JP4966836B2 - Steel pipe pile - Google Patents

Description

  The present invention relates to a steel pipe pile that is rotated and placed on the ground.

  As for the steel pipe pile which fixed the excavation blade | wing provided with the propulsion angle to the lower end part of the steel pipe by welding, many proposals are conventionally made by patent documents 1-7, and it is provided for practical use in this. There are also things.

  The technologies related to steel pipe piles that have been proposed in the past are all ideas related to the manner in which excavation blades are attached to steel pipes, and each proposed technology is a technology that can solve these problems or achieve the purpose. It can be said that there is.

However, both techniques have advantages and disadvantages. For example, the technique called increasing the mounting strength of a drilling blade to a steel pipe has the advantage that the desired result can be obtained with respect to the mounting strength, but to increase the mounting strength. This has led to new difficulties such as incurring the result of increasing the force required to bury the pile and lowering the ground reaction force support ability as a pile.
JP-A-7-173832 JP-A-10-280403 Japanese Patent Laid-Open No. 11-140871 JP 2001-3357 A JP 2001-348867 A Japanese Patent Application No. 2006-177125 Japanese Patent No. 3264910

  Therefore, in the present invention, it is possible to enter the ground straight without bending, but the force required for embedding may be smaller than that of the conventional product, and the support capacity of the ground reaction force after embedding may be superior to that of the conventional product. It is an object to provide a steel pipe pile that is not inferior.

The structure of the steel pipe pile of the present invention made for the purpose of solving the above problems is a flat disk body having a center hole with an inner diameter in consideration of the outer diameter of the steel pipe that becomes the steel pipe pile, at one place on the diameter. The cutting pipe is cut to give a propulsion angle, and a cutting blade is provided at the front end in the rotational direction of the cut portion to form the excavation blade, while two of the excavation blades are formed in the vicinity of the lower end portion of the steel pipe. With respect to the direction of rotation, the cutting blades of both excavation blades have a phase difference of 180 degrees and are welded to the steel pipe at the center hole.
In the present invention, in addition to the above-described configuration, a cap-shaped cone can be provided on the lower end surface of the steel pipe.

In the present invention, the two excavation blades may be fixed to the steel pipe with a pitch difference in the propulsion direction in addition to a phase difference in the rotation direction. An example of the pitch difference is a half pitch. In some cases, the excavation blades provided on the steel pipe are provided with a downward gradient (downward angle with respect to the horizontal plane) from the center side toward the outer periphery. In the case of two excavation blades having a pitch difference, it is sufficient to provide the lower excavation blade with a downward angle with respect to the horizontal plane.
Here, the cone having the same diameter as that of the steel pipe provided at the lower end surface of the steel pipe is preferably a cone from the viewpoint of embedding (propulsion) efficiency, but may be a pyramid or a plate-like cone. Some cones have bits attached.

In the present invention, a flat disk body having a center hole with an inner diameter considering the outer diameter of a steel pipe to be a steel pipe pile is cut at one place on the diameter to give a propulsion angle, and the cut A cutting blade is provided at the front end in the rotation direction of the section, and formed on the excavation blade. On the other hand, two of the excavation blades are positioned 180 degrees on the cutting blades of both excavation blades in the vicinity of the lower end of the steel pipe with respect to the rotation direction of the steel pipe. Since the steel pipe pile is formed by attaching the steel pipe to the steel pipe with a phase difference at the center hole, the resistance of the soil acting on one excavation blade can be distributed to the two excavation blades. it can. On the other hand, since there are two cutting blades, the force required for embedding is smaller than the conventional product. Moreover, since the two cutting blades are provided with a phase difference of 180 degrees in the rotation direction, the pile enters straightly. Further, in the case where a pitch difference is provided in the propulsion direction, the embedding (propulsion) efficiency with respect to the clayey ground is good. This is because if there is no pitch difference, the blades may slip and the piles may not be propelled or difficult to propel. In addition, because of the two-blade type of 360 degrees, it is possible to provide a steel pipe pile that is superior to conventional products in supporting capacity for ground reaction force.
In the steel pipe piles of the present invention, two 360-degree type drilling blades with the same outer shape and the same propulsion angle are phased 180 degrees and pitch differences are provided on the steel pipe piles. It is possible to effectively send out the soil to the ground side with the upper blades, whereby the rotational force acting on the steel pipe pile can be efficiently used for propulsion of the pile.

