JP2009001966A - Steel pipe pile with blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel pipe pile with a blade constituted by attaching the blade to an end of a steel pipe or its vicinity, the steel pipe being inserted and buried into the ground by giving rotational force to the steel pipe, and sharing stress efficiently for the bending moment acting on it. <P>SOLUTION: In this steel pipe pile with the blade, a blade mounting plate 10 is attached to a mounting part 4 provided in the tip part of the steel pipe 3 by welding, and the blade 5 is attached to the blade mounting plate 10 by bolts 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a steel pipe pile with wings that is embedded in the ground by the wood screw action of a wing by attaching a wing to the tip of the steel pipe or in the vicinity thereof and applying a rotational force to the steel pipe.

  As a winged steel pipe pile embedded in the ground by the wood screw action of the wing (blade, blade) by attaching a wing (blade, blade) to the tip of the steel pipe or in the vicinity thereof and applying a rotational force to the steel pipe, For example, the following has been proposed.

  The steel pipe pile described in Patent Document 1 is provided with a blade having an inclined front surface for pushing extending in the vertical direction at the lower part of a steel cylindrical body, and is inclined obliquely from the lower end portion of the inclined front surface toward the rear in the rotational direction of the cylindrical body. An inclined drill head is fixed to an annular drill head, and a lower end portion of a steel pipe pile is attached to an upper end portion of the drill head. In this structure, a narrow arc-shaped inclined blade provided at the bottom of the steel cylinder is cut into the ground, and a small amount of soil corresponding to the cross-sectional area of the cylinder is laterally moved by the inclined inclined front surface for pushing. The press-in speed can be increased with the same press input as compared with the conventional rotary press-fit pile, and a small press input is sufficient with the same press-in speed. Moreover, since a pile body is an open end state, soil can be taken in in a pipe | tube and the improvement of workability can be expected.

  The steel pipe pile described in Patent Document 2 includes a spiral blade at the tip, an outer diameter that is approximately 1.5 to 3 times the outer diameter of the steel pipe, and an inner diameter that is approximately 0.4 to 0.9 times the inner diameter of the steel pipe pile. The doughnut-shaped steel sheet is cut at one or a plurality of locations, and is concentrically welded and fixed to the end of the steel pipe pile that has been cut into a spiral shape, and the spiral blades are projected to the inside and outside of the steel pipe pile tip, and the spiral The angle between the part of the steel pipe pile protruding from the outer periphery of the steel pipe pile and the steel pipe pile main body is configured to be substantially perpendicular, and the thickness of the blade is set in the radial direction in accordance with the distribution of bending moment generated in the blade. The structure is changed. The plate thickness of the spiral blades does not need to be the same as the whole, but in order to change the thickness in the radial direction of the blades according to the bending moment generated by the force acting on the blades, two portions close to the steel pipe are stacked The blade thickness is continuously changed by casting or the like.

In the steel pipe pile described in Patent Document 3, a part of a tubular pile member is inserted into the other tubular pile member, the spiral blades formed on the outer peripheral surfaces of both tubular pile members are combined, and the combined spiral blades are combined. It is tightened with bolts and nuts. Both the tubular pile members can be connected by tightening the spiral wings of the combined tubular pile members with bolts and nuts, so that the workability of the connection is good.
JP 61-098818 A JP 2001-193063 A Japanese Patent Application Laid-Open No. 11-181761

  However, the steel pipe piles described in Patent Documents 1 to 3 have the following problems.

  The steel pipe pile described in Patent Document 1 has a small projecting amount from the pile body of the inclined blade, so that the propulsive force for penetrating the pile body into the ground is insufficient, and it is difficult to penetrate with a hard support layer, etc. There is a problem that the vertical bearing capacity after pile penetration becomes small. Also, if the overhang width of the inclined blade from the pile body is increased, the bending moment acting on the pile body from the inclined blade will also increase, and in order to withstand this, an annular drill head with a larger plate thickness must be prepared. In other words, there is a problem that the material cost will rise.

