JP2002348863A - Screwed pile and execution method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screwed pile and an execution method therefor, which are characterized as follows: (1) enlargement of a diameter of a pile end and mounting of a blade bring about great end bearing capacity in such a manner that a diameter of a pile body is made small; (2) length of an overhang of the blade from the pile body is made shorter to make an influence little exerted by bending, and the blade and the pile body are made smaller in board thickness; and (3) an auger can be easily recovered in a case of execution with concurrent use of the auger. SOLUTION: In the screwed pile whose pile body 3 fitted with the blade 6 is rotated to be made to penetrate into ground by action of the blade 6, an end of the pile body 3 is provided with an diameter-enlarged part 4 formed as a truncated cone-shaped or cylindrical body, and the blade 6 is provided at least at an end or in the vicinity of the diameter-enlarged part 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a threaded pile and a method for constructing a threaded pile, and more particularly, to a method of applying a rotating force to a pile having wings attached at least at or near the tip end thereof, so that the pile is underground. The present invention relates to a threaded pile and a method of constructing the threaded pile to be buried in the pile.

[0002]

2. Description of the Related Art A wing plate is attached to the tip or side of a pile,
Various types of screw-in piles buried in the ground by wood screw action of wing plates by applying rotational force using construction machines installed on the ground have been proposed in the past with low vibration, low noise, and no soil removal. As well as being able to use the area of the wing-shaped plate after embedding, it can be used in the fields of civil engineering and construction because a large tip supporting force can be obtained. Hereinafter, the related art considered to be related to the present invention will be described.

[0003] In the method of burying steel pipe piles described in Japanese Patent Publication No. 2-62848, a bottom plate is fixed to the lower end of a steel pipe pile body, a digging blade is provided on the bottom plate, and an outer periphery of the lower end of the pile body is provided. A spiral wing for screwing a pile with a large wing width, which has an outer diameter almost twice as large as the outer diameter of the pile body on the surface, is rotated so that a steel pipe pile projecting over almost one turn is screwed into soft ground. While pushing it into the ground, excavating and softening the soil at the tip of the pile body with the drilling blade at the lower end, causing the spiral wings to bite into the undigged earth and sand on the side of the pile, and rotating the pile body as a reaction force with the strength of the soil as a reaction force While extruding and softening the excavated softened soil to the side of the pile,
The pile body is screwed into the ground without earth removal (prior art 1).

[0004] Further, in the steel pipe pile described in Japanese Patent Application Laid-Open No. 2000-110162, a tapered steel pipe having a large diameter below the steel pipe pile is used to increase the allowable penetration depth based on the maximum diameter of the pile. By this, while lowering the embedding cost including the material cost of the pile, the cone is fixed to the lower end of the tapered steel pipe, and the spiral wing is attached to the side of the steel pipe above it,
The spiral blade converts the rotational force into a thrust and increases the supporting force (prior art 2).

Further, the expanded steel pipe pile described in Japanese Patent Application Laid-Open No. 2000-110160 is constructed such that the ground is excavated and the expanded steel pipe pile is laid down by the middle digging method, and the expanded bottom part is fixed to the root consolidation part. Adhesion-preventing wings that can expand to a diameter approximately equal to the inside diameter of the connecting part prevent the adhesion of viscous soil and slime that enter the inside of the corner between the connecting part and the expanding part, ensuring high tip support force (Prior Art 3).

[0006]

The steel pipe piles according to the prior arts 1 and 2 are screwed into the ground by applying a torque to the pile head with a construction machine and buried. In a steel pipe pile having such spiral blades, when the pile body or the spiral blades overhang becomes large, a large resistance acts during construction and a large torque is required. In operation, a large bending moment acts on the pile due to the ground reaction force acting on the spiral blade. For this reason, the pile must have a thickness or strength large enough to withstand a large torque during construction, and the thickness or strength of the pile should be increased during operation, or the plate thickness of the spiral blade should be equivalent. It needs to be thick, which is uneconomical.

