JP7729792B2 - Steel pipe pile connection structure, steel pipe pile foundation, and steel pipe pile connection method - Google Patents

Description

The present invention relates to a steel pipe pile connection structure, a steel pipe pile foundation, and a steel pipe pile connection method.

The construction method for steel pipe piles is selected depending on the condition of the ground, but one method improves workability by combining rotary press-in with the injection of high-pressure water from the tip. Meanwhile, when piles are long, multiple piles are connected axially and driven into the piles. However, when high-pressure water injection is also used as described above, it becomes necessary to connect water pipes for the high-pressure water at the same time. In such cases, as described in Patent Documents 1 and 2, for example, one method involves connecting water pipes near the center of the cross section of the pile body. However, when considering the resistance of soil (blocking soil) flowing into the interior from the tip of the steel pipe pile, it is more advantageous to place the water pipes along the inner surface of the pile body.

Meanwhile, Patent Documents 3 and 4 describe a connection method using an inner fitting member and an outer fitting member joined to the axial ends of steel pipe piles. With this method, when the inner fitting member is rotated while fitted inside the outer fitting member, multiple protrusions formed on the outside of the inner fitting member and the inside of the outer fitting member, each sandwiching a gap in the circumferential direction, engage with each other, connecting the steel pipe piles. This type of connection structure has the advantages of being easier to work with than the conventional method of welding steel pipe piles together, and ensuring sufficient bending rigidity.

Japanese Patent Application Laid-Open No. 2005-200910 Japanese Patent Application Publication No. 09-264018 JP 2016-29250 A JP 2015-143466 A

However, when connecting steel pipe piles in which high-pressure water piping is arranged along the inner surface of the pile body using the above-mentioned connection method, the outer fitting member and the inner fitting member fitted inside the outer fitting member at the connection part create a stepped part that protrudes inside the pile body, making it difficult to stably connect the piping at the connection part. Therefore, in areas such as hard ground or ground with a lot of closed soil, the possibility of the piping connection part becoming disconnected has been taken into consideration, and the above-mentioned fitting connection method has not been applied in some cases.

The present invention therefore aims to provide a steel pipe pile connection structure, steel pipe pile foundation, and steel pipe pile connection method that can stably connect piping arranged along the inner surface of the steel pipe pile at a connection section that connects steel pipe piles axially using an inner fitting member and an outer fitting member.

