Steel pipe pile driving tool, steel pipe pile with excavation wings, and method for driving steel pipe piles

Abstract

The present invention provides a steel pipe pile driving tool, a steel pipe pile with excavation wings, and a steel pipe pile driving method that minimize disturbance to the surrounding soil of the steel pipe shaft in a steel pipe pile, and minimize wear during excavation. [Solution] The driving tool 1 is a driving tool for driving a steel pipe pile 3 with drilling wings, which has drilling wings 32 on the tip side of the shaft steel pipe 31, into the ground 4. The driving tool 1 is insertable into and removes from the shaft steel pipe 31 and includes an insertion rotating part 11 that rotates inside the shaft steel pipe 31 when inserted, and a rotation transmission part 12 provided on the tip side of the insertion rotating part 11, which fits into the center of the drilling wings 32 and transmits the rotation of the insertion rotating part 11 to the drilling wings 32.

Description

Technical Field

[0001] The present invention relates to a steel pipe pile with excavation blades used for ground improvement, a driving tool for driving the steel pipe pile into the ground, and a method for driving the steel pipe pile.

Background Art

[0002] Conventionally, in the improvement construction of soft ground, a steel pipe pile with excavation blades (fins) has been developed, which can facilitate the penetration of the steel pipe pile by applying rotation to the steel pipe pile and can increase the bearing capacity of the steel pipe pile in the ground after construction.

[0003] Furthermore, Patent Document 1 discloses a method of rotatively pressing a casing into the ground, the casing including a first fin (excavation blade) fixed to the casing body, a second fin (excavation blade) detachably engaged with the casing body, and a hook mechanism for engaging the second fin with the casing body. A steel pipe pile inserted into the casing body is inserted into the second fin, the hook mechanism is released to release the second fin from the casing body, the casing body is pulled out while leaving the second fin and the steel pipe pile, and the space between the casing body and the steel pipe pile is backfilled with earth and sand.

[0004] In addition, Patent Document 2 discloses an excavation rod including a rod body, an excavation head (excavation blade), and a connecting rod vertically connected between the rod body and the excavation head. The excavation head has a first shaft portion and a horizontal protruding portion provided below the upper end of the first shaft portion and protruding radially outward from the outer peripheral surface of the first shaft portion. The connecting rod has a cylindrical second shaft portion into which the first shaft portion can be inserted and a plate-shaped downward protruding portion extending vertically downward from a position radially outside the second shaft portion to a position below the horizontal position where the lower end of the second shaft portion is located.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, the conventional steel pipe pile installation method and excavation head described above involve penetrating the ground with a casing (guide rod) that has an inner diameter larger than the outer diameter of the steel pipe shaft. This significantly disturbs the ground around the steel pipe shaft and removes soil, potentially making buildings more susceptible to shaking from earthquakes or traffic vibrations compared to ground improved using general steel pipe pile construction methods. Furthermore, although the casing is equipped with wings (second fins) to compact the disturbed ground and fill in the removed soil, it is uncertain whether the greatly disturbed ground will be sufficiently compacted and whether soil will be filled along the entire length of the steel pipe shaft. In addition, since the casing excavates the ground when the steel pipe shaft is driven, there is the drawback that the casing wears down with each excavation.

[0007] In view of the above circumstances, this invention aims to provide a driving tool, a steel pipe pile with excavation wings, and a method for driving steel pipe piles that are less likely to cause disturbance to the soil surrounding the shaft steel pipe of a steel pipe pile, and that are less likely to cause wear during excavation. [Means for solving the problem]

[0008] The steel pipe pile driving tool according to this invention is a driving tool for driving a steel pipe pile with drilling wings, which has drilling wings on the tip side of the shaft steel pipe, into the ground in order to solve the above problems, and is characterized by comprising: an insertion rotating part that can be inserted into and removed from the shaft steel pipe and rotates inside the shaft steel pipe when inserted; and a rotation transmission part provided on the tip side of the insertion rotating part, which fits into the center of the drilling wings and transmits the rotation of the insertion rotating part to the drilling wings.

