JPH1136287A - Screw type steel pipe pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw type steel pipe pile which enables the easy manufacture of a steel vane at a low cost, can reduce the labor and cost for fitting the steel vane to a steel pipe, enables the smooth work execution on various ground soil properties, has large vertical bearing power, can cope with the bending moment transferred to a steel pipe from the steel vane, and can cope with the economy. SOLUTION: Flat steel sheets 10a, 10b split with a doughnut-like steel sheet having the outer diameter 1.5-2.5 times the outer diameter of a steel pipe 2 and the inner diameter nearly equal to the inner diameter of the steel pipe 2 into multiple parts are fitted to the outer periphery near the tip section of the steel pipe 2 at nearly the same angle to be connected together to form a vane 10 fitted to the steel pipe 2 into a nearly spiral shape. The steel vane 10 is constituted of the steel sheets 10a, 10b so that the sum of the internal angles is set to the range of 315 deg.-540 deg..

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 screw-in type steel pipe pile in which steel wings are mounted on at least an outer peripheral surface near a tip portion of a steel pipe.

[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 such a conventional screw-in type 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).

[0004] 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 half-turn length and an outer diameter of about 1.5 to 3 times the pile main body, is made of steel pipe. A plurality of piles are fixed discontinuously relative to each other with the same helix direction at the same height position on the outer peripheral surface of the lower end of the pile (prior art 2).

[0005]

The above prior art 1 has the following problems. (1) Manufacturing problems (a) It takes a lot of labor and cost to manufacture a spiral wing by bending a flat plate. In order to manufacture a spiral wing, one part of a donut-shaped flat plate is cut and bent into a spiral shape, but it is not easy to bend the entire surface at a uniform angle. In particular, when the outer diameter of the steel pipe is increased to about 500 mm, the spiral blade needs to have a thickness of about 40 mm, and the processing equipment becomes large.

(B) It takes time to insert a steel pipe into the spiral blade. When a spiral wing is manufactured by bending a donut-shaped flat plate, a dimensional error occurs in the inner diameter of the spiral wing, and a portion having a diameter smaller than the outer diameter of the steel pipe is likely to be generated. Also, welded steel pipes such as spiral steel pipes and UOE steel pipes generally used as steel pipe piles are more difficult to insert because the weld bead at the seam is raised.

(C) The welding work of the spiral blade and the steel pipe requires a lot of labor and cost. When manufacturing the steel pipe, it does not become a perfect circle, but rather an ellipse.Because of the aforementioned dimensional error of the inner diameter of the spiral blade, the inner edge of the spiral blade and the outer circumference of the steel pipe do not contact uniformly, and there is a partial gap. Therefore, it takes time for the welding operation, and welding defects are easily generated.

(2) Problems in screwing work (a) When a steel pipe pile is screwed and buried in the ground containing large cobblestones, since the spiral blades are almost one turn, cobblestones are formed between the terminal points of the spiral blades. It becomes clogged and cannot be penetrated by subsequent screwing. It is conceivable to increase the gap width at the end and start points by making the slope of the spiral extremely large. However, if the slope is too large, the penetration resistance will increase, resulting in a large-sized construction machine and an uneconomical construction method.

(B) When the tip of a steel pipe pile suddenly enters a hard stratum from a soft stratum, since the spiral wing is almost one turn, there is insufficient propulsive force to push the steel pipe pile downward, and the steel pipe pile cannot penetrate. May be. The longer the helix, the greater the propulsion. (C) Since the lower end of the steel pipe pile is completely closed using the bottom plate, if it hits a very hard ground, it will idle and cannot penetrate thereafter.

(3) Problems in Mechanics When a vertical force acts on a steel pipe pile after completion of the above-mentioned structure,
The spiral blade receives an upward reaction force from the ground below, and a large bending moment is generated in the spiral blade. This bending moment is transmitted to the steel pipe, and generates bending stress in the steel pipe around the helical blade mounting portion. When the outer diameter of the steel pipe is as small as about 200 mm, which has been used for many years, this bending stress is not so large. However, when the outer diameter of the steel pipe is as large as about 500 mm, a serious problem occurs. The wall thickness of a general steel pipe pile having an outer diameter of 500 mm is usually about 10 mm, but according to FEM analysis performed by the inventors, 20 mm near the spiral blade attachment portion.
It is necessary to have a certain thickness, and it is very uneconomical to increase the total length of the steel pipe pile in this way.