[1] A connection structure for a steel pipe pile that connects first and second pile bodies in the axial direction, comprising: an inner fitting member joined to the axial end of the first pile body; an outer fitting member joined to the axial end of the second pile body; a first piping joined to the inner peripheral surface of the first pile body; and a second piping joined to the inner peripheral surface of the second pile body, wherein the inner fitting member includes a first fitting portion that fits into the inside of the outer fitting member and a through hole that connects the inside of the inner fitting member to the outside of the first fitting portion, and the outer fitting member includes a second fitting portion that fits into the outside of the inner fitting member, wherein the first piping and the second piping are connected through the through hole and a passage formed between the first fitting portion and the second fitting portion, and an opening is formed by a notch provided in the outer peripheral surface of at least one of the inner fitting member and the outer fitting member, circumferentially aligned with the through hole and the passage.
[2] A connection structure for steel pipe piles as described in [1], further comprising a connecting pipe connected to the first pipe and the second pipe and passing through the through hole and the passage.
[3] A connection structure of a steel pipe pile described in [1], in which an extension of the first pipe or the second pipe passes through the through hole and the passage.
[4] A steel pipe pile connection structure according to any one of [1] to [3], further comprising a cover body attached to the notch.
[5] A connection structure of a steel pipe pile described in any one of [1] to [4], wherein the passage is formed by a groove portion formed in at least one of the first fitting portion and the second fitting portion.
[6] A connection structure for a steel pipe pile described in any one of [1] to [5], wherein the first fitting portion includes a reduced diameter portion whose outer diameter gradually decreases toward the end opposite the first pile body in the axial direction, and a plurality of first protrusions formed on the outside of the reduced diameter portion with a gap portion therebetween in the circumferential direction, and the second fitting portion includes an expanded diameter portion whose inner diameter gradually increases toward the end opposite the second pile body in the axial direction, and a plurality of second protrusions formed on the inside of the expanded diameter portion with a gap portion therebetween in the circumferential direction, and the first protrusions and the second protrusions are configured to engage with each other when the inner fitting member is fitted inside the outer fitting member and rotated to a predetermined position.
[7] A connection structure for a steel pipe pile as described in [6], in which when the inner fitting member is rotated to the predetermined position while fitted inside the outer fitting member, the passage is formed in the portion where the gap portion of the first protrusion and the gap portion of the second protrusion in the circumferential direction are aligned.
[8] A connecting structure of a steel pipe pile described in [6], wherein a first protrusion notch is formed in the circumferential middle portion or end portion of at least one of the first protrusions, and a second protrusion notch is formed in the circumferential middle portion or end portion of at least one of the second protrusions, and when the inner fitting member is rotated to the predetermined position while fitted inside the outer fitting member, the positions of the first protrusion notch and the second protrusion notch in the circumferential direction are aligned, thereby forming the passage.
[9] A steel pipe pile foundation including at least one steel pipe pile connection structure according to any one of [1] to [8].
[10] A method for connecting steel pipe piles that connects first and second pile bodies in the axial direction, comprising the steps of: fitting a first fitting portion formed on an inner fitting member joined to the axial end of the first pile body into the inside of a second fitting portion formed on an outer fitting member joined to the axial end of the second pile body; and connecting a first pipe joined to the inner peripheral surface of the first pile body and a second pipe joined to the inner peripheral surface of the second pile body through an opening formed by a notch provided on the outer peripheral surface of at least one of the inner fitting member and the outer fitting member, wherein the first pipe and the second pipe are connected through a through hole that communicates the inside of the inner fitting member with the outside of the first fitting portion and a passage formed between the first fitting portion and the second fitting portion, and the notch and the opening are formed to be circumferentially aligned with the through hole and the passage.
[11] A method for connecting steel pipe piles as described in [10], further comprising the step of attaching a cover to the notch after connecting the first pipe and the second pipe.
[12] A method for connecting steel pipe piles as described in [10] or [11], wherein connecting pipes are used to connect the first pipe and the second pipe, the connecting pipes including a first connecting pipe connected to the first pipe and a second connecting pipe connected to the second pipe, and further including a step of connecting the first connecting pipe and the second connecting pipe to each other after the step of inserting the connecting pipes into the passage.
[13] A method for connecting steel pipe piles described in any one of [10] to [12], wherein a connecting pipe is used to connect the first pipe and the second pipe, and the process of connecting the first pipe and the second pipe includes a process of pulling out the connecting pipe that has been stored in advance inside at least one of the first pipe and the second pipe.
[14] The method for connecting steel pipe piles described in any one of [10] to [13], wherein the first fitting portion includes a reduced diameter portion whose outer diameter gradually decreases toward the end opposite the first pile body in the axial direction, and a plurality of first protrusions formed on the outside of the reduced diameter portion with a gap portion sandwiched between them in the circumferential direction, and the second fitting portion in the axial direction includes an expanded diameter portion whose inner diameter gradually increases toward the end opposite the second pile body, and a plurality of second protrusions formed on the inside of the expanded diameter portion with a gap portion sandwiched between them in the circumferential direction, and the step of fitting the first fitting portion into the inside of the second fitting portion includes a step of rotating the inner fitting member to a predetermined position with the inner fitting member fitted into the outer fitting member, thereby engaging the first protrusion and the second protrusion with each other.
[15] The step of connecting the first pipe and the second pipe includes a step of rotating the inner fitting member to the predetermined position while fitting it inside the outer fitting member, and then inserting a connecting pipe connected to the first pipe and the second pipe, or an extension of the first pipe or the second pipe, into the passage. [14] A method of connecting steel pipe piles described in [14].
[16] The method for connecting steel pipe piles described in [14], wherein the passage is formed in a position where it does not interfere with the first protrusion and the second protrusion before and after the inner fitting member is rotated to the predetermined position while fitted inside the outer fitting member, and the step of connecting the first pipe and the second pipe includes a step of placing a connecting pipe connected to the second pipe or an extension of the second pipe in the passage before rotating the inner fitting member while fitted inside the outer fitting member.

With the above configuration, the first and second pipes are connected through the through-hole formed in the inner fitting member and the passage formed between the mating portions of the inner and outer fitting members. The first and second pipes may be connected by a connecting pipe or by extensions of either or both of the first and second pipes, but no additional components are required to secure these connecting pipes or extensions. Furthermore, the connecting pipe or extension can be connected from the outside after the pile bodies are connected through openings formed by notches on the outer circumferential surfaces of at least one of the inner fitting member and the outer fitting member, enabling highly safe and stable construction. Therefore, with the above configuration, the first and second pipes arranged along the inner circumferential surface of the pile body in a steel pipe pile connection structure can be stably connected.