  In the steel pipe pile described in Patent Document 2, when the blades are stacked on two sheets, the weld length becomes long, and the increase in cost cannot be avoided. In addition, it is possible to weld the part that protrudes outside the steel pipe, but the extension part of the inner part of the steel pipe can be welded only from the inner surface, and the blade part is connected using a single pipe, greatly improving work efficiency. To drop. If the overhang on the lower blade is made smaller with respect to the upper blade attached to the steel pipe, welding can be performed from the outside, but the balance of the bending moment due to the action of the ground reaction force becomes worse and the structure becomes unstable. turn into.

  The steel pipe pile described in Patent Document 3 must weld two blades to the side surface, and when a blade is attached to the side surface, a larger bending moment acts than the blade subjected to the ground reaction force, There is a problem that the plate thickness must be increased. Moreover, in this structure, since two annular members overlap, there also exists a problem which steel weight will increase.

  The present invention has been made in order to solve the above-described problems. A blade is attached to the tip of a steel pipe or the vicinity thereof, and a blade with a wing is embedded in the ground by applying a rotational force to the steel pipe. In a steel pipe pile, the winged steel pipe pile which can bear a stress efficiently with respect to the bending moment which acts is provided.

  According to the FEM analysis conducted by the inventor, when embedding in the ground while applying rotational force to the winged steel pipe pile, when the wing receives a reaction force from the ground, the wing attachment part (root of the wing) It was confirmed that the stress of the part) was the largest, the stress at the tip of the blade (the overhanging end of the blade) was small, and the transmission of bending stress to the steel pipe was also observed. Therefore, if the attachment part of the wing to the steel pipe (the connection part between the steel pipe and the wing) is reinforced by the auxiliary member, the stress at the connection part between the steel pipe and the wing can be reduced, and the bending stress transmitted to the steel pipe can also be reduced. I thought. As a result, it is possible to use blades with a smaller overall thickness than blades used in conventional steel pipe piles with blades, and the strength of the blades is effectively increased by making the generated stress as uniform as possible. Therefore, the material cost can be reduced.

  Based on the above concept, the present invention has the following features.

  [1] In a steel pipe pile with wings, in which a wing is attached at or near the tip of the steel pipe, and embedded in the ground by applying a rotational force to the steel pipe, an attachment member between the steel pipe and the wing is used as an auxiliary member. Winged steel pipe pile characterized by being reinforced by.

  [2] The auxiliary member is a wing mounting plate, the wing mounting plate is mounted on the steel pipe, and the wing is mounted on the wing mounting plate by bolt joining. Winged steel pipe pile.

  [3] The bladed steel pipe pile according to [2], wherein a blade mounting plate is attached to the steel pipe by welding.

  [4] The bladed steel pipe pile according to [2], wherein a blade mounting plate is attached to the steel pipe with a bolt.

  [5] The winged steel pipe pile according to [1], wherein the auxiliary member is a reinforcing plate, and a wing is directly attached to the steel pipe, and the attachment portion is reinforced by the reinforcing plate.

  [6] The winged steel pipe pile according to any one of [1] to [5], wherein the outer diameter of the wing is 1.2 to 3 times the diameter of the steel pipe.

  [7] With the blade according to any one of [1] to [6], wherein the inner diameter of the blade is 0.25 to 0.9 times the diameter of the steel tube, and an opening is provided at the tip of the steel tube. Steel pipe pile.

  In the present invention, since the connecting portion of the steel pipe and the blade (the attachment portion of the blade to the steel pipe) on which the bending moment acts greatly is reinforced by the auxiliary member, the substantial plate of the blade at the connecting portion of the steel pipe and the blade. The thickness can be increased, the stress can be efficiently applied to the bending moment, and the bending moment can be appropriately handled. At that time, since it is not necessary to increase the thickness of the entire blade, the material cost can be reduced and the production delivery time can be shortened. Further, when the steel pipe is transported to the construction site, since the wings can be freely removed, the steel pipe can be efficiently loaded without being bulky. In addition, wings can be easily attached and removed at construction sites, and changes and troubles can be dealt with quickly.

  Embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
1 to 3 are schematic views showing a winged steel pipe pile according to Embodiment 1 of the present invention. FIG. 1 is a perspective view, FIG. 2 is a longitudinal sectional view, and FIG. 3 is a plan view. 1-3, 2 is a steel pipe pile with a wing | blade (henceforth only a steel pipe pile), 3 is a steel pipe, 5 is a wing | blade, 10 is a board for wing | blade attachment (auxiliary member), 20 is a volt | bolt. FIG. 1B shows the tip of the steel pipe 3 before the blade 5 and the blade mounting plate 10 are mounted upside down.

  As shown in FIGS. 1-3, in the winged steel pipe pile 2 which concerns on this Embodiment 1, the two attachment parts 4 of the letter shape are provided in the front-end | tip part of the steel pipe 3, A blade mounting plate 10 formed in a shape obtained by dividing a donut into two in the circumferential direction is attached obliquely by welding. The wings 5 (wings 5 a and 5 b) formed in a semicircular shape by dividing the disk into two are attached to the respective wing mounting plates 10 by bolts 20.

  Here, the shape, structure, and mounting position of the blade mounting plate 10, the blade 5 and the mounting portion 4 are not particularly limited, and a flat plate, a spiral bent shape, It can be selected as appropriate, for example, by connecting flat plates.

  The wing mounting plate 10 only needs to have an overhang width that allows the wing 5 to be connected by the bolt 20, and the overhang width of about 30 mm to 200 mm is desirable. This is appropriately changed depending on the size of the bolt 20 to be used and the outer diameter of the steel pipe 3.

  The bolts 20 are attached at a pitch of 10 to 45 °, depending on the outer diameter of the steel pipe 3 and the outer diameter of the blade 5. At that time, since the blades used for the steel pipe pile with wings are generally thick, the heads and nuts of the bolts 20 can be embedded in the wings 5 so as not to increase unnecessary resistance during the rotation penetration. can do. Alternatively, if the screw part, nut, or head of the bolt 20 is positively projected below the blade 5, the role of the auxiliary excavation blade during rotation penetration can be expected, and the penetration performance is improved. It becomes possible.

  In addition, you may install discontinuously only in the position which connects the board 10 for wing | blade attachment with the volt | bolt 20. FIG.

  And although the outer diameter of the wing | blade 5 changes with conditions of the ground which embeds the steel pipe pile 2, the outer diameter of the steel pipe 3, etc., generally 1.2 to 3 times the outer diameter of the steel pipe 3 is desirable.

  In addition, when an opening is formed between the blade 5a and the blade 5b, if a closing plate is attached to the opening, it is possible to prevent the intrusion of earth and sand into the tube, and the hollow portion in the tube can be used for underground heat. It can be used effectively for other purposes.

  Further, the blades 5 and the blade mounting plate 10 may be connected in multiple stages as necessary. Further, the wing 5 and the wing mounting plate 10 may be divided into four in the circumferential direction, and each may have four.

  And when constructing using a winged steel pipe pile as described above, using a motor that rotates the pile head or pile body, etc., using the propulsive force of the wing 5 and rotating in the manner of a wood screw Let

  In this way, in the first embodiment, the connection portion (attachment portion of the blade 5 to the steel tube 3) 4 between the steel tube 3 and the blade 5 on which a large bending moment acts is provided via the blade attachment plate 10. Since the blade 5 is attached to the steel pipe 3, the substantial plate thickness of the blade 5 at the attachment portion of the blade 5 to the steel pipe 3 (the root portion of the blade 5) can be increased, and the bending moment can be efficiently improved. Stress can be borne. As a result, even if the large blade 5 is attached to the tip of the steel pipe 3, the bending moment does not cause the stress to exceed the allowable value and adversely affect the support force. Obtainable. In addition, since the wing 5 is joined to the wing mounting plate 10 with the bolt 20, it is possible to reduce the welding cost, and it is not necessary to increase the plate thickness of the entire wing. The delivery time can be shortened.

