JPH1136295A - Screw type steel pipe pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw type steel pipe pile capable of easily manufacturing a steel vane at a low cost, capable of reducing the labor and cost for fitting the steel vane to a steel pipe, allowing smooth execution on the ground containing boulders, having large vertical bearing power, capable of coping with the bending moment transferred to the steel pipe from the steel vane, and capable of being economically coped with. 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 pipe 2 inclinatorily at nearly the same height, at the same angle, and in the same direction to form a vane 10 fitted to the steel pipe 2. The steel vane 10 is constituted of the steel sheets 10a, 10b so that the sum of 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 attached to 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 length of half a circumference and an outer diameter of about 1.5 to 3 times the body of the pile, is made of a steel pipe pile. 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) 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 Structural 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 If the ground is soft, the amount of penetration of the steel pipe pile per rotation is substantially the pitch determined by the dimensional shape of the spiral blade, but in general ground, especially in the support layer. 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 composed of (1)-(a), (1)-(c), (2)-(a),
It has the same problems as (3) and (4), but especially (2)
-(A) is a major problem. That is, in the prior art 1, there is only one place where the cobble may be clogged, but in the prior art 2, since the spiral wing is wound half a turn, there are at least two places where the cobble is clogged, and the steel pipe pile is screwed in. Penetration becomes more difficult.

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. Can be installed smoothly on the ground including cobble stones and has high vertical bearing capacity. 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.

[0013]

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 approximately the same height and the same angle on the outer peripheral surface near the tip of the steel pipe,
The steel wings are mounted so as to be inclined in the same direction, and are constituted by steel blades in which the sum of the inner angles of the steel plate is in the range of 315 ° C to 540 ° C.

(2) In the screw-in type steel pipe pile of the above (1), the portion where the steel wing is to be attached is provided with an enhanced steel pipe having a thickness greater than the thickness of the steel pipe above it or an enhanced steel pipe having a higher material strength than the steel pipe. It consists of.

(3) In the screw-in type steel pipe pile according to the above (1) or (2), the outer diameter or the inner diameter of the steel pipe or the strengthened steel pipe is provided inside or near the tip of the steel pipe or the strengthened steel pipe constituting the steel pipe pile. A disk-shaped or donut-shaped steel bottom plate having an outer diameter substantially equal to that of the steel bottom plate is attached.

(4) In the screw-in type steel pipe pile according to the above (1), (2) or (3), immediately before or after the driving of the steel pipe pile, from the tip of the steel pipe pile or the vicinity thereof to the ground. And a solidified material is injected into the steel pipe pile to form an integral part.

[0017]

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 disposed on the outer peripheral surface of the distal end portion (lower end portion) of the steel pipe 2 or on the outer peripheral surface slightly above the distal end portion with substantially the same height, the same angle, and inclined in the same direction, and joined by welding. is there. The size of the steel wing 10 varies 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 the steel plates 10a, 10b, and the like. ~
2.5 times moderate is desirable, and steel plates 10a, 10b
Are approximately 360 °.

In this case, the further the steel wing 10 is away from the tip of the steel pipe 2, the less the turbulence of the ground below the tip of the steel pipe pile 1, the greater the ground supporting force. 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 (step) from the lowermost part to the uppermost part of the attachment part of the steel plate 10a to the steel pipe 2 depends on the state of the ground in which the steel pipe pile 1 is embedded, the outer diameter d of the steel pipe 2, the steel plate 10a. , 10b, etc., but in general, it may be about 0.1 to 0.5d (where d is the outer diameter of the steel pipe 2).

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
The steel wings 10 protrude greatly from the outer peripheral surface of the steel pipe 2, so that when the steel pipe 10 is screwed into the ground, the steel wing 10 functions to bite into the ground and screw the steel pipe pile 1, and the soil and sand below the steel pipe pile 1 And has a function of compressing it. Further, after the construction, when functioning as a pile for supporting a vertical load by an overlying structure or the like, the steel wing 10
The entire area of the portion protruding from the outer periphery of the steel pipe 2 functions as a support.