[0009] With the above configuration of the driving tool, the insertable rotating part is inserted into the shaft steel pipe, and the steel pipe pile with excavation wings is rotated to excavate the ground. Therefore, the ground around the shaft steel pipe is not significantly disturbed, and no soil is removed. Consequently, there is no need to compact the disturbed ground or fill in the removed soil. Also, since it is the steel pipe pile that contacts the ground, the driving tool does not wear down with each excavation. Furthermore, the rotational force from the rotating lifting part of the driving machine is transmitted from the insertable rotating part of the driving tool to the excavation wings, rather than from the shaft steel pipe to the excavation wings, so the shaft steel pipe is less likely to experience torsional stress. For this reason, it becomes easy to reduce the size of the shaft steel pipe (smaller diameter and thinner) to suppress ground improvement costs.

[0010] The rotation transmission unit may have a hook portion that fits under the engaging portion formed in the center of the drilling blade and hooks onto the engaging portion. This allows the steel pipe pile with the drilling blade to be hooked onto the driving tool and supported, making it easier to move the steel pipe pile to the drilling site and perform other operations.

[0011] The above-mentioned insertable rotating part may have a length such that its rear end protrudes from the shaft steel pipe. This makes it easier to attach the rear end of the insertable rotating part to the rotating lifting part of the concrete casting machine.

[0012] Furthermore, the steel pipe pile of this invention is a steel pipe pile with drilling wings, which are provided on the tip side of the shaft steel pipe, and is characterized in that the center of the drilling wings has a receiving fitting portion into which the rotation transmission portion of the driving tool is fitted.

[0013] In the case of the steel pipe pile described above, the rotation of the insertion rotating part of the driving tool is received by the receiving fitting part from the rotation transmission part, thereby rotating the excavation blade. Compared to a structure in which the excavation blade is rotated by the shaft steel pipe, the torsional load on the shaft steel pipe can be reduced, making it easier to reduce the size of the shaft steel pipe.

[0014] In the above-described steel pipe pile, the shaft steel pipe and the excavation blade may be fixed to each other by welding. This allows the shaft steel pipe to be driven into the ground together with the excavation blade by the thrust force in the soil caused by the rotation of the excavation blade.

[0015] Furthermore, the method for driving steel pipe piles according to this invention is characterized by including the steps of: inserting the insertion rotating part of the driving tool into the shaft steel pipe of a steel pipe pile with drilling wings, which is equipped with drilling wings on the tip side of the shaft steel pipe, and fitting the rotation transmission part into the center of the drilling wings; attaching the rear end of the insertion rotating part to the rotating lifting part of the driving machine; lowering the rotating lifting part to drive the steel pipe pile with drilling wings into the ground while rotating it; and removing the driving tool from the shaft steel pipe.

[0016] According to the above method, the ground around the shaft steel pipe is not significantly disturbed or soil is not removed, and therefore there is no need to compact the disturbed ground or fill in the removed soil. Also, since it is a steel pipe pile that is in contact with the ground, the driving tool does not wear down with each excavation. Furthermore, the rotational force in the rotating and lifting part of the driving machine is not transmitted from the shaft steel pipe to the excavation blade, but rather from the insertion rotating part to the excavation blade, so torsional stress is less likely to occur on the shaft steel pipe. For this reason, it becomes easier to reduce the size of the shaft steel pipe. [Effects of the Invention]

[0017] With this invention, disturbance to the soil surrounding the steel shaft of the steel pipe pile is less likely to occur, and wear during excavation of the driving tool is less likely to occur. Furthermore, since torsional stress is less likely to occur on the steel shaft, it is possible to reduce the size of the steel shaft and thus reduce ground improvement costs, among other effects. [Brief explanation of the drawing]

[0018] [Figure 1] This is an explanatory diagram showing the driving tool, steel pipe pile, and driving method of an embodiment. [Figure 2] Figure 1 is a partially fractured explanatory diagram showing the driving tool and steel pipe pile with excavation wings in a perspective view. [Figure 3] It is an explanatory view showing an enlarged part of FIG. 2. [Figure 4] It is an explanatory view showing a modified example of the placing tool and the steel pipe pile with excavation wings of the embodiment. [Figure 5] It is an explanatory view showing a modified example of the placing tool and the steel pipe pile with excavation wings of the embodiment. [Figure 6] It is an explanatory view showing a modified example of the placing tool and the steel pipe pile with excavation wings of the embodiment.