[0007] The steel pipe pile of the prior art 3 can secure a large tip supporting force by enlarging the tip. However, since the pile body is not provided with wings, the inside digging method must be adopted for construction, which is not only troublesome in construction, but also must be treated to discharge excavated soil to the ground. No. In addition, it is possible to secure only the supporting force for the diameter of the expanded steel pipe.

The present invention has been made in view of the above problems, and has as its object to provide a screwed pile and a method of constructing the screwed pile which solve the following problems. (1) To obtain a large tip supporting force with a small pile body diameter by expanding the tip of the pile and providing wings. (2) To reduce the influence of bending by shortening the wing length of the wing from the pile body, and to enable economical design by reducing the thickness of the wing and the pile body. (3) When the auger is used in combination, the insertion and collection of the auger should be easy.

[0009]

(1) The present invention relates to a screw-in pile which rotates a pile provided with wings and penetrates the pile into the ground by the action of the wings. And a wing is provided at least at the tip of the enlarged diameter portion or in the vicinity thereof.

(2) In the screw pile according to (1),
The enlarged diameter portion is formed in a truncated conical shape in which the outer diameter of the upper end is substantially equal to the outer diameter of the pile, and the outer diameter of the lower end is larger than the outer diameter of the pile. The portion was joined to the tip of the pile body.

(3) In the screw pile according to the above (1),
The enlarged diameter portion is formed of a cylindrical body having a diameter larger than the outer diameter of the pile body, and the enlarged diameter portion is joined to the tip end of the pile body via a donut-shaped, disk-shaped or elliptical joint member. Was configured.

(4) In the screwed pile according to the above (3),
Instead of a donut-shaped, disk-shaped or elliptical joint member, the joint member was formed in a wing shape having a diameter larger than that of the pile body. (5) In the screw pile according to any one of (1) to (4), the wing was joined to the inner wall of the enlarged diameter portion.

(6) The method for constructing a screw-in pile according to the present invention is characterized in that the wing and the joint member have a central opening in the above (1) to (1).
The auger head is protruded from the tip of the pile by inserting an auger into any of the threaded piles of (5), and the threaded pile is penetrated into the ground by the action of the auger and the wing.

(7) In the method for constructing a threaded pile according to the above (6), a through hole is provided in an auger direction of the auger and a spout is provided in the auger head. It was made to squirt from the exit.

[0015]

[First Embodiment] FIG. 1 is a perspective view of a screw pile according to a first embodiment of the present invention, and FIG. 2 is a schematic longitudinal sectional view of FIG. In both figures, 1 is a threaded pile, 3 is a pile made of a steel pipe, 4 is a tapered enlarged portion which is formed by bending a steel plate and is welded to the tip of the pile 3 by welding. The pile body 2 is constituted by 3 and the enlarged diameter portion 4. Reference numeral 6 denotes a blade joined to the tip of the enlarged diameter portion 4 by welding.

The enlarged diameter portion 4 has an outer diameter at an upper end portion substantially equal to an outer diameter of the pile body 3 and is formed in a truncated conical shape with an enlarged diameter toward a lower portion. A mounting portion 5 cut in a shape is provided, and a spiral wing 6 formed by bending, for example, a donut-shaped steel plate is joined to the mounting portion 5 by welding.

According to the experimental results of the inventors, the diameter of the enlarged diameter portion 4 is desirably about 5 ° to 20 °. The thickness may be approximately equal to or slightly larger than the thickness of the steel pipe constituting the pile 3. In the case where the diameter expansion angle θ is large, the problem of load transmission can be dealt with by increasing the thickness of the diameter expansion portion 4. The length of the enlarged diameter portion 4 varies depending on the outer diameter of the pile 3 and the state of the ground, but according to the results of experiments by the inventors, it is 0.5 to 5 times the outer diameter of the pile 3. A degree is desirable.