(4) Problems in Supporting Force When the ground is soft, the amount of penetration per rotation of the steel pipe pile is almost equal to the pitch determined by the dimensional shape of the spiral wing. However, in practice, the amount of penetration per rotation must be smaller than the pitch of the spiral blade. At this time, the spiral wing is a phenomenon closer to the expression of scraping the ground at the lower end of the spiral wing, rather than cutting into the ground. For this reason, it disturbs the ground around the spiral wing,
The vertical bearing capacity is reduced to a different extent depending on the ground.

Further, the prior art 2 is based on (1)-(a), (1)-(c), (2)-(a),
It has the same problems as (2)-(b), (3) and (4), but (2)-(b) is a major problem. That is, unlike the spiral wing that makes one round of the steel pipe, the conventional technique 2 has a greater ability to scrape the ground, but the length of one wing is as short as half the circumference of the steel pipe, and soil and sand are easily moved. The propulsion force to push in tends to be insufficient, and it is easy to cause idling.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is easy to manufacture steel wings at a low cost.
The effort and cost of installing steel wings on steel pipes can be reduced. It can be applied smoothly to various soil types,
In addition, the vertical support is large. It is another object of the present invention to provide a screw-in type steel pipe pile which can not only cope with a bending moment transmitted from a steel wing to a steel pipe but also can cope economically.

[0014]

SUMMARY OF THE INVENTION The present invention relates to a screw-in type steel pipe pile embedded in the ground by screwing using a wing attached to a steel pipe and having the following construction. (1) The blade attached to the steel pipe is made of a flat steel plate obtained by dividing a donut-shaped steel plate having an outer diameter of 1.5 to 2.5 times the outer diameter of the steel pipe and having an inner diameter substantially equal to the inner diameter of the steel pipe. The plate is attached to the outer peripheral surface near the distal end of the steel pipe so as to be continuous with each other at substantially the same angle, and is formed in a substantially spiral shape. It is composed of steel wings.

(2) In the screw-in type steel pipe pile according to the above (1), whether the outer diameter of the steel pipe is substantially equal to that of the steel wing on the outer peripheral surface of the steel pipe above the steel wing. Alternatively, a second steel wing is provided which is larger and mounted in the same direction as the steel wing.

(3) In the screwed steel pipe pile of the above (1) or (2), the steel wing or the portion where the steel wing and the second steel wing are mounted is thicker than the wall thickness of the upper steel pipe. It is constructed of a thickened steel pipe or a strengthened steel pipe having a higher material strength than the steel pipe.

(4) In the screw-in type steel pipe pile according to any one of the above (1) to (3), the steel pipe or the reinforcing steel pipe is formed on the inside of the steel pipe or the reinforcing steel pipe at or near the tip thereof. A disk-shaped or donut-shaped steel bottom plate having an outer diameter substantially equal to the diameter or the inner diameter is attached.

(5) In the screw-in type steel pipe pile according to any one of the above (1) to (4), immediately before or after the driving of the steel pipe pile driving, the steel pipe pile is brought into the ground from or near the tip thereof. A solidified material is injected into the steel pipe pile to form an integral part.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. 1 is a perspective view of a screw-in type steel pipe pile according to Embodiment 1 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 steel blade attached to the outer peripheral surface of the steel pipe 2 in the vicinity of the distal end of the steel pipe 2, that is, slightly above the outer peripheral surface of the distal end of the steel pipe 2 or the distal end.

As shown in FIG. 3, the outer diameter D ₁ of the steel wing 10 is larger than the outer diameter d of the steel pipe 2 (for example, D ₁ = 2).
d), the inner diameter D ₂ is composed of approximately equal toroidal steel bisecting the flat plate and the outer diameter d of the steel pipe 2 the steel plate 10a, 10
b is 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 in a substantially spiral manner so as to be continuous with each other at substantially the same angle. The size of the steel wing 10 depends on the condition of the ground in which the steel pipe pile 1 is buried,
Although it differs depending on the outer diameter d of the steel pipe 2 and the number of the steel plates 10a and 10b, it is generally preferable that the outer diameter d of the steel pipe 2 is 1.5 to 2.5 times appropriate. Is approximately 360 °.