Mode for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. As shown in FIG. 1, the placing tool 1 of the embodiment includes an insertion rotation part 11 and a rotation transmission part 12, and is attached to the rotation lifting part 21 of the placing machine 2 and is used to penetrate the steel pipe pile 3 with excavation wings into the ground 4. The steel pipe pile 3 with excavation wings has, for example, spiral excavation wings 32 on the tip side (end part in the ground) of the shaft steel pipe 31 made of round steel pipe. The excavation wings 32 become support wings that support the shaft steel pipe 31 in the ground after the penetration of the steel pipe pile 3.

[0020] As shown in FIGS. 2 and 3, the insertion rotation part 11 of the placing tool 1 can be inserted into and removed from the shaft steel pipe 31, and is rotated around the axis of the shaft steel pipe 31 inside the shaft steel pipe 31 in the inserted state. This rotation is imparted by the rotation lifting part 21 of the placing machine 2. The insertion rotation part 11 is made of a relatively thick-walled round steel pipe material having an outer diameter that is, for example, about 5 mm to 40 mm smaller than the inner diameter of the shaft steel pipe 31. Also, in this embodiment, the rear end side of the insertion rotation part 11 has a length that protrudes from the shaft steel pipe 31, and the rear end side is held by the rotation lifting part 21. Note that the insertion rotation part 11 is not limited to round steel pipe material, and may be made of square steel pipe material or bar steel material.

[0021] The rotation transmission unit 12 is provided on the tip side of the insertion rotating unit 11 and fits into the center of the drilling blade 32, transmitting the rotation of the insertion rotating unit 11 to the drilling blade 32. The rotation transmission unit 12 only needs to have a structure that can transmit rotational torque to the drilling blade 32, and is not limited to the structure exemplified below.

[0022] In this embodiment, the rotation transmission unit 12 fits into a circular concave receiving fitting portion 32a formed in the center of the drilling blade 32. The rotation transmission unit 12 also includes a pair of hook portions 12a that each fit under a pair of opposing engaging portions 32b that protrude toward the center from the inner circumferential surface of the receiving fitting portion 32a and hook onto the drilling blade 32. When inserting the insertion rotation unit 11 into the shaft steel pipe 31, the driving tool 1 is lowered while avoiding contact between the pair of hook portions 12a and the pair of engaging portions 32b, and after the rotation transmission unit 12 enters the receiving fitting portion 32a, the driving tool 1 is rotated by approximately 90 degrees, allowing the pair of hook portions 12a to fit under the pair of engaging portions 32b.

[0023] Furthermore, in the steel pipe pile 3, the tip of the shaft steel pipe 31 is welded and fixed to the upper end of the peripheral wall of the receiving fitting portion 32a of the excavation blade 32, so that the shaft steel pipe 31 and the excavation blade 32 rotate together. The appearance of the steel pipe pile 3 may be the same as that of existing piles.

[0024] In the installation of the steel pipe pile 3 into the ground 4, as shown in Figure 1, the following steps are taken: inserting the insertion and rotating part 11 of the driving tool 1 into the shaft steel pipe 31 of the steel pipe pile 3 with excavating wings, and fitting the rotation transmission part 12 into the center (receiving fitting part 32a) of the excavating wing 32; attaching the rear end of the insertion and rotating part 11 to the rotating and lifting part 21 of the driving machine 2; lowering the rotating and lifting part 21 to drive the steel pipe pile 3 with excavating wings into the ground 4 while rotating it; and raising the rotating and lifting part 21 to remove the driving tool 1 from the shaft steel pipe 31. If it becomes necessary to remove the steel pipe pile 3 with excavating wings from the ground 4, the insertion and rotating part 11 can be rotated in the opposite direction to when it was driven in, thereby removing the steel pipe pile 3 with excavating wings from the ground 4. Furthermore, for this extraction, the driving tool 1 may be structured to include another hook portion facing the opposite direction to the hook portion 12a, or a driving tool specifically for extraction may be used that is equipped only with a hook portion facing the opposite direction to the hook portion 12a.