The outer diameter of the wing 6 varies depending on the outer diameter of the lower end portion of the pile 3 or the enlarged diameter portion 4 or the state of the ground, but is generally 1.5 to 3.5 times the outer diameter of the pile 3. Degree is desirable,
In addition, it is desirable that the outwardly protruding length (width) and the inwardly protruding length (width) in a state where the enlarged diameter portion 4 is joined to the mounting portion 5 are substantially equal. Thereby, the ground reaction force acting on the wing 6 can be balanced when the pile is used as a foundation pile, and the bending moment acting on the enlarged diameter portion 4 can be reduced. If the length of the wing 6 protruding from the enlarged diameter portion 4 is about 20% of the outer diameter of the pile 3, the wing 6
, The pile 3 can be penetrated into the ground.

In the screwed pile 1 according to the present embodiment constructed as described above, the pile head or the upper body of the pile main body 2 is mounted on a motor provided on a construction machine, and the screwed pile is rotated by the motor. By doing so, the blade 6 penetrates into the ground with no earth removal, low vibration, and low noise by the wood screw action. At this time, the earth and sand under the wing 6 is excavated and softened by the wing,
After passing through the gap 8 of the wing 6, it moves to the outer periphery of the pile main body 2 and is compressed, and is also taken into the pile main body 2 from the central opening 7 of the wing 6. The earth and sand moved to the outer periphery of the pile body 2 is softened by the wings 6 during construction, so that the frictional resistance is small, and the threaded pile 1 can penetrate smoothly. And
As the time elapses, the ground strength recovers, a large peripheral friction force is exhibited when the pile is used as a foundation pile, and a large supporting force can be obtained by the wing 6.

According to the present embodiment, even if the wing 6 having an outer diameter larger than the outer diameter of the pile body 2 is provided, the overhang length (width) from the outer periphery of the enlarged diameter portion 4 is short. The resistance of the ground is small, so that the screwed pile can penetrate the ground with a small torque. In addition, it is only necessary to make the plate thickness of the enlarged diameter portion 4 approximately equal to or slightly larger than the plate thickness of the pile body 2, and the plate thickness of the wings 6 can be reduced, so that cost can be reduced and economical. is there. Further, the enlarged diameter portion 4 of the wing 6
When the overhang lengths (widths) of the inside and outside are substantially equal, the bending moment acting on the enlarged diameter portion 4 can be reduced. Can be made thinner.

In the screwed pile according to the present embodiment, since the opening 7 is provided at the center of the wing 6, earth and sand enter the pile main body 2 during construction. When the wing 6 reaches the hard support layer during construction, the tip end is closed and penetrates, but the diameter of the pile 3 increases (therefore, the opening 7 of the wing 6 is large), In the case of soft ground, there is a possibility that the tip closing effect cannot be obtained. In such a case, a plate or a projection may be provided in the enlarged diameter portion 4 in order to promote the tip closing effect (the same applies to the following embodiments).

In the above description, a case is shown in which the mounting portion 5 is formed by cutting off the tip end of the enlarged diameter portion 4 in a spiral shape, and one spiral blade 6 is joined to the mounting portion by welding. However, the spiral blade 6 may be divided into a plurality of parts and joined to the mounting part 5.
Further, in place of the spiral blade 6, a circular steel plate, an elliptical steel plate,
A wing of any shape or structure may be used as long as it can provide propulsion into the ground, such as by joining flat wings obtained by dividing a square steel plate or a donut-shaped steel plate into a plurality of pieces (hereinafter, referred to as a wing). The same applies to the embodiment described above.)

Further, although the case where the open type wing 6 having the opening 7 at the center is used is shown, a closed type wing which closes the opening at the tip end of the enlarged diameter portion 4 may be used. The opening of the distal end may be closed by the member described above. Further, the tip opening of the enlarged diameter portion 4 is partially closed by wings or other members, and the pile 2
The intrusion of earth and sand into the inside may be adjusted. As described above, the size of the opening at the distal end of the enlarged diameter portion 4 can be appropriately set. Further, an auxiliary excavation blade for improving penetration may be provided on the wing. Also, the case where the wings are provided at the tip of the enlarged diameter portion 4 has been described. Body 3
The mounting position of the wing can be selected as appropriate, such as being provided on the outer periphery or any one of them (the same applies to the following embodiments).

