Steel pipe pile tip member

Abstract

To provide a steel pipe pile tip member used for a steel pipe pile supporting a structure such as a building on soft ground, which can be manufactured inexpensively, exhibits good penetration performance even in hard bedrock, and has excellent durability. [Solution] A steel pipe pile tip member 10 attached to the tip of a cylindrical steel pipe pile 100 that rotates and penetrates vertically into the ground is composed of an expansion section 14 on the outside of the tip and a tip reinforcing plate 16 attached to the tip of the expansion section 14 on the rotational penetration side of the steel pipe pile 100, thereby providing a steel pipe pile tip member 10 with good durability and penetration performance.

Description

[Technical Field]

[0001] The present invention relates to a steel pipe pile tip member that is used by being connected to the tip of a steel pipe pile that is used to support a structure such as a building on soft ground or the like. [Background technology]

[0002] Generally, when constructing a building or the like on a site where the ground is soft and the bearing capacity of the ground is insufficient, piles are driven into the ground to improve the bearing capacity of the ground.

[0003] Piles are classified into wooden piles, concrete piles, and steel pipe piles depending on the material, but the present invention relates to steel pipe piles.

[0004] Steel pipe piles often have a spiral tip at the tip to ensure high bearing capacity. The spiral tip attached to the steel pipe pile is often manufactured by processing a steel plate and is usually attached to the steel pipe pile by welding.

[0005] The steel pipe pile with the spiral tip attached is rotated by heavy machinery and driven into the ground. During this process, the spiral tip acts like a screw in the ground as it rotates and penetrates into the ground.

[0006] Generally, when steel pipe piles are used in soft ground, even for residential detached houses, several dozen piles are used, so a spiral tip member that has high rotational penetration performance while keeping manufacturing costs down is required. For example, a steel pipe pile tip member such as that shown in Patent Document 1 has been proposed. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-68647 Summary of the Invention [Problem to be solved by the invention]

[0008] According to Patent Document 1, it is possible to form the tip member, blocking plate, and excavation blade portion by using a single circular steel plate and making the minimum necessary cuts to that steel plate.By using this configuration, it is possible to manufacture a steel pipe pile tip member at a relatively low cost while still having sufficient bearing capacity.

[0009] The tip member of the steel pipe pile in Patent Document 1 does not pose any particular problems if the ground is relatively soft. However, the ground may contain gravel or rocks, and attempting to rotary-penetrate a steel pipe pile into such ground can result in wear and deformation of the tip member, and the stress generated during rotary penetration can be concentrated at the joints between the tip member, the closure plate, and the steel pipe, causing fractures in the welds.

[0010] If the tip becomes worn, deformed, or broken, the steel pipe pile may spin freely and not penetrate any further when rotated. As a result, the steel pipe pile must be pulled out and a new pile rotated and inserted again, which increases costs and delays the process.

[0011] In view of these problems, the present invention aims to provide a steel pipe pile tip member that can be manufactured inexpensively and has higher durability than the steel pipe pile tip members used in conventional steel pipe piles. [Means for solving the problem]

[0012] (1) The steel pipe pile tip member of the present invention is a steel pipe pile tip member attached to the tip of a cylindrical steel pipe pile that rotates and penetrates vertically into the ground, and is characterized in that it is composed of an expansion section attached to the outside of the tip of the steel pipe pile, and a tip reinforcing plate attached to the tip of the expansion section on the rotational penetration side of the steel pipe pile.

[0013] (2) The steel pipe pile tip member according to the present invention is characterized in that, in the steel pipe pile tip member according to (1), the tip reinforcing plate has a triangular shape.

[0014] (3) Furthermore, the steel pipe pile tip member of the present invention is characterized in that, in the steel pipe pile tip member described in (1) or (2), the tip reinforcement plate has a length of the longest side that is 85% or less of the radius of the expansion portion.

[0015] (4) Furthermore, the tip member of the steel pipe pile according to the present invention is characterized in that, in the tip member of the steel pipe pile described in any one of (1) to (3), the steel pipe pile is provided with a blocking plate at its tip opening, and the expansion portion and the blocking plate are connected at least at one point.

[0016] (5) The tip member of a steel pipe pile according to the present invention is characterized in that, in the tip member of a steel pipe pile described in any one of (1) to (4), the tip reinforcing plate is installed at an angle of 7 to 20 degrees from the horizontal to the penetration direction.

[0017] (6) Furthermore, the steel pipe pile tip member according to the present invention is characterized in that, in the steel pipe pile tip member described in any one of (1) to (5), the tip reinforcing plate is provided with a spacer between the tip reinforcing plate and the closing plate.

[0018] (7) Furthermore, the steel pipe pile tip member of the present invention is characterized in that, in the steel pipe pile tip member described in any one of (1) to (6), the closing plate has an auxiliary excavation member, and the tip portion of the auxiliary excavation member is positioned at a position rotated approximately 180 degrees from the tip portion of the tip reinforcement plate around the closing plate. [Effects of the Invention]

[0019] According to the steel pipe pile tip member described in (1), it is possible to provide a steel pipe pile tip member that can be manufactured inexpensively and has improved durability by attaching a tip reinforcing plate to the tip of the expansion section attached to the outside of the tip of the steel pipe pile.