  Next, an embodiment of the steel pipe pile of the present invention will be described with reference to the drawings. 1 is a perspective view seen from the front side of the main part of an example of the steel pipe pile of the present invention, FIG. 2 is a plan view of the pile of FIG. 1, FIG. 3 is a bottom view of the pile of FIG. FIG.

  1-4, 1 is the pile main body by the steel pipe which forms this invention steel pipe pile, and only the lower end part vicinity of the steel pipe is shown in the figure. 2 is a cone formed on the lower end surface of the pile body 1, and the cone 2 here is a steel pipe made of an arrowhead-like plate, but may be formed as a cone or a pyramid. . When the cone 2 is plate-shaped, the lower end opening of the steel pipe is closed with a blind cover or the like.

  3 and 4 are disc bodies processed into a spiral ribbon shape to be excavation blades. That is, the disk bodies 3 and 4 are cut 3b and 4b at one location on the diameter of the steel flat plate in which the holes 3a and 4a having the hole diameter determined in consideration of the outer diameter of the pile body 1 are formed at the center. The cut portions 3b and 4b are processed into a ribbon shape in a direction away from each other on the central axes of the holes 3a and 4a. In this ribbon-like processing, by adjusting the distance between the cut portions 3b and 4b that are separated from each other in the vertical direction, the planar projected inner diameters of the spiral center holes 3a and 4a formed in the excavation blades are adjusted to the steel pipe. And adjusting the propulsion angle (pitch) of the excavation blades. As a result, the cutting edges 3c and 4c are formed at the front ends (as viewed from the rotation direction) of the cut portions 3b and 4b of the two disc bodies 3 and 4, respectively, and the two disc bodies 3 and 4 are spirally formed. The propulsion angle of the angle θ is given to the entire disk in a ribbon shape. Note that the outer diameter and the propulsion angle θ of the disc bodies 3 and 4 shown in FIG. 1 are exaggerated because they are schematic representations.

  That is, the two disc bodies 3 and 4 are formed into a spiral ribbon shape by separating the respective cut portions 3b and 4b in the vertical direction, and the two excavation blades 30 and 40 having the propulsion angle θ are formed. It is formed. In the present invention, although not shown, the disk bodies 3 and 4 are processed in a spiral ribbon shape with a propulsion angle θ so as to have a downward slope from the center side to the outer peripheral side of the disk surface. The ground reaction force can be more effectively supported by the vanes provided with the downward gradient. Thus, an example of the excavation blades 30 and 40 attached to the steel pipe pile of the present invention is formed.

  The excavation blades 30 and 40 are passed from the side of the central holes 3a and 4a near the lower end of the pile body 1, but first, one disk body 3 is temporarily fixed to a predetermined position by welding through a steel pipe, Thereafter, the other disc body 4 is rotated so as to sew between the propulsion angles θ of the disc body 3, and positioned so that the cutting edges 3c and 4c of the two disc bodies 3 and 4 are separated by 180 degrees. Then, the center holes 3a and 4a of the disc bodies 3 and 4 and the outer surface of the steel pipe 1 are permanently fixed by welding. That is, the two excavation blades 30 and 40 illustrated in the figure are formed on the pipe wall of the steel pipe forming the pile body 1 with a phase difference of 180 degrees in the rotation direction on the upper and lower surfaces of each blade 30 and 40. It is fixed by welding with the welding line W of the book. In the present invention, although not shown, the blades 30 and 40 may be attached with an appropriate pitch difference in addition to the above phase difference.

  Since the lower end surface of the steel pipe and the lower surface of the blade 30 remain exposed at the lower end of the pile body 1 to which the excavation blades 30 and 40 are welded, even if the inclined surface of the blade is given a propulsion angle, There is great resistance to propulsion while rotating in the soil. Therefore, in the present invention, on the lower surface side of the excavating blades 30 and 40, coaxial with the central axis of the pile body 1, instead of the blind lid and the arrow-shaped cone 2, the cone cone made of steel plate is used. May be attached by welding with the top facing down. A bit for excavation may be provided on the outer surface of the cone-shaped cone. In this way, the excavation propulsion force is further increased, and the steel pipe pile can easily enter straight into the ground.

