JP2000144728A - Execution method of screw pile and screw pile used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an execution method of a screw pile and the screw pile used therefor capable of promoting efficiency of screw penetration, at the same time, greatly reducing rotational torque and obtaining high front end bearing force. SOLUTION: An execution method of a screw pile is so constituted that operation as a wood screw of a wing 10 fixed to the front end of a hollow pile body 1 and ground excavation softening operation of an auger 20 inserted into a hollow section of the pile body 1 are used to provide torque to the pile through a motor 32 to rotate the pile in the ground to penetrate. In that case, the motor 32 has two rotary shafts capable of rotating them in the opposite direction each other, one rotary shaft is connected to a pile head section, the other rotary shaft is connected to the auger head to rotate them, and hardening fluid is spouted from the auger head 22. Earth and sand and hardening fluid are stirred and mixed by the rotation of the wing 10 and auger head 22, and when stirring and mixing up to a specific depth are completed, the pile is left behind to pull out the auger 20, and earth and sand softened with the elapse of time are solidified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a threaded pile and a threaded pile used in the method, and more particularly, to a wing attached to a tip of a ready-made pile such as a steel pipe pile or a concrete pile or in the vicinity thereof. The present invention relates to a method for constructing a threaded pile that is used to rotate into a ground and thereby penetrate into the ground by acting as a wood screw of a wing, and a threaded pile used for the method.

[0002]

2. Description of the Related Art Various methods of burying steel pipe piles by applying a rotational force by a pile driver installed on the ground and acting as a wood screw attached to a tip near the tip have been proposed. Some of them are intended for small diameter steel pipe piles, but they have been put into practical use. Hereinafter, a conventional technique which is 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 into the ground, the excavation blade at the lower end excavates and softens the earth and sand at the tip of the pile body, and makes the spiral wings bite into the unexcavated earth and sand on the side of the pile. While extruding and softening the excavated softened soil to the side of the pile,
The antibody is screwed into the ground with no soil (prior art 1).

A steel pipe pile described in Japanese Patent Application Laid-Open No. 7-292666 has a pair of spiral wings, each of which has a length of half a roll and an outer diameter of about 1.5 to 3 times the pile body. A plurality of steel pipe piles are fixed discontinuously relative to each other at the same height position on the outer peripheral surface of the lower end portion of the steel pipe pile with the same helical direction (prior art 2).

[0005] Further, a rotary press-fit steel pipe pile described in Japanese Patent Application Laid-Open No. 61-98818 has a structure in which a steel cylinder is provided at a lower portion thereof.
Providing a blade having a pushing inclined front surface extending in the vertical direction, and forming an annular drill head by fixing an inclined blade obliquely rising upward from a lower end portion of the inclined front surface toward the rear in the cylindrical body rotating direction, The lower end of the steel pipe pile is attached to the upper end of the drill head (prior art 3).

In Japanese Patent Application Laid-Open No. Hei 8-226124, spiral blades are provided on the outer peripheral surface near the tip of a steel pipe pile, and open ribs are provided on the inside of the steel pipe above the tip to promote the blockage of earth and sand. A pile having a perforated tubular portion and a method of burying the same are described. This technology aims to reduce the torque by allowing earth and sand to enter the steel pipe at the time of construction, and to close the earth and sand in the perforated tubular part to form a support bottom and secure the tip support force. (Prior Art 4).

In the method of burying steel pipe piles described in Japanese Patent Application Laid-Open No. 4-58850, the lower end of the steel pipe pile is closed with a bottom plate having a cutting blade and a grout outlet, and the outer diameter of the steel pipe is almost twice as large. Spiral wings with an outer diameter of approximately one turn fixed to the outer peripheral surface of the lower end of the steel pipe pile almost in one turn, and cement milk is spouted from grout injection holes during and after burial to strengthen the surrounding ground (Prior Art 5).