In this case, as the steel 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 direction guidance function does not work, the penetration force is reduced and the ground support force is also reduced. According to the results of various studies conducted by the inventors, the steel wing 10 is connected to the steel pipe 2 from the lower end of the steel pipe 2.
It is desirable to provide it in a region up to a height (0 to 1.0d) corresponding to the outer diameter d of.

Further, the inclination angle (pitch) of the steel wing 10,
In other words, the height h from the lowest position of the mounting portion of the steel plate 10a to the steel pipe 2 to the highest position of the mounting portion of the steel plate 10b to the steel pipe 2 is the state of the ground in which the steel pipe pile 1 is buried, It depends on the outer diameter d of the steel pipe 2, the number of steel plates 10a and 10b, etc.
Generally, it is sufficient that h is about 0.1 to 0.5d (where d is the outer diameter of the steel pipe 2).

FIG. 4 shows another example of the present embodiment.
In this example, above the steel pipe blade 10 of the steel pipe 2 of FIG.
A second steel wing (hereinafter referred to as an upper wing) 20 including steel plates 20a and 20b having the same structure as the steel plates 10a and 10b constituting the steel wing 10 is provided. In this case, the interval H between the steel blade 10 and the upper blade 20 is determined by the state of the ground to be buried, the outer diameter d of the steel pipe 2, the steel plates 10a, 10b, 20a, and
In general, H = 1.0 to
5.0 d (where d is the outer diameter of the steel pipe 2) is desirable,
Depending on the ground conditions, the steel pipe pile 1 may be provided in the vicinity of an intermediate portion in the longitudinal direction.

The steel pipe pile 1 constructed as above is shown in FIG.
As shown in (1), it is attached to an auger 31 mounted on a base machine 30 which is a construction device, is rotated by the auger 31, is screwed into the ground by the screw action of the steel wing 10, and is buried.

The steel pipe pile 1 according to this embodiment has a steel wing 10
Since the upper wing 20 (and the upper wing 20) protrudes greatly from the outer peripheral surface of the steel pipe 2, the steel wing 10 (and the upper wing 20) bites into the ground and is screwed into the ground during the screwing work into the ground.
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. Also,
After construction, when functioning as a pile for supporting a vertical load by an overlying structure or the like, the entire area of the portion of the steel wing 10 protruding from the outer periphery of the steel tube 2 functions as a support, and furthermore, the outer periphery of the steel tube 2 The upper wing 20 protruding from the surface can also obtain the ground support force to some extent.

Embodiment 2 FIG. 5 is a perspective view of Embodiment 2 of the present invention, and FIG. 6 is a longitudinal sectional view thereof. Note that the same parts as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, a reinforcing steel pipe 5 made of a steel pipe having a thickness greater than the thickness of the steel pipe 2 is welded to a tip end of the steel pipe 2 constituting the steel pipe pile 1, and steel plates 210 a and 10 b are attached to the outer peripheral surface of the reinforcing steel pipe 5. Steel wing 1
0 is attached. In this case, the steel wing 10 may be attached after joining the strengthened steel pipe 5 to the steel pipe 2, or the strengthened steel pipe 5 to which the steel wing 10 is attached may be joined to the steel pipe 2.

FIG. 7 shows another example of this embodiment.
A long reinforcing steel pipe 5 is joined to the tip of the steel pipe 2, and a steel wing 10 and an upper wing 20 are attached to the reinforcing steel pipe 5.
In the present embodiment, a strengthened steel pipe having a higher strength than the steel pipe 2 may be used instead of the thickened steel pipe 5 having a large thickness. The steel pipe pile according to the present embodiment configured as described above,
It is buried in the ground as in the case of the first embodiment.

Incidentally, in order to receive a large ground reaction force by the steel blade 10, the steel blade 10 is required to have high rigidity. For example, the outer diameter of the steel pipe 2 is 500 mm, and the steel wing 10
When the outer diameter of the steel wing is 1000 mm, a large bending moment is generated in the steel wing 10 due to the ground reaction force. Therefore, it is required to use a steel plate having a thickness of about 40 mm in design,
This bending moment is transmitted to the steel pipe 2 to generate a large bending stress as shown in FIG.