[Embodiment 2]
FIG. 4 is a longitudinal sectional view showing a winged steel pipe pile according to Embodiment 2 of the present invention.

  In the second embodiment, the basic configuration is the same as that of the first embodiment, but the steel pipe 3 and the blade mounting plate 10 are joined by bolts 21.

  The blade mounting plate 10 according to the second embodiment has a member formed in a shape obtained by dividing a donut in the circumferential direction, and rises upward from the surface of the member, and substantially contacts each of the outer peripheral surface and the inner peripheral surface of the steel pipe 3. It is comprised from the member formed in the shape which touches.

  By using such a bolt joint, the connection portion of the steel pipe 3 and the blade mounting plate 10 can be made to have a structure close to a hinge, and transmission of bending stress to the steel pipe 3 is reduced. The need to increase is reduced. Further, since there is no weld joint between the steel pipe 3 and the blade mounting plate 10 in addition to between the blade mounting plate 10 and the blade 5, the blade 5 can be appropriately changed when the blade 5 is damaged or when the propulsive force is insufficient. It becomes possible, the degree of freedom in field construction increases, and it becomes possible to respond quickly to troubles. Furthermore, the welding cost can be further reduced.

[Embodiment 3]
5 and 6 are schematic views showing a winged steel pipe pile according to Embodiment 3 of the present invention, FIG. 5 is a longitudinal sectional view, and FIG. 6 is a plan view.

  In this third embodiment, the basic configuration is the same as in the first or second embodiment, but by making the inner diameter of the blade 5 0.25 to 0.9 times the outer diameter of the steel pipe 3. The opening 6 is provided at the tip of the steel pipe pile 2. At that time, if the opening 6 is enlarged, a large amount of earth and sand can be taken into the steel pipe and the workability is improved. However, if the opening 6 is enlarged too much, the supporting force may be lowered. In consideration of the above, the size of the opening 6 (inner diameter of the blade 5) is appropriately selected.

  Further, by making the sum of the inner angles of the blades 5a and 5b smaller than 360 °, the opening of the stepped portion formed between the circumferential end of the blade 5a and the circumferential end of the blade 5b is increased, If it is configured so as to pass through a large gap, the workability is further improved.

  Thus, the opening 6 at the tip of the pile allows for simultaneous excavation using an auger, and by injecting a curable fluid from the tip of the auger, The strength of the part can also be strengthened.

[Embodiment 4]
FIG. 7 is a longitudinal sectional view showing a winged steel pipe pile according to Embodiment 4 of the present invention. In FIG. 7, 2 is a steel pipe pile with wings, 3 is a steel pipe, 5 is a wing, 30 is a reinforcing plate (auxiliary member), and 20 is a bolt.

  In the winged steel pipe pile 2 according to the fourth embodiment, two L-shaped attachment portions 4 are provided at the distal end portion of the steel pipe 3, and each of the attachment portions 4 is divided into two discs in a semicircular shape. A formed wing 5 is attached. A reinforcing plate 30 is attached to the lower surface of the wing near the attachment portion 4 with bolts 20.

  In this way, by providing the reinforcing plate 30 in the vicinity of the attachment portion 4 of the blade 5 to the steel pipe 3 (connection portion between the steel tube 3 and the blade 5), the stress generated by the bending moment is reduced, and a large blade is used to increase the stress. The tip support force can be obtained, and the same operation and effect as in the case of the first embodiment can be obtained.

  In the fourth embodiment, the blades 5 are directly attached to the steel pipe 3. However, similarly to the first embodiment, the blade attachment plate 10 is attached to the attachment portion 4 of the steel pipe 3, and the blades 5 are attached to the blade attachment plate 10. Further, the reinforcing plate 30 may be attached to the lower surface of the wing 5 with bolts.

[Embodiment 5]
FIG. 8 is a longitudinal sectional view showing a winged steel pipe pile according to Embodiment 5 of the present invention.