[Embodiment 2] FIG. 3 is a schematic longitudinal sectional view of a screwed pile according to Embodiment 2 of the present invention. In addition,
The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, instead of the tapered enlarged portion 4 of the first embodiment, the enlarged diameter portion 4a is formed by a cylindrical tubular body made of a steel pipe or the like having a diameter larger than the outer diameter of the pile body 3. The pile body 3 is joined to the pile body 3 via the joint member 9.

The outer diameter of the enlarged diameter portion 4 a is equal to the outer diameter of the pile 3.
It is made of a steel pipe having a thickness of about 1 to 2.5 times and having a thickness almost equal to or slightly greater than the thickness of the pile body 3, and the length thereof is set according to the first embodiment. Then, the distal end portion of the enlarged diameter portion 4a is spirally cut off in the same manner as in the first embodiment, and the mounting portion 5
The mounting portion 5 has an outer diameter of 1.5 to 3.5
The double spiral wing 6 is joined by welding.

The joint member 9 is formed of a donut-shaped steel plate having an inner diameter substantially equal to the inner diameter of the pile body 3 and an outer diameter substantially equal to the outer diameter of the enlarged diameter portion 4a. The upper surface of the enlarged diameter portion 4a is joined to the lower surface by welding. Since the thickness of the joint member 9 varies depending on the outer diameter of the pile 3 and the vertical load acting thereon, the thickness is determined by numerical calculation. In the above description, the joint member 9 is made of a donut-shaped steel plate. However, the joint member 9 may be made of a disk-shaped steel plate having an outer diameter almost equal to that of the enlarged diameter portion 4a and having no opening at the center. Alternatively, the enlarged diameter portion 4a may be formed of a cylindrical body having an elliptical cross section, and may be joined to the pile 3 by a joint member made of an elliptical steel plate. The construction method and operational effects of the screwed pile according to the present embodiment are almost the same as those of the first embodiment.

[Embodiment 3] FIG. 4 is a schematic longitudinal sectional view of a screwed pile according to Embodiment 3 of the present invention. In addition,
The same parts as those in the second embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, a joint member 9a is formed by wings instead of the joint member 9 made of a donut-shaped, disk-shaped, or elliptical steel plate of the second embodiment.

That is, the tip of the pile 3 is spirally cut to form the mounting portion 3a, and the upper end of the enlarged diameter portion 4a is spirally cut to form the mounting portion 5a. Then, a spiral wing-shaped joint member 9a formed by spirally bending a donut-shaped steel plate having an inner diameter substantially equal to the inner diameter of the pile body 3 and an outer diameter larger than the outer diameter of the enlarged diameter portion 4a is attached to the pile body 3. The attachment portion 3a is joined by welding, and the attachment portion 5a of the enlarged diameter portion 4 is joined to the lower surface by welding. The joint member 9a may be larger or smaller than the outer diameter of the wing 6, and if it is large, it mainly contributes to supporting force, and if it is small, it mainly contributes to propulsion. Further, the wing-shaped joint member 9a
Is not limited to a spiral blade, and a blade having an appropriate shape or structure can be used as in the case of the blade 6 described above.

The construction method, operation, and effects of this embodiment are almost the same as those of the second embodiment. However, since the joint member 9a is formed in a wing shape, the driving force of the screwed pile at the time of construction, It can contribute to the supporting force at the time.

[Embodiment 4] FIG. 5 is a schematic longitudinal sectional view of a screwed pile according to Embodiment 4 of the present invention. In the present embodiment, the spiral cutout portion 5 and the blade 6 provided at the tip of the tapered enlarged portion 4 in the first embodiment are omitted, and for example, a spiral blade is provided on the inner wall of the enlarged diameter portion 4. 6a joined by welding.