Second Embodiment In the first embodiment, the case where the steel wing 10 is constituted by the plate-making plates 10a and 10b having the sum of the internal angles of 360 ° by dividing the donut-shaped steel plate into a plurality of pieces is described. Is formed such that the sum of the inner angles of the steel plates 10a and 10b is smaller than 360 ° or larger than 360 °. FIG. 4 shows that the sum of the inner 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. 6 shows a steel plate 10.
The sum of the inner angles of a, 10b, and 10c is greater than 360 °, and an overlap 12 occurs between the steel plates 10a to 10c as shown in FIG.

According to the results of the field tests and numerical analysis conducted 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
°), the same thrust can be obtained, and by making the sum of the inner angles 540 ° or less, a larger thrust for pushing the steel pipe pile 1 downward can be obtained. It has been found that it is possible to smoothly penetrate even in the easily prone ground. For this reason, the sum of the inner angles of the steel plates 10a, 10b,.
It is better to be within the range of 0 °.

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
It is not necessary to make 2 equal in size or to be concentrated in one place, and they may be provided between the adjacent steel plates 10a, 10b,.

Third Embodiment FIG. 8 is a perspective view of a third embodiment of the present invention, and FIG. 9 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. The thick steel pipe 5
Instead, a strengthened steel pipe having a higher material strength than the steel pipe 2 may be used. 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.

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.

In this embodiment, for the portion of the steel pipe pile 1 which is affected by the bending stress, a strengthened steel pipe 5 thicker than the steel pipe 2 or a strengthened steel pipe having a higher strength than the steel pipe 2 is used. 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 plate thickness and height H ₁ of the strengthened steel pipe 5 are determined by numerical analysis in consideration of an 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 reinforcing steel pipe 5 thicker than the steel pipe 2 or a reinforcing 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 wall 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 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. 10A shows a disk-shaped steel bottom plate 6 joined to the tip of the steel pipe 2 by welding.
0 (b) is a steel pipe 2 in which a donut-shaped steel bottom plate 7 is welded to the tip of the steel pipe 2. FIG. 10 (c) shows a disk-shaped steel bottom plate 6 joined to the inside of the vicinity of the tip of the steel pipe 2 by welding, and FIG. 10 (d) shows a donut-shaped steel bottom plate 7 joined in the same manner. Things. The steel bottom plate 6,
7 may be attached to the lower end of the strengthened steel pipe 5 or its vicinity. Further, 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 opening at the tip 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
The total area of the steel wing 10 and the portion protruding from the outer periphery of the steel pipe 2 of the steel wing 10 functions as a support.

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. 6, the case where the steel wing 10 is constituted by the two steel plates 10a and 10b is shown. Should be two or more sheets, and preferably about two to four sheets.

Fifth Embodiment FIG. 11 is an explanatory diagram of the fifth embodiment. In this embodiment,
In driving the steel pipe pile 1 into the ground, the solidification material injection pipe 13 is inserted into the steel pipe pile 1 immediately before or after the striking, and the ground is inserted into the ground from the tip of the steel pipe pile 2 or the vicinity of the steel wing 10. For example, a solidifying material 14 such as cement milk, cement mortar, or liquid resin is injected into a lower portion of the steel pipe 2 (or the reinforcing steel pipe 5) and around the steel wing 10, and is integrated with the steel pipe pile 1. Thereby, when the steel pipe pile 1 is buried, the steel wing 1
The ground disturbed by 0 is strengthened, and a large supporting force can be obtained.

[0037]

EXAMPLE Next, an example of the present invention will be described with reference to FIG. 12 taking the steel pipe pile 1 of Embodiment 3 shown in FIG. 8 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 has a length of 500 mm, an outer diameter of 500 mm, and a thickness of 2 mm.
0 mm and the material was 50 kg steel. The outer diameter of the steel wing 10 was 1000 mm, the wall thickness was 40 mm, and it was constituted by two steel plates 10a and 10b. The sum of its inner angles was 330 ° to prevent clogging with cobblestones. The step between the steel plates 0a and 10b was 125 mm.