In the present embodiment, by using a strengthened steel pipe 5 having a thickness greater than the thickness of the steel pipe 2 or a strengthened steel pipe having a strength greater than that of the steel pipe 2 for a portion of the steel pipe pile 1 which is affected by bending stress. Since the generated stress can be kept within the allowable stress in the portion affected by the bending stress, no large bending stress occurs in the steel pipe 2.

The thickness of the reinforcing steel pipe 5 and its height H ₁ are determined by numerical analysis in consideration of the assumed ground reaction force. For example, when the diameter of the steel pipe 2 is 500 mm, the diameter of the steel wing 10 is 1000 mm, and a vertical load of 500 t is applied, in a normal steel pipe, the portion where only the axial force is applied has a thickness of 14 mm and a yield stress (2400 kgf). / C
A steel pipe having a wall thickness of about 20 mm is required in order to contain the stress in the portion where both the axial force and the bending moment act within the range of m ² ) within the allowable stress. Therefore, the method of increasing the thickness of the steel pipe 2 and directly attaching the steel wings 10 to the steel pipe 2 is uneconomical.

Therefore, if a strengthened steel pipe 5 thicker than the steel pipe 2 or a strengthened steel pipe higher in strength than the steel pipe 2 is used in a portion where the bending moment acts, it is not necessary to increase the thickness of the steel pipe 2, so that it is economical. In addition, it is possible to sufficiently cope with the bending moment. In addition, the strengthened steel pipe 5 is
Since it is only joined by welding, various sizes can be used according to the applied load.

Embodiment 3 In each of the above embodiments, a circular steel plate is divided into a plurality of equal parts, and steel wings 10a and 10b having a sum of 360 ° of inner angles are used.
In the present embodiment, the sum of the inner angles of the steel plates 10a and 10b is smaller than 360 °, and
Alternatively, it is formed larger than 360 °. FIG. 9 shows that the sum of the internal angles of the steel plates 10a and 10b is smaller than 360 °, and a gap 11 is formed between the steel plates 10a and 10b as shown in FIG. FIG. 10 shows that the sum of the internal angles of the steel plates 10a, 10b, 10c, and 10d is 360 °.
With a larger size, an overlap 12 occurs between the steel plates 10a and 10d as shown in FIG. The above configuration is the same for the upper wing 20 as well.

According to the results of field tests and numerical analysis performed by the inventors, the steel plates 10a, 10b,.
By setting the sum of the inner angles of the steel blades to 315 ° or more, clogging between the start and end of the steel wing 10 due to the cobblestone can be prevented at the time of construction, and a steel wing of one turn (the sum of the inner angles of the steel plate is 360
°) can be obtained, and by setting the sum of the inner angles to 540 ° or less, sufficient thrust can be obtained even at the boundary where soft ground moves to hard ground. . For this reason, the sum of the inner angles of the steel plates 10a, 10b,.
It is preferable that the angle be in the range of ° to 540 °. The upper wing 2
0 may have the same configuration.

In this case, the steel plate 1 constituting the steel wing 10
It is not necessary to make all the inner angles of 0a, 10b,... Equal, and they may be slightly different. In addition, gap 11 or overlap 1
2 does not need to be concentrated in one place;
a, 10b,... may be provided as appropriate.

Embodiment 4 In this embodiment, a disc-shaped or donut-shaped steel bottom plate 6 or 7 is attached to or near the lower end of the steel pipe pile 1. That is, FIG. 13 (a) shows a disk-shaped steel bottom plate 6 joined to the tip of the steel pipe 2 by welding.
3 (b) is a doughnut-shaped steel bottom plate 7 joined to the tip of the steel pipe 2 by welding. FIG. 13 (c) shows a disk-shaped steel bottom plate 6 joined by welding to the inside near the tip of the steel pipe 2, and FIG. 13 (d) shows a donut-shaped steel bottom plate 7 joined in the same manner. Things. In this case, if the steel bottom plate 6 or 7 is joined to a position corresponding to the steel wing 10, an effect of reinforcing the mounting portion of the steel wing 10 can be obtained.

