JP2006283516A - Excavation tool and excavation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expansion/contraction type excavation tool which forms an excavation hole of a large diameter stably and efficiently, easy to handle and is low in the manufacturing cost, and also to provide an excavation method for forming the excavation hole of the large diameter and burying a casing pipe of a large diameter. <P>SOLUTION: The excavation tool 21 arranged at a front end of a drilling rod is provided with a plurality of bit units 22 on a front end side of the excavation tool 21. Each of the bit units 22 includes: a bit head 51 having a chip fixing part 52; and a device 31 having a supporting part 35 for supporting the bit head 51 to be rotatable around an axial line L eccentric from a rotary shaft O of the drilling rod, and having a mounting part 32 on the rear end side for mounting each of the bit units 22 on an air hammer. A bit part 23 is formed on a front end side of the excavation tool 21 by a plurality of bit heads 51 of the bit units 22. By the rotation of each of the bit heads 51 around the axial line L, the outer diameter of the bit part 23 is expanded or contracted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an excavation tool used when excavating ground and earth and sand and various excavation methods using the excavation tool in various types of anchor construction, various drilling works, and various foundation pile hole constructions.

As an excavation tool for excavating the ground and earth and sand, a tool having a bit portion provided with a plurality of chips made of a hard material such as cemented carbide and an air hammer that strikes the bit portion has been proposed (Patent Documents 1 to 3). 3).
4 to 6 show an example of a conventional excavation tool. As shown in FIG. 4, the excavation tool 1 has a multi-stage cylindrical shape, and a device portion 2 that receives a blow of an air hammer E (not shown) and a tip side of the device portion 2 (lower side in FIG. 4). And three bit heads 6 arranged in the same manner.

On the rear end side (upper side in FIG. 4) of the device portion 2, a shaft-shaped small diameter portion having a small step diameter is formed, and this small diameter portion serves as a mounting portion 3 for an air hammer E (not shown). Further, a concave portion 4 having a circular cross section extending along the axis L of the cylinder formed by the device unit 2 is formed on the distal end surface of the device unit 2, as shown in FIGS. 5 and 6, and the axis L of the column formed by the device unit 2. Are formed in three rotational symmetry about the center.
In addition, the device portion 2 is provided with a columnar retaining pin 5 that is inserted from the outer peripheral surface of the device portion 2 and is disposed so as to penetrate a part of the outer peripheral portion of the recess 4.

  The rear end side (upper side in FIG. 4) of the bit head 6 is a substantially cylindrical mounting shaft portion 7, and the front end side (lower side in FIG. 4) is a substantially fan-shaped chip fixing portion 9. As shown in FIG. 4, the mounting shaft portion 7 is formed with a ring-shaped groove 8 having a bottom surface with a concave curved surface. The bottom surface of the ring-shaped groove 8 and a retaining pin 5 formed in a column shape are formed. The outer peripheral surface is slidable. A plurality of button-like chips 10 made of a hard material such as cemented carbide are fixed to the tip surface of the chip fixing portion 9.

The mounting shaft portion 7 of the bit head 6 is fitted into the recess 4 of the device portion 2, and the retaining pin 5 is inserted so as to be slidable on the bottom surface of the ring-shaped groove 8, so that the bit head 6 is connected to the axis of the mounting shaft portion 7. Is fixed so as not to move in the axial direction of the mounting shaft portion 7.
Then, bit heads 6 each having a fan-shaped flat chip fixing portion 9 are attached to the three concave portions 4, and the bit portion 11 is formed on the tip surface of the excavation tool 1 by these three bit heads 6.

  When the excavation tool 1 configured as described above is rotated in the tool rotation direction X and sent to the drilling material in the drilling direction, the three bit heads 6 are each caused by excavation resistance from the drilling material. As shown in FIG. 5, a part of the bit head 6 protrudes from the outer peripheral surface of the device portion 2 and the bit portion 11 is expanded in diameter. By performing excavation in the drilling direction in this state, an excavation hole having a diameter one step larger than the outer diameter of the device unit 2 is formed.