[0008]

The steel pipe pile according to the prior art 1 has been widely put into practical use with a steel pipe diameter of less than 300 mm. A relatively large tip supporting force can be secured because the tip of the steel pipe is closed by the bottom plate, but the torque required for rotation penetration becomes extremely large because the spiral blade receives a large reaction force from the ground. The penetration efficiency becomes worse. According to several field tests conducted by the inventor, the torque required to penetrate the support layer increases to 3 to 5 times the torque when penetrating the soft ground. For this reason, a motor with a large capacity to rotate the antibody and a base machine to mount it are required, and the torsion moment of the pile body becomes large, and a steel pipe with a thickness larger than the design required is required. Often required for construction. Also, it cannot be applied to concrete piles that are vulnerable to torsion. The steel pipe diameter is 600
If it exceeds mm, the torque becomes too large and a special large-sized machine is required, which is not practical. Further, the hard support layer is disturbed by the spiral blade and the excavation blade for improving excavation efficiency at the time of rotation penetration, and a soft soil layer is formed immediately below the blade, so that the support force inherent in the support layer cannot be exhibited.

[0009] In the steel pipe pile of the prior art 2, whether or not a bottom plate is attached to the tip of the pile is not limited. In the case where the bottom plate is attached, there is the same problem as in the prior art 1. In addition, when the bottom plate is not attached, since the soil enters the pile body, the torque required for the rotation penetration does not increase so much. However, because the pile tip is open and the support layer ground is agitated by the spiral wing,
Large tip support force cannot be obtained.

[0010] The steel pipe pile of the prior art 3 has a small rotating torque at the time of construction because the width of the inclined blade is narrow, but has a low penetration efficiency due to a small propulsive force for rotational penetration. Further, since the outer diameter of the wing is small and the stake is an open-end stake, a large tip support force cannot be obtained as in the prior art 2.

The steel pipe pile according to the prior art 4 has an open end to reduce the rotational torque and improve the penetration efficiency, and to provide a perforated tubular portion so that the soil in the support layer can be removed from the perforated tubular portion. This is intended to obtain a large tip supporting force by obtaining a closing effect by staying at the end. However, in order to obtain a sufficient closing effect when the support layer penetrates, it is necessary to make the inner diameter of the opening rib sufficiently small so that the earth and sand in the perforated cylindrical portion does not move upward. In this case, actually, the same state as when the pile tip is closed with the bottom plate, that is, the penetration efficiency is deteriorated and the rotational torque has to be increased. Other techniques of this type have been proposed but are not practical.

Further, in the method of embedding the steel pipe pile according to the prior art 5, since the cement milk is jetted from the tip and mixed with the earth and sand by the spiral blade, the turbulence of the support layer ground due to the spiral blade is somewhat recovered. However, since the rotation for stirring and mixing is only in one direction of the spiral blade, sufficient stirring of earth and sand and cement milk cannot be expected. In particular, when the ground is a viscous soil, the stirring and mixing tend to be uneven. Further, although the rotation torque can be slightly reduced as compared with the case where the cement milk is not ejected, a sharp reduction in torque cannot be expected because the tip of the pile is blocked and earth and sand near the tip of the pile is difficult to move.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and improves the efficiency of screw-in penetration and greatly reduces the rotational torque. It is an object of the present invention to provide a method for constructing a screwed pile capable of obtaining a force and a screwed pile used for the method.

[0014]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for constructing a threaded pile according to the present invention, in which the hollow pile has a function as a wood screw fixed to the tip or near the tip of the hollow pile. Utilizing the ground excavation softening action of the inserted auger, a construction method of applying a rotational force to a pile head and an auger head by a motor mounted on a pile driver and rotating the pile into the ground by rotating the pile, The motor has two rotating shafts that can rotate in opposite directions, connecting one rotating shaft to the pile head, connecting the other rotating shaft to the auger head to rotate each, During the rotation of the pile, a curable fluid is ejected from the auger head into a support layer or a desired section including the support layer, and the sand and the curable fluid are stirred and mixed by rotation of the wing and the auger head. When the stirring and mixing is completed to the depth of The pull out the auger by leaving a pile, in which so as to solidify the softened sediment over time.

The method for constructing a threaded pile according to the present invention is characterized in that the wing is fixed to the tip of the hollow pile or at the vicinity of the tip by using a wood screw, and the auger inserted into the hollow of the pile is provided. Using the ground excavation softening effect of the above, the pile rotation motor mounted on the pile driving machine gives a rotational force to the body of the pile, and the auger head mounted on or near the pile head uses the auger rotation motor. A method of applying a rotational force to a portion to rotate and penetrate the pile into the ground, wherein the pile rotation motor and the auger rotation motor can rotate in opposite directions to each other, and during rotation of the pile, A curable fluid is ejected from the auger head to a desired section including the support layer or the support layer, and the slag and the auger head are rotated to mix and mix the earth and sand with the curable fluid, and the mixture is stirred and mixed to a predetermined depth. When completion is pulling the auger by leaving a pile, in which so as to solidify the soil softened over time.