In the steel pipe pile 1 according to the present embodiment configured as described above, all or a part of the distal end opening is made of steel bottom plates 6 and 7.
Since the steel wing 10 protrudes greatly from the outer peripheral surface of the steel pipe 2 at the time of screwing into the ground,
The steel 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.

Further, after the construction, when functioning as a pile for supporting a vertical load by an overlying structure or the like, the steel pipe 2
Steel bottom plates 6 and 7 for closing all or part of the lower end opening
And the entire area of the steel wing 10 and the portion protruding from the outer periphery of the steel pipe 2 functions as a support.
When 0 is provided, some ground support force can be obtained.

As described above, the steel wing 10 has both a function of projecting to the outer periphery of the steel pipe 2 and cutting into the ground, and a function as a support. It is known that the ground bearing capacity of a steel pipe pile whose tip is closed is proportional to the closed area,
For example, when the lower end opening of the steel pipe 2 is completely closed, if the outer diameter of the steel wing 10 is twice as large as the outer diameter of the steel pipe 2, the area of the steel wing becomes four times as large as that without the steel wing. Very large ground support is obtained. In this embodiment, the steel pipe pile 1 to which the disk-shaped steel bottom plate 6 is attached may be used in a place where the ground is relatively soft, and the steel pipe pile to which the donut-shaped steel bottom plate 7 is attached may be an emergency. If it is used for hard ground, the earth and sand is taken into the steel pipe 2 during the screwing and burying, so that it can easily penetrate.

In each of the above embodiments, except for the case of FIG. 10, the case where the steel wing 10 and the upper stage wing 20 are respectively constituted by two steel plates 10a, 10b, 20a and 20b is shown. The steel plates constituting the wing 10 and the upper wing 20 are 2
Any number of sheets may be used, and preferably about 2 to 4 sheets.

Although the steel blade 10 and the upper blade 20 have the same outer diameter, both may have different outer diameters. In this case, it is desirable that the outer diameter of the upper wing 20 be larger than the outer diameter of the lower wing 10. With this configuration, the upper wing 20 is disposed outside the ground disturbed by the steel wing 10 when the steel pipe pile 1 is constructed. Since the wings 20 bite and rotate, the downward pushing force increases, and the penetration pitch 2
Since 0 is bitten and rotated, the pushing force downward is increased, and the penetration pitch can be increased.

Embodiment 5 FIG. 14 is an explanatory diagram of this embodiment. In the present embodiment, when the steel pipe pile 1 is driven into the ground, the solidification material injection pipe 13 is inserted into the steel pipe pile 1 immediately before or after hitting, and the tip of the steel pipe pile 2 or the steel wing 10 From the vicinity, the lower part of the steel pipe 2 (or the reinforcing steel pipe 5) in the ground and around the steel wing 10,
For example, a solidifying material 14 such as cement milk, cement mortar, or liquid resin is injected and integrated with the steel pipe pile 1. Thereby, the ground disturbed by the steel wings 10 when the steel pipe pile 1 is buried is strengthened, and a large supporting force can be obtained.

[0042]

EXAMPLE Next, an example of the present invention will be described with reference to FIG. 15 taking the steel pipe pile 1 of Embodiment 2 shown in FIG. 7 as an example. The steel pipe 2 constituting the steel pipe pile 1 has a length of 25 m and an outer diameter of 500 m.
m, wall thickness 9 mm, material is 40 kg steel. The strengthened steel pipe 5 had a length of 1200 mm, an outer diameter of 500 mm, a wall thickness of 20 mm, and was made of 50 kg steel. The outer diameter of the steel wing 10 is 800 mm, the thickness is 40 mm, and the upper wing 20
Has an outer diameter of 1000 mm and a thickness of 40 mm, each of which is 2 mm.
The steel plates 10a, 10b, 20a, and 20b were formed, and the sum of their internal angles was 315 °. The interval between the steel wing 10 and the upper wing 20 was 750 mm.

Also, the ground at the test site is at a depth of 2 from the surface of the ground.
Average N value of 5 including up to 20 cm of boulders up to 3 m
The clay soil layer having a depth of 23 m or less was a gravel layer having an N value of 50 or more. Then, when the rotation is transmitted to the pile head of the steel pipe pile 1 by the auger 31 mounted on the base machine 30 shown in FIG. 19 and construction is performed, the steel pipe pile 1 can be buried in the ground smoothly and in a short time. Was. As described in the fourth embodiment, even when the steel bottom plate 6 or 7 is attached to the tip of the steel pipe pile 1 or in the vicinity thereof, it was possible to bury the soil without discharging the soil to the surface at all.

