JPH1121885A - Screw-in type steel pipe pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw-in type steel pipe pile capable of generating a large plumb supporting force which can fabricate easily at a low cost, steel plates to constitute a lower and an upper blade, can reduce the labor and cost required to install the lower and upper blades to the steel pipe, and enables penetration at a pitch near the value decided by the dimensions and shapes of the lower and upper blades even in case it is applied to a hard ground. SOLUTION: A blade fixed to a steel pipe is structured so that sector-shaped steel plates 10a-10c formed by dividing a doughnut-shaped steel plate having a greater outside diameter than the steel pipe 2 are attached spirally to the outside surface near the forefront of a steel pipe pile 1 or is equipped with lower blades 10 installed as inclined in the same direction and same angle at the same level on the outside surface near the forefront of the steel pipe pile 1. Steel plates 20a-20c of such a structure as similar to the steel plates 10a-10c of the lower blades 10 are attached spirally in the same direction as the lower blades 10a-10c to the outside surface near the middle part in the longitudinal direction of the steel pipe pile 1 or is formed along with the upper blades 20 attached as inclined in the same direction and angle as the lower blades 10a-10c at the same level on the outside surface near the middle part in the longitudinal direction of the steel pipe pile 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw-in type steel pipe pile, and more particularly, to a steel pipe pile in which a lower blade is attached at or near a tip end of a steel pipe and an upper blade is attached near an intermediate portion in a longitudinal direction. The present invention relates to a screw-in type steel pipe pile which is buried underground by applying a rotational force to the steel pipe pile by a screw action.

[0002]

2. Description of the Related Art A screw-in type that is buried underground by the action of a screw by applying a rotating force to a steel pipe pile having a spiral wing or the like attached to the tip or side of the steel pipe by a driving device installed on the ground. Many steel pipe piles have been proposed,
Some of them are intended for small diameter piles, but they have been put into practical use. Hereinafter, an example of this type of threaded steel pipe pile 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 pile body is screwed into the ground without earth removal (prior art 1).

In the foundation pile described in Japanese Patent Application Laid-Open No. 63-161219, a screw blade-like excavating blade is continuously or intermittently longitudinally integrated with the tip and outer periphery of a pile body made of a vertically long steel pipe. (Prior Art 2).

In the pile described in Japanese Patent Publication No. 5-42524, a helical excavator blade or excavator screw is provided at the tip of a pile body having a sharp tip, and the tip is formed at the rear end. The pressure fin or the pressure screw formed with a screw pitch smaller than the screw pitch of the spiral digging blade or the digging screw provided is provided (prior art 3). The inclined blades and the like shown in these prior arts 1 to 3 function not only as screws during construction, but also as a support for obtaining a large ground support force.

[0006]

According to the prior art 1, the penetration pitch per rotation at the time of screwing construction is substantially the same as the pitch determined by the shape and dimensions of the spiral blade in the case of soft ground. However, since the wing is a single-stage spiral wing with almost one turn, the pitch is smaller than this in the ordinary ground. In particular, the penetration pitch is significantly reduced when reaching a solid support layer. Therefore, the construction time required for screwing is increased, and the ground around the spiral blade is disturbed and softened, so that a large vertical support force cannot be obtained. In addition, the spiral wings are formed by bending a flat plate into a spiral shape, which not only takes time and effort to manufacture, but also has a dimensional error during manufacture between the spiral wings and the steel pipe. Insertion work and welding work of the spiral blade and the steel pipe require a lot of labor and cost.

Next, in the prior art 2, since the screw blades are provided continuously or intermittently, the problem of the penetration pitch unlike the prior art 1 does not occur. It is dug out and cannot expect a great bearing capacity. In addition, the manufacturing cost of the screw blade must be very high, and the work of inserting the steel pipe into the screw blade and the welding work of the screw blade and the steel pipe are more difficult than the prior art 1, In practice, implementation is almost impossible.