1 is a perspective view showing a state before connection of a steel pipe pile connection structure according to a first embodiment of the present invention. FIG. FIG. 2 is a cross-sectional view showing the state after the connection structure shown in FIG. 1 is connected. FIG. 3 is a partial cross-sectional view showing a state in which the connection of pipes is completed in the connection structure shown in FIGS. 1 and 2. 10A and 10B are diagrams illustrating an example of a connector that connects a pipe and a connecting pipe. 10A and 10B are diagrams illustrating an example of a connector that connects a pipe and a connecting pipe. 10A and 10B are diagrams illustrating an example of a connector for connecting connecting pipes to each other. 1 is a schematic diagram showing a first example of a method for connecting steel pipe piles according to a first embodiment of the present invention. FIG. FIG. 10 is a schematic diagram showing a second example of the method for connecting steel pipe piles according to the first embodiment of the present invention. 5A and 5B are schematic diagrams showing an example of a connection structure and a connection method for steel pipe piles according to a second embodiment of the present invention. 10A and 10B are schematic diagrams showing an example of a connection structure and a connection method for steel pipe piles according to a third embodiment of the present invention.

An exemplary embodiment of the present invention will be described in detail below with reference to the accompanying drawings. Note that in this specification and drawings, components having substantially the same functional configuration will be assigned the same reference numerals, and redundant explanations will be omitted.

1 is a perspective view showing a steel pipe pile connection structure according to a first embodiment of the present invention in a state before connection; FIG. 2 is a cross-sectional view showing the connection state of the connection structure shown in FIG. 1 after connection; and FIG. 3 is a partial cross-sectional view showing the connection structure shown in FIGS. 1 and 2 after piping has been connected. The steel pipe pile connection structure 1 according to this embodiment axially connects pile bodies 21 and 22. The connection structure 1 includes an inner fitting member 3, an outer fitting member 4, piping 51 and 52, a connecting pipe 6, and a cover body 7 (see FIG. 3 for the connecting pipe 6 and cover body 7). The pile bodies 21 and 22 are each made of steel pipes, and function as a single steel pipe pile when connected via the inner fitting member 3 and the outer fitting member 4. Steel pipe piles are driven into the ground using, for example, a rotary press-in method or a vibrohammer method, but the construction method is not particularly limited.

In the following description, the axial direction refers to the axial direction of the steel pipe pile formed by connecting the pile bodies 21, 22 via the inner fitting member 3 and outer fitting member 4, and is illustrated as the z direction. The circumferential direction is the direction of rotation around the axial direction and is illustrated as the y direction. The radial direction is the direction perpendicular to the axial direction and is illustrated as the x direction. Because the pile bodies 21, 22, the inner fitting member 3, and the outer fitting member 4 are arranged so that they are coaxial after being connected, the axial, circumferential, and radial directions are common to these components.

The inner fitting member 3 and the outer fitting member 4 are joined to the axial ends of the pile main bodies 21 and 22 at welds 23 and 24, respectively. The pile main bodies 21 and 22 joined to the inner fitting member 3 and the outer fitting member 4 are connected by rotating the inner fitting member 3 axially to a predetermined position while it is fitted inside the outer fitting member 4 and fixing it with a rotation prevention key (not shown). The inner fitting member 3 includes a joint 31 joined to the pile main body 21 and a fitting portion 32 (first fitting portion) formed adjacent to the joint 31 and fitting to the inside of the outer fitting member 4. In this embodiment, the fitting portion 32 includes a reduced diameter portion 321 whose outer diameter gradually decreases toward the end opposite the pile main body 21 in the axial direction, and multiple protrusions 322 (first protrusions) protruding outward from the reduced diameter portion 321 and formed with gaps in between in the circumferential direction. The length (circumferential dimension) of the protrusions 322 is smaller than the gaps between the protrusions 322 in the circumferential direction.

On the other hand, the outer fitting member 4 includes a joint portion 41 that is joined to the pile main body 22, and a fitting portion 42 (second fitting portion) that is formed adjacent to the joint portion 41 and fits onto the outside of the inner fitting member 3. In this embodiment, the fitting portion 42 includes an expanded diameter portion 421 whose inner diameter gradually increases toward the end opposite the pile main body 22 in the axial direction, and multiple protruding portions 422 (second protruding portions) that protrude inward from the expanded diameter portion 421 and are formed with gaps in the circumferential direction. The length (circumferential dimension) of the protruding portions 422 is smaller than the gaps between the protruding portions 422 in the circumferential direction. The lengths and spacing (circumferential dimension), thickness (axial dimension), and protruding height (radial dimension) of the protruding portions 322, 422 correspond to each other so that the protruding portions 322, 422 engage with each other when the inner fitting member 3 is rotated axially to a predetermined position while fitted inside the outer fitting member 4.