In this embodiment, the steel wings 10 and the steel plates 10a, 10b, 20a, 20
Since the sum of the inner angles of b was 315 °, it was possible to prevent the boulders from being clogged between the steel blade 10 and the upper and lower blades 20 at the beginning and end. As described above, the test place was not provided with a hard support layer, but the propulsion force was increased by using a two-stage wing, so that the test piece could penetrate without any trouble.

Embodiment 6 By the way, when the outer diameter of the steel pipe 2 is increased, the outer diameter of the steel blade 10 is also increased as described above.
0, the thickness of the steel plates 10a and 10b also increases.
As a result, for example, as shown in FIG.
When the steel pipe pile 1 is screwed into the ground at 0, a large resistance due to the ground is applied to the end of the steel wing 10 on the rotation direction side. If the torque is weak, the steel wing 10 cannot rotate and cannot penetrate the ground. For this reason, there arises a problem that the base machine 30 must be increased in size. In the present embodiment, as shown in FIG.
The cut-out portion (end in the rotation direction) of the steel plate 10a of No. 0 is cut at an acute angle to provide an inclined surface 15, thereby reducing the resistance of the ground applied to the end portion and making it easier to penetrate into the ground. The torque is reduced. In the example of FIG.
An excavation blade 16 for assisting excavation of the steel wing 10 is attached to a biting portion of the steel plate 10a.

Seventh Embodiment FIG. 18 shows a seventh embodiment of the present invention.
When the steel wing 10 is screwed into the ground and buried,
0a to prevent the end of the steel plate 10a from being deformed.
The reinforcing member 17 is attached to the notched portion.
Embodiments 6 and 7 may be applied to the steel plate 20 a of the upper wing 20.

[0047]

【The invention's effect】

(1) The screw-type steel pipe pile according to the present invention is a donut-shaped wing for screwing into the ground, the outer diameter of which is 1.5 to 2.5 times the outer diameter of the steel pipe and the inner diameter of which is substantially equal to the inner diameter of the steel pipe. A flat steel plate obtained by dividing a steel plate into a plurality of pieces is attached to the outer peripheral surface near the tip of the steel pipe so as to be connected to each other at substantially the same angle to form a substantially spiral shape. 315 ° C-5
The following effects can be obtained because the wings are made of steel wings within a temperature range of 40 ° C.

(A) Since a substantially spiral steel wing is constituted by a flat steel plate, the production of the steel wing is easy and inexpensive, and the labor and cost for attaching to the steel pipe can be reduced. . (B) Since the outer diameter of the steel pipe blade is 1.5 to 2.5 times the outer diameter of the steel pipe, it can be smoothly screwed into the ground at the time of construction, and a large supporting force can be obtained.

(C) By setting the sum of the inner angles of the plurality of steel plates constituting the steel blade to be 315 ° or more, it is possible to prevent the boulder from being clogged between the start and end ends of the steel blade, and furthermore, it is almost one turn. The same propulsive force as a steel pipe pile having spiral wings can be obtained. Further, by setting the sum of the inner angles of the steel plate to 540 ° C. or less, a sufficient propulsion force can be obtained even at a boundary where the ground shifts from soft ground to hard ground. As described above, since the entire length of the steel wing can be changed according to the soil soil, the steel pipe pile can be buried smoothly in various soil soils.

(2) In the screwed steel pipe pile of the above (1), the outer diameter of the steel pipe above the steel wing is substantially equal to or smaller than that of the steel wing in a structure similar to the steel wing. A second steel wing mounted in the same direction as the steel wing
Because of the stepped blade, in addition to the effects (a) to (c),
Greater propulsion and vertical support can be obtained.

(3) In the screw-in type steel pipe pile according to (1) or (2), the steel wing or a portion where the steel wing and the second steel wing are to be mounted is formed so that the wall thickness is larger than the thickness of the steel pipe on the upper side. Since the steel pipe is made of a thick steel pipe or a steel pipe having a higher material strength than the steel pipe, the stress of the steel pipe can be suppressed to an allowable value even when a large bending moment is transmitted from the steel blade.