  On the other hand, when the excavation tool 1 is rotated in the direction opposite to the tool rotation direction X (rotation direction Y in FIG. 6), the three bit heads 6 change the axis of each mounting shaft portion 7 by frictional resistance with the material to be excavated. As shown in FIG. 6, the bit portion 11 is all reduced in diameter so as to be located inside the outer diameter of the device portion 2. In this state, the excavation tool 1 can be taken out by moving the excavation tool 1 to the side opposite to the drilling direction.

If the above excavation tool 1 is used, the diameter of the bit portion 11 is expanded during the excavation and protrudes outward from the outer peripheral surface of the device portion 2, thereby forming an excavation hole that is one step larger in diameter than the outer diameter of the device portion 2. The casing pipe is stood up, and when the excavation hole is formed up to a predetermined position and the casing pipe is embedded, the bit portion 11 is reduced in diameter and extracted through the inside of the casing pipe to the opposite side of the drilling direction. The excavation tool 1 can be recovered while being embedded in the excavation hole.
Japanese Patent No. 2599846 JP 2004-183471 A Japanese Utility Model Publication No. 63-23508

  By the way, when the excavation tool 1 (hereinafter referred to as an expansion / contraction excavation tool) capable of expanding / contracting the bit portion 11 is used to form a large-diameter excavation hole exceeding 800 mm, for example, the diameter of the excavation hole is set. It is necessary to prepare a corresponding large-diameter air hammer E. Such a large-diameter air hammer E is designed on the assumption of using a drilling tool (hereinafter referred to as a fixed drilling tool) whose bit portion does not expand or contract. Only what is provided is provided. Here, the expansion / contraction type excavation tool 1 is provided with the device portion 2 as described above, and the weight is greatly increased as compared with a fixed excavation tool that forms an excavation hole having the same diameter. Therefore, when the expansion / contraction excavation tool 1 is mounted on the air hammer E having a large diameter specification on the assumption that the fixed excavation tool is used, the weight of the expansion / contraction excavation tool 1 operated by the air hammer E increases rapidly. (Particularly, the lower neck portion N of the expansion / contraction excavation tool 1 shown in FIG. 4), the strength (rigidity) of the shank root portion S where stress concentrates is relatively insufficient, and an accident that breaks from this portion may occur. It was. Furthermore, in the expansion / contraction type excavation tool 1, since excavation is performed by expanding the diameter, excavation resistance is inevitably higher than that of a normal fixed excavation tool. Since this tendency becomes more conspicuous in large-diameter excavation, the root portion S of the shank where stress is concentrated most often breaks, and there is a problem that stable excavation may not be possible.

  Such a situation becomes particularly prominent when the diameter of the excavation hole exceeds 800 mm, and it is necessary to excessively reduce the excavation speed in order to suppress excavation resistance, and the time and labor required for excavation are excessive. There was a problem of becoming. In addition, even if the excavation speed is lowered to reduce the excavation resistance, the excavation tool 1 may break, and there is a problem that stable excavation work and casing pipe embedding work cannot be performed.

Further, since the expansion / contraction type excavation tool 1 is heavy, there is a problem that a lot of time and labor are required for handling the excavation tool 1 such as transportation, replacement, and setting.
Further, when manufacturing a large-diameter expansion / contraction excavation tool 1, large device materials are required, and handling when attaching these large materials to a machine tool becomes difficult. There has been a problem that the manufacturing cost of the product greatly increases.

  Further, in the expansion / contraction excavation tool 1, a plurality of bit heads 6 are attached to one device portion 2, but there is only one air hammer E that strikes the expansion / contraction excavation tool 1. The bit head 6 is hit at once. When excavating the ground, various geological formations will be excavated, and it is necessary to hit all the bit heads 6 even when the strata that require a lot of striking and the strata that can be excavated with a few striking are mixed. There was a problem that the efficiency of excavation work deteriorated.

  The present invention has been made in view of the above-described circumstances, and is capable of stably and efficiently forming a large-diameter excavation hole and is easy to handle and inexpensive to manufacture. An object of the present invention is to provide a drilling method capable of forming a tool and a large-diameter excavation hole and embedding a large-diameter casing pipe.