Pipes 51 and 52 are fluid pipes extending in the axial direction of pile bodies 21 and 22. Pipe 51 (first pipe) is joined to the inner surface of pile body 21, and pipe 52 (second pipe) is joined to the inner surface of pile body 22. If pipes 51 and 52 are steel pipes, they may be welded to the inner surface of pile bodies 21 and 22. Alternatively, pipes 51 and 52 may be fixed using retainers (not shown) welded to the inner surface of pile bodies 21 and 22. As described below, in this embodiment, pipes 51 and 52 are connected via connecting pipe 6. By supplying high-pressure water from the ground to the tip of the steel pipe pile being driven via pipes 51 and 52 and connecting pipe 6, the steel pipe pile can be smoothly driven into the ground (water jet construction method).

As shown in FIG. 2, a through hole 33 is formed near the boundary between the joint portion 31 and the fitting portion 32 of the inner fitting member 3, connecting the inside of the inner fitting member 3 with the outside of the fitting portion 32. A groove 324 is formed in the inclined surface 323 that corresponds to the outer peripheral surface of the fitting portion 32, circumferentially aligned with the through hole 33. Specifically, the groove 324 extends from the exit of the through hole 33 along the inclined surface 323 to the end of the fitting portion 32 on the opposite side from the pile main body 21. Meanwhile, a groove 424 is formed in the inclined surface 423 that corresponds to the inner peripheral surface of the fitting portion 42 of the outer fitting member 4. The groove 424 of the outer fitting member 4 is formed so that its position aligns with the groove 324 of the inner fitting member 3 when the inner fitting member 3 is rotated axially to a predetermined position while fitted inside the outer fitting member 4. Specifically, the groove 424 extends along the inclined surface 423 from the end of the fitting portion 42 facing the pile body 22 to the end opposite the pile body 22. As shown in FIG. 3, when the inner fitting member 3 is fitted inside the outer fitting member 4 and rotated axially to a predetermined position, the grooves 424 of the outer fitting member 4 face each other, forming a passage through which the connecting pipe 6 connecting the piping 51 and 52 passes.

In the above example, for example, if the gap between the inclined surfaces 323, 423 is large when the inner fitting member 3 is fitted inside the outer fitting member 4 and rotated axially, and the dimension by which the groove widens the passage does not need to be large, or if one of the fitting portions 32, 42 has a sufficient thickness to form a deep groove, then groove 324 or groove 424 may be formed on one of the inclined surfaces 323, 423, and no groove may be formed on the other. Furthermore, if the gap between the inclined surfaces 323, 423 when the inner fitting member 3 is fitted inside the outer fitting member 4 and rotated axially is equal to or greater than the outer diameter of the connecting pipe 6, then no groove may be formed on either of the inclined surfaces 323, 423. In other words, in this embodiment, the passage through which the connecting pipe 6 passes is formed in the portion where the gaps of the protrusions 322 and the gaps of the protrusions 422 are aligned in the circumferential direction when the inner fitting member 3 is rotated to a predetermined position while fitted inside the outer fitting member 4, i.e., the portion where the positions of the inclined surfaces 323, 423 are aligned, and grooves 324 and 424 are formed in at least one of the inclined surfaces 323, 423 as needed. Note that "aligned portion" does not necessarily mean that the circumferential positions of the inclined surfaces 323, 423 are completely aligned; it is sufficient that the positions of the inclined surfaces 323, 423 at least partially overlap in the circumferential direction.

Furthermore, in this embodiment, notches 34, 44 are formed on the outer peripheral surfaces of the inner fitting member 3 and the outer fitting member 4, circumferentially aligned with the passage formed by the through hole 33 and the grooves 324, 424. The openings formed by the notches 34, 44 allow the process of inserting the connecting pipe 6 into the through hole 33 and the grooves 324, 424 to connect the piping 51, 52 from the outside after the pile bodies 21, 22 are connected, as described below. As long as an opening large enough for such construction can be formed, only the notch 34 may be formed in the inner fitting member 3, or only the notch 44 may be formed in the outer fitting member 4. In addition, in the illustrated example, the notches 34, 44 are formed with a width similar to that of the through hole 33 but wider than the width (circumferential dimension) of the grooves 324, 424. However, the width of the notches 34, 44 may be narrower than that of the through hole 33 and the grooves 324, 424. The width of the through hole 33 and the width of the grooves 324, 424 do not necessarily have to be the same, so as an example, the width of the notches 34, 44 may be at least 60% of the narrower of these widths.