(4) In the screw-in type steel pipe pile of the above (1), (2) or (3), the steel pipe or the reinforcing steel pipe is provided inside or near the tip of the steel pipe or the reinforcing steel pipe constituting the steel pipe pile. Since a disk-shaped or donut-shaped steel bottom plate having an outer diameter substantially equal to the diameter or the inner diameter is attached, a larger supporting force can be obtained.

(5) In the screw-in type steel pipe pile according to the above (1), (2), (3) or (4), immediately before or after the driving of the steel pipe pile, or near the tip of the steel pipe pile. Since the solidified material is injected into the ground from below, and integrated with the steel pipe pile, a greater supporting force can be obtained.

[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 another example of the first embodiment.

FIG. 5 is a perspective view of Embodiment 2 of the present invention.

FIG. 6 is a longitudinal sectional view of FIG.

FIG. 7 is a perspective view of another example of the second embodiment.

FIG. 8 is a diagram showing a relationship between a distance from a tip of a steel pipe pile and a bending stress generated in a steel pipe due to a bending moment generated in a steel blade.

FIG. 9 is a perspective view of a third embodiment of the present invention.

FIG. 10 is a perspective view of another example of the third embodiment.

FIG. 11 is a bottom view of FIG. 9;

FIG. 12 is a bottom view of FIG. 10;

FIG. 13 is a schematic diagram showing examples of Embodiment 4 of the present invention.

FIG. 14 is an explanatory diagram of Embodiment 5 of the present invention.

FIG. 15 is an explanatory diagram of an embodiment of the present invention.

FIG. 16 is a perspective view of Embodiment 6 of the present invention.

FIG. 17 is a perspective view of another example of Embodiment 6 of the present invention.

FIG. 18 is a perspective view of a seventh embodiment of the present invention.

FIG. 19 is a perspective view showing a construction example of the screw-in type steel pipe pile of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Screw-in type steel pipe pile (steel pipe pile) 2 Steel pipe 5 Reinforced steel pipe 6 Disc-shaped steel bottom plate 7 Donut-shaped steel bottom plate 10 Steel wing 10a-10d Steel plate 14 Solidified material 20 Second steel wing ( Upper stage wing) 20a, 20b steel plate

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Masahiro Hayashi 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd.

Claims (5)

[Claims] 1. A threaded steel pipe pile embedded in the ground by screwing using a wing attached to a steel pipe, wherein the wing has an outer diameter of 1.5 to 2.5 times the outer diameter of the steel pipe and an inner diameter of the wing. A flat steel plate obtained by dividing a donut-shaped steel plate having a diameter substantially equal to the inner diameter of the steel pipe into a plurality of pieces is attached to the outer peripheral surface near the tip of the steel pipe so as to be connected to each other at substantially the same angle, and is formed substantially in a spiral shape. And the sum of the inner angles of the steel plate is 31
A screw-in type steel pipe pile comprising a steel wing having a temperature range of 5 ° C to 540 ° C. 2. An outer peripheral surface of a steel pipe above a steel wing,
A second steel wing having a structure similar to the steel wing and having an outer diameter substantially equal to or larger than the steel wing and mounted in the same direction as the steel wing is provided. Item 7. A screw-in type steel pipe pile according to item 1. 3. A steel wing or a portion where the steel wing and the second steel wing are to be mounted is made of a reinforced steel pipe having a thickness greater than the thickness of a steel pipe above the wing or a reinforced steel pipe having a material strength higher than that of the steel pipe. The screw-in type steel pipe pile according to claim 1 or 2, wherein: 4. A disc-shaped or donut-shaped steel bottom plate having an outer diameter substantially equal to the outer diameter or inner diameter of the steel pipe or the strengthened steel pipe inside or near the tip of the steel pipe or the strengthened steel pipe constituting the steel pipe pile. 2. The device according to claim 1, wherein
4. The screw-in type steel pipe pile according to any one of items 1 to 3. 5. Immediately before or after the driving of the steel pipe pile, a solidified material is injected into the ground from the tip of the steel pipe pile or in the vicinity thereof to be integrated with the steel pipe pile. The screw-in type steel pipe pile according to any one of claims 1 to 4.