[0025] In this way, since the insertable rotating part 11 is inserted into the shaft steel pipe 31 and the steel pipe pile 3 with excavating blades is rotated to excavate the ground 4, the ground 4 around the shaft steel pipe 31 is not greatly disturbed or soil is removed, and therefore there is no need to compact the disturbed ground 4 or fill in the removed soil. Also, since it is the steel pipe pile 3 that is in contact with the ground 4, the driving tool 1 does not wear down with each excavation. Furthermore, the rotational force from the rotating lifting part 21 of the driving machine 2 is not transmitted from the shaft steel pipe 31 to the excavating blades 32, but rather from the insertable rotating part 11 of the driving tool 1 to the excavating blades 32, so torsional stress is less likely to occur on the shaft steel pipe 31. For this reason, it becomes easy to reduce the size of the shaft steel pipe 31 (smaller diameter and thinner thickness) to suppress ground improvement costs.

[0026] Furthermore, if the rotation transmission section 12 of the driving tool 1 is equipped with a hook section 12a, the steel pipe pile 3 with excavation wings can be hooked onto the driving tool 1 and supported, making it easier to move the steel pipe pile 3 to the excavation site and perform other operations.

[0027] Furthermore, if the rear end of the insertable rotating part 11 protrudes from the shaft steel pipe 31, it becomes easier to attach the rear end of the insertable rotating part 11 to the rotating lifting part 21 of the concrete casting machine 2. In the illustration, no special processing is shown on the rear end of the insertable rotating part 11, but as an example, a hexagonal prism part may protrude from the center of the rear end of the insertable rotating part 11, and a hexagonal hole may be formed in the rotating lifting part 21 into which the hexagonal prism part fits. Alternatively, if the rear end of the insertable rotating part 11 does not protrude from the shaft steel pipe 31, for example, a key may be formed to protrude within the central cavity of the insertable rotating part 11, and a protruding fitting body that protrudes so as to fit into the central cavity may be attached to the rotating lifting part 21, and a key groove may be formed in this protruding fitting body into which the key engages.

[0028] Furthermore, in the steel pipe pile with drilling wings 3, the drilling wings 32 have a receiving fitting portion 32a in the center into which the rotation transmission portion 12 of the driving tool 1 fits. The rotation of the insertion rotating portion 11 of the driving tool 1 is received by the receiving fitting portion 32a from the rotation transmission portion 12, thereby rotating the drilling wings 32. Compared to a structure in which the drilling wings 32 are rotated by a shaft steel pipe 31 whose rear end is gripped by a rotating lifting portion 21, the torsional load on the shaft steel pipe 31 is reduced, and the size of the shaft steel pipe 31 can be easily reduced.

[0029] Furthermore, if the shaft steel pipe 31 and the excavation blade 32 are fixed to each other by welding, the thrust force in the soil caused by the rotation of the excavation blade 32 can drive the shaft steel pipe 31 into the ground 4 together with the excavation blade 32. However, if a driving tool 1 having a downsized shaft steel pipe 31 is driven into the ground 4, and then a steel pipe of the same diameter and wall thickness as the shaft steel pipe 31 is added, the resulting lengthened shaft steel pipe 31 and the added steel pipe may not be able to withstand the torsional stress caused by friction with the surrounding soil due to their rotation. Therefore, when adding such steel pipes, it may be chosen not to downsize the shaft steel pipe 31. Alternatively, the shaft steel pipe 31 that is driven in first may not be downsized, and the shaft steel pipes that are connected later may be downsized.