The construction method and operation and effect in this embodiment are almost the same as those in the first embodiment, and the wing 6a contributes as a driving force of the screwed pile during construction and as a support during operation. Also in the present embodiment, the enlarged diameter portion 4
A wing may be provided at the tip end or the outer periphery of the enlarged diameter portion 4 or the pile body 3, whereby the propulsion force and the support force into the ground can be further improved. In this case, if the wing 6a provided on the inner wall of the enlarged diameter portion 4 is mounted in the direction opposite to the rotation direction of penetration of the screwed pile 1, intrusion of earth and sand into the pile main body 2 is suppressed, and the tip opening is closed. The effect can be obtained. This embodiment can be implemented in the second and third embodiments.

[0032]

EXAMPLE The screw pile according to the first embodiment has an outer diameter of 50 mm.
0 mm, plate thickness 12 mm, length 20 m, at the tip of pile 3, outer diameter 500 mm at upper end, outer diameter 800 mm at lower end
(Expansion angle θ: 10 °), plate thickness 12 mm, length 1 m,
The upper end of the enlarged diameter portion 4 having the mounting portion 5 spirally cut at an angle of 15 ° at the tip was joined by welding. Then, a wing 6 formed in a spiral shape by cutting one place of a donut-shaped steel plate having an outer diameter of 1000 mm, an inner diameter of 500 mm, and a thickness of 30 mm in the radial direction and spirally bending the same is welded to the mounting portion 5. It was manufactured by bonding.

The ground to be constructed was a relatively soft sand layer up to 20 m, and a gravel layer having an N value of 50 or more at a depth below that.
When such a ground is penetrated by applying a rotational force to the above-mentioned screwed pile by a construction machine, it can be constructed with the same efficiency as a normal screwed pile, pulled out and inspected after penetration, deformation of the wing and other No abnormalities were seen.

[Embodiment 5] FIG. 6 is an explanatory view of a method for constructing a threaded pile according to Embodiment 5 of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 1 denotes a screw-in pile provided with an open wing 6 in the enlarged diameter portion 4, reference numeral 10 denotes an auger inserted into the screw-in pile 1, reference numeral 11 denotes an auger head, and reference numeral 12 denotes a spiral blade. Reference numeral 15 denotes a motor provided on a construction machine (not shown) installed on the ground, and includes two rotating shafts (an outer shaft 16 and an inner shaft 17) that rotate in opposite directions.

Next, the construction method of the present embodiment configured as described above will be described. First, an auger 10 slightly longer than the screwed pile 1 is inserted into the screwed pile 1,
The auger head 11 is protruded downward from the tip of the pile.
Then, the pile head of the screwed pile 1 is connected to the outer shaft 16 of the motor 15.
And the head of the auger 10 is connected to the inner shaft 17.
The auger head 11 used has an outer diameter that is slightly smaller than the inner diameter of the pile body 3, or a piece that protrudes downward from the central opening 7 of the wing 6 and then expands. Also in this case, it is desirable that the outer diameter of the auger head 11 be smaller than the outer diameter of the wing 6.

Next, for example, the screw 15 is rotated in the forward direction and the auger 10 is rotated in the reverse direction by the motor 15. As a result, the auger head 11 excavates and softens the ground near the tip portion prior to the screwed pile 1, and the screwed pile 1
Is penetrated into the ground by the wood screw action of the wing 6. At this time, the earth and sand near the tip of the screwed pile 1 moves to the upper periphery of the pile body 2 through the gap 8 of the wing 6, and a part of the earth and sand flows from the opening 7 of the wing 6 to the spiral blade of the auger 10. 1
By 2, it is taken into the pile body 2. When the tip of the pile reaches the support layer, the screwed pile 1 is removed from the motor 15, and the motor 15 is raised while rotating the auger 10 in the opposite direction with the screwed pile 1 remaining in the ground. , The auger 10 is pulled out from the screw-in pile 1, and the screw-in pile is buried in the ground to complete the construction.

The amount of earth and sand taken into the pile body 2 by the auger 10 varies depending on the size of the central opening 7 of the wing 6 and the size and shape of the auger head 11.
By adjusting these, earth and sand are prevented from overflowing from the pile main body 2. If the spiral blades 12 are attached at an inclination opposite to the rotation direction of the auger 10, it is possible to prevent earth and sand from entering the pile body 2. In this case, the torque decreases as the amount of sediment taken into the pile main body 2 increases. Further, as the amount of sediment taken into the pile main body 2 is smaller, the density around the pile main body 2 becomes higher, and a greater peripheral friction force is exerted.

