in FIG.

In FIG. 4, reference numeral 1 is an earth auger used for excavation, around which an auger screw 2 having a spiral shape is formed, and the tip end portion is enlarged in diameter to form a head 3. The earth auger 1 is inserted into a casing pipe 4 having a cylindrical shape.

When the tip of the head 3 is pressed against the ground 5 and the earth auger 1 is rotated about its axis, the ground 5 is scraped off by the blade body 6 provided at the tip of the head 3 for excavation. Be seen. On the other hand, the casing pipe 4 is inserted along the hole wall into the excavation hole 7 formed as a result of excavation by the earth auger 1, and accordingly,
Since the hole wall is covered with the casing pipe 4, collapse of the hole wall is prevented. The earth and sand generated as a result of excavation are discharged upward by the auger screw 2.

After the excavation is completed, the earth auger 1 is pulled up from the excavation hole 7 and, if necessary, a reinforcing bar or the like is inserted into the casing pipe 4, and then the casing pipe 4 is pulled up from the excavation hole 7 and cement is put into the excavation hole 7. Etc. As a result, the reinforcing bars and the like are stably supported in the excavation hole 7 by the cement and the anchor work is completed.

On the other hand, when excavating by rotary impact excavation, for example, the excavating tools shown in FIGS. 5 to 7 are used.
In these figures, reference numeral 8 is a device that receives an impact force of a hammer (not shown) driven by compressed air and a rotational force of a hammer cylinder (not shown). , Two axial holes 8A and 8B are formed symmetrically with respect to the center of the device 8.

Each shaft hole 8A, 8B has a block shaft 9
A and 9B are rotatably mounted around the shafts and are fitted so as not to come off. The tip ends of the block shafts 9A and 9B are formed in a substantially semicircular shape having substantially the same diameter as the device 8, and the tip surfaces are Blocks 11A and 11B in which a large number of chips 10 are planted
Are provided with their straight end faces 12A, 12B facing each other.

Further, the block shafts 9A and 9B are arranged so that when the device 8 rotates in the excavating direction, the block shafts 9A and 11B.
One of the ends of each of the blocks 11 protrudes from the outer peripheral surface of the device 8 by a predetermined amount of excavation, and at that time, both blocks 11
The straight end faces 12A, 12B of A, 11B are eccentric from the center of the device 8 so as to abut each other.

Further, the excavating tool is slidably inserted in a casing pipe 13 having substantially the same diameter. Also,
At the inner circumference of the tip portion of the casing pipe 13, a reduced diameter pipe 15 that fits into the enlarged diameter portion 14 formed on the outer peripheral surface of the device 8.
However, they are integrally fixed by a method such as welding.

When the blocks 11A and 11B are projected from the tip of the casing pipe 13 and the device 8 is rotated in the excavating direction (direction of arrow X in FIG. 6), the blocks 11A and 1B are rotated.
1B is rotated about the block shafts 9A and 9B by the excavation resistance from the state shown in FIG. 6, and as a result, as shown in FIG. 7, the straight end faces 12A and 12 of the blocks 11A and 11B are rotated.
One end of B protrudes from the outer peripheral surface of the device 8 by a predetermined amount, and a part of the straight end surfaces 12A and 12B contact each other, so that the blocks 11A and 11B stop rotating.

Then, in the state shown in FIG. 7, the block 1
When the hammer and the hammer cylinder are operated while the tips of 1A and 11B are pressed against the ground, the rotational force and impact force of the hammer and the hammer cylinder are applied to the blocks 11A and 11 via the device 8.
B is transmitted to B, and blocks 11A and 11B move up and down and rotate in the direction of arrow X. As a result, the chip 10
Due to the local crushing and shear failure of the ground, the excavation is performed.

On the other hand, the impact force of the hammer is transmitted to the casing pipe 13 simultaneously with excavation due to the contact between the enlarged diameter portion 14 and the reduced diameter pipe 15 caused by the vertical movement, and the impact force and the own weight of the casing pipe 13 cause the impact force. , Casing pipe 1
The tip of 3 bites into the ground, and the casing pipe 13
Are pushed into the ground.