[0016] In any of the threaded pile construction methods described above, when the tip of the pile penetrates the hard stratum, the auger is rotated in a direction to push up the earth and sand, and when the pile penetrates the soft stratum, Stop auger rotation,
Or it was made to rotate in the direction of pushing down the earth and sand.

[0017] In any one of the above-described screw pile mounting methods, the outer diameter of the auger head is larger than the outer diameter of the tip of the pile, and can be expanded within a range substantially equal to or less than the outer diameter of the blade. It was used.

In the threaded pile according to the present invention, a wing composed of a spiral or a plurality of flat plates is fixed to the tip of the pile body or an outer periphery near the tip, and the wing has an outer diameter of one end of the pile tip. .
It has an outer diameter of 3 to 2.0 times and is configured so that the sum of its inner angles is 330 to 360 °, and is constructed by any of the above construction methods.

Further, in the threaded pile according to the present invention, a wing composed of a spiral or a plurality of flat plates is fixed to the tip of the pile or at the outer periphery near the tip, and the outer diameter of the upper part of the pile is the pile. It is configured to be larger than the outer diameter of the lower part and equal to or less than the outer diameter of the wing, and is constructed by any one of the construction methods described above.

[0020]

[First Embodiment] FIG. 1 is a schematic diagram for explaining a first embodiment of the present invention. In the figure, reference numeral 1 denotes a prefabricated pile (hereinafter referred to as a pile body) having a hollow and circular cross section, such as a steel pipe pile or a concrete pile. 1
0 constitutes a threaded pile. Reference numeral 20 denotes an auger inserted into the pile 1, and reference numeral 30 denotes a base machine, which is a pile driver installed on the ground, provided with two rotating shafts (an outer shaft and an inner shaft) that rotate in opposite directions. The motor 32 is mounted.

The pile 1 has an opening at the tip, and a wing 10 is attached to the outer periphery slightly above the tip. As shown in FIG. 2, the wing 10 is formed by fixing a spiral wing 11 formed by bending a donut-shaped steel plate to the pile body 1 by welding or the like, and an opening is provided between the start end and the end. A stepped portion 12 is formed.

In the axial direction of the auger 20, there is provided a through-hole 21 for pressure-feeding a curable fluid such as cement milk or a liquid for solidifying the ground to the distal end portion. An ejection port 23 for ejecting the curable fluid is provided at 22. A spiral blade 24 is provided above the auger head 22 and has a function of pushing up or pushing down earth and sand. Numeral 40 designates a plant for hardening fluid such as cement milk or soil hardening liquid (hereinafter referred to as hardening material plant). The auger 20 is rotatably connected to a through hole 21 provided in the auger 20 by a hose 41. I have.

Next, an example of the construction method of the present embodiment configured as described above will be described with reference to FIGS. In addition,
3 and 4 show the base machine 30 and the hardening material plant 4.
0 is omitted. (1) As shown in FIG. 3A, an auger 20 slightly longer than the pile 1 is inserted into the pile 1. In the case where the area for solidifying the ground described below is only the support layer due to design, the pile 1 penetrates into the ground, and the auger 20 is inserted into the pile 1 when the tip of the pile reaches the vicinity of the support layer. May be inserted.

(2) As shown in FIG. 5, the pile head of the pile 1 is connected to the outer shaft 33 of the motor 32, and the head of the auger 20 is connected to the inner shaft 34. When the design pile head position is below the construction ground surface and a yatco is used, the outer shaft 33 is connected to the upper part of the yatco. Further, the hose 41 of the hardening material plant 40 is connected to the through hole 21 of the auger 20 via a rotatable joint (not shown). At this time,
The tip (auger head 22) of the auger 20 is shown in FIG.
As shown in (a), it protrudes from the tip of the pile 1,
It is desirable that the protrusion length is approximately equal to or less than the outer diameter of the wing 10.