  In order to achieve the above object, the present invention provides a drilling tool disposed at the tip of a rotatable drill rod, wherein a plurality of bit units are centered on the axis of rotation of the drill rod at the tip of the drilling tool. The bit unit includes a bit head having a tip fixing portion in which a tip made of a hard material is arranged on the tip side, and the bit head is eccentric from the rotation shaft of the drill rod. And a device having a support portion rotatably supported around an axis extending in parallel with the rotation axis, and a device provided with a mounting portion to an air hammer on the rear end side, the device being a predetermined tool of the excavation tool A fixing means that is fixed in position and prevents rotation of the device itself is provided, and the bit heads of the plurality of bit units are arranged on the tip side of the excavation tool. Tsu isolation portion is formed by each of the bit head rotates about said axis, an outer diameter of the bit portion is characterized in that it is possible scaling.

  In the excavation tool having the above-described configuration, a bit portion is formed on the distal end surface of the excavation tool by the respective bit heads provided in the plurality of bit units, and each bit unit is provided with a mounting portion that connects to the air hammer. , One air hammer can be connected to each bit unit, and by using multiple small diameter air hammers, the weight of the lower neck part of one unit bit can be greatly reduced, and the strength of the shank root part is relatively improved In addition, a relatively small-diameter air hammer having sufficient absolute strength can be selected, and a drilling tool capable of stably forming a large-diameter drilling hole can be configured.

  Therefore, it is not necessary to use a large-diameter air hammer, and the device mounted on the air hammer can be made small, so that the manufacturing cost of the drilling tool can be greatly reduced and the drilling tool can be easily handled and excavated. Can save labor and time. In addition, there is no risk that the bit head or device will break due to excavation resistance, and it is possible to stably form a large-diameter excavation hole and reduce the time and labor required for excavation work without the need to excessively reduce the excavation speed. it can. Furthermore, since each bit unit can be hit independently, only the bit unit in the hard part of the formation can be hit, and excavation can be performed efficiently.

  In addition, since the bit head of each bit unit is fixed to the support portion of the device fixed so as not to rotate at a predetermined position of the excavating tool so as to be rotatable about the axis of the bit head, the excavating tool is attached to the tool. When rotating in the rotation direction, the bit portion is expanded in diameter by excavation resistance received from the material to be excavated. Further, by rotating the excavation tool in the direction opposite to the tool rotation direction, the diameter of the bit portion is reduced by the frictional resistance with the excavation hole. Therefore, the excavation hole can be formed with the diameter of the bit portion enlarged, and the excavation tool can be taken out from the excavation hole with the diameter of the bit portion reduced.

  Also, a ring-shaped casing top is arranged on the outer peripheral side of the plurality of devices arranged, a casing pipe is attached to the casing top, and the device and the axial tip are arranged on the rear end side of the casing top. By providing a striking transmission unit that collides with the air hammer and transmits the blow of the air hammer to the casing pipe, the blow from the air hammer applied to the device can be transmitted to the casing pipe, and the work of embedding the casing pipe simultaneously with the excavation work It can be done efficiently. In addition, since the bit portion formed by the bit heads provided in the plurality of bit units can be expanded / contracted, the bit portion is reduced in diameter and passed through the inside of the casing top and the casing pipe to be opposite to the drilling direction. The excavation tool can be taken out while the casing pipe is embedded.

  Further, in the excavation method characterized in that excavation is performed using the excavation tool having the above-described configuration and excavation in the excavation direction and the casing pipe is embedded in the ground, the casing pipe is embedded in a predetermined position simultaneously with excavation. Therefore, the large-diameter excavation work and the large-diameter casing pipe burying work can be stably and efficiently performed, and the cost required for the large-diameter casing pipe burying work can be reduced. it can.

  In addition, excavation is performed using the excavation tool having the above-described configuration, excavation is performed in the drilling direction, the casing pipe is buried in the ground, the casing pipe is moved to a predetermined position, and then the casing pipe is submerged. In the excavation method, in which the excavation tool is collected in the opposite direction with respect to the drilling direction, the casing pipe can be embedded accurately and reliably.