According to the present embodiment, when the screwed pile 1 penetrates into the ground, the wing 6 is
In order to soften the ground before excavation, the torque required for rotating the screw-in pile 1 is greatly reduced as compared with the case where the auger 10 is not used. In addition, since the rotation directions of the screw-in pile 1 and the auger 10 are opposite, the reaction force from the motor 15 acting on the construction machine also becomes a reaction force due to a difference between the two torques, so that it is greatly reduced. Further, since the wing 6 is provided with an opening 7 having a diameter substantially equal to the inner diameter of the pile body 3,
The auger 10 can be easily inserted and collected. The auger 10 may be inserted into the screw-in pile 1 from the beginning, and may be inserted after the screw-in pile 1 has penetrated to some extent, for example, when it has reached the vicinity of the support layer.

[Embodiment 6] FIG. 7 is an explanatory view of a method for constructing a threaded pile according to Embodiment 6 of the present invention. The same parts as those in the fifth embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, in the axial direction of the central portion of the auger 10, a through-hole 13 for pressure-feeding a curable fluid such as cement milk or a liquid for solidifying the ground to the distal end portion is provided. The auger head 11 is provided with a spout 14 for spouting the curable fluid.

Reference numeral 18 is a construction machine installed on the ground, and 15 is the above-described motor provided on the construction machine. Numeral 20 denotes a plant for hardening fluid such as cement milk or soil hardening liquid (hereinafter referred to as hardening material plant). The auger 10 is rotatably connected to a through hole 13 provided in the auger 10 by a hose 21. I have.

In this embodiment, the threaded pile 1 penetrates into the ground in the same manner as in the fifth embodiment. When the threaded pile 1 has penetrated to an appropriate depth, the hardener plant 20 is driven and the auger 1 is
The hardening fluid is pressure-fed to the through hole 13 of 0, and is spouted from the spout 14 provided in the auger head 11, and is stirred and mixed with the excavated and softened earth and sand by the rotation of the auger head 11 and the blade 6. At this time, since the rotation directions of the screw pile 1 and the auger 10 are opposite, the hardening fluid and the earth and sand are well stirred to form a highly uniform mixture.

When the tip of the pile reaches the support layer, the support layer is sufficiently agitated by the wings 6 and the auger head 10 to mix the soil and hardening fluid well, and then the screw-in pile 1 and the rotation of the auger 10 are rotated. To stop. Then, the motor 15 is detached from the screw pile 1, and the motor 1 is rotated while the auger 10 is rotated in the opposite direction while the screw pile 1 is left in the ground.
When the auger 5 is raised, the auger 10 is pulled out from the screw-in pile 1, the screw-in pile is buried in the ground, and the construction is completed.

According to the present embodiment, the hardening fluid ejected from the tip of the auger 10 and the earth and sand are stirred and mixed, and the disturbed ground is solidified, so that a large tip supporting force can be exhibited. . The jetting section of the hardening fluid is determined in accordance with the peripheral friction of the screwed pile 1 necessary for design, and may be the entire section from the pile head to the pile tip or the pile tip. Only the vicinity may be used.

[0044]

(1) In the screw-in pile according to the present invention, the enlarged diameter portion is provided at the tip of the pile body, and the wing is provided at least at or near the tip of the enlarged diameter portion. Not only can it be constructed with low noise and low vibration, but also the overhang length from the outer periphery of the enlarged diameter part of the wing becomes short, so the resistance of the ground during construction is small and the threaded pile penetrates into the ground with a small torque. And a large tip supporting force can be obtained. In addition, the thickness of the enlarged diameter portion and the blades can be reduced, so that the cost can be reduced and it is economical.