Further, when the prior art 3 is applied to a steel pipe pile, there are the same problems as in the case of the prior art 1 in the production of the excavator blade, the insertion of the pile, and the welding work with the pile. Furthermore, a pressure impeller attached to the rear end of the pile is not practically useful. That is, since the pressure impeller is not a screw impeller, the earth and sand are not actually dug out. Further, since the pitch is smaller than the pitch of the excavator blade, the effect of increasing the penetration pitch of the pile body cannot be expected at all.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is easy and inexpensive to manufacture steel plates constituting the lower and upper wings, and it is necessary to attach the lower and upper wings to a steel pipe. A screw-in type steel pipe pile that can reduce labor and cost, penetrate even on hard ground at a pitch close to the pitch determined by the dimensions and shape of the lower and upper wings, and provide a large vertical bearing capacity It is intended for.

[0010]

[Means for Solving the Problems]

(1) The screw-in type steel pipe pile according to the present invention is characterized in that a wing attached to the steel pipe is divided into a plurality of donut-shaped steel plates whose outer diameter is larger than the outer diameter of the steel pipe. Lower wing attached spirally to the outer peripheral surface in the vicinity of the portion, or attached at the same height position on the outer peripheral surface near the tip of the steel pipe pile in the same direction and at the same angle, and the steel plate of the lower wing A steel plate having a similar structure is helically attached to the outer peripheral surface near the middle part in the longitudinal direction of the steel pipe pile in the same direction as the lower blade, or the same height of the outer peripheral surface near the middle part in the longitudinal direction of the steel pipe pile. The upper wing is mounted at the same position as the lower wing in the same direction and at the same angle.

(2) In the screw-in type steel pipe pile according to the present invention, the tip portion is spirally cut to form an attachment portion, or the tip portion is divided into a plurality of pieces in the circumferential direction, and the divided individual pieces are divided. And a steel plate in which a circular steel plate whose outer diameter is larger than the outer diameter of the steel pipe is divided into a plurality of pieces, and a steel pipe having an R-shaped mounting part formed in the same direction in the same direction is mounted on the mounting part of the steel pipe. A lower-stage wing and a fan-shaped steel plate obtained by dividing a donut-shaped steel plate having an outer diameter larger than the outer diameter of the steel pipe into a plurality of pieces are provided on the outer peripheral surface near an intermediate portion in a longitudinal direction of the steel pipe pile. With the upper wing attached to the lower wing in the same direction and at the same angle at the same height position on the outer peripheral surface near the middle part in the longitudinal direction of the steel pipe pile. It is.

(3) Further, in the screw type steel pipe pile according to the above (1) or (2), the pitch per rotation of the upper blade is formed larger than the pitch per rotation of the lower blade. (4) In the screw-in type steel pipe pile of (1), (2) or (3), the outer diameter of the upper blade is formed larger than the outer diameter of the lower blade.

[0013]

FIG. 1 is a perspective view of a screw-in type steel pipe pile according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. In the figure, 1
Is a steel pipe pile (hereinafter simply referred to as a steel pipe pile), and 2 is a steel pipe constituting the steel pipe pile 1. Reference numeral 10 denotes a lower wing attached to the outer periphery of the steel pipe 2 in the vicinity of the front end of the steel pipe 2, that is, slightly above the outer periphery of the front end of the steel pipe 2 or slightly above the front end. For example, an upper blade attached to the outer periphery of the steel pipe 2 in the vicinity of an intermediate portion in the longitudinal direction of the steel pipe pile 1.

As shown in FIG. 3, the outer diameter D _{1 of the} lower blade 10 is larger than the outer diameter d of the steel pipe 2 (for example, D ₁ = 2).
d) a steel plate 10 composed of a fan-shaped flat plate obtained by dividing a donut-shaped steel plate into three equal parts, the inner diameter D _{2 of} which is substantially equal to the outer diameter d of the steel pipe 2.
a, 10b, and 10c are joined to the outer peripheral surface of the distal end portion (lower end portion) of the steel pipe 2 or the outer peripheral surface slightly above the distal end portion by welding so as to be spirally formed as a whole. .

The upper wing 20 is made of steel plates 20a, 20b, 20a, 20b, and 20c having a structure corresponding to the steel plates 10a to 10c of the lower wing 10.
20c is helically welded between the lower wing 10 and the upper end of the steel pipe pile 1, for example, at the outer peripheral surface near the longitudinal middle part of the steel pipe pile 1 at the same angle as the steel plates 10a to 10c by welding. It was done. The size of the lower wing 10 and the upper wing 20 differs depending on the condition of the ground in which the steel pipe pile 1 is buried, the outer diameter d of the steel pipe 2, the number of steel plates 10a to 10c, and 20a to 20c. 1.5 to 2.
Five times moderate is desirable.