[0020] According to the steel pipe pile tip member described in (2), by making the tip reinforcement plate triangular in shape, when the pile is rotated and penetrated into the ground, the force generated during the rotational penetration can be concentrated at the tip of the triangular tip reinforcement plate, which makes it possible to crush gravel and rocks and demonstrate high penetration performance.

[0021] According to the steel pipe pile tip member described in (3), it is possible to manufacture steel pipe pile tip members inexpensively by utilizing scrap wood generated during the manufacturing of the steel pipe pile expansion section without compromising durability and penetration performance.

[0022] According to the steel pipe pile tip member described in (4), by providing a blocking plate and connecting the expansion section to the blocking plate, the strength of the steel pipe pile tip member can be improved, and deformation of the steel pipe pile tip member when penetrating hard ground can be suppressed.

[0023] According to the steel pipe pile tip component described in (5), it is possible to achieve both high durability and maintaining penetration performance by setting the installation angle of the tip reinforcement plate from the horizontal to the penetration direction at 7 to 20 degrees. In particular, the results of the rotational penetration test showed that the highest durability and penetration performance could be achieved by setting the installation angle of the expansion section at 7 to 14 degrees from the horizontal to the penetration direction and setting the tip reinforcement plate at an angle of +0 to +6 degrees relative to the angle of the expansion section, that is, in the range of 13 degrees plus or minus 6 degrees.

[0024] According to the steel pipe pile tip member described in (6), the strength of the tip reinforcing plate can be further improved by providing a spacer between the tip reinforcing plate and the closing plate.

[0025] According to the steel pipe pile tip member described in (7), the blocking plate has an auxiliary excavation member, and the tip portion of the auxiliary excavation member is positioned at a position rotated approximately 180 degrees from the tip portion of the tip reinforcement plate around the blocking plate, thereby ensuring a stable installation state with the ground when starting rotational penetration into the ground and making it possible to start stable rotational penetration. [Brief explanation of the drawings]

[0026] [Figure 1]FIG. 2 is a schematic side view of the tip member of the steel pipe pile. [Figure 2] FIG. 2 is a schematic side view of the tip member of the steel pipe pile. [Figure 3] FIG. 2 is a schematic diagram of the tip member of a steel pipe pile viewed from the bottom. [Figure 4] FIG. 2 is a schematic diagram of the tip member of a steel pipe pile viewed from the bottom. [Figure 5] FIG. 2 is a schematic diagram of a tip reinforcing plate. DETAILED DESCRIPTION OF THE INVENTION

[0027] Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. These embodiments are merely examples for facilitating understanding of the invention, and unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0028] (First embodiment)

[0029] Figure 1 is a schematic side view of a steel pipe pile tip member 10 according to a first embodiment. The steel pipe pile tip member 10 is provided with a closure plate 12 at the tip of the steel pipe pile 100, and is fitted with a flared section 14 that is attached to the outside of the steel pipe pile 100 and is connected to the closure plate 12 at at least one point. The flared section 14 is a circular plate machined into a spiral shape and is attached to the steel pipe pile 100 by welding.

[0030] By constructing the closure plate 12 and the expansion section 14 so that they are connected at least at one point, it is possible to reduce the cost of manufacturing the steel pipe pile tip member 10, and it is also possible to reduce the effort required to attach the closure plate 12 and the expansion section 14 to the steel pipe pile 100.

[0031] A tip reinforcing plate 16 is attached to the tip of the flared portion 14 by welding, and the portion where the tip reinforcing plate 16 contacts the closure plate 12 is also fixed by welding.

[0032] Furthermore, an auxiliary excavation member 18 is attached by welding onto the closure plate 12. The tip of this auxiliary excavation member 18 is preferably attached at a position rotated approximately 180 degrees from the tip of the tip reinforcement plate 16 and the center of the closure plate 12. This allows the steel pipe pile 100 to stand almost upright relative to the ground surface when it is installed on the ground to be rotary penetrated into the ground, making it possible to start stable rotary penetration.

[0033] FIG. 2 is a schematic side view of the steel pipe pile tip member 10 according to the first embodiment, rotated 90 degrees from FIG.

[0034] 1 in that a spacer 20 is provided between the closure plate 12 and the tip reinforcing plate 16. The spacer 20 is fixed between the closure plate 12 and the tip reinforcing plate 16 by welding.

[0035] When the steel pipe pile 100 is rotated and driven into the ground, a strong force is applied to the tip reinforcement plate 16, especially when it comes into contact with rocks or the like. By providing the spacer 20, it is possible to improve the strength of the tip reinforcement plate 16 against deformation and prevent deformation during rotation and driving.

[0036] The tip reinforcing plate 16 is preferably attached at an angle of 7 to 20 degrees from the horizontal to the penetration direction.

[0037] If the attachment angle of the tip reinforcing plate 16 is too large, the steel pipe pile 100 will encounter great resistance from the ground when it is rotated and penetrated, increasing the possibility of the steel pipe pile 100 being damaged.

