JP7790399B2 - Rotary joint method for steel pipe pile with fluid supply pipe - Google Patents

Description

This relates to a rotary joining method for a steel pipe pile with a fluid supply pipe, which is rotary joined and arranged in the axial direction of the pile to supply fluid to the inner surface and/or tip of the pile.

Welded joints are generally used to join steel pipe piles, but in cases where fire cannot be used or where joining time needs to be shortened, mechanical joints are increasingly being used at the joints, and one such mechanical joint is the threaded joint (see Patent Document 1).

In addition, when driving steel pipe piles, in order to improve workability, a fluid supply pipe is installed along the inner surface of the steel pipe pile from the top to the bottom, and water, drilling fluid, air, etc. are supplied to the fluid supply pipe and discharged from the bottom end of the pile (see Patent Documents 2 and 3).

The fluid supply pipe is usually attached to the inner surface of the steel pipe in advance at a factory or on-site (fixed with a fixing band, welding, etc.) (Patent Document 3: Fixing of the pipe on the lower pile side)
If the steel pipe pile has a joint (vertical joint welded on site or horizontal joint welded at the storage site), after the upper pile is positioned, the fluid supply pipe at the joint position is connected (linked) via a component such as a socket or joint pipe, and then the upper pile and lower pile are welded together.

Patent No. 6575553 Patent No. 4242251 Japanese Patent Application Publication No. 2018-123670 Patent No. 6354911

When installing a fluid supply pipe on the inner surface of a steel pipe pile during joint installation, the fluid supply pipe may not be able to withstand the soil pressure of the soil flowing into the steel pipe during installation and may be damaged. Therefore, the fluid supply pipe must be fixed to the inner surface of the steel pipe pile before installation.
Furthermore, when joining an upper pile to a lower pile that has already been driven in, the fluid supply pipe is inserted into the upper pile, and before joining the lower and upper piles, the upper end of the fluid supply pipe on the lower pile side is joined to the lower end of the fluid supply pipe on the upper pile side, and then the lower and upper piles are joined.

However, when joining the upper and lower piles with a threaded joint, if the lower end of the fluid supply pipe on the upper pile side is joined to the upper end of the fluid supply pipe on the lower pile side and the fluid supply pipe is fixed to the upper pile along its entire length, rotating the upper pile will twist the fluid supply pipe by the amount of joint rotation, damaging the fluid supply pipe, and this creates a problem: the upper pile cannot be rotatably joined to the lower pile.

The above problem is not limited to joints that use threaded joints as the rotary joining mechanism. Similar problems occur with joints, such as those disclosed in Patent Document 4, in which the inner joint pipe is inserted into the outer joint pipe to the fully inserted position, and then the outer or inner joint pipe is rotated a predetermined angle when the insertion is complete, thereby engaging the two and forming a rotary joining.

The present invention was made to solve these problems, and aims to provide a rotary joining method for a steel pipe pile with a fluid supply pipe that enables the joining of the fluid supply pipe and the upper and lower piles without damaging the fluid supply pipe.

When joining steel pipe piles with fluid supply pipes, the conventional procedure involves joining the fluid supply pipe on the upper pile side to the fluid supply pipe on the lower pile side, and then joining the upper and lower piles together. This procedure creates problems with piles that are rotary joined. Therefore, we conducted extensive research into connecting the fluid supply pipe after rotary joining the upper and lower piles, and arrived at the present invention, which specifically features the following configuration.

(1) The rotary joining method for a steel pipe pile with a fluid supply pipe according to the present invention is a rotary joining method for a steel pipe pile with a fluid supply pipe, which is provided with a fluid supply pipe arranged in the axial direction of the pile and supplies a fluid to the inner surface of the pile and/or the tip of the pile, and a joint having an anti-rotation pin hole into which an anti-rotation pin is inserted,
a pile joining process in which a lower pile having a lower pile-side fluid supply pipe disposed on the inner surface of the pile and driven into the ground, and an upper pile having an upper pile-side fluid supply pipe disposed on the inner surface of the pile and a connecting pipe provided at the lower end of the upper pile-side fluid supply pipe so as to be movable downward, are rotationally joined together so that the axes of the lower pile-side fluid supply pipe and the upper pile-side fluid supply pipe are aligned;
The method is characterized by comprising a fluid supply pipe connecting step of accessing the connecting pipe from the anti-rotation pin hole, lowering the connecting pipe, and connecting the upper pile side fluid supply pipe and the lower pile side fluid supply pipe via the connecting pipe.

