JP2000282773A - Enlarged head for drilling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of pulling up an enlarged head for an inside digging method having an enlarged wing for forming a rooted bulb in a hollow pile by reverse rotation. SOLUTION: A projecting piece 20 for preventing an enlarged bit from contacting an inner wall of a hollow pile is provided on an enlarged wing, and a stabilizer 40 (40a, 40b) for restricting a deviation between a rotation center of the enlarged head and a center of the hollow pile. , 40c, 40d).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an enlarged head for a middle digging method.

[0002]

2. Description of the Related Art Inserting an auger screw into a hollow pile,
There is a so-called digging method in which a digging tool is attached to the tip of the pit to excavate the ground and excavate the soil while laying the pile in the ground. In this construction method, there is also a method of using a magnifying head having a magnifying wing to reach a supporting ground and then forming a root consolidation bulb below the pile using the magnifying wing. The mechanism for expanding the diameter of the enlarged wing by the middle excavation method includes a technique of performing the excavation by the forward rotation and a technique of expanding the diameter by the reverse rotation. Here, the forward rotation is a rotation direction in which earth can be discharged by rotation of the auger screw.

[0003] To expand the diameter by forward rotation, a mechanical expanding device, a hydraulic device, or the like is used. However, the mechanism and structure become complicated, and it is necessary to maintain the reduced diameter while the pile is laid down. Requires a diameter reduction mechanism. The technique of expanding the diameter by reverse rotation is relatively simple in structure because the diameter is expanded by using the force of the tip that the expansion bit bites into the ground, and the diameter is easily reduced by forward rotation.

[0004] In the case of normal drilling of a pile, when the auger is lifted after excavation, the auger is rotated in a reverse direction to drop the earth and sand attached to the auger screw, to reduce the weight of the auger itself, to facilitate the auger pulling operation, and to discharge to the ground. It is done to reduce sedimentation. In the case of an expanding head of a type in which the diameter is increased by reverse rotation, when the head is reversed in the pile, the tip of the bit of the expanding wing contacts the inner wall of the pile, and the diameter is expanded inside the pile. As a result, reverse rotation becomes impossible due to the contact resistance of the expanding wing, and the auger must be pulled up in a state of normal rotation or no rotation. Further, when the screw auger is pulled out by a crane or the like, the screw auger naturally rotates reversely due to the resistance between the screw and the soil inside the pile. Also in this case, the diameter of the expanding wing is increased in the pipe, so that contact resistance is generated, and it becomes difficult to pull out.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a technique capable of pulling up an inside head of a hollow pile by a reverse rotation of such an enlarged head for a middle digging method in which the diameter is increased by a reverse rotation. And

[0006]

SUMMARY OF THE INVENTION The present invention relates to an enlarged head for an inside digging method having an enlarged wing for forming a compacted bulb, and comprises a projecting piece for preventing an enlarged bit from contacting the inner wall of a hollow pile. And a stabilizer for restricting the deviation between the rotation center of the enlarged head and the center of the hollow pile is provided. Also,
It is preferable that the protruding piece be a resistance reducing mechanism such as a roller.

[0007]

FIG. 1 is a view of an enlarged head as viewed from above. Even if the expanding head is rotated in the reverse direction, the expanding wing 11
A protrusion 20 such as a roller for reducing the contact resistance of the enlarged wing 11 so that the tip of the bit does not contact the inner wall of the pile.
And a stabilizer 40 (40a, 40b, 40c, 40) for suppressing the displacement of the auger shaft.
d) is provided to enable the auger to be pulled out in the reverse rotation.

FIG. 8 is a side view of the enlarged head 10 at the lower end of the auger shaft. Expanding head 1 below screw shaft 100
0 is attached. The expansion head 10 includes an expansion wing 11 that expands and contracts. At the lower end of the enlarged head 10 there is a single-sword drilling blade 12 and a blade 14 with a drilling bit 13. Above it, an enlarged wing 11 is provided. FIG. 9 is a plan view showing a state where the diameter of the enlarged wing 11 is reduced (11a) and a state where the diameter is enlarged (11b). The enlarged wing 11 is a pin 15
, For example, with a nominal diameter of 8
For a steel pipe pile having a thickness of 00 mm and a thickness of 10 mm, the circle 51 drawn by the tip of the tip bit when the diameter of the enlarged wing is reduced is 680 mm.
φ, circle 52 drawn by the tip of the tip bit when the diameter is expanded
Is 1000 mmφ. FIG. 1 shows an enlarged wing 10 with a steel pipe pile 1
It is a top view when it is stored in 10. Magnifying wings 10
A projection 20 is provided on the surface opposite to the bit 16. The projection 20 is in contact with the inner wall of the steel pipe pile 110. FIG.
Is a roller. In FIG. 1, the axis of the enlarged head 10 coincides with the axis of the steel pipe pile 110. When this is greatly deviated, the tip of the tip bit 16 of the enlarged wing contacts the pile inner wall 111 regardless of the presence of the projection 20. Then, since the auger is rotating in the reverse direction, the expanding wing 11 receives a force in the radially expanding direction, and the bit 16 bites into the inner wall of the pile. In order to prevent such a fear, a stabilizer 40 (40a, 40b, 40c, 40d) for keeping the axis of the enlarged head 10 and the axis of the steel pipe pile 110 at substantially the same position is provided. In FIG. 1, the stabilizers are the stabilizers 40 a and 40 b protruding in the direction (AA direction) connecting the center of the pin of the enlarged wing 11, and the direction perpendicular to the directions (BB direction).
Of stabilizers 40c and 40d protruding in the radial direction
A book-shaped stabilizer is attached to the enlarged head 10.