(3) By the motor 32, for example, the pile 1 is rotated in the forward direction and the auger 20 is rotated in the reverse direction. As a result, as shown in FIG.
2 excavates and softens the ground near the tip ahead of the pile 1
The pile 1 is penetrated into the ground by the action of a wood screw on the wing 10. At this time, the earth and sand near the tip of the pile 1 passes through the step 12 of the wing 10 and moves to the outer periphery of the pile 1 above the wing 10, and part of the earth and sand is transferred to the spiral blade 24 of the auger 20. Is taken into the pile 1.

The amount of sediment taken into the pile 1 by the auger 20 varies depending on the size of the opening of the tip of the pile 1 and the size and shape of the auger head 22. Do not overflow from one. In this case, the torque decreases as the amount of sediment taken into the pile 1 increases. In addition, as the amount of sediment taken in the pile body 1 is smaller, the density of the earth and sand around the pile body 1 becomes higher, and a larger peripheral surface friction force is exerted.

When the pile 1 penetrates, the ground required for excavation and softening of the ground ahead of the wings 10 by the auger head 22 is significantly larger than that required when the auger 20 is not used. Decrease. Further, since the rotation directions of the pile 1 and the auger 20 are opposite to each other, the reaction force from the motor 32 acting on the base machine 30 also becomes a reaction force due to a difference between the two torques, and thus is greatly reduced.

(4) When the pile body 1 has penetrated to an appropriate depth, the hardening material plant 40 is driven and the hardening material flows into the through hole 21 of the auger 20 via the hose 41 as shown in FIG. The animal 42 is pumped and spouted from the spout 23 provided at the tip of the auger head 22, and the auger head 2
2 and the earth and sand softened by the rotation of the blades 10 are mixed by stirring. At this time, since the rotation directions of the pile 1 and the auger 20 are opposite, the curable fluid 42 and the earth and sand are well stirred to form a highly uniform mixture 50. The ejection section of the curable fluid 42 is determined according to the peripheral friction of the pile body 1 necessary for design, and may be the entire section from the pile head to the pile tip or in the vicinity of the pile tip. Or just

(5) When the tip of the pile reaches the support layer,
As shown in FIG. 4A, the wing 10 and the auger head 22
The supporting layer is sufficiently stirred by the
After that, the rotation of the pile 1 and the auger 20 is stopped. (6) Then, as shown in FIG. 4B, the pile 1 is removed from the motor 32, and the motor 32 is raised while rotating the auger 20 in the opposite direction while the pile 1 is left under the ground. In this case, the auger 20 is pulled up from the pile 1, and the pile 1 is buried in the ground, and the construction is completed.

The method for constructing a threaded pile according to the present embodiment is for rotating the pile 1 in order to preliminarily excavate the ground near the tip of the pile with the auger head 22 of the auger 20 inserted into the pile 1. The torque can be reduced, whereby the penetration efficiency of the pile 1 is improved, and the auger 20 and the base machine 30 can be downsized.
Further, since the torsional moment acting on the pile 1 is small, the threaded pile can be applied to a thin steel pipe pile or a concrete pile that is vulnerable to torsion. Further, the present invention can be applied to a large pile body having an outer diameter exceeding 600 mm, which has conventionally been considered difficult to screw.

Further, the curable fluid 42 ejected from the tip of the auger 20 and the earth and sand are agitated and mixed, so that the disturbed ground is solidified, so that a large tip supporting force can be exhibited. Further, the wing 10 and the auger 20 can rotate in opposite directions, so that the hardenable fluid 42
And earth and sand are evenly mixed.

Also, as described above, the pile 1 and the auger 20
Can rotate in directions opposite to each other, the respective torques cancel each other, and the reaction force acting on the base machine 30 from the motor 32 can be reduced. Therefore, even if the base machine 30 is downsized, it is stable. Nature can be secured.

[Embodiment 2] FIG. 6 is an explanatory diagram of this embodiment. 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, a pile body rotation motor 35 for rotating the pile body 1 is provided below the reader 31 of the base machine 30 and attached to the body of the pile body 1. 3
An auger rotation motor 36, which is hung from 1 and rotates the auger 20, is disposed at or near the pile head.

The operation of the present embodiment is almost the same as that of the first embodiment, except that the auger rotating motor 36 is replaced by the motor 32 having two rotating shafts shown in the first embodiment.
It can be smaller and lighter. Therefore, the weight of the object (motor) arranged at a high position is reduced, so that the stability of the base machine 30 can be increased.