  Therefore, according to the present invention, for example, a large-diameter excavation hole having a excavation diameter exceeding 800 mm can be stably and efficiently performed, and the expansion and contraction excavation is easy to handle and inexpensive to manufacture. An object of the present invention is to provide a drilling method capable of forming a tool and a large-diameter excavation hole and embedding a large-diameter casing pipe.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 3 show an excavation tool 21 according to an embodiment of the present invention. Here, FIG. 1 is a cross-sectional explanatory view of the excavating tool 21, and on the left side of the rotation axis O of FIG. One bit unit 22 in a state where the diameter of the bit portion 23 is reduced is shown on the right side.

As shown in FIGS. 2 and 3, the excavation tool 21 has three bit units 22, and these bit units 22 are arranged at equal intervals on the circumference around the rotation axis O. . And the bit part 23 is formed in the front end surface of the excavation tool 21 by the bit head 51 with which each bit unit 22 was equipped.
The bit unit 22 includes a bit head 51 having a fan-shaped flat plate on the tip side (lower side in FIG. 1), and a device 31 that rotatably supports the bit head 51 and has a mounting portion 32 for an air hammer. ing. Further, a housing portion 24 having a shape complementary to the outer shape of the device 31 is formed as a fixing means for receiving and fixing the device 31 on the distal end side of the excavation tool 21, and the device portion 31 is formed by the housing portion 24. It is fixed so that it does not rotate.

The device 31 includes a cylindrical mounting portion 32 having a small diameter, and a columnar device body 33 whose section perpendicular to the axis L of the column formed by the mounting portion 32 is generally fan-shaped. The mounting portion 32 is an air hammer. Each of the devices 31 is connected to one air hammer, and the air hammer is connected to one device 31. That is, three air hammers are connected to the excavation tool 21.
The angle formed by the two fan-shaped straight portions formed by the cross section of the device body 33 is 120 °, and the three devices 31 are arranged so as to roughly constitute one cylinder. On the side surface 33A formed by the fan-shaped arc-shaped portion, a concave groove 34 is formed for taking out excavation debris of the work material.

  A concave portion 35 having a circular cross section extending perpendicularly to the fan-shaped distal end surface is formed in the distal end surface of the device main body 33, and a circular center formed by the concave portion 35 and a cylindrical axis L formed by the mounting portion 32. Are arranged to match. The concave portion 35 is a support portion that supports the bit head 51. A cylindrical retaining pin 36 is inserted so as to penetrate the outer peripheral portion of the recess 35 from the arc-shaped side surface 33A of the device body 33 and perpendicularly intersect the direction in which the recess 35 extends. Further, the device 31 is formed with a through-hole 37 having a circular cross-section that is opened at the rear end surface of the mounting portion 32 and opened at the bottom surface of the recess 35 along the axis of the cylinder formed by the mounting portion 32.

On the rear end side of each device main body 33, a protruding portion 38 protruding toward the arc-shaped side surface 33A is formed. The protruding portions 38 of the three devices 31 have a ring shape except for the concave groove 34 portion. A stepped portion 39 is formed.
A substantially ring-shaped casing top 41 is mounted on the outer peripheral portion of the column formed by the three devices 31, and the rear end surface of the casing top 41 is disposed so as to contact the stepped portion 39. The casing top 41 has a thick portion 41A on the front end side (lower side in FIG. 1) and a thin portion 41B on the rear end side (upper side in FIG. 1), and is formed between the thick portion 41A and the thin portion 41B. A tapered surface portion 41C is formed therebetween. The tip end portion of the casing pipe 42 is welded to the tapered surface portion 41C. Further, the thin portion 41 </ b> B in contact with the stepped portion 39 serves as an impact transmitting portion that receives the impact of the air hammer through the device 31 and transmits it to the casing pipe 42.

  In the bit head 51, a tip fixing portion 52 having a substantially fan-shaped flat plate shape is formed on the tip end side, and the tip end surface of the tip fixing portion 52 has a button shape made of a hard material such as cemented carbide. A plurality of chips 53 are fixed. The bit head 51 has a pair of straight side surfaces 51A and 51B and an arc-shaped side surface 51C when viewed from the tip side of the excavating tool 21, and the length of one side surface 51A is the casing. The outer radius of the pipe 42 is longer, and the length of the other side surface 51 </ b> B is shorter than the outer radius of the casing pipe 42. The angle formed by the pair of linear side surfaces 51 </ b> A and 51 </ b> B is 120 °, and the bit portion 23 is formed by the three bit heads 51.