[0038] Conversely, if the angle at which the tip reinforcing plate 16 is attached is too small, the resistance from the rotary penetration ground to the steel pipe pile 100 is small, and although the possibility of breakage is reduced, this leads to a decrease in work efficiency.

[0039] According to the results of the rotational penetration test, the highest durability and penetration performance were achieved when the installation angle of the flared section 14 was set to 7 to 14 degrees from the horizontal in the penetration direction, and the tip reinforcing plate 16 was set to +0 to +6 degrees with respect to the angle of the flared section 14. In other words, it is preferable to install the tip reinforcing plate 16 within a range of 13 degrees ±6 degrees from the horizontal in the penetration direction.

[0040] Figure 3 is a schematic diagram of the steel pipe pile tip member 10 according to the first embodiment, viewed from the bottom. As shown in Figure 3, the tip reinforcing plate 16 covers the area from the center of the closure plate 12 to the end of the flared section 14. A spacer 20 is attached between the tip reinforcing plate 16 and the closure plate 12.

[0041] The tip reinforcing plate 16 and the spacer 20 enable the steel pipe pile 100 to have both good durability and penetration performance.

[0042] An auxiliary excavation member 18 is attached by welding onto the closure plate 12. It is desirable that the tip of this auxiliary excavation member 18 be attached at a position rotated approximately 180 degrees from the tip of the tip reinforcing plate 16 around the closure plate 12.

[0043] By attaching the tip reinforcement plate 16 and auxiliary excavation member 18 at this position, when the steel pipe pile 100 is placed on the ground to begin rotary penetration, the steel pipe pile 100 will stand almost perpendicular to the ground, making it possible to begin stable rotary penetration.

[0044] Second Embodiment

[0045] 4 is a schematic bottom view of a steel pipe pile tip member 10 according to a second embodiment. The difference from the first embodiment is the size of the tip reinforcing plate 16 and the presence or absence of a spacer 20.

[0046] Unlike the first embodiment, the tip reinforcement plate 16 of the steel pipe pile tip member 10 according to the second embodiment does not cover the center of the closure plate 12, but rather covers the range from approximately the middle of the radius of the closure plate 12 to the end of the expansion section 14. Therefore, unlike the first embodiment, there is no place where a spacer 20 can be installed, and so no spacer 20 is attached.

[0047] In this second embodiment, the tip reinforcing plate 16 is made from scrap material generated during the manufacturing of the flared section 14. Typically, the flared section 14 is manufactured by cutting out a square steel plate. The scrap material generated during this process is reused as the tip reinforcing plate 16, so the tip reinforcing plate 16 is smaller in size than in the first embodiment. Therefore, the longest side of the tip reinforcing plate 16, that is, the length of the side that contacts the closure plate 12 and the flared portion 14, is at most about 85% of the radius of the flared portion 14.

[0048] However, as a result of the rotational penetration test of the steel pipe pile 100, the steel pipe pile tip member 10 according to the second embodiment also exhibited good durability and penetration performance similar to that of the first embodiment.

[0049] Figure 5 is a schematic diagram of the tip reinforcement plate 16 as seen from above and from the side. As shown in this figure, the tip reinforcement plate 16 is triangular, and the apex of the isosceles triangle cuts into the ground while destroying gravel and rocks in the ground as it rotates and penetrates the ground surface. This allows the steel pipe pile 100 equipped with the steel pipe pile tip member 10 to exhibit high rotational penetration performance.

[0050] The preferred embodiments of the present invention have been described above with reference to the accompanying drawings.

[0051] It is clear that a person skilled in the art can think of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. [Industrial Applicability]

[0052] The present invention can be used as a steel pipe pile tip member used at the tip portion of a steel pipe pile. [Explanation of symbols]

[0053] 10: Steel pipe pile tip member, 12: Closure plate, 14: Spreading portion, 16: Tip reinforcing plate, 18: Auxiliary excavation member, 20: Spacer, 100: Steel pipe pile

Claims

1. A steel pipe pile tip member attached to the tip of a cylindrical steel pipe pile that rotates and penetrates vertically into the ground, An expansion portion attached to the outside of the tip portion of the steel pipe pile; A closing plate attached to the tip opening of the steel pipe pile; A tip reinforcing plate attached to the tip of the expansion portion on the rotational penetration direction side of the steel pipe pile and having a triangular shape; It consists of A steel pipe pile tip member characterized in that the contact portion between the closing plate and the tip reinforcing plate is fixed by welding.

2. A steel pipe pile tip member as described in Claim 1, characterized in that the expansion portion and the blocking plate are connected at least at one point.

3. 3. The steel pipe pile tip member according to claim 1, wherein the tip reinforcing plate is installed at an angle of 7 to 20 degrees from the horizontal direction toward the penetration direction.

4. The steel pipe pile tip member according to claim 3, characterized in that the tip reinforcing plate is provided with a spacer between the tip reinforcing plate and the closing plate.

5. The steel pipe pile tip member described in claim 4, characterized in that the closing plate has an auxiliary excavation member, and the tip portion of the auxiliary excavation member is positioned at a position rotated approximately 180 degrees from the tip portion of the tip reinforcement plate around the closing plate.

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