In the above description, the case where the auger rotation motor 36 is hung from the head of the reader 31 of the base machine 30 has been described, but the auger rotation motor 36 is fixed to the pile head of the pile body 1. The pile body 1 may be used as a reaction force body to apply a rotational force to the auger 20. With this configuration, the length of the reader 31 can be shortened, and the torque acting on the base machine 30 is further reduced, so that the base machine 30 can be downsized.

[Embodiment 3] FIG. 7 shows an example of ground conditions from the ground surface to the support layer. Hereinafter, a pile body is penetrated into this ground by the construction method according to Embodiment 1 or 2. A method for constructing a screwed pile according to the present embodiment will be described. In FIG. 7, the upper soft layer near the ground surface is
Since the penetration resistance acting on the wing 10 and the pile body 1 is small, it is not necessary to soften the ground by the auger head 22.
For this reason, the rotation of the auger 20 is stopped and the pile 1 penetrates only by rotation.

At this time, the soil softened by the wing 10
Pile 1 interrupted by spiral blade 24 of auger 20
Hardly penetrates into the inside, moves through the step portion 12 of the wing 10 to the periphery of the pile body 1 and is compressed into high-density soil. As a result, a large peripheral frictional force and a horizontal resistance are designed. Can be expected.

Since the intermediate sand layer is relatively hard and requires a large torque to penetrate only by rotating the pile 1, the auger 20 is simultaneously rotated to excavate and soften the ground. In this case, the auger 20 rotates the ground in a direction to push down the ground. As a result, most of the excavated and softened soil does not enter the pile 1, but moves around the pile 1 through the step 12 of the wing 10.

Since the support layer is very hard, soil and sand are actively taken into the pile 1 to increase the penetration efficiency and reduce the torque. Of course, the auger 20 is rotated in a direction to push up the earth and sand. In the support layer, a large amount of earth and sand is taken into the pile body 1. However, since the earth and sand softened by the curable fluid is solidified, there is no problem in supporting force. As described above, in the present embodiment, the presence or absence of rotation of the auger 20 and the direction of rotation are adjusted according to the ground conditions,
It is possible to control the intrusion of earth and sand into the pile body and control the penetration efficiency.

[Fourth Embodiment] FIG. 8 is a schematic diagram of a main part of a fourth embodiment of the present invention. In the present embodiment, the auger head 22 of the auger 20 inserted into the pile 1 has a structure that can be enlarged by an operation from the ground or the like. In this case, enlargement of the auger head 22 corresponds to the pile 1
It is desirable that the outer diameter be equal to or larger than the outer diameter of the blade 10 and substantially equal to or smaller than the outer diameter of the blade 10.

The construction method of this embodiment is also the same as that of the first to third embodiments.
3, but the auger head 22 is
The auger 20 may be expanded from the beginning after protruding from the tip of the pile inserted into the pile 1, or may be expanded when the tip of the auger 20 reaches the vicinity of the support layer. In this case, by reducing the amount of protrusion of the auger head 22 from the tip of the pile as much as possible, the stirring and mixing efficiency of the curable fluid and the earth and sand can be increased. When the embedding of the pile 1 is completed, the auger head 2
2 is returned to its original state, the pile 1 is left underground, and the auger 20 is pulled up.

In this embodiment, the same effect as in the first embodiment can be obtained. However, since the range in which the earth and sand is excavated and softened by the enlarged auger head 22 is widened, the pile 1 is rotated. Required torque can be further reduced. In addition, as shown in FIG. 9, the sediment below the wing 10 and the sediment above the wing 10 that are disturbed by the wing 10 are solidified by the hardening fluid, so that the support ability of the support layer 51 is sufficiently exhibited. Therefore, the tip support force can be further improved.

[Fifth Embodiment] FIG. 10 is a perspective view showing a main part of the present embodiment, and FIG. 11 is a bottom view thereof. In the figure, reference numeral 10 denotes a spiral wing, which is fixed to a portion of the pile 1 at a diagonally cut end. Outer diameter D of wing 10
₁ is a 1.3 to 2.0 times the outer diameter D ₂ of Kuitai 1, interior angle of the blade 10 when viewed from above 330 ° to 360 °
In the range. The inner diameter D _{3 of the} wing 10 is smaller than the outer diameter D ₂ of the pile 1, but is larger than the outer diameter of the auger head 22.