Further, 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. 16 and construction is performed, the steel pipe pile 1 can be buried in the ground smoothly and in a short time. Was. Further, after the embedding work, the steel pipe pile 1 was pulled out from the ground by reverse rotation, and the steel wing 10 was inspected, but no cobblestone was clogged. 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, since the sum of the inner angles of the steel plates 10a and 10b constituting the steel wing 10 is set to 330 °, it is possible to prevent the cobblestone from being clogged between the ends of the steel wing 10. We were able to.

Embodiment 6 By the way, when the outer diameter of the steel pipe 2 increases, the outer diameter of the steel blade 10 also increases 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 steel plates 10a, 10b of 0 are cut at sharp angles at the cut-in portions (ends on the rotation direction side) to provide an inclined surface 15, 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. 14, a digging blade 16 for assisting digging of the steel wings 10 is attached to the cut-in portions of the steel plates 10a and 10b.

Embodiment 7 FIG. 15 shows Embodiment 7 of the present invention.
In order to prevent the ends of the steel plates 10a, 10b of the steel wing 10 from being deformed when the steel pipe pile 1 is screwed into the ground and buried, the bite portions of the steel plates 10a, 10b are formed. And a reinforcing member 17 attached thereto.

[0042]

【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 parts is attached to the outer peripheral surface near the tip of the steel pipe at almost the same height, the same angle, and in the same direction, and the sum of the inner angles of the steel plate 315 ° C. to 54
The following effects can be obtained because the wings are made of steel wings in the range of 0 ° C.

(A) Since the 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 a plurality of steel plates constituting the steel wing to 315 ° or more, it is possible to prevent the boulder from being clogged between the beginning and the end of the steel wing, and moreover, to substantially make 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 screw-in type steel pipe pile of the above (1), the portion where the steel wing is to be attached is constituted by a strengthened steel pipe having a thickness greater than the thickness of the steel pipe above it or a strengthened steel pipe having a higher material strength than the steel pipe. Therefore, even if a large bending moment is transmitted from the steel blade, the stress level of the strengthened steel pipe can be suppressed to within an allowable value.

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

(4) In the screw-in type steel pipe pile according to the above (1), (2) or (3), immediately before or after the driving of the steel pipe pile driving, the steel pipe pile is moved into the ground from the front end portion or the vicinity thereof. Since the solidified material was injected and integrated with the steel pipe pile,
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 a second embodiment of the present invention.

FIG. 5 is a bottom view of FIG. 4;

FIG. 6 is a perspective view of another example of the second embodiment.

FIG. 7 is a bottom view of FIG. 6;

FIG. 8 is a perspective view of a third embodiment of the present invention.

FIG. 9 is a longitudinal sectional view of FIG.

FIG. 10 is a schematic diagram showing various examples of Embodiment 4 of the present invention.

FIG. 11 is an explanatory diagram of Embodiment 5 of the present invention.

FIG. 12 is an explanatory diagram of an embodiment of the present invention.

FIG. 13 is a perspective view of a sixth embodiment of the present invention.

FIG. 14 is a perspective view of another example of the sixth embodiment.

FIG. 15 is a perspective view of a seventh embodiment of the present invention.

FIG. 16 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-10c Steel plate 14 Solidified material

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

Claims (4)

[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 into a plurality of pieces substantially equal to the inner diameter of the steel pipe is attached to the outer peripheral surface near the tip of the steel pipe at substantially the same height, the same angle, and inclined in the same direction. And the sum of the inner angles of the steel plate is 315 ° C.
A screw-in type steel pipe pile comprising a steel wing in a temperature range of up to 540 ° C. 2. The steel pipe according to claim 1, wherein the steel wing mounting portion is formed of a strengthened steel pipe having a thickness greater than a thickness of a steel pipe above the steel wing or a strengthened steel pipe having a material strength higher than that of the steel pipe. Screwed steel pipe pile. 3. 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
Or the screw-in type steel pipe pile according to 2. 4. Immediately before or after the steel pipe pile is driven, 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 claim 1, 2 or 3.