Further, the excavated earth and sand and the like are compressed air discharged when a hammer piston (not shown) falls in the hammer cylinder, and the compressed air is jetted from air holes 16A and 16B provided on the bottom surface of the device 8. By doing so, it moves from the tip of the excavating tool to the inside of the casing pipe 13 via a discharge groove (not shown) provided on the side surface of the device 8, and is further discharged in the proximal direction from there.

When the excavation is completed, the hammer cylinder is rotated in the direction opposite to the excavation direction. Then,
Due to the excavation resistance, the blocks 11A and 11B are rotated to the positions shown in FIG. 6 and reduced in diameter, and the excavation tool can slide in the casing pipe 13. Therefore, first, only the excavation tool is pulled up from the excavation hole. Next, if necessary, a reinforcing bar or the like is inserted into the casing pipe 13, and then the casing pipe 13 is pulled up from the excavation hole to fill the excavation hole with cement or the like, thereby completing the anchor work.

[0015]

By the way, in the excavation method using the casing pipes 4 and 13, the excavation hole 7
When it becomes deep, it is necessary to add the casing pipes 4 and 13. As a method of adding the casing pipes 4 and 13, the ends of the casing pipes 4 and 13 are vertically overlapped, and the overlapped portions are fixed by screws screwed from the outside in the radial direction, or the casing pipes 4 and 13 are fixed. A general method is to overlap the end faces of 13 and weld the end faces.

Here, among the conventional excavation methods described above, when excavating by rotary excavation, any method of screw fixing or welding can be used when the casing pipe 4 is replenished. However, the rotary excavation has a problem that the excavation speed is slow and the construction period is extended.

On the other hand, in the excavation by rotary impact excavation, although the excavation speed is high, since the impact force of the hammer is transmitted to the casing pipe 13 as described above, the impact force and the own weight of the casing pipe 13 are transmitted. As a result, the axial stress of the casing pipe 13 is momentarily concentrated on the connecting portion of the casing pipe 13 during excavation.

As a result, especially when the casing pipes 13 are connected by screws, the stress may be broken and broken due to the stress concentration. Therefore, the damage of the screw is prevented by increasing the mechanical strength of the connecting portion by increasing the thickness of the connecting portion and the diameter of the screw, but in this case, the total weight of the casing pipe 13 is increased. In addition to being heavy, there has been a problem that materials and costs required for manufacturing the casing pipe 13, the screw and the like are increased.

When the casing pipes 4 and 13 are connected by welding, the casing pipes 4 and 13 can be relatively lightweight, but the welding is troublesome, and when the casing pipes 4 and 13 are pulled up to the ground. Since the casing pipes 4, 13 are difficult to disassemble, the casing pipes 4, 1
It takes a lot of time to remove 3 and it is difficult to reuse the disassembled casing pipes 4 and 13.

The present invention has been made in view of the above circumstances. In the excavation method using a casing pipe, it is possible to use a casing pipe that is lightweight, inexpensive, easy to connect and disassemble, and improves excavation speed. The purpose is to let.

[0021]

According to the present invention, a lower end surface of a device that receives a rotational force has a substantially semicircular shape having a diameter substantially the same as that of the device, and a large number of blades are provided on the lower end surface. A pair of blocks and a block shaft that supports the block and is attached to the lower end surface of the device, and the position of the block shaft is set to one of the blocks when the device rotates in the excavation direction. All of the end portions of the device protrude from the outer peripheral surface of the device by a predetermined amount of excavation, and at that time, the straight end surfaces of the blocks are eccentric from the center of the device so that they are in contact with each other. At the same time, the outer periphery of the excavating tool is covered, and the rotary excavation is performed by the casing pipe that is driven independently of and in contact with the excavating tool. Also,
A blade may be provided at the lower end of the casing pipe.