Generally, the outer diameter of the wing of the screwed pile is in the range of about 1.5 to 2.5 times the outer diameter of the pile, but in the construction method shown in Embodiments 1 to 4, Since the curable fluid is ejected around the portion to solidify the softened earth and sand, the supporting force per unit area of the blade 10 increases. As a result,
Even if the area of the wing 10 is small, a sufficiently large supporting force can be secured. In this case, if the outer diameter D ₁ of the wing 10 is less than 1.3 times the outer diameter D ₂ of the pile body 1, the penetration function as a wood screw is reduced, the supporting force is reduced, and the economic efficiency is reduced. The outer diameter D ₁ of the wing 10 is equal to the outer diameter D ₂ of the pile 1.
Exceeding the doubling is unnecessary in design, and the thickness of the upper wing 10 becomes very thick, which increases the manufacturing cost.

Conventionally, the internal angle of the wing was 360 °, but in the case of a large-grain ground such as a boulder, the gravels cannot pass through the step 12 of the wing, and the workability deteriorates. . According to the present embodiment, the wing 10
By adjusting the inner angle of the slab, construction can be easily performed even on gravel ground. In this case, the sum of the inner angles of the wing 10 is 330
When the angle is less than 360 °, the supporting force decreases. When the angle exceeds 360 °, the resistance when earth and sand pass through the step portion 12 of the wing 10 increases.

FIGS. 12 to 15 show the wing 1 according to this embodiment.
0 shows another example. In the example shown in FIG. 12, a doughnut-shaped circular steel plate is divided into two parts from the center to form a flat steel wing 13.
a, 13b are formed, and the steel blades 13a, 13b are spirally and continuously fixed to the outer periphery of the tip of the pile body by welding to form the blade 10. In the example shown in FIG. 13, the tip of the pile 1 is divided into two parts, and mounting parts are provided, each of which is inclined in the same direction, and the steel wings 13a and 13b are fixed to the mounting parts.

The example shown in FIG. 14 is different from the example shown in FIG. 13 in that holes formed in the central portions of both steel blades 13a and 13b have an outer diameter smaller than the inner diameter of the pile 1 and an inner diameter outside the auger head 22. A cylindrical member 14 larger than the diameter is attached by welding to increase the stability of both steel wings 13a and 13b. In the example of FIG. 15, a helical portion or a two-divided sloping portion is formed at the tip end of the pile body 1, and the sloping portion is inclined along the same direction. The spiral wing 11 or the steel wings 13a and 13b are fixed. The example of the wing 10 provided on the pile 1 according to the present invention has been described above, but the present invention is not limited to this, and a wing having another shape or structure may be provided on the pile.

[Sixth Embodiment] FIG. 16 is a front view of an example of a pile body according to the present embodiment. The pile body 1 according to the present embodiment is configured such that the outer diameter of the upper pile body 1a is larger than the outer diameter of the lower pile body 1b and equal to or less than the outer diameter of the wing 10, and the upper pile body 1a
And a lower portion 1b of the pile body are connected via a short tapered tube 1c. Then, at the tip of the lower portion 1b of the pile, FIG.
Although two substantially semicircular steel wings as shown in Fig. 1 are mounted crosswise to form the wing 10, wings of other structures may be provided. The method of constructing a pile according to the present embodiment is almost the same as in the first to fourth embodiments.

When the horizontal force acting on the pile during an earthquake is large, when the ground near the ground surface is very soft, or when the ground liquefies during an earthquake, a large bending moment acts on the upper part of the pile. At the same time, the horizontal displacement increases. Under these conditions, it is more economical to use a pile with an enlarged outer diameter at the upper part of the pile (enlarged head pile) than to increase the thickness and strength of the upper part of the pile. It is well known that In fact, head cast piles are heavily used in cast-in-place concrete piles. But,
In the field of prefabricated piles, several attempts have been made in the past, but they have not been fully commercialized. The biggest reason is that even if a pile can be manufactured, a large penetration resistance occurs at a portion where the pile diameter changes (expanded portion) at the time of construction, which makes the construction difficult.

However, by using the construction methods of Embodiments 1 to 4, the head enlarged pile according to this embodiment can be easily put into practical use. Because the pile 1
Is excavated and softened by the wings 10 having an outer diameter larger than the outer diameter of the pile body upper portion 1a, and is compressed to increase the pore water pressure of the soil. For this reason, a large penetration resistance is not received even in the enlarged diameter portion.