In this case, as the lower wing 10 is farther away from the tip of the steel pipe 2, the turbulence of the ground below the tip of the steel pipe pile 1 is reduced, so that the ground supporting force is increased. Since the guidance function does not work, the penetration force decreases, and the ground support force also decreases. For this reason, it is preferable that the lower blade 10 be provided in a region from the lower end of the steel pipe 2 to a height (0 to 1.0 d) corresponding to the outer diameter d of the steel pipe 2.

Also, the inclination angle (pitch) of the lower blade 10 and the upper blade 20, in other words, the steel plate 10 a (or 20 a)
The height h from the lowest position of the mounting portion of the steel plate 10c (or 20c) to the steel tube 2 from the lowest position of the mounting portion to the steel tube 2 is:
Although it depends on the condition of the ground in which the steel pipe pile 1 is buried, the outer diameter d of the steel pipe 2, the number of steel plates 10a to 10c, 20a to 20c, etc., generally h = 0.1 to 0.8d (where d is The outer diameter of the steel pipe 2) may be sufficient. If necessary,
For example, a disc-shaped steel bottom plate may be attached to the tip of the steel pipe 2 by welding to close the tip opening.

The steel pipe pile 1 constructed as above is shown in FIG.
As shown in FIG. 2, the auger 31 is mounted on a base machine 30 as a construction device, is rotated by the auger 31, is screwed into the ground by the screw action of the lower wing 10 and the upper wing 20, and is buried.

Embodiment 2 FIG. 4 is a perspective view of Embodiment 2 of the present invention, and the same or corresponding parts as those in Embodiment 1 are denoted by the same reference numerals. In the present embodiment, the steel plates 10d and 10e made of fan-shaped flat plates obtained by dividing a donut-shaped steel plate into two equal parts as shown in FIG. The lower wing 10 is formed by welding at the same height at the same height and in the same direction at the same angle to form a lower wing 10.
The upper stage blade 20 is provided in the vicinity of the middle part in the longitudinal direction. The construction method and operation and effect of the present embodiment are the same as those of the first embodiment, but the steel plates 10d, 10e, 20d, and 20e of the lower wing 10 and the upper wing 20 are staggered from each other. This has the effect of excavating the ground below the tip of the steel pipe pile 1.

Embodiment 3 FIG. 5 is a perspective view of Embodiment 3 of the present invention, and FIG.
In the cross-sectional view, the same or corresponding portions as those of the first embodiment are denoted by the same reference numerals. In the present embodiment, the steel pipe 2
As shown in FIG. 7, a mounting portion 3 cut off in a spiral shape is provided at a tip end of the mounting portion 3, and a step portion 3 forming the mounting portion 3 is provided.
The height h (and therefore the pitch) of a is the state of the ground in which the steel pipe pile 1 is buried, the outer diameter d of the steel pipe 2, and the steel plates 10f to 10h.
, Etc., but generally h = 0.2-0.
It is desirable to be about 8d (d is the outer diameter of the steel pipe).

The steel plates 10f, 10 constituting the lower wing 10
g and 10h are formed by dividing a circular steel plate having an outer diameter D ₁ (for example, D ₁ = 2d) larger than the outer diameter d of the steel pipe 2 into three equal parts, and forming them as substantially fan-shaped flat plates. The steel plates 10f to 10h are joined to the mounting portion 3 of the steel pipe 2 by welding so that the pointed end thereof is aligned with the center of the steel pipe 2, thereby forming the spiral lower stage blade 10.

As in the case of the first embodiment, the upper blade 20 is formed by joining fan-shaped steel plates 20a to 20c to the outer peripheral surface of the steel pipe pile 1 in the vicinity of an intermediate portion in the longitudinal direction by welding. The construction method and operation and effect of this embodiment are described in Embodiment 1.
However, since most of the opening at the tip of the steel pipe pile 1 is closed by the steel plates 10f to 10h, almost no earth and sand enter the steel pipe pile 1 during construction.