As shown in FIG. 3 , in this embodiment, pipes 51 and 52 are connected by a connecting pipe 6 that passes through a passage formed by through-hole 33 and grooves 324 and 424. Connecting pipe 6 is connected to pipe 51 with connector 71 and to pipe 52 with connector 72. In the illustrated example, connecting pipe 6 is divided into two parts, connecting pipes 61 and 62, which are connected by connector 73. In other examples, connecting pipe 6 may be a single pipe. Depending on the connection method, as described below, connecting pipe 6 may be a flexible pipe made of resin, rubber, metal fiber, or the like; a metal pipe processed into a bellows shape; or a rigid tubular member such as a steel pipe or plastic pipe. For example, part of connecting pipe 6 may be made of a flexible pipe, and the other part may be made of a rigid tubular member.

In other examples, part or all of the connecting pipe 6 may be an extension of the pipe 51 or the pipe 52. For example, the portion corresponding to the connecting pipe 61 in the example shown in FIG. 3 may be an extension of the pipe 51, and the portion corresponding to the connecting pipe 62 may be an extension of the pipe 52. Alternatively, the connecting pipe 6, which is a single pipe, may be an extension of either the pipe 51 or the pipe 52. In these cases, the connecting structure 1 does not include the connecting pipe 6. Also, for example, the portion corresponding to the connecting pipe 61 may be an extension of the pipe 51, and the connecting pipe 6 may consist of only the portion corresponding to the connecting pipe 62. Similarly, the portion corresponding to the connecting pipe 62 may be an extension of the pipe 52, and the connecting pipe 6 may consist of only the portion corresponding to the connecting pipe 61.

After the process of connecting the pipes 51 and 52 through the openings formed by the notches 34 and 44 is completed, the cover 7 is attached to the notches 34 and 44 to seal the openings. A groove may be formed on the inner surface of the cover 7 to ensure sufficient space for the connecting pipe 6 to pass through even after installation. By attaching the cover 7, deformation when high-pressure water is passed through the connecting pipe 6, which is, for example, a flexible pipe, is prevented and the connecting pipe 6 is prevented from protruding outside the steel pipe pile and encountering resistance from the ground. This protection provided by the cover 7 allows the connecting pipe 6 to be made of a soft, inexpensive material that can withstand water pressure. Furthermore, since the connection of the pile bodies 21 and 22 using the inner fitting member 3 and the outer fitting member 4 is a construction method that does not require on-site welding for connection, it is preferable to attach the cover 7 using a method other than welding, such as bolting, by inserting bolts from the outside of the cover 7 into threaded holes formed in the inner fitting member 3 and the outer fitting member 4.

Note that, for example, in cases where there is no possibility that the connecting pipe 6 will protrude outside the steel pipe pile even under water pressure, or where the connecting pipe 6 is made of a material with sufficient strength and does not require protection, the lid 7 may not be attached and the connecting pipe 6 may be exposed. Alternatively, to protect the connecting pipe 6 without the lid 7, the opening formed by the notches 34, 44 may be filled with a solidifying material.

4 and 5 are diagrams showing examples of connectors for connecting a pipe and a connecting pipe. In the example shown in FIG. 4, connector 71A is composed of a threaded joint 711 joined to pipe 51 and a bushing 712 joined to connecting pipe 61. In this example, pipe 51 and connecting pipe 61 are connected by threading a male thread formed on the outer periphery of bushing 712 into a female thread formed on the inner periphery of threaded joint 711. In the example shown in FIG. 5, connector 72B is composed of an outer pipe 721 joined to pipe 52, an inner pipe 722 joined to connecting pipe 62, and an O-ring 723. In this example, pipe 52 and connecting pipe 62 are connected by inserting inner pipe 722 into pipe 52 through outer pipe 721 and sealing the gap between outer pipe 721 and inner pipe 722 with O-ring 723. Note that the above example of connector 71A can also be applied to connector 72, and the example of connector 72B can also be applied to connector 71.

Figure 6 shows an example of a connector for connecting connecting pipes. In the example shown in Figure 6, connector 73A is composed of an inner pipe 731 joined to connecting pipe 61, a sheath pipe 732 joined to connecting pipe 62, and a waterproof rubber 733. In this example, connecting pipes 61 and 62 are connected by inserting inner pipe 731 into sheath pipe 732 and covering the joint from the outside with waterproof rubber 733. Note that connectors 71, 72, and 73 are not limited to the examples described above with reference to Figures 4 to 6, and various structures such as couplers known as connecting structures for fluid pipes can be used.