An attachment shaft portion 54 that is formed in a cylindrical shape and extends perpendicularly to the rear end surface of the chip fixing portion 52 is provided at the center of the rear end surface of the chip fixing portion 52. A ring-shaped groove 55 having a hemispherical bottom surface is formed on the outer peripheral surface of the mounting shaft portion 54.
Further, an exhaust hole 56 having a circular cross section extending from the front end surface of the bit head 51 along the axis of the mounting shaft portion 54 is provided.

The mounting shaft portion 54 of the bit head 51 is fitted into the concave portion 35 of the device 31, and the columnar retaining pin 36 is inserted so as to be slidable with a part of the bottom surface of the ring-shaped groove 55. The bit head 51 is supported so as to be rotatable about the axis of the mounting shaft portion 54 while being fixed so as not to come off the device 31. Here, the opening portion of the rear end surface of the mounting shaft portion 54 of the exhaust hole 56 of the bit head 51 is arranged so as to be continuous with the opening portion of the bottom portion of the concave portion 35 of the through hole 37 formed in the device 31.
As shown in FIGS. 2 and 3, one side surface 51 </ b> A of each bit head 51 is disposed so as to contact the other side surface 51 </ b> B of the adjacent bit head 51.

The excavation tool 21 having the above-described configuration is attached to the tip end side of the drill rod, rotated in the tool rotation direction X, and sent to the excavation material such as the ground while being hit by an air hammer, and the excavation material A drilling hole is formed on the surface.
When the air hammer is struck, the compressed air is discharged toward the tip surface of the bit head 51 through the through hole 37 and the exhaust hole 56. With this compressed air, excavation debris and the like on the front side of the bit head 51 are expelled toward the concave groove 34, and the discharge of the excavation debris is promoted so that excavation is performed smoothly.

  When the excavation tool 21 is rotated in the tool rotation direction X, each bit head 51 is rotated about the axis of the cylinder formed by the attachment shaft portion 54 due to excavation resistance from the material to be excavated, and the other side surface 51B is Of the one side surface 51A of the adjacent bit head 51, it is brought into contact with a portion opposite to the arc-shaped side surface 51C, and as shown in FIG. 2, a pair of linear side surfaces 51A, 51B of each bit head 51 One side surface 51A, which is arranged so that the intersecting portion coincides with the rotation axis O of the excavating tool 21 and is longer than the outer radius of the casing pipe 42, protrudes outward from the outer diameter of the casing pipe 42, and has three bits. The diameter of the bit part 23 formed by the head 51 is increased. By excavating in this state, an excavation hole having a diameter larger than that of the casing top 41 and the casing pipe 42 is formed, and the casing pipe 42 is embedded by the striking force applied to the casing top 41 from the stepped portion 39. .

On the other hand, when the excavation tool 21 is rotated in the direction opposite to the tool rotation direction X (rotation direction Y in FIG. 3) after the excavation is completed, each bit head 51 is a cylinder formed by the mounting shaft portion 54 due to frictional resistance with the excavation hole. The other side surface 51B is in contact with the arc-shaped side surface 51C side portion of one side surface 51A of the adjacent bit head 51, and as shown in FIG. The bit portion 23 formed by 51 is reduced in diameter to be smaller than the inner diameter of the casing top 41.
Therefore, since the excavation tool 21 can be taken out through the casing top 41 and the casing pipe 42 with the bit portion 23 having a reduced diameter, only the casing pipe 42 can be reliably embedded in a predetermined position of the excavation hole. .

In the excavation tool 21 having the above-described configuration, air hammers are formed on the three bit heads 51, respectively. By using three air hammers having a small diameter, for example, an excavation diameter of about 300 mm, a large diameter, for example, an excavation diameter is obtained. A drilling hole of about 800 mm can be stably excavated. Therefore, there is no need to attach the large-diameter bit head 51 or the device 31 to the small-diameter air hammer, and there is no possibility that the attachment shaft portion 54 of the bit head 51 or the root portion of the mounting portion 32 of the device 31 is broken due to excavation resistance. Further, since the bit head 51 and the device 31 to be mounted on the air hammer are small and light in weight, the excavation tool 21 can be easily handled, transported, exchanged, set, and manufactured. Cost can be greatly reduced.
Further, the three bit heads 51 can be hit independently, and the bit head 51 can be hit according to the formation to be excavated, so that excavation work can be performed efficiently.