Fourth Embodiment FIG. 8 is a perspective view of a fourth embodiment of the present invention, and FIG.
In the cross-sectional view, the same or corresponding portions as those in Embodiment 2 (FIG. 4) are denoted by the same reference numerals. In the present embodiment, the distal end of the steel pipe 2 is divided into two equal parts in the circumferential direction as shown in FIG. 10 (in FIG. 10, the steel pipe 2 is turned upside down for ease of explanation). Then, it is divided into two by the steps 3a and 3b, and the lower end of the step 3a and the upper end of the step 3b, and the lower end of the step 3b and the upper end of the step 3a are continuous with the inclined surfaces 4a and 4b, respectively. In this way, a letter-shaped mounting portion facing in the same direction is formed. In addition, the slope 4
The height h of the steps 3a, 3b forming the a, 4b differs depending on the condition of the ground in which the steel pipe pile 1 is embedded, the outer diameter d of the steel pipe 2, the number of steel plates, and the like. 2-0.8d
(D is the outer diameter of the steel pipe 2).

Steel plates 10i, 10 constituting lower wing 10
j is an outer diameter larger than the outer diameter d of the steel pipe 2 (for example, D ₁ =
The circular steel plate of 2d) is divided into two equal parts and formed into a flat semicircular shape. Such a steel plate 10i, 10j is formed by welding a straight pipe to the center of the steel pipe 2 by welding. 2 and joined to the lower-shaped blades 10a and 5b.
Is configured. The upper wing 20 is constructed by joining fan-shaped steel plates 20d and 20e to the outer peripheral surface near the longitudinal middle portion of the steel pipe pile 1 by welding, as in the case of the second embodiment. The construction method and operation and effect of this embodiment are the same as those of the third embodiment.
Is the same as

Fifth Embodiment FIG. 11 is a perspective view of a fifth embodiment of the present invention.
The same or corresponding parts as in FIG. 5 are denoted by the same reference numerals. In this embodiment, the spirally formed upper wing 20
The pitch P _2, greater than the pitch P ₁ of the lower wing 10,
Which was formed on the P _2> P _1, generally, the pitch P ₂ of the upper blade 20, it is preferable to 1.5-2 times the pitch P ₁ of the lower blade 10. With this configuration, the pushing force into the ground increases, and the penetration pitch of the steel pipe pile 1 increases. This embodiment can also be applied between the lower wing 10 and the upper wing 20 of Embodiments 1 to 4 and Embodiment 6 described later.

Sixth Embodiment FIG. 12 is a perspective view of a sixth embodiment of the present invention, and the same or corresponding portions as those in the fifth embodiment are denoted by the same reference numerals.
In the present embodiment, the outer diameter D ₄ of the upper wing 20 is larger than the outer diameter D ₃ of the lower wing 10 such that D ₄ > D _{3. In} general, the outer diameter D ₄ of the upper wing 20 is it is preferable to 1.2 to 1.5 times the outer diameter D ₃ of 10. With this configuration, when the steel pipe pile 1 is constructed, the upper stage wings 20 bite and rotate outside the ground disturbed by the lower stage wings 10, so that a downward pushing force is increased and a penetration pitch can be increased. .

In the steel pipe pile 1 according to Embodiments 1 to 6 configured as described above, since the lower wing 10 and the upper wing 20 protrude greatly from the outer peripheral surface of the steel pipe 2, when screwed into the ground, The lower wing 10 has a function of cutting into the ground below and screwing the steel pipe pile 1 and a function of guiding earth and sand below the steel pipe pile 1 to the side of the steel pipe 2 and compressing the same. Reference numeral 20 has a function of pushing the steel pipe pile 1 downward.

Further, after the construction, when functioning as a pile for supporting a vertical load by an overlying building or the like, a portion protruding from the outer periphery of the steel pipe 2 of the lower wing 10 (Embodiments 3 and 4)
In this case, the entire area of the steel plate piles 10f to 10j of the lower stage blade 10 (including the portion where the tip opening of the steel pipe pile 1 is closed) functions as a support, and further, the upper stage blade 20 projecting from the outer peripheral surface of the steel tube 2 However, the ground support force can be obtained to some extent.