  The steel pipe pile with wings according to the fifth embodiment is a case where the wings 5 are attached to the side surfaces (outer peripheral surfaces) of the steel pipes 3 and are connected using bolts 20 via the wing attachment plates 10. The blade attachment plate 10 according to the fifth embodiment is a member having a longitudinal section that is substantially L-shaped, and is attached to the upper and lower surfaces of the blade 5. As a result, the bending stress transmitted from the wing 5 subjected to the ground reaction force can be relaxed by the wing mounting plate 10.

  An example of the construction test in the case of embedding the winged steel pipe pile which concerns on this invention in the ground is shown. In addition, the winged steel pipe pile 2 which concerns on said Embodiment 1 was used here. The dimensions of the steel pipe 3 are an outer diameter D: 1000 mm, a plate thickness: 15 mm, a length: 30 m, and a blade mounting plate 10 formed in a donut shape is attached to the tip part (attachment part) 4 of the steel pipe 3 by welding, A blade 5 having a blade diameter of 2000 mm obtained by dividing the disk into two was connected to the blade mounting plate 10 by a bolt 20. The plate thickness of the blade mounting plate 10 was 25 mm, and the overhang width was 50 mm. The plate thickness of the blade 5 was 15 mm.

  And as a result of rotating this winged steel pipe pile 2 with a construction machine, it was able to construct like a normal winged steel pipe pile. After construction, when this winged steel pipe pile 2 was pulled out, it was confirmed that the steel pipe 3 and the wing 5 were not deformed at the attachment portion (the base portion of the wing 5), and the construction was completed in a healthy state.

It is a perspective view of a winged steel pipe pile concerning Embodiment 1 of the present invention. It is a longitudinal cross-sectional view of the winged steel pipe pile which concerns on Embodiment 1 of this invention. It is a top view of the winged steel pipe pile concerning Embodiment 1 of the present invention. It is a longitudinal cross-sectional view of the winged steel pipe pile which concerns on Embodiment 2 of this invention. It is a longitudinal cross-sectional view of the winged steel pipe pile which concerns on Embodiment 3 of this invention. It is a top view of the winged steel pipe pile which concerns on Embodiment 3 of this invention. It is a longitudinal cross-sectional view of the winged steel pipe pile which concerns on Embodiment 4 of this invention. It is a longitudinal cross-sectional view of the winged steel pipe pile which concerns on Embodiment 5 of this invention.

Explanation of symbols

2 Steel pipe pile with wing 3 Steel pipe 4 Attached part of wing to steel pipe (connection part of steel pipe and wing)
5 Wings 6 Openings 10 Wings Mounting Plates 20 Bolts 21 Bolts 30 Reinforcing Plates

Claims (7)

  In a winged steel pipe pile that is attached to the tip of the steel pipe or in the vicinity thereof, and is embedded in the ground by applying a rotational force to the steel pipe, the attachment part between the steel pipe and the wing is reinforced by an auxiliary member. Winged steel pipe pile characterized by that.   2. The winged steel pipe pile according to claim 1, wherein the auxiliary member is a wing attachment plate, wherein a wing attachment plate is attached to the steel pipe, and the wing is attached to the wing attachment plate by bolt joining. .   The winged steel pipe pile according to claim 2, wherein a wing mounting plate is attached to the steel pipe by welding.   The winged steel pipe pile according to claim 2, wherein a wing mounting plate is attached to the steel pipe with a bolt.   2. The winged steel pipe pile according to claim 1, wherein the auxiliary member is a reinforcing plate, and a wing is directly attached to the steel pipe, and the attachment portion is reinforced by the reinforcing plate.   The winged steel pipe pile according to any one of claims 1 to 5, wherein the outer diameter of the wing is 1.2 to 3 times the diameter of the steel pipe.   The winged steel pipe pile according to any one of claims 1 to 6, wherein the inner diameter of the wing is 0.25 to 0.9 times the diameter of the steel pipe, and an opening is provided at the tip of the steel pipe.

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