(2) Furthermore, in the device described in (1) above, the connecting pipe has a protrusion, and in the fluid supply pipe connecting step, the protrusion is accessed and pressed down.

(3) Furthermore, in the device described in (2) above, the protrusion has a protruding portion that protrudes in the circumferential direction of the pile, and is characterized in that it engages with the anti-rotation pin inserted into the anti-rotation pin hole, thereby restricting the movement of the connecting pipe.

(4) Furthermore, in the device described in (2) above, the protrusion has a U-shape into which the anti-rotation pin can be inserted, and inserting the anti-rotation pin restricts the movement of the connecting pipe up and down and in the circumferential direction of the pile.

(5) Furthermore, in the above (1), the lower pile side fluid supply pipe and the upper pile side fluid supply pipe are each arranged in multiple lines, and the connecting pipe is characterized by comprising multiple vertical pipes and connecting members connecting the multiple vertical pipes.

In this invention, after the steel pipe piles are rotary joined, the fluid supply pipe on the upper pile side and the fluid supply pipe on the lower pile side are connected via a connecting pipe, so the rotary joined steel pipe piles can be joined without damaging the fluid supply pipes. This allows threaded joints to be used on site regardless of the pile construction method, reducing the burden of on-site welding work and shortening construction times.

1 is an explanatory diagram of a rotary joining method for a steel pipe pile with a fluid supply pipe according to Embodiment 1. FIG. 1 is an explanatory diagram of a rotary joining method for a steel pipe pile with a fluid supply pipe according to embodiment 1, showing cross-sectional views of the joint ((a-1), (b-1), (c)) and arrow A-A views ((a-2), (b-2)). FIG. 2 is a detailed explanatory diagram of a connecting pipe according to the first embodiment. 2 is a cross-sectional view taken along the line BB in FIG. 1, illustrating the arrangement of connecting pipes. FIG. FIG. 4 is a diagram schematically illustrating the vicinity of a threaded joint with a fluid supply pipe connected thereto. FIG. 10 is a detailed explanatory view of a state in which a fluid supply pipe is connected. FIG. 10 is an explanatory diagram of another aspect of the first embodiment. FIG. 10 is a detailed explanatory diagram of a connecting pipe according to a second embodiment. FIG. 10 is an explanatory diagram illustrating the arrangement of connecting pipes according to the second embodiment. FIG. 10 is a diagram schematically illustrating the vicinity of a threaded joint in a state where a fluid supply pipe is connected in a second embodiment.

[First Embodiment]
In this embodiment, a threaded joint 1 having an anti-rotation pin hole 7 (see Figure 2) at the end of the pile is used as an example of a mechanism for rotary joining piles, and will be described based on Figures 1 to 6.
Furthermore, the fluid supply pipes 5 disposed on the inner surface of the steel pipe pile 3 with a fluid supply pipe attached thereto are installed in multiple numbers, typically four. The four fluid supply pipes 5 may be arranged one by one at equal intervals in the circumferential direction (at every 90 degrees) (see FIG. 4), or two fluid supply pipes 5 are arranged closely together as a set, with the two sets being arranged at equal intervals in the circumferential direction (at every 180 degrees) (see FIG. 9). In this example, the case where the fluid supply pipes are arranged one by one at equal intervals in the circumferential direction will be described.

In this embodiment, the rotary joining method for a steel pipe pile 3 with a fluid supply pipe is a rotary joining method for a steel pipe pile 3 with a fluid supply pipe, as shown in Figures 1 and 2, which is provided with a fluid supply pipe 5 arranged in the axial direction of the pile to supply fluid to the inner surface of the pile and/or the tip of the pile, and a joint 1 having an anti-rotation pin hole 7 (see Figure 2) into which an anti-rotation pin 18 is inserted.
The method also includes a pile joining process (see Figures 1(a)(b)(c)) for joining the lower pile 3b and the upper pile 3a that have been driven into the ground, and a fluid supply pipe connecting process (see Figures 1(d) and 2) for connecting the upper pile side fluid supply pipe 5a and the lower pile side fluid connecting pipe 5b via a connecting pipe 9.
Each step will be described in detail below.