In general, since the steel pipe pile 1 is as long as about 10 m to 40 m, a plurality of steel pipes 2 having a length of about 10 m are joined on site to form the steel pipe pile 1 having a predetermined length. In the present invention, the lower wing 10 is attached to a lower pile (a state-of-the-art steel pipe 2), and the upper wing 20
Is attached to, for example, a middle pile or an upper pile. Then, as shown in FIG. 18, when the lower end portion of the steel pipe pile 1 reaches the support layer, the ground support force can be further increased if the upper stage wing 20 is located in a relatively solid formation.

Embodiment 7 By the way, when the outer diameter of the steel pipe 2 increases, the outer diameter of the lower blade 10 also increases as described above.
The thickness of the steel plates 10a to 10h also increases. As a result,
For example, when the steel pipe pile 1 is screwed into the ground by the base machine 30 as shown in FIG. 17, a large resistance due to the ground is applied to the end of the lower wing 10 on the rotation direction side, and if the torque is weak, rotation becomes impossible. You may not be able to penetrate the ground. For this reason, there arises a problem that the base machine 30 must be increased in size. In the present embodiment, in order to solve such a problem, as shown in FIG. 13 and FIG.
0 steel plates 10d and 10e are cut into sharp edges (ends on the rotation direction side) at an acute angle to provide an inclined surface 11, thereby reducing the resistance of the ground applied to the ends and making it easier to penetrate into the ground. Thus, the torque is reduced. In the example of FIG. 15, the excavation blade 12 for assisting the excavation of the lower wing 10 is attached to the bite portion of the steel plates 10d and 10e.

Eighth Embodiment FIG. 16 shows an eighth embodiment of the present invention.
When the steel plate 1 is screwed into the ground and buried,
In order to prevent the ends of 0d and 10e from being deformed, a reinforcing steel plate 14 is attached to the cut-in portions of the steel plates 10d and 10e. Embodiments 7 and 8 may be applied to the steel plates 20 a to 20 e of the upper wing 20, or may be applied to the lower wing 10 or the lower wing 10 and the upper wing 20 of Embodiments 1 to 6.

[0032]

FIG. 17 shows a steel pipe pile 1 according to Embodiment 1 of the present invention.
It shows an example of construction test when burying underground
The outer diameter of the steel pipe 2 constituting the steel pipe pile 1 is 500 m.
m, wall thickness: 14 mm, length: 34 m, and the steel plates 10 a to 10 c of the lower wing 10 have an outer diameter of 1000 mm.
Thickness: A 40 mm donut-shaped steel plate is divided into three parts to form a steel pipe 2
Is mounted 50 mm above the tip of the upper wing 20, and the steel plates 20a to 20c of the upper wing 20 have an outer diameter of 1300 mm and a thickness of 25 mm.
Was divided into three parts and attached 18 m above the lower end of the lower wing 10. The lower wing 10 and the upper wing 20 were attached to the steel pipe 2 by welding. The torque of the steel pipe pile 1 was transmitted to the pile head by the auger 31 mounted on the base machine 30. Fig. 1
As shown in Fig. 8, the soft stratum extends from the surface to a depth of 11m,
The next 6 m depth is the intermediate sand layer, the next 14 m depth is the soft formation, and the further depth is the support layer (very hard formation). As a result of this construction test, the steel pipe pile 1 can be buried to a predetermined depth smoothly in a short time, and the lower wing 10 is
The upper wing could be located in the middle sand layer.

As described above, when the steel pipe pile according to the present invention is buried in the ground by screwing by applying a rotational force to the steel pipe pile 1, the lower wing 10 and the upper wing 20 are surrounded by the same as the action of the screw. It has a function of propelling the steel pipe pile 1 downward by the reaction force from the ground.

Further, the steel pipe pile 1 according to the present invention has a lower wing 1
A large ground support capacity can be obtained with a total area of 0,
Further, the ground support force of the upper wing 20 can be obtained. Further, the earth and sand located below the steel pipe pile 1 is extruded to the side by the lower wing 10 and compressed, resulting in high density earth and sand. In addition to the supporting force of the lower wing 10, a large supporting force due to circumferential friction is obtained. Can be In the description of Embodiments 1 to 8, two of the lower wing 10 and the upper wing 20 are made of three steel plates 10a to 10a.
Although the case where the lower and upper wings 10 and 20a to 20e are configured is shown, the number of steel plates constituting the lower wing 10 and the upper wing 20 may be two or more, and preferably about two to four.