  The above steel pipe pile has a cone-shaped cone at the lowermost end of the pile body 1 and has the drilling blades 30 and 40 inclined downward on the cone body. When a rotational force is applied while applying a pressing force, the excavation force is applied to almost the entire surface where the components of the pile abut against the soil in the direction in which the steel pipe pile enters due to the cooperative action of the cone cone and the excavation blades 30 and 40. Can be demonstrated.

  In the pile according to the present invention, in the excavation blades 30 and 40 welded to the steel pipe with a pitch difference, the earth and sand excavated by the excavation blade 30 and sent to the upper surface side of the blade 30 is efficiently grounded by the second excavation blade 40. Sent to the side. In addition, the cutting grounds 3c and 4c are not slipped on the clay-like ground, and the soil is efficiently cut and buried (promoted).

  The second excavation blade 40 provided with a pitch difference is given the same propulsion angle as the excavation blade 30 of the first blade and has substantially the same form as the excavation blade 30, but the second excavation blade 40 is an excavation blade. The spiral drawn by the propulsion angle given to 30 is arranged with a half pitch difference as an example, and is fixed by welding in the center hole 4a. The positions of the cutting blades 3c and 4c of both the excavating blades 30 and 40 are arranged so as to have a phase difference of 180 degrees in the rotation direction when viewed from the plane. Thus, since the cutting blades 3c and 4c are symmetrically arranged with respect to the center of the pile, the pile can enter straight into the ground without bending.

  In the steel pipe pile of the present invention, the second excavation blade 40 crawls the earth and sand fed out to the ground side by the excavation blade 30 by the second excavation blade 40 which is kept behind with respect to the rotation direction and the propulsion direction of the excavation blade 30. Since it sends out upward, the propulsion (burial) of the pile becomes smoother.

  The present invention is as described above, and a 360-degree disc body having a center hole with an inner diameter considering the outer diameter of a steel pipe that becomes a steel pipe pile is cut at one place on the diameter, and the cut portion is vertically oriented. And adjusting the diameter of the mounting hole to the steel pipe, and forming a drilling blade at the front end in the rotational direction on the lower side of the cut portion, forming two blades, In the vicinity of the lower end of the steel pipe, a steel pipe pile is attached to the steel pipe at the center hole with a phase difference of 180 degrees between the blades of both blades in the direction of rotation of the steel pipe and a half pitch difference in the propulsion direction of the steel pipe. Then, the mounting strength of the excavation blades is sufficiently high, and since it can enter straight into the soil, the force required for embedding may be smaller than the conventional product, and the support capacity of the ground reaction force is also two pieces Because it has a blade, than the conventional product It is possible to provide a steel pipe piles.

The perspective view seen from the front side of the principal part of an example of this invention steel pipe pile. The top view of the pile of FIG. The bottom view of the pile of FIG. The front view of the pile of FIG.

Explanation of symbols

1 Pile body 2 Cone 3, 4 Disc body
3a, 4a Center hole
3b, 4b cut part
3c, 4c cutting edge
30, 40 drilling blades

Claims (4)

  A plate-like disk body with a center hole with an inner diameter taking into account the outer diameter of the steel pipe that becomes the steel pipe pile is cut at one place on the diameter to give a propulsion angle, and the rotation direction of the cut part A cutting blade is provided at the front end to form the excavation blade, and two of the excavation blades are provided with a phase difference of 180 degrees between the cutting blades of both excavation blades in the vicinity of the lower end of the steel pipe with respect to the rotation direction of the steel pipe. A steel pipe pile which is welded and fixed to the steel pipe at the center hole.   The steel pipe pile according to claim 1, wherein the two excavation blades are fixed to the steel pipe with a phase difference in a rotation direction and a pitch difference in a propulsion direction.   The steel pipe pile according to claim 1 or 2, wherein the excavation blade is provided with a downward gradient (downward angle with respect to a horizontal plane) from the center side toward the outer periphery.   The steel pipe pile in any one of Claims 1-3 which provided the cone with the same diameter as the said steel pipe at the maximum in the lower end surface of the steel pipe.

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