<Pile joining process>
First, the structure of the lower pile 3b and the upper pile 3a used in the pile joining process will be described.
《Lower stake》
As shown in Figures 1 and 2, the lower pile 3b is driven into the ground, and the lower pile side fluid connecting pipe 5b is arranged so that it passes in the axial direction of the pile near the position of the anti-rotation pin hole 7 on the inner surface of the pile, and is fixed by a fixing member 11 (the same applies to the upper pile 3a).
As shown in FIG. 2, the upper end of the lower pile-side fluid connecting pipe 5b is bent toward the inside of the pile so as to avoid the threaded joint 1.
An O-ring 13 is provided on the inner surface of the upper end of the lower pile-side fluid connecting pipe 5b, at the location where the lower part of the connecting pipe 9 is inserted. By providing the O-ring 13, the inserted connecting pipe 9 is held in a tightened state, so that the supplied fluid can be stopped from leaking and can withstand high-pressure water supply.

《Upper stake》
The upper pile 3a has an upper pile-side fluid supply pipe 5a arranged on the inner surface of the pile near the position of the anti-rotation pin hole 7 (see Figure 5). The lower end of the upper pile-side fluid supply pipe 5a, like the upper end of the lower pile-side fluid connecting pipe 5b, is bent toward the inside of the pile to avoid the threaded joint 1 (see Figure 2).
In addition, an O-ring 13 is provided on the inner surface of the lower end of the upper pile side fluid supply pipe 5a, and the upper part of the connecting pipe 9 is inserted into the O-ring 13, thereby holding the connecting pipe 9 so that it can move downward.

The connecting pipe 9 has a smaller diameter than the fluid supply pipe 5, and as shown in FIG. 3, has a rod-shaped protrusion 15 at the bottom.
The upper and lower end surfaces of the connecting pipe 9 are provided with tapered surfaces 17 (see FIG. 3), which make it easier to insert the connecting pipe 9 into the fluid supply pipe 5 .

With the connecting pipe 9 attached to the upper pile-side fluid supply pipe 5a, the protrusion 15 is oriented so as to protrude in the circumferential direction of the pile as shown in Figure 4. At this time, the protrusion 15 is visible from the anti-rotation pin hole 7 as shown in Figure 2 (a-1).
The shape of the protrusion 15 is not particularly limited, and it may be any shape that can be pushed down with a crowbar or the like in the step of connecting the fluid supply pipe 5. In the case of a rod-shaped protrusion 15, it is preferable to provide a barb at the end of the rod, for example, in a J-shape, so that the connecting pipe 9 can be pushed down without rotating.

It is preferable to install a connecting pipe guard near the connecting pipe 9 at the location where the connecting pipe 9 is installed to prevent the connecting pipe 9 from being damaged by soil or sand passing through the inside of the pile during pile driving. The connecting pipe guard can be made of, for example, an L-shaped steel beam or round steel beam, and should be installed before the pile is driven.

When joining the upper pile 3a to the lower pile 3b as described above, the upper pile 3a is positioned in alignment with the axis of the lower pile 3b (Figure 1(a)), the upper pile 3a is lowered to abut against the lower pile 3b (see Figure 1(b)), and then rotated to join the upper pile 3a and the lower pile 3b.
When the piles are completely joined, as shown in Figures 1(c) and 2(a), the axes of the upper pile side fluid supply pipe 5a and the lower pile side fluid connecting pipe 5b are approximately aligned, and the connecting pipe 9 held by the upper pile side fluid supply pipe 5a can be inserted into the lower pile side fluid connecting pipe 5b.

Furthermore, as shown in Figure 2(a), when the pile connection is complete, the anti-rotation pin holes 7 of the inner and outer threaded joints 1 are in a connected state, and the connecting pipe 9 is accessible from the anti-rotation pin hole 7.

<Fluid supply pipe connecting step>
The fluid supply pipe connecting step is a step of connecting the upper pile side fluid supply pipe 5a and the lower pile side fluid connecting pipe 5b via the connecting pipe 9.
Specifically, a crowbar or the like is inserted through the anti-rotation pin hole 7 to access the protrusion 15 of the connecting pipe 9, and the protrusion 15 is pushed down to move the connecting pipe 9 downward, and the lower end of the connecting pipe 9 is inserted into the upper end of the lower pile side fluid connecting pipe 5b (see Figure 1 (d)).
The tool used to push down the connecting pipe 9 is not particularly limited, and any tool or member that can be inserted through the anti-rotation pin hole 7 and that can be used to perform the pushing operation can be used instead.

The relative positions of the threaded joint 1, anti-rotation pin hole 7, and connecting pipe 9 at this time are shown in Figures 2(b) and 5. Note that while Figure 2 shows an example with one protrusion 15, Figure 5 shows an example with two protrusions 15. When two protrusions 15 are provided, as shown in Figure 5, the vertical spacing between the protrusions 15 is larger than the diameter of the anti-rotation pin hole 7 so as not to interfere with the insertion of the anti-rotation pin 18.

After insertion, the anti-rotation pin 18 is screwed in. As shown in Figure 2(c), the length of this anti-rotation pin 18 is preferably set so that it extends further back than the position of the connecting pipe 9. This allows the anti-rotation pin 18 to abut against the protrusion 15, preventing the connecting pipe 9 from moving upward. In other words, the anti-rotation pin 18 has the function of preventing the connecting pipe 9 from moving in addition to its original function of preventing rotation of the threaded joint 1.
Furthermore, as shown in FIG. 5, when there are two projections 15, the upward and downward movement of the connecting pipe 9 is restricted by the rotation preventing pin 18.

Figure 6 is a detailed diagram of the upper pile-side fluid supply pipe 5a and the lower pile-side fluid connecting pipe 5b connected via the connecting pipe 9. In this example, as shown in Figure 6, a socket member 19 is welded to the upper end of the lower pile-side fluid connecting pipe 5b and the lower end of the upper pile-side fluid supply pipe 5a. The tip opening of the socket member 19 is provided with an inclined surface 21 that slopes toward the inner diameter, which, together with the tapered surface 17 of the connecting pipe 9, facilitates smooth insertion of the connecting pipe 9 into the upper pile-side fluid supply pipe 5a and the lower pile-side fluid connecting pipe 5b.

As described above, according to this embodiment, the fluid supply pipe 5 can be connected after the upper pile 3a has been rotationally joined to the lower pile 3b, allowing for rotational joining without damaging the fluid supply pipe 5. This makes it possible to join steel pipe piles equipped with fluid supply pipes 5 using threaded joints 1, reducing the burden of on-site welding work and shortening construction time.

In the above description, the protrusions 15 provided on the connecting pipe 9 were rod-shaped, but as shown in Figure 7, they can also be U-shaped. When a U-shaped protrusion 15 is provided, an anti-rotation pin 18 can be inserted into the opening of the U to restrict vertical and circumferential movement of the connecting pipe 9.

[Embodiment 2]
In embodiment 1, multiple fluid supply pipes 5 arranged on the inner surface of the steel pipe pile are arranged evenly in the circumferential direction, one by one. However, in the rotary joining method for a steel pipe pile 3 with a fluid supply pipe according to embodiment 2, a case will be described in which two fluid supply pipes 5 are arranged close to each other to form a set, and the two sets are arranged evenly in the circumferential direction.

As shown in FIG. 8, the connecting pipe 23 used in this embodiment comprises two vertical pipes 23a and two connecting members 23b (corresponding to the protrusions 15 of the present invention) connecting the two vertical pipes 23a.
In this case, the arrangement on the inner surface of the steel pipe pile is such that vertical pipes 23a are lined up in the circumferential direction, and these vertical pipes 23a are connected by connecting members 23b, as shown in FIG.

The process in this embodiment includes a pile joining process and a fluid supply pipe connecting process, similar to the first embodiment, and the work in each process is also similar to the first embodiment.
FIG. 10 is a schematic diagram showing the state in which the upper pile side fluid supply pipe 5a and the lower pile side fluid connecting pipe 5b are connected via the connecting pipe 23 in this embodiment.
In this state, as shown in Figure 10, the anti-rotation pin hole 7 is located between the upper and lower connecting members 23b, and by inserting the anti-rotation pin 18 into the anti-rotation pin hole 7, the connecting member 23b engages with the anti-rotation pin 18, thereby restricting the up and down movement of the connecting pipe 23.

In this second embodiment, as in the first embodiment, the fluid supply pipe 5 can be connected after the upper pile 3a is rotationally joined to the lower pile 3b, so that rotational joining is possible without damaging the fluid supply pipe 5.
The number of connecting members 23b in the second embodiment is not limited to two, but may be one.
Furthermore, in the above example, two fluid supply pipes 5 are arranged side by side, but the number of fluid supply pipes 5 arranged side by side is not limited to two and may be three or more, and in this case, a connecting member may be provided in the same way as in the case of two fluid supply pipes.

In the above explanation, the connecting pipe 23 has a protrusion 15, but even if the connecting pipe 23 does not have a protrusion 15, it is possible to access the connecting pipe 23 through the anti-rotation pin hole 7 and move the connecting pipe 23 downward using a tool that can grip the connecting pipe 23.

Furthermore, while the above description uses a threaded joint 1 as the rotary joining mechanism, the present invention is not limited to this. For example, the present invention can be similarly applied to joints such as those disclosed in Patent Document 4, in which the inner joint pipe is inserted into the outer joint pipe to the fully inserted position, and then the outer joint pipe or the inner joint pipe is rotated a predetermined angle when the insertion is complete, thereby engaging the two and forming a rotary joint.

The present invention is applicable to steel pipe piles with diameters of approximately 300mm to 2000mm, but its effectiveness has been confirmed with a typical steel pipe pile with a diameter of 1200mm.
Specifically, as an example of the present invention, a steel pipe pile with a threaded joint, φ1200 × t22 mm, L (top 3,000 mm, middle 2 3,000 mm, middle 1 3,000 mm, bottom 3,500 mm) was used, and after the pile was joined using the rotary joining method of the present invention for a steel pipe pile with a fluid supply pipe 3, the fluid supply pipe 5 was connected, and the pile was driven while supplying water.
It was confirmed that both the joining work of the fluid supply pipe 5 and the driving of piles while supplying water could be carried out smoothly.

DESCRIPTION OF SYMBOLS 1 Threaded joint 3 Steel pipe pile with fluid supply pipe 3a Upper pile 3b Lower pile 5 Fluid supply pipe 5a Upper pile side fluid supply pipe 5b Lower pile side fluid supply pipe 7 Rotation prevention pin hole 9 Connecting pipe (Embodiment 1)
11: Fixing member 13: O-ring 15: Protrusion 17: Tapered surface 18: Anti-rotation pin 19: Socket member 21: Inclined surface 23: Connecting pipe (Embodiment 2)
23a Vertical pipe 23b Connecting member

Claims (5)

A rotary joining method for a steel pipe pile with a fluid supply pipe, comprising: a fluid supply pipe arranged in the pile axial direction to supply a fluid to the inner surface of the pile and/or the tip of the pile; and a joint having an anti-rotation pin hole into which an anti-rotation pin is inserted.
a pile joining process in which a lower pile having a lower pile-side fluid supply pipe disposed on the inner surface of the pile and driven into the ground, and an upper pile having an upper pile-side fluid supply pipe disposed on the inner surface of the pile and a connecting pipe provided at the lower end of the upper pile-side fluid supply pipe so as to be movable downward, are rotationally joined together so that the axes of the lower pile-side fluid supply pipe and the upper pile-side fluid supply pipe are aligned;
A rotary joining method for a steel pipe pile with a fluid supply pipe, characterized by comprising a fluid supply pipe connecting process for accessing the connecting pipe through the anti-rotation pin hole, moving the connecting pipe downward, and connecting the upper pile side fluid supply pipe and the lower pile side fluid supply pipe via the connecting pipe. The rotary joining method for a steel pipe pile with a fluid supply pipe according to claim 1, characterized in that the connecting pipe has a protrusion, and in the fluid supply pipe connecting step, the protrusion is accessed and pushed down. The rotary joining method for a steel pipe pile with a fluid supply pipe described in claim 2, characterized in that the protrusion has a protruding portion that protrudes circumferentially around the pile and engages with the anti-rotation pin inserted into the anti-rotation pin hole to restrict movement of the connecting pipe. The rotary joining method for a steel pipe pile with a fluid supply pipe described in claim 2, characterized in that the protrusion has a U-shape into which the anti-rotation pin can be inserted, and inserting the anti-rotation pin restricts movement of the connecting pipe up and down and in the circumferential direction of the pile. A rotary joining method for a steel pipe pile with a fluid supply pipe as described in claim 1, characterized in that the lower pile side fluid supply pipe and the upper pile side fluid supply pipe are each arranged in multiple lines, and the connecting pipe comprises multiple vertical pipes and connecting members connecting the multiple vertical pipes.