Also, the case where the lower wing 10 and the upper wing 20 are made of the same type of steel plate is shown. For example, in the steel pipe pile 1 of the first embodiment (FIG. 1), the lower wing 10 is made of steel plate. 10a to 10c, and the upper wing 20 is made of the steel plates 20d and 20e of the second embodiment (FIG. 4).
0 and the upper wing 20 may be made of different types of steel plates. In addition, the steel plates 10a to 10c of the lower wing 10 and the upper wing 20
Although the case where the sum of the inner angles of 10j and 20a to 20e is 360 ° has been described, the present invention is not limited to this, and may be about 330 ° to 390 ° for practical use.

According to the present invention, the steel pipe pile 1 can be screwed into a solid stratum for the following reasons. (1) Since the force for pushing the steel pipe pile 1 downward by the upper wing 20 is strong, even if the lower wing 10 enters the hard stratum, the rotation is prevented or reduced. (2) The lower blade 10 not only cuts into the side of the steel pipe 2 but also excavates to the ground below the steel pipe pile 1 and pushes the same to the side. (3) The lower wing 10 and the upper wing 20 are divided into a plurality of parts, and a portion that digs into the ground below the steel pipe pile 1 can be secured by the number of divisions, so that the digging force is increased.

[0037]

【The invention's effect】

(1) The screw-in type steel pipe pile according to the present invention is a fan-shaped steel plate obtained by dividing a wing attached to a steel pipe into a plurality of donut-shaped steel plates having an outer diameter larger than the outer diameter of the steel pipe in the vicinity of the tip of the steel pipe pile. A lower wing attached in a spiral shape to the outer peripheral surface of the same or at the same height position on the outer peripheral surface near the tip of the steel pipe pile in the same direction and inclined at the same angle, according to the steel plate of this lower wing A steel plate with a structure is spirally attached to the outer peripheral surface near the middle part in the longitudinal direction of the steel pipe pile in the same direction as the lower wing, or at the same height position on the outer peripheral surface near the middle part in the longitudinal direction of the steel pipe pile. Since it is constituted by the wings and the upper wings attached in the same direction and at the same angle, the following effects can be obtained.

Since the steel plates constituting the lower and upper wings are flat, they do not need to be bent, so that they can be manufactured at low cost, and furthermore, dimensional errors in manufacturing hardly occur. Since the lower wing and upper wing are made of divided steel plates, it is easy to set the steel plates on the steel pipe, and even if there is some dimensional accuracy error, the gap between the steel pipe and the steel plate can be adjusted. Therefore, welding is easy. Since the upper wing for pushing the steel pipe pile downward is provided in the vicinity of the middle part in the longitudinal direction of the steel pipe pile, the penetration pitch of the steel pipe pile can be made close to the pitch of the lower wing.

(2) Further, in the screw-in type steel pipe pile according to the present invention, the tip portion is cut off spirally to form an attachment portion, or the tip portion is divided into a plurality of pieces in the circumferential direction, and the divided individual pieces are divided. A lower wing in which a steel pipe in which a ridge-shaped mounting portion is formed in the same direction in the same direction, and a steel plate in which a circular steel plate having an outer diameter larger than the outer diameter of the steel pipe is divided into a plurality of pieces is mounted on the mounting portion of the steel pipe. When,
A fan-shaped steel plate obtained by dividing a donut-shaped steel plate whose outer diameter is larger than the outer diameter of the steel pipe into a plurality of pieces is spirally wound on the outer peripheral surface near the middle part in the longitudinal direction of the steel pipe pile in the same direction as the steel plate of the lower wing. Mounting,
Alternatively, since the lower wing is provided at the same height position on the outer peripheral surface in the vicinity of the longitudinal middle portion of the steel pipe pile, and the upper wing is attached in the same direction and at the same angle, almost the same effect as the above (1) is obtained. Can be obtained.

(3) The pitch per rotation of the upper wing of the screw-in type steel pipe pile of (1) or (2) is set to one pitch of the lower wing.
Since the pitch is larger than the pitch per rotation, the pushing force of the steel pipe pile downward is increased, and the penetration pitch can be increased.