[0022]

In the present invention, since the rotary impact excavation by the excavating tool and the rotary excavation by the casing pipe are performed independently of the excavating by the excavating tool,
During excavation, momentary stress concentration in the connecting part of the casing pipe is prevented.

[0023]

Embodiments of the present invention will now be described in more detail with reference to the drawings. The present invention is particularly characterized by the structure of the device and the casing pipe of the excavating tool shown in FIGS. 5 to 7 above. 5 to 7
The same reference numerals are given and their explanations are omitted.

A drilling tool 20 and a casing pipe 21 according to the present invention are shown in FIG. In FIG. 1, reference numeral 22 is a cylindrical device, and the blocks 11A, 1
1B is attached. Further, the drilling tool 20 is slidably inserted into a cylindrical casing pipe 21 having a diameter substantially the same as that of the drilling tool 20. The casing pipe 21 is driven by a motor (not shown), etc.
It is driven in a non-contact and independent manner, and is rotatable about its own axis at a constant speed, and an acute angle portion 23 is formed at the tip of the casing pipe 21 with its diameter gradually reduced in the tip direction. Has been done.

Next, an example in which an anchor construction is performed using this excavating tool will be described. FIG. 2 shows a situation of excavation using the excavation tool 20. In this case, in the state shown in FIG. 7, the blocks 11A and 11B receive the rotational force of the device 22 and the impact force of the hammer to move up and down and rotate in the arrow X direction in FIG. As a result, the chip 10 locally crushes and shears the ground 5, and excavation is performed.

On the other hand, the casing pipe 21 descends on the outer peripheral side of the excavation tool 20 while rotating at a constant speed during excavation, and the hole wall of the excavation hole 7 is accompanied by the casing pipe 21.
Since it is covered with, the collapse of the hole wall is prevented. In this case, the earth and sand remaining on the hole wall of the excavation hole 7 is scraped off by rotary excavation by the acute angle portion 23 formed at the lower end of the casing pipe 21. In addition, earth and sand generated by excavation,
The air is blown out from the air holes 16A and 16B provided on the lower end surface of the device 22, further moves from the tip of the drilling tool 20 to the inside of the casing pipe 21 through the discharge groove 24 provided on the side surface of the device 22, and further from there to the base end side. Is discharged to.

When the excavation hole 7 becomes deeper, the hammer cylinder and the casing pipe 21 are added accordingly. In this case, for example, an API hammer casing screw is used to connect the hammer cylinders, and screwing or welding is used to connect the casing pipe 21 as in the conventional excavation method.

In the excavation method of the present invention, since the excavation tool 20 and the casing pipe 21 are driven independently of each other without contact, the casing pipe 21 during excavation is completely independent of the excavation tool 20. Rotate. Moreover, since the casing pipe 21 rotates at a constant speed around its axis during excavation, momentary stress concentration does not occur at the connecting portion of the casing pipe 21.

Therefore, even if the casing pipe 21 is connected by a screw, the stress generated in the screw can be small, so that the stress concentration is not required even if the member forming the connecting portion is not made to have a structure having particularly high mechanical strength. The damage of the screw due to is prevented. As a result, the weight of the casing pipe 21 is reduced, and the materials and costs required for manufacturing the members forming the connecting portion are saved.

Further, in the excavation method of the present invention, since the excavation hole 7 is swiftly excavated by the rotary impact excavation by the excavation tool 20, the casing pipe 21 is preliminarily excavated by the blocks 11A and 11B. Only the peripheral surface will be excavated by rotation. Therefore, the excavation resistance received by the casing pipe 21 during excavation is small, and as a result, the excavation speed can be increased even though the rotary excavation is used in combination.

After the completion of excavation, when the hammer cylinder is rotated in the direction opposite to the predetermined direction, the blocks 11A and 11B rotate to the positions shown in FIG. 6 due to excavation resistance.
The diameter of the excavation tool 20 is reduced and can slide in the casing pipe 21. When the hammer cylinder is pulled in the base end direction in this state, only the excavation tool 20 is removed from the casing pipe 21 as shown in FIG.