FIG. 17 is a front view showing another example of the pile body according to the present embodiment, in which an upper pile body 1a and a lower pile body 1b are joined via a circular steel plate 1d to form an enlarged head pile 1. It is composed. The inventor of the present invention attached a steel wing with an outer diameter of 1000 mm at the tip to a 508 mm outer diameter winged steel pipe (lower part 1b of a pile body) at the upper end thereof to a thickness of 40 mm and an outer diameter of 80 mm.
A steel pipe having an outer diameter of 800 mm (upper part 1a of the pile body) was joined via a 0 mm circular steel plate 1d to produce a 43 m-long threaded pile, and a test was conducted to investigate workability on actual ground.
As a result, it was confirmed that the construction efficiency was almost the same as the construction efficiency of a screw-in pile with a wing having an outer diameter of 508 mm.

The pile 1 shown in FIG. 18 has a projection 3 provided by welding a reinforcing bar or angle steel to the inner wall surface of the pile 1 by welding or the like. The adhesive force of the mixture with the fluid on the inner surface of the pile 1 is enhanced, and the supporting force at the tip is more ensured. The range in which the projections 3 are provided is 1/1 / the outer diameter D of the pile 1 from the tip of the pile 1.
A range of about 2 to 2 times is desirable.

[0053]

According to the first aspect of the present invention, there is provided a method of constructing a threaded pile, wherein the hollow pile has an auger inserted into a hollow portion of the pile, the action being a wood screw fixed to a tip portion or a vicinity of the tip portion. By utilizing the softening effect of the ground excavation, the pile can be rotationally penetrated into the ground with a small torque, and the screwing method can be applied to a large-diameter pile. In addition, since the two rotating shafts of the motor for rotating the pile body and the auger can be rotated in opposite directions, the torque acting on the pile driver can be reduced, and as a result, the pile driver can be reduced in size. Can be Furthermore, a large supporting force can be obtained by stirring and mixing the curable fluid and earth and sand ejected from the auger head with the wings and the auger head and solidifying the same. Further, by rotating the pile body and the auger head in opposite directions, the curable fluid and the earth and sand can be uniformly stirred and mixed.

According to a second aspect of the present invention, there is provided a method for constructing a threaded pile, wherein a pile rotating body mounted on a pile driver applies a rotating force to a body of the pile, and an auger disposed at or near a pile head. Since the rotating motor applies a rotating force to the auger head, the same effect as in the first aspect is obtained, and the stability of the pile driver can be enhanced.

According to a third aspect of the present invention, there is provided a method for constructing a threaded pile.
By adjusting the rotation or rotation direction of the auger in accordance with the ground conditions, the intrusion of the earth and sand into the pile body and the control of the penetration efficiency are performed, so that the workability can be improved.

According to a fourth aspect of the present invention, there is provided a method for constructing a threaded pile,
Since the auger head, which is larger than the outer diameter of the pile and can be expanded in a range approximately equal to or less than the outer diameter of the wing, is used, the rotation torque of the pile can be further reduced, and the supporting force is increased. can do.

In the screwed pile according to the fifth aspect, the outer diameter of the wing is in the range of 1.3 to 2.0 times the outer diameter of the pile body, so that good workability, bearing capacity and economy can be achieved. In addition, by setting the sum of the inner angles of the wings in the range of 330 to 360 °, it is possible to easily perform construction even on a gravel ground having a large particle size, and the supporting force is not reduced.

In the threaded pile according to the sixth aspect, the outer diameter of the upper portion of the pile is larger than the outer diameter of the lower portion of the pile, and is equal to or less than the outer diameter of the wing. Partial expansion piles can be constructed, and the horizontal resistance during an earthquake can be increased.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for describing Embodiment 1 of the present invention.

FIG. 2 is an explanatory view of a tip end of a pile body of FIG. 1;

FIG. 3 is an explanatory diagram of a construction method according to the first embodiment.

FIG. 4 is an explanatory diagram of a construction method according to the first embodiment.

FIG. 5 is a schematic diagram showing a connection state of a motor, a pile body, and an auger according to the first embodiment.

FIG. 6 is an explanatory diagram of Embodiment 2 of the present invention.

FIG. 7 is an explanatory diagram of a third embodiment of the present invention.

FIG. 8 is an explanatory diagram of a main part of a fourth embodiment of the present invention.