(4) Since the outer diameter of the upper wing of the screwed steel pipe pile of the above (1), (2) or (3) is made larger than the outer diameter of the lower wing, the outer diameter of the ground disturbed by the lower wing may be increased. Since the upper wing penetrates, the downward pushing force is increased, and the penetration pitch of the steel pipe piles can be increased.

[Brief description of the drawings]

FIG. 1 is a perspective view of Embodiment 1 of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an explanatory view of the steel plate of FIG. 1;

FIG. 4 is a perspective view of a second embodiment of the present invention.

FIG. 5 is a perspective view of a third embodiment of the present invention.

FIG. 6 is a sectional view taken along line BB of FIG. 5;

FIG. 7 is a perspective view of a tip portion of the steel pipe of FIG. 5;

FIG. 8 is a perspective view of Embodiment 4 of the present invention.

FIG. 9 is a sectional view taken along the line CC in FIG. 8;

FIG. 10 is a perspective view of a tip portion of the steel pipe of FIG. 8;

FIG. 11 is a perspective view of a fifth embodiment of the present invention.

FIG. 12 is a perspective view of Embodiment 6 of the present invention.

FIG. 13 is a perspective view of a main part of a seventh embodiment of the present invention.

FIG. 14 is a side view of a main part of FIG.

FIG. 15 is a perspective view of a main part of another example of the seventh embodiment.

FIG. 16 is a perspective view of a main part according to an eighth embodiment of the present invention.

FIG. 17 is an explanatory view showing a construction example of a screw-in type steel pipe pile according to the present invention.

FIG. 18 is an explanatory view showing a construction example of a screw-in type steel pipe pile according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Screw-in type steel pipe pile (steel pipe pile) 2 Steel pipe 3 Attachment part 10 Lower wing 10a-10h Steel plate 20 Upper wing 20a-20e Steel plate

Continuation of front page (72) Inventor Masahiro Hayashi 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd.

Claims (4)

[Claims] 1. A screw-in type steel pipe pile embedded in the ground by screwing using a blade attached to a steel pipe, wherein the blade is divided into a plurality of donut-shaped steel plates having an outer diameter larger than the outer diameter of the steel pipe. A lower stage in which a steel plate of a shape is spirally attached to the outer peripheral surface near the tip of the steel pipe pile, or is attached at the same height and at the same angle at the same height position on the outer peripheral surface near the tip of the steel pipe pile. A wing, and a steel plate having a structure similar to that of the steel plate of the lower wing is spirally attached to the outer peripheral surface near an intermediate portion in the longitudinal direction of the steel pipe pile in the same direction as the lower wing, or A screw-in type steel pipe pile comprising the lower wing and the upper wing inclined at the same direction and at the same angle at the same height position on the outer peripheral surface in the vicinity of the middle part in the direction. 2. A screw-in type steel pipe pile embedded in the ground by screwing using a wing attached to a steel pipe, wherein a tip portion is cut off spirally to form an attachment portion, or a tip portion is formed in a circumferential direction. A steel pipe which is divided into a plurality of parts and each of the divided parts is formed with a letter-shaped mounting portion in the same direction in the same direction, and a steel plate obtained by dividing a circular steel sheet having an outer diameter larger than the outer diameter of the steel pipe into a plurality of pieces. And a fan blade-shaped steel plate obtained by dividing a donut-shaped steel plate having an outer diameter larger than the outer diameter of the steel pipe into a plurality of pieces, and an outer periphery near an intermediate portion in a longitudinal direction of the steel pipe pile. Surface in the same direction as the steel plate of the lower blade, spirally attached in the same direction, or in the same direction as the lower blade at the same height position on the outer peripheral surface near the middle part in the longitudinal direction of the steel pipe pile, inclined at the same angle A screw-in type steel pipe pile comprising an upper wing attached thereto. 3. The screw-in type steel pipe pile according to claim 1, wherein a pitch per rotation of the upper blade is formed larger than a pitch per rotation of the lower blade. 4. The screw-in type steel pipe pile according to claim 1, wherein the outer diameter of the upper wing is larger than the outer diameter of the lower wing.