[0030] Figure 4 shows a modified example of the driving tool 1 and the steel pipe pile 3 with drilling wings. In this modified example, the rotation transmission part 12 has a rectangular prism shape and fits into a rectangular recessed receiving fitting part 32a formed on the central cylindrical part of the drilling wing 32. In this rectangular prism shape and rectangular recessed fitting, the rotation of the insertion rotation part 11 can be received by the receiving fitting part 32a from the rotation transmission part 12 to rotate the drilling wing 32, but the rotation transmission part 12 cannot hook onto the drilling wing 32. However, even in this rectangular prism shape and rectangular recessed fitting, it is possible to provide a hook function by giving the fitting form the same engagement structure as shown in Figure 3.

[0031] Figure 5 shows another modified example of the driving tool 1 and the steel pipe pile 3 with drilling wings. In this modified example, the rotation transmission part 12 has a groove that extends in the diametrical direction, and this groove fits into a partition-shaped receiving fitting part 32a that crosses the circular concave receiving fitting part 32a of the drilling wing 32. In this groove-shaped and partition-shaped fitting, the rotation of the insertion rotation part 11 can be received by the receiving fitting part 32a from the rotation transmission part 12 to rotate the drilling wing 32, but the rotation transmission part 12 cannot hook the drilling wing 32. However, even in this groove-shaped and partition-shaped fitting, it is possible to provide a hook function by giving the fitting form the same engagement structure as shown in Figure 3.

[0032] The modifications shown in Figures 4 and 5 are not the only ones; as shown in Figure 6, the rotation transmission section 12 may have a fan-shaped notch, and the drilling blade 32 may have a fan-shaped convex portion corresponding to the notch within the circular concave receiving fitting portion 32a on the central side.

[0033] Although embodiments of this invention have been described above with reference to the drawings, this invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiments within the same scope as this invention, or within the equivalent scope. [Explanation of Symbols]

[0034] 1: Driving tool 2: Concrete pouring machine 3: Steel pipe pile with excavation wings 4: Ground 11: Insertion and rotation part 12: Rotation transmission section 12a: Hook part 21: Rotating and lifting section 31: Shaft steel pipe 32: Excavation blade 32a: Receiving and fitting part 32b: Engagement part

Claims

1. A driving tool for steel pipe piles with drilling wings, which are provided on the tip side of the shaft steel pipe, to be driven into the ground, comprising: an insertion rotating part that can be inserted into and removed from the shaft steel pipe and rotates inside the shaft steel pipe when inserted; and a rotation transmission part provided on the tip side of the insertion rotating part, which fits into the center of the drilling wings and transmits the rotation of the insertion rotating part to the drilling wings.

2. A steel pipe pile driving tool according to claim 1, wherein the rotation transmission part has a hook part that fits under the engaging part formed in the central part of the excavation blade and hooks onto the engaging part.

3. A steel pipe pile driving tool according to claim 1, characterized in that the insertion rotating part has a length such that the rear end of the insertion rotating part protrudes from the shaft steel pipe.

4. A steel pipe pile with drilling wings, comprising drilling wings on the tip side of the shaft steel pipe, characterized in that the center of the drilling wing has a receiving fitting portion into which the rotation transmission portion of the steel pipe pile driving tool described in any one of claims 1 to 3 is fitted.

5. A steel pipe pile with drilling wings according to claim 4, characterized in that the shaft steel pipe and the drilling wings are fixed to each other by welding.

6. A method for driving a steel pipe pile, comprising the steps of: inserting the insertion rotating part of the steel pipe pile driving tool described in any one of claims 1 to 3 into the shaft steel pipe of a steel pipe pile with drilling wings, which is provided on the tip side of the shaft steel pipe, and fitting the rotation transmission part into the center of the drilling wings; attaching the rear end of the insertion rotating part to the rotating lifting part of a driving machine; lowering the rotating lifting part to drive the steel pipe pile with drilling wings into the ground while rotating it; and removing the driving tool from the shaft steel pipe.

Images