Further, in the case of anchor work or the like, after the excavation tool 20 is pulled up, a reinforcing bar or the like is inserted into the casing pipe 21 remaining in the excavation hole 7. Then, a filler such as cement is flowed into the gap between the casing pipe 21 and the reinforcing bar or the like to replace the gap between the excavation hole 7 and the reinforcing rod with the filler, while the casing pipe 21 is moved to the excavation hole 7 or the like.
More to the ground. Then, the anchor work is completed by substituting the space between the excavation hole 7 and the reinforcing bar or the like with the filler. Here, when the casing pipes 21 are connected by screws, the casing pipes 21 pulled up
Of course, it is possible to reuse. Further, after the casing pipe 21 is completely pulled up from the excavation hole 7, the reinforcing bar or the filler may be filled again.

In the above embodiment, the case where the acute angle portion 23 is provided at the lower end of the casing pipe 21 has been described, but if necessary, a saw-shaped blade portion is provided along the circumference at the lower end of the casing pipe 21. By installing or implanting chips made of cemented carbide, casing pipe 2
It is also possible to improve the excavation capacity by 1.

[0034]

As described above, in the excavation method of the present invention, since stress concentration at the connecting portion of the casing pipes during excavation does not occur, the weight of the casing pipe can be reduced and the casing pipe Materials and costs for manufacturing are reduced. In addition, the casing pipes can be easily connected and disassembled, and the excavation speed can be improved, so that the excavation can be performed efficiently.

[Brief description of drawings]

FIG. 1 is a side view showing an example of the structure of a drilling tool used in a first embodiment of the present invention in a diameter-expanded state.

FIG. 2 is a diagram showing a situation of excavation using the excavation tool used in the first embodiment of the present invention.

FIG. 3 is a diagram showing a state in which a drilling tool used in the first embodiment of the present invention is pulled up from a drill hole.

FIG. 4 is a diagram showing a situation of excavation by rotary excavation, showing an example of a conventional excavation method.

FIG. 5 is a partial side sectional view showing an example of the structure of a drilling tool used in a conventional drilling method.

FIG. 6 is a front view in a reduced diameter state showing an example of the structure of a drilling tool used in a conventional drilling method.

FIG. 7 is a front view in a diameter-expanded state showing an example of the structure of a drilling tool used in a conventional drilling method.

[Explanation of symbols]

 1 Earth Auger 2 Auger Screw 3 Head 4, 13, 21 Casing Pipe 5 Ground 6 Blade 7 Drilling Hole 8, 22 Device 8A, 8B Shaft Hole 9A, 9B Block Shaft 10 Tip 11A, 11B Block 12A, 12B Straight End Face 14 Expanded part 15 Reduced tube 16A, 16B Air hole 20 Excavation tool 13 Sharp part 24 Discharge groove X Block rotation direction

Front page continued (72) Inventor Takeshi Hayashi 1528, Nakashinda, Yokoi, Kobe, Anpachi-gun, Gifu Prefecture Mitsubishi Materials Corporation Gifu Factory (72) Inventor Kenzo Nabei 633, Kazuki Tsukikuma, Hakata-ku, Fukuoka Address Toho Underground Machinery Co., Ltd.

Claims (2)

[Claims] 1. A pair of blocks in which a lower end surface of a device that receives a rotational force has a substantially semicircular shape having a diameter substantially the same as the diameter of the device, and a plurality of blades are provided on the lower end surface, and the block. And a block shaft attached to the lower end surface of the device to support the position of the block shaft when the device is rotated in the excavation direction. Of the excavation tool by a predetermined amount of excavation from the outer peripheral surface of the, and at the same time with the rotary impact excavation by the excavation tool eccentric from the center of the device so that the straight end surfaces of the blocks contact each other, The excavation method is characterized in that the rotary excavation is performed by a casing pipe that covers and is driven independently of and in contact with the excavation tool. 2. The excavation method according to claim 1, wherein the rotary excavation by the casing pipe is performed by a blade body provided at a lower end of the casing pipe.