7 is a schematic diagram illustrating a first example of a method for connecting steel pipe piles according to the first embodiment of the present invention. As shown in (a), in this embodiment, when the inner fitting member 3 is fitted inside the outer fitting member 4 and rotated axially to a predetermined position, the circumferential positions of the through hole 33 (not shown) of the inner fitting member 3, the groove 324 (not shown) formed in the inclined surface 323 (not shown), the groove 424 (not shown) formed in the inclined surface 423 of the outer fitting member 4, and the notches 34, 44 formed in the inner fitting member 3 and the outer fitting member 4 are aligned. Therefore, as shown in (b), a connecting pipe 62 can be inserted through the opening formed by the notches 34, 44, and then, as shown in (c), the connecting pipe 62 can be inserted through the grooves 324, 424 to connect to the piping 52. Although not shown, a connecting pipe 61 is then inserted through the opening of the notches 34, 44 in a similar manner and inserted into the through hole 33 to connect to the piping 51. The connecting pipe 61 may be connected to the piping 51 in advance. Finally, by connecting the connecting pipes 61 and 62 near the openings of the notches 34 and 44, the piping 51 and 52 can be connected via the connecting pipe 6. After that, a step of attaching the lid 7 to the notches 34 and 44 may be performed.

Figure 8 is a schematic diagram showing a second example of a method for connecting steel pipe piles according to the first embodiment of the present invention. In this example, as shown in (a), before fitting the inner fitting member 3 inside the outer fitting member 4, a wire 74 is connected to the connecting pipe 62 stored in advance inside the piping 52. Then, as shown in (b), the inner fitting member 3 is fitted inside the outer fitting member 4. At this time, the wire 74 is pulled out from the cutout 34 or cutout 44 to the outside of the inner fitting member 3 and the outer fitting member 4. Because the wire 74 is thin, it is possible to avoid interference with the protrusions 322, 422 even when the inner fitting member 3 is rotated relative to the outer fitting member 4. After rotating the inner fitting member 3 to a predetermined position relative to the outer fitting member 4 as shown in (c), the wire 74 is pulled to pull the connecting pipe 62 from the piping 52 as shown in (d). This allows the connection pipes 61 and 62, which extend from the pipe 51 via the through-hole 33, to be connected near the openings of the notches 34 and 44. In a similar manner, the connection pipe 61 that has been stored inside the pipe 51 in advance may be pulled out. Alternatively, the connection pipe 6 stored in one of the pipes 51, 52 may be pulled out and connected directly to the other of the pipes 51, 52.

Figure 9 is a schematic diagram illustrating an example of a connection structure and connection method for steel pipe piles according to a second embodiment of the present invention. In the second embodiment, the passage through which the connecting pipe 6 passes is formed by a notch 325A (first protruding portion notch) formed in the circumferential middle of the protruding portion 322 of the inner fitting member 3 and a notch 425A (second protruding portion notch) formed in the circumferential middle of the protruding portion 422 of the outer fitting member 4. As shown in (a), the notches 325A and 425A are formed so that their circumferential positions are aligned when the inner fitting member 3 is fitted inside the outer fitting member 4 and rotated to a predetermined position. The connecting pipe 6 can be inserted through the passage formed by the aligned positions of the notches 325A and 425A from the openings of the notches 34 and 44 through the through-hole 33 and the notches 325A and 425A, as shown in (b) and (c), to connect the piping 51 and 52.

Figure 10 is a schematic diagram showing an example of a connection structure and connection method for a steel pipe pile according to a third embodiment of the present invention. In this embodiment, the length (circumferential dimension) of at least one of the protrusions 322, 422 arranged circumferentially on the inner fitting member 3 and the outer fitting member 4 is made shorter than the other protrusions 322, 422 due to cutouts (first and second protrusion cutouts) formed at the circumferential ends. The space created by these cutouts serves as a passageway for the connecting pipe 6. As shown in (a), if the connecting pipe 62 on the outer fitting member 4 is positioned along the cutout portion of the protrusion 422A, the connecting pipe 62 does not interfere with the protrusions 322A, 422A before and after the inner fitting member 3 is fitted inside the outer fitting member 4 and rotated in a specific direction, as shown in (b). As shown in (c), when the inner fitting member 3 is rotated to a predetermined position, the circumferential ends of the protrusions 322A and 422A, i.e., the positions of the notches, align to form a passage, and this passage aligns with the position of the through-hole 33. By connecting the connecting pipes 61 and 62, which are separately connected to the pipe 51, the pipes 51 and 52 can be connected via the connecting pipe 6.