FIG. 9 is an explanatory diagram showing a construction result of the fourth embodiment.

FIG. 10 is a perspective view of a main part according to a fifth embodiment of the present invention.

FIG. 11 is a bottom view of FIG. 10;

FIG. 12 is a perspective view of another example of the fifth embodiment.

FIG. 13 is a perspective view of another example of the fifth embodiment.

FIG. 14 is an explanatory diagram of another example of the fifth embodiment.

FIG. 15 is an explanatory diagram of another example of the fifth embodiment.

FIG. 16 is an explanatory diagram of Embodiment 6 of the present invention.

FIG. 17 is an explanatory diagram of another example of the sixth embodiment of the present invention.

FIG. 18 is an explanatory diagram of another example of a pile body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pile body 1a Pile body upper part 1b Pile body lower part 3 Convex part 10 Blade 11 Spiral wing 12 Step part 13a, 13b Steel wing 20 Auger 21 Through hole 22 Auger head 23 Spout port 24 Spiral blade 30 Base machine 32 Motor 33 Pile Body rotation motor 34 Auger rotation motor 40 Hardener plant 42 Hardenable fluid 50 Mixture of earth and sand and hardenable fluid

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hisashito Shimaoka 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Kokan Co., Ltd. (72) Inventor Gen Gen 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Kokan Co., Ltd. (72) Inventor Masahiro Hayashi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Takashi Okamoto 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon (72) Inventor Kazuomi Ichikawa 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Japan Tube Co., Ltd.

Claims (6)

[Claims] The present invention relates to a method of manufacturing a pile using a wood screw having a wing fixed at or near the tip of a hollow pile, and a softening action of an auger inserted into the hollow of the pile. A method of applying a rotational force to a pile head and an auger head by a motor mounted on a hammer to rotate and penetrate a pile into the ground, wherein the motors can rotate in opposite directions to each other. Having a rotation axis, one rotation axis connected to the pile head, the other rotation axis connected to the auger head to rotate each, and preferably includes a support layer or a support layer during the rotation penetration of the pile. The curable fluid is ejected from the auger head in the section of the above, the earth and sand and the curable fluid are stirred and mixed by rotation of the wing and the auger head, and when the stirring and mixing is completed to a predetermined depth, the pile is left. Pull out the auger and over time A method for constructing screwed piles, comprising solidifying softened earth and sand. 2. A pile using a function as a wood screw of a wing fixed to a tip portion or a vicinity of a tip portion of a hollow pile body and a soil excavation softening action of an auger inserted into a hollow portion of the pile body. The pile rotating motor mounted on the hammer gives a rotating force to the body of the pile, and the auger rotating motor placed on or near the pile head applies a rotating force to the auger head to place the pile in the ground. A method of rotating and penetrating, wherein the pile rotation motor and the auger rotation motor can rotate in opposite directions to each other, and auger a desired section including a support layer or a support layer during rotation of the pile. The hardening fluid is ejected from the head, and the wings and the auger head rotate to mix and mix the earth and sand with the hardening fluid. When the stirring and mixing is completed to a predetermined depth, the pile is left and the auger is pulled out. A method for constructing a threaded pile, comprising solidifying soil softened over time. 3. When the tip of the pile penetrates a hard stratum, the auger is rotated in a direction to push up the earth and sand. When the tip of the pile penetrates a soft stratum, the rotation of the auger is stopped. 3. The method for constructing a screwed pile according to claim 1, wherein the pile is rotated in a direction in which the screw is pushed downward. 4. An auger wherein the outer diameter of the auger head is larger than the outer diameter of the tip of the pile, and which can be expanded in a range substantially equal to or less than the outer diameter of the wing. The construction method of the screwed pile according to 2 or 3. 5. A method according to claim 1, further comprising the step of:
A wing composed of a spiral or a plurality of flat plates is fixed, and the wing has an outer diameter of 1.3 to 2.0 times the outer diameter of the tip of the pile, and the sum of its inner angles is 330 to 360 °. A threaded pile constructed by the construction method according to any one of claims 1 to 4. 6. The tip of the pile or an outer periphery near the tip of the pile,
A wing composed of a spiral or a plurality of flat plates is fixed, and an outer diameter of an upper part of the pile is larger than an outer diameter of a lower part of the pile and less than or equal to an outer diameter of the wing. A screw pile, which is constructed by the construction method described in (1).