In addition, a casing top 41 for connecting the casing pipe 42 is disposed on the outer periphery of the device 31, and an impact transmission unit is provided on the casing top 41, so that the hammer hammer is transmitted to the casing pipe 42 through the device 31, The casing pipe 42 can be buried smoothly.
Further, since the casing pipe 42 is embedded while excavating in the state where the bit portion 23 is expanded, the excavation tool 21 can be taken out through the casing top 41 and the casing pipe 42 while the bit portion 23 is reduced in diameter. The large-diameter casing pipe 42 can be embedded at a predetermined position.

In the present embodiment, the combination of three sets of bit units 22 has been described. However, the present invention is not limited to this. For example, the bit units 22 include two sets of semicircular bid heads 51, Four or more sets of bit units 22 may be combined.
In addition, the bit head 51 has a fan-shaped configuration, and each bit head 51 has a structure in which the side surfaces of the adjacent bit heads 51 are in contact with each other. However, the present invention is not limited to this. Are provided with a plurality of notches that are open toward the front side in the tool rotation direction X and the outside in the tool radial direction, and a plurality of triangular bit heads 51 that are accommodated in these notches are arranged. The bit head 51 may be supported on the wall surface on the rear side in the direction X, and the bit head 51 may be supported on the inner wall surface in the tool radial direction when the diameter is reduced.
Further, although the excavating tool 21 is provided with the housing portion 24 as a fixing means for fixing the device 31, the present invention is not limited to this, and the device 31 is placed at a predetermined position of the excavating tool 21 and the device 31. What is necessary is just a structure of fixing so that itself may not rotate.

It is a section explanatory view of an excavation tool which is an embodiment of the present invention. It is a front view in the state where the excavation tool of FIG. 1 expanded the diameter. It is a front view in the state where the excavation tool of FIG. It is sectional explanatory drawing of the conventional excavation tool. It is a front view in the state where the excavation tool of FIG. 4 expanded the diameter. FIG. 5 is a front view of the excavation tool of FIG. 4 with a reduced diameter.

Explanation of symbols

21 Excavation tool 22 Bit unit 23 Bit part 24 Housing part (fixing means)
31 Device 32 Mounting part 35 Recessed part (supporting part)
41 Casing top 42 Casing pipe 51 Bit head 53 Tip 54 Mounting shaft D Drill rod

Claims (4)

A drilling tool arranged at the tip of a rotatable drill rod,
A plurality of bit units are provided circumferentially around the rotation axis of the drill rod on the tip side of the excavation tool, and the bit unit is fixed to a tip in which a tip made of a hard material is arranged on the tip side. A bit head having a portion, and a support portion that supports the bit head eccentrically from the rotation shaft of the drill rod so as to be rotatable about an axis extending in parallel with the rotation shaft, and to the air hammer on the rear end side. It consists of a device with a mounting part,
The device is fixed at a predetermined position of the excavation tool, and provided with a fixing means for preventing rotation of the device itself,
A plurality of bit heads of the plurality of bit units form a bit portion on the tip side of the excavation tool, and the outer diameter of the bit portion can be expanded and contracted by rotating each bit head about the axis. An excavation tool characterized by   A ring-shaped casing top is arranged on the outer peripheral side of the plurality of devices arranged, a casing pipe is attached to the casing top, and the device and the axial direction are arranged on the rear end side of the casing top. The excavation tool according to claim 1, further comprising an impact transmission unit that collides with a distal end side and transmits impact of the air hammer to the casing pipe.   An excavation method characterized in that excavation is performed using the excavation tool according to claim 2 to excavate in the drilling direction and the casing pipe is buried in the ground.   4. The excavation method according to claim 3, wherein after the casing pipe is buried to a predetermined position, the excavation tool is recovered on the side opposite to the drilling direction while leaving the casing pipe in the ground.

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