In the embodiment of the present invention described above, the pipes 51, 52 are connected through the through hole 33 formed in the inner fitting member 3 and the passage formed between the fitting portion 32 of the inner fitting member 3 and the fitting portion 42 of the outer fitting member 4. The pipes 51, 52 may be connected by the connecting pipe 6, or by extensions of either or both of the pipes 51, 52. No additional components are required to secure the connecting pipe 6 or the extensions of the pipes 51, 52. Furthermore, the pipes 51, 52 and the connecting pipe 6 can be connected from the outside after the pile bodies 21, 22 are connected through openings formed by the notches 34, 44 on the outer surfaces of the inner fitting member 3 and the outer fitting member 4, respectively, allowing for highly safe and stable construction. In the section where the inner fitting member 3 and outer fitting member 4 of the connecting structure 1 are fitted together, the extension of the connecting pipe 6 or piping 51, 52 does not pass inside the stepped portion where the inner fitting member 3 or outer fitting member 4 protrudes inward, and is therefore less likely to encounter resistance from, for example, soil (blocking soil) flowing into the interior from the tip of the steel pipe pile. Therefore, the pipe connection is less likely to come loose, even in hard ground or ground with a lot of blockage soil. Even in such cases, the connecting structure 1 can be applied to omit on-site welding, allowing for the construction of a steel pipe pile foundation with improved workability.

While the above describes an example in which the fitting portions 32, 42 of the inner fitting member 3 and outer fitting member 4 included in the connecting structure 1 are formed with reduced diameter portions 321, expanded diameter portions 421, and protrusions 322, 422, the configuration of the inner fitting member and outer fitting member is not limited to this example. For example, the pile bodies may be connected to each other by fitting the inner fitting member to the outer fitting member and threading a male thread formed on the outer periphery of the inner fitting member into a female thread formed on the inner periphery of the outer fitting member. In this case, too, by forming a through hole in the inner fitting member and forming a passage using a groove formed on at least one of the outer periphery of the fitting portion of the inner fitting member and the inner periphery of the fitting portion of the outer fitting member, and aligning these circumferentially, pipes can be connected to each other in the same way as in the embodiment described above.

The above describes in detail preferred embodiments of the present invention with reference to the accompanying drawings, but the present invention is not limited to these examples. It is clear that a person skilled in the art of the technology to which the present invention pertains could conceive of various modifications or alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

1...connecting structure, 21, 22...pile main body, 23, 24...welded portion, 3...inner fitting member, 31...joint portion, 32...fitting portion, 321...reduced diameter portion, 322, 322A...protruding portion, 323...inclined surface, 324...groove portion, 325A...notch, 33...through hole, 34...notch, 4...outer fitting member, 41...joint portion, 42...fitting portion, 421...expanded diameter portion, 422, 422A...protruding portion, 423 ...inclined surface, 424...groove portion, 425A...notch, 44...notch, 51, 52...piping, 6, 61, 62...connecting pipe, 7...cover body, 71, 71A, 72, 72B, 73, 73A...connector, 74...wire, 711...threaded joint, 712...bushing, 721...outer tube, 722...inner tube, 723...O-ring, 731...inner tube, 732...tube, 733...water-stop rubber.

Claims (16)