In FIG. 2, the center of the enlarged head is the enlarged wing 11.
In the direction connecting the pin shafts (A-A direction), when the eccentricity is maximized to the left as viewed in the figure, the stabilizer is set so that the tip of the bit 16a on the upper side of the figure keeps the minimum dimension so as not to contact the inner wall 111 of the pile. Is shown. Similarly, FIG. 3 shows the case where the eccentricity is maximum in the BB direction at the top of the figure, and FIG. 4 shows the case where the eccentricity is maximum in the oblique upper left direction at 45 ° to the AA direction and the BB direction. The state is shown. The projection 20 and the stabilizer 40 (40a, 40b, 40c,
The relationship with 40d) is a preferable relationship in which the tip of the bit of the enlarged wing 11 does not contact the inner wall surface of the pile even when the enlarged head 10 is in any deviation state. These relationships can be determined geometrically by the position of the mounting pin 15 of the enlarged wing 11, the shape and size of the enlarged wing 11, the inner wall size of the pile 110, the attached position of the projection 20, the shape and number of the stabilizer, and the attached position. Can be.

FIG. 5 shows the protrusion 20 shown in FIG. The projection 20 includes a bracket 21 attached to the enlarged wing 11 and a roller 22 supported by the bracket 21 with a pin 23. The outer periphery of the roller 22 abuts on the inner wall of the pile. FIG. 6 shows another example of the projection 20.
Is attached to the enlarged wing 11 and has a half-moon shaped contact piece 25.
The outer periphery of abuts against the inner wall of the pile. FIG. 7 shows a configuration in which a bracket 31 in which a sphere 30 such as a bearing steel ball is rollably embedded is attached to the enlarged wing 11 so that the outer peripheral surface of the sphere 30 comes into contact with the inner wall surface 111 of the steel pipe pile 110. is there.

The stabilizer 40 is a plate-shaped stabilizer 40a, 40b, 40c, 40 as shown in FIG.
d may be attached to the enlarged head shaft near the enlarged wing 11, or may be another type. The point is to maintain the deviation between the axis of the enlarged head and the axis of the steel pipe pile within a desired range, as long as it does not cause breakage or deformation during excavation.
Further, the number of attachments is not limited. For example, a means for attaching a plurality of projecting pieces to the outer periphery of the blade of the spiral auger at a position close to the expanding wing, a ring-shaped member, or the like, or a combination of these as appropriate may be used.

[0012]

According to the present invention, when the auger reverses in the pile, the enlarged bit at the tip of the enlarged wing does not come into contact with the pile inner wall and the pile is expanded, so that it is possible to pull up in the reverse direction.

[0013] By enabling the auger to be pulled up in the reverse rotation, the auger can be pulled out while dropping the earth and sand attached to the auger into the pipe. Reduction of sediment has been achieved.

[Brief description of the drawings]

FIG. 1 is a plan view of a portion of an enlarged wing according to an embodiment.

FIG. 2 is an explanatory diagram of the deviation in FIG.

FIG. 3 is an explanatory diagram of the bias in FIG. 1;

FIG. 4 is an explanatory view of the bias in FIG. 1;

FIG. 5 is an explanatory view showing an example of a projection attached to an enlarged wing.

FIG. 6 is an explanatory view showing another example of a projection attached to an enlarged wing.

FIG. 7 is an explanatory view showing another example of a projection attached to the enlarged wing.

FIG. 8 is a side view of the enlarged head unit.

FIG. 9 is an explanatory diagram of expansion and contraction of an enlarged wing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Magnification head 11 Magnification wing 12 Drilling knife 13 Drilling bit 15 Pin 16, 16a Bit 20 Projection 21 Bracket 22 Roller 23 Pin 25 Half-moon shaped contact piece 26 Base pin 27 Fixture 28 Fixing bolt 40 (40a, 40b, 40c, 40d) ) Stabilizer 51 Circle drawn by enlarged wing tip when diameter is reduced 52 Circle drawn by enlarged wing tip when diameter is increased 100 Screw shaft 110 Steel pipe pile 111 Inner wall surface

Continuation of the front page (71) Applicant 592195126 Nozaki Construction Co., Ltd. 223-3 Shinko, Mihama-ku, Chiba-shi, Chiba (71) Applicant 591205536 Kawatetsu Techno Construction Co., Ltd. 2-17-4 Kuramae, Taito-ku, Tokyo (72) Inventor Yasushi Wakiya 2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Inside Kawasaki Steel Corporation (72) Inventor Takuya Motoki 2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Kawasaki Steel Corporation (72) Invention Ken Takeshi Oki 2-3-2 Uchisaiwai-cho, Chiyoda-ku, Tokyo Kawasaki Steel Corporation (72) Inventor Hachiro Inoue 4-12-9 Hokuei, Urayasu-shi, Chiba Tokyo Company, Ltd. (72) Inventor Sumi Kouji 2-10-10 Koraibashi, Chuo-ku, Osaka City, Osaka Prefecture Inside Geotop Co., Ltd. (72) Inventor Kazuo Fukuda 223 Shinko Minato, Mihama-ku, Chiba-shi, Chiba Nozaki Construction Works Co., Ltd. (72) Inventor Norihiro Morimoto 2-17 Shiohama, Ichikawa-shi Kawatetsu Techno Construction Co., Ltd. Company F term (reference) 2D029 EB04 2D041 AA03 BA12 CB06 2D050 AA02 BB04 CA02 CB03 CB09

Claims (1)

[Claims] 1. An enlarged head for an inside digging method having an enlarged wing for forming a root compaction bulb, wherein a projecting piece for preventing an enlarged bit at a tip end of the enlarged wing from contacting an inner wall of a hollow pile is provided on the enlarged wing. And a stabilizer for restricting the deviation between the center of rotation of the enlarged head and the center of the hollow pile.