(2) In the above screwed pile, the enlarged diameter portion is formed in a truncated conical shape. (3) Alternatively, since it is formed of a cylindrical body having a diameter larger than that of the pile, the same as (1) above The effect can be obtained. (4) In addition, since the enlarged diameter portion of the cylindrical body of (3) is joined to the pile body with the wing-shaped joint member, it contributes to the propulsive force and the supporting force of the pile in addition to the effect of (1). Can be.

(5) In the screw pile according to any one of (1) to (4), the blade is joined to the inner wall of the enlarged diameter portion, so that the same effect as (1) can be obtained. If the wings are mounted in a direction opposite to the direction of the penetration rotation of the screwed pile, intrusion of earth and sand into the pile body can be suppressed, and an effect of closing the tip opening can be obtained.

(6) In the method for constructing a threaded pile according to the present invention, an auger is inserted into any of the threaded piles described in (1) to (5) above, and the threaded pile is ground by the action of the auger and the wing. Since it penetrates inside, the torque of the construction machine for the penetration and the reaction force from the motor to the construction machine can be reduced.

(7) In the method for constructing a threaded pile according to the above (6), the curable fluid is jetted into the excavated and softened soil to be stirred and mixed with the earth and sand, so that the effect of the above (6) is obtained. At the same time, the disturbed ground is solidified, and a greater tip supporting force can be exhibited.

[Brief description of the drawings]

FIG. 1 is a perspective view of a screw pile according to Embodiment 1 of the present invention.

FIG. 2 is a schematic longitudinal sectional view of FIG.

FIG. 3 is a schematic longitudinal sectional view of a screw pile according to Embodiment 2 of the present invention.

FIG. 4 is a schematic longitudinal sectional view of a screw pile according to Embodiment 3 of the present invention.

FIG. 5 is a schematic longitudinal sectional view of a screw pile according to Embodiment 4 of the present invention.

FIG. 6 is an explanatory diagram of a method for constructing a threaded pile according to Embodiment 5 of the present invention.

FIG. 7 is an explanatory diagram of a method for constructing a threaded pile according to Embodiment 6 of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 screwed pile 2 pile main body 3 pile body 4, 4 a enlarged diameter portion 6, 6 a wing 7 central opening 9 joint member 9 a wing-shaped joint member 10 auger 11 auger head 13 through hole 14 spout 15 motor 18 construction machine 20 hardening material plant

Continued on the front page (72) Inventor Gen Mori 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. F-term (reference) 2D041 AA02 BA12 CA04 CA05 CB04 CB06 DB02 FA01 FA14 2D050 AA06 CA02 CA05 CB03

Claims (7)

[Claims] 1. A threaded pile that rotates a pile body provided with wings and penetrates the pile body into the ground by the action of the wing, wherein a diameter-expanding portion is provided at a tip end of the pile body, and at least the diameter-expansion is provided. A screw-in pile having wings provided at or near the tip of the part. 2. An enlarged diameter portion having a truncated conical shape in which an outer diameter of an upper end is substantially equal to an outer diameter of a pile, and an outer diameter of a lower end is larger than an outer diameter of the pile. The screwed pile according to claim 1, wherein an upper end of the enlarged diameter portion is joined to a tip of the pile body. 3. The enlarged diameter portion is formed of a cylindrical body having a diameter larger than the outer diameter of the pile body, and the enlarged diameter portion is connected to the pile body via a donut-shaped, disk-shaped or elliptical joint member. The screw-in pile according to claim 1, wherein the pile is joined to the tip. 4. The threaded pile according to claim 3, wherein the joint member is formed in a wing shape having a larger diameter than the pile body, instead of the donut-shaped, disk-shaped or elliptical joint member. 5. A screw pile according to claim 1, wherein the wing is joined to an inner wall of the enlarged diameter portion. 6. An auger is inserted into the threaded pile according to any one of claims 1 to 5 having a central opening in the wing and the joint member, and the auger head is protruded from the tip of the pile to form the auger and the wing. A method for constructing a screwed pile, wherein the screwed pile is penetrated into the ground by an action. 7. The auger head according to claim 6, wherein a through hole is provided in the axial direction of the auger, and a spout is provided in the auger head. Construction method of screwed pile.