A connection structure for steel pipe piles that axially connects first and second pile bodies,
The pile includes an inner fitting member joined to the end of the first pile body in the axial direction, an outer fitting member joined to the end of the second pile body in the axial direction, a first pipe joined to the inner peripheral surface of the first pile body, and a second pipe joined to the inner peripheral surface of the second pile body,
the inner fitting member includes a first fitting portion that fits into the inside of the outer fitting member, and a through hole that communicates the inside of the inner fitting member with the outside of the first fitting portion,
the outer fitting member includes a second fitting portion that fits onto the outside of the inner fitting member,
the first pipe and the second pipe are connected through the through hole and a passage formed between the first fitting portion and the second fitting portion;
A connecting structure for steel pipe piles, in which an opening is formed by a notch provided on the outer surface of at least one of the inner fitting member and the outer fitting member, circumferentially aligned with the through hole and the passage. The steel pipe pile connection structure described in claim 1, further comprising a connecting pipe connected to the first pipe and the second pipe and passing through the through hole and the passage. The steel pipe pile connection structure described in claim 1, wherein an extension of the first pipe or the second pipe passes through the through hole and the passage. The steel pipe pile connection structure of any one of claims 1 to 3, further comprising a cover attached to the cutout. A steel pipe pile connection structure as described in any one of claims 1 to 4, wherein the passage is formed by a groove formed in at least one of the first fitting portion and the second fitting portion. The first fitting portion includes a reduced diameter portion whose outer diameter gradually decreases toward the end opposite the first pile body in the axial direction, and a plurality of first protrusions formed on the outside of the reduced diameter portion with gaps in the circumferential direction,
The second fitting portion includes an expanded diameter portion whose inner diameter gradually increases toward the end opposite the second pile body in the axial direction, and a plurality of second protrusions formed inside the expanded diameter portion with gaps in the circumferential direction,
A connection structure for steel pipe piles as described in any one of claims 1 to 5, wherein the first protrusion and the second protrusion are configured to engage with each other when the inner fitting member is fitted inside the outer fitting member and rotated to a predetermined position. The steel pipe pile connection structure described in claim 6, wherein when the inner fitting member is rotated to the predetermined position while fitted inside the outer fitting member, the passage is formed in the portion where the gap portion of the first protrusion and the gap portion of the second protrusion are aligned in the circumferential direction. a first protrusion notch is formed in an intermediate portion or an end portion in the circumferential direction of at least one of the first protrusions;
a second protrusion notch is formed in an intermediate portion or an end portion in the circumferential direction of at least one of the second protrusions;
A connection structure for steel pipe piles as described in claim 6, wherein when the inner fitting member is rotated to the predetermined position while fitted inside the outer fitting member, the positions of the first protrusion notch and the second protrusion notch in the circumferential direction are aligned, thereby forming the passage. A steel pipe pile foundation including at least one steel pipe pile connection structure according to any one of claims 1 to 8. A method for connecting steel pipe piles that axially connects first and second pile bodies,
A step of fitting a first fitting portion formed on an inner fitting member joined to the axial end portion of the first pile body into an inside of a second fitting portion formed on an outer fitting member joined to the axial end portion of the second pile body;
and connecting a first pipe joined to the inner peripheral surface of the first pile body and a second pipe joined to the inner peripheral surface of the second pile body through an opening formed by a notch provided on the outer peripheral surface of at least one of the inner fitting member and the outer fitting member,
the first pipe and the second pipe are connected through a through-hole that communicates the inside of the inner fitting member with the outside of the first fitting portion, and a passage formed between the first fitting portion and the second fitting portion;
A method for connecting steel pipe piles, wherein the notch and the opening are formed to circumferentially align with the through hole and the passage. The method for connecting steel pipe piles described in claim 10 further includes the step of attaching a cover to the notch after connecting the first pipe and the second pipe. a connecting pipe is used to connect the first pipe and the second pipe;
the connecting pipes include a first connecting pipe connected to the first piping and a second connecting pipe connected to the second piping,
12. The method for connecting steel pipe piles according to claim 10 or claim 11, further comprising the step of connecting the first connecting pipe and the second connecting pipe to each other after the step of inserting the connecting pipe into the passage. a connecting pipe is used to connect the first pipe and the second pipe;
A method for connecting steel pipe piles according to any one of claims 10 to 12, wherein the step of connecting the first pipe and the second pipe includes a step of pulling out the connecting pipe that has been stored in advance inside at least one of the first pipe and the second pipe. The first fitting portion includes a reduced diameter portion whose outer diameter gradually decreases toward the end opposite the first pile body in the axial direction, and a plurality of first protrusions formed on the outside of the reduced diameter portion with gaps in the circumferential direction,
The second fitting portion includes an expanded diameter portion whose inner diameter gradually increases toward the end opposite the second pile body in the axial direction, and a plurality of second protrusions formed inside the expanded diameter portion with gaps in the circumferential direction,
14. A method for connecting steel pipe piles as described in any one of claims 10 to 13, wherein the step of fitting the first fitting portion into the inside of the second fitting portion includes a step of rotating the inner fitting member to a predetermined position while the inner fitting member is fitted into the inside of the outer fitting member, thereby engaging the first protrusion and the second protrusion with each other. The method for connecting steel pipe piles described in claim 14, wherein the step of connecting the first pipe and the second pipe includes rotating the inner fitting member to the predetermined position while it is fitted inside the outer fitting member, and then inserting connecting pipes connected to the first pipe and the second pipe, or extensions of the first pipe or the second pipe, into the passage. the passage is formed at a position where it does not interfere with the first protrusion and the second protrusion before and after the inner fitting member is rotated to the predetermined position in a state where it is fitted inside the outer fitting member,
15. The method for connecting steel pipe piles according to claim 14, wherein the step of connecting the first pipe and the second pipe includes a step of placing a connecting pipe connected to the second pipe or an extension of the second pipe in the passage before rotating the inner fitting member while